The iNOS/Src/FAK axis is critical in Toll-like receptor-mediated cell motility in macrophages.
The Toll-like receptors (TLRs) play a pivotal role in innate immunity for the detection of highly conserved, pathogen-expressed molecules. Previously, we demonstrated that lipopolysaccharide (LPS, TLR4 ligand)-increased macrophage motility required the participation of Src and FAK, which was inducible nitric oxide synthase (iNOS)-dependent. To investigate whether this iNOS/Src/FAK pathway is a general mechanism for macrophages to mobilize in response to engagement of TLRs other than TLR4, peptidoglycan (PGN, TLR2 ligand), polyinosinic-polycytidylic acid (polyI:C, TLR3 ligand) and CpG-oligodeoxynucleotides (CpG, TLR9 ligand) were used to treat macrophages in this study. Like LPS stimulation, simultaneous increase of cell motility and Src (but not Fgr, Hck, and Lyn) was detected in RAW264.7, peritoneal macrophages, and bone marrow-derived macrophages exposed to PGN, polyI:C and CpG. Attenuation of Src suppressed PGN-, polyI:C-, and CpG-elicited movement and the level of FAK Pi-Tyr861, which could be reversed by the reintroduction of siRNA-resistant Src. Besides, knockdown of FAK reduced the mobility of macrophages stimulated with anyone of these TLR ligands. Remarkably, PGN-, polyI:C-, and CpG-induced Src expression, FAK Pi-Tyr861, and cell mobility were inhibited in macrophages devoid of iNOS, indicating the importance of iNOS. These findings corroborate that iNOS/Src/FAK axis occupies a central role in macrophage locomotion in response to engagement of TLRs.
Maa
Ming-Chei
MC
Institute of Molecular Systems Biomedicine, China Medical University, Taichung, Taiwan, Republic of China. mcmaa@mail.cmu.edu.tw
Chang
Miao Ying
MY
Li
Jiarung
J
Li
Yu-Yun
YY
Hsieh
Ming-Yu
MY
Yang
Ching-Jau
CJ
Chen
Yen-Jen
YJ
Li
Yahan
Y
Chen
Hui-Chen
HC
Cheng
Wei Erh
WE
Hsieh
Ching-Yun
CY
Cheng
Chun-Wen
CW
Leu
Tzeng-Horng
TH
D000818:Animals; D015153:Blotting, Western; D002448:Cell Adhesion; D002465:Cell Movement; D002478:Cells, Cultured; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D052247:Nitric Oxide Synthase Type II / Q000502:physiology*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000378:metabolism*; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D008070:Lipopolysaccharides; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051193:Toll-Like Receptors; D052247:Nitric Oxide Synthase Type II; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D019061:src-Family Kinases