Abstract
Diabetic nephropathy (DN) is a common chronic microvascular complication of diabetes, characterized by the deposition of extracellular matrix (ECM) proteins. Zinc finger E-box binding homeobox 1 antisense 1 (ZEB1-AS1) has been implicated in kidney fibrosis of human DN. Here, we further explored the detailed molecular mechanism of ZEB1-AS1 in renal fibrosis in DN. The expression of ZEB1-AS1 was monitored using a quantitative real-time polymerase chain reaction. Blood glucose concentrations of mice were measured using a fast blood glucose meter. The high-performance liquid chromatography method was used to measure the serum creatinine level. Western blot analysis was used to detect the protein level of α-smooth muscle actin (α-SMA), fibronectin, collagen I, collagen IV and MAFB. The level of urine albumin was detected using the BCG (Bromocresol Green) albumin assay kit. The interaction between ZEB1-AS1, miR-217 and MAFB was investigated via the luciferase reporter and RNA immunoprecipitation analysis. Decreased ZEB1-AS1 expression in DN patients and db/db diabetic mice as well as in high glucose (HG)-induced HK-2 cells was detected. Reduction in the α-SMA, fibronectin, collagen I and IV protein expression, induced by the overexpressed ZEB1-AS1, was found in db/db diabetic mice and HG-induced HK-2 cells. In addition, we discovered that ZEB1-AS1 directly targeted miR-217, and MAFB was the target of miR-217; thus, ZEB1-AS1 might regulate the MAFB expression by targeting miR-217. Furthermore, functional experiments indicated that overexpressed ZEB1-AS1 might have decreased the accumulation of ECM proteins in the HG-induced HK-2 cells by regulating the miR-217 and MAFB expression. Overexpressed ZEB1-AS1 may inhibit renal fibrosis in diabetic nephropathy by regulating the miR-217/MAFB axis, identifying novel therapeutic targets for renal fibrosis in diabetic nephropathy.