GAGs have emerged as critical signaling molecules in an array of cell signaling events. Although dermatan sulfate (DS) is the most abundant GAG in the skin and in wound fluid, this represents an area of wound healing which remains to be more extensively evaluated through the assessment of cellular signaling events required for repair. DS has been shown to stimulate cellular proliferation via Fibroblast Growth Factor-2 (FGF-2) and FGF-7 mediated signaling more so than the more extensively studied GAG, heparan sulfate (HS). The purpose of this study is to further characterize the effect of DS on Fibroblast Growth Factor signaling in vitro, and extrapolate these findings to a human physiologic setting. The overall hypothesis is that FGF-10 and FGF-22 prefer DS over HS, and that the population of DS-binding proteins in the wound milieu can significantly influence tissue repair.
In Aim I, we will determine if DS is preferred over HS in FGF10 and FGF-22 mediated signaling using an in vitro biochemical approach. The binding capability, proliferative capacity, and structural specificity of DS-dependent FGF/FGF receptor interactions will be assessed.
Aim II is designed to evaluate human wound fluid to identify the FGFs that more strongly bind DS over HS through an in vivo molecular approach. In addition, the effect of DS on FGF localization and wound closure will be assessed. The proposed experiments will elucidate the role of DS in FGF-cell signaling events required for optimal tissue repair and characterize the expression patterns of DS-binding proteins, which can ultimately be used as a diagnostic marker in pathologic disease. Clinically, it has been suggested that GAGs play a role in the pathogenesis of skin disease. Finding a dependence for DS by the essential FGFR2-IIIB ligands would predict that a disorder of DS synthesis or degradation would disrupt normal wound repair. Specifically, we suspect that the balance of DS present in abnormal wounds will be different than that observed during normal repair, which is supported by a few clinical studies. Hence, the analysis of the levels and/or sulfation of DS in human wound fluid from normal or diseased individuals is a prospective clinical direction for this research proposal, which may yield a diagnostic tool for abnormal wound healing and novel therapeutic approaches to promote normal wound repair. Overall, the techniques proposed allow for exposure to new molecular and biochemical methods with which to analyze protein and carbohydrate function and innate immunity in dermal wound healing. ? ? ?
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