Cordycepin from Cordyceps militaris ameliorates diabetic nephropathy via the miR-193b-5p/MCL-1 axis

BACKGROUND: Diabetic nephropathy (DN) is a chronic kidney disease that develops in patients with diabetes mellitus. Cordycepin (CRD), a secondary metabolite produced by Cordyceps militaris, has a variety of bioactive properties. In this study, DN mice and high glucose (HG)-treated HK-2 were used to evaluate the diagnostic value of CRD. METHODS: Quantitative real-time PCR (qRT-PCR), western blotting, immunofluorescence analysis, and immunohistochemical staining were used to assess changes in mRNA and protein expression. Oxidative stress was evaluated by detecting the production of reactive oxygen species (ROS) and the activity of antioxidant enzymes. Cell apoptosis was detected by the TUNEL and flow cytometric methods. The interaction of miR-193b-5p and myeloid leukemia 1 (MCL-1) was examined by bioinformatics analysis and luciferase reporter assay. The protective effects of CRD on DN mice were evaluated by examining DN related biochemical indicators and renal histopathology. RESULTS: In response to HG, the level of miR-193b-5p was elevated, whilst the level of MCL-1 was downregulated, and CRD therapy reversed this behavior. MCL-1 was further identified to be miR-193b-5p target. CRD attenuated HG-induced cell damage, inflammation and abnormal energy metabolism. Mechanistic investigations on in vitro models confirmed that protective effect of CRD against HG challenge to HK-2 cells is mediated through the regulation of expression of miR-193b-5p/MCL-1 axis. By examining DN related biochemical markers and renal histopathology, the protective effects of CRD on DN mice was assessed. CONCLUSIONS: In summary, CRD decreased oxidative stress and inflammation by increasing miR-193b-5p and inactivating downstream MCL-1 in DN, hinting the pivotal values of CRD and miR-193b-5p in the management of DN. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13020-023-00842-5.