HMGB1 translocation and release mediate cigarette smoke-induced pulmonary inflammation in mice through a TLR4/MyD88-dependent signaling pathway.
We performed studies to determine the role of high-mobility group box 1 (HMGB1) in cigarette smoke (CS)-induced pulmonary inflammation. After mice were exposed to five cigarettes four times a day for 3 d, toll-like receptor 4 (TLR4) expression and TLR4-mediated signaling were significantly up-regulated, and HMGB1 had translocated from the nucleus to the cytoplasm in lung epithelial cells and then been released into the extracellular lung space. On CS exposure, inflammatory cell recruitment and proinflammatory cytokine production were significantly increased in lung tissue and bronchoalveolar lavage, and these effects depended on the TLR4 signaling pathway. HMGB1 inhibition decreased the CS-induced inflammatory response, whereas treatment with exogenous HMGB1 aggravated the damage and increased the phosphorylation of JNK, p38, and IκBα in the lungs of wild-type mice but not in TLR4-knockout mice. Blockade of TLR4 action or TLR4 knockout significantly inhibited HMGB1-induced proinflammatory cytokine production in mouse tracheal epithelial (MTE) cells and lung tissues. In addition, a MyD88 deficiency inhibited JNK, p38, and IκBα phosphorylation, and this effect was associated with the suppressed production of TNF-α and IL-1β in MTE cells and lung tissues in response to CS stimulation. Thus HMGB1 activates the NF-κB and JNK/p38 pathways through TLR4/MyD88-dependent signaling and induces an inflammatory response in lungs exposed to CS.
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.|Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chong-qing 400016, China.
Yao
Y
Cheng
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.|Department of Respiration Medicine, Sichuan University, Chengdu, Sichuan 610041, China.
Dan
D
Wang
Institute of Life Science, Chongqing Medical University, Chong-qing 400016, China.
Bin
B
Wang
College of Biomedical Engineering, Chongqing Medical University, Chong-qing 400016, China.
Huanan
H
Li
Department of General Surgery, Sichuan University, Chengdu, Sichuan 610041, China.
Junjie
J
Xiong
Department of Emergency Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.
Shuyun
S
Xu
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.
Quan
Q
Chen
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.
Kun
K
Tao
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.
Xiaoyan
X
Yang
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China.
Yu
Y
Zhu
Department of Immunology, College of Basic Medicine, Chongqing Medical University, Chong-qing 400016, China hesirong@cqmu.edu.cn.
Sirong
S
He
D000818:Animals; D016207:Cytokines / Q000378:metabolism; D024243:HMGB1 Protein / Q000378:metabolism*; D053583:Interleukin-1beta / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011014:Pneumonia / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D012907:Smoking / Q000378:metabolism / Q000473:pathology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016207:Cytokines; D024243:HMGB1 Protein; C582808:HMGB1 protein, mouse; D053583:Interleukin-1beta; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha