Roles of Toll-Like Receptor 4 for Cellular Pathogenesis in Primary Open-Angle Glaucoma: A potential therapeutic strategy.

In recent years, glaucoma has been proposed as an autoimmune disease and an understanding immune-regulation concept has been applied for novel glaucoma therapy. Current evidence suggests an innate immunity is a keystone step for primary open angle glaucoma (POAG) pathogenesis resulting from trabecular meshwork (TM) cell fibrosis and retinal ganglion cell (RGC) death. Toll-like receptor 4 (TLR4) is a common player in the innate immunity, which appears on the TM and RGC of POAG. The activation of TLR4 regulates several molecules involving both fibrosis and cell death. Inhibition of TLR4 decreases TGF-β2-induced fibrosis in TM cells and enhances cell survival of RGC in both optic nerve crush and ischemia models. In this review, we will summarize the molecular mechanisms of TLR4 related to POAG pathogenesis. An understanding of this mechanism may provide novel development of therapeutic strategies for POAG.