scholarly journals Maintenance of the Hematopoietic Stem Cell Pool by CXCL12-CXCR4 Chemokine Signaling in Bone Marrow Stromal Cell Niches

Immunity ◽  
2006 ◽  
Vol 25 (6) ◽  
pp. 977-988 ◽  
Author(s):  
Tatsuki Sugiyama ◽  
Hiroshi Kohara ◽  
Mamiko Noda ◽  
Takashi Nagasawa
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Stromal Cell ◽  
Bone Marrow Stromal Cell ◽  
Hematopoietic Stem ◽  
Marrow Stromal Cell ◽  
Cell Pool ◽  
Chemokine Signaling ◽  
Stem Cell Pool

The F-Box Protein NIPA Regulates the Hematopoietic Stem Cell Pool

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2330-2330
Author(s):  
Stefanie Kreutmair ◽  
Anna Lena Illert ◽  
Rouzanna Istvanffy ◽  
Melanie Sickinger ◽  
Christina Eckl ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Bone Marrow Cells ◽  
Wild Type ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
F Box Protein ◽  
Stem Cell Pool

Abstract Abstract 2330 Hematopoietic stem cells (HSCs) are characterized by their ability to self-renewal and multilineage differentiation. Since mostly HSCs exist in a quiescent state re-entry into cell cycle is essential for their regeneration and differentiation and the expression of numerous cell cycle regulators must be tightly controlled. We previously characterized NIPA (Nuclear Interaction Partner of ALK) as a F-Box protein that defines an oscillating ubiquitin E3 ligase targeting nuclear cyclin B1 in interphase thus contributing to the timing of mitotic entry. To examine the function of NIPA on vivo, we generated NIPA deficient animals, which are viable but sterile due to a defect in recombination and testis stem cell maintenance. To further characterize the role of NIPA in stem cell maintenance and self-renewal we investigated hematopoiesis in NIPA deficient animals. Peripheral blood counts taken at different ages revealed no apparent difference between NIPA knockout and wild type mice in numbers and differentiation. In contrast, looking at the hematopoietic stem cell pool, FACS analyses of bone marrow showed significantly decreased numbers of Lin-Sca1+cKit+ (LSK) cells in NIPA deficient animals, where LSKs were reduced to 40% of wild type littermates (p=0,0171). This effect was only apparent in older animals, where physiologically higher LSK numbers have to compensate for the exhaustion of the stem cell pool. Additionally, older NIPA deficient mice have only half the amount of multi myeloid progenitors (MMPs) in contrast to wild type animals. To examine efficient activation of stem cells to self-renew in response to myeloid depression, we treated young and old mice with the cytotoxic drug (5-FU) four days before bone marrow harvest. As expected, 5-FU activated hematopoietic progenitors in wild type animals, whereas NIPA deficient progenitors failed to compensate to 5-FU depression, e.g. LSKs of NIPA knockout mice were reduced to 50% of wild type levels (p<0.001), CD150+CD34+ Nipa deficient cells to 20% of wild type levels (p<0.0001). Interestingly, these effects were seen in all NIPA deficient animals independent of age, allowing us to trigger the self-renewal phenotype by activating the hematopoietic stem cell pool. Using competitive bone marrow transplantation assays, CD45.2 positive NIPA deficient or NIPA wild type bone marrow cells were mixed with CD45.1 positive wild type bone marrow cells and transplanted into lethally irradiated CD45.2 positive recipient mice. Thirty days after transplantation, FACS analysis of peripheral blood and bone marrow showed reduced numbers of NIPA knockout cells in comparison to NIPA wild type bone marrow recipient mice. This result was even more severe with aging of transplanted mice, where NIPA deficient cells were reduced to less than 10% of the level of wild type cells in bone marrow of sacrificed mice 6 months after transplantation, pointing to a profound defect in repopulation capacity of NIPA deficient HSCs. Taken together our results demonstrate a unique and critical role of NIPA in regulating the primitive hematopoietic compartment as a regulator of self-renewal, cycle capacity and HSC expansion. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Maintenance of the hematopoietic stem cell pool in bone marrow niches by EVI1-regulated GPR56

