Graduate School of Frontier Biosciences, Osaka University

Japanese

Stem cell niche-specific Ebf3 maintains the bone marrow cavity

Journal Genes Dev 32, 5-6 (2018)
Authors Seike M (1), Omatsu Y (1), Watanabe H (2), Kondoh G (2), Nagasawa T (1)
  1. Laboratory of Stem Cell Biology and Developmental Immunology, Graduate School of Frontier Biosciences, Graduate School of Medicine, Immunology Frontier Research Center, World Premier International Research Center (WPI), Osaka University, Osaka 565-0871, Japan.
  2. Laboratory of Integrative Biological Science and Animal Experiments for Regeneration, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
Title Stem cell niche-specific Ebf3 maintains the bone marrow cavity
PubMed 29563184
Laboratory Laboratory of Stem Cell Biology and Developmental Immunology 〈Prof. Nagasawa〉
Description Bone marrow is the tissue filling the space between bone surfaces. Hematopoietic stem cells (HSCs) are maintained by special microenvironments known as niches within bone marrow cavities. Mesenchymal cells, termed CXC chemokine ligand 12 (CXCL12)-abundant reticular (CAR) cells or leptin receptor-positive (LepR+) cells, are a major cellular component of HSC niches that gives rise to osteoblasts in bone marrow. However, it remains unclear how osteogenesis is prevented in most CAR/LepR+ cells to maintain HSC niches and marrow cavities. Here, using lineage tracing, we found that the transcription factor early B-cell factor 3 (Ebf3) is preferentially expressed in CAR/LepR+ cells and that Ebf3-expressing cells are self-renewing mesenchymal stem cells in adult marrow. When Ebf3 is deleted in CAR/LepR+ cells, HSC niche function is severely impaired, and bone marrow is osteosclerotic with increased bone in aged mice. In mice lacking Ebf1 and Ebf3, CAR/LepR+ cells exhibiting a normal morphology are abundantly present, but their niche function is markedly impaired with depleted HSCs in infant marrow. Subsequently, the mutants become progressively more osteosclerotic, leading to the complete occlusion of marrow cavities in early adulthood. CAR/LepR+ cells differentiate into bone-producing cells with reduced HSC niche factor expression in the absence of Ebf1/Ebf3 Thus, HSC cellular niches express Ebf3 that is required to create HSC niches, to inhibit their osteoblast differentiation, and to maintain spaces for HSCs.