MeCP2 epigenetically regulates alpha‐smooth muscle actin in human lung fibroblasts

Abstract

Background: A critical feature for fibroblasts differentiation into myofibroblasts is the expression of alpha-smooth muscle actin (α-SMA) during the tissue injury and repair process. The epigenetic mechanism, DNA methylation, is involved in regulating α-SMA expression. It is not clear how methyl-CpG-binding protein 2 (MeCP2) interacts with CpG-rich region in α-SMA, and if the CpG methylation status would affect MeCP2 binding and regulation of α-SMA expression.Methods: The association of MeCP2 with α-SMA CpG rich region were examined by chromatin immunoprecipitation (ChIP) assays in primary fibroblasts from idiopathic pulmonary fibrosis (IPF) and non-IPF control individuals, and in the lung fibroblasts treated with profibrotic cytokine transforming growth factor β1 (TGF-β1). The regulation of α-SMA by MeCP2 was examined by knocking down MeCP2 with small interfering RNA (siRNA).To explore the effects of the DNA methylation status of the CpG rich region on α-SMA expression, the cells were treated with DNA methyltransferase inhibitor, 5′-azacytidine (5′-aza). The expression of α-SMA was examined by Western blot and quantitative polymerase chain reaction, the association with MeCP2 was assessed by ChIP assays, and the methylation status was checked by bisulfate sequencing. Results:The human lung fibroblasts with increased α-SMA showed an enriched association of MeCP2, while knockdown MeCP2 by siRNA reduced α-SMA upregulation by TGF-β1. The 5′-Aza-treated cells have decreased α-SMA expression with reduced MeCP2 association. However, bisulfite sequencing revealed that most CpG sites are unmethylated despite the different expression levels of α-SMA after being treated by TGF-β1 or 5′-aza. Conclusion: Our data indicate that the methyl-binding protein MeCP2 is critical for α-SMA expression in human lung myofibroblast, and the DNA methylation status at the CpG rich region of α-SMA is not a determinative factor for its inducible expression.

Platelet-rich plasma accelerates skin wound healing by promoting re-epithelialization

“…In the middle and late stages, the differentiation of fibroblasts into myofibroblasts gradually increased with the formation of granulation tissue, which will drive the effective contraction of the wound margin [ 51 , 52 ]. Previous studies found that PRP treatment for wound healing resulted in a greater proportion of myofibroblasts present at the wound site by quantifying α-SMA, specifically expressed by myofibroblasts [ 53 ]. In our study, PRP could increase the secretion of α-SMA, the same as in the previous study.…”

Epigenetic Reprogramming of Tumor-Associated Fibroblasts in Lung Cancer: Therapeutic Opportunities

“…On the other hand, it was reported that the DNA-binding protein MeCP2 promotes α-SMA expression in pulmonary fibroblasts through direct binding to 3 regions within the promoter of its coding gene ACTA2, particularly when it is methylated [61,62]. Conversely, forced MeCP2 downregulation markedly reduced pulmonary fibrosis and fibroblast activation in an in vivo model [61].…”

Epigenetic Changes and Functions in Pneumoconiosis

“…MeCP2 is essential for myofibroblast differentiation and lung fibrosis. Xiang et al [ 42 ] found that MeCP2 was correlated with ACTA2 expression in primary IPF fibroblasts through a chip experiment. MeCP2 plays a key role in the upregulation of ACTA2 by transforming growth factor β (TGF- β ) in lung fibroblasts, and 5-azaC can partially block the expression of ACTA2 induced by TGF- β [ 42 ].…”

“…Xiang et al [ 42 ] found that MeCP2 was correlated with ACTA2 expression in primary IPF fibroblasts through a chip experiment. MeCP2 plays a key role in the upregulation of ACTA2 by transforming growth factor β (TGF- β ) in lung fibroblasts, and 5-azaC can partially block the expression of ACTA2 induced by TGF- β [ 42 ]. Although DNMTs inhibitors have been widely used for treatment, their disadvantages are obvious.…”