Methyl-CpG-binding domain protein 2 contributes to renal fibrosis through promoting polarized M1 macrophages

Recent studies reported that Methyl-CpG–binding domain protein 2 (MBD2) promoted M2 macrophages accumulation to increase bleomycin-induced pulmonary fibrosis. However, the role and mechanism of action of MBD2 in macrophages differentiation and renal fibrosis remain largely unknown. In the current study, MBD2 not only promoted the differentiation of resting M0 macrophages to polarized M2 macrophages, but also induced them to polarized M1 macrophages and the transition of M2 to M1 macrophages. ChIP analysis demonstrated that MBD2 physically interacted with the promoter region of the CpG islands of G0S2 genes, and then activated their expression by inducing hypomethylation of the promoter region. Interestingly, the data demonstrated that the role of G0S2 in macrophages differentiation is consistent with MBD2. Furthermore, Co-culture of activated M1 macrophages and murine embryonic NIH 3T3 fibroblasts indicated that MBD2 mediated the M1-induction of ECM production by embryonic NIH 3T3 fibroblasts via promotion of G0S2. In addition, we also found that inhibition of MBD2 suppressed LPS induced the expression of p53 as well as activation and expression of stat3 in RAW264.7 macrophages. In vivo, MBD2 LysM(cre) attenuated unilateral ureteral obstruction (UUO) and ischemia/reperfusion (I/R)-induced renal fibrosis via downregulation of G0S2, which was demonstrated by the downregulation of fibronectin (FN), collagen I and IV, α-SMA, G0S2. These data collectively demonstrated that MBD2 in macrophages contributed to UUO and I/R-induced renal fibrosis through the upregulation of G0S2, which could be a target for treatment for chronic kidney disease.