FoxM1 promotes Wnt/ß-catenin pathway activation and renal fibrosis via transcriptionally regulating multi-Wnts expressions.

ABSTRACT

The activation of Wnt/ß-catenin pathway plays a pivotal role in promoting renal fibrosis. The activation of Wnt/ß-catenin pathway relies on the binding of Wnts to Frizzled receptors on cell membrane. However, the factor regulating Wnts production remains unclear. Here, we demonstrated that transcriptional factor FoxM1 was significantly increased in obstructed kidneys and patients' kidneys with fibrosis. The up-regulation of FoxM1 mainly distributed in tubular epithelial cells. Pharmacological inhibition of FoxM1 down-regulated multi-Wnts elevation in UUO mice and attenuated renal fibrosis. In cultured renal tubular epithelial cells, overexpression of FoxM1 promoted 8 Wnts expression, while knock-down on FoxM1-suppressed multi-Wnts including Wnt1, Wnt2b and Wnt3 expression induced by Ang II. Chromatin immunoprecipitation PCR confirmed that FoxM1 bound to Wnt1, Wnt2b, Wnt3 promoters and luciferase assay further identified that the transcriptions of Wnt1, Wnt2b and Wnt3 were regulated by FoxM1. Thus, our findings show that multi-Wnt family members were regulated by transcriptional factor FoxM1. FoxM1 might be a key switch for activating ß-catenin pathway and renal fibrosis. Therefore, FoxM1 might be a potential therapeutic target in manipulating renal fibrosis.