ResourceAn IL-27-Driven Transcriptional Network Identifies Regulators of IL-10 Expression across T Helper Cell SubsetsGraphical AbstractTemporal RNA profiling TFs associated with Il10 expression Naive T cell Tr1 + IL-27 IL-10+ IL-10- IL-10 Th1 Th1 0h 72h Th2 Th2 17 time points Th17 Th17 Prdm1 Treg Treg Maf ... In vitro & in vivoTranscriptional network Meta analysis of in-house driven by IL-27 and public RNA-seq Colon T cells scRNA-seq TF TF Normal colon CCR2 TF WT Treg TF Il10 IL-10 TF TF CCR7 CD103 TF Prdm1/Maf XCL1 DKO Treg RNA-seq of 16 TF KOs CXCL-10 ColitisLT-α IFN-γHighlightsd IL-27-driven transcriptional network in CD4 T cells unravels key Il10 regulators d Systematic characterization of the function of 16 Il10 regulators by RNA-seq d Identification of transcription factors associated with Il10 in multiple T cell subsets d Prdm1 and Maf are critical for Il10 production and intestinal immune homeostasisZhang et al., 2020, Cell Reports 33, 108433 November 24, 2020 ª 2020 The Authors. https://doi.org/10.1016/j.celrep.2020.108433Authors Huiyuan Zhang, Asaf Madi, Nir Yosef, ..., Ana C. Anderson, Aviv Regev, Vijay K. Kuchroo Correspondence asafmadi@tauex.tau.ac.il (A.M.), aregev@broadinstitute.org (A.R.), vkuchroo@evergrande.hms.harvard.edu (V.K.K.) In Brief Zhang et al. construct a transcriptional network for IL-27-mediated Il10 production in CD4 T cells, characterize the function of 16 Il10 regulators, and uncover the role of two transcription factors, Prdm1 and Maf, in driving Il10 production in all T helper cells and in maintaining immune homeostasis in the colon.ll OPEN ACCESS llResource An IL-27-Driven Transcriptional Network Identifies Regulators of IL-10 Expression across T Helper Cell Subsets Huiyuan Zhang,1,14 Asaf Madi,1,2,14,* Nir Yosef,1,3 Norio Chihara,1,4 Amit Awasthi,1,5 Caroline Pot,1,6 Conner Lambden,1,7 Amitabh Srivastava,8 Patrick R. Burkett,1,9 Jackson Nyman,1,7 Elena Christian,1,7 Yasaman Etminan,1 Annika Lee,1 Helene Stroh,1 Junrong Xia,1 Katarzyna Karwacz,1,10 Pratiksha I. Thakore,7 Nandini Acharya,1 Alexandra Schnell,1 ChaoWang,1 Lionel Apetoh,1,11 Orit Rozenblatt-Rosen,7 AnaC. Anderson,1 Aviv Regev,7,12,13,* and Vijay K. Kuchroo1,7,15,* 1Evergrande Center for Immunologic Diseases and Ann Romney Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, Boston, MA, USA 2Department of Pathology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel 3Department of Electrical Engineering and Computer Science and Center for Computational Biology, University of California, Berkeley, CA, USA 4Division of Neurology, Kobe University Graduate School of Medicine, Kobe, Japan 5Center for Human Microbial Ecology, Translational Health Science and Technology Institute(an autonomous institute of the Department of Biotechnology, Government of India), NCR Biotech Science Cluster, Faridabad, India 6Laboratories of Neuroimmunology, Division of Neurology and Neuroscience Research Center, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland 7Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, USA 8Department of Pathology, Brigham and Women’s Hospital, Boston, MA, USA 9Biogen, 300 Binney St., Cambridge, MA, USA 10Regeneron Pharmaceuticals, 777 Old Saw Mill River Road, Tarrytown, NY, USA 11INSERM, U1231, Dijon, France 12Howard Hughes Medical Institute, Department of Biology, Koch Institute and Ludwig Center, Massachusetts Institute of Technology, Cambridge, MA, USA 13Genentech, 1 DNA Way, South San Francisco, CA, USA 14These authors contributed equally 15Lead Contact *Correspondence: asafmadi@tauex.tau.ac.il (A.M.), aregev@broadinstitute.org (A.R.), vkuchroo@evergrande.hms.harvard.edu (V.K.K.) https://doi.org/10.1016/j.celrep.2020.108433SUMMARYInterleukin-27 (IL-27) is an immunoregulatory cytokine that suppresses inflammation through multiple mech- anisms, including induction of IL-10, but the transcriptional network mediating its diverse functions remains unclear. Combining temporal RNA profiling with computational algorithms, we predict 79 transcription fac- tors induced by IL-27 in T cells. We validate 11 known and discover 5 positive (Cebpb, Fosl2, Tbx21, Hlx, andAtf3) and 2 negative (Irf9 and Irf8) Il10 regulators, generating an experimentally refined regulatory network for Il10. We report two central regulators,Prdm1 andMaf, that cooperatively drive the expression of signature genes induced by IL-27 in type 1 regulatory T cells, mediate IL-10 expression in all T helper cells, and deter- mine the regulatory phenotype of colonic Foxp3+ regulatory T cells. Prdm1/Maf double-knockout mice develop spontaneous colitis, phenocopying ll10-deficient mice. Our work provides insights into IL-27-driven transcriptional networks and identifies two shared Il10 regulators that orchestrate immunoregulatory pro- grams across T helper cell subsets.INTRODUCTION Interleukin-27 (IL-27) is an immunoregulatory cytokine that regu- lates immune responses bymultiple mechanisms, including inhi- bition of differentiation of effector T cell subsets (Artis et al., 2004; Stumhofer et al., 2006; Villarino et al., 2006; Yoshida and Hunter, 2015), induction of a ‘‘co-inhibitory’’ gene module to promote T cell exhaustion (Chihara et al., 2018; DeLong et al., 2019), and polarization of Foxp3+ regulatory T (Treg) cells to a T-bet+C This is an open access article under the CC BY-Nsubset that specializes in controlling Th1 immunity (Hall et al., 2012). In addition, we and others have described that IL-27 can differentiate naive T cells into type 1 regulatory T (Tr1) cells (Awasthi et al., 2007; Fitzgerald et al., 2007; Stumhofer et al., 2007; Wang et al., 2011), a Foxp3 IL-10-producing regulatory cell population identified in mouse and human, that suppresses tissue inflammation, autoimmune reactions, and graft versus host disease (GVHD) largely via IL-10 (Roncarolo et al., 1988). IL-27 has the unique capability to induce IL-10 production fromell Reports 33, 108433, November 24, 2020 ª 2020 The Authors. 1 C-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). ll OPEN ACCESS Resourcea wide range of cell types, including Th1, Th2, Th17, and Treg cells (Awasthi et al., 2007; Fitzgerald et al., 2007; Hall et al., 2012; Stumhofer et al., 2006, 2007). Consistent with these obser- vations, Il27ra/ T cells have defects in producing IL-10 in vitro and in vivo (Batten et al., 2008). Il27ra/ mice suffer from lethal immunopathology in parasitic diseases, which is reminiscent of Il10/mice (Villarino et al., 2003), and they aremore susceptible to experimental autoimmune encephalomyelitis (Batten et al., 2006; Fitzgerald et al., 2007). The molecular mechanisms by which IL-27 induces these diverse regulatory functions in T cells are not fully understood. The anti-inflammatory cytokine IL-10 has an indispensable role in maintaining immune tolerance and limiting immunopa- thology during homeostasis, inflammation, infection, and auto- immune diseases (Iyer and Cheng, 2012; Ouyang et al., 2011). Mutations in IL-10 or IL-10R lead to early-onset inflammatory bowel disease (IBD) in humans (Shim, 2019), and mice deficient in IL-10 or IL-10R develop spontaneous colitis (Ku€hn et al., 1993; Spencer et al., 1998). Importantly, all T helper cell subsets, including Th1, Th2, and Th17 cells, can produce IL-10 tomitigate hyperactive immune responses (Gabrysová et al., 2014). Several transcription factors (TFs) have been shown to regulate IL-10 (Gabrysová et al., 2014; Zhang and Kuchroo, 2019). However, a comprehensive model that systemically examines the dynamic transcriptional network that regulates Il10 in a temporal context of induction and maintenance is lacking. Here we combined computational algorithms with high-reso- lution temporal transcriptional profiling to predict the TF network driven by IL-27 during Tr1 differentiation. Network analysis sys- tematically identified regulators for Il10 and highlighted Prdm1 and Maf as two central nodes of the Il10 regulatory circuits that cooperatively promoted IL-10 production not only in Tr1 cells but also in Th1, Th2, Th17, and Treg cells. Genetic deletion of Prdm1 andMaf in T cells (Prdm1/Maf DKO), but not either alone, led to spontaneous colitis in mice that exhibits features of human IBD, underscoring the importance of Prdm1 andMaf crosstalk in regulating immune homeostasis in vivo. Single-cell RNA sequencing (scRNA-seq) of colonic CD4+ T cells in DKO mice identified a unique cluster of Treg cells that lost Il10 expression and acquired proinflammatory signatures. RESULTS Building a Predictive Model for the IL-27-Driven Transcriptional Program in CD4 T Cells by High- Resolution Temporal Transcriptional Profiling To understand the gene expression program induced by IL-27 in CD4 T cells, we activated naive CD4 T cells in vitro in the pres- ence (Tr1) or absence (Th0) of IL-27 for 72 h and performed whole-genome microarrays at 17 time points. 790 genes were differentially expressed in Tr1 cells compared with Th0 cells, which partitioned into 24 co-expression clusters with distinct temporal profiles (Figure 1A). After activation with IL-27, the cells underwent several transcriptional waves before acquiring a sta- ble phenotype (Figure 1B): an early phase from 0–4 h, when the global transcriptional profile changes dynamically; a stable early phase from 8–20 h; an intermediate phase from 25–42 h; and a late phase from 48–72 h. The dynamic transcriptional changes2 Cell Reports 33, 108433, November 24, 2020during the first 4 h are a distinct feature of Tr1 cell differentiation compared with Th17 cells, whichmanifest a relatively stable pro- file during the early phase from 0–2 h (Yosef et al., 2013). To identify TFs that drive the distinct transcriptional waves, we hypothesized that genes co-expressed in a cluster (Figure 1A) are likely to share regulators that are active at the relevant time point. We predicted regulator-target associations in the IL-27-driven transcriptional programs based on significant overlap between genes in a specific cluster and a regulator’s putative targets in a regulator-target association database (Yosef et al., 2013). This generated a predictive network containing 79 TFs that were puta- tive regulators of the gene clusters induced by IL-27 (Figure 1C). The 79 TFs fall into six major expression patterns, each containing both knownand previously uncharacterized regulators, that are (1) highly expressed during the dynamic early phase (0–4 h), including Irf1 and Batf, which are the pioneer TFs of Tr1 cell differentiation (Karwacz et al., 2017), as well as Eomes (Zhang et al., 2017); (2) increased during the stable early phase (8–20 h), including Stat1 and Stat3, which mediate signaling downstream of the IL-27 re- ceptor (Stumhofer et al., 2007) and IL-21 receptor (Leonard and Wan, 2016; Pot et al., 2009); (3) increased during the intermediate phase (25–42 h), including Ahr (Apetoh et al., 2010); (4) increased during the late phase (48–72 h), such as Prdm1 (Montes de Oca et al., 2016); (5) increased gradually over time, such as Maf (Pot et al., 2009) andHif1a (Mascanfroni et al., 2015); and (6) decreased specifically during the stable early phase and may act as gate- keepers for the IL-27-induced gene program, which, interestingly, include a potent IL-10 inhibitor, Bhlhe40 (Huynh et al., 2018; Lin et al., 2014; Yu et al., 2018). Our computational analysis identified almost all TFs known to be required for Tr1 cells, indicating a good predictive power, and predicted 69 TFs thatwere not implicated in Tr1 differentiation. Experimental Validation of the IL-27 Predicative Network Identifies TFs that Regulate IL-10 In Vitro Because IL-10 production is themost representative feature of IL- 27-induced Tr1 cells, we used IL-10 expression as a readout to validate the predicative IL-27 network. We gathered 24 available knockout mice, differentiated their naive CD4 T cells into Tr1 cells with IL-27, and compared their Il10mRNA levels with the respec- tive controls (Figure 2A). We validated 11 known Il10 regulators in T cells: 8 positive regulators (Prdm1, Stat3, Ahr, Maf, Irf1, Batf, Hif1a, and Nfil3) and 3 negative regulators (Irf4, Bhlhe40, and Ets1) (Huynh et al., 2018; Karwacz et al., 2017; Lee et al., 2012; Lin et al., 2014; Yu et al., 2018). We found that Cebpb, a TF that induces ll10 in M2 macrophages (Liu et al., 2003), was also required for Il10 production in Tr1 cells. Importantly, among the 12 tested factors that were not known to regulate Il10, we discov- ered 4 positive (Atf3, Fosl2, Tbx21, and Hlx) and 2 negative (Irf9 and Irf8) Il10 regulators. These TFs also regulated IL-10 at the pro- tein level (Figure S1A). Of the 24 genetically perturbed TFs, we successfully validated 18 (75%) of our computational predictions. We examined binding of the aforementioned Il10 regulators to the Il10 locus in public chromatin immunoprecipitation sequencing (ChIP-seq) data. ATF-3 (Garber et al., 2012), T-bet (Nakayamada et al., 2011), Fosl2 (Ciofani et al., 2012), and IRF8 (Xu et al., 2015) have significant binding in the Il10 locus, some of which lies in chromatin-accessible regions in Tr1 cells ll Resource OPEN ACCESS A B C 72 Id3 60 6 Pou2f2 1 Rorc54 Bhlhe40 Nfyb 48 Zkscan6 42 JunbAtf6 36 5 Fli1 Klf10 30 2 Hif1a 25 MafSp4 20 Cebpb Jarid2 3 18 Myst4 16 Tulp4Tle6 14 Klf7 4 8 Chd74 Hlx 5 4 Sertad1Fosl2 2 Sap30 6 1 Id27 Ets1 0.5 Prdm1 8 Fosb 9 0.5 1 2 4 8 14 16 18 20 25 30 36 42 48 54 60 72 Sox4 Time (h) Rai1Arid5a 10 3 Bcl3 0 0.4 0.8 Nfe2L2 11 Pearson Batf3Ahr correlation Satb1 12 Nfil3 Atf3 Litaf Klf6 13 Crem Gfi1 14 Gtf3c5 15 2 Etv6 16 Mllt6 17 18 JunNotch1 19 Tbx21 Stat3 20 Stat1Pml Myb Nrip1 21 Daxx Irf4 Hivep1 Nfkbia Ets2 Eomes 22 Notch2 Plagl1 Irf1 Irf8 Irf9 1 Nfkb2 Mbnl3 Zbtb12 Stat2 Irf7 23 Trim25 Zfp281 Ifi35 Batf Talsss2 Tle1 Gata3 RxrA 24 Utf1 Bc006779 0.5 1 2 4 8 14 16 18 20 25 30 36 42 48 54 60 72 0.5 1 2 4 8 14 16 18 20 25 30 36 42 48 54 60 72 Time (h) Time (h) −3 0 3 −3 0 3 Row z-score Row z-score Figure 1. Building a Predicative Model of the IL-27-Driven Transcriptional Program in CD4 T Cells by High-Resolution Temporal Tran- scriptional Profiling Gene expression profiles during IL-27-driven in-vitro Tr1 differentiation were measured by microarray at 17 time points with the Th0 condition as a control. (A) Relative expression (log2(Tr1/Th0)) of 790 differentially expressed genes (rows). (B) Pearson correlation matrix of the