title: CD41+/CD45+ cells without acetylcholinesterase activity are immature and a major megakaryocytic population in murine bone marrow.
abstract: Murine megakaryocytes (MKs) are defined by CD41/CD61 expression and acetylcholinesterase (AChE) activity; however, their stages of differentiation in bone marrow (BM) have not been fully elucidated. In murine lineage-negative (Lin(-))/CD45(+) BM cells, we found CD41(+) MKs without AChE activity (AChE(-)) except for CD41(++) MKs with AChE activity (AChE(+)), in which CD61 expression was similar to their CD41 level. Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs could differentiate into AChE(+), with an accompanying increase in CD41/CD61 during in vitro culture. Both proplatelet formation (PPF) and platelet (PLT) production for Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs were observed later than for Lin(-)/CD41(++)/CD45(+)/AChE(+) MKs, whereas MK progenitors were scarcely detected in both subpopulations. GeneChip and semiquantitative polymerase chain reaction analyses revealed that the Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs are assigned at the stage between the progenitor and PPF preparation phases in respect to the many MK/PLT-specific gene expressions, including beta1-tubulin. In normal mice, the number of Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs was 100 times higher than that of AChE(+) MKs in BM. When MK destruction and consequent thrombocytopenia were caused by an antitumor agent, mitomycin-C, Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs led to an increase in AChE(+) MKs and subsequent PLT recovery with interleukin-11 administration. It was concluded that MKs in murine BM at least in part consist of immature Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs and more differentiated Lin(-)/CD41(++)/CD45(+)/AChE(+) MKs. Immature Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs are a major MK population compared with AChE(+) MKs in BM and play an important role in rapid PLT recovery in vivo.
authors.affiliation: Molecular Medical Science Institute, Otsuka Pharmaceutical Co. Ltd., 463-10 Kagasuno, Tokushima, Japan.
authors.forename: Kuniko
authors.initials: K
authors.lastname: Matsumura-Takeda
authors.forename: Shinji
authors.initials: S
authors.lastname: Sogo
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Isakari
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Harada
authors.forename: Kinue
authors.initials: K
authors.lastname: Nishioka
authors.forename: Takuma
authors.initials: T
authors.lastname: Kawakami
authors.forename: Toshihide
authors.initials: T
authors.lastname: Ono
authors.forename: Takao
authors.initials: T
authors.lastname: Taki
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D018929:Cell Culture Techniques; D003114:Colony-Forming Units Assay; D020869:Gene Expression Profiling; D017493:Leukocyte Common Antigens / Q000235:genetics*; D008297:Male; D008533:Megakaryocytes / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D040201:Platelet Membrane Glycoprotein IIb / Q000235:genetics*; D016133:Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D040201:Platelet Membrane Glycoprotein IIb; D000110:Acetylcholinesterase; D017493:Leukocyte Common Antigens