SLAM Family Receptors Distinguish Hematopoietic Stem and Progenitor Cells and Reveal Endothelial Niches for Stem Cells
ABSTRACT To improve our ability to identify hematopoietic stem cells (HSCs) and their localization in vivo, we compared the gene expression profiles of highly purified HSCs and non-self-renewing multipotent hematopoietic progenitors (MPPs). Cell surface receptors of the SLAM family, including CD150, CD244, and CD48, were differentially expressed among functionally distinct progenitors. HSCs were highly purified as CD150(+)CD244(-)CD48(-) cells while MPPs were CD244(+)CD150(-)CD48(-) and most restricted progenitors were CD48(+)CD244(+)CD150(-). The primitiveness of hematopoietic progenitors could thus be predicted based on the combination of SLAM family members they expressed. This is the first family of receptors whose combinatorial expression precisely distinguishes stem and progenitor cells. The ability to purify HSCs based on a simple combination of SLAM receptors allowed us to identify HSCs in tissue sections. Many HSCs were associated with sinusoidal endothelium in spleen and bone marrow, though some HSCs were associated with endosteum. HSCs thus occupy multiple niches, including sinusoidal endothelium in diverse tissues.
- SourceAvailable from: Boris Michael Holzapfel
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- "Staining for tartrate resistant acid phosphatase (TRAP, red) B.M. Holzapfel et al. / Biomaterials 61 (2015) 103e114 104 multi-potency and long-term reconstitution . The endosteal  , mesenchymal   and vascular systems  have been identified as the main regulating components of the HSC niches, nevertheless the concept of the niche embodies the physical entity of all its single constituents . In the last years, researchers have become more aware of the fact that the niche itself can be a driver for pathogenesis, particularly in bone metastatic disease or leukemia  . "
ABSTRACT: Advances in tissue-engineering have resulted in a versatile tool-box to specifically design a tailored microenvironment for hematopoietic stem cells (HSCs) in order to study diseases that develop within this setting. However, most current in vivo models fail to recapitulate the biological processes seen in humans. Here we describe a highly reproducible method to engineer humanized bone constructs that are able to recapitulate the morphological features and biological functions of the HSC niches. Ectopic implantation of biodegradable composite scaffolds cultured for 4 weeks with human mesenchymal progenitor cells and loaded with rhBMP-7 resulted in the development of a chimeric bone organ including a large number of human mesenchymal cells which were shown to be metabolically active and capable of establishing a humanized microenvironment supportive of the homing and maintenance of human HSCs. A syngeneic mouse-to-mouse transplantation assay was used to prove the functionality of the tissue-engineered ossicles. We predict that the ability to tissue engineer a morphologically intact and functional large-volume bone organ with a humanized bone marrow compartment will help to further elucidate physiological or pathological interactions between human HSCs and their native niches. Copyright © 2015. Published by Elsevier Ltd.Biomaterials 08/2015; 61:103 - 114. DOI:10.1016/j.biomaterials.2015.04.057 · 8.31 Impact Factor
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- "Here, we showed that phenotypic heterogeneity was present in the resting blood CD34þ cells from LRS chambers. Most CD34þCD45 low cells from peripheral blood were positive for CD38 and CD244, indicating their commitment toward differentiation  . In addition, these cells were also positive for the transferrin receptor CD71. "
ABSTRACT: For transplantation, hematopoietic stem cells (HSC) are obtained from bone marrow, cord blood and mobilized adult peripheral blood. HSCs are present in the blood of healthy adults and can be recovered in leuko-reduction system chambers, with a potential yield of 1 to 4 × 10(6) CD34+ cells per unit. Some groups have investigated this valuable source of stem cells; however, investigations are still needed to support their use. CD34+ cells were purified from leuko-reduction system chambers and cultured with a defined custom medium without animal protein and supplemented with interleukin-3, interleukin-6, Fms-like tyrosine kinase 3, stem cell factor and thrombopoietin. Cells were cultured under 8% and 21% oxygen levels. With the use of multiparametric flow cytometry analysis, the phenotypes of emerging populations were compared between oxygen levels and resting CD34+ cells. Both conventional gating and clustering analysis were used to visualize the cellular outcome. A maximum expansion of 20-fold was obtained without major differences in viability, number of cells or cellular heterogeneity between atmospheric and physiologic oxygen conditions. Worthy of note, phenotype analysis revealed that megakaryocyte and erythrocyte progenitors were favored, albeit more moderately when submitted to 8% O2. This study suggests that the bias of cultured blood CD34+ cells toward megakaryocyte and erythrocyte progenitor cells can be reduced by use of 8% pO2. It also shows how clustering software, such as SPADE, can help visualize the complexity of stem cell differentiation. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.Cytotherapy 07/2015; DOI:10.1016/j.jcyt.2015.05.006 · 3.10 Impact Factor
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- "During stem cell homing, HSCs expressing CXCR-4 are attracted to the osteoblastic niche, which expresses high levels of SDF-1 (Kopp et al., 2005). HSCs expressing signaling lymphocyte activation molecule markers were detected on the osteoblastic surface of trabecular bone as well as adjacent to sinusoidal ECs (Kiel et al., 2005). Hematopoiesis is severely altered in conditionally transgenic mice, which exhibit osteoblast deficiency (Visnjic et al., 2004). "
ABSTRACT: Bone marrow (BM) contains hematopoietic stem cells (HSCs) and nonhematopoietic cells. HSCs give rise to all types of mature blood cells, while the nonhematopoietic component includes osteoblasts/osteoclasts, endothelial cells (ECs), endothelial progenitor cells (EPCs), and mesenchymal stem cells (MSCs). These cells form specialized "niches" which are close to the vasculature ("vascular niche") or to the endosteum ("osteoblast niche"). The "vascular niche", rich in blood vessels where ECs and mural cells (pericytes and smooth muscle cells), create a microenvironment affecting the behavior of several stem and progenitor cells. The vessel wall acts as an independent niche for the recruitment of EPCs and MSCs. This chapter will focus on the description of the role of BM niches in the control of angiogenesis occurring during multiple myeloma progression. Copyright © 2015 Elsevier Inc. All rights reserved.International review of cell and molecular biology 01/2015; 314:259-82. DOI:10.1016/bs.ircmb.2014.10.004 · 4.52 Impact Factor