TGFβ2-induced outflow alterations in a bioengineered trabecular meshwork are offset by a rho-associated kinase inhibitor

Abstract

Members of the transforming growth factor beta (TGFβ) cytokine family have long been associated with affecting several cellular functions, including cell proliferation, differentiation and extracellular matrix (ECM) turnover. Of particular interest to this work, TGFβ2 has been linked to most types of glaucomas as a potential fibrotic agent that can cause elevation of intraocular pressure (IOP). Given that the trabecular meshwork (TM) provides most of aqueous humor outflow resistance in the eye, an in vitro bioengineered human TM (HTM) model has been created and validated by analyzing effects of TGFβ2 on transcellular pressure changes and outflow facility. These changes were correlated with several biological alterations induced by this cytokine, including ECM production and overexpression of HTM-marker myocillin. Furthermore, this TM model has been used to extend current knowledge of gene expression of cytokines involved in TGFβ-induced ECM turnover over time. In particular, the ability for a ROCK-inhibitor to diminish the effect of TGFβ on TM was demonstrated. This work supports the notion that anti-fibrotic activities of ROCK-inhibitors could counteract the elevation of IOP and increased strain observed in glaucomatous TM.

Involvement of autotaxin in the pathophysiology of elevated intraocular pressure in Posner-Schlossman syndrome

“…5A). Compared to rapid changes of outflow facility mediated by TGFβ2 38 , it has been reported that the effect of TGFβ1 to cause IOP elevation follows after the effect of TGFβ2 to elevate IOP 49 . This decreased permeability was attenuated by the LPA receptor antagonist, ROCK inhibitors, and TGF-β receptor inhibitor (Fig.…”

“…Several previous studies have also shown that cytoskeletal changes induced by ECM deposition and fibrosis of HTM cells impair AH outflow through the TM, leading to IOP elevation. These changes appear to involve the Rho/ROCK pathway, which has been implicated in the control of the contractile and biomechanical properties of the TM and Schlemm's canal 38,39 . We saw a similar correlation between increased ATX and elevated IOP in our previous study.…”

Role of the Autotaxin-LPA Pathway in Dexamethasone-Induced Fibrotic Responses and Extracellular Matrix Production in Human Trabecular Meshwork Cells

“…Previous work has shown that cytoskeletal changes correlate with increased ECM production and fibrogenic activity of HTM cells upon impairment of AH outflow following TM obstruction and IOP elevation. 49,50 Notably, these changes appear to involve the Rho/ROCK pathway, which has been implicated in the control of the contractile and biomechanical properties of cells and tissues. 49 In the present study, immunostaining revealed significant ATX expression in conventional outflow pathway specimens of glaucoma patients.…”

“…49,50 Notably, these changes appear to involve the Rho/ROCK pathway, which has been implicated in the control of the contractile and biomechanical properties of cells and tissues. 49 In the present study, immunostaining revealed significant ATX expression in conventional outflow pathway specimens of glaucoma patients. ATX was upregulated and secreted from HTM cells following Dex treatment as demonstrated by immunofluorometry, qRT-PCR, immunoblot analysis, and two-site immunoenzymetric and lysoPLD assays.…”

Development of a Novel Intraocular-Pressure-Lowering Therapy Targeting ATX

“…[4][5][6][7] Histological analysis indicates that the extracellular matrix (ECM) accumulates and increases resistance in the trabecular pathway. 8,9) Glaucoma is classified into two major types: open-angle glaucoma (OAG) and angle-closure glaucoma (ACG). The latter indicates an anatomically closed angle and, therefore, a surgical procedure is performed prior to medical treatment for IOP reduction.…”