Requirement for both JAK-mediated PI3K signaling and ACT1/TRAF6/TAK1-dependent NF-kappaB activation by IL-17A in enhancing cytokine expression in human airway epithelial cells.
Through DNA microarray analysis and quantitative PCR verification, we have identified additional IL-17A-inducible genes-IL-19, CXCL-1, -2, -3, -5, and -6-in well-differentiated normal human bronchial epithelial cells. These genes, similar to previously described human beta-defensin-2 (HBD-2) and CCL-20, were induced by a basolateral treatment of IL-17A, and regulated by PI3K signaling and NF-kappaB activation. For PI3K signaling, increases of cellular PIP(3) and phosphorylation of downstream molecules, such as Akt and glycogen synthase kinase-3beta (GSK3beta) (S9), were detected. Induced gene expression and HBD-2 promoter activity were attenuated by LY294002, p110alpha small-interfering RNA (siRNA), as well as by an overexpression of constitutively active GSK3beta(S9A) or wild-type phosphatase and tensin homolog. Increased phosphorylation of JAK1/2 after IL-17A treatment was detected in primary normal human bronchial epithelium cells. Transfected siRNAs of JAK molecules and JAK inhibitor I decreased IL-17A-induced gene expression and GSK3beta(S9) phosphorylation. However, both JAK inhibitor I and PI3K inhibitor had no effect on the DNA-binding activities of p65 and p50 to NF-kappaB consensus sequences. This result suggested a JAK-associated PI3K signaling axis is independent from NF-kappaB activation. With siRNA to knockdown STIR (similar expression to fibroblast growth factor and IL-17R; Toll-IL-1R)-related signaling molecules, such as Act1, TNFR-associated factor 6 (TRAF6), and TGF-beta-activated kinase 1 (TAK1), and transfection of A52R, an inhibitor of the MyD88/TRAF6 complex, or dominant-negative TAK1, IL-17A-inducible gene expression and HBD-2 promoter activity were reduced. Additionally, IL-17A-induced p65 and p50 NF-kappaB activations were confirmed and their nuclear translocations were down-regulated by siRNAs of TRAF6 and TAK1. These results suggest that two independent and indispensable signaling pathways-1) JAK1-associated PI3K signaling and 2) Act1/TRAF6/TAK1-mediated NF-kappaB activation-are stimulated by IL-17A to regulate gene induction in human airway epithelial cells.
Huang
Fei
F
Center for Comparative Respiratory Biology and Medicine, University of California, Davis, CA 95616, USA.
Kao
Cheng-Yuan
CY
Wachi
Shinichiro
S
Thai
Philip
P
Ryu
Jisu
J
Wu
Reen
R
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D048868:Adaptor Proteins, Signal Transducing; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism / Q000494:pharmacology*; D053613:Janus Kinase 1 / Q000235:genetics / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D052002:NF-kappa B p50 Subunit / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D020218:Response Elements / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D035381:TATA-Binding Protein Associated Factors / Q000235:genetics / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D023083:beta-Defensins / Q000096:biosynthesis / Q000235:genetics; D000099151:MAP Kinase Kinase Kinase 7
D048868:Adaptor Proteins, Signal Transducing; D002867:Chromones; D016207:Cytokines; D004791:Enzyme Inhibitors; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D007295:Inositol Phosphates; D020381:Interleukin-17; D053613:Janus Kinase 1; D020930:MAP Kinase Kinase Kinases; D009025:Morpholines; D053594:Myeloid Differentiation Factor 88; D052002:NF-kappa B p50 Subunit; D019869:Phosphatidylinositol 3-Kinases; D034741:RNA, Small Interfering; D035381:TATA-Binding Protein Associated Factors; D051996:Transcription Factor RelA; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D023083:beta-Defensins; D000099151:MAP Kinase Kinase Kinase 7; C106641:DEFB4A protein, human; C508717:IL17A protein, human; C507779:MYD88 protein, human; C084977:TAF6 protein, human; C414202:TRAF3IP2 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C507904:JAK1 protein, human; C000605506:GSK3B protein, human