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.