A protective role of nintedanib in peritoneal fibrosis through H19-EZH2-KLF2 axis via impeding mesothelial-to-mesenchymal transition.

Abstract

Peritoneal fibrosis (PF), a common complication of long-term peritoneal dialysis, accounts for peritoneal ultrafiltration failure to develop into increased mortality. Nintedanib has previously been shown to protect against multi-organ fibrosis, including PF. Unfortunately, the precise molecular mechanism underlying nintedanib in the pathogenesis of PF remains elusive. The mouse model of PF was generated by chlorhexidine gluconate (CG) injection with or without nintedanib administration, either with the simulation for the cell model of PF by constructing high-glucose (HG)-treated human peritoneal mesothelial cells (HPMCs). HE and Masson staining were applied to assess the histopathological changes of peritoneum and collagen deposition. FISH, RT-qPCR, western blot and immunofluorescence were employed to examine distribution or expression of targeted genes. Cell viability was detected using CCK-8 assay. Cell morphology was observed under a microscope. RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays were applied to validate the H19-EZH2-KLF2 regulatory axis. Aberrantly overexpressed H19 was observed in both the mouse and cell model of PF, of which knockdown significantly blocked HG-induced mesothelial-to-mesenchymal transition (MMT) of HPMCs. Moreover, loss of H19 further strengthened nintedanib-mediated suppressive effects against MMT process in a mouse model of PF. Mechanistically, H19 could epigenetically repressed KLF2 via recruiting EZH2. Furthermore, TGF-β/Smad pathway was inactivated by nintedanib through mediating H19/KLF2 axis. In summary, nintedanib disrupts MMT process through regulating H19/EZH2/KLF2 axis and TGF-β/Smad pathway, which laid the experimental foundation for nintedanib in the treatment of PF.