title: Nox2/ROS-dependent human antigen R translocation contributes to TNF-α-induced SOCS-3 expression in human tracheal smooth muscle cells.
abstract: Elevated levels of TNF-α have been detected in the airway fluids, which may induce upregulation of inflammatory proteins. Suppressors of cytokine signaling (SOCS)-3 proteins can be induced by various cytokines and negatively regulated inflammatory responses. Although TNF-α has been shown to induce SOCS-3 expression, the mechanisms underlying TNF-α-induced SOCS-3 expression in human tracheal smooth muscle cells (HTSMCs) remain unclear. Here, we showed that TNF-α induced SOCS-3 expression, which was inhibited by pretreatment with the inhibitor of transcription level (actinomycin D), translation level (cycloheximide), JNK1/2 (SP600125), MEK1/2 (U0126), NADPH oxidase (Nox; apocynin and diphenyleneiodonium chloride), or reactive oxygen species (ROS; N-acetyl-l-cysteine) and transfection with siRNA of JNK1, p47(phox), p42, Nox2, or human antigen R (HuR). In addition, TNF-α-stimulated JNK1/2 and p42/p44 MAPK phosphorylation, Nox activation, and ROS generation were inhibited by pretreatment with U0126 or SP600125 and transfection with siRNA of JNK1 or p42. We further showed that TNF-α markedly induced HuR protein expression and translocation from the nucleus to the cytosol, which could stabilize SOCS-3 mRNA. Moreover, TNF-α-enhanced HuR translocation was reduced by transfection with siRNA of p42, JNK1, or p47(phox). These results suggested that TNF-α induces SOCS-3 protein expression and mRNA stabilization via a TNFR1/JNK1/2, p42/p44 MAPK/Nox2/ROS-dependent HuR signaling in HTSMCs. Lipopolysaccharide (LPS) has been shown to play a key role in inflammation via induction of adhesion molecules and then causes airway and lung injury. Moreover, we also demonstrated that overexpression of SOCS-3 protects against LPS-induced adhesion molecules expression and airway inflammation.
authors.affiliation: Dept. of Pharmacology, Chang Gung Univ., 259 Wen-Hwa 1st Rd., Kwei-San, Tao-Yuan, Taiwan. chuenmao@mail.cgu.edu.tw.
authors.forename: Chih-Kai
authors.initials: CK
authors.lastname: Hsu
authors.forename: I-Ta
authors.initials: IT
authors.lastname: Lee
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Li-Der
authors.initials: LD
authors.lastname: Hsiao
authors.forename: Chuen-Mao
authors.initials: CM
authors.lastname: Yang
mesh_terms: D000818:Animals; D001249:Asthma / Q000276:immunology / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000378:metabolism; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000378:metabolism*; D014132:Trachea / Q000166:cytology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D047888:Receptors, Tumor Necrosis Factor, Type I; C106644:SOCS3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D003513:Cycloheximide; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases
keywords: MAPKs; NADPH oxidase; airway inflammation; human antigen R; suppressors of cytokine signaling