title: Role of GM-CSF in tolerance induction by mobilized hematopoietic progenitors.
abstract: Mechanisms of protection against autoimmune diseases by transplantation of autologous hematopoietic progenitors remain poorly defined. We recently demonstrated that, unlike medullary hematopoietic stem cells (HSCs), mobilized hematopoietic progenitors (HPCs) stimulate peripheral Foxp3(+) regulatory T cell (Treg)-expansion through cell-contact activation of Notch signaling and through as yet undetermined soluble factor(s), distinct from TGF-beta1. Herein we identified one such soluble factor as granulocyte macrophage-colony stimulating factor (GM-CSF), which is produced at higher levels by HPCs than HSCs and whose neutralization significantly reduces the growth-promoting effect of HPCs on Treg. Treg express a functional GM-CSF receptor alpha-chain CD116 and proliferate in response to this cytokine independently from IL2. GM-CSF-expanded Treg-like HPC-expanded Treg-display enhanced suppressive capacity relative to control Treg. Hence, mobilized progenitors stimulate Treg expansion both by cell-contact dependent mechanisms and by their production of GM-CSF.
authors.affiliation: Université Paris Descartes, Faculté de Médecine, Centre National de la Recherche Scientifique UMR 8147, France.
authors.forename: Hassen
authors.initials: H
authors.lastname: Kared
authors.forename: Bertrand
authors.initials: B
authors.lastname: Leforban
authors.forename: Ruddy
authors.initials: R
authors.lastname: Montandon
authors.forename: Amédée
authors.initials: A
authors.lastname: Renand
authors.forename: Esther
authors.initials: E
authors.lastname: Layseca Espinosa
authors.forename: Lucienne
authors.initials: L
authors.lastname: Chatenoud
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Rosenstein
authors.forename: Elke
authors.initials: E
authors.lastname: Schneider
authors.forename: Michel
authors.initials: M
authors.lastname: Dy
authors.forename: Flora
authors.initials: F
authors.lastname: Zavala
mesh_terms: D000818:Animals; D002450:Cell Communication; D049109:Cell Proliferation; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D007108:Immune Tolerance; D051379:Mice; D016688:Mice, Inbred NOD; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D050378:T-Lymphocytes, Regulatory / Q000166:cytology
chemical_list: D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor