Mechanotransduction in trabecular meshwork cells: Rho/ROCK-dependent responses to substrate stiffness

Elevated intraocular pressure (IOP) is a major risk factor for glaucoma. Trabecular meshwork cells (TMCs) play a crucial role in modulating IOP by regulating the aqueous outflow resistance. In glaucoma, the stiffening of trabecular meshwork (TM) tissue is believed to affect aqueous humor outflow, highlighting the importance of substrate stiffness in influencing TMC behavior. However, the molecular mechanisms by which substrate stiffness impacts TMCs are still not fully understood. This study investigates the role of the Rho/ROCK pathway in the effect of substrate stiffness on TMCs. Human TMCs (hTMCs) and porcine TMCs (pTMCs) were cultured on substrates of varying stiffness with Rho/ROCK pathway inhibitor Y-27632 to assess the alterations in Rho/ROCK pathway molecules, cytoskeletal organization, and cellular functions. The results indicate that stiffer substrates generally lead to decreased ROCK levels, multi-oriented F-actin organization, increased cellular contraction, and enhanced cell migration. Notably, these effects were diminished or negated by Rho/ROCK pathway inhibition, which suggests that the Rho/ROCK pathway is at least partially responsible for mediating substrate stiffness affecting TMC behavior. This study highlights the significance of the mechano-microenvironment of the TM in glaucoma pathogenesis and deepens the understanding of the Rho/ROCK pathway as a promising therapeutic target for glaucoma treatment.