Spatial Analysis of Hematopoietic Stem and Progenitor Cells in the Bone Marrow

Abstract Sustained production of all mature blood cell types relies on the continuous proliferation and differentiation of a rare population of self-renewing, multipotent hematopoietic stem cells (HSCs). HSC maintenance and lineage differentiation are strictly regulated by distinct microenvironments, termed niches, defined by cellular components, soluble regulators, and by the extracellular matrix. Definitive identification of the location as well as cellular and extracellular characteristics of HSC niches in the bone marrow (BM) has not been completed due to limitations of conventional imaging techniques. We have employed a novel imaging technology, Laser Scanning Cytometry (LSC) to define the localization of hematopoietic stem and progenitor cells (HSPCs) within different regions of the BM. LSC allows imaging and objective quantitative analysis of the anatomical position(s), number, and frequency of specific cell populations within the native tissue microenvironment. Analysis of whole femoral longitudinal sections of Bmi-GFP mice, in which GFP is expressed at its highest levels in HSPCs, revealed that within the bone diaphysis, HSPCs (Bmi-GFPhi c-kit+) cells were highly enriched in endosteal regions (within 100nm away from inner bone surface) compared to the central medullary region. Importantly, our data show that HSPCs are found at highest frequencies in the metaphysis of long bones, suggesting that these areas, which display characteristic morphological features, are functionally distinct from the diaphyseal region and a preferential location for HSPC-specific niches. We are currently employing LSC to identify HSPC niche cellular constituents by quantifying the relative frequency at which these cells are found in association with previously proposed niche-components such as osteoblasts, BM endothelial sinusoidal cells and CXCL12-abundant reticular cells. A detailed understanding of niche-derived signals regulating unique properties of HSCs will certainly prove relevant in human HSPC transplantation and cell therapy.

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Zinc Finger Protein 521 Regulates Early Hematopoiesis through Cell-Extrinsic Mechanisms in the Bone Marrow Microenvironment

Molecular and Cellular Biology ◽

10.1128/mcb.00603-17 ◽

2018 ◽

Vol 38 (17) ◽

Cited By ~ 5

Author(s):

Courtney J. Fleenor ◽

Tessa Arends ◽

Hong Lei ◽

Josefine Åhsberg ◽

Kazuki Okuyama ◽

...

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Zinc Finger ◽

Zinc Finger Protein ◽

Cell Types ◽

Bone Marrow Microenvironment ◽

Cancer Therapies ◽

Hematopoietic Stem ◽

Finger Protein ◽

Stem And Progenitor Cells

ABSTRACTZinc finger protein 521 (ZFP521), a DNA-binding protein containing 30 Krüppel-like zinc fingers, has been implicated in the differentiation of multiple cell types, including hematopoietic stem and progenitor cells (HSPC) and B lymphocytes. Here, we report a novel role for ZFP521 in regulating the earliest stages of hematopoiesis and lymphoid cell development via a cell-extrinsic mechanism. Mice with inactivatedZfp521genes (Zfp521−/−) possess reduced frequencies and numbers of hematopoietic stem and progenitor cells, common lymphoid progenitors, and B and T cell precursors. Notably, ZFP521 deficiency changes bone marrow microenvironment cytokine levels and gene expression within resident HSPC, consistent with a skewing of hematopoiesis away from lymphopoiesis. These results advance our understanding of ZFP521's role in normal hematopoiesis, justifying further research to assess its potential as a target for cancer therapies.

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Hypoxic Hematopoietic Stem and Progenitor Cells Reside in Structurally Diverse Perivascular Niches in the Bone Marrow,

Blood ◽

10.1182/blood.v118.21.3417.3417 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3417-3417

Author(s):

Cesar Nombela-Arrieta ◽

Gregory Pivarnik ◽

Beatrice Winkel ◽

Brendan Harley ◽

John E Mahoney ◽

...

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Cell Biology ◽

Laser Scanning ◽

Conflicts Of Interest ◽

Quantitative Imaging ◽

Three Dimensional ◽

Global Distribution ◽

Hematopoietic Stem ◽

Stem And Progenitor Cells

Abstract Abstract 3417 The identification of specific microenvironments, in which Hematopoietic Stem and Progenitor Cells (HSPCs), reside within the BM is a major challenge in stem cell biology. Yet the extreme rarity of HSCs, their dynamic nature, and the lack of unique specific markers to identify them, have precluded an accurate definition of HSC niches to date. Using Laser Scanning Cytometry, a powerful emerging quantitative imaging technology that enables analysis of whole femoral sections at the single cell level, we have mapped the global distribution of hematopoietic stem and progenitor cells within femoral bone marrow cavities, and analyzed their inmediate surrounding microenvironment. Systematic mapping of the global distribution of endogenous HSPC-enriched populations in the BM, revealed an accumulation of these cells inside endosteal regions (ER <100μm from inner bone surface), but not necessarily in contact with endosteal surfaces. Interestingly, the vast majority of HSPCs were found in direct association with BM micrrovessels, further supporting previous work, which suggested bone marrow endothelium as a major component of HSPC niches. By employing a novel imaging approach, we provide a three-dimensional (3D) microscopic overview of the unique BM vascular network found in endosteal zones, which contain the transition of bone-lining arterioles and capillaries to the sinusoidal network. Of note, HSPC association to vascular structures is not restricted to sinusoids. A significant fraction of HSPCs lied adjacent to non-sinusoidal endothelium. Using five-color imaging cytometry and pimonidazole incorporation, we have assessed the hypoxic state of HSPCs in different BM microenvironments. Our in situ analysis reveals that intracellular hypoxia is a hallmark of HSPCs, independent of their distance to bone surfaces, and more importantly, regardless of their perivascular localization. These studies provide unequivocal anatomical evidence for the intrinsic rather than environmental regulation of intracellular hypoxia in HSPCs and challenge the hypothesis of a “super hypoxic” HSPC niche. Disclosures: No relevant conflicts of interest to declare.

