Activation of Prostaglandin FP and EP2 Receptors Differently Modulates Myofibroblast Transition in a Model of Adult Primary Human Trabecular Meshwork Cells

Abstract

PURPOSE. Prostaglandin F2a analogues are the first-line medication for the treatment of ocular hypertension (OHT), and prostanoid EP2 receptor agonists are under clinical development for this indication. The goal of this study was to investigate the effects of F prostanoid (FP) and EP2 receptor activation on the myofibroblast transition of primary trabecular meshwork (TM) cells, which could be a causal mechanism of TM dysfunction in glaucoma.METHODS. Human primary TM cells were treated with either latanoprost or butaprost and TGFb2. Trabecular meshwork contraction was measured in a three-dimensional (3D) TM cellpopulated collagen gel (CPCG) model. Expression of a-smooth muscle actin (a-SMA) and phosphorylation of myosin light chain (MLC) were determined by Western blot. Assembly of actin stress fibers and collagen deposition were evaluated by immunocytochemistry. Involvement of p38, extracellular signal-regulated kinase (ERK), and Rho-associated kinase (ROCK) pathways as well as matrix metalloproteinase activation was tested with specific inhibitors.RESULTS. In one source of validated adult TM cells, latanoprost induced cell contraction as observed by CPCG surface reduction and increased actin polymerization, a-SMA expression, and MLC phosphorylation, whereas butaprost inhibited TGF-b2-induced CPCG contraction, actin polymerization, and MLC phosphorylation. Both agonists inhibited TGF-b2-dependent collagen deposition. The latanoprost effects were mediated by p38 pathway.CONCLUSIONS. Latanoprost decreased TM collagen accumulation but promoted a contractile phenotype in a source of adult TM cells that could modulate the conventional outflow pathway. In contrast, butaprost attenuated both TM contraction and collagen deposition induced by TGF-b2, thereby inhibiting myofibroblast transition of TM cells. These results open new perspectives for the management of OHT.

Autoantigens in the trabecular meshwork and glaucoma‐specific alterations in the natural autoantibody repertoire

“…Fibrosis also involves an accumulation of ECM, which was also observed in the glaucomatous TM . The hypothesis of an involvement of fibrotic processes in POAG‐related modulations of TM that could be mediated by increased levels of transforming growth factor β2 (TGFβ2) in the aqueous humour has already been discussed . The MCODE cluster of AAbs potentially reflects POAG‐specific alterations of the PDGFRB pathway.…”

“…48 The hypothesis of an involvement of fibrotic processes in POAG-related modulations of TM that could be mediated by increased levels of transforming growth factor b2 (TGFb2) in the aqueous humour has already been discussed. 49,50 The MCODE cluster of AAbs potentially reflects POAG-specific alterations of the PDGFRB pathway. However, a causative or synergetic effect of these AAbs in mediating autoimmune-driven fibrosis in glaucomatous TM cannot be excluded.…”

Prostaglandin FP receptor antagonists: discovery, pharmacological characterization and therapeutic utility

“…In studying the cellular actions of FP receptor and EP 2 receptor agonists in h‐TM cells, Kalouche et al . () showed that latanoprost‐free acid prevented collagen accumulation and contracted TM cells, both processes being antagonized by AL‐8810. In contrast, the EP 2 receptor agonist, butaprost, relaxed TM cells and reduced collagen deposition induced by TGFβ2 .…”

Open-angle glaucoma: therapeutically targeting the extracellular matrix of the conventional outflow pathway

“…Relaxation of TM cells as a result of a reduction of actin stress fibers and vinculin localization at focal adhesions was observed using such analogs [171]. Interest is increasing in the development of EP 2 and EP 4 receptor agonists for the treatment of POAG, with one such EP 2 agonist having been shown to reduce IOP by increasing both unconventional and conventional flow, facilitated by the relaxation of SC and by decrease in contractility and collagen deposition at the TM [172][173][174]. These effects are similar to those of traditional FP receptor agonists, however these, in contrast, may increase TM contractility.…”