GSK126 an inhibitor of epigenetic regulator EZH2 suppresses cardiac fibrosis by regulating the EZH2-PAX6-CXCL10 pathway

Myocardial fibrosis is a common pathological companion of various cardiovascular diseases. To date, the role of enhancer of zeste homolog 2 (EZH2) in cancer has been well demonstrated including in renal carcinoma and its inhibitors have entered the stage of phase I/II clinical trials. However, the precise mechanism of EZH2 in cardiac diseases is largely unclear. In the current study, we first found that EZH2 expression was increased in Ang-II-treated cardiac fibroblasts (CFs) and mouse heart homogenates following isoproterenol (ISO) administration for 21 days, respectively. Ang-II induces CFs activation and increased collagen-I, collagen-III, α-SMA, EZH2, and trimethylates lysine 27 on histone 3 (H3K27me3) expressions can be reversed by EZH2 inhibitor (GSK126) and EZH2 siRNA. The ISO-induced cardiac hypertrophy, and fibrosis in vivo which were also related to the upregulation of EZH2 and its downstream target, H3K27me3, could be recovered by GSK126. Furthermore, the upregulation of EZH2 induces the decrease of paired box 6 (PAX6) and C-X-C motif ligand 10 (CXCL10) "which" were also reversed by GSK126 treatment. In summary, the present evidence strongly suggests that GSK126 could be a therapeutic intervention, blunting the development and progression of myocardial fibrosis in an EZH2-PAX6-CXCL10-dependent manner.