Role of UBC9-mediated SUMO modification in homocysteine-induced pyroptosis of macrophages
Objective To study the role of ubiquitin-conjugating enzyme 9(UBC9)in the pyroptosis of homocysteine-induced macrophages mediated by small ubiquitin-like modifier(SUMO)modification.Methods First,the effects of homocysteine at different concentrations(0 μmol/L,50 μ.mol/L,100 μmol/L,150 µmol/L and 200 μmol/L)on the viability and pyrodeath of mouse macrophages(RAW264.7)were detected by CCK-8 and Western blot.Western blot was used to detect the expression levels of UBC9,SUMO-1,and the inflammatory cytokine IL-1β in different groups of cells.qRT-PCR was used to detect the mRNA expression of UBC9 before and after RNA interference and the expression of UBC9,pyrogen-related protein,and SUMO-1 after RNA interference.Results After stimulation with 100 µmol/L homocysteine,the effect of macrophage activity was minimal,and NLRP3 and Caspase-1 were the proteins with the most obvious increase in expression(P<0.05).Compared with the Control group,the Hcy group's expression of IL-1β and SUMO-1 was increased(P<0.01).Compared with the Control group,the Hcy group's UBC9 protein and mRNA levels were increased(P<0.05).The expression of NLRP3,Caspase-1,IL-1β,UBC9,and SUMO-1 was decreased in the si-UBC9+Hcy group compared with the si-NC+Hcy group(P<0.01).Conclusions Homocysteine induces pyroptosis in macrophages,and its mechanism of action is related to the up-regulation of UBC9 to induce SUMO modification.