LncRNA NEAT1 accelerates renal tubular epithelial cell damage by modulating mitophagy via miR-150-5p-DRP1 axis in diabetic nephropathy

New findings: What is the central question of this study? Diabetic nephropathy (DN) is a severe complication of diabetes correlated with a higher mortality rate in diabetic patients. Renal tubular injury participates in the pathogenesis of DN. We aimed to uncover the biological function of the NEAT1-miR-150-5p-DRP1 axis in an in vitro model of DN and elaborate the potential mechanisms. What is the main finding and its importance? NEAT1 facilitated high glucose-induced damage in HK-2 cells by reducing Mitophagy via the miR-150-5p-DRP1 axis, which sheds LIGHT on DN pathogenesis and reveals a potential treatment for DN.

Abstract: Diabetic nephropathy (DN) is a severe complication in diabetic patients, with a high mortality rate. Renal tubular injury is involved in the pathogenesis of DN. In this study, we aimed to uncover the regulatory roles of the NEAT1-miR-150-5p-DRP1 axis in an in vitro model of DN and its possible mechanisms. High glucose-challenged HK-2 cells were used as an in vitro DN model. NEAT1, miR-150-5p and DRP1 levels were assessed by RT-qPCR. Cell viability was determined by the MTT assay. MitoSOX Red and JC-1 were used to evaluate intracellular production of Reactive Oxygen Species and mitochondrial membrane potential, respectively. Lactate Dehydrogenase release and superoxide dismutase activity were assessed with commercial kits. The protein levels of DRP1, p62, BECN1(beclin 1) and BNIP3 were determined by western blotting. The interaction between NEAT1 (DRP1) and miR-150-5p was verified by a dual-luciferase reporter assay and an RNA immunoprecipitation assay. Our results showed that in response to high glucose the NEAT1 and DRP1 levels were upregulated, whereas the miR-150-5p level was downregulated in HK-2 cells. Knockdown of NEAT1 or DRP1 in high glucose-challenged HK-2 cells inhibited excessive Reactive Oxygen Species production and Lactate Dehydrogenase release, increased cell viability, mitochondrial membrane potential and superoxide dismutase activity and enhanced Mitophagy. Inhibition of miR-150-5p resulted in the opposite results. Mechanistically, NEAT1 sponged miR-150-5p to increase the DRP1 level. Moreover, silencing of NEAT1 or DRP1 could counteract miR-150-5p inhibition-induced deleterious effects. Collectively, our findings indicate that NEAT1 facilitates high glucose-induced damage in HK-2 cells by suppressing Mitophagy via the miR-150-5p-DRP 1 axis, which sheds LIGHT on a novel mechanism of DN.