title: Calcineurin-mediated pathway involved in the differentiated phenotype of smooth muscle cells.
abstract: The calcineurin-mediated pathway is involved in skeletal and cardiac hypertrophy and vascular development in vivo, but the relationship between this pathway and the phenotype of smooth muscle cells (SMCs) remains unknown. Using visceral SMCs in culture as a model system of differentiated SMCs, we investigated the role of the calcineurin-mediated pathway in maintaining the differentiated phenotype of SMCs, which depends on the insulin-like growth factor (IGF-I)-triggered activation of the phosphatidylinositol 3-kinase (PI3-K)/protein kinase B (PKB(Akt)) pathway. Treatment with calcineurin inhibitors, cyclosporin A or FK506, or the forced expression of the natural calcineurin inhibitor, CAIN, induced SMC dedifferentiation. Notably, suppression of the promoter activities of the SMC molecular markers caldesmon and alpha1 integrin by blocking the PI3-K/PKB(Akt) pathway was rescued by the forced expression of constitutively active calcineurin Aalpha, suggesting that the calcineurin-mediated pathway is critical for maintaining the differentiated phenotype of SMCs and works downstream of the PI3-K/PKB(Akt) pathway.
authors.affiliation: Department of Neuroscience, Osaka University Graduate School of Medicine (D13), 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ohkawa
authors.forename: Ken'ichiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Sobue
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000378:metabolism*; D065095:Calcineurin Inhibitors; D002148:Calmodulin-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D002642:Chick Embryo; D016572:Cyclosporine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D039423:Integrin alpha1 / Q000235:genetics / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010641:Phenotype; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000502:physiology*; D016559:Tacrolimus / Q000494:pharmacology
chemical_list: D019703:Calcineurin; D065095:Calcineurin Inhibitors; D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D016572:Cyclosporine; D004791:Enzyme Inhibitors; D007334:Insulin-Like Growth Factor I; D039423:Integrin alpha1; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D016559:Tacrolimus