FGF23 Controls Myocardial Fibrosis Progression via Promoting Cardiac Fibroblast Proliferation and Activation in Mice

Heart failure (HF) is the leading cause of morbidity and mortality worldwide, while myocardial fibrosis acts as a pivotal hallmark, which exacerbates ventricular dysfunction and remodeling in HF. In this study, we found FGF23, a critical endocrine regulator, which regulates phosphate and vitamin D metabolism, was significantly upregulated in fibrotic mouse hearts after transverse aortic constriction (TAC). By using the FGF23 monoclonal antibody, we found that inhibition of FGF23 alleviated TAC-induced cardiac fibrosis, while injection of recombinant FGF23 (rFGF23) protein exacerbated tissue fibrosis in mouse hearts after TAC. RNA Sequencing indicated that FGF23 may promote cardiac fibroblast proliferation and activation in stressed mouse hearts. In human primary cardiac fibroblasts, rFGF23 treatment further upregulated the expression of Ki67, Cyclin D1, Cyclin E1, PCNA, α-SMA, and Collagen 1A1 after TGF-β stimulation. Further results indicated that FGF23 promoted cardiac fibroblast proliferation and activation through FGFR4 and activated the downstream MAPK/ERK signaling. This study suggests a role of FGF23 in the regulation of myocardial fibrosis, which shows the potential of targeting FGF23 in the treatment of HF and cardiac fibrosis.