CD226 promotes renal fibrosis by regulating macrophage activation and migration

Abstract

It has been found that CD226 plays an important role in regulating macrophage function, but its expression and function on macrophage during renal fibrogenesis have not been studied. Our data demonstrated that CD226 expression in macrophages was obviously upregulated in the UUO model, while CD226 deficiency attenuated collagen deposition in renal inerestitum along with fewer number of M1 within renal cortex and renal medulla and a lower level of proinflammatory factors compared to control littermates. Further studies demonstrated that Cd226-/–BMDMs transferring to Cd226+/+ mice could significantly reduce the tubular injury, collagen deposition and proinflammatory cytokines secretion compared with WT-BMDMs group and WT-PBS group in adoptively transferring assay. Mechanistic investigations revealed that CD226 could suppress KLF4 expression in macrophages, which subsequently promoted more proinflammatory M1 accumulation in the kidney of WT mice than that of CD226 deficient mice. In vitro, we silenced KLF4 expression in BMDMs deriving from WT or CD226 deficient mice and the trend that CD226 promting more numbers of M1 disappeared. Therefore, our results uncover a pathogenic role of CD226 during the development of CKD by promoting monocyte infiltration from peripheral blood into the kidney and enhancing macrophage activation towards to the inflammatory phenotype by suppressing KLF4 expression.