P-MeCP2-421 is a critical mediator of the pathogenesis of proliferative vitreoretinopathy

Abstract

Purpose : Proliferative vitreoretinopathy (PVR) is a blinding eye disease. The pathogenesis of PVR is still under investigation. In the current study, we sought to investigate the role of the methyl-CpG-binding protein 2(MeCP2) especially phosphorylated P-MeCP2-421 (P-MeCP2-421) in the pathogenesis of PVR.

Methods : The expressions of P-MeCP2-421, P-MeCP2-80, PPAR-γ and the double labeling of P-MeCP2-421 with α-SMA, cytokeratin, TGF-β, GFAP and PPAR-γ in human PVR membranes were analyzed by immunohistochemistry. The effect of knocking down MeCP2 using siRNA on the expressions of α-SMA, phospho-Smad2/3, collagen I, fibronectin and PPAR-γ was studied by western blot in cultured ARPE-19. The expression of α-SMA stimulated by recombinant MeCP2 and P-MeCP2-421 activation by TNFα in the cells was evaluated using western bot. The effect of TGF-β and 5-AZA treatment on PPAR-γ expression was analyzed by western blot as well. Chromatin immunoprecipitation was used to determine the binding of MeCP2 to TGF-β.

Results : Our results showed that P-MeCP2-421 was highly expressed in PVR membranes and was double labeled with cells positive for α-SMA, cytokeratin, GFAP and TGF-β, knock-down MeCP2 inhibited the activation of Smad2/3 and the expression of collagen 1 and fibronectin induced by TGF-β. TGF-β inhibited the expression of PPAR-γ, silence of MeCP2 by siRNA or using MeCP2 inhibitor (5-AZA) increased the expression of PPAR-γ. α-SMA was upregulated by the treatment of recombinant MeCP2. TNFα stimulated the activation of P-MeCP2-421. Importantly, we found that MeCP2 binded to TGFβ as demonstrated by Chip assay.

Conclusions : The results from current study suggest that MeCP2 especially phosphorylated P-MeCP2-421 may play a significant role in the pathogenesis of PVR and targeting MeCP2 may be a potential of therapeutical approach for the treatment of PVR.

This is a 2020 ARVO Annual Meeting abstract.