[Inhibition of miR-30d-5p promotes mitochondrial autophagy and alleviates high glucose-induced injury in podocytes].

Objectives: To study the role of microRNA (miR)-30d-5p in high glucose-induced podocyte injury.

Methods: Podocytes were hyperglycated with 30 mmol/L glucose, transfected with miR-30d-5p inhibitor and mimic, and then treated with 1 mg/mL 3-methyladenine (3-MA). The transfection efficiency of miR-30d-5p was quantified by reverse transcription PCR. Apoptosis was detected by flow cytometry. The expressions of nephrin, microtubule-associated protein light chain (LC) 3Ⅱ/LC3Ⅰ, P62, autophagy-related gene (ATG) 5, PTEN induced putative kinase (PINK) 1 and Parkin gene (PARK2) were detected by Western blotting. The mito-chondrial membrane potential was detected by JC-1 fluorescent probe, and adenosine triphosphate (ATP) content in cells was detected by relevant kits.

Results: Under high glucose induction, podocyte apoptosis increased, miR-30d-5p and P62 expressions were upregulated, while nephrin, ATG5, PINK1, PARK2 and LC3Ⅱ/LC3Ⅰ expressions decreased (all P<0.01). MiR-30d-5p inhibitor reversed the effect of high glucose on apoptosis, and the expression of ATG5, PINK1, PARK2, nephrin, LC3Ⅱ/LC3Ⅰ and P62 (all P<0.01). High glucose induced loss of mitochondrial membrane potential and ATP content in podocytes, while inhibition of miR-30d-5p increased them. Autophagy inhibitors 3-MA and miR-30d-5p mimics reversed the effects of miR-30d-5p inhibition on apoptosis, autophagy and mitochondrial function of podocytes induced by high glucose (all P<0.05).

Conclusions: Inhibition of miR-30d-5p may promote mitochondrial autophagy (mitophagy) by promoting the expression of ATG5, PINK1, PARK2 and alleviating high glucose-induced podocyte damage.