Tissue inhibitors of metalloproteinases (TIMPs) comprise a family of four proteins in humans that modulate the turnover of the extracellular matrix by regulating the activities of endopeptidases that catalyze its degradation, especially the matrix metalloproteinases (MMP). In general, the four TIMPs are broad-spectrum tight binding inhibitors of MMPs with individual differences in specificity. In this study, we attempted to understand the basis of such variation by using membrane type-1 MMP (MT1-MMP) as a model, since it is inefficiently inhibited by TIMP-1 in contrast with the other TIMPs. We designed and engineered mutations in the N-domain of TIMP-1, based on current knowledge of TIMP interactions. By measuring inhibition levels of each mutant against several MMPs, including MT1-MMP, we were able to obtain a triple mutant with an vii improved affinity for MT1-MMP. / Our results, along with previous data, confirm that multiple residues in the critical interface segments between TIMPs and MMPs, namely at positions 2, 4, 5, 6, and 98, are key in determining the basic interaction between the two molecules. The second part of this work focused on naturally occurring mutations in TIMP-3 which cause an early form of macular degeneration called Sorsby's Fundus Dystrophy (SFD). The TIMP-3 mutants identified so far share certain features but the mechanism by which they result in macular disease is not yet understood. As an initial step, we expressed recombinant TIMP-3 carrying a truncation mutation, glutamic acid 139 to a stop codon (E139X), and assessed its activity towards representative MMPs and tumor necrosis factor-(Sa (Bconverting enzyme, another metalloproteinase normally inhibited by TIMP-3. Our results indicate that this mutation does not impair the inhibitory activity of TIMP-3. / Expression of this mutant in mammalian retinal cells revealed a difference in localization between wild-type and E139X mutant TIMP-3. Therefore, we concluded that the SFD mutations may actually influence the processing and/or binding properties of TIMP-3 in the retina. / by Asmaa Bilal Hamze. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

The Royal College of Surgeons (RCS) rat was used as a model of human retinal degenerative disease, and for studying the efficacy of cell transplanation treatments. In order to characterize the spatial vision of the RCS strain, the visual acutiy and contrast sensitivity of adult non-dystrophic RCS rats was measured. The acuity and contrast sensitivity of these rats was normal. The acuity of dystrophic RCS rats was alos characterized to determine how photoreceptor degeneration affects vision. These rats progressively lost visual acuity from one month of age until elevn months of age when they were judged to be blind. The degeneration of vision in these animals was more protacted than would be predicted from previous anatomical and electrophysiological measures. Subretinal transplantation of human-derived Retinal Pigment Epithelial (RPE) cells and human Schwann cells into the dystrophic RCS rat significantly delayed the loss of visual acuity. These studies show that cell transplantation may be a viable method of limiting loss of vision in humans with retinal degenerative blinding diseases. / vii, 77 leaves ; 29 cm.

The established model used for evaluating potential therapies for retinal disease has significant limitations. A new model is proposed to account for these limitations: the visual adaptation model. The visual adaptation model was developed to provide a novel approach for testing potential treatments for retinal disease, and the work in this thesis provides empirical support for this model. Specifically, we evaluated two potential therapies for retinal degenerative disease and examined their effects on vision and retinal anatomy. In addition, the profile of retinal reorganization and its functional correlates were examined in RCS rats and transgenic rats which express a rhodopsin mutation; however, immunohistological work targeted one specific line (S334ter-4). Collectively, these studies provide evidence that supports the retinal adaptation model. These studies also provide a novel view of retinal and visual function in retinal disease which should be considered when evaluating treatments involving retinal degeneration. / xvii, 205 leaves : ill. ; 29 cm. --