transcriptome at every pair of time points. (C) Relative expression (log2(Tr1/Th0)) of 79 TFs predicted to regulate gene clusters. Underlined are TFs known to regulate Tr1 differentiation. Cluster Time (h)(Figure 2B), indicating that they may directly regulate Il10 tran- scription in Tr1 cells. To investigate whether these TFs can trans- activate or inhibit Il10, we performed luciferase reporter assays in 293T cells using reporters for the proximal Il10 promoter and the CNS-9, HSS+2.98, and HSS+6.45 enhancers (Hedrich and Bream, 2010; Figure 2C). Atf3, Fosl2, and Hlx transactivated the Il10 promoter and the three enhancers. Transactivation by Cebpb was more restricted to the promoter and CNS-9 region, and T-bet only transactivated the CNS-9 region. Irf8 inhibited the baseline activity of the Il10 promoter, HSS+2.98, HSS+6.45, and, to a lesser extent, CNS-9. We found that transactivation of Il10 by the pioneer factor Irf1 (Karwacz et al., 2017) was completely blocked by Irf8 co-expression at the three enhancers but not the proximal promoter (Figure S1B). In contrast, the puta- tive negative regulator Irf9 transactivated Il10 at all four cis-regu- latory sites, indicating that inhibition of Il10 by Irf9 in Tr1 cells may bemediated by indirectmechanisms (Figure 2C). In summary,wevalidated 11 known and discovered 7 direct and indirect regula- tors of Il10 during IL-27-driven Tr1 differentiation. Hlx Regulates Il10 Expression and Tr1 Function In Vivo It has been shown previously that Hlx cooperates with T-bet to promote interferon (IFN)-gexpression in Th1 cells in vitro (Mullen et al., 2002); however, whether it regulates T cell function in vivo and whether it has an immunoregulatory role has not been inves- tigated. To address these questions, we first tested the role ofHlx in amodel of self-limiting inflammation induced by intraperitoneal injection of an anti-CD3 antibody, which spontaneously resolves in a IL-10-dependent manner (Huber et al., 2011; Kamanaka et al., 2006). Because Hlx deficiency is embryonically lethal (Hentsch et al., 1996), we compared Il10 expression in CD4 T cells from Hlx+/ and WT mice following anti-CD3 injection and observed less Il10 inHlx+/ T cells (Figure 2D).We next inves- tigated how Hlx regulates the immunoregulatory function of Tr1Cell Reports 33, 108433, November 24, 2020 3 ll OPEN ACCESS Resource A B 5 kb 7 Il10 6 Positive Negative 5 regulators regulators HSS HSS CNS-9 Promoter 2.98 6.45 4 3 2 ATAC-seq (Tr1) 1 0 ATF-3 -ChIP –1 Fosl2-ChIP –2 –3 T-bet - ChIP –4 –5 IRF8 -ChIP t3 l2 hr 1 tf a fs 1 1 b x 3 3 4 3 2 7 2 1 9 8 1 0 4 ta o A Ir f Ba if1 a l l f t f l f i f f f S H M m x2 bp H i td b N f A ta at 2 Ir Id F l fe I r Ir ts 4 Ir F Pr T Ce S B E e N lh Bh C Control Atf3 Control Cebpb Control Fosl2 Control Hlx 4 3 2.0 1.5 **** **** *** **** 3 **** 1.5 **** **** **** 2 NS **** 1.0NS 2 *** **** 1.0 **** **** 1 0.5 1 0.5 **** 0 0 0.0 0.0 te r 9 8 5 o NS - .9 .4 Control Irf8 Control Irf9 Control Tbx21 m 2 6o C S S 0.6 6 2.0 Pr HS HS * *** 1.5 0.4 4 NS ** NS NS *** *** **** 1.0 ** 0.2 **** 2 ** 0.5 0.0 0 0.0 ert -9 98 45 r te -9 98 45 te r -9 98 45o NS 2 . . . . . . m C S S 6 om CN S 2 6 o S S N S 2 6 ro S S ro S S ro m C S S P H H P H H P HS HS D WT Hlx+/– E Rag–/– WT Tr1 Hlx+/– Tr1 1500 120 * 110 1000 100 p = 0.0001 500 90 0 80 ro l D3 1 2 3 4 5 6 7 8 t on i-C WeeksC an t Figure 2. Experimental Validation of IL-27 Predicative Network Identifies TFs that Regulate Il10 In Vitro and In Vivo (A) Log2 fold change of Il10 mRNA levels in WT versus KO Tr1 cells differentiated in vitro with IL-27 for 72 h, quantified by qPCR. Blue, positive regulator; red, negative regulator; gray, not statistically significant. Data are displayed as mean of 2–3 replicates. (B) Statistically significant ChIP-seq binding sites of ATF-3 ATF-3, Fosl2, T-bet, and IRF8 in the Il10 locus. (C) Luciferase activity in 293T cells transfected with luciferase reporters for the indicated cis-regulatory elements of Il10 and plasmids encoding the depicted TFs. Firefly luciferase activity is normalized to constitutive Renilla luciferase activity. (D) WT andHlx+/mice were injected intraperitoneally (i.p.) with anti-CD3. Il10mRNA in CD4+ T cells MACS purified frommesenteric lymph nodes wasmeasured by qPCR. (E) 53 105 in vitro differentiated WT (diamonds) and Hlx+/(squares) Tr1 cells were transferred i.p. into Rag1/ recipients. Rag1/ (circles) did not receive any cells. Changes in body weight were monitored weekly. n = 5. Il10 mRNA RLU RLU Log2 (fold change) of Il10 mRNA (relative expression) % body weightcells in a T cell transfer colitis model. Rag/ mice receiving wild- type (WT) Tr1 cells were able to maintain their body weight because Tr1 cells normally do not induce colitis. However, the re- cipients of Hlx+/ Tr1 cells lost weight over time, indicating that Tr1 cells haplodeficient for Hlx might lose the regulatory pheno- type and become proinflammatory (Figure 2E).4 Cell Reports 33, 108433, November 24, 2020A Comprehensive Transcriptional Network Focused on Regulation of IL-10 by IL-27 We identified causal genetic targets of the Il10-regulating TFs in the IL-27 network by performing RNA-seq on Tr1 cells geneti- cally deficient in each of them, generating a comprehensive network showing the effect of the TFs on Il10 as well as on the ll Resource OPEN ACCESS A B Positive regulation Betweenness centrality 0.15 Positive regulators Negative regulation 0.00 0.14 Negative regulators Cebpb Stat1 Nfil3 0.10 Fosl2 DowN DowN UP Hlx Maff UP 0.05 Atf3 UP Rorc UP DowN UP DowN UP Jun UP Irf1 UPUP UP 0.00 UP DowN UP 1 af frf4 at 1a t3 ts1 21 h r UP dm M IDowN r B Hi f ta UP Stat2 P S E bx AT UP Ahr UP UP UP UP UP DowN UP UP Pou2f2 UP C Gene expression over time Il10 Tbx2UP 1 UPUP UP UP UP Il1 6DowNUP UPUP 0 DowN UP Control Myb UP UP UP Latency Induction Tr1 UP UP UP UP DowN Stat3 UP DowN UP DowN DowN DowN DowN 5 DowN DowN DowN UP DowN UP Irf8 Maintenance UP DowN Hif1a UP DowN DowN UP UP UP UP DowN UP UP UP DowN Bhlhe40 UP UP 4 Batf DowN UP DowN UP Irf9 UP UP DowN UP UP UP UP DowN Maf DowN Ets1 UP UP DowN Prdm1 DowN Irf4 UP 0.5 1 2 4 8 14 16 18 20 25 30 36 42 48 54 60 72 up Time (h) D Latency Induction Maintenance Bhlhe40 Irf1 Maf Bhlhe40 Fosl2 Maf Fosl2 Maf Prdm1 Prdm1 Prdm1 Irf8 Batf Hif1a Hif1a IL-10 Ets1 IILl-1-100 Ets1 IL-10 Tbx21 Tbx21 Irf9 Nfil3 Nfil3 Stat1 Stat3 Hlx Ahr Hlx Ahr Irf4 Cebpb Cebpb Cebpb Atf3 Figure 3. A Comprehensive Transcriptional Network Focused on Regulation of IL-10 by IL-27 (A) General network of Il10 regulation by TFs in Tr1 cells, visualized using Cytoscape. Edges indicate causal regulatory targets identified using genetic pertur- bation by RNA-seq or qPCR. Blue and red edges indicate positive and negative regulations, respectively. Nodes are colored by betweenness centrality score. (B) Betweenness centrality scores of the regulators in (A). Blue, positive regulator; red, negative regulator. (C) Temporal expression of Il10 in Tr1 versus Th0 cells measured by microarray. (D) Temporal regulation of Il10 in Tr1 cells, divided into 3 main phases: latency (0–20 h), induction (25–48 h), and maintenance (54–72 h). Purple nodes, increased by IL-27; gray nodes, decreased by IL-27. Log2 expression Betweenness centralityexpression of each other (Figure 3A). The network showed dense inter-connectedness betweenmultiple negative and positive Il10 regulators, with substantial cross-regulation between them, ex- plaining how indirect regulators affect Il10 expression through direct regulation of other regulators (Figure 3A). Besides direct inhibition of Il10 by Irf8, the negative regulators, including Irf8, Irf4, Ets1, and Irf9, may regulate Il10 by inhibiting the expression of positive regulators such as Prdm1,Maf, Ahr, and Batf. Except for inhibition of Irf4 by Stat1 and Bhlhe40 by Maf, very few pos- itive regulators inhibited expression of the negative regulators; rather, they reinforced the expression of each other. Quantifica- tion of TF connectivity within the network by betweenness cen- trality score revealed Prdm1 andMaf as themost central positiveregulators and Irf4 as the most central negative regulator, iden- tifying these TFs as central hubs for regulation of Il10 in Tr1 cells (Figure 3B). We observed three distinct phases of Il10 expression during Tr1 differentiation from the temporal microarray data (Figure 3C): a latency phase (0–20 h) with no detectable Il10, an induction phase (20–48 h), and a maintenance phase (48–72 h). To further understand the temporal dynamics of Il10 regulation, we divided the global network into three phase-specific networks based on the regulator’s temporal expression pattern (Figure 3D). The IRFs and Atf3 were mainly increased during the latency phase; Hlx during the induction phase; Tbx21, which has been shown to cooperate with Hlx (Mullen et al., 2002), at the latency andCell Reports 33, 108433, November 24, 2020 5 ll OPEN ACCESS Resourceinduction phase; and Fosl2, during the late induction phase and the maintenance phase. Notably, Prdm1, Maf, and Cebpb were increased at all three phases. Multiple regulators that suppress Il10 were expressed at the latency phase and decreased at the induction and maintenance phases. This may be one of the rea- sons why Il10 induction is relatively late during Tr1 differentiation. Prdm1 andMaf Have Complementary but Indispensable Roles in Regulating Tr1 Identity at the Transcriptional and Chromatin Level Despite being the most central nodes in the Il10 regulatory network, Il10 expression in Prdm1 or Maf single-knockout (cKO) Tr1 cells is only partially reduced, suggesting a comple- mentary relationship between the two TFs. We therefore gener- ated mice that lack both Prdm1 and Maf (DKO) in T cells, using conditional deletion driven by Cd4-Cre. Prdm1/Maf double deficiency led to almost complete loss of Il10 in Tr1 cells (Figure 4A). To investigate how loss of Prdm1 and Maf influences the Il10 regulatory network (Figure 3A), we performed RNA-seq on sin- gle- and double-KO Tr1 cells at 72 h (Figure 4B). Deficiency in Prdm1 and Maf led to a collapse in expression of several TFs important for Il10 expression, including Fosl2, Hif1a, Hlx, and Notch1 (Rutz et al., 2008), which was not observed in Prdm1 or Maf single KO. In addition, a number of other transcriptional regulators that are induced by IL-27 were also specifically decreased in DKO cells, such as Sp1, Ets2, Mbnl3, Klf10, Nfyb, Satb1, Crem, Nfkbia, Chd7, Trim25, Klf6, and Nfkb2, although their role in regulating Il10 remains to be investigated. Furthermore, Prdm1 and Maf transcriptionally regulated each other’s expression (Figure 4B). Bhlhe40, a potent Il10 inhibitor, was increased dramatically in DKO mice, indicating that Prdm1 and Maf are critical not only for driving Il10 expression but also for antagonizing the expression of TFs that repress Il10. Although some positive regulators, such as Irf1 and Atf3, were increased in DKO cells, these early-stage Il10 inducers could not rescue the loss of Il10 in the absence of Prdm1 and Maf, perhaps because of their inability to overcome inhibition (Figure S1B). To assess whether Prdm1 or Maf regulated the chromatin landscape of Tr1 cells, we profiled chromatin accessibility in sin- gle- and double-KO Tr1 cells using Assay for Transposase- Accessible Chromatin with high-throughput sequencing (ATAC-seq). Although the chromatin landscape in the Il10 locus remains largely unchanged in Prdm1 or Maf single-KO cells, we detected a reduction in accessibility at specific enhancer regions in the Il10 locus in DKO cells (Figure 4C). In addition, we found that Fosl2 and Hlx, two other positive regulators of Il10, also became less accessible in DKO but not either single-KO cells (Figure 4C), which is consistent with their gene expression pro- file. Moreover, DKO Tr1 cells showed a unique reduction in chro- matin accessibility in co-inhibitory receptor gene loci such as Ctla4, Pdcd1 (PD-1), Tigit, Havcr2 (Tim-3) (Figure S2), another hallmark of Tr1 cells that is transcriptionally regulated by Prdm1 and Maf (Chihara et al., 2018). In summary, these data suggest that Prdm1 and Maf have complementary but indis- pensable roles in regulating the hallmark genes for Tr1 identity at the transcriptional and chromatin levels.6 Cell Reports 33, 108433, November 24, 2020IL-10 Regulators Are Induced in Diverse IL-10- Producing T Helper Cells All T helper cells can produce IL-10, but the regulation of IL-10 expression in these contexts is unclear. We therefore examined whether the regulators we identified in the IL-27 network were also utilized for IL-10 regulation in other T helper cells. We differentiated naive CD4 T cells from IL-10Thy1.1 reporter mice (10BiT) (Maynard et al., 2007) into Th1, Th2, non-pathogenic Th17 (Th17), pathogenic Th17 (pTh17), and Tr1 cells; sorted out the IL-10+ and IL-10- compartments; and performed RNA-seq. We also analyzed the RNA profiles of IL-10+ versus IL10 T cells purified from several other in vivo and in vitro con- ditions (Boks et al., 2016; Burton et al., 2014; Gagliani et al., 2015; Langenhorst et al., 2012; Neumann et al., 2014; Trandem et al., 2011; Table S1). We identified TFs whose expression was associated with IL-10 in each T cell subset or condition (Figures 5A and 5C) and ranked them based on the number of condi- tions where their expression is enriched in the IL-10-producing compartment (Figures 5B and 5D). Many of the regulators iden- tified in our IL-27 network were also identified by this analysis, including Prdm1, Maf, Hlx, Tbx21, Batf, Nfil3, Ahr, Bhlhe40, and Irf8, indicating that they might also regulate IL-10 in other con- texts (Figures 5A and 5C). Prdm1 and Maf, the two positive reg- ulators with highest centrality in the IL-27 network (Figure 3B), were enriched in the IL-10-producing compartment of all T helper cell subsets (Figure 5B) as well as under many other in vivo and in vitro conditions (Figure 5D), whereas the other TFs were more restricted to certain conditions. A combined ranking scheme of IL-10 regulators evaluating the centrality score in the IL-27 network and generalizability in other IL-10- producing T cell subsets derived from in vitro and in vitro con- texts revealed Prdm1 and Maf as the two top TFs that regulate IL-10 production across T helper cells (Figure 5E). Role of Prdm1 andMaf in Regulating IL-10 in Different T Helper Cells