title: BMP4 regulation of human megakaryocytic differentiation is involved in thrombopoietin signaling.
abstract: Activin A, BMP2, and BMP4, 3 members of the transforming growth factor-beta family, are involved in the regulation of hematopoiesis. Here, we explored the role of these molecules in human megakaryopoiesis using an in vitro serum-free assay. Our results highlight for the first time that, in the absence of thrombopoietin, BMP4 is able to induce CD34(+) progenitor differentiation into megakaryocytes through all stages. Although we have previously shown that activin A and BMP2 are involved in erythropoietic commitment, these molecules have no effect on human megakaryopoietic engagement and differentiation. Using signaling pathway-specific inhibitors, we show that BMP4, like thrombopoietin, exerts its effects on human megakaryopoiesis through the JAK/STAT and mTor pathways. Inhibition of the BMP signaling pathway with blocking antibodies, natural soluble inhibitors (FLRG or follistatin), or soluble BMP receptors reveals that thrombopoietin uses the BMP4 pathway to induce megakaryopoiesis, whereas the inverse is not occurring. Finally, we show that thrombopoietin up-regulates the BMP4 autocrine loop in megakaryocytic progenitors by inducing their production of BMP4 and up-regulating BMP receptor expression. In summary, this work indicates that BMP4 plays an important role in the control of human megakaryopoiesis.
authors.affiliation: Université de Lyon, Lyon, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Jeanpierre
authors.forename: Franck Emmanuel
authors.initials: FE
authors.lastname: Nicolini
authors.forename: Bastien
authors.initials: B
authors.lastname: Kaniewski
authors.forename: Charles
authors.initials: C
authors.lastname: Dumontet
authors.forename: Ruth
authors.initials: R
authors.lastname: Rimokh
authors.forename: Alain
authors.initials: A
authors.lastname: Puisieux
authors.forename: Véronique
authors.initials: V
authors.lastname: Maguer-Satta
mesh_terms: D028341:Activins / Q000378:metabolism; D018952:Antigens, CD34 / Q000096:biosynthesis; D001854:Bone Marrow Cells / Q000166:cytology; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002454:Cell Differentiation; D006801:Humans; D053613:Janus Kinase 1 / Q000378:metabolism; D008533:Megakaryocytes / Q000166:cytology; D008954:Models, Biological; D010976:Platelet Count; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases; D013926:Thrombopoietin / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D018952:Antigens, CD34; C525718:BMP2 protein, human; C525809:BMP4 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; C422405:activin A; D028341:Activins; D013926:Thrombopoietin; D011494:Protein Kinases; C546842:MTOR protein, human; D053613:Janus Kinase 1; D058570:TOR Serine-Threonine Kinases