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Identification of unipotent megakaryocyte progenitors in human hematopoiesis

Kohta Miyawaki, Hiromi Iwasaki, Takashi Jiromaru, Hirotake Kusumoto, Ayano Yurino, Takeshi Sugio, Yasufumi Uehara, Jun Odawara, Shinya Daitoku, Yuya Kunisaki, Yasuo Mori, Yojiro Arinobu, Hirofumi Tsuzuki, Yoshikane Kikushige, Tadafumi Iino, Koji Kato, Katsuto Takenaka, Toshihiro Miyamoto, Takahiro Maeda and Koichi Akashi

Key Points

  • A prospectively isolatable and functionally homogeneous human megakaryocyte progenitor population resides in CMP fraction of adult bone marrow.

  • This newly identified unipotent megakaryocyte progenitor significantly contributes to normal and malignant megakaryopoiesis.

Publisher's Note: There is an Inside Blood Commentary on this article in this issue.

Abstract

The developmental pathway for human megakaryocytes remains unclear, and the definition of pure unipotent megakaryocyte progenitor is still controversial. Using single-cell transcriptome analysis, we have identified a cluster of cells within immature hematopoietic stem- and progenitor-cell populations that specifically expresses genes related to the megakaryocyte lineage. We used CD41 as a positive marker to identify these cells within the CD34+CD38+IL-3RαdimCD45RA common myeloid progenitor (CMP) population. These cells lacked erythroid and granulocyte-macrophage potential but exhibited robust differentiation into the megakaryocyte lineage at a high frequency, both in vivo and in vitro. The efficiency and expansion potential of these cells exceeded those of conventional bipotent megakaryocyte/erythrocyte progenitors. Accordingly, the CD41+ CMP was defined as a unipotent megakaryocyte progenitor (MegP) that is likely to represent the major pathway for human megakaryopoiesis, independent of canonical megakaryocyte-erythroid lineage bifurcation. In the bone marrow of patients with essential thrombocythemia, the MegP population was significantly expanded in the context of a high burden of Janus kinase 2 mutations. Thus, the prospectively isolatable and functionally homogeneous human MegP will be useful for the elucidation of the mechanisms underlying normal and malignant human hematopoiesis.

  • Submitted September 27, 2016.
  • Accepted March 13, 2017.
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