We validated the association of Prdm1 and Maf expression with Il10 in various contexts by qPCR. The IL-10+ compartment of Th1, Th2, Th17, Tr1, and Treg cells expressed higher levels of Prdm1 andMaf than their IL-10 counterparts (Figure 6A). More- over, analysis of public ChIP-seq datasets confirmed binding of Prdm1 andMaf at accessible chromatin regions in the Il10 locus (Figure 6B). These findings further support the hypothesis that Prdm1 and Maf may be critical regulators of IL-10 in multiple settings. We tested the interaction between Prdm1 orMaf in regulating Il10 using luciferase assays. Although Prdm1 alone had very limited capability to transactivate Il10, it significantly enhanced transactivation of Il10 by Maf (Figure 6C), suggesting that co- operation between Prdm1 and Maf is required for optimal IL- 10 production. Of note, the synergistic effect between Prdm1 and Maf is specific to enhancer regions (tested by the interac- tion term in the linear regression model; CNS-9, p = 0.00255; HSS+6.45, p = 0.000154) but not the promoter. We further studied the synergy between Prdm1 and Maf in regulating Il10 in primary CD4 T cells using a gain-of-function approach by transducing Th1, Th2, Th17, Tr1, and Treg cells with retroviruses encoding Prdm1 (MSCV-IRES-Thy1.1) and Maf ll Resource OPEN ACCESS A B Il10 15 WT 3 WT 2 WT 1 10 + + + + + + + + + + + + + + + + + + + + Prdm1 KO 3 + + + + + + + + + + + + + + + + + + + + Prdm1 KO 2 + + + + + + + + + + + + + + + + + + + + Prdm1 KO 1 5 + + + + + + + + + + + + + + + + + Maf KO 3 + + + + + + + + + + + + + + + + + z-score Maf KO 2 0 2 + + + + + + + + + + + + + + + + + Maf KO 1 ol O O O 1r + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + DKO 3 on t cK cK1 f D K 0 −1 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + DKO 2C a dm M −2 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +r DKO 1P C 5 kb [0–18] Control [0–18] Prdm1 cKO [0–18] Maf cKO [0–18] DKO Refseq genes Il10 5 kb [0–18] Control [0–18] Prdm1 cKO [0–18] Maf cKO [0–18] DKO Refseq genes Fosl2 5 kb [0–18] Control [0–18] Prdm1 cKO [0–18] Maf cKO [0–18] DKO Refseq genes Hlx Figure 4. Prdm1 andMafHave Complementary but Indispensable Roles in Regulating Tr1 Identity at the Transcriptional andChromatin Level (A) Naive CD4 T cells from the indicated mice were differentiated in vitro into Tr1 cells with IL-27. Il10 expression was measured by qPCR on day 3. (B and C) Control, Prdm1 cKO, Maf cKO, and Prdm1/Maf DKO Tr1 cells generated as described in (A) were analyzed by RNA-seq (B) and ATAC-seq (C). (B) Heatmap showing expression of 79 predicted regulators in the Tr1 network. ‘‘+’’ indicates statistically significant differential expression. (C) Chromatin accessibility in the Il10, Fosl2, andHlx loci in Tr1 cells of the indicated genotype. Red bars represent regions with differential chromatin accessibility in DKO cells. Relative expression Zbtb12 Tle1 Utf1 Stat1 Junb Rai1 Pml Batf Nrip1 Jun Zfp281 Tbx21 Tulp4 Sp4 Irf4 Hif1a Ets2 Irf9 Fosl2 Mbnl3 Bcl3 Klf10 Nfyb Satb1 Crem Nfkbia Fli1 Chd7 Il10 Id2 Prdm1 Hlx Notch1 Atf6 Trim25 Irf7 Rorc Maf Ets1 Tal2 Cebpb Klf7 Zkscan6 Eomes Hivep1 Gfi1 Gtf3c5 Sox4 Ifi35 Daxx Mllt6 Myb Tle6 Atf3 Bhlhe40 Klf6 Irf1 Sertad1 Stat3 Nfkb2 Id3 Stat2 Nfe2l2 Ahr Litaf Notch2 Fosb Irf8 Sap30 Batf3 Gata3 Jarid2 Arid5a Pou2f2 Rxra Plagl1 Etv6(MSCV-IRES-GFP). IL-10 production was enhanced dramati- cally when Prdm1 and Maf were co-expressed (Figure 6D). Importantly, although Prdm1 and Maf cooperatively promoted IL-10 production across all T helper cells, they did not inhibit production of signature cytokines of the T helper cell subsets (Figure S3). Thus, Prdm1 and Maf enabled expression of a gene module that induced IL-10 in all T helper cell subsets without disrupting their cell differentiation program.Genetic Deficiency of Prdm1 and Maf, but Not Either Alone, in T Cells Leads to Human IBD-like Spontaneous Colitis Driven by a Unique Cluster of Treg Cells IL-10 has a critical role in maintaining intestinal homeostasis. Mutations in IL-10 or IL-10R are associated with human ulcera- tive colitis presenting in early childhood (Zhu et al., 2017). We therefore monitored Prdm1/Maf DKO mice for spontaneous development of colitis. Strikingly, loss of Prdm1 and Maf inCell Reports 33, 108433, November 24, 2020 7 ll OPEN ACCESS Resource A C Th2 Th17 Intr Th1 ana p sT ah l1 a7 nti i. -p C. a Dn 3 8 S ti-m Ca D C D ll 3 lf Ag T in e r1 t s Z esca v s n t to Z ak n ts Zm 21 ic n er Z a iz l Z f 1 p n17 s f 937 T ep934 h D4 to Z Z fpfp 99 2 1 C Z Zff 7 pp88 1 7 Z 0fp 07 86 ZfpZ7f 8 1p−7r6s4 Z Zfp 1 fp6 60 1Zfp 0Zfp55843 ZZ Z ff p fp p 4 5 4 2 3 Z 1 2 f 0p Z 4fp 1Z Zf 3 p 7 fp33627 Z 4fp3 Z 0fp 03 Zfp29 Z 6fp282 Zfp2 Z 6fp 3229 Zfp213 Zfhx4 5730507C01Rik Zeb2 AdnpAff4btb45 Ahr Zmym5 AZ hr Zbtb38 AhrrA Arntl2 Zfp60 Arid t 4f b Zbtb32 1 Zfp516 Arid5b Zbtb1 Ybx1 Atf4 Zfp40 Asb10 Xbp1 Atf6 Z fp26 Bach2 Zfp148 Asb2 Bac Whsc1Wdhd 1 h1 Vdr B Vax2 atf Basp1 Tulp4 Cam b2 Tshz 1 ta2 Bh Ze Tsc22 d1 s1 C lh Trp b C fbd C ea 40 Ugp2 B B ch l Trp5 3 Cr c5l rh le h 3 b e4C 3 1l1 btf Cdk rerf1 re 2 b3l2 sp1 U nC 2x bTo dp2 kn2 T Tfd dTfdp1fam C 4T ef CuT x1 rD C e lp C m Tu 22d3 usc Tcf 4 D nn aa jc T 1 sd rps1 E x1 E j b a 2E f c T 2 2 7l2 Elf f1 1 Tada2 2f f 12 3 a Tc f4 Elf Tbx Tc 2x5 1 srp1 E S o b Su Ea 2f d3 E E f E a l l k f S f2 b Eg 2 4 i ll1 E 3n b Sp p4 EEh r1 4 a pf E 2f m S Et p2re f1 S i3 E lk s1 b Sn a 1 e1 lk3 2 71 S 3S e rcr c c maar 3 Ead 2 tv f8 un x E F t S SSm m adix5 FF vS m 3 F o l mS i1 6 E R x2 F3 o ns l2 5S nx oxsl2 fy l2 Ru b1 tv n u5 RRu x2n Ru B DAtf6 Prdm1 Runx2 5 enriched Maf Sub1 conditions Zeb2 5 enriched Zbtb32 Ahr conditions Mxd1 Prdm1 Runx2 Maf Asb2 4 enriched Bhlhe40 conditions Atf4 Id2 Batf Jun Csda Nfil34 enriched Bcl3 Etv5 conditions Cux1 Foxm1 Ebf1 Hmgb1 Elf4 Hmgb2 Hopx Hmgb3 Ikzf3 3 enriched Litaf Klf7 conditions Nfil3 Med13l Nfat5 Carhsp1 Plekhf1 Crem Pou6f1 E2f4 Rorc E2f7 Runx3 E2f8 Smad3 Hlx Tulp4 Hmga1-rs1 h17 h17 reg D3 D3 Ag and D4 sId2 g s. T xT I T C E S nti - nti- C elf lig C Tre Irf5 3 enriched r1 v . a a s h ed vs p. al nt t o otc rim ate d Irf8 conditions I T 17 i. as ra N p tre Mxd3 S xTh n ntra to le h1 + tDC SA - n 8 Nfatc2 TTr1 E I D4C um a 2 Cd Srebf1 SI H Srebf2 Tbx21 Trerf1 Enriched in IL-10+ compartment Whsc1 Not enriched Xbp1 Zeb2 Th1 Th2 Th1 7 pTh 17 Tr1 E Combined score Score 0.5 2.5 In vivo rank In vitro rank Network rank 0.0 1.0 Norm. ranking score (legend on next page) 8 Cell Reports 33, 108433, November 24, 2020 Prdm1 Maf Runx2 Zeb2 Nfil3 Etv5 Litaf P R rd R R o e o rr cm pRR i a1 P P n Id2 r rd a eral 1 d m bm1 56 P Ppa Mxd1 P ou3 ro f gP u 2 O P la 2f2 nelag g Atf6 c l l 12Nu uf t2 NNr4 ip1 N rN 1r ha1Sub1 fil Np 1 5 3 N a ds 1N fk 2 b2 Zbtb32 fatc2 N Nfe fi2 cl1 Batf M Nfx aMtd c3 M y 1y cbl2 Ahr MxM d1t Mal 3x Atf4 MiM ere 1M f2e ac M ob md3 Bhlhe40 Mbd2MM M az afg Csda afLitaf Foxm1 Hmgb1 Hmgb2 Hmgb3 Ikzf3 Rorc Runx3 Tulp4 Jun Tbx21 Irf4 Irf8 Carhsp1 Crem E2f4 E2f7 E2f8 Hlx Hmga1−rs1 Irf5 Mxd3 Nfatc2 Srebf1 Srebf2 Trerf1 Whsc1 Xbp1 Cux1 Hopx Klf7 Mef2a Smad3 R Ro R sf1r re Ebf1 R c b1 nf1 R 4f 1x Elf4 P R 7ar rad Rai14 Nfat5 P mou 1 Hif1a 6f1PP oul 2ek P f1 Ets1 mh lf1 Elk3 Phf1Nupr1 Tcf4 Nr1h3N Dnajc1 fil3 Nfia E2f2 Nfat5 E2f3 Mxi1Mxd1 Eaf2 CD28SA Egr1 treated Treg Gzf1 Ikzf2 Jarid2 Klf10 Klf6 Th1 Mafg + Notc Mier1 h ligan Nfkb2 dH Plagl2 uman tDC primed CD4 1 ox p b1 abF Gm e t Gn p c9a Hd he x H p3 Hiv e b Hn f1 x Ho p Id2 Ikz f1 3 Ikzf Irf7 Irf8 Jmjd 1c Jun Klf7 Litaf Lmo2 Maf Med13l Mef2a stin e te all in Tre g Sm e tin 7 int es h1 T ma ll x vs E S h1 7 xT Tr 1E Tr1 m1 ox f2 F Fo x xk 1 Fo p2 1 oxata d 1 F 5G cm 2 13 0 24 2 6 GGmm1 3 324 20 G m114 4 81G Gm 9 Gm 4 a Gt f3 f1 Gzey1H xhe 1 rs1HHic 1a − Hifive p13 Hlx 1H ep aHiv mg mg a1 H H mgb 1 H mgb 2 H b3 4Hm g Hmg xb Hopx Hsf2 Hsf4 Id2 Ikzf2 Ikzf3 Irf1 Irf2 Irf4 Irf5 Irf8 Jarid2 Jun Junb Klf10 Klf6 Klf7 ll Resource OPEN ACCESST cells led to spontaneous weight loss over time (Figure 7A), similar to that observed in IL-10-deficient mice (Ku€hn et al., 1993). The presence of one copy of the Maf allele protected the mice from weight loss until 16 weeks of age, and one copy of Prdm1 protected the mice until at least 24 weeks of age (Fig- ure S4A). DKOmice, but not single-KO mice, had shorter colons (Figure 7B), and histological analysis of the entire intestine confirmed the presence of active colitis in DKO mice (Figure 7C; Figure S4B) with features reminiscent of human ulcerative colitis. Severe chronic active colitis with cryptitis, crypt abscess, and crypt loss with mucosal ulcers reminiscent of ulcerative colitis was themost prevalent pathology in DKOmice. DKOmice occa- sionally showed flask-shaped aphthous erosions that are com- mon in human Crohn’s disease, but other defining features of Crohn’s disease, such as transmural lymphoid aggregates, were absent in all mice (Figure 7C; Figure S4C). Although Cd4- Cre; Prdm1fl/fl mice have been reported to develop spontaneous colitis (Martins et al., 2006), we observed spontaneous intestinal disease very rarely only inmale but not in any femalemice. More- over, the pathology in thesemice wasmainly located in the prox- imal end of the small intestine rather than the colon (Figures S4D and S4E). To characterize the transcriptional changes in T cells that lead to spontaneous colitis in DKO mice, we performed scRNA-seq on CD4 T cells from the colonic lamina propria at 3 weeks of age before disease onset. We included two biological replicates for each genotype (Figure 7D) and collected a total of 13,535 high-quality single-cell profiles that were partitioned into eight distinct clusters (Figure 7E). Cluster identity was designated based on bulk RNA-seq-derived gene signatures (Immgen) and confirmed by expression of key marker genes (Figures S5A and S5B). Cells of the four genotypes distributed evenly within the naive T cell clusters (clusters 1–3), indicating negligible batch effects between samples and similar phenotypes of naive T cells in the absence of Prdm1 or Maf. However, Maf cKO and DKO cells formed distinct sub-clusters within the effector T cell cluster (cluster 4), and each of the Treg cell clusters (clusters 5–8) was dominated by a different genotype (Figures 7D–7F; Figure S5C). The proportion of effector T cells was increased in both Maf cKO and DKO (Figure 7F), but these cells were qualitatively different (Figures 7G and 7H) in that DKO effector cells had dramatically increased expression of the Th1 gene signature, which is a major pathogenic cell population implicated in IBD (Ito and Fathman, 1997; Neurath et al., 2002). The Th17 gene signature was also increased significantly in DKO but to a lesser extent (Figure 7G). A subset of effector cells in DKO mice ac- quired a signature that resembles CD4 T cells from inflamed in- testinal lesions of humans with ulcerative colitis (Smillie et al., 2019). In addition, the differentially expressed genes in DKOFigure 5. TFs Associated with IL-10 Production in Different T Helper C (A and C) TFs enriched in the IL-10+ compartments compared with their IL-10 co conditions where a direct comparison between the transcriptome of IL-10+ and I least 3 conditions were magnified. (B and D) A different display of same data in (A) and (C), respectively, showing TF expression is enriched in the IL-10+ compartment. SI, small intestine. (E) A ranking scheme (STAR Methods) for all potential regulators of IL-10, taking (Figure 5A), and enrichment in public datasets (Figure 5C).effector T cells (compared with control cells) showed unique enrichment for IBD-associated genome-wide association study (GWAS) genes that are involved in adaptive immunity (Graham and Xavier, 2020; Figure 7H). These data indicate that loss of Prdm1 and Maf leads to spontaneous colitis that resembles hu- man IBD in terms of not only pathological features but also mo- lecular signatures. Consistent with previous reports (Maynard et al., 2007), Treg cells (clusters 7 and 8) were a major source of IL-10 in the colon (Figure 7I). We observed that the average expression level of Il10 was reduced in colonic Treg cells in the absence of Maf; the average expression level and percentage of Il10-positive cells were reduced in the absence of Prdm1, and Il10 expression was barely detectable in the absence of both (Figure 7J). There- fore, Prdm1 and Maf were also required for Il10 expression in Treg cells in vivo. Besides downregulation of Il10, DKO Treg cells, compared with single-KO or control Treg cells, exhibited a unique gene expression profile (cluster 5; Figures 7D–7F). DKO Treg cells lost immunoregulatory phenotypes, including expression of TFs critical for Treg cell stability and function (e.g., Ikzf2 and Gata3), co-stimulatory receptors (e.g., Cd28, Tnfrsf18, and Tnfrsf4), and soluble immunosuppressive molecules (e.g., Areg and Apoe). On the other hand, DKO Treg cells acquired Th1- associated (e.g., Nkg7, Xcl1, Lta, and Cxcl10) and Cytotoxic T Lymphocytes (CTL)-associated (e.g., Cd160 and Gpr18) genes that are known to actively promote inflammation. Moreover, DKO Treg cells showed profound changes in their chemotaxis profile, turning off Ccr2 and Cxcr6 while dramatically upregulat- ing Ccr7 (Figure 7K). These data indicated that Prdm1 and Maf cooperatively regulate the identity and function of Treg cells and are indispensable for immune tolerance in vivo. DISCUSSION Computational inference of gene regulation from temporal profiling of gene expression has shown great potential to delin- eate the dynamic transcriptional circuits that regulate T cell dif- ferentiation. We and others have successfully built models of regulatory networks for Th17 cells (Wu et al., 2013; Yosef et al., 2013; Ciofani et al., 2012) and Th2 cells (Henriksson et al., 2019), discovering key regulators and revealing general principles governing T cell differentiation. Here we computed a transcriptional network induced by IL-27 in CD4 T cells that showed strong predicative power for identification of Il10 regula- tors: 18 (75%) of the 24 predicted TFs we validated experimen- tally were confirmed to be regulating Il10 expression. In addition to IL-10, IL-27-induced Tr1 cells feature expression of IFN-g (Awasthi et al., 2007; Pot et al., 2009) and co-inhibitory receptorsells mpartments in (A) in-vitro-generated T helper cell subsets, (C) 10 in vivo/ex vivo L-10 cells was made in public data (Table