Advanced Glycation End Products Promote Tnf-а Expression In T Lymphocyte Via P38,jnk And Nf-κb Signal Pathway

Objective: Advanced glycation end products(AGEs) have been implicated in the accelerated atherosclerosis occuring in diabetes.Previous studies showed that AGEs are involved in a vicious cycle of inflammation in endothelial cells,monocytes,macrophages, and then promoting atherosclerosis.Lymphocyte activation and secretion of adhesion cytokine play important roles in the pathogenesis of atherosclerosis.In this study,we examined the effect of AGEs on the expression of TNF-аin Jurkat cells.In addition,the role of the signaling proteins.p38MAPK,NKand NF-κB involved in this regulation will also be investigated.These studies will shed new light on the pathogenesis of diabetes associated accelerated atherosclerosis.Methods: Jurkat cells which prestimulated by phytohemagg lutinin(PHA) were incubated in presence or absence of AGEs or BSA for 24h.The cells viability was detected by MTT.After 24h incubation,the medium was collected and the release of TNF-аwas tested by ELISA.Total and phosphorylated p38,JNK and Akt in extracts were assessed using western-blot after treatment of AGEs for 0~40min.To further explore the relationship between AGEs and inflammatory response,various pharmacological agents were supplemented to the incubation medium including p38 inhibitors SB203580(25μM),JNK inhibitors SP600125(25μM) and antioxidants N-acetyl-L-cysteine(100μg/ml).Total and phosphorylated IκB were assessed using western-blot after treatment of these pharmacological agents after 30min.After 24h incubation with various pharmacological agents,the medium were collected and the release of TNF-аwas tested by ELISA.Results:No changes in cells viability was observed when Jurkat cells were treated with 100~400μg/ml AGEs and unmodified BSA for 24h.The release of TNF-аfrom Jurkat cells was significantly increased by all concentrations of AGEs.Non-glycated BSA,used as a control,had no significant effect on TNF-аexpression from Jurkat cells.In cubation of Jurkat cells with 200μg/ml AGEs results in significant increase in p38,JNK phosphorylation but not Akt.Furthermore,IκB phosphorylation and TNF-аexpression were significantly suppressed in the presence of the specific inhibitors SB203580(25μM) and SP600125(25μM) respectively.In addition,by arresting activation of other signal pathways,we demonstrated that antioxidant NAC significantly suppressed the IκB phosphorylation and TNF-аexpression in Jurkat cells.Conclusion: The findings from this study suggest that AGEs mediates inflammatory actions in T lymphocytes via p38,JNK,NF-κB signal pathway.Oxidative stress may be another important pathway in Jurkat cells induced by AGEs.