title: Oncostatin M-mediated regulation of KIT-ligand-induced extracellular signal-regulated kinase signaling maintains hematopoietic repopulating activity of Lin-CD34+CD133+ cord blood cells.
abstract: We investigated whether KIT signaling was sufficient to maintain human hematopoietic stem cells in culture or whether, as with murine stem cells, signaling through glycoprotein 130 (gp130) is additionally required. Sorted CD34(+)CD133(+)(CD33/CD38/CD71)(-) cells from human umbilical cord blood (UCB) were cultured in the presence of combinations of KIT-ligand (KL) and the gp130 stimulating molecule oncostatin M (OSM). We found that OSM increased KL-induced proliferation, which was accompanied by an expansion in numbers of mature progenitors colony-forming cells (CFC, CAFCw2). More primitive progenitors, CAFCw6 and long-term culture-CFC, were not maintained by KL as a single factor. Although addition of OSM did not improve survival, the KL/OSM combination showed improved maintenance of immature progenitors as well as higher CD34 expression. Similarly, both KL and OSM were required to maintain NOD/SCID-repopulating activity. In experiments to investigate the underlying mechanism, we found that extracellular signal-regulated kinase (ERK) and its downstream target p90 ribosomal S6 kinase were activated by KL and downregulated by the inclusion of OSM during stimulation. The p38 mitogen-activated protein kinase (p38 MAPK) was not modulated by either KL or OSM. Indeed, many of the effects of OSM (increased cell division, maintenance of CFC, and maintenance of high CD34 expression) could be mimicked by using the mitogen-activated protein kinase kinase inhibitor U0126. More importantly, NOD/SCID-repopulating activity was preserved in the KL/U0126-stimulated cells, but not in cells stimulated with a combination of KL and the p38 MAPK inhibitor SB203580. Our results show that the loss of repopulating activity during KL stimulation is counteracted by OSM through the downregulation of ERK pathway signaling. Disclosure of potential conflicts of interest is found at the end of this article.
authors.affiliation: Laboratory of Stem Cell Physiology, III. Medizinische Klinik und Poliklinik, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675 Munchen, Germany. oostendorp@lrz.tum.de
authors.forename: Robert A J
authors.initials: RA
authors.lastname: Oostendorp
authors.forename: Siv
authors.initials: S
authors.lastname: Gilfillan
authors.forename: Amanda
authors.initials: A
authors.lastname: Parmar
authors.forename: Matthias
authors.initials: M
authors.lastname: Schiemann
authors.forename: Stefanie
authors.initials: S
authors.lastname: Marz
authors.forename: Markus
authors.initials: M
authors.lastname: Niemeyer
authors.forename: Sabine
authors.initials: S
authors.lastname: Schill
authors.forename: Edelburga
authors.initials: E
authors.lastname: Hammerschmid
authors.forename: Volker R
authors.initials: VR
authors.lastname: Jacobs
authors.forename: Christian
authors.initials: C
authors.lastname: Peschel
authors.forename: Katharina S
authors.initials: KS
authors.lastname: Götze
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis*; D018952:Antigens, CD34 / Q000096:biosynthesis*; D016895:Culture Media, Serum-Free / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005312:Fetal Blood / Q000166:cytology*; D006023:Glycoproteins / Q000096:biosynthesis*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D053683:Oncostatin M / Q000378:metabolism*; D010455:Peptides; D015398:Signal Transduction; D019089:Stem Cell Factor / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D016895:Culture Media, Serum-Free; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; D019089:Stem Cell Factor; D053683:Oncostatin M; D048049:Extracellular Signal-Regulated MAP Kinases