S1). TFs that are enriched under at s that are enriched under at least 3 conditions and the conditions where their into account network centrality (Figure 3B), enrichment in in vitro conditions Cell Reports 33, 108433, November 24, 2020 9 ll OPEN ACCESS Resource A Prdm1 Maf 3 4 3 2 2 1 1 0 0 Th1 Th2 Th17 Tr1 Treg Th1 Th2 Th17 Tr1 Treg B CNS-9 Promoter HSS 2.98 HSS 6.45 [0 – 2399] 5 kb Maf ChIP [0 – 14] Prdm1 ChIP [0 – 33] ATAC-seq Tr1 Il10 C Promoter CNS-9 HSS 2.98 HSS 6.45 D Th1 Th2 6 15 *** 40 * 5 NS NS 4 ** 3010 * 3 Prdm1 20 2 5 1 10 0 0 0 6 Th17 Tr1 5 20 * 15 **** 4 15 NS **3 Maf NS 10 NS 2 10 1 5 5 0 0 25 50 100 0 25 50 100 0 25 50 100 0 25 50 100 (ng) (ng) (ng) (ng) 0 0 l f f Treg tro 1 m aM aM 5 NS 6 *** 8 *** n d8 **** r 8 *** ** C o P +1 4 m 4 **** 6 **** 6 **** 6 dPr 3 * ** 4 NS 4 **** Combination 4 * 2 2 ** 1 2 2 2 0 0 0 0 0 ol 1 af af ol 1 af af lr r ro 1 f f l 1 f f l 1 f f nt dm M M nt dm M M nt dm a a M M tr o n dm a a tro m a a o Pr + o r M M + o n d M M C 1 C P 1 C P r + o r1 C P 1 + rCo P 1 + dm dm dm dm m Pr Pr Pr Pr Pr d Figure 6. Prdm1 and Maf Synergistically Regulate IL-10 in All T Helper Cells (A) Enrichment of Prdm1 and Maf mRNA in in-vitro-generated T helper cells validated by qPCR. (B) ChIP-seq of Maf in Th17 cells and Prdm1 in tissue-resident memory T cells aligned with ATAC-seq data of Tr1 cells differentiated in vitro at 72 h. (C) Luciferase activity in 293T cells transfected with Il10 luciferase reporters along with constructs encoding Prdm1, Maf, or both. n = 3. (D) T helper cells differentiated in vitro were transduced with two retroviruses expressing Prdm1 andMaf, respectively. IL-10 expression in control cells, Prdm1- overexpressing cells, Maf-overexpressing cells, and cells overexpressing Prdm1 and Maf was measured by flow cytometry 48 h after transduction. RLU RLU RLU Log2 (IL-10+ / IL-10–) Log2 (IL-10+ / IL-10–) IL-10+ /CD4+ (%) IL-10+ /CD4+ (%) IL-10+ /CD4+ (%)(Chihara et al., 2018; DeLong et al., 2019). Therefore, the pre- dicted TFs in the IL-27 network presented here could also be uti- lized for defining the transcriptional regulation of these mole- cules in a manner similar to what is presented here for Il10. By genetically perturbing the IL-27 network, we identified crit- ical regulators of Il10, which may shed light on previously unap- preciated roles of IL-10 in physiological processes and deepen our understanding of IL-10-related immune disorders such as IBD (Zhu et al., 2017). For example, Atf3 is a TF that is induced10 Cell Reports 33, 108433, November 24, 2020by endoplasmic reticulum stress (Schmitz et al., 2018) with anti-inflammatory properties (De Nardo et al., 2014; Gilchrist et al., 2006); induction of IL-10 by Atf3 may provide a negative feedback loop to dampen endoplasmic reticulum (ER) stress (Hasnain et al., 2013; Shkoda et al., 2007) and suppress inflam- mation. Further, Fosl2 is a member of the AP1 family, which con- tains several members that were implicated in Il10 regulation (Hu et al., 2006; Kremer et al., 2007). Fosl2 has been shown previ- ously to regulate the pathogenicity of Th17 cells (Ciofani et al., ll Resource OPEN ACCESS A B Control (Cre–) Maf cKO Control Maf Prdm1 Colon(Cre–) cKO cKO DKO 10 Prdm1 cKO DKO NS 25 9 NS 20 8 p < 0.0001 **** 7 15 6 10 5 5 – )e KO O O Cr( f c c K DK ol a 1 0 tr M m on d Pr C 30 C Control (Cre–) Prdm1 cKO Maf cKO DKO25 20 p < 0.0001 15 5x 10 5 0 0 4 8 12 20x Age (wk) D Control 1 Maf cKO 1 E 1: Naïve CD4 5: Treg 1: Naïve CD4 4: Teff 7: TregControl 2 Maf cKO 2 F2: Naïve CD4 6: Treg 2: Naïve CD4 5: Treg 8: Proliferative Treg Prdm1 cKO 1 DKO 1 3: Naïve CD4 7: Treg 3: Naïve CD4 6: Treg Prdm1 cKO 2 DKO 2 4: Teff 8: Proliferative Treg 100 3 3 6 3 80 7 2 60 0 0 1 5 40 –3 –3 4 8 20 –6 –6 0 –10 –5 0 5 10 –10 –5 0 5 10 1 2 1 2 1 2 1 2 UMAP 1 UMAP 1 Control Prdm1 Maf DKO cKO cKO G Th1 signature Th17 signature H UC CD4 T cell signature IBD GWAS genes I Il10 –16 (Smillie et al. 2020) (Graham et al. 2020)p < 2.2 × 10 p < 2.2 × 10–16 p < 2.2 × 10–16 p < 2.2 × 10–16 p = 0.0004 p = 4.2 × 10–12 NS 0.2 2.0 4 NS NS 0.1 * 0.5 1.5 3 0.1 0.0 1.0 2 0.0 0.0 0.5 1 –0.1 –0.1 0 0.0 l l l 1 2 3 4 5 6 7 8 tro KO KO KO tro KOn c c D n c cK O KOD nt ro cK O KO O O O O o f o f o f c D K cK cK DK Cluster C rd m a M C d m a r M C d m a m af P P Pr M d Pr M J Il10 K DKO DKO 4 Maf cKO Percent 3 Maf cKO Percent expressed expressed 10 25 20 50 2 Prdm1 cKO 30 Prdm1 cKO 75 Average Average expression 1 expression 1.0 1.0 Control 0.5 Control 0.5 0.0 0.0 –0.5 0 –0.5 –1.0 Il10 ltro KO KO KO g 7 cl1 tak X L cl1 0 60 18 7 e 7 2 31 r cr ga d zf ta d2 8 8 4 g e 0 6 f1 rs f re po Il1 cr 2 cr on c f c D N d p C It C Ik a Cx C G G C f rs nf A A C Cx C dm ar M T n T P (legend on next page) Cell Reports 33, 108433, November 24, 2020 11 Score UMAP 2 Body weight (g) Body weight (g) Expression level UMAP 2 Score –log10(p-value) Length (cm) Proportion (%) Expression level ll OPEN ACCESS Resource2012), which play an important role in the pathogenesis of IBD. A single-nucleotide polymorphism (SNP) in Fosl2 (rs925255) has been linked genetically to IBD in a GWAS (Jostins et al., 2012). Our study raises the possibility that the SNP in Fosl2may further influence susceptibility to IBD by regulating IL-10 expression. Last, we identified Hlx as a regulator of IL-10 and showed that its haplodeficiency is sufficient to convert Tr1 cells to proinflam- matory cells that exacerbate T cell transfer colitis. Interestingly, theHlx locus has been shown to be hypermethylated in epithelial cells in humans with IBD, and these data suggest that Hlx might have a role in regulating immune responses beyond T cells. The lineage-defining TFs for Th2 (GATA-3) and Th17 (ROR-gt) have been shown to contribute to IL-10 expression (Shoemaker et al., 2006; Wang et al., 2015). However, the role of T-bet, the master TF for Th1 cells, in Il10 regulation has been controversial. One study has reported that IL-10 production is increased in CD4 T cells in the absence of T-bet (Shin et al., 2014), which could be due to the indirect effect of a decrease in IFN-g (Hu et al., 2006). Other studies have reported that T-bet can induce IL-10 produc- tion but under conditions where T-bet or other TFs are overex- pressed (Rutz et al., 2008; Zhu et al., 2015). Here we show that genetic deficiency in T-bet leads to impaired IL-10 production in Tr1 cells. Additionally, we show, by ChIP-seq and luciferase assays, that T-bet can directly bind and transactivate Il10. Thus, the master TFs for all T helper cell subsets can induce immunoregulatory genes to mitigate overexuberant responses. Eomes, another T-box TF that is highly homologous to T-bet in its DNA binding domain (Pearce et al., 2003), has been reported to regulate IL-10 in a GVHDmodel (Zhang et al., 2017). Our study suggests that the relative contribution of these two TFs to IL-10 regulation may be highly context dependent (Zhang et al., 2017). Master TFs have been identified for other T cell subsets but not for Tr1 cells. Our network analysis in Tr1 cells highlighted Prdm1 and Maf as central hubs in regulating Il10. Not only are they heavily regulated, but, more importantly, they orchestrate a reg- ulatory circuit composed of multiple other transcriptional modu- lators. Prdm1/Maf DKO Tr1 cells, but not either single KO Tr1 cells, exhibited complete loss of Il10 and collapse of the Il10 reg- ulatory circuit, both accompanied by reduced chromatin acces- sibility, and a notable upregulation of the Il10 repressor Bhlhe40. Expression of co-inhibitory receptors, another hallmark of Tr1Figure 7. Genetic Deficiency of Prdm1 and Maf, but Not Either Alone, Unique Cluster of Treg Cells (A) Weekly monitored body weights. Top: female mice. Bottom: male mice. n R (B) Colon length of the indicated mice, presented as seen by gross anatomy and (C) Hematoxylin and eosin staining of colon Swiss rolls. Pictures are representative 250 mm. (D–K) CD4 T cells from colonic lamina propria were profiled by scRNA-seq. (D and E) Uniform manifold approximation and projection (UMAP) plots show 13 (F) Distribution of cells with different genotypes in clusters. (G and H) Left: distribution of gene signature scores of Tconv cells (clusters 1–4 GWAS genes that are involved in adaptive immunity in differentially expressed gen the control. Significance of enrichment was tested by hypergeometric test. (I-K) Gene expression level represented as log(TP10K+1). (I) Il10 expression by control (WT) cells across clusters. (J) Il10 expression by Treg cells (clusters 5–8) across genotypes. (K) Representative differentially expressed genes of DKO Treg cells compared wit express the gene; color indicates mean expression in expressing cells relative to 12 Cell Reports 33, 108433, November 24, 2020cells (Brockmann et al., 2018; Chihara et al., 2018; DeLong et al., 2019), are induced by IL-27 and controlled by Prdm1 and Maf transcriptionally and at the chromatin level. These data suggest that the key signature of Tr1 cells might be estab- lished through collaboration between two TFs with complemen- tary roles. We and others have shown that c-Maf is a universal regulator of IL-10 in Th1, Th2, Th17, Tr1, aswell as Treg cells (Gabrysová et al., 2018). Further, we discovered that Maf needs to cooperate with other TFs, such as Ahr, to achieve robust Il10 transcription (Ape- toh et al., 2010). In this study, we identified Prdm1 as a critical partner ofMaf and that together they synergistically transactivate Il10 in all CD4 T cell subsets, including IL-10-producing Tr1 cells. Commitment of T helper cells to specific subsets requires in- duction of master TFs that not only induce specific transcrip- tional programs that push T cell subsets in one direction but also initiate repressive programs that antagonize other fates (Sungnak et al., 2019). Interestingly, we observed that, although Prdm1 and Maf synergistically promote IL-10 production, they do not inhibit production of signature cytokines of the different T helper cell subsets, enabling them to co-produce IL-10 while maintaining their original transcriptional program. We found that Prdm1/Maf DKO mice, but not single KO mice, phenocopy Il10-deficient mice and develop spontaneous colitis that presents pathological andmolecular features of human IBD. Prdm1 is a well-recognized GWAS gene associated with IBD (El- linghaus et al., 2013). It would therefore be interesting to investi- gate whether SNPs related to Maf can further enhance IBD sus- ceptibility. With scRNA-seq analysis, we discovered a unique cluster of colonic Treg cells in Prdm1/Maf DKO mice that was not observed when Prdm1 (Cretney et al., 2011; Garg et al., 2019; Ogawa et al., 2018) or Maf (Neumann et al., 2019; Xu et al., 2018) was perturbed individually. These DKO Treg cells lose immunoregulatory phenotypes, including production of IL- 10, and acquire strong Th1- and CTL-associated gene signa- tures, indicating potential to actively exacerbate inflammation. In addition, this DKO Treg cell cluster shows a profound shift in the use of chemokine receptors from those that drive T cells to tissue with active inflammation (e.g., Ccr2 and Cxc6) (Hamano et al., 2014; Loyher et al., 2016; Mondini et al., 2019; Zhang et al., 2009) to Ccr7, which, together with two other markersin T Cells Leads to Human IBD-like Spontaneous Colitis Driven by a 8. Data are represented as mean ± SD. measurement. of 10 control, 4 Prdm1 cKO, 6Maf cKO, and 7DKOmice. Scale bars represent ,535 cells (dots) colored by genotype (D) or cluster (E). ) by genotype. ‘‘+’’ indicates median. (H) right: enrichment of IBD-associated es of Prdm1 cKO,Maf cKO, and DKO Tconv cells, respectively, compared with h all other genotypes. Dot size represents the fraction of cells in the cluster that other genotypes. ll Resource OPEN ACCESShighly expressed by DKO Treg cells, Lta (Upadhyay and Fu, 2013) and Itgae (Leithäuser et al., 2006), are associated with development of lymphoid-like structures. Therefore, it would be interesting to further study how Prdm1 and Maf regulate the migration and location of Treg cells. We have shown that Prdm1 andMaf co-operatively induce the co-inhibitory receptor gene module on exhausted CD8 T cells (Chihara et al., 2018), which not only have a dysfunctional effector program but also co-produce IL-10 to actively suppress the immune responses in chronic viral infections and cancer. Further, Maf was also implicated in IL-10 expression in B cells (Liu et al., 2018) and macrophages (Cao et al., 2005), and Prdm1 has a regulatory role in dendritic cells (Kim et al., 2011; Watchmaker et al., 2014). These data, together with our current study, emphasize the importance of cooperativity between Prdm1 and Maf in regulating immunoregulatory gene programs across multiple immune cell types. STAR+METHODS Detailed methods are provided in the online version of this paper and include the following: d KEY RESOURCES TABLE d RESOURCE AVAILABILITYB Lead Contact B Materials Availability B Data and Code Availability d EXPERIMENTAL MODEL AND SUBJECT DETAILS B Mice and Ethics Statement d METHOD DETAILS B Experimental methods B Computational Methods d QUANTIFICATION AND THE STATISTICAL ANALYSIS SUPPLEMENTAL INFORMATION Supplemental Information can be found online at https://doi.org/10.1016/j. celrep.2020.108433. ACKNOWLEDGMENTS The authors thank Christophe Benoist, Arlene Sharpe, Mikael Pittet, Mary Collins, andKaren Dixon for constructive criticism anddiscussions andDeneen Kozoriz, Rajesh K. Krishnan, Leslie Gaffney, Sarah Zaghouani, Haoxin Li, Rui- han Tang, Qianxia Zhang, Yu Hou, Jingwen Shi, Danyang He, Sheng Xiao, and Ido Amit for technical assistance. This work was supported by NIH grants R01NS30843, R01AI144166, P01AI073748, P01AI039671, P01AI056299, and P01AI129880 (to V.K.K.) and the Klarman Cell Observatory (to A.R.). A.R. is an Investigator of the Howard Hughes Medical Institute. A.C.A. is a recipient of the Brigham and Women’s President’s Scholar Award and is supported by NIH grant CA229400. A.M. was supported by the Alon Fellowship for Outstanding Young Scientists, Israel Council for Higher Education. L.A. was supported by the European Research Council (grant agreement 677251). A.A. was supported by DST-SERB grant CRG/2018/002653 from the Depart- ment of Science and Technology, Government of India. AUTHOR CONTRIBUTIONS V.K.K. and A.R. conceived the study. H.Z., A.M., N.Y., N.C., C.W., L.A., A.R., and V.K.K. designed experiments and interpreted results. H.Z., N.C., A.A.,C.P., and L.A. performed and analyzed experiments with assistance from Y.E., A.L., H.S., J.X., K.K., and N.A. A.M., N.Y., and C.L. analyzed bulk RNA- seq and performed network analyses. H.Z. and C.L. analyzed scRNA-seq and ATAC-seq. J.N., E.C., P.I.T., A. Schnell, and H.Z. performed sequencing under the supervision of O.R.