Leukemia ◽  
2013 ◽  
Vol 27 (8) ◽  
pp. 1637-1649 ◽  
Author(s):  
Y Saito ◽  
K Kaneda ◽  
A Suekane ◽  
E Ichihara ◽  
S Nakahata ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
Bone Marrow Niches ◽  
Stem Cell Pool

scholarly journals Deep Deconvolution of the Hematopoietic Stem Cell Regulatory Microenvironment Reveals a High Degree of Specialization and Conservation between Mouse and Human

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2168-2168
Author(s):  
Jin Ye ◽  
Isabel A Calvo ◽  
Itziar Cenzano ◽  
Amaia Vilas-Zornoza ◽  
Xabier Martinez-de-Morentin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Stromal Cells ◽  
Research Funding ◽  
Stromal Cell ◽  
Significant Degree ◽  
Human Bone ◽  
Hematopoietic Stem ◽  
High Degree

Abstract Understanding the regulation of normal and malignant human hematopoiesis requires a comprehensive cell atlas of the hematopoietic stem cell (HSC) regulatory microenvironment. Recent studies using scRNA-seq technologies have shed light on the organization of the hematopoietic regulatory microenvironment in the mouse. These studies have resolved some of the controversies regarding the overlap of stromal populations, the description of certain discrete stromal cells as professional, hematopoietic cytokine-producing populations, but also helped to delineate the relationship between specific stromal cell types in the murine BM. Nevertheless, these studies are limited by the number of cells sequenced, potentially hampering our ability to resolve the full spectrum of cellular states and differentiation stages that define the stromal BM microenvironment. Further, knowledge on the conservation of the cellular composition in the human BM stroma is in its infancy due to the difficulty of obtaining high-quality samples with sufficient stromal cell numbers from healthy individuals. This leaves us with two outstanding challenges; how to piece together such different fragments towards a comprehensive molecular atlas and to what extent such an atlas in mice is conserved in the human bone marrow. Here, we dissect the intrinsic organization and the heterogeneity within the endothelial (EC) and mesenchymal cell populations (MSC) governing the BM microenvironment in mouse and human. This was accomplished through customized bioinformatics integration of multiple scRNA-seq datasets along with the inclusion of over 50.000 murine and human bone marrow stromal cells. By these means, we were able to identify new subsets of MSC and EC, but more importantly, to define new molecular markers to identify highly specialized subpopulations of cells in the murine BM microenvironment. Pathway enrichment analysis unveiled multiple, potentially transient cell states defined by differential gene expression and the enrichment of specific functional characteristics. Importantly, 14 EC subsets were characterized by enrichment in pathways known to be essential for endothelial homeostasis maintenance, demonstrating a high degree of specialization in the endothelium. Similarly, 11 transient cell states in the MSC compartment were defined and characterized by their differentiation capacity. Importantly, our deep deconvolution of the heterogeneous mesenchymal and endothelial compartments became feasible only by integrating multiple datasets. Furthermore, based on the knowledge generated in the mouse, we were able to describe how much of the information and targets from the mouse can be of interest in human characterization. This analysis identified the expression of the human orthologs to the murine cluster-defining genes with different degrees of enrichment in the endothelium and mesenchyme. Moreover, some of these shared genes in mice and human stromal cells corresponded to the GO-defining genes of the different clusters identified in the mouse. These findings suggest a significant degree of conservation regarding the cellular states that define the stromal microenvironment in mouse and human. Although additional studies and improved processing of human samples will be required for deep characterization of the human BM microenvironment, these preliminary results validate our integrative cross-species approach. Taken together, our study provides a deeper understanding of the composition and specialization of the BM microenvironment and point towards a significant degree of conservation between species. Moreover, we demonstrate the usefulness of the multi-dataset integration and the customized clustering approach used in our study to improve the resolution of complex tissues and organs. This approach promises to aid in the construction of cell atlases by reducing the resources associated with sequencing that a single lab will need to invest in order to obtain meaningful depth in single-cell analysis. Future studies integrating genome, transcriptome, epigenome, proteome, and anatomical positioning together with functional assays to correlate descriptive phenotypes with functional data will help fully resolve the composition, regulation, and connectivity in the BM microenvironment in health and disease. Figure 1 Figure 1. Disclosures Paiva: Adaptive, Amgen, Bristol-Myers Squibb-Celgene, Janssen, Kite Pharma, Sanofi and Takeda: Honoraria; Bristol-Myers Squibb-Celgene, Janssen, and Sanofi: Consultancy; Celgene, EngMab, Roche, Sanofi, Takeda: Research Funding. Saez: Magenta Therapeutics: Patents & Royalties. Prosper: BMS-Celgene: Honoraria, Research Funding; Janssen: Honoraria; Oryzon: Honoraria.

