Influence of albumin on expression of NLRP3 inflammasome in renal tubular epithelial cells / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effect of albumin on expression of NLRP3 inflammasome and its downstream cytokines IL-1β and IL-18 in tubular epithelial cells.Methods Thirty mesangioproliferative glomerulonephritis (MsPGN) patients with different levels of proteinuria were selected, and their renal biopsy samples were stained by PAS and Masson to observe tubular epithelial cells injury and inflammatory cells infiltration.NLRP3, caspase-1, IL-1β and IL-18, as well as different inflammatory cells, were detected by immunohistostaining.In vitro, Western blotting and real-time PCR were employed to detect NLRP3, caspase-1, IL-1β and IL-18 protein and mRNA in HK-2 cells stimulated by bovine serum albumin (BSA) (20 g/L).Results In MsPGN patients with high levels of proteinuria, there were obvious renal tubular epithelial cell injury and inflammatory cells infiltration (all P ＜ 0.05), and the expressions of NLRP3, caspase-1, IL-1β and IL-18 were up-regulated compared to patients with low levels of proteinuria (all P ＜ 0.05).Furthermore, IL-1β and IL-18expressions were positively correlated with the degree of proteinuria (r=0.836, P ＜ 0.05;r=0.901, P ＜0.05).NLRP3, caspase-1, IL-1β and IL-18 protein and mRNA were significantly increased in HK-2cells stimulated by BSA compared to the control group (all P ＜ 0.05).Conclusions Albumin is able to induce NLRP3 inflammasome activation in tubular epithelial cells, which may be the mechanism of tubulointerstitial injury and inflammation caused by proteinuria.