-R. A. Srivastava analyzed pathology. A.C.A., A.R., and V.K.K. supervised the project. H.Z. and A.M. drafted the manuscript. L.A., A.C.A., A.R., and V.K.K. edited the manuscript. DECLARATION OF INTERESTS A.R. is a founder and equity holder of Celsius Therapeutics, an equity holder in Immunitas Therapeutics, and, until August 31, 2020, an SAB member of Syros Pharmaceuticals, Neogene Therapeutics, Asimov, and Thermo Fisher Scienti- fic. From August 1, 2020, A.R. is an employee of Genentech, a member of the Roche Group. V.K.K. has an ownership interest in Tizona Therapeutics, Celsius Therapeutics, and Bicara Therapeutics. V.K.K. has financial interests in Biocon Biologic, BioLegend, Elpiscience Biopharmaceutical Ltd., Equilium Inc., and Syngene Intl. V.K.K. is a member of SABs for Elpiscience Biopharma- ceutical Ltd., GSK, Kintai Therapeutics, Repertoir Immune Medicines, Rubius Therapeutics, and Tizona Therapeutics. A.C.A. is a member of SAB for Tizona Therapeutics, Compass Therapeutics, Zumutor Biologics, ImmuneOncia, and Astellas Global Pharma Development Inc. A.C.A.’s and V.K.K.’s interests were reviewed and managed by the Brigham and Women’s Hospital and Partners Healthcare and A.R.’s interests by the Broad Institute and HHMI in accordance with their conflict of interest policies. Received: March 4, 2020 Revised: July 14, 2020 Accepted: November 4, 2020 Published: November 24, 2020 REFERENCES Anders, S., and Huber,W. (2010). Differential expression analysis for sequence count data. Genome Biol. 11, R106. Apetoh, L., Quintana, F.J., Pot, C., Joller, N., Xiao, S., Kumar, D., Burns, E.J., Sherr, D.H., Weiner, H.L., and Kuchroo, V.K. (2010). The aryl hydrocarbon re- ceptor interacts with c-Maf to promote the differentiation of type 1 regulatory T cells induced by IL-27. Nat. Immunol. 11, 854–861. Artis, D., Villarino, A., Silverman, M., He, W., Thornton, E.M., Mu, S., Summer, S., Covey, T.M., Huang, E., Yoshida, H., et al. (2004). The IL-27 receptor (WSX- 1) is an inhibitor of innate and adaptive elements of type 2 immunity. J. Immunol. 173, 5626–5634. Awasthi, A., Carrier, Y., Peron, J.P.S., Bettelli, E., Kamanaka, M., Flavell, R.A., Kuchroo, V.K., Oukka, M., and Weiner, H.L. (2007). A dominant function for interleukin 27 in generating interleukin 10-producing anti-inflammatory T cells. Nat. Immunol. 8, 1380–1389. Batten, M., Li, J., Yi, S., Kljavin, N.M., Danilenko, D.M., Lucas, S., Lee, J., de Sauvage, F.J., and Ghilardi, N. (2006). Interleukin 27 limits autoimmune encephalomyelitis by suppressing the development of interleukin 17-produc- ing T cells. Nat. Immunol. 7, 929–936. Batten, M., Kljavin, N.M., Li, J., Walter, M.J., de Sauvage, F.J., and Ghilardi, N. (2008). Cutting edge: IL-27 is a potent inducer of IL-10 but not FoxP3 in murine T cells. J. Immunol. 180, 2752–2756. Bettelli, E., Carrier, Y., Gao, W., Korn, T., Strom, T.B., Oukka, M., Weiner, H.L., and Kuchroo, V.K. (2006). Reciprocal developmental pathways for the gener- ation of pathogenic effector TH17 and regulatory T cells. Nature 441, 235–238. Boks, M.A., Kager-Groenland, J.R., van Ham, S.M., and ten Brinke, A. (2016). IL-10/IFNg co-expressing CD4(+) T cells induced by IL-10 DC display a regu- latory gene profile and downmodulate T cell responses. Clin. Immunol. 162, 91–99. Brockmann, L., Soukou, S., Steglich, B., Czarnewski, P., Zhao, L., Wende, S., Bedke, T., Ergen, C., Manthey, C., Agalioti, T., et al. (2018). Molecular and functional heterogeneity of IL-10-producing CD4+ T cells. Nat. Commun. 9, 5457.Cell Reports 33, 108433, November 24, 2020 13 ll OPEN ACCESS ResourceBurton, B.R., Britton, G.J., Fang, H., Verhagen, J., Smithers, B., Sabatos-Pey- ton, C.A., Carney, L.J., Gough, J., Strobel, S., andWraith, D.C. (2014). Sequen- tial transcriptional changes dictate safe and effective antigen-specific immu- notherapy. Nat. Commun. 5, 4741. Butler, A., Hoffman, P., Smibert, P., Papalexi, E., and Satija, R. (2018). Inte- grating single-cell transcriptomic data across different conditions, technolo- gies, and species. Nat. Biotechnol. 36, 411–420. Cao, S., Liu, J., Song, L., and Ma, X. (2005). The protooncogene c-Maf is an essential transcription factor for IL-10 gene expression in macrophages. J. Immunol. 174, 3484–3492. Chan, K., Lu, R., Chang, J.C., and Kan, Y.W. (1996). NRF2, a member of the NFE2 family of transcription factors, is not essential for murine erythropoiesis, growth, and development. Proc. Natl. Acad. Sci. USA 93, 13943–13948. Chechik, G., and Koller, D. (2009). Timing of gene expression responses to environmental changes. J. Comput. Biol. 16, 279–290. Chihara, N.,Madi, A., Kondo, T., Zhang, H., Acharya, N., Singer, M., Nyman, J., Marjanovic, N.D., Kowalczyk, M.S., Wang, C., et al. (2018). Induction and tran- scriptional regulation of the co-inhibitory gene module in T cells. Nature 558, 454–459. Ciofani, M., Madar, A., Galan, C., Sellars, M., Mace, K., Pauli, F., Agarwal, A., Huang, W., Parkhurst, C.N., Muratet, M., et al. (2012). A validated regulatory network for Th17 cell specification. Cell 151, 289–303. Corces, M.R., Buenrostro, J.D., Wu, B., Greenside, P.G., Chan, S.M., Koenig, J.L., Snyder, M.P., Pritchard, J.K., Kundaje, A., Greenleaf, W.J., et al. (2016). Lineage-specific and single-cell chromatin accessibility charts human hema- topoiesis and leukemia evolution. Nat. Genet. 48, 1193–1203. Cretney, E., Xin, A., Shi, W., Minnich, M., Masson, F., Miasari, M., Belz, G.T., Smyth, G.K., Busslinger, M., Nutt, S.L., and Kallies, A. (2011). The transcription factors Blimp-1 and IRF4 jointly control the differentiation and function of effector regulatory T cells. Nat. Immunol. 12, 304–311. De Nardo, D., Labzin, L.I., Kono, H., Seki, R., Schmidt, S.V., Beyer, M., Xu, D., Zimmer, S., Lahrmann, C., Schildberg, F.A., et al. (2014). High-density lipopro- tein mediates anti-inflammatory reprogramming of macrophages via the tran- scriptional regulator ATF3. Nat. Immunol. 15, 152–160. DeLong, J.H., O’Hara Hall, A., Rausch, M., Moodley, D., Perry, J., Park, J., Phan, A.T., Beiting, D.P., Kedl, R.M., Hill, J.A., et al. (2019). IL-27 and TCR Stimulation Promote T Cell Expression of Multiple Inhibitory Receptors. Immu- nohorizons 3, 13–25. Ellinghaus, D., Zhang, H., Zeissig, S., Lipinski, S., Till, A., Jiang, T., Stade, B., Bromberg, Y., Ellinghaus, E., Keller, A., et al. (2013). Association between var- iants of PRDM1 and NDP52 and Crohn’s disease, based on exome sequencing and functional studies. Gastroenterology 145, 339–347. Feng, J., Wang, H., Shin, D.-M., Masiuk, M., Qi, C.-F., and Morse, H.C., 3rd. (2011). IFN regulatory factor 8 restricts the size of the marginal zone and follic- ular B cell pools. J. Immunol. 186, 1458–1466. Finak, G., McDavid, A., Yajima, M., Deng, J., Gersuk, V., Shalek, A.K., and Linsley, P.S. (2015). MAST: a flexible statistical framework for assessing tran- scriptional changes and characterizing heterogeneity in single-cell RNA sequencing data. Genome Biol. 16, 1–13. Finotto, S., Neurath, M.F., Glickman, J.N., Qin, S., Lehr, H.A., Green, F.H.Y., Ackerman, K., Haley, K., Galle, P.R., Szabo, S.J., et al. (2002). Development of spontaneous airway changes consistent with human asthma in mice lacking T-bet. Science 295, 336–338. Fitzgerald, D.C., Zhang, G.-X., El-Behi, M., Fonseca-Kelly, Z., Li, H., Yu, S., Saris, C.J.M., Gran, B., Ciric, B., and Rostami, A. (2007). Suppression of auto- immune inflammation of the central nervous system by interleukin 10 secreted by interleukin 27-stimulated T cells. Nat. Immunol. 8, 1372–1379. Gabrysová, L., Howes, A., Saraiva, M., and O’Garra, A. (2014). The regulation of IL-10 expression. Curr. Top. Microbiol. Immunol. 380, 157–190. Gabrysová, L., Alvarez-Martinez, M., Luisier, R., Cox, L.S., Sodenkamp, J., Hosking, C., Pérez-Mazliah, D., Whicher, C., Kannan, Y., Potempa, K., et al. (2018). c-Maf controls immune responses by regulating disease-specific gene networks and repressing IL-2 in CD4+ T cells. Nat. Immunol. 19, 497–507.14 Cell Reports 33, 108433, November 24, 2020Gagliani, N., Amezcua Vesely, M.C., Iseppon, A., Brockmann, L., Xu, H., Palm, N.W., de Zoete, M.R., Licona-Limón, P., Paiva, R.S., Ching, T., et al. (2015). Th17 cells transdifferentiate into regulatory T cells during resolution of inflam- mation. Nature 523, 221–225. Garber, M., Yosef, N., Goren, A., Raychowdhury, R., Thielke, A., Guttman, M., Robinson, J., Minie, B., Chevrier, N., Itzhaki, Z., et al. (2012). A high-throughput chromatin immunoprecipitation approach reveals principles of dynamic gene regulation in mammals. Mol. Cell 47, 810–822. Garg, G., Muschaweckh, A., Moreno, H., Vasanthakumar, A., Floess, S., Lep- ennetier, G., Oellinger, R., Zhan, Y., Regen, T., Hiltensperger, M., et al. (2019). Blimp1 prevents methylation of foxp3 and loss of regulatory T cell identity at sites of inflammation. Cell Rep. 26, 1854–1868.e5. Gascoyne, D.M., Long, E., Veiga-Fernandes, H., de Boer, J., Williams, O., Sed- don, B., Coles, M., Kioussis, D., and Brady, H.J.M. (2009). The basic leucine zipper transcription factor E4BP4 is essential for natural killer cell develop- ment. Nat. Immunol. 10, 1118–1124. Gilchrist, M., Thorsson, V., Li, B., Rust, A.G., Korb, M., Roach, J.C., Kennedy, K., Hai, T., Bolouri, H., and Aderem, A. (2006). Systems biology approaches identify ATF3 as a negative regulator of Toll-like receptor 4. Nature 441, 173–178. Graham, D.B., and Xavier, R.J. (2020). Pathway paradigms revealed from the genetics of inflammatory bowel disease. Nature 578, 527–539. Hall, A.O., Beiting, D.P., Tato, C., John, B., Oldenhove, G., Lombana, C.G., Pritchard, G.H., Silver, J.S., Bouladoux, N., Stumhofer, J.S., et al. (2012). The cytokines interleukin 27 and interferon-g promote distinct Treg cell popu- lations required to limit infection-induced pathology. Immunity 37, 511–523. Hamano, R., Baba, T., Sasaki, S., Tomaru, U., Ishizu, A., Kawano, M., Yama- gishi, M., and Mukaida, N. (2014). Ag and IL-2 immune complexes efficiently expand Ag-specific Treg cells that migrate in response to chemokines and reduce localized immune responses. Eur. J. Immunol. 44, 1005–1015. Hasnain, S.Z., Tauro, S., Das, I., Tong, H., Chen, A.C.-H., Jeffery, P.L., McDo- nald, V., Florin, T.H., andMcGuckin, M.A. (2013). IL-10 promotes production of intestinal mucus by suppressing proteinmisfolding and endoplasmic reticulum stress in goblet cells. Gastroenterology 144, 357–368.e9. Hedrich, C.M., and Bream, J.H. (2010). Cell type-specific regulation of IL-10 expression in inflammation and disease. Immunol. Res. 47, 185–206. Hennet, T., Hagen, F.K., Tabak, L.A., and Marth, J.D. (1995). T-cell-specific deletion of a polypeptide N-acetylgalactosaminyl-transferase gene by site- directed recombination. Proc. Natl. Acad. Sci. USA 92, 12070–12074. Henriksson, J., Chen, X., Gomes, T., Ullah, U., Meyer, K.B., Miragaia, R., Duddy, G., Pramanik, J., Yusa, K., Lahesmaa, R., and Teichmann, S.A. (2019). Genome-wide CRISPR Screens in T Helper Cells Reveal Pervasive Crosstalk between Activation and Differentiation. Cell 176, 882–896.e18. Hentsch, B., Lyons, I., Li, R., Hartley, L., Lints, T.J., Adams, J.M., and Harvey, R.P. (1996). Hlx homeo box gene is essential for an inductive tissue interaction that drives expansion of embryonic liver and gut. Genes Dev. 10, 70–79. Hildner, K., Edelson, B.T., Purtha, W.E., Diamond, M., Matsushita, H., Ko- hyama, M., Calderon, B., Schraml, B.U., Unanue, E.R., Diamond, M.S., et al. (2008). Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 322, 1097–1100. Hu, X., Paik, P.K., Chen, J., Yarilina, A., Kockeritz, L., Lu, T.T., Woodgett, J.R., and Ivashkiv, L.B. (2006). IFN-gamma suppresses IL-10 production and syner- gizes with TLR2 by regulating GSK3 and CREB/AP-1 proteins. Immunity 24, 563–574. Huber, S., Gagliani, N., Esplugues, E., O’Connor, W., Jr., Huber, F.J., Chaudhry, A., Kamanaka, M., Kobayashi, Y., Booth, C.J., Rudensky, A.Y., et al. (2011). Th17 cells express interleukin-10 receptor and are controlled by Foxp3 and Foxp3+ regulatory CD4+ T cells in an interleukin-10-dependent manner. Immunity 34, 554–565. Huynh, J.P., Lin, C.-C., Kimmey, J.M., Jarjour, N.N., Schwarzkopf, E.A., Brad- street, T.R., Shchukina, I., Shpynov, O., Weaver, C.T., Taneja, R., et al. (2018). Bhlhe40 is an essential repressor of IL-10 during Mycobacterium tuberculosis infection. J. Exp. Med. 215, 1823–1838. ll Resource OPEN ACCESSIto, H., and Fathman, C.G. (1997). CD45RBhigh CD4+ T cells from IFN-gamma knockout mice do not induce wasting disease. J. Autoimmun. 10, 455–459. Iyer, S.S., and Cheng, G. (2012). Role of interleukin 10 transcriptional regula- tion in inflammation and autoimmune disease. Crit. Rev. Immunol. 32, 23–63. Jiang, X., Tian, F., Du, Y., Copeland, N.G., Jenkins, N.A., Tessarollo, L., Wu, X., Pan, H., Hu, X.-Z., Xu, K., et al. (2008). BHLHB2 controls Bdnf promoter 4 ac- tivity and neuronal excitability. J. Neurosci. 28, 1118–1130. Jostins, L., Ripke, S., Weersma, R.K., Duerr, R.H., McGovern, D.P., Hui, K.Y., Lee, J.C., Schumm, L.P., Sharma, Y., Anderson, C.A., et al.; International IBD Genetics Consortium (IIBDGC) (2012). Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease. Nature 491, 119–124. Kamanaka, M., Kim, S.T., Wan, Y.Y., Sutterwala, F.S., Lara-Tejero, M., Galán, J.E., Harhaj, E., and Flavell, R.A. (2006). Expression of interleukin-10 in intes- tinal lymphocytes detected by an interleukin-10 reporter knockin tiger mouse. Immunity 25, 941–952. Kaplan, M.H., Sun, Y.L., Hoey, T., and Grusby, M.J. (1996). Impaired IL-12 re- sponses and enhanced development of Th2 cells in Stat4-deficient mice. Na- ture 382, 174–177. Karreth, F., Hoebertz, A., Scheuch, H., Eferl, R., and Wagner, E.F. (2004). The AP1 transcription factor Fra2 is required for efficient cartilage development. Development 131, 5717–5725. Karwacz, K., Miraldi, E.R., Pokrovskii, M., Madi, A., Yosef, N., Wortman, I., Chen, X., Watters, A., Carriero, N., Awasthi, A., et al. (2017). Critical role of IRF1 and BATF in forming chromatin landscape during type 1 regulatory cell differentiation. Nat. Immunol. 