@article{d4ed8db334334be68c7a63693acc60e1,
title = "Environmental Optimization Enables Maintenance of Quiescent Hematopoietic Stem Cells Ex Vivo",
abstract = "Hematopoietic stem cells (HSCs) maintain lifelong hematopoiesis by remaining quiescent in the bone marrow niche. Recapitulation of a quiescent state in culture has not been achieved, as cells rapidly proliferate and differentiate in vitro. After exhaustive analysis of different environmental factor combinations and concentrations as a way to mimic physiological conditions, we were able to maintain engraftable quiescent HSCs for 1 month in culture under very low cytokine concentrations, hypoxia, and very high fatty acid levels. Exogenous fatty acids were required likely due to suppression of intrinsic fatty acid synthesis by hypoxia and low cytokine conditions. By contrast, high cytokine concentrations or normoxia induced HSC proliferation and differentiation. Our culture system provides a means to evaluate properties of steady-state HSCs and test effects of defined factors in vitro under near-physiological conditions. Maintaining quiescent HSCs under physiological conditions facilitates evaluation of the properties of steady-state HSCs. Kobayashi et al. report that low cytokine concentrations, hypoxia, and high fatty acid levels mimicking the bone marrow microenvironment enable maintenance of engraftable quiescent HSCs for 1 month in culture.",
keywords = "fatty acid, hematopoietic stem cell, hypoxia, quiescence, stem cell culture, stem cell metabolism, stem cell niche",
author = "Hiroshi Kobayashi and Takayuki Morikawa and Ayumi Okinaga and Fumie Hamano and Tomomi Hashidate-Yoshida and Shintaro Watanuki and Daisuke Hishikawa and Hideo Shindou and Fumio Arai and Yasuaki Kabe and Makoto Suematsu and Takao Shimizu and Keiyo Takubo",
note = "Funding Information: We thank all members of the Takubo laboratory for indispensable support, M. Haraguchi and S. Tamaki for technical support and laboratory management, and E. Lamar for preparation of the manuscript. K.T. was supported in part by KAKENHI grants from MEXT/JSPS (26115005, 18H02845, 18K19570, 26115001, and 15K21751), a grant of the National Center for Global Health and Medicine (26-001, 29-2007), AMED-CREST (JP18gm0710010), an AMED grant for Realization of Regenerative Medicine (JP18bm0704011), an AMED grant (JP18ae0201014), and grants from the Japan Leukemia Research Fund, the Japan Rheumatism Foundation, the Takeda Science Foundation, the Senshin Medical Research Foundation, and the Japanese Society for Hematology. H.K. was supported in part by a KAKENHI grant (17K16200), a grant of the National Center for Global Health and Medicine (29-1015), and a grant from the Uehara Memorial Foundation. H.S. was supported in part by AMED-CREST (JP18gm0910011 and JP18gm0710002). M.S. was the leader of JST ERATO Suematsu Gas Biology until March 2015, which provided infrastructure for multi-photon laser confocal microscopy, essential to accomplish the aim of this current study. H.K. T.M. A.O. F.H. T.H.-Y. and S.W. performed the study and analyzed data; D.H. H.S. F.A. Y.K. M.S. and T.S. provided scientific advice and materials. H.K. and K.T. wrote the manuscript. K.T. conceived the project and supervised the research. The authors declare no competing interest. Funding Information: We thank all members of the Takubo laboratory for indispensable support, M. Haraguchi and S. Tamaki for technical support and laboratory management, and E. Lamar for preparation of the manuscript. K.T. was supported in part by KAKENHI grants from MEXT/JSPS ( 26115005 , 18H02845 , 18K19570 , 26115001 , and 15K21751 ), a grant of the National Center for Global Health and Medicine ( 26-001, 29-2007 ), AMED-CREST ( JP18gm0710010 ), an AMED grant for Realization of Regenerative Medicine ( JP18bm0704011 ), an AMED grant ( JP18ae0201014 ), and grants from the Japan Leukemia Research Fund , the Japan Rheumatism Foundation , the Takeda Science Foundation , the Senshin Medical Research Foundation , and the Japanese Society for Hematology . H.K. was supported in part by a KAKENHI grant ( 17K16200 ), a grant of the National Center for Global Health and Medicine ( 29-1015 ), and a grant from the Uehara Memorial Foundation . H.S. was supported in part by AMED-CREST ( JP18gm0910011 and JP18gm0710002 ). M.S. was the leader of JST ERATO Suematsu Gas Biology until March 2015, which provided infrastructure for multi-photon laser confocal microscopy, essential to accomplish the aim of this current study. Publisher Copyright: {\textcopyright} 2019 The Authors",
year = "2019",
month = jul,
day = "2",
doi = "10.1016/j.celrep.2019.06.008",
language = "English",
volume = "28",
pages = "145--158.e9",
journal = "Cell Reports",
issn = "2211-1247",
publisher = "Cell Press",
number = "1",
}