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dc.contributor.advisorRam Sasisekharan.en_US
dc.contributor.authorBerry, David (David A.)en_US
dc.contributor.otherMassachusetts Institute of Technology. Biological Engineering Division.en_US
dc.date.accessioned2006-09-28T15:12:28Z
dc.date.available2006-09-28T15:12:28Z
dc.date.copyright2005en_US
dc.date.issued2005en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/34153
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2005.en_US
dc.descriptionIncludes bibliographical references (p. 252-285).en_US
dc.description.abstractGlycosaminoglycans (GAGs) are complex polysaccharides that exist both on the cell surface and free within the extracellular matrix. The intrinsic sequence variety stemming from the large number of building blocks that compose this biopolymer leads to substantial information density as well as to the ability to regulate a wide variety of important biological processes. With the recent and progressive emergence of biochemical and analytical tools to probe GAG structure and function, efforts can be taken to understand the role of GAGs in cell biology and in disease in the various physiological locations where GAGs can exist. As a first step to probe the functions of GAGs, the heparin/heparan sulfate-GAG (HSGAG)-fibroblast growth factor (FGF) system was examined. Understanding the role of HSGAGs in inducing FGF2 dimerization led to the development of a novel engineered protein that was found to be effective at promoting functional recovery in stroke. Subsequently, methods to isolate HSGAGs from the cell surface were optimized and the ability of HSGAGs to support FGF signaling was investigated. Cell surface HSGAGs can define the responsiveness of a given cell to FGF1 and FGF2 through multiple receptor isoforms. Stromal cell derived HSGAGs were also identified as critical regulators of tumor cell growth and metastasis, effecting not only FGF2., but also 1-integrin signaling.en_US
dc.description.abstract(cont.) Other GAGs, including dermatan sulfates, were characterized as modulators of FGFs and vascular endothelial growth factors. Finally, FGFs and HSGAGs were found to have important roles in maintaining epithelial monolayer integrity, with syndecan-l serving as a critical factor in inflammatory bowel disease. In addition to understanding HSGAGs in their normal physiological settings, techniques to internalize them were developed. Poly(3-amino ester)s were found to condense heparin and enable its endocytosis into cells. Internalized heparin is preferentially taken up by cancer cells, which often have a faster endocytic rate than non-transformed cells, and promotes apoptotic cell death. Internalized heparin can also be used as a tool to probe cell function. In Burkitt's lymphoma, poly(3-amino ester)-heparin conjugates served to identify cell surface HSGAGs as an important modulator of cell growth that can be harnessed to inhibit growth. Finally, studies that sought to broaden the scope of GAG biology were undertaken. Cell surface HSGA(:is were identified as mediators of vascular permeability. Furthermore a novel technique to immobilize GAGs was employed. The interactions between GAG and substrate were via hydrogen bonding. Immobilization of GAGs alters their properties, such that they can affect cells in ways distinct from GAGs free in the ECM.en_US
dc.description.abstract(cont.) Furthermore, immobilized GAGs can regulate cancer cell adhesion, growth and progression, and may offer a new way to regulate the activity of cancer cells. In addition to directly providing new potential therapeutics and drug targets, these studies represent a foundation to enable additional studies of GAG function. Future work harnessing the techniques presented may open new avenues of research and facilitate the development of novel GAG-based therapeutics.en_US
dc.description.statementofresponsibilityby David Berry.en_US
dc.format.extent285 p.en_US
dc.format.extent18425848 bytes
dc.format.extent18439558 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsMIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectBiological Engineering Division.en_US
dc.titleGlycosaminoglycan regulation of cell functionen_US
dc.title.alternativeGAG regulation of cell functionen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Biological Engineering
dc.identifier.oclc69018584en_US


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