18, 412–421. Kim, S.J., Zou, Y.R., Goldstein, J., Reizis, B., and Diamond, B. (2011). Tolero- genic function of Blimp-1 in dendritic cells. J. Exp. Med. 208, 2193–2199. Klein, U., Casola, S., Cattoretti, G., Shen, Q., Lia, M., Mo, T., Ludwig, T., Ra- jewsky, K., and Dalla-Favera, R. (2006). Transcription factor IRF4 controls plasma cell differentiation and class-switch recombination. Nat. Immunol. 7, 773–782. Kremer, K.N., Kumar, A., and Hedin, K.E. (2007). Haplotype-independent cos- timulation of IL-10 secretion by SDF-1/CXCL12 proceeds via AP-1 binding to the human IL-10 promoter. J. Immunol. 178, 1581–1588. Ku€hn, R., Löhler, J., Rennick, D., Rajewsky, K., and Mu€ller, W. (1993). Inter- leukin-10-deficient mice develop chronic enterocolitis. Cell 75, 263–274. Langenhorst, D., Gogishvili, T., Ribechini, E., Kneitz, S., McPherson, K., Lutz, M.B., and Hu€nig, T. (2012). Sequential induction of effector function, tissue migration and cell death during polyclonal activation of mouse regulatory T- cells. PLoS ONE 7, e50080. Lee, J., Christoforo, G., Foo, C.S., Probert, C., Kundaje, A., Boley, N., koh- pangwei, Dacre, M., and Kim, D. (2016). kundajelab/atac_ dnase_pipelines: 0.3.3. https://doi.org/10.5281/zenodo.211733. Lee, P.P., Fitzpatrick, D.R., Beard, C., Jessup, H.K., Lehar, S., Makar, K.W., Pérez-Melgosa, M., Sweetser, M.T., Schlissel, M.S., Nguyen, S., et al. (2001). A critical role for Dnmt1 and DNA methylation in T cell development, function, and survival. Immunity 15, 763–774. Lee, C.-G., Kang, K.-H., So, J.-S., Kwon, H.-K., Son, J.-S., Song, M.-K., Sa- hoo, A., Yi, H.-J., Hwang, K.-C., Matsuyama, T., et al. (2009). A distal cis-reg- ulatory element, CNS-9, controls NFAT1 and IRF4-mediated IL-10 gene acti- vation in T helper cells. Mol. Immunol. 46, 613–621. Lee, C.-G., Kwon, H.-K., Sahoo, A., Hwang, W., So, J.-S., Hwang, J.-S., Chae, C.-S., Kim, G.-C., Kim, J.-E., So, H.-S., et al. (2012). Interaction of Ets-1 with HDAC1 represses IL-10 expression in Th1 cells. J. Immunol. 188, 2244–2253. Leek, J.T., Monsen, E., Dabney, A.R., and Storey, J.D. (2006). EDGE: extrac- tion and analysis of differential gene expression. Bioinformatics 22, 507–508. Leithäuser, F., Meinhardt-Krajina, T., Fink, K., Wotschke, B., Möller, P., and Reimann, J. (2006). Foxp3-expressing CD103+ regulatory T cells accumulate in dendritic cell aggregates of the colonic mucosa in murine transfer colitis. Am. J. Pathol. 168, 1898–1909. Leonard, W.J., and Wan, C.-K. (2016). IL-21 Signaling in Immunity. F1000Res. 5, 224.Lewandoski, M., Meyers, E.N., and Martin, G.R. (1997). Analysis of Fgf8 gene function in vertebrate development. Cold Spring Harb. Symp. Quant. Biol. 62, 159–168. Li, B., and Dewey, C.N. (2011). RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome. BMC Bioinformatics 12, 323. Lin, C.-C., Bradstreet, T.R., Schwarzkopf, E.A., Sim, J., Carrero, J.A., Chou, C., Cook, L.E., Egawa, T., Taneja, R., Murphy, T.L., et al. (2014). Bhlhe40 con- trols cytokine production by T cells and is essential for pathogenicity in auto- immune neuroinflammation. Nat. Commun. 5, 3551. Liu, Y.-W., Tseng, H.-P., Chen, L.-C., Chen, B.-K., and Chang, W.-C. (2003). Functional cooperation of simian virus 40 promoter factor 1 and CCAAT/ enhancer-binding protein beta and delta in lipopolysaccharide-induced gene activation of IL-10 in mouse macrophages. J. Immunol. 171, 821–828. Liu, M., Zhao, X., Ma, Y., Zhou, Y., Deng, M., and Ma, Y. (2018). Transcription factor c-Maf is essential for IL-10 gene expression in B cells. Scand. J. Immu- nol. 88, e12701. Love, M.I., Huber, W., and Anders, S. (2014). Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biol. 15, 550. Loyher, P.-L., Rochefort, J., Baudesson de Chanville, C., Hamon, P., Lescaille, G., Bertolus, C., Guillot-Delost, M., Krummel, M.F., Lemoine, F.M., Comba- dière, C., and Boissonnas, A. (2016). CCR2 influences T regulatory cell migra- tion to tumors and serves as a biomarker of cyclophosphamide sensitivity. Cancer Res. 76, 6483–6494. Martins, G.A., Cimmino, L., Shapiro-Shelef, M., Szabolcs, M., Herron, A., Mag- nusdottir, E., and Calame, K. (2006). Transcriptional repressor Blimp-1 regu- lates T cell homeostasis and function. Nat. Immunol. 7, 457–465. Mascanfroni, I.D., Takenaka, M.C., Yeste, A., Patel, B., Wu, Y., Kenison, J.E., Siddiqui, S., Basso, A.S., Otterbein, L.E., Pardoll, D.M., et al. (2015). Metabolic control of type 1 regulatory T cell differentiation by AHR and HIF1-a. Nat. Med. 21, 638–646. Matsuyama, T., Kimura, T., Kitagawa, M., Pfeffer, K., Kawakami, T., Wata- nabe, N., Ku€ndig, T.M., Amakawa, R., Kishihara, K., Wakeham, A., et al. (1993). Targeted disruption of IRF-1 or IRF-2 results in abnormal type I IFN gene induction and aberrant lymphocyte development. Cell 75, 83–97. Maynard, C.L., Harrington, L.E., Janowski, K.M., Oliver, J.R., Zindl, C.L., Ru- densky, A.Y., and Weaver, C.T. (2007). Regulatory T cells expressing inter- leukin 10 develop from Foxp3+ and Foxp3- precursor cells in the absence of interleukin 10. Nat. Immunol. 8, 931–941. Moh, A., Iwamoto, Y., Chai, G.-X., Zhang, S.S.-M., Kano, A., Yang, D.D., Zhang, W., Wang, J., Jacoby, J.J., Gao, B., et al. (2007). Role of STAT3 in liver regeneration: survival, DNA synthesis, inflammatory reaction and liver mass recovery. Lab. Invest. 87, 1018–1028. Mondini, M., Loyher, P.-L., Hamon, P., Gerbé de Thoré, M., Laviron, M., Ber- thelot, K., Clémenson, C., Salomon, B.L., Combadière, C., Deutsch, E., and Boissonnas, A. (2019). CCR2-Dependent Recruitment of Tregs and Mono- cytes Following Radiotherapy Is Associated with TNFa-Mediated Resistance. Cancer Immunol. Res. 7, 376–387. Montes de Oca, M., Kumar, R., de Labastida Rivera, F., Amante, F.H., Sheel, M., Faleiro, R.J., Bunn, P.T., Best, S.E., Beattie, L., Ng, S.S., et al. (2016). Blimp-1-Dependent IL-10 Production by Tr1 Cells Regulates TNF-Mediated Tissue Pathology. PLoS Pathog. 12, e1005398. Mullen, A.C., Hutchins, A.S., High, F.A., Lee, H.W., Sykes, K.J., Chodosh, L.A., and Reiner, S.L. (2002). Hlx is induced by and genetically interacts with T-bet to promote heritable T(H)1 gene induction. Nat. Immunol. 3, 652–658. Muthusamy, N., Barton, K., and Leiden, J.M. (1995). Defective activation and survival of T cells lacking the Ets-1 transcription factor. Nature 377, 639–642. Nakayamada, S., Kanno, Y., Takahashi, H., Jankovic, D., Lu, K.T., Johnson, T.A., Sun, H.W., Vahedi, G., Hakim, O., Handon, R., et al. (2011). Early Th1 cell differentiation ismarked by a Tfh cell-like transition. Immunity 35, 919–931. Neumann, C., Heinrich, F., Neumann, K., Junghans, V., Mashreghi, M.-F., Ah- lers, J., Janke, M., Rudolph, C., Mockel-Tenbrinck, N., Ku€hl, A.A., et al. (2014).Cell Reports 33, 108433, November 24, 2020 15 ll OPEN ACCESS ResourceRole of Blimp-1 in programing Th effector cells into IL-10 producers. J. Exp. Med. 211, 1807–1819. Neumann, C., Blume, J., Roy, U., Teh, P.P., Vasanthakumar, A., Beller, A., Liao, Y., Heinrich, F., Arenzana, T.L., Hackney, J.A., et al. (2019). c-Maf-depen- dent Treg cell control of intestinal TH17 cells and IgA establishes host-micro- biota homeostasis. Nat. Immunol. 20, 471–481. Neurath, M.F.,Weigmann, B., Finotto, S., Glickman, J., Nieuwenhuis, E., Iijima, H., Mizoguchi, A., Mizoguchi, E., Mudter, J., Galle, P.R., et al. (2002). The tran- scription factor T-bet regulates mucosal T cell activation in experimental colitis and Crohn’s disease. J. Exp. Med. 195, 1129–1143. Ogawa, C., Bankoti, R., Nguyen, T., Hassanzadeh-Kiabi, N., Nadeau, S., Por- ritt, R.A., Couse, M., Fan, X., Dhall, D., Eberl, G., et al. (2018). Blimp-1 Func- tions as a Molecular Switch to Prevent Inflammatory Activity in Foxp3+RORgt+ Regulatory T Cells. Cell Rep. 25, 19–28.e5. Ouyang, W., Rutz, S., Crellin, N.K., Valdez, P.A., and Hymowitz, S.G. (2011). Regulation and functions of the IL-10 family of cytokines in inflammation and disease. Annu. Rev. Immunol. 29, 71–109. Pearce, E.L., Mullen, A.C., Martins, G.A., Krawczyk, C.M., Hutchins, A.S., Ze- diak, V.P., Banica, M., DiCioccio, C.B., Gross, D.A., Mao, C.-A., et al. (2003). Control of effector CD8+ T cell function by the transcription factor Eomesoder- min. Science 302, 1041–1043. Pot, C., Jin, H., Awasthi, A., Liu, S.M., Lai, C.-Y., Madan, R., Sharpe, A.H., Karp, C.L., Miaw, S.-C., Ho, I.-C., and Kuchroo, V.K. (2009). Cutting edge: IL-27 induces the transcription factor c-Maf, cytokine IL-21, and the costimu- latory receptor ICOS that coordinately act together to promote differentiation of IL-10-producing Tr1 cells. J. Immunol. 183, 797–801. Reich, M., Liefeld, T., Gould, J., Lerner, J., Tamayo, P., and Mesirov, J.P. (2006). GenePattern 2.0. Nat. Genet. 38, 500–501. Robinson, J.T., Thorvaldsdóttir, H., Wenger, A.M., Zehir, A., and Mesirov, J.P. (2017). Variant Review with the Integrative Genomics Viewer. Cancer Res. 77, e31–e34. Roncarolo, M.G., Yssel, H., Touraine, J.L., Betuel, H., De Vries, J.E., and Spits, H. (1988). Autoreactive T cell clones specific for class I and class II HLA anti- gens isolated from a human chimera. J. Exp. Med. 167, 1523–1534. Rutz, S., Janke, M., Kassner, N., Hohnstein, T., Krueger, M., and Scheffold, A. (2008). Notch regulates IL-10 production by T helper 1 cells. Proc. Natl. Acad. Sci. USA 105, 3497–3502. Ryan, H.E., Poloni, M., McNulty, W., Elson, D., Gassmann, M., Arbeit, J.M., and Johnson, R.S. (2000). Hypoxia-inducible factor-1alpha is a positive factor in solid tumor growth. Cancer Res. 60, 4010–4015. Schmidt, J.V., Su, G.H., Reddy, J.K., Simon, M.C., and Bradfield, C.A. (1996). Characterization of a murine Ahr null allele: involvement of the Ah receptor in hepatic growth and development. Proc. Natl. Acad. Sci. USA 93, 6731–6736. Schmitz, M.L., Shaban, M.S., Albert, B.V., Gökçen, A., and Kracht, M. (2018). The Crosstalk of Endoplasmic Reticulum (ER) Stress Pathways with NF-kB: Complex Mechanisms Relevant for Cancer, Inflammation and Infection. Bio- medicines 6, 58. Schraml, B.U., Hildner, K., Ise, W., Lee, W.-L., Smith, W.A.-E., Solomon, B., Sahota, G., Sim, J., Mukasa, R., Cemerski, S., et al. (2009). The AP-1 transcrip- tion factor Batf controls T(H)17 differentiation. Nature 460, 405–409. Seillet, C., Jackson, J.T., Markey, K.A., Brady, H.J.M., Hill, G.R., Macdonald, K.P.A., Nutt, S.L., and Belz, G.T. (2013). CD8a+ DCs can be induced in the absence of transcription factors Id2, Nfil3, and Batf3. Blood 121, 1574–1583. Shapiro-Shelef, M., Lin, K.-I., McHeyzer-Williams, L.J., Liao, J., McHeyzer- Williams, M.G., and Calame, K. (2003). Blimp-1 is required for the formation of immunoglobulin secreting plasma cells and pre-plasmamemory B cells. Im- munity 19, 607–620. Shim, J.O. (2019). Recent advance in very early onset inflammatory bowel dis- ease. Pediatr. Gastroenterol. Hepatol. Nutr. 22, 41–49. Shin, B., Poholek, C., Yeh, W.I., and Harrington, L. (2014). T-bet controls intes- tinal chronic inflammation via regulation of IL-10 production by CD4 T cells (MUC8P.806). J. Immunol. 192, 198.7.16 Cell Reports 33, 108433, November 24, 2020Shkoda, A., Ruiz, P.A., Daniel, H., Kim, S.C., Rogler, G., Sartor, R.B., and Hal- ler, D. (2007). Interleukin-10 blocked endoplasmic reticulum stress in intestinal epithelial cells: impact on chronic inflammation. Gastroenterology 132, 190–207. Shoemaker, J., Saraiva, M., and O’Garra, A. (2006). GATA-3 directly remodels the IL-10 locus independently of IL-4 in CD4+ T cells. J. Immunol. 176, 3470– 3479. Smillie, C.S., Biton, M., Ordovas-Montanes, J., Sullivan, K.M., Burgin, G., Gra- ham, D.B., Herbst, R.H., Rogel, N., Slyper, M., Waldman, J., et al. (2019). Intra- and Inter-cellular Rewiring of the Human Colon during Ulcerative Colitis. Cell 178, 714–730.e22. Spencer, S.D., Di Marco, F., Hooley, J., Pitts-Meek, S., Bauer, M., Ryan, A.M., Sordat, B., Gibbs, V.C., and Aguet, M. (1998). The orphan receptor CRF2-4 is an essential subunit of the interleukin 10 receptor. J. Exp. Med. 187, 571–578. Sterneck, E., Zhu, S., Ramirez, A., Jorcano, J.L., and Smart, R.C. (2006). Con- ditional ablation of C/EBP beta demonstrates its keratinocyte-specific require- ment for cell survival and mouse skin tumorigenesis. Oncogene 25, 1272– 1276. Storey, J.D., Xiao, W., Leek, J.T., Tompkins, R.G., and Davis, R.W. (2005). Sig- nificance analysis of time course microarray experiments. Proc. Natl. Acad. Sci. USA 102, 12837–12842. Stumhofer, J.S., Laurence, A., Wilson, E.H., Huang, E., Tato, C.M., Johnson, L.M., Villarino, A.V., Huang, Q., Yoshimura, A., Sehy, D., et al. (2006). Inter- leukin 27 negatively regulates the development of interleukin 17-producing T helper cells during chronic inflammation of the central nervous system. Nat. Immunol. 7, 937–945. Stumhofer, J.S., Silver, J.S., Laurence, A., Porrett, P.M., Harris, T.H., Turka, L.A., Ernst, M., Saris, C.J.M., O’Shea, J.J., and Hunter, C.A. (2007). Interleu- kins 27 and 6 induce STAT3-mediated T cell production of interleukin 10. Nat. Immunol. 8, 1363–1371. Sungnak, W., Wang, C., and Kuchroo, V.K. (2019). Multilayer regulation of CD4 T cell subset differentiation in the era of single cell genomics. Adv. Immunol. 141, 1–31. Taketani, K., Kawauchi, J., Tanaka-Okamoto, M., Ishizaki, H., Tanaka, Y., Sa- kai, T., Miyoshi, J., Maehara, Y., and Kitajima, S. (2012). Key role of ATF3 in p53-dependent DR5 induction upon DNA damage of human colon cancer cells. Oncogene 31, 2210–2221. Tirosh, I., Izar, B., Prakadan, S.M., Wadsworth, M.H., 2nd, Treacy, D., Trom- betta, J.J., Rotem, A., Rodman, C., Lian, C., Murphy, G., et al. (2016). Dissect- ing the multicellular ecosystem of metastatic melanoma by single-cell RNA- seq. Science 352, 189–196. Trandem, K., Zhao, J., Fleming, E., and Perlman, S. (2011). Highly activated cytotoxic CD8 T cells express protective IL-10 at the peak of coronavirus- induced encephalitis. J. Immunol. 186, 3642–3652. Trapnell, C., Pachter, L., and Salzberg, S.L. (2009). TopHat: discovering splice junctions with RNA-Seq. Bioinformatics 25, 1105–1111. Upadhyay, V., and Fu, Y.-X. (2013). Lymphotoxin signalling in immune homeo- stasis and the control of microorganisms. Nat. Rev. Immunol. 13, 270–279. Villarino, A., Hibbert, L., Lieberman, L., Wilson, E., Mak, T., Yoshida, H., Kas- telein, R.A., Saris, C., and Hunter, C.A. (2003). The IL-27R (WSX-1) is required to suppress T cell hyperactivity during infection. Immunity 19, 645–655. Villarino, A.V., Stumhofer, J.S., Saris, C.J.M., Kastelein, R.A., de Sauvage, F.J., and Hunter, C.A. (2006). IL-27 limits IL-2 production during Th1 differentiation. J. Immunol. 176, 237–247. Wallrapp, A., Burkett, P.R., Riesenfeld, S.J., Kim, S.-J., Christian, E., Abduln- our, R.-E.E., Thakore, P.I., Schnell, A., Lambden, C., Herbst, R.H., et al. (2019). Calcitonin Gene-Related Peptide Negatively Regulates Alarmin-Driven Type 2 Innate Lymphoid Cell Responses. Immunity 51, 709–723.e6. Wang, Q., Strong, J., and Killeen, N. (2001). Homeostatic competition among T cells revealed by conditional inactivation of the mouse Cd4 gene. J. Exp. Med. 194, 1721–1730. Wang, H.,Meng, R., Li, Z., Yang, B., Liu, Y., Huang, F., Zhang, J., Chen, H., and Wu, C. (2011). IL-27 induces the differentiation of Tr1-like cells from human ll Resource OPEN ACCESSnaive CD4+ T cells via the phosphorylation of STAT1 and STAT3. Immunol. Lett. 136, 21–28. Wang, C., Yosef, N., Gaublomme, J., Wu, C., Lee, Y., Clish, C.B., Kaminski, J., Xiao, S., Meyer Zu Horste, G., Pawlak, M., et al. (2015). CD5L/AIM regulates lipid biosynthesis and restrains th17 cell pathogenicity. Cell 163, 1413–1427. Watchmaker, P.B., Lahl, K., Lee, M., Baumjohann, D., Morton, J., Kim, S.J., Zeng, R., Dent, A., Ansel, K.M., Diamond, B., et al. (2014). Comparative tran- scriptional and functional profiling defines conserved programs of intestinal DC differentiation in humans and mice. Nat. Immunol. 15, 98–108. Wei, G., Wei, L., Zhu, J., Zang, C., Hu-Li, J., Yao, Z., Cui, K., Kanno, Y., Roh, T.- Y., Watford, W.T., et al. (2009). Global mapping of H3K4me3 and H3K27me3 reveals specificity and plasticity in lineage fate determination of differentiating CD4+ T cells. Immunity 30, 155–167. Wende, H., Lechner, S.G., Cheret, C., Bourane, S., Kolanczyk, M.E., Pattyn, A., Reuter, K., Munier, F.L., Carroll, P., Lewin, G.R., and Birchmeier, C. (2012). The transcription factor c-Maf controls touch receptor development and function. Science 335, 1373–1376. Wu, C., Yosef, N., Thalhamer, T., Zhu, C., Xiao, S., Kishi, Y., Regev, A., and Kuchroo, V.K. (2013). Induction of pathogenic TH17 cells by inducible salt- sensing kinase SGK1. Nature 496, 513–517. Xiao, S., Yosef, N., Yang, J., Wang, Y., Zhou, L., Zhu, C., Wu, C., Baloglu, E., Schmidt, D., Ramesh, R., et al. (2014). Small-molecule RORgt antagonists inhibit T helper 17 cell transcriptional network by divergent mechanisms. Im- munity 40, 477–489. Xu, H., Chaudhri, V.K., Wu, Z., Biliouris, K., Dienger-Stambaugh, K., Rochman, Y., and Singh, H. (2015). Regulation of bifurcating B cell trajectories by mutual antagonism between transcription factors IRF4 and IRF8. Nat. Immunol. 16, 1274–1281. Xu, M., Pokrovskii, M., Ding, Y., Yi, R., Au, C., Harrison, O.J., Galan, C., Bel- kaid, Y., Bonneau, R., and Littman, D.R. (2018). c-MAF-dependent regulatoryT cells mediate immunological tolerance to a gut pathobiont. Nature 554, 373–377. Yosef, N., Shalek, A.K., Gaublomme, J.T., Jin, H., Lee, Y., Awasthi, A., Wu, C., Karwacz, K., Xiao, S., Jorgolli, M., et al. (2013). Dynamic regulatory network controlling TH17 cell differentiation. Nature 496, 461–468. Yoshida, H., and Hunter, C.A. (2015). The immunobiology of interleukin-27. Annu. Rev. Immunol. 33, 417–443. Yu, F., Sharma, S., Jankovic, D., Gurram, R.K., Su, P., Hu, G., Li, R., Rieder, S., Zhao, K., Sun, B., and Zhu, J. (2018). The transcription factor Bhlhe40 is a switch of inflammatory versus antiinflammatory Th1 cell fate determination. J. Exp. Med. 215, 1813–1821. Zhang, H., and Kuchroo, V. (2019). Epigenetic and transcriptional mechanisms for the regulation of IL-10. Semin. Immunol. 44, 101324. Zhang, Y., Liu, T., Meyer, C.A., Eeckhoute, J., Johnson, D.S., Bernstein, B.E., Nusbaum, C., Myers, R.M., Brown, M., Li, W., and Liu, X.S. (2008). Model- based analysis of ChIP-Seq (MACS). Genome Biol. 9, R137. Zhang, N., Schröppel, B., Lal, G., Jakubzick, C., Mao, X., Chen, D., Yin, N., Jessberger, R., Ochando, J.C., Ding, Y., and Bromberg, J.S. (2009). Regulato- ry T cells sequentially migrate from inflamed tissues to draining lymph nodes to suppress the alloimmune response. Immunity 30, 458–469. Zhang, P., Lee, J.S., Gartlan, K.H., Schuster, I.S., Comerford, I., Varelias, A., Ullah, M.A., Vuckovic, S., Koyama, M., Kuns, R.D., et al. (2017). Eomesoder- min promotes the development of type 1 regulatory T (TR1) cells. Sci. Immunol. 2, eaah7152. Zhu, C., Sakuishi, K., Xiao, S., Sun, Z., Zaghouani, S., Gu, G., Wang, C., Tan, D.J., Wu, C., Rangachari, M., et al. (2015). An IL-27/NFIL3 signalling axis drives Tim-3 and IL-10 expression and T-cell dysfunction. Nat. Commun. 6, 6072. Zhu, L., Shi, T., Zhong, C., Wang, Y., Chang, M., and Liu, X. (2017). IL-10 and IL-10 Receptor Mutations in Very Early Onset Inflammatory Bowel Disease. Gastroenterol. Res. 10, 65–69.Cell Reports 33, 108433, November 24, 2020 17 ll OPEN ACCESS ResourceSTAR+METHODSKEY RESOURCES TABLEREAGENT or RESOURCE SOURCE IDENTIFIER Antibodies InVivoMab anti-mouse CD3ε Bio X Cell Cat# BE0001-1 InVivomAb anti-mouse CD28 Bio X Cell Cat# BE0015-5 InVivomAb anti-mouse TGF-b Bio X Cell Cat# BE0057 InVivomAb polyclonal Armenian hamster Bio X Cell Cat# BE0091 IgG Chemicals, Peptides, and Recombinant Proteins Recombinant Mouse IL-27 (NS0- R&D SYSTEMS Cat# 2799-ML-010 expressed) Protein Recombinant Mouse IL-12 Protein R&D SYSTEMS Cat# 419-ML-050 Mouse IL-4, research grade Miltenyi Biotec Cat# 130-097-757 Recombinant Mouse IL-1 beta/IL-1F2 R&D SYSTEMS Cat# 419-ML-010 Protein Recombinant Mouse IL-6 Protein R&D SYSTEMS Cat# 406-ML-025 Recombinant Mouse IL-23 Protein R&D SYSTEMS Cat# 1887-ML-010 Human TGF-b1, premium grade Miltenyi Biotec Cat# 130-095-067 Liberase TL Research Grade Sigma Cat# 5401020001 DNase I Sigma Cat# 10104159001 Fixable viability dye eFluor506 eBioscience Cat# 65-0866-14 7AAD BD Biosciences Cat# 559925 Digitonin Promega Cat# G9441 Critical Commercial Assays RNeasy Plus Mini Kit QIAGEN Cat# 74134 iScript Reverse Transcription Supermix Bio-Rad Cat# 1708841 TaqMan Fast Advanced Master Mix Thermo Fisher Scientific Cat# 4444557 PolyJet In Vitro DNA Transfection Reagent SignaGen Laboratories Cat# SL100688 Dual-Luciferase Reporter Assay System Promega Cat# E1960 GeneChip Mouse Genome 430 2.0 Array Affymetrix Cat# 900497 Nextera DNA Sample Preparation Kit Illumina Cat# FC-121-1030 MinElute Reaction Cleanup kit QIAgen Cat# 28204 Chromium Single Cell 30 Library & Gel Bead 10x Genomics Cat# PN-120237 Kit v2 Chromium Single Cell A Chip Kit 10x Genomics Cat# PN-1000009 Deposited Data Raw and analyzed data This paper GEO: GSE159208 Tr1 ATAC-seq (related to Figures 2B and Karwacz et al., 2017 GEO: GSE92993 6B) Atf3 ChIP-seq (related to Figure 2B) Garber et al., 2012 GEO: GSE36104 Fosl2 ChIP-seq (related to Figure 2B) Ciofani et al., 2012 GEO: GSE40918 Tbx21 ChIP-seq (related to Figure 2B) Nakayamada et al., 2011 GEO: GSE33802 Irf8 ChIP-seq (related to Figure 2B) Xu et al., 2015 GEO: GSE70712 Experimental Models: Cell Lines 293T cells GenHunter Cat# Q401 Platinum-E (Plat-E) Retroviral Packaging Cell Biolabs Cat# RV-101 Cell Line (Continued on next page) e1 Cell Reports 33, 108433, November 24, 2020 ll Resource OPEN ACCESS Continued REAGENT or RESOURCE SOURCE IDENTIFIER Experimental Models: Organisms/Strains Mouse: C57BL/6J The Jackson Laboratory JAX: 000664 BALB/cJ The Jackson Laboratory JAX: 000651 Mouse: Foxp3-GFP Bettelli et al., 2006 N/A Mouse: 10BiT Maynard et al., 2007 N/A Mouse: Prdm1f/f Shapiro-Shelef et al., 2003 JAX: 008100 Mouse: Maff/f Wende et al., 2012 N/A Mouse: Ahr KO Schmidt et al., 1996 JAX: 002831 Mouse: Atf3f/f Taketani et al., 2012 N/A Mouse: Batf KO Schraml et al., 2009 JAX: 013758 Mouse: Cebpbf/f Sterneck et al., 2006 N/A Mouse: Ets1 KO Muthusamy et al., 1995 N/A Mouse: Fosl2f/f Karreth et al., 2004 N/A Mouse: Hif1af/f Ryan et al., 2000 JAX: 007561 Mouse: Irf1 KO Matsuyama et al., 1993 JAX: 002762 Mouse: Irf4 KO Klein et al., 2006 JAX: 009380 Mouse: Irf8f/f Feng et al., 2011 JAX:014175 Mouse: Irf9 KO Gift from Paul J. Utz RIKEN: RBRC00915 Mouse: Nfil3f/f Gascoyne et al., 2009 N/A Mouse: Stat3f/f Moh et al., 2007 JAX: 016923 Mouse: Tbx21 KO Finotto et al., 2002 JAX: 004648 Mouse: Bhlhe40 KO Jiang et al., 2008 JAX: 029732 Mouse: Hlx+/ Hentsch et al., 1996 JAX: 008313 Mouse: Stat4 Kaplan et al., 1996 JAX: 002826 Mouse: Batf3 KO Hildner et al., 2008 JAX: 013755 Mouse: Nfe2l2 KO Chan et al., 1996 JAX: 017009 Mouse: Irf7 KO Gift from Ian Rifkin N/A Mouse: Id2f/f Seillet et al., 2013 N/A Mouse: Fli1+/ Gift from Maria Trojanowska N/A Mouse: Cd4-Cre Lee et al., 2001 Taconic: 4196 Mouse: Actin-Cre Lewandoski et al., 1997 JAX: 033984 Mouse: Lck-Cre Hennet et al., 1995 JAX: 003802 Mouse: dLck-Cre Wang et al., 2001 JAX: 012837 Recombinant DNA pGL4.10[luc2] Vector Promega Cat# E665A pGL4.10-Il10 proximal promoter-luc2 This paper N/A pGL4.10-Il10 CNS-9-luc2 This paper N/A pGL4.10-Il10 HSS+2.98-luc2 This paper N/A pGL4.10-Il10 HSS+6.45-luc2 This paper N/A MSCV-IRES-GFP Gift from Tannishtha Reya Addgene #20672 MSCV-Maf-IRES-GFP This paper N/A MSCV-IRES-Thy1.1 Gift from Philippa Marrack N/A MSCV-Prdm1-IRES-Thy1.1 This paper N/A Software and Algorithms GenePattern Reich et al., 2006 https://www.genepattern.org/ EDGE Leek et al., 2006 https://www.bioconductor.org/ Tophat Trapnell et al., 2009 https://github.com/infphilo/tophat RSEM Li and Dewey, 2011 http://deweylab.github.io/RSEM/ (Continued on next page) Cell Reports 33, 108433, November 24, 2020 e2 ll OPEN ACCESS Resource Continued REAGENT or RESOURCE SOURCE IDENTIFIER DESeq2 Love et al., 2014 https://bioconductor.org/packages/ release/bioc/html/DESeq2.html RStudio RStudio https://www.rstudio.com/ ATAC-seq pipeline Lee et al., 2016 https://zenodo.org/record/211733 Integrative Genomics Viewer Robinson et al., 2017 http://software.broadinstitute.org/ software/igv/ R package Seurat v3 Butler et al., 2018 https://satijalab.org/seurat/ FlowJo FlowJo https://www.flowjo.com Prism GraphPad https://www.graphpad.comRESOURCE AVAILABILITY Lead Contact Further information and requests for resources and reagents should be directed to and will be fulfilled by the Lead Contact, Vijay Kuchroo (vkuchroo@evergrande.hms.harvard.edu). Materials Availability This study did not generate new unique reagents. Data and Code Availability Data generated in this paper has been deposited in the Gene Expression Omnibus (GEO) under accession number GEO: GSE159208. EXPERIMENTAL MODEL AND SUBJECT DETAILS Mice and Ethics Statement C57BL/6, BALB/cJ, dLckCre,Hlx+/ (Hentsch et al., 1996), Tbx21/ (Finotto et al., 2002), Irf8fl/fl (Feng et al., 2011), Prdm1fl/fl (Shapiro- Shelef et al., 2003), Nfe2l2/ (Chan et al., 1996), Hif1afl/fl (Ryan et al., 2000), Ahr/ (Schmidt et al., 1996), Batf3/ (Hildner et al., 2008), Stat3fl/fl (Moh et al., 2007), Stat4/ (Kaplan et al., 1996), Irf1/ (Matsuyama et al., 1993), Batf/ (Schraml et al., 2009), Irf4fl/fl (Klein et al., 2006), Bhlhe40/ (Jiang et al., 2008) and 10BiT (Maynard et al., 2007) mice were purchased from Jackson Lab- oratory. Cd4Cre (Lee et al., 2001) mouse was purchased from Taconic. Maffl/fl (Wende et al., 2012), Nfil3fl/fl (Gascoyne et al., 2009), Id2fl/fl (Seillet et al., 2013), Ets1/ (Muthusamy et al., 1995) and Foxp3-GFP mouse (Bettelli et al., 2006) has been previously described. Other previously described mutant strains were kindly provided by the following researchers: Fosl2fl/fl (Karreth et al., 2004), D. Littman;Atf3fl/flActb-Cre (Taketani et al., 2012), H.Weiner;Cebpbfl/fl Lck-Cre+ (Sterneck et al., 2006),M. Rincon. In addition, spleens from Irf7/, Fli1+/, Irf9/mice were obtained from Ian R. Rifkin, Maria Trojanowska, and Paul J. Utz, respectively. In vitro experiments were performed using 6-10 weeks old female and male mice. All animals were housed and maintained in conventional pathogen-free facilities at the Harvard Institute of Medicine and Hale Building for Transformative Medicine in Boston (IUCAC protocols: 2016N000444 (V.K.K.)). All experiments were performed in accor- dance to guidelines outlined by Harvard Medical Area Standing Committee on Animals and the Brigham andWomen’s Hospital Insti- tutional Animal Care and Use Committee. METHOD DETAILS Experimental methods T cell sorting and in-vitro T helper cell differentiation For the generation of time-course microarray data of Tr1 cells and validation of Il10 regulators in Tr1 cells in vitro, CD4+CD44-CD62L+CD25- naive cells were sorted from WT B6 or indicated KO and their corresponding control mice with BD FACSAria sorter, and then activated with plate-bound anti-CD3 and anti-CD28 (both at 1ug/ml) in the presence of 25ng/ml rmIL- 27 (R & D systems). 