Inhibition of DNA methylation and methyl-CpG-binding protein 2 suppresses RPE transdifferentiation: Relevance to proliferative vitreoretinopathy

Shikun He, Ernesto Barron, Keijiro Ishikawa, Hossein Nazari Khanamiri, Chris Spee, Peng Zhou, Satoru Kase, Zhuoshi Wang, Laurie Diane Dustin, David R. Hinton

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

PURPOSE. The purpose of this study was to evaluate expression of methyl-CpG-binding protein 2 (MeCP2) in epiretinal membranes from patients with proliferative vitreoretinopathy (PVR) and to investigate effects of inhibition of MeCP2 and DNA methylation on transforming growth factor (TGF)-β–induced retinal pigment epithelial (RPE) cell transdifferentiation. METHODS. Expression of MeCP2 and its colocalization with cytokeratin and a-smooth muscle actin (α-SMA) in surgically excised PVR membranes was studied using immunohistochemistry. The effects of 5-AZA-2′-deoxycytidine (5-AZA-dC) on human RPE cell migration and viability were evaluated using a modified Boyden chamber assay and the colorimetric 3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. Expression of RASAL1 mRNA and its promoter region methylation were evaluated by real-time PCR and methylationspecific PCR. Effects of 5-AZA-dC on expression of α-SMA, fibronectin (FN), and TGF-β receptor 2 (TGF-β R2) and Smad2/3 phosphorylation were analyzed by Western blotting. Effect of short interfering RNA (siRNA) knock-down of MeCP2 on expression of α-SMA and FN induced by TGFβ was determined. RESULTS. MeCP2 was abundantly expressed in cells within PVR membranes where it was double labeled with cells positive for cytokeratin and α-SMA. 5-AZA-dC inhibited expression of MeCP2 and suppressed RASAL1 gene methylation while increasing expression of the RASAL1 gene. Treatment with 5-AZA-dC significantly suppressed the expression of α-SMA, FN, TGF-β R2 and phosphorylation of Smad2/3 and inhibited RPE cell migration. TGF-β induced expression of α-SMA, and FN was suppressed by knock-down of MeCP2. CONCLUSIONS. MeCP2 and DNA methylation regulate RPE transdifferentiation and may be involved in the pathogenesis of PVR.

Original languageEnglish
Pages (from-to)5579-5589
Number of pages11
JournalInvestigative Ophthalmology and Visual Science
Volume56
Issue number9
DOIs
Publication statusPublished - Jan 1 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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