Caveolin-1 Tyr14 phosphorylation induces interaction with TLR4 in endothelial cells and mediates MyD88-dependent signaling and sepsis-induced lung inflammation.
Activation of TLR4 by the endotoxin LPS is a critical event in the pathogenesis of Gram-negative sepsis. Caveolin-1, the signaling protein associated with caveolae, is implicated in regulating the lung inflammatory response to LPS; however, the mechanism is not understood. In this study, we investigated the role of caveolin-1 in regulating TLR4 signaling in endothelial cells. We observed that LPS interaction with CD14 in endothelial cells induced Src-dependent caveolin-1 phosphorylation at Tyr(14). Using a TLR4-MD2-CD14-transfected HEK-293 cell line and caveolin-1-deficient (cav-1(-/-)) mouse lung microvascular endothelial cells, we demonstrated that caveolin-1 phosphorylation at Tyr(14) following LPS exposure induced caveolin-1 and TLR4 interaction and, thereby, TLR4 activation of MyD88, leading to NF-κB activation and generation of proinflammatory cytokines. Exogenous expression of phosphorylation-deficient Y14F caveolin-1 mutant in cav-1(-/-) mouse pulmonary vasculature rendered the mice resistant to LPS compared with reintroduction of wild-type caveolin-1. Thus, caveolin-1 Y14 phosphorylation was required for the interaction with TLR4 and activation of TLR4-MyD88 signaling and sepsis-induced lung inflammation. Inhibiting caveolin-1 Tyr(14) phosphorylation and resultant inactivation of TLR4 signaling in pulmonary vascular endothelial cells represent a novel strategy for preventing sepsis-induced lung inflammation and injury.
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.|Department of Anesthesiology, Xuzhou Medical College, Xuzhou, China.
Hao
H
Jiao
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.|Department of Anesthesiology, Xuzhou Medical College, Xuzhou, China.
Yang
Y
Zhang
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.
Zhibo
Z
Yan
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.
Zhen-Guo
ZG
Wang
Department of Anesthesiology, Xuzhou Medical College, Xuzhou, China.
Gongjian
G
Liu
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.|Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL.
Richard D
RD
Minshall
Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL.
Asrar B
AB
Malik
Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL.|Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL.
Guochang
G
Hu
D019943:Amino Acid Substitution; D000818:Animals; D051242:Caveolin 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology; D019446:Endotoxemia / Q000473:pathology; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation; D053592:Interleukin-1 Receptor-Associated Kinases / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D008070:Lipopolysaccharides / Q000633:toxicity; D008168:Lung / Q000098:blood supply / Q000473:pathology; D051379:Mice; D055806:Microvessels / Q000166:cytology; D020125:Mutation, Missense; D053594:Myeloid Differentiation Factor 88 / Q000502:physiology; D000072000:NF-KappaB Inhibitor alpha; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000096:biosynthesis / Q000502:physiology*; D017354:Point Mutation; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000502:physiology*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D019061:src-Family Kinases / Q000378:metabolism
D051242:Caveolin 1; D020672:I-kappa B Proteins; D015850:Interleukin-6; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D011993:Recombinant Fusion Proteins; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D019000:Phosphotyrosine; D019061:src-Family Kinases; D053592:Interleukin-1 Receptor-Associated Kinases; C507769:Irak1 protein, mouse