title: Caveolin-1 and force regulation in porcine airway smooth muscle.
abstract: Caveolae are specialized membrane microdomains expressing the scaffolding protein caveolin-1. We recently demonstrated the presence of caveolae in human airway smooth muscle (ASM) and the contribution of caveolin-1 to intracellular calcium ([Ca(2+)](i)) regulation. In the present study, we tested the hypothesis that caveolin-1 regulates ASM contractility. We examined the role of caveolins in force regulation of porcine ASM under control conditions as well as TNF-α-induced airway inflammation. In porcine ASM strips, exposure to 10 mM methyl-β-cyclodextrin (CD) or 5 μM of the caveolin-1 specific scaffolding domain inhibitor peptide (CSD) resulted in time-dependent decrease in force responses to 1 μM ACh. Overnight exposure to the cytokine TNF-α (50 ng/ml) accelerated and increased caveolin-1 expression and enhanced force responses to ACh. Suppression of caveolin-1 with small interfering RNA mimicked the effects of CD or CSD. Regarding mechanisms by which caveolae contribute to contractile changes, inhibition of MAP kinase with 10 μM PD98059 did not alter control or TNF-α-induced increases in force responses to ACh. However, inhibiting RhoA with 100 μM fasudil or 10 μM Y27632 resulted in significant decreases in force responses, with lesser effects in TNF-α exposed samples. Furthermore, Ca(2+) sensitivity for force generation was substantially reduced by fasudil or Y27632, an effect even more enhanced in the absence of caveolin-1 signaling. Overall, these results indicate that caveolin-1 is a critical player in enhanced ASM contractility with airway inflammation.
authors.affiliation: Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
authors.forename: Venkatachalem
authors.initials: V
authors.lastname: Sathish
authors.forename: Binxia
authors.initials: B
authors.lastname: Yang
authors.forename: Lucas W
authors.initials: LW
authors.lastname: Meuchel
authors.forename: Sarah K
authors.initials: SK
authors.lastname: VanOosten
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Ryu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Thompson
authors.forename: Y S
authors.initials: YS
authors.lastname: Prakash
authors.forename: Christina M
authors.initials: CM
authors.lastname: Pabelick
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism; D051242:Caveolin 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D012137:Respiratory System / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology; D047392:beta-Cyclodextrins / Q000494:pharmacology*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D051242:Caveolin 1; D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D014665:Vasodilator Agents; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D020928:Mitogen-Activated Protein Kinases; D020742:rhoA GTP-Binding Protein; D000109:Acetylcholine; D002118:Calcium