Focal adhesion kinase (FAK) and mechanical stimulation negatively regulate the transition of airway smooth muscle tissues to a synthetic phenotype.
The effects of mechanical forces and focal adhesion kinase (FAK) in regulating the inflammatory responses of airway smooth muscle (ASM) tissues to stimulation with interleukin (IL)-13 were investigated. Canine tracheal tissues were subjected to different mechanical loads in vitro, and the effects of mechanical load on eotaxin secretion and inflammatory signaling pathways in response to IL-13 were determined. Eotaxin secretion by tissues in response to IL-13 was significantly inhibited in muscles maintained at a higher (+) load compared with those at a lower (-) load as assessed by ELISA, and Akt activation was also reduced in the higher (+) loaded tissues. Conversely the (+) mechanical load increased activation of the focal adhesion proteins FAK and paxillin in the tissues. The role of FAK in regulating the mechanosensitive responses was assessed by overexpressing FAK-related nonkinase in the tissues, by expressing the FAK kinase-dead mutant FAK Y397F, or by treating tissues with the FAK inhibitor PF-573228. FAK inactivation potentiated Akt activity and increased eotaxin secretion in response to IL-13. FAK inhibition also suppressed the mechanosensitivity of Akt activation and eotaxin secretion. In addition, FAK inactivation suppressed smooth muscle myosin heavy chain expression induced by the higher (+) mechanical load. The results demonstrate that the imposition of a higher mechanical load on airway smooth muscle stimulates FAK activation, which promotes the expression of the differentiated contractile phenotype and suppresses the synthetic phenotype and the inflammatory responses of the muscle tissue.
Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.
Yidi
Y
Wu
Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.
Youliang
Y
Huang
Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana sgunst@iupui.edu.
Susan J
SJ
Gunst
D000818:Animals; D054413:Chemokine CCL11 / Q000378:metabolism; D004285:Dogs; D004789:Enzyme Activation / Q000187:drug effects; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D018793:Interleukin-13 / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D018995:Myosin Heavy Chains / Q000378:metabolism; D051419:Paxillin / Q000378:metabolism; D010641:Phenotype; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015363:Quinolones / Q000494:pharmacology; D013314:Stress, Mechanical; D013450:Sulfones / Q000494:pharmacology; D014132:Trachea / Q000473:pathology
C521108:6-(4-(3-(methylsulfonyl)benzylamino)-5-(trifluoromethyl)pyrimidin-2-ylamino)-3,4-dihydroquinolin-2(1H)-one; D054413:Chemokine CCL11; D018793:Interleukin-13; D051419:Paxillin; D015363:Quinolones; D013450:Sulfones; D049452:Green Fluorescent Proteins; C113183:FAK-related nonkinase; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051057:Proto-Oncogene Proteins c-akt; D018995:Myosin Heavy Chains
FAK-related nonkinase; PKB/Akt; adhesion complex; eotaxin; mechanotransduction