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International Journal Of Bilogical Sciences

.: Home > International Journal Of Bilogical Sciences > 2013 > Volume 9 Number 1 > Ao Cheng*, Yuanyuan Dong*, Fengxin Zhu, Youhua Liu, Fan Fan Hou✉, Jing Nie✉

AGE-LDL Activates Toll Like Receptor 4 Pathway and Promotes Inflammatory Cytokines Production in Renal Tubular Epithelial Cells

Ao Cheng*, Yuanyuan Dong*, Fengxin Zhu, Youhua Liu, Fan Fan Hou✉, Jing Nie✉
Division of Nephrology, Nanfang Hospital, Southern Medical University, Research Institute of Nephrology Guangdong Province, Key Lab for Organ Failure Research, Ministry of Education, Guangzhou, P.R. China.
Abstract :

Background/Aims: Accumulation of advanced glycation end-products, the well-recognized pro-inflammatory molecules, has been detected in renal tissues including tubules. The aim of the present study was to investigate the role of advanced glycation end-products modified low density lipoprotein (AGE-LDL) in inflammatory cytokines production in human proximal tubular epithelial cells and the underlying mechanism. Methods: The Interleukin-6 (IL-6) and Interleukin-8 (IL-8) production was examined by real-time PCR and ELISA. The expression of Toll-like receptor 2 and 4 (TLR2/4) was detected by flow cytometry and western blot. The interaction of TLR2/4 with AGE-LDL was examined by co-immunoprecipitation assay. The involvement of MyD88 and the downstream molecules in inflammatory cytokines production was examined by siRNA and pharmacologic inhibitors, respectively. Results: AGE-LDL interacted with TLR2 and TLR4. TLR4 siRNA showed stronger inhibition on AGE-LDL-induced IL-6 and IL-8 production than that of TLR2 siRNA. Silencing MyD88, but not TRIF, inhibited AGE-LDL-induced IL-6 and IL-8 production. AGE-LDL stimulation led to phosphorylation of JNK, p38, Akt and the p65 subunit of nuclear factor-κB (NF-κB). Pharmacologic inhibitor of Akt suppressed AGE-LDL-induced activation of NF-κB, but the inhibitor of JNK, p38 or ERK1/2 had no effect. Blocking MyD88, p38, JNK, Akt or NF-κB attenuated AGE-LDL-triggered IL-6 production. Conclusion: AGE-LDL induced IL-6 and IL-8 production via TLR2/4-MyD88-dependent pathway in tubular epithelial cells. These data suggest that activation of TLRs signaling in tubular epithelial cells by AGE-LDL might be a novel mechanism for the tubulointerstitial inflammation.

Keywords :
AGE-LDL, Toll like receptor, MyD88, NF-κB, IL-6.

Date Deposited : 09 Apr 2015 15:10

Last Modified : 09 Apr 2015 15:10

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Volume 9, Number 1, - 2013 , ISSN 1545-1003

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