ABSTRACT
Objective:To explore the effect of high glucose-based peritoneal dialysis fluids on NLRP3-IL-1β in human peritoneal mesothelial cells.Methods:HMrSV5 cells (SV40 immortalized human peritoneal mesothelial cell line) were grown in type Ⅰ collagen-coated dishes in DMEM/F12 containing 10％ fetal calf serum (FCS).All experiments on HMrSV5 cells were performed between passages 5 and 10.The cells were divided into 7 groups:control,1.5％ dextrose,2.5％ dextrose,4.25％ dextrose,rotenone,thenoyltrifluoroacetone (TTFA),and antimycin A.Immunoblotting was used to evaluate the expression of IL-1 β.Small interfering RNA (siRNA) targeting NLRP3 was used to downregulate the expression of NLRP3 and Western blot was used to evaluate the expression of IL-1 β in human peritoneal mesothelial cells exposed to 4.25％ dextrose.In the meanwhile,resveratrol (RSV) was used to induce autophagy,3-methyladenine (3-MA) and siRNA against Beclin 1 or ATG5 were used to block autophagy,flow cytometric was used to analyze the respiring (mitotracker deep red),total (mitotracker green) and reactive oxygen species (ROS)-generating mitochondria (mitoSOX);Western blot was used to evaluate the expression of IL-1β.Results:The IL-1β relative expressions were 0,0.175 ±0.082,0.418 ± 0.163,2.357 ±0.288,2.642 ±0.358,3.271 ±0.462,and 0.123 ±0.091,indicating that the cells exposed to high glucose-based peritoneal dialysis fluids and cells treated with mitochondria respiratory chain key enzyme complex Ⅰ,and complex Ⅲ inhibitors increased the IL-1β expression.And we found that NLRP3 knock-down significantly blocked the upregulation of IL-1 β.In addition,the fluorescence intensity of total mitochondria and ROS-generating mitochondria in the following groups:control,negative control,RSV,3-MA,ATG5 siRNA,Beclin1 siRNA were 1.76 ± 0.42,1.83 ± 0.55,1.85 ± 0.62,7.36 ± 0.92,5.35 ± 0.77,5.06 ± 0.62 and 821.68 ± 95.12,868.15 ± 102.82,723.39 ± 92.56,1 660.08 ± 113.65,1 433.01 ± 107.24,1 562.36 ± 112.88 respectively.The increased concentrations of mitochondrial ROS and IL-1β upregulation were confirmed in the inhibition but not the induction of autophagy.We also found that downregulation of ATG5 and Beclin1 sensitized cells for the release of IL-1β induced by MSU (monosodium urate) or nigericin which was the NLRP3 inflammasome activator.RSV treatment attentuated this effect.Conclusion:Long-term application of high glucose-based peritoneal dialysis fluids can trigger the consistent activation of NLRP3-IL-1ββ in peritoneal mesothelial cells.Timely initiation of autophagy may block the NLRP3-IL-1ββ activation and provide a basis for the further development of a potential therapeutic strategy for delay of chronic inflammation and peritoneal fibrosis associated with peritoneal dialysis.