Abstract
Purpose:
Traction retinal detachment (TRD) is the major complication of proliferative vitreoretinopathy (PVR) that is caused by contraction of epiretinal membranes, derived from retinal pigment epithelial (RPE) and Müller cells.We have previously reported that dasatinib, a FDA-approved tyrosine kinase inhibitor, can inhibit matrix contraction by both cell types without detectable toxicity. In this study, we examined the mechanism of dasatinib inhibition of matrix contraction caused by Muller cells.
Methods:
Müller cells were isolated from porcine eyes using a papain/DNase kit, and used between passages 3-6. Type I collagen matrix contraction assays were used to examine the effect of drugs on contraction. Fluophore-conjugated phalloidin was used for the detection of actin cytoskeleton in these cells. Western-blot analyses were carried out to examine protein expression and phosphorylation status.
Results:
As previously reported, dasatinib significantly inhibited matrix contraction by Müller cells. Dasatinib treatment led to decreased cell spreading and reduction of actomyosin stress fibers. Concomitantly, dasatinib-treated Müller cells had reduced phosphorylation of Src family kinase, paxillin, as well as myosin II light chain. Specific inhibitors of Rho/ROCK and myosin II confirmed the critical role played by this pathway on Müller cell contraction.
Conclusions:
Our data demonstrate that dasatinib inhibits matrix contraction by Müller cells via interference with focal adhesion, as well as actomyosin contraction.