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Bone Angiogenesis and Vascular Niche Remodeling in Stress, Aging, and Diseases

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.602269 ◽

2020 ◽

Vol 8 ◽

Author(s):

Sina Stucker ◽

Junyu Chen ◽

Fiona E. Watt ◽

Anjali P. Kusumbe

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Cell Types ◽

Stress Factors ◽

Hematopoietic Stem ◽

Perivascular Cell ◽

Vascular Niche ◽

Bm Niche ◽

Highly Sensitive ◽

Stem And Progenitor Cells

The bone marrow (BM) vascular niche microenvironments harbor stem and progenitor cells of various lineages. Bone angiogenesis is distinct and involves tissue-specific signals. The nurturing vascular niches in the BM are complex and heterogenous consisting of distinct vascular and perivascular cell types that provide crucial signals for the maintenance of stem and progenitor cells. Growing evidence suggests that the BM niche is highly sensitive to stress. Aging, inflammation and other stress factors induce changes in BM niche cells and their crosstalk with tissue cells leading to perturbed hematopoiesis, bone angiogenesis and bone formation. Defining vascular niche remodeling under stress conditions will improve our understanding of the BM vascular niche and its role in homeostasis and disease. Therefore, this review provides an overview of the current understanding of the BM vascular niches for hematopoietic stem cells and their malfunction during aging, bone loss diseases, arthritis and metastasis.

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A Meta-Analytic Single-Cell Atlas of Mouse Bone Marrow Hematopoietic Development

10.1101/2021.08.12.456098 ◽

2021 ◽

Author(s):

Benjamin D Harris ◽

John Lee ◽

Jesse Gillis

Keyword(s):

Bone Marrow ◽

Single Cell ◽

Progenitor Cells ◽

Cell Types ◽

Marker Genes ◽

Mouse Bone Marrow ◽

Clear Understanding ◽

Hematopoietic Stem ◽

Hematopoietic Development ◽

Stem And Progenitor Cells

The clinical importance of the hematopoietic system makes it one of the most heavily studied lineages in all of biology. A clear understanding of the cell types and functional programs during hematopoietic development is central to research in aging, cancer, and infectious diseases. Known cell types are traditionally identified by the expression of proteins on the surface of the cells. Stem and progenitor cells defined based on these markers are assigned functions based on their lineage potential. The rapid growth of single cell RNA sequencing technologies (scRNAseq) provides a new modality for evaluating the cellular and functional landscape of hematopoietic stem and progenitor cells. The popularity of this technology among hematopoiesis researchers enables us to conduct a robust meta-analysis of mouse bone marrow scRNAseq data. Using over 300,000 cells across 12 datasets, we evaluate the classification and function of cell types based on discrete clustering, in silico FACS sorting, and a continuous trajectory. We identify replicable signatures that define cell types based on genes and known cellular functions. Additionally, we evaluate the conservation of signatures associated with erythroid and monocyte lineage development across species using co-expression networks. The co-expression networks predict the effectiveness of the signature at identifying erythroid and monocyte cells in zebrafish and human scRNAseq data. Together, this analysis provides a robust reference, particularly marker genes and functional annotations, for future experiments in hematopoietic development.

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Faculty Opinions recommendation of Bone marrow CD169+ macrophages promote the retention of hematopoietic stem and progenitor cells in the mesenchymal stem cell niche.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.11493958.12528059 ◽

2011 ◽

Author(s):

Devendra Agrawal ◽

Vineet Agrawal

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

Mesenchymal Stem Cell ◽

Progenitor Cells ◽

Stem Cell Niche ◽

Hematopoietic Stem ◽

Stem And Progenitor Cells ◽

Cell Niche

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Mechanism of Action of Diallyl Sulphide in Ameliorating the Hematopoietic Radiation Injury

Journal of Health and Allied Sciences NU ◽

10.1055/s-0041-1730094 ◽

2021 ◽

Author(s):

Omika Katoch ◽

Mrinalini Tiwari ◽

Namita Kalra ◽

Paban K. Agrawala

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Progenitor Cells ◽

Hematopoietic Stem ◽

Proliferation And Differentiation ◽

Stem And Progenitor Cells ◽

Radiation Induced ◽

Medicinal Properties ◽

Marrow Cellularity

AbstractDiallyl sulphide (DAS), the pungent component of garlic, is known to have several medicinal properties and has recently been shown to have radiomitigative properties. The present study was performed to better understand its mode of action in rendering radiomitigation. Evaluation of the colonogenic ability of hematopoietic progenitor cells (HPCs) on methocult media, proliferation and differentiation of hematopoietic stem cells (HSCs), and transplantation of stem cells were performed. The supporting tissue of HSCs was also evaluated by examining the histology of bone marrow and in vitro colony-forming unit–fibroblast (CFU-F) count. Alterations in the levels of IL-5, IL-6 and COX-2 were studied as a function of radiation or DAS treatment. It was observed that an increase in proliferation and differentiation of hematopoietic stem and progenitor cells occurred by postirradiation DAS administration. It also resulted in increased circulating and bone marrow homing of transplanted stem cells. Enhancement in bone marrow cellularity, CFU-F count, and cytokine IL-5 level were also evident. All those actions of DAS that could possibly add to its radiomitigative potential and can be attributed to its HDAC inhibitory properties, as was observed by the reversal radiation induced increase in histone acetylation.

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