title: Activation of cAMP-dependent pathways in human airway smooth muscle cells inhibits TNF-alpha-induced ICAM-1 and VCAM-1 expression and T lymphocyte adhesion.
abstract: Asthma is a disease of airway inflammation and hyper-reactivity associated with lymphocytic infiltration in the bronchial submucosa. We recently demonstrated that human airway smooth muscle (ASM) cells express the cell adhesion molecules ICAM-1 and VCAM-1, which are up-regulated by cytokines such as TNF-alpha, and which mediate binding of activated T lymphocytes. In this study, we examined whether an increase in [cAMP]i, presumably via activation of cAMP-dependent protein kinase, modulates TNF-alpha-induced ICAM-1 and VCAM-1 on ASM. We found that treatment of ASM with either forskolin, which directly activates adenylyl cyclase, or with cholera toxin, which activates the heterotrimeric GTP-binding protein, Gs, inhibited TNF-alpha-induced cell adhesion molecule expression. In addition, treatment with either isoproterenol or prostaglandin E2, which activates receptors coupled to Gs and increases [cAMP]i, also inhibited TNF-alpha-induced expression of ICAM-1 and VCAM-1 on ASM. Furthermore, adhesion of activated T cells to TNF-alpha-stimulated ASM was inhibited by treating the ASM cells with either forskolin or PGE2. These data suggest that cAMP-dependent protein kinase activation decreases cytokine-induced expression of cell adhesion molecules on ASM cells, modulates T cell binding to airway myocytes and, thus, suggests novel therapeutic approaches to airway inflammation.
authors.affiliation: Department of Medicine, University of Pennsylvania Medical Center, Philadelphia.
authors.forename: R A
authors.initials: RA
authors.lastname: Panettieri
authors.forename: A L
authors.initials: AL
authors.lastname: Lazaar
authors.forename: E
authors.initials: E
authors.lastname: Puré
authors.forename: S M
authors.initials: SM
authors.lastname: Albelda
mesh_terms: D001249:Asthma / Q000276:immunology / Q000378:metabolism; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000096:biosynthesis; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007545:Isoproterenol / Q000494:pharmacology; D008213:Lymphocyte Activation; D009130:Muscle, Smooth / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D014132:Trachea / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D015815:Cell Adhesion Molecules; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D005576:Colforsin; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D015232:Dinoprostone; D007545:Isoproterenol