title: Inflammatory cytokines promote mesenchymal transformation in embryonic and adult valve endothelial cells.
abstract: OBJECTIVE
  Inflammatory activation of valve endothelium is an early phase of aortic valve disease pathogenesis, but subsequent mechanisms are poorly understood. Adult valve endothelial cells retain the developmental ability to undergo endothelial-to-mesenchymal transformation (EndMT), but a biological role has not been established. Here, we test whether and how inflammatory cytokines (tumor necrosis factor-α and interleukin-6) regulate EndMT in embryonic and adult valve endothelium.
  
  
  RESULTS
  Using in vitro 3-dimensional collagen gel culture assays with primary cells, we determined that interleukin-6 and tumor necrosis factor-α induce EndMT and cell invasion in dose-dependent manners. Inflammatory-EndMT occurred through an Akt/nuclear factor-κB-dependent pathway in both adult and embryonic stages. In embryonic valves, inflammatory-EndMT required canonical transforming growth factor-β signaling through activin receptor-like kinases 2 and 5 to drive EndMT. In adult valve endothelium, however, inflammatory-induced EndMT still occurred when activin receptor-like kinases 2 and 5 signaling was blocked. Inflammatory receptor gene expression was significantly upregulated in vivo during embryonic valve maturation. Endothelial-derived mesenchymal cells expressing activated nuclear factor-κB were found distal to calcific lesions in diseased human aortic valves.
  
  
  CONCLUSIONS
  Inflammatory cytokine-induced EndMT in valve endothelium is present in both embryonic and adult stages, acting through Akt/nuclear factor-κB, but differently using transforming growth factor-β signaling. Molecular signatures of valve EndMT may be important diagnostic and therapeutic targets in early valve disease.
authors.affiliation: Department of Bioengineering, Binghamton University, Binghamton, NY, USA.
authors.forename: Gretchen J
authors.initials: GJ
authors.lastname: Mahler
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Farrar
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Butcher
mesh_terms: D030201:Activin Receptors, Type I / Q000378:metabolism; D000818:Animals; D001021:Aortic Valve / Q000196:embryology / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002114:Calcinosis / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D002465:Cell Movement; D002478:Cells, Cultured; D002642:Chick Embryo; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005786:Gene Expression Regulation; D006349:Heart Valve Diseases / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D061251:Primary Cell Culture; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011784:Quail; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D013997:Time Factors; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016328:NF-kappa B; D018125:Receptors, Transforming Growth Factor beta; D011994:Recombinant Proteins; D053773:Transforming Growth Factor beta1; D014409:Tumor Necrosis Factor-alpha; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I