Exogenous hydrogen sulfide mitigates NLRP3 inflammasome-mediated inflammation through promoting autophagy via AMPK-mTOR pathway

Abstract

The aim of this study was to investigate whether exogenous hydrogen sulfide (H₂S) could mitigate NLRP3 inflammasome-mediated inflammation through promoting autophagy via the AMPK-mTOR pathway in L02 cells. L02 cells were stimulated with different concentrations of oleic acid (OA), then cell viability and the protein expression of NLRP3 and pro-caspase-1 were detected by MTT and western blot, respectively, to determine appropriate OA concentration in this study. The cells were divided into four groups: the cells in the control group were cultured with RPMI-1640 for 24.5 h; the cells in the OA group were cultured with RPMI-1640 for 0.5 h, then were stimulated with 1.2 mmol/l OA for 24 h; the cells in the NaHS+OA group were pretreated with sodium hydrogen sulfide (NaHS, a donor of H₂S) for 0.5 h before exposure to OA for 24 h; and the cells in the NaHS group were treated with NaHS 0.5 h, then were cultured with RPMI-1640 for 24 h. Subsequently, the cells in every group were collected and the protein expression of NLRP3, procaspase-1, cleaved caspase-1, P62, LC3, Beclin1, T-AMPK, P-AMPK, T-mTOR, P-mTOR and the level of IL-1β were detected by western blot and ElISA, respectively. Exogenous H₂S reduced the level of NLRP3, caspase-1, P62, IL-1β and the ratio of P-mTOR/T-mTOR induced by OA and increased the ratio of LC3 II/I and the protein expression of Beclin1 suppressed by OA. This study demonstrates for the first time that H₂S might suppress NLRP3 inflammasome-mediated inflammation induced by OA through promoting autophagy via the AMPK-mTOR pathway. It provides a theoretical basis for the further study of the anti-inflammatory mechanism of H₂S.