Microglial and neuronal cell pyroptosis induced by oxygen-glucose deprivation/reoxygenation aggravates cell injury via activation of the caspase-1/GSDMD signaling pathway

Background: Pyroptosis is a new type of programmed cell death, which induces a strong pro-inflammatory reaction. However, the mechanism of pyroptosis after brain ischemia/reperfusion (I/R) and the interaction between different neural cells are still unclear. This study comprehensively explored the mechanisms and interactions of microglial and neuronal pyroptosis in the simulated I/R environment in vitro. Methods The BV2 and HT22 cells were treated by oxygen-glucose deprivation/reoxygenation (OGD/R). The pyroptotic cells were detected by dye uptake method. The expression levels of pyroptotic-related proteins were determined by western blotting, immunofluorescence and enzyme linked immunosorbent assay. The cell viability was assessed using MTT assay Kit. AC-YVAD-CMK, necrosulfonamide and the siRNA of Gasdermin D (GSDMD) were used to observe the inhibited effect on caspase-1 and GSDMD, respectively. A transwell co-culture model was applied to observe pyroptosis and interactions between BV2 and HT22 cell after OGD/R. Results Both BV2 and HT22 cells underwent pyroptosis after OGD/R, and the pyroptosis occurred at earlier time point in HT22 than that of BV2. Caspase-11 and Gasdermin E (GSDME) expression in BV2 and HT22 cells did not change significantly after OGD/R. Inhibition of caspase-1 or GSDMD activity, or down-regulation of GSDMD expression, alleviated pyroptosis in both BV2 and HT22 cells after OGD/R. Transwell studies further showed that OGD/R-treated HT22 or BV2 cells aggravated pyroptosis of adjacent non-OGD/R-treated cells, which could be relieved by inhibition of caspase-1 or GSDMD. Conclusions OGD/R induces pyroptosis of microglia and neuronal cells and aggravates cell injury via activation of caspase-1/GSDMD signaling pathway. Our findings suggest that caspase-1 and GSDMD may be therapeutic targets after cerebral I/R. Necrosulfonamide, a chemical inhibitor of GSDMD, may be a potential drug to prevent cerebral I/R-induced brain injury.