A Zebrafish Model of Fetal Bone Marrow Provides a Dynamic View of Hematopoietic Stem Cell Niche Colonization

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 170-170
Author(s):  
Owen J Tamplin ◽  
Jonathan E Henninger ◽  
Hunter L Elliott ◽  
Douglas S Richardson ◽  
Leonard I. Zon
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Early Stage ◽  
Transgenic Zebrafish ◽  
Bone Marrow Niche ◽  
Hematopoietic Stem ◽  
Cell Pool ◽  
Equity Ownership ◽  
Stem Cell Pool

Abstract The entire blood system is supported throughout life by a small number of hematopoietic stem and progenitor cells (HSPCs) that are produced exclusively during embryonic development. These stem cells are generated from the hemogenic endothelium of the dorsal aorta, then migrate to the fetal liver where they expand, before making a final migration to the fetal bone marrow. After seeding the bone marrow, the stem cell pool stabilizes and the total number of HSPCs remains relatively constant. Very little is known about this early stage of bone marrow niche colonization. A better understanding of native stem cell pool establishment will likely lead to improved clinical HSPC transplantation that depends on repopulation of the bone marrow niche. Currently, imaging technology does not allow direct visualization of the bone marrow niche during colonization because it occurs in utero in the long bones of the fetus. The zebrafish is an advantageous model because the embryos develop externally and are transparent. To quantify the early stem cell pool, we employed long term fate mapping with clonal analysis using the multicolor Zebrabow system, which imparts a unique fluorescent hue to stem cells and their progeny. Our findings reveal that 21 HSPC clones exist prior to HSPC emergence (24 hours post fertilization) and 30 clones are present during peak production from the aorta (48 hours post fertilization). Seeding of the presumptive adult marrow niche in zebrafish begins 4-5 days post fertilization, versus 16.5 days in the mouse. We previously described a transgenic zebrafish line (Runx:mCherry) that marks long term repopulating HSPCs throughout development and into adulthood. HSPC-specific expression is driven by the well-characterized Runx1 +23 kb mouse enhancer element. We used this line to directly observe the earliest immigration events of HSPCs as they arrive in the marrow. To achieve this, we immobilized the zebrafish by injection of the snake venom protein alpha-bungarotoxin directly into circulation. This allowed long term live imaging of the niche (~16 hours) so we could quantify the dynamics of HSPC colonization and expansion. To rapidly acquire high resolution imaging data for this deep tissue we applied lightsheet microscopy. By simultaneously illuminating the sample in the X plane, while taking images in the Z plane, hundreds of optical sections can be captured in seconds. The high pixel and temporal resolution of lightsheet microscopy in a large volume of tissue provides a highly dynamic view of the entire marrow niche. We could assess the localization of HSPCs in relation to other cell types within the niche. For example, HSPCs were closely associated with endothelial cells in a perivascular niche, similar to what has been described in mammalian bone marrow. Furthermore, we could quantify single Runx+ nuclei over time on one side of the bilateral kidney marrow. During this early stage of niche colonization, we found the number of HSPCs per side was ~50 (so ~100 total) and that remained relatively constant. This was in fact a dynamic equilibrium achieved by ingress and egress of cells, as well as occasional cell divisions. This cell number was independently validated using another transgenic zebrafish line, cd41:GFP, that also marks HSPCs. This quantification, combined with our data from earlier development, suggests that HSPCs undergo around two population doublings between emergence from the aorta and engraftment in the marrow. This unique platform for the quantification of a total stem cell pool will allow further functional and mechanistic studies using both genetics and chemical biology. Our goal is to gain insights into the establishment of the stem cell pool within the niche microenvironment and how this could improve clinical transplantation outcomes. Disclosures Zon: Marauder Therapeutics: Equity Ownership, Other: Founder; Scholar Rock: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder; Fate, Inc.: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: Founder.

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