ABSTRACT
Members of the transforming growth factor beta (TGFß) 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, TGFß2 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 TGFß2 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 TGFß-induced ECM turnover over time. In particular, the ability for a ROCK-inhibitor to diminish the effect of TGFß 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.
Subject(s)
Amides/pharmacology , Pyridines/pharmacology , Tissue Engineering/methods , Tissue Scaffolds , Trabecular Meshwork/drug effects , Transforming Growth Factor beta2/pharmacology , rho-Associated Kinases/antagonists & inhibitors , Actins/genetics , Actins/metabolism , Animals , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Epoxy Compounds/chemistry , Eye Proteins/genetics , Eye Proteins/metabolism , Gene Expression Regulation , Glycoproteins/genetics , Glycoproteins/metabolism , Humans , Intraocular Pressure/physiology , Models, Biological , Perfusion , Polymers/chemistry , Signal Transduction , Tissue Culture Techniques , Trabecular Meshwork/cytology , Trabecular Meshwork/metabolism , Transforming Growth Factor beta2/antagonists & inhibitors , alpha-Crystallin B Chain/genetics , alpha-Crystallin B Chain/metabolism , rho-Associated Kinases/genetics , rho-Associated Kinases/metabolismABSTRACT
Intraocular pressure (IOP) is mostly regulated by aqueous humor outflow through the human trabecular meshwork (HTM) and represents the only modifiable risk factor of glaucoma. The lack of IOP-modulating therapeutics that targets HTM underscores the need of engineering HTM for understanding the outflow physiology and glaucoma pathology in vitro. Using a 3D HTM model that allows for regulation of outflow in response to a pharmacologic steroid, a fibrotic state has been induced resembling that of glaucomatous HTM. This disease model exhibits HTM marker expression, ECM overproduction, impaired HTM cell phagocytic activity and outflow resistance, which represent characteristics found in steroid-induced glaucoma. In particular, steroid-induced ECM alterations in the glaucomatous model can be modified by a ROCK inhibitor. Altogether, this work presents a novel in vitro disease model that allows for physiological and pathological studies pertaining to regulating outflow, leading to improved understanding of steroid-induced glaucoma and accelerated discovery of new therapeutic targets. Biotechnol. Bioeng. 2016;113: 1357-1368. © 2015 Wiley Periodicals, Inc.
