HOXA2 exerts anti-renal fibrosis effects through reducing endoplasmic reticulum stress via the upregulation of SIRT1.

Relieving renal fibrosis are promising therapeutic strategies for chronic kidney disease (CKD). Here we showed that decreased homeobox A2 (HOXA2) expression with excessive ER stress activation were observed in the renal tissues of UUO mice established on male C57BL/6 mice and TGF-β1-induced human proximal tubular epithelial cells (HK-2 cells). After transfected HOXA2 overexpression plasmids into HK-2 cells and administered adeno-associated virus (AAV) containing HOXA2 to UUO mice, the expression of ER stress markers such as ATF6, GRP78 and CHOP decreased, renal dysfunction and fibrosis were significantly attenuated. Mechanistically, HOXA2 binds to the SIRT1 promoter, enhancing SIRT1 transcription and deacetylase activity, which led to ATF6 deacetylation and downregulation. The protective effect of HOXA2 was confirmed against the ER stress agonist thapsigargin. Moreover, DNMT1-mediated promoter methylation was identified as a potential mechanism for HOXA2 suppression in fibrosis. Targeting HOXA2 maybe an innovative therapeutic strategy for fibrosis treatment in CKD.