LncRNA GAS5 inhibits miR-579-3p to activate SIRT1/PGC-1α/Nrf2 signaling pathway to reduce cell pyroptosis in sepsis-associated renal injury

Sepsis is a life-threatening condition that can lead to several organ failures including kidney. In this study, we investigated the roles of GAS5 and miR-579-3p in regulating cell pyroptosis in the sepsis-induced renal injury model. Lipopolysaccharide (LPS) treatment or cecal ligation and puncture (CLP) surgery was used to create the in vitro and in vivo sepsis-induced renal injury model. The interactions between GAS5 and miR-579-3p, miR-579-3p and SIRT1 were determined by bioinformatic prediction, luciferase reporter assay and RIP assay. In vitro cell pyroptosis was examined by flow cytometry marked with active caspase-1 and PI. The protein levels of IL-1β and IL-18 induced by cell pyroptosis were quantified using ELISA assay. In vivo renal injuries were evaluated with HE and TUNEL stainings, bacterial load in serum and creatinine and blood urea nitrogen content analyses. Expression levels of GAS5, miR-579-3p, pyroptosis and SIRT1/PGC-1a/Nrf2 pathway-related molecules were evaluated by qRT-PCR or western blot. GAS5 and SIRT1 were downregulated while miR-579-3p was upregulated in in vitro and in vivo sepsis-induced renal injury models. GAS5 negatively and directly regulated miR-579-3p to reduce cell pyroptosis via activation of SIRT1/PGC-1a/Nrf2 pathway. In addition, miR-579-3p suppressed PGC-1a/Nrf2 pathway to induce cell pyroptosis by directly targeting SIRT1. What's more, overexpression of GAS5, or knockdown of miR-579-3p, enhanced SIRT1 expression that led to the improved survival rate, reduced the weight loss, and relieved renal injuries in septic mice. Overexpression of GAS5 demonstrated protective effects against sepsis-induced renal injury via downregulating miR-579-3p and activating SIRT1/PGC-1α/Nrf2 pathway to inhibit cell pyroptosis.