Abstract
Purpose:
Proliferative vitreoretinopathy (PVR) is a blinding disorder that results as a consequence of aberrant wound healing following a retinal tear or detachment. Although activation of the retinal pigmented epithelium (RPE) has been implicated in PVR, the mechanisms leading to enhanced proliferation, migration and contraction of RPE cells remains largely unknown. This study utilized an in vitro model of PVR to investigate the role of acetylation in the activation of RPE and its contribution to the progression of this disease.
Methods:
ARPE19 and induced pluripotent stem cell-derived RPE (iPS-RPE) were cultured as previously described (Muniz A, et al., IVOS 2013). Cells treated with the histone deacetylase (HDAC) inhibitor, Trichostatin A (TSA; 0.1μM) were assessed for contraction and migration via collagen contraction and scratch assays, respectively. Co-immunoprecipitation, Western blotting and immunofluorescence analysis was performed to assess α-smooth muscle actin, β-catenin and myosin IIa expression following TSA treatment alone or in the presence of histone acetyltransferase (HAT) inhibitors.
Results:
TSA (0.1μM) significantly increased contraction of ARPE19 cells in collagen matrix alone and this effect was potentiated in the presence of TGFβ-2 (10ng/μL). Moreover, co-treatment with HAT inhibitors curcumin (5μM), garcinol (5μM) and plumbagin (1μM) attenuated TSA-mediated collagen contraction. Scratch assays to investigate the contribution of acetylation on wound healing revealed TSA did not affect iPS-RPE cell migration. Immunofluorescence analysis of TSA-treated iPS-RPE wounded monolayers revealed decreased α-smooth muscle actin expression and reduced β-catenin at the plasma membrane as compared to control.
Conclusions:
Our findings indicate a role of acetylation in the activation of RPE. Specifically, the HDAC inhibitor TSA enhanced RPE cell contraction and induced β-catenin translocation to the nucleus, indicating epithelial-mesenchymal transition (EMT) activation. Further investigation of pharmacological compounds that modulate acetylation may hold potential as therapeutic agents for the treatment of PVR.