Targeting RhoA/ROCK Signaling to Modulate Extracellular Matrix Remodeling in Corneal Endothelial Dystrophies

Fuchs endothelial corneal dystrophy (FECD) involves pathological extracellular matrix (ECM) accumulation within Descemet's membrane, leading to guttae formation, endothelial dysfunction, and vision impairment. As current treatment is primarily surgical, we investigated whether Rho-associated protein kinase (ROCK) inhibition can reduce fibrotic ECM remodeling in FECD and related corneal endothelial diseases.

Endothelial cell-Descemet membrane specimens from FECD, pseudophakous bullous keratopathy (PBK), pseudoexfoliation keratopathy (PEX-K), and normal donor corneas were treated ex vivo with ripasudil or comparator ROCK inhibitors (netarsudil, Y-27632). Complementary in vitro studies used human corneal endothelial cells. ROCK activity, ECM expression, matrix metalloproteinase (MMP) activity, and TGF-β/Smad signaling were analyzed using molecular and imaging techniques.

Relative to controls, FECD samples showed constitutive ROCK and TGF-β signaling activation. Ripasudil suppressed ROCK activity and downregulated fibrosis-associated ECM components (including collagens I/III, fibronectin, agrin, TGFBI, clusterin, and tenascin-C), while shifting the MMP-tissue inhibitor of metalloproteinases (TIMP) balance to enhance ECM turnover. These effects were accompanied by reduced ECM deposition and attenuation of TGF-β/Smad signaling, alongside broad transcriptional reprogramming related to fibrosis, inflammation, and cytoskeletal dynamics. Similar ECM-modulating effects were observed in PBK and PEX-K, with ripasudil showing the most pronounced effects among tested inhibitors.

ROCK activation contributes to pathological ECM alterations in FECD, and its pharmacologic inhibition with ripasudil suppresses pro-fibrotic ECM production, promotes ECM-remodeling pathways, and supports restoration of ECM homeostasis. These findings suggest ROCK inhibition as a promising non-surgical therapeutic strategy for FECD and related corneal endothelial disorders, warranting further validation in preclinical studies.