title: Insulin increases the expression of contractile phenotypic markers in airway smooth muscle.
abstract: We have previously demonstrated that long-term exposure of bovine tracheal smooth muscle (BTSM) strips to insulin induces a functional hypercontractile phenotype. To elucidate molecular mechanisms by which insulin might induce maturation of contractile phenotype airway smooth muscle (ASM) cells, we investigated effects of insulin stimulation in serum-free primary BTSM cell cultures on protein accumulation of specific contractile phenotypic markers and on the abundance and stability of mRNA encoding these markers. In addition, we used microscopy to assess insulin effects on ASM cell morphology, phenotype, and induction of phosphatidylinositol (PI) 3-kinase signaling. It was demonstrated that protein and mRNA levels of smooth muscle-specific contractile phenotypic markers, including sm-myosin, are significantly increased after stimulation of cultured BTSM cells with insulin (1 microM) for 8 days compared with cells treated with serum-free media, whereas mRNA stability was unaffected. In addition, insulin treatment promoted the formation of large, elongate ASM cells, characterized by dramatic accumulation of contractile phenotype marker proteins and phosphorylated p70(S6K) (downstream target of PI 3-kinase associated with ASM maturation). Insulin effects on protein accumulation and cell morphology were abrogated by combined pretreatment with the Rho kinase inhibitor Y-27632 (1 microM) or the PI 3-kinase inhibitor LY-294002 (10 microM), indicating that insulin increases the expression of contractile phenotypic markers in BTSM in a Rho kinase- and PI 3-kinase-dependent fashion. In conclusion, insulin increases transcription and protein expression of contractile phenotypic markers in ASM. This could have important implications for the use of recently approved aerosolized insulin formulations in diabetes mellitus.
authors: Dept. of Molecular Pharmacology, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands. d.schaafsma@rug.nl
authors: Dedmer
authors: D
authors: Schaafsma
authors: Karol D
authors: KD
authors: McNeill
authors: Gerald L
authors: GL
authors: Stelmack
authors: Reinoud
authors: R
authors: Gosens
authors: Hoeke A
authors: HA
authors: Baarsma
authors: Bart G J
authors: BG
authors: Dekkers
authors: Erin
authors: E
authors: Frohwerk
authors: Jelte-Maarten
authors: JM
authors: Penninks
authors: Pawan
authors: P
authors: Sharma
authors: Karen M
authors: KM
authors: Ens
authors: S Adriaan
authors: SA
authors: Nelemans
authors: Johan
authors: J
authors: Zaagsma
authors: Andrew J
authors: AJ
authors: Halayko
authors: Herman
authors: H
authors: Meurs
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002417:Cattle; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D003285:Contractile Proteins / Q000235:genetics / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000378:metabolism / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects* / Q000235:genetics; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D009924:Organ Culture Techniques; D010641:Phenotype; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D014176:Protein Biosynthesis / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D017527:Receptor, IGF Type 2 / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D024745:Smooth Muscle Myosins / Q000378:metabolism; D013997:Time Factors; D014132:Trachea / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D054460:rho-Associated Kinases; D000096985:Calponins
chemical_list: D000577:Amides; D002135:Calcium-Binding Proteins; D002867:Chromones; D003285:Contractile Proteins; D007004:Hypoglycemic Agents; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D008840:Microfilament Proteins; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines; D012333:RNA, Messenger; D017526:Receptor, IGF Type 1; D017527:Receptor, IGF Type 2; D011972:Receptor, Insulin; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D024745:Smooth Muscle Myosins; D054460:rho-Associated Kinases; D000096985:Calponins; C108830:Y 27632; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one