10ug/ml anti-TGFb (Bioxcell, Clone# 1D11.16.8) was also added for the microarray experiment. For RNA-seq and qPCR analysis of IL-10 producing and non-producing T helper cells, naive CD4+CD44-CD62L+GFP- cells were sorted from Foxp3-GFP; Il10-Thy1.1 double reporter mice using BD FACSAria sorter and were activated with irradiated splenocytes depleted of CD4 T cells (at the T: APC ratio of 1:6) and 2.5ug/ml soluble anti-CD3 in the presence of polarizing cytokines. Concen- tration of cytokines are as follows: 20ng/ml rmIL-12 (R & D systems) for Th1; 20ng/ml rmIL-4 (Miltenyi Biotec) for Th2; 2ng/ml ofe3 Cell Reports 33, 108433, November 24, 2020 ll Resource OPEN ACCESSrhTGFb1 and 25ng/ml rmIL-6(both fromMiltenyi Biotec) for non-pathogenic Th17; 20ng/ml rmIL-1b(Miltenyi Biotec), 25ng/ml rmIL-6 (Miltenyi Biotec), and 20ng/ml rmIL-23 (R &D systems) for pathogenic Th17; 25ng/ml of rmIL-27 (R &D systems) for Tr1. IL-10 positive (Thy1.1+) and negative (Thy1.1+) 7-AAD-TCRb+CD4+GFP- cells were re-sorted at 72 hours. Isolation of lymphocytes from colonic lamina propria To remove epithelial cells, colons were first washed for 20min in RPMI medium (GIBCO) with 3% FBS (Sigma-Aldrich), 5mM EDTA (Invitrogen) and 1mMDTT (Sigma) in a shaking incubator at 400rpm at 37C, followed by three other washes each for 30 s by vibrant vortexing in RPMI with 2mM EDTA. The tissue was then cut into little pieces and digested for 30min in RPMI with 100ug/mL Liberase TL (Sigma) and 500ug/mL DNase I (Sigma) Digestion in a shaking incubator at 400rpm at 37C. Digestion was terminated by addition of ice-cold RPMIwith 3%FCS. Cells were washed twice in RPMIwith 3%FCS, passed through a 40mmcell strainer and resuspended in ice-cold RPMI with 3% FCS and 1mM EDTA for sorting. RNA profiling by microarrays, population RNA-seq and single cell RNA-seq The temporal gene expression profiling of Tr1 cells at 17 time points during in vitro differentiation by IL-27 were measured by Affy- metrix GeneChipMouse Genome 430 2.0 Arrays. For genetic validation of the 24 TFs, naive CD4+ T cells were isolated from spleen of knockout mice and matched controls and differentiated in vitro in Tr1 polarizing conditions for 72 hours. Cells were collected and processed using an adaptation of the SMART-Seq 2 protocol (Tirosh et al., 2016), using 5uL of lysate from bulk CD4+ T cells as the input for each sample during RNA cleanup via SPRI beads (2,000 cells lysed on average in RLT). Libraries were prepared using the Nextera XT DNA Sample Prep Kit (Illumina), quantified, pooled, and then sequenced on the HiSeq 2500 (Illumnia) to an average depth of 20M reads. For scRNA-seq profiling of colonic CD4 T cells in control, Prdm1 cKO, Maf cKO, and DKO mice, live (7-AAD-) TCRb+CD4+ cells were sorted from colonic lamina propria of eachmouse with two biological replicates for each genotype. Cells were processed using Chromium Single Cell 30 Reagent Kits v2 according to manufacturer’s protocol (10X Genomics). For each biological replicate, an input of 7,000 single cells was added to an individual channel with a recovery rate of approximately 1,3002100 cells. The generated scRNA-seq libraries were sequenced on HiSeq X Ten. ATAC-seq Control, Prdm1 cKO, Maf cKO, and DKO Tr1 cells were cultured as described above for 72h with IL-27. Three to five replicates were included for each genotype. Subsequently, 6,000 viable Tr1 cells were sorted and frozen in BambankerTM cell freezing media (LYMPHOTEC Inc.) at 80C. For ATAC-seq library preparation, cells were thawed at 37C, washed once with PBS, and lysed and tagmented in 1X TD Buffer, 0.2ml TDE1 (provided in Nextera DNA Sample Preparation Kit from Illumina), 0.01% digitonin, and 0.3X PBS in 40ml reaction volume following the protocol described by Corces et al. (2016). The DNA was purified immediately with the MinElute PCR purification kit (QIAGEN), and then PCR amplified and quantified as we previ- ously described (Wallrapp et al., 2019). The library was sequenced on an Illumina NextSeq 550 system with paired-end reads of 37 base pairs in length. Quantitative RT-PCR RNA was extracted using RNeasy Plus Mini Kit (QIAGEN), cDNA was prepared using iScript Reverse Transcription Supermix (Bio- rad) and used as template for real-time qPCR run with TaqMan Fast Advanced Master Mix (Thermo Fisher Scientific) on the ViiA 7 Real-Time PCR System (Applied Biosystems). Expression was normalized to Actb. The following probes used for qPCR were pur- chased from Applied Biosystems: Il10 (Mm01288386_m1), Maf (Mm02581355_s1), Prdm1 (Mm00476128_m1), Actb (Mm00607939_s1). Flow Cytometry Single cell suspensions were stained with antibodies against surface molecules. Fixable viability dye eF506 or 7-AAD was used to exclude dead cells. For intra-cytoplasmic cytokine staining, cells were stimulated with 12-myristate 13-acetate (PMA) (50ng/ml, Sigma), ionomycin (1 mg/ml, Sigma) in the presence of Brefeldin A (Golgiplug, BD Biosciences) and Monensin (Golgistop, BD Biosci- ences) for 4-5 hours prior to staining with antibodies against surface proteins followed by fixation, permeabilization with Fixation/Per- meabilization Solution Kit (BD Biosciences) and staining with antibodies against intracellular cytokines. Data was analyzed with Flowjo. Luciferase assays 5x104 293T cells were seeded in 96 well plate one day before transfection and then transfected with Firefly luciferase reporter con- structs for Il10, Renilla luciferase reporter (internal control) and plasmids expressing specific transcription factors using PolyJet In Vitro DNA Transfection Reagent (SignaGen Laboratories). Cells were analyzed 48h later with Dual-Luciferase Reporter Assay Sys- tem (Promega). To construct reporters for Il10 enhancers, previously described enhancer regions, including the CNS-9, HSS+2.98, and HSS+6.45 (Lee et al., 2009), were cloned upstream of the Il10 minimal promoter. Fragments containing the proximal Il10 pro- moter (1.5 kb including the HSS-0.12 site) or the aforementioned enhancers were cloned into pGL4.10 Luciferase reporter plasmid (Promega). In-vivo treatment of anti-CD3 Mice were treated with 20 mg anti-CD3 monoclonal antibody (clone 145-2C11, Bio X Cell) or an isotype control (Bio X Cell) intraper- itoneally every 3 days for a total of three times. Mice were sacrificed 4h after the last treatment. CD4 T cells were purified frommesen- teric lymph node by MACS cell separation and Il10 expression was measured by qPCR.Cell Reports 33, 108433, November 24, 2020 e4 ll OPEN ACCESS ResourceT cell transfer colitis CD4+CD62L+ T cells were sorted from WT and Hlx+/ mice and cultured with plate-bound anti-CD3 and anti-CD28 antibody in the presence of 25ng IL-27. 72 h later cells were detached from the plate and rested for 48h before transferred into Rag1/ KO recip- ients. 53 105 WT or Hlx heterozygous Tr1 cells were transferred intraperitoneally into Rag1/ animals and changes in body weight were monitored weekly. Retroviral infection T cells activated with plate-bound anti-CD3 and anti-CD28 antibody in the presence of polarizing cytokines were transduced with MSCV expressing Prdm1 (marked by Thy1.1) and Maf (marked by GFP) at 24h after activation. IL-10 expression in control (Thy1.1-GFP-), Prdm1-overexpressing (Thy1.1+GFP-), Maf-overexpressing (Thy1.1-GFP+) and cells overexpressing both (Thy1.1+GFP+) was analyzed by flow cytometry. For preparation of retroviruses, Plat-E cells were transfected with MSCV vectors with PolyJet. Supernatant containing virus was harvested 48hr after transfection of Plat-E cells and then used for spin transduction of T cells with polybrene (8 mg/ml) at 2000rpm, 32C for 1hr. Computational Methods Microarray data pre-processing and analysis Individual .CEL files were RMA normalized and merged to an expression matrix using the ExpressionFileCreator of GenePattern with default parameters (Reich et al., 2006). Gene-specific intensities were then computed by taking for each gene j and sample i the maximal probe value observed for that gene. Samples were then transferred to log-space by taking log2(intensity). Differentially expressed genes (comparing to the Th0 control) were found using a method we previously described (Yosef et al., 2013). Briefly, genes that were detected in two of the four methods used were defined as differentially expressed: (1) Fold change. Requiring a 2-fold change (up or down) during at least two time points. (2) Polynomial fit. We used the EDGE software (Leek et al., 2006; Storey et al., 2005), designed to identify differential expression in time course data, with a threshold of q-value % 0.01. (3) Sigmoidal fit. We used an algorithm similar to EDGE while replacing the polynomials with a sigmoid function, which is often more adequate for modeling time course gene expression data (Chechik and Koller, 2009). We used a threshold of q-value % 0.01. (4) ANOVA. Gene expression was modeled by time (using only time points for which we have more than one replicate) and treatment. Themodel takes into account each variable independently, as well as their interaction. We report cases in which the P value assigned with the treatment parameter or the interaction parameter passed an FDR threshold of 0.01. To associate the regulation activity of a differentially expressed transcription factor with the three phases of IL-10 expression (la- tency, induction and maintenance) we segmented our time course dataset into three corresponding time windows: 0-20h, 25-48h and 54-72h. TFs were assigned to specific phases if they were differential expressed (> 1.8 Fold change) anytime during this time window. Prediction of TFs regulating the IL-27 network Using approaches as we previously described (Yosef et al., 2013), we identified potential regulators of Tr1 differentiation by computing overlaps between their putative targets and sets of differentially expressed genes grouped by k-means clustering. For every TF in our database, we computed the statistical significance of the overlap between its putative targets and each of the groups defined above using Fisher’s exact test. We included cases where p < 5 3 105 and the fold enrichment > 1.5. Population RNA-seq data pre-processing and analysis RNA-seq reads were aligned using Tophat (Trapnell et al., 2009) and RSEM-based quantification (Li and Dewey, 2011) using known transcripts (mm9), followed by further processing using the Bioconductor package DESeq2 in R (Anders and Huber, 2010). The data was normalized using TMM normalization. The TMMmethod estimates scale factors between samples that can be incorporated into currently used statistical methods for DE analysis. Post-processing and statistical analysis was carried out in R (Li and Dewey, 2011). For the analysis of the effect of different regulator KOs, differentially expressed genes were defined as genes with abs (logFC be- tween control and KO) > 1. For comparison between IL-10+ and IL-10- cells, differentially expressed genes were defined based on the raw counts with a single call to the function DESeq2 (Love et al., 2014) (FDR-adjusted P value < 0.05). Heatmap figures were generated using pheatmap pack- age (https://cran.r-project.org/web/packages/pheatmap/index.html). ATAC-seq analysis Generation and analysis of ATAC-seq data for in-vitro differentiated Tr1 cells at 24 h and 72 h were performed in our previously pub- lished study (Karwacz et al., 2017). A publicly available ATAC-seq pipeline (Lee et al., 2016) was used for the processing of ATAC-seq on Prdm1 cKO, Maf cKO and DKO Tr1 cells. Briefly, reads were aligned to the mm10 genome using Bowtie2 and filtered to remove duplicates and mitochondrial reads. Biological replicate for each group were merged peaking-calling using MACS2 (Zhang et al., 2008). Integrative Genomics Viewer (IGV) was used for visualization of ATAC-seq peaks. Single cell RNA-seq analysis Data preprocessing. De-multiplexing, alignment to the mm10 mouse transcriptome and UMI-collapsing were performed using the Cellranger toolkit (version 2.1.0, 10X Genomics). Subsequent analysis was performed with R package Seurat v3 (Butler et al., 2018). For downstream processing we filtered out low quality cells that had (1) a low number (< 500) of unique detected genes, and (2) a high mitochondrial content (15%) determined by the ratio of reads mapping to the mitochondria. A small proportion of cells were identified as contamination by macrophages, innate lymphoid cells, intraepithelial lymphocytes and fibroblasts, and weree5 Cell Reports 33, 108433, November 24, 2020 ll Resource OPEN ACCESSexcluded from downstream analysis. To account for differences in sequencing depth across cells, UMI counts were normalized by the total number of UMIs per cell and converted to transcripts-per-10,000 before being log transformed (henceforth ‘‘log(TP10K+1)’’). PCA and clustering Highly variable geneswere selected using the ‘mean.var.plot’ method in FindVariableFeatures functionwith default settings, resulting in 341 genes which are then used for PCA analysis by RunPCA function. We used the first 40 PCs for subsequent analyses as they capture the majority of signal in an elbow plot, but we also confirmed that the resulting analyses were not particularly sensitive to the above-mentioned choice of parameters. The cells were clustered via Seurat’s FindClusters function, which optimizesmodularity on a K-nearest-neighbor (KNN) graph computed from the top eigenvectors using Louvain algorithm, with nn.eps at 0.5, resolution at 0.4, and n.start at 10. These parameters resulted in clusters that captured major genotype- related separations, known T cell subgroups, and statistically validated transcriptional distinct sections of interest while avoiding subdivisions of relatively uniform parts of the data. To visualize the data, UMAP plots were generated using Seurat’s RunUMAP function with min.dist at 0.75. Cell type assignment To identify which T cell subtype each cluster represents, we identifiedmarkers of each cluster using Seurat’s FindAllMarkers function with min.pct at 0.25. The top 200 genes of each cluster were then used as input for My Geneset module of Immgen (immgen.org). We assigned identity to each cluster based on the cell population in the Immgen database that display highest expression of its marker genes and confirmed the designation by expression of known marker genes (Figure S5A). Gene signatures Scoring gene signature was performed using AddModuleScore function of Seurat based on strategies described by Tirosh et al. (2016). Markers of cell cycles including G2/M phase and S phase were provided by Tirosh et al. (2016). Th1 signature was manually curated based on literature. Th17 signature was generated by comparing microarrays of in vitro cultured Th17 cells to other T helper cells, including naive, Th1, Th2, iTreg and nTreg cells (Wei et al., 2009; Xiao et al., 2014). CD4 T cells signature from ulcerative colitis patients contains genes upregulated in CD4 T cells from biopsies of inflamed intestinal tissue in patients compared to those from healthy tissue in healthy controls profiled by scRNA-seq (Smillie et al., 2019). IBD associated GWAS genes were compiled from liter- ature (Graham and Xavier, 2020). Differential expression analysis Differentially expressed genes were tested using MAST (Finak et al., 2015) by calling FindMarkers function in Seurat. To find unique markers for Prdm1/Maf DKO Tregs, DKO Tregs were compared against Treg cells in both single KO and control groups. QUANTIFICATION AND THE STATISTICAL ANALYSIS Unless otherwise specified, all statistical analyses were performed using the two-tail Student’s t test using GraphPad Prism software. P value less than 0.05 is considered significant (p < 0.05 = *; p < 0.01 = **; p < 0.001 = ***, p < 0.0001 = ****. Data were represented as mean ± s.e.m. unless otherwise specified. For certain types of numeric computations for transcriptomic data, the smallest P value that R can report is < 2.2 3 1016.Cell Reports 33, 108433, November 24, 2020 e6