title: Podoplanin-positive periarteriolar stromal cells promote megakaryocyte growth and proplatelet formation in mice by CLEC-2.
abstract: Megakaryopoiesis is the hierarchical differentiation of hematopoietic stem cells into megakaryocytes. Differentiating megakaryocytes undergo maturation characterized by endomitosis and produce numerous platelets through proplatelet formation. C-type lectin-like receptor 2 (CLEC-2) is a podoplanin (PDPN) receptor mainly expressed on platelets and megakaryocytes. Deletion of platelet/megakaryocyte CLEC-2 causes thrombocytopenia in mice; however, its contribution to megakaryopoiesis remains unknown. Here, we show that megakaryopoiesis is promoted through the CLEC-2/PDPN interaction in the vicinity of arterioles in the bone marrow (BM). We have also identified PDPN-expressing BM arteriolar stromal cells, tentatively termed as BM fibroblastic reticular cell (FRC)-like cells. Platelet/megakaryocyte-specific CLEC-2 conditional knockout (cKO) mice showed a decrease in the number of immature megakaryocytes. CLEC-2 wild-type megakaryocyte expansion was augmented in vitro by the addition of recombinant PDPN, but not cKO megakaryocytes. Moreover, megakaryocyte colonies were colocalized with periarteriolar BM FRC-like cells in the BM. Coculture of megakaryocytes with BM FRC-like cells augmented megakaryocyte expansion, which was dependent upon the CLEC-2/PDPN interaction. Furthermore, we found that the CLEC-2/PDPN interaction induces BM FRC-like cells to secrete chemokine (C-C motif) ligand 5 (CCL5) to facilitate proplatelet formation. These observations indicate that a reciprocal interaction between CLEC-2 on megakaryocytes and PDPN on BM FRC-like cells contributes to the periarteriolar megakaryopoietic microenvironment in mouse BM.
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan; Japan Society for the Promotion of Science, Tokyo, Japan; and.
authors.forename: Shogo
authors.initials: S
authors.lastname: Tamura
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan;
authors.forename: Katsue
authors.initials: K
authors.lastname: Suzuki-Inoue
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan;
authors.forename: Nagaharu
authors.initials: N
authors.lastname: Tsukiji
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan;
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Shirai
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan;
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Division of Laboratory Medicine, University of Yamanashi Hospital, Chuo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Osada
authors.affiliation: Division of Laboratory Medicine, University of Yamanashi Hospital, Chuo, Japan.
authors.forename: Kaneo
authors.initials: K
authors.lastname: Satoh
authors.affiliation: Department of Laboratory and Medicine, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan;
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ozaki
mesh_terms: D000818:Animals; D001160:Arterioles / Q000166:cytology / Q000502:physiology; D001792:Blood Platelets / Q000502:physiology*; D001854:Bone Marrow Cells / Q000166:cytology; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D037181:Lectins, C-Type / Q000235:genetics / Q000502:physiology*; D008533:Megakaryocytes / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017154:Stromal Cells / Q000378:metabolism / Q000502:physiology*; D034061:Thrombopoiesis / Q000235:genetics*; D000098853:Podoplanin
chemical_list: D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; C529518:CLEC-2 protein, mouse; C490441:Pdpn protein, mouse; D000098853:Podoplanin