title: Role of dystrophin in airway smooth muscle phenotype, contraction and lung function.
abstract: Dystrophin links the transmembrane dystrophin-glycoprotein complex to the actin cytoskeleton. We have shown that dystrophin-glycoprotein complex subunits are markers for airway smooth muscle phenotype maturation and together with caveolin-1, play an important role in calcium homeostasis. We tested if dystrophin affects phenotype maturation, tracheal contraction and lung physiology. We used dystrophin deficient Golden Retriever dogs (GRMD) and mdx mice vs healthy control animals in our approach. We found significant reduction of contractile protein markers: smooth muscle myosin heavy chain (smMHC) and calponin and reduced Ca2+ response to contractile agonist in dystrophin deficient cells. Immunocytochemistry revealed reduced stress fibers and number of smMHC positive cells in dystrophin-deficient cells, when compared to control. Immunoblot analysis of Akt1, GSK3β and mTOR phosphorylation further revealed that downstream PI3K signaling, which is essential for phenotype maturation, was suppressed in dystrophin deficient cell cultures. Tracheal rings from mdx mice showed significant reduction in the isometric contraction to methacholine (MCh) when compared to genetic control BL10ScSnJ mice (wild-type). In vivo lung function studies using a small animal ventilator revealed a significant reduction in peak airway resistance induced by maximum concentrations of inhaled MCh in mdx mice, while there was no change in other lung function parameters. These data show that the lack of dystrophin is associated with a concomitant suppression of ASM cell phenotype maturation in vitro, ASM contraction ex vivo and lung function in vivo, indicating that a linkage between the DGC and the actin cytoskeleton via dystrophin is a determinant of the phenotype and functional properties of ASM.
authors: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; CIHR National Training Program in Allergy and Asthma, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors: Pawan
authors: P
authors: Sharma
authors: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors: Sujata
authors: S
authors: Basu
authors: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors: Richard W
authors: RW
authors: Mitchell
authors: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors: Gerald L
authors: GL
authors: Stelmack
authors: Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
authors: Judy E
authors: JE
authors: Anderson
authors: Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada; Section of Respiratory Disease, University of Manitoba, Winnipeg, Manitoba, Canada; CIHR National Training Program in Allergy and Asthma, University of Manitoba, Winnipeg, Manitoba, Canada; Biology of Breathing Group, Manitoba Institute of Child Health, Winnipeg, Manitoba, Canada.
authors: Andrew J
authors: AJ
authors: Halayko
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004285:Dogs; D016189:Dystrophin / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D016210:Methacholine Chloride / Q000494:pharmacology; D018101:Mice, Inbred mdx; D018345:Mice, Knockout; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D009119:Muscle Contraction / Q000235:genetics / Q000502:physiology*; D009130:Muscle, Smooth / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D018995:Myosin Heavy Chains / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D012137:Respiratory System / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014132:Trachea / Q000187:drug effects / Q000378:metabolism / Q000502:physiology
chemical_list: D016189:Dystrophin; D016210:Methacholine Chloride; D019869:Phosphatidylinositol 3-Kinases; D018995:Myosin Heavy Chains