1,25(OH)2D3 promotes insulin secretion in Min6 cells through the canonical pyroptosis pathway

• 1、Center of Laboratory Animal, Medical College of Soochow University, Suzhou, China, 215000

Abstract：In this paper we explore the mechanism of 1,25(OH)2D3 on the pyroptosis of T2DM pancreatic cells. Different concentrations(5×10-6,5×10-7,5×10-8,5×10-9 mmol/L) of 1,25(OH)2D3 interfered with Min6 cells for 24 hours and the cell viability was detected. Before and after GSDMD siRNA transfection(NC group and siRNA group), Min6 cells were treated with STZ(STZ group and siRNA-STZ group) to establish diabetic cell models, and then 1,25(OH)2D3 was used to intervene in each experimental group(NC-VD group, STZ-VD group, siRNA-VD group, siRNA-STZ-VD group). ELISA kit was used to detect the secretion of insulin from cell supernatant in each group; Lactate dehydrogenase kit was used to detect the release of LDH in the cell supernatant of each group; ELISA kit was used to detect the release of inflammatory factors IL-18 and IL-1β in the cell supernatant of each group; Western Blot was used to detect the expression of pyroptosis-related proteins(NLRP3, NF-κB, caspase-1, GSDMD). Results: STZ treatment caused cell function damage, and insulin secretion content decreased significantly(p<0.001). The protein expression of NLRP3, NF-κB, caspase-1 and GSDMD were upregulated(p<0.01),the expression of the inflammatory factors IL-18、IL-1β were upregulated and the release of LDH was upregulated; 1,25(OH)2D3 intervention can reduce cell damage and increase insulin secretion of the damaged cells(p<0.001), downregulated the protein expression of NLRP3, NF-κB, caspase-1, and GSDMD(p<0.001), reduce the release of inflammatory factors IL-18、IL-1β, and LDH(p<0.01). Inhibiting the expression of GSDMD protein can downregulate the expression level of related proteins, hinder the formation of pores in the plasma membrane of the cell, inhibit the occurrence of cell pyrolysis, and reduce the expansion of the inflammatory cascade. Conclusion: STZ can cause pancreatic cell damage and induce pyroptosis, while 1,25(OH)2D3 intervention can alleviate the cell damage caused by STZ and inhibit the occurrence of pyroptosis.

Keywords： 1,25(OH)2D3 Diabetes Pyroptosis Inflammation Min6 cell