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Hannah Yoo, Haiyan Li, Ana N Strat, Haven Roberts, Daniel W Stamer, Alison Patteson, Robert W Weisenthal, Preethi S Ganapathy, Samuel Herberg; Targeting YAP/TAZ mechanoregulation with statins to reverse glaucomatous trabecular meshwork stiffening. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1647.
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© ARVO (1962-2015); The Authors (2016-present)
Trabecular meshwork (TM) stiffening in primary open-angle glaucoma (POAG) arises from elevated ROCK-mediated TM cell contraction and extracellular matrix (ECM) deposition/crosslinking. YAP/TAZ play central roles in TM mechanoregulation and increased YAP/TAZ activity has been linked to glaucomatous TM stiffening. Common cholesterol-lowering statins competitively inhibit HMG-CoA reductase (HMGCR), which potently decreases YAP/TAZ activity. Statins also inhibit ROCK activity upstream of YAP/TAZ. Here, we investigate whether statins can reverse glaucomatous TM cell dysfunction using a tissue-engineered TM hydrogel model.
Normal TM/glaucomatous GTM cells were isolated from surgical discard corneal rims/POAG globes. Cells were plated on glass coverslips or encapsulated in photocrosslinked hydrogels (collagen type I, elastin-like polypeptide and hyaluronic acid). Glaucomatous conditions were induced with DEX/TGF-β2, then treated with cerivastatin or simvastatin; GTM cells were used for validation and proven ROCK inhibitor Y27632 served as treatment control. Cell morphology and cytoskeletal organization were assessed by phalloidin staining for f-actin. Immunoblot and immunostaining were used to evaluate YAP/TAZ expression/activity and changes in cell contractile force regulation. TM hydrogel contraction and stiffness were determined by longitudinal imaging and oscillatory rheology.
Induced TM and GTM cells exhibited decreased cytoplasmic (inactive) pYAP and increased nuclear (active) YAP/TAZ with increased downstream TGM2 (an ECM crosslinking enzyme) vs. controls (p<0.01); this was significantly reduced with either statin in a dose- and time-dependent manner. These effects were reversed by supplementation of mevalonate, thus bypassing statin-mediated HMGCR inhibition. Statin treatment restored glaucomatous actin stress fibers, and pMLC/α-SMA levels to baseline. Immunostaining revealed significant statin-mediated reduction of glaucomatous fibronectin deposition. Pathologic TM hydrogel contraction and stiffening were potently rescued with statin treatment; constructs were significantly relaxed and softened (p<0.01), comparable to direct ROCK inhibition.
Our data suggest that indirectly targeting the YAP/TAZ mechanoregulatory axis with statins presents an intriguing avenue for treating glaucomatous TM dysfunction with high translational potential.
This is a 2021 ARVO Annual Meeting abstract.
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