MicroRNA-451 Modulates Autophagy-Related Signaling with Relevance to Renal Fibrosis in an Accelerated Mouse Model of Diabetic Kidney Disease.

BACKGROUND: Diabetic nephropathy is characterized by metabolic dysregulation, renal fibrosis, and impaired autophagy. MicroRNA-451 (miR-451) has been implicated in metabolic and stress-response pathways, but its role in diabetic kidney disease remains unclear. This study examined the effects of systemic miR-451 overexpression on renal injury and autophagy in BTBR ob/ob mice. METHODS: Wild-type (WT) and BTBR ob/ob (OB) mice were treated with miR-451 mimics. Body weight, blood glucose, and urine albumin were assessed for three consecutive weeks. Renal miR-451 expression was measured by qRT-PCR, while protein levels of YWHAZ, mTOR, and autophagy markers were analyzed by Western blotting. Renal fibrosis was evaluated using Masson's trichrome staining. RESULTS: OB mice exhibited increased body weight, hyperglycemia, and albuminuria compared with WT controls. miR-451 treatment resulted in robust renal overexpression of miR-451 in OB treated mice (8.4-fold, p = 0.039) but did not normalize metabolic parameters. miR-451 overexpression significantly reduced renal expression of YWHAZ and mTOR. Histological analysis revealed increased glomerular fibrosis in OB mice, which was significantly attenuated following miR-451 treatment in WT-treated and OB-treated mice. In addition, miR-451 treatment increased expression of autophagy-related proteins ATG101 and Beclin-1 and reduced the LC3-II/I ratio, indicating altered autophagic signaling. CONCLUSIONS: miR-451 overexpression attenuates renal fibrosis and modulates autophagy-associated pathways in diabetic kidney disease, independent of metabolic control, highlighting miR-451 as a potential therapeutic target for diabetic kidney disease.