Inhibition of Extracellular Calcium Influx Results in Enhanced IL-12 Production in LPS-Treated Murine Macrophages by Downregulation of the CaMKKβ-AMPK-SIRT1 Signaling Pathway.
Activated macrophages are the primary sources of IL-12, a key cytokine bridging innate and adaptive immunity. However, macrophages produce low amounts of IL-12 upon stimulation and the underlying regulatory mechanism remains unclear. In this study, we found a new calcium-dependent mechanism that controlled IL-12 production in LPS-treated murine macrophages. First, LPS was demonstrated to induce extracellular calcium entry in murine peritoneal macrophages and inhibition of calcium influx resulted in marked enhancement in IL-12 production. Then, withdrawal of extracellular calcium was found to suppress CaMKKβ and AMPK activation triggered by LPS while chemical inhibition or genetic knockdown of these two kinases augmented LPS induced IL-12 production. AMPK activation increased the NAD(+)/NADH ratio and activated Sirtuin 1 (SIRT1), a NAD(+)-dependent deacetylating enzyme and negative regulator of inflammation. Chemical inhibitor or siRNA of SIRT1 enhanced IL-12 release while its agonist suppressed IL-12 production. Finally, it was found that SIRT1 selectively affected the transcriptional activity of NF-κB which thereby inhibited IL-12 production. Overall, our study demonstrates a new role of transmembrane calcium mobilization in immunity modulation such that inhibition of calcium influx leads to impaired activation of CaMKKβ-AMPK-SIRT1 signaling pathway which lifts restriction on NF-κB activation and results in enhanced IL-12 production.
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Xin
0000-0002-2986-6364
X
Liu
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Ning
0000-0002-9913-5006
N
Wang
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Yuanfeng
Y
Zhu
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Yongjun
Y
Yang
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Xiaoli
X
Chen
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Shijun
S
Fan
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Qian
Q
Chen
Department of Pharmacology, College of Pharmacy, The Third Military Medical University, Chongqing 400038, China.
Hong
0000-0002-6336-5854
H
Zhou
Medical Research Center, Southwest Hospital, The Third Military Medical University, Chongqing 400038, China.
Jiang
J
Zheng
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D008780:Methyltransferases / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D056564:Sirtuin 1 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D018664:Interleukin-12; D008780:Methyltransferases; C038999:calmodulin-lysine methyltransferase; D055372:AMP-Activated Protein Kinases; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1; D002118:Calcium