イシズ　アヤコ   Ishizu Ayako   石津　綾子    所属   医学部 医学科    職種   教授・基幹分野長
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	CLEC-2 in megakaryocytes is critical for maintenance of hematopoietic stem cells in the bone marrow.
掲載誌名	正式名：The Journal of experimental medicine 略　 称：J Exp Med ISSNコード：15409538/00221007
掲載区分	国外
巻・号・頁	212(12),pp.2133-46
著者・共著者	Nakamura-Ishizu Ayako, Takubo Keiyo, Kobayashi Hiroshi, Suzuki-Inoue Katsue, Suda Toshio
発行年月	2015/11
概要	Hematopoietic stem cells (HSCs) depend on the bone marrow (BM) niche for their maintenance, proliferation, and differentiation. The BM niche is composed of nonhematopoietic and mature hematopoietic cells, including megakaryocytes (Mks). Thrombopoietin (Thpo) is a crucial cytokine produced by BM niche cells. However, the cellular source of Thpo, upon which HSCs primarily depend, is unclear. Moreover, no specific molecular pathway for the regulation of Thpo production in the BM has been identified. Here, we demonstrate that the membrane protein C-type lectin-like receptor-2 (CLEC-2) mediates the production of Thpo and other factors in Mks. Mice conditionally deleted for CLEC-2 in Mks (Clec2(MkΔ/Δ)) produced lower levels of Thpo in Mks. CLEC-2-deficient Mks showed down-regulation of CLEC-2-related signaling molecules Syk, Lcp2, and Plcg2. Knockdown of these molecules in cultured Mks decreased expression of Thpo. Clec2(MkΔ/Δ) mice exhibited reduced BM HSC quiescence and repopulation potential, along with extramedullary hematopoiesis. The low level of Thpo production may account for the decline in HSC potential in Clec2(MkΔ/Δ) mice, as administration of recombinant Thpo to Clec2(MkΔ/Δ) mice restored stem cell potential. Our study identifies CLEC-2 signaling as a novel molecular mechanism mediating the production of Thpo and other factors for the maintenance of HSCs.
DOI	10.1084/jem.20150057
PMID	26552707