TRPV4 regulates intraocular pressure through trabecular meshwork contractility and fibrosis

Intraocular pressure (IOP) is dynamically regulated by the contractility and viscoelasticity of the trabecular meshwork (TM). Two recent studies identified the polymodal cation channel TRPV4 as a central mechanosensor that integrates mechanical, biochemical, and circadian signals to set the IOP levels. Pharmacological TRPV4 inhibition, global Trpv4 knockout, and conditional deletion of Trpv4 attenuated pathological ocular hypertension induced by corticosteroids, TGFβ2, or angle occlusion, as well as physiological nocturnal IOP elevation. Conversely, the selective TRPV4 agonist GSK1016790A raised IOP when injected intracamerally but lowered it when applied topically, indicating compartment-specific action. TRPV4 activation induced actomyosin contractility and ECM deposition in cultured TM cells and increased outflow resistance in biomimetic 3D scaffolds and hydrogels, with the impact reversed by TRPV4 inhibition and gene deletion. TGFβ2 strongly upregulated transcription and functional expression of TRPV4, revealing a feed-forward fibrotic loop that may contribute to myofibroblast transdifferentiation of the stressed TM. Collectively, these findings established TRPV4 as an essential mediator of TM contractility, stiffness, and IOP homeostasis. Its expression in key pressure-regulating tissues (TM, Schlemm's canal, ciliary body, and ciliary muscle) positions the channel as a convergence point for diverse glaucoma risk factors that regulate aqueous fluid production and drainage, and thus as a promising therapeutic target to lower IOP without global disruption of actin polymerization.