Segmental Mechanobiology of Normal and Glaucomatous Human Trabecular Meshwork Cells

Glaucoma is a leading cause of irreversible blindness worldwide, with elevated intraocular pressure (IOP) serving as the major risk factor for disease onset and progression. IOP is largely determined by aqueous humor outflow resistance in the conventional pathway, where interactions between trabecular meshwork (TM) cells and the surrounding extracellular matrix (ECM) are pivotal. In this study, we examined the segmental mechanobiology of normal and glaucomatous human TM cells isolated from high-flow (HF) and low-flow (LF) regions of the outflow pathway of normal and primary open-angle glaucoma (both male and female). Cells were seeded on type I collagen gels with fibrillar elastic moduli of 4.7 kPa and 27.7 kPa to approximate the ECM conditions of normal and glaucomatous eyes, respectively. We employed 3D traction force microscopy to quantify time-dependent contractile forces in the cells as well as curl, divergence, orientation, and tensile strain in the collagen fibers within 12 h postseeding. We also analyzed the organization of actin, microtubule, and intermediate filaments in normal and glaucomatous TM cells from both HF and LF regions. Multivariable mixed-effects models showed that, after accounting for fibrillar stiffness, time, normal/glaucoma status, and sex, HF cells generated ∼1.6-fold higher mean traction (window averaged, ∼5-6 cells) and ∼1.4-fold higher tensile strain than LF cells and induced ∼1.5-fold greater collagen curl (p < 0.001 for all), whereas divergence and glaucoma versus normal difference were not significant in this data set. Stiffer gels increased the collagen fibril preferred orientation angle (HF > LF), and glaucomatous LF cells showed persistently disorganized actin and microtubules with little change in intermediate filaments. These findings emphasize the importance of segmental cell-ECM interactions in modulating cell-ECM interaction.