This is a new application for a R01. The long-term objective of this grant is to identify integrin signaling mechanisms that can be used as therapeutic targets to control and lower intraocular pressure. The glaucomas, which lead to irreversible loss of retinal ganglion cells, affect approximately 67 million people worldwide. They are commonly associated with elevated levels of intraocular pressure (IOP) due to a reduction in aqueous humor outflow from the trabecular meshwork (TM). Although a number of physiological factors are known to regulate outflow facility, one of the key factors that have emerged as an important regulatory mechanism for outflow facility is the contractile properties of the TM. At the present, it is unclear what molecular events regulate contractility in the TM. Studies from our laboratory have shown that the signaling properties of bioactive fragments from the extracellular matrix (ECM) and their receptors (integrins) can be used to regulate the contractility of the TM and increase outflow facility in cultured anterior segments. In particular we have shown that a bioactive domain from fibronectin called the HepII domain activates a ?4?1 integrin signaling pathway that decreases cell contractility in cultured TM cells. Our preliminary data strongly supports the hypothesis that manipulation of integrin signaling pathways in the TM that modify cellular contractility can be used to regulate outflow facility. The objective of this research is to identify possible ways to target integrin signaling pathways in the TM in order to increase outflow facility. To this end, we propose three approaches to activate the ?4?1 signaling pathway in cultured anterior segments. First, use lentiviral vectors to express a mini-HepII gene in the TM. Second, over express a constitutively activated ?4 integrin subunit in the TM. Third, express peptides from the cytoplasmic domain of the ?4-subunit or the integrin binding protein, paxillin which disrupt cell adhesion and decrease cell contractility. The studies proposed in this application will not only enhance our understanding of the role of integrin signaling in the TM, but it will identify new ways to target cell contractility in the TM.

Public Health Relevance

Glaucoma is the second most common cause of blindness in the U.S. and the most common cause of blindness among African-Americans. Increased intraocular pressure (IOP) is a common risk factor for glaucoma. The goal of this project is to identify signaling pathway(s) that can be activated to reduce IOP and be used as potential targets to treat glaucoma.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Study Section
Anterior Eye Disease Study Section (AED)
Program Officer
Chin, Hemin R
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University of Wisconsin Madison
Schools of Medicine
United States
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Faralli, Jennifer A; Clark, Ross W; Filla, Mark S et al. (2015) NFATc1 activity regulates the expression of myocilin induced by dexamethasone. Exp Eye Res 130:9-16
Slauson, Sarah R; Peters, Donna M; Schwinn, Marie K et al. (2015) Viral Vector Effects on Exoenzyme C3 Transferase-Mediated Actin Disruption and on Outflow Facility. Invest Ophthalmol Vis Sci 56:2431-8
Gagen, Debjani; Faralli, Jennifer A; Filla, Mark S et al. (2014) The role of integrins in the trabecular meshwork. J Ocul Pharmacol Ther 30:110-20
Filla, Mark S; Clark, Ross; Peters, Donna M (2014) A syndecan-4 binding peptide derived from laminin 5 uses a novel PKCε pathway to induce cross-linked actin network (CLAN) formation in human trabecular meshwork (HTM) cells. Exp Cell Res 327:171-82
Faralli, Jennifer A; Gagen, Debjani; Filla, Mark S et al. (2013) Dexamethasone increases αvβ3 integrin expression and affinity through a calcineurin/NFAT pathway. Biochim Biophys Acta 1833:3306-13
Clark, Ross; Nosie, Amanda; Walker, Teresa et al. (2013) Comparative genomic and proteomic analysis of cytoskeletal changes in dexamethasone-treated trabecular meshwork cells. Mol Cell Proteomics 12:194-206
Gagen, Debjani; Filla, Mark S; Clark, Ross et al. (2013) Activated αvβ3 integrin regulates αvβ5 integrin-mediated phagocytosis in trabecular meshwork cells. Invest Ophthalmol Vis Sci 54:5000-11
Faralli, Jennifer A; Newman, Jessica R; Sheibani, Nader et al. (2011) Integrin-linked kinase regulates integrin signaling in human trabecular meshwork cells. Invest Ophthalmol Vis Sci 52:1684-92
Filla, Mark S; Schwinn, Marie K; Nosie, Amanda K et al. (2011) Dexamethasone-associated cross-linked actin network formation in human trabecular meshwork cells involves ýý3 integrin signaling. Invest Ophthalmol Vis Sci 52:2952-9