IKKα aggravates renal fibrogenesis by positively regulating the Wnt/β-catenin pathway.

AKI (acute kidney injury) with maladaptive repair plays exacerbated role in renal fibrosis characterized by tubulointerstitial fibrosis. Previously, we reported that IKKα contributed to kidney regeneration and inhibited inflammation. Here, we first identified the role and mechanism of IKKα on TGF-β1-induced fibrosis in human tubular epithelial cells and fibrotic kidneys. IKKα was up-regulated in kidney tubular epithelium in unilateral ureteral obstruction (UUO) and unilateral ischemic reperfusion injury (UIRI) mice. Immunohistochemical staining showed that IKKα was positively correlated with the extent of kidney fibrosis in tissue biopsies from chronic kidney disease (CKD) patients. Compared with wild-type controls, Ksp-IKKα -/- mice exhibited inactivated Wnt/β-catenin pathway, decreased serum creatinine and interstitial fibrosis in the kidney after IRI. In TGF-β1-stimulated human tubular epithelial cells, IKKα overexpression enhanced β-catenin nuclear translocation. Blocking IKKα by siRNA specifically suppressed β-catenin activation and downstream profibrotic genes such as fibronectin and α-smooth muscle actin (α-SMA). Taken together, our study demonstrated that IKKα aggravated renal fibrogenesis by activating Wnt/β-catenin signalling pathway, providing a new target for the treatment of kidney fibrosis.