Systemic administration of miR-451 improves autophagy response in an accelerated mouse model of diabetic kidney disease
Authors: Agbor-Baiyee Baiyeendang , Obiwuma Chidera , Mohit Neal , Gambhir Kanwal , Ecelbarger Carolyn , Fluitt Maurice 
Published: May 2024

Diabetic kidney disease (DKD) is a common and severe microvascular complication of both type 1 and type 2 diabetes mellitus. It is the most common cause of end stage renal disease in the United States. Autophagy is a highly conserved pathway that recycles damaged organelles and macromolecules to maintain intracellular homeostasis. There is mounting evidence highlighting the role of autophagy in diabetic kidney disease. MicroRNAs (miRNA) affect the transcription of several genes involved in the development and progression of DKD, regulating key pathways and processes, including fibrotic signaling and autophagy. Thus, the dysregulation of miRs exacerbates kidney injury in the diabetic setting. Previous work from our group suggests that chronic systemic inhibition of miR-451 exacerbates fibrosis in the kidney of an obese insulin resistant mouse model (tallyHo/Jng), indicating a potential renoprotective role for miR-451 in the diabetic kidney. However, few studies have investigated this protective role of miR-451 in the diabetic kidney. This study aimed to understand the renoprotective effects of miR-451 in an accelerated mouse model of DKD. BTBR ob/ob mice rapidly develop morphological renal lesions characteristic of both early and advanced human DKD, with proteinuria typically beginning at 4-weeks of age. 12-week old male black and tan, brachyuric (BTBR) ob/ob mice and BTBR wild-type mice were treated with commercially available miR-451 mimics (2mg/kg/bw; n=3/treatment group; treatment groups: WT, BTBR ob/ob, WT+miR-451, and BTBR ob/ob+miR-451) 1X per week for 3-consective weeks. Spot urine was collected weekly until the end of study. Random blood glucose was measured by tail prick weekly. Mice were humanely euthanized, and kidneys and blood harvested at the end of the treatment period. Western blotting of whole kidney homogenate was performed following a standard protocol. Data was analyzed using students t-test or ANOVA, where appropriate, p<0.05 considered significant. Albumin: creatinine ratio was four times higher (p=0.01) in BTBR ob/ob mice beginning at 5 weeks. Treatment with miR-451 mimics had no significant effect on body weight in either group. Blood glucose was significantly higher in miR-451 treated and untreated BTBR ob/ob mice at 12-weeks (425± 33.1 mg/dL; p=0.04) and 13-weeks (383± 25.3 mg/dL; p=0.007). However, blood glucose decreased significantly from week 13 (554.7± 10.8 mg/dL) to week 14(289± 13.3 mg/dL; p=0.0002) in BTBR ob/ob miR-451 treated mice. Western blot analysis of MiR-451 mimic treated BTBR ob/ob and WT mice whole kidney homogenate revealed a 91% (p=0.02) and 95% (p=0.01) reduction, respectively, in YWHAZ (a predicted miR-451 target). Conversely, western blot analysis of autophagy related proteins revealed a 68% (p=0.01) increase in ATG101 and a 44% increase in Beclin-1 in miR-451 mimic treated BTBR ob/ob mice. Collectively, the findings of this study suggest that miR-451 may offer protection in the diabetic kidney via autophagic signaling and improved blood glucose control. GHUCCTS KL2 Scholar Program (Award Number: KL2TR001432) The Charles and Mary Latham Fund Howard University Department of Medicine Start-Up Funds; Howard University Bridge Fund and Pilot Study Awards. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.