title: TGF-β mediates early angiogenesis and latent fibrosis in an Emilin1-deficient mouse model of aortic valve disease.
abstract: Aortic valve disease (AVD) is characterized by elastic fiber fragmentation (EFF), fibrosis and aberrant angiogenesis. Emilin1 is an elastin-binding glycoprotein that regulates elastogenesis and inhibits TGF-β signaling, but the role of Emilin1 in valve tissue is unknown. We tested the hypothesis that Emilin1 deficiency results in AVD, mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β dysregulation. Using histology, immunohistochemistry, electron microscopy, quantitative gene expression analysis, immunoblotting and echocardiography, we examined the effects of Emilin1 deficiency (Emilin1-/-) in mouse aortic valve tissue. Emilin1 deficiency results in early postnatal cell-matrix defects in aortic valve tissue, including EFF, that progress to latent AVD and premature death. The Emilin1-/- aortic valve displays early aberrant provisional angiogenesis and late neovascularization. In addition, Emilin1-/- aortic valves are characterized by early valve interstitial cell activation and proliferation and late myofibroblast-like cell activation and fibrosis. Interestingly, canonical TGF-β signaling (phosphorylated Smad2 and Smad3) is upregulated constitutively from birth to senescence, whereas non-canonical TGF-β signaling (phosphorylated Erk1 and Erk2) progressively increases over time. Emilin1 deficiency recapitulates human fibrotic AVD, and advanced disease is mediated by non-canonical (MAPK/phosphorylated Erk1 and Erk2) TGF-β activation. The early manifestation of EFF and aberrant angiogenesis suggests that these processes are crucial intermediate factors involved in disease progression and therefore might provide new therapeutic targets for human AVD.
authors: Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Charu
authors: C
authors: Munjal
authors: Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Amy M
authors: AM
authors: Opoka
authors: Division of Molecular Cardiovascular Biology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Hanna
authors: H
authors: Osinska
authors: Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors: Jeanne F
authors: JF
authors: James
authors: Department of Molecular Medicine, University of Padua, 35121 Padua, Italy.
authors: Giorgio M
authors: GM
authors: Bressan
authors: Division of Cardiology, The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA robert.hinton@cchmc.org.
authors: Robert B
authors: RB
authors: Hinton
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D000082882:Bicuspid Aortic Valve Disease; D002114:Calcinosis / Q000150:complications / Q000473:pathology; D049109:Cell Proliferation; D003483:Cutis Laxa / Q000473:pathology; D004195:Disease Models, Animal; D018450:Disease Progression; D004547:Elastic Tissue / Q000378:metabolism; D005355:Fibrosis; D006330:Heart Defects, Congenital / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D006349:Heart Valve Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D007249:Inflammation / Q000150:complications / Q000473:pathology; D008562:Membrane Glycoproteins / Q000172:deficiency* / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D058628:Myofibroblasts / Q000378:metabolism / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014463:Ultrasonography
chemical_list: D008562:Membrane Glycoproteins; D016212:Transforming Growth Factor beta; C030340:elastin microfibril interface located protein
keywords: Angiogenesis; Aortic valve; Elastic fibers; Extracellular matrix; Fibrosis