title: Nitric oxide synthase 2 is required for conversion of pro-fibrogenic inflammatory CD133(+) progenitors into F4/80(+) macrophages in experimental autoimmune myocarditis.
abstract: OBJECTIVE
  Experimental autoimmune myocarditis (EAM) model mirrors important mechanisms of inflammatory dilated cardiomyopathy (iDCM). In EAM, inflammatory CD133(+) progenitors are a major cellular source of cardiac myofibroblasts in the post-inflammatory myocardium. We hypothesized that exogenous delivery of macrophage-colony-stimulating factor (M-CSF) can stimulate macrophage lineage differentiation of inflammatory progenitors and, therefore, prevent their naturally occurring myofibroblast fate in EAM.
  
  
  RESULTS
  EAM was induced in wild-type (BALB/c) and nitric oxide synthase 2-deficient (Nos2(-/-)) mice and CD133(+) progenitors were isolated from inflamed hearts. In vitro, M-CSF converted inflammatory CD133(+) progenitors into nitric oxide-producing F4/80(+) macrophages and prevented transforming growth factor-β-mediated myofibroblast differentiation. Importantly, only a subset of heart-infiltrating CD133(+) progenitors expresses macrophage-specific antigen F4/80 in EAM. These CD133(+)/F4/80(hi) cells show impaired myofibrogenic potential compared with CD133(+)/F4/80(-) cells. M-CSF treatment of wild-type mice with EAM at the peak of disease markedly increased CD133(+)/F4/80(hi) cells in the myocardium, and CD133(+) progenitors isolated from M-CSF-treated mice failed to differentiate into myofibroblasts. In contrast, M-CSF was not effective in converting CD133(+) progenitors from inflamed hearts of Nos2(-/-) mice into macrophages, and M-CSF treatment did not result in increased CD133(+)/F4/80(hi) cell population in hearts of Nos2(-/-) mice. Accordingly, M-CSF prevented post-inflammatory fibrosis and left ventricular dysfunction in wild-type but not in Nos2(-/-) mice.
  
  
  CONCLUSIONS
  Active and NOS2-dependent induction of macrophage lineage differentiation abrogates the myofibrogenic potential of heart-infiltrating CD133(+) progenitors. Modulating the in vivo differentiation fate of specific progenitors might become a novel approach for the treatment of inflammatory heart diseases.
authors.affiliation: Cardioimmunology, Cardiovascular Research and Zürich Center for Integrative Human Physiology,  Institute of Physiology, University of Zürich, Winterthurerstr. 190, Zürich CH-8057,  Switzerland.
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Blyszczuk
authors.forename: Corrine
authors.initials: C
authors.lastname: Berthonneche
authors.forename: Silvia
authors.initials: S
authors.lastname: Behnke
authors.forename: Marcel
authors.initials: M
authors.lastname: Glönkler
authors.forename: Holger
authors.initials: H
authors.lastname: Moch
authors.forename: Thierry
authors.initials: T
authors.lastname: Pedrazzini
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lüscher
authors.forename: Urs
authors.initials: U
authors.lastname: Eriksson
authors.forename: Gabriela
authors.initials: G
authors.lastname: Kania
mesh_terms: D000071916:AC133 Antigen; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000943:Antigens, Differentiation / Q000032:analysis*; D001327:Autoimmune Diseases / Q000473:pathology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D005355:Fibrosis; D006023:Glycoproteins / Q000032:analysis*; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009205:Myocarditis / Q000473:pathology*; D009206:Myocardium / Q000473:pathology; D052247:Nitric Oxide Synthase Type II / Q000502:physiology*; D010455:Peptides / Q000032:analysis*; D013234:Stem Cells / Q000166:cytology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D018487:Ventricular Dysfunction, Left / Q000517:prevention & control
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D000943:Antigens, Differentiation; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; D016212:Transforming Growth Factor beta; C036763:monocyte-macrophage differentiation antigen; D016173:Macrophage Colony-Stimulating Factor; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse