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R. Agarwal, A.F. Clark, R.J. Wordinger; Effect of Exogenous Nerve Growth Factor (NGF) on the Expression of MMPs and TIMPs by Cells Isolated From the Human Optic Nerve Head . Invest. Ophthalmol. Vis. Sci. 2005;46(13):1260.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Primary open–angle glaucoma involves pathophysiological changes in the optic nerve head (ONH) including cupping, excavation and remodeling of the extracellular matrix (ECM). Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) are known to control ECM remodeling. Expression of MMPs/TIMPs in the human ONH may be involved in remodeling the ECM in response to elevated intraocular pressure (IOP) and/or ischemic/hypoxic conditions. Previously our laboratory has shown that ONH astrocytes and lamina cribrosa (LC) cells secrete NGF. In addition we reported that ischemia/hypoxia causes an increased secretion of NGF by cultured ONH astrocytes and LC cells. The purpose of this study was to (a) determine which specific MMPs and TIMPs are expressed by ONH astrocytes and LC cells and (b) determine if exogenous NGF alters MMP and/or TIMP expression. Methods: Well–characterized human ONH astrocytes (N=5) and LC cells (N=5) were utilized and treated with or without NGF (50 ng/ml for 48 hrs.). The expression of mRNA and protein levels for TIMPs (TIMP1–4) and MMPs (MMP–1, MMP–2, MMP–3, MMP–9 and MMP–12) was determined in both ONH astrocytes and LC cells by RT–PCR analysis, immunocytochemistry and western blotting respectively. Immunoassays (ELISA) were used to determine secretion of MMP 1–3 and TIMP–1 by both ONH astrocytes and LC cells following exogenous NGF. Results: Using RT–PCR analysis, mRNA for TIMP1–4 and MMP–1, MMP–9 and MMP–12 was detected in both ONH astrocytes and LC cells. Variable mRNA expression was detected for MMP–3 and MMP–9 by ONH astrocytes and LC cells. The presence of protein for TIMP–1, TIMP– 2 and TIMP–3, MMP–1, MMP–2, MMP–3, MMP–9 and MMP–12 was demonstrated in both ONH astrocytes and LC cells. MMP–1 and TIMP–1 were secreted in ONH astrocytes and LC cells. Furthermore, MMP–1 protein levels are increased by exogenous NGF treatment in both ONH astrocytes and LC cells. Conclusions: These studies demonstrate that the cells from human ONH express and secrete specific MMPs and TIMP 1–4. Exogenous NGF treatment causes an increase in protein level and secretion of MMP–1 by both ONH astrocytes and LC cells.
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