521-P: Sodium Butyrate Alleviates High-Glucose-Induced Renal Glomerular Endothelial Cells Pyroptosis

Caspase1-GSDMD canonical pyroptosis pathway is associated with pathogenesis of chronic inflammatory diseases. As the first layer of renal filtration barrier, whether high glucose triggers glomerular endothelial cells (GECs) pyroptosis in the pathogenesis of diabetic nephropathy (DN) is unclear. Previous research showed that the gut microbiota metabolites-butyrate, reversed high glucose induced IL-1β release in mesangial cells. However, the effects of butyrate on pyroptosis in GECs remain indistinct. Therefore, we hypothesized that high glucose may induce GECs pyroptosis and then trigger inflammatory, but sodium butyrate may alleviate it. In this study, human renal glomerular endothelial cells (HRGECs) were exposed to high glucose in vitro, exogenous sodium butyrate was used as an intervention reagent, and then caspase 1 inhibitor Ac-YVAD-CMK pre-treated or silencing GSDMD by siRNA on HRGECs. The expression of Caspase1-GSDMD signaling molecule were observed by confocal microscopy and western blotting. Propidium iodide (PI) staining-positive cells were determined using a flow cytometer. The release of IL-1β was detected and the release of lactate dehydrogenase (LDH) was assayed. Our results showed that high glucose increased the protein level of GSDMD, GSDMD-N and cleaved-caspase-1, and induced the release of IL-1β and LDH, PI positive staining cells also increased synchronously. Sodium butyrate co-treated, pretreatment with caspase-1 inhibitor or GSDMD siRNA alleviated high glucose-induced pyroptosis in HRGECs, respectively. Moreover, sodium butyrate-mediated anti-pyroptosis effect was facilitated by si-GSDMD. Overall, this is the first observation of the potential relationship between sodium butyrate and pyroptosis in the pathogenesis of DN, proved that sodium butyrate could inhibit high glucose-induced Caspase1-GSDMD canonical pyroptosis pathway, which may act as new therapeutic targets of DN.