title: Hematopoietic stem cell niche: an interplay among a repertoire of multiple functional niches.
abstract: BACKGROUND
  Hematopoietic stem cell (HSC) niche of the BM provides a specialized microenvironment for the regulation of HSCs. The strict control of HSCs by the niche coordinates the balance between the proliferation and the differentiation of HSCs for the homeostasis of the blood system in steady states and during stress hematopoiesis. The osteoblastic and vascular niches are the classically identified constituents of the BM niche.
  
  
  METHODS
  Recent research broadens our understanding of the BM niche as an assembly of multiple niche cells within the BM. We provide an overview of the HSC niche aiming to delineate the defined and possible niche cell interactions which collectively modulate the HSC integrity.
  
  
  CONCLUSIONS
  Multiple cells in the BM, including osteoblasts, vascular endothelia, perivascular mesenchymal cells and HSC progeny cells, function conjunctively as niche cells to regulate HSCs.
  
  
  CONCLUSIONS
  The study of HSC niche cells and their functions provides insights into stem cell biology and also may be extrapolated into the study of cancer stem cells. This article is part of a Special Issue entitled Biochemistry of Stem Cells.
authors.affiliation: Department of Cell Differentiation, The Sakaguchi Laboratory, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. ayaknakm@a3.keio.jp
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakamura-Ishizu
authors.forename: Toshio
authors.initials: T
authors.lastname: Suda
mesh_terms: D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans