title: Insulin induces production of new elastin in cultures of human aortic smooth muscle cells.
abstract: Diabetes mellitus accelerates atherosclerotic progression, peripheral angiopathy development, and arterial hypertension, all of which are associated with elastic fiber disease. However, the potential mechanistic links between insulin deficiency and impaired elastogenesis in diabetes have not been explored. Results of the present study reveal that insulin administered in therapeutically relevant concentrations (0.5 to 10 nmol/L) selectively stimulates formation of new elastic fibers in cultures of human aortic smooth muscle cells. These concentrations of insulin neither up-regulate collagen type I and fibronectin deposition nor stimulate cellular proliferation. Further, the elastogenic effect of insulin occurs after insulin receptor activation, which triggers the PI3K downstream signaling pathway and activates elastin gene transcription. In addition, the promoter region of the human elastin gene contains the CAAATAA sequence, consistent with the FoxO-recognized element, and the genomic effects of insulin occur after removal of the FoxO1 transcriptional inhibitor from the FoxO-recognized element in the elastin gene promoter. In addition, insulin signaling facilitates the association of tropoelastin with its specific 67-kDa elastin-binding protein/spliced form of β-galactosidase chaperone, enhancing secretion. These results are crucial to understanding of the molecular and cellular mechanisms of diabetes-associated vascular disease, and, in particular, endorse use of insulin therapy for treatment of atherosclerotic lesions in patients with type 1 diabetes, in which induction of new elastic fibers would mechanically stabilize the developing plaques and prevent arterial occlusions.
authors.affiliation: Division of Cardiovascular Research, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Junyan
authors.initials: J
authors.lastname: Shi
authors.forename: Andrew
authors.initials: A
authors.lastname: Wang
authors.forename: Sanjana
authors.initials: S
authors.lastname: Sen
authors.forename: Yanting
authors.initials: Y
authors.lastname: Wang
authors.forename: Hyunjun J
authors.initials: HJ
authors.lastname: Kim
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Mitts
authors.forename: Aleksander
authors.initials: A
authors.lastname: Hinek
mesh_terms: D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D002867:Chromones / Q000494:pharmacology; D004549:Elastin / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005696:Galactosidases / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000187:drug effects; D014333:Tropoelastin / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D002867:Chromones; D004791:Enzyme Inhibitors; D007328:Insulin; D009025:Morpholines; C455479:RBFOX1 protein, human; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D014333:Tropoelastin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D004549:Elastin; D019869:Phosphatidylinositol 3-Kinases; D005696:Galactosidases