Long noncoding RNA MALAT1 regulates renal tubular epithelial pyroptosis by modulated miR-23c targeting of ELAVL1 in diabetic nephropathy

Diabetic nephropathy is a common kidney condition in patients with diabetes mellitus, which can result in renal failure. Pyroptosis, the process of pro-inflammatory programmed cell death, plays an important role in the pathogenesis of this disease. Long non-coding RNA MALAT1 has also been shown to be involved in diabetic nephropathy. Here, we investigated the role of MALAT1 and the microRNA miR-23c and its target gene ELAVL1 in renal tubular epithelial cells. Our data demonstrated that MALAT1 expression was substantially increased but miR-23c was decreased in streptozotocin-induced diabetic rats and in high-glucose-treated HK-2 cells. Downregulation of MALAT1 or upregulation the expression of miR-23c inhibited pyroptosis in HK-2 cells. In an effort to understand the signaling mechanisms underlying the pro-pyroptotic properties of MALAT1 and the anti-pyroptotic properties of miR-23c, we found that inhibiting the expression of MALAT1 downregulated the expression of ELAVL1, NLRP3, Caspase-1 and the pro-inflammatory cytokine IL-1f3. These findings were replicated by upregulation of miR-23c. Moreover, luciferase assays showed that miR-23c, as a target of MALAT1, directly repressed ELAVL1 expression and then decreased the expression of its downstream protein NLRP3. The expression of MALAT1 antagonized the effect of miR-23c on the downregulation of its target ELAVL1 and inhibited hyperglycemia-induced cell pyroptosis. This mechanism may contribute to a better understanding of diabetic nephropathy pathogenesis and facilitate the development of new therapeutic strategies for the treatment of this disease.