title: Prominent role of TGF-beta 1 in thrombopoietin-induced myelofibrosis in mice.
abstract: Several studies suggest an implication of transforming growth factor-beta1 (TGF-beta1) in the promotion of myelofibrosis associated with hematopoietic malignancies, but the involvement of this cytokine is not fully investigated. To test directly the impact of TGF-beta1 in the pathogenesis of myelofibrosis, bone marrow stem cells from homozygous TGF-beta1 null (TGF-beta1(-/-)) and wild-type (WT) littermates were infected with a retrovirus encoding the murine thrombopoietin (TPO) protein and engrafted into lethally irradiated wild-type hosts for long-term reconstitution. Over the 4 months of follow-up, TPO levels in plasma were markedly elevated in both groups of mice, and animals typically developed a myeloproliferative syndrome characterized by thrombocytosis, leukocytosis, splenomegaly, increased numbers of progenitors in blood, and extramedullary hematopoiesis. Severe fibrosis was observed in spleen and marrow from all the mice engrafted with WT cells. In contrast, none of the mice repopulated with TGF-beta1(-/-) cells (chimerism > 70%) showed deposition of reticulin fibers at any time during the follow-up. In accordance with the development of fibrosis, latent TGF-beta1 levels in plasma and extracellular fluid of the spleen from mice engrafted with WT cells were increased 6-fold and 4-fold, respectively, over levels found in normal hosts, whereas no increase over baseline levels could be demonstrated in animals undergoing transplantation with TGF-beta1(-/-) cells. These data provide evidence that TGF-beta1 produced by hematopoietic cells is pivotal for the pathogenesis of myelofibrosis that develops in mice with TPO overexpression.
authors.affiliation: INSERM U362, Institut Gustave Roussy, Villejuif, France.
authors.forename: Hédia
authors.initials: H
authors.lastname: Chagraoui
authors.forename: Emiko
authors.initials: E
authors.lastname: Komura
authors.forename: Micheline
authors.initials: M
authors.lastname: Tulliez
authors.forename: Stéphane
authors.initials: S
authors.lastname: Giraudier
authors.forename: William
authors.initials: W
authors.lastname: Vainchenker
authors.forename: Françoise
authors.initials: F
authors.lastname: Wendling
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects; D005260:Female; D006085:Graft Survival; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009196:Myeloproliferative Disorders / Q000209:etiology; D055728:Primary Myelofibrosis / Q000139:chemically induced* / Q000209:etiology / Q000473:pathology; D013926:Thrombopoietin / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D014161:Transduction, Genetic; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D053773:Transforming Growth Factor beta1
chemical_list: C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D013926:Thrombopoietin