ABSTRACT: Location of indigenous human HSCs reveals functional properties of HSCs that are dictated by anatomic and cellular architecture of bone marrow
Project description:Location of indigenous human HSCs reveals functional properties of HSCs that are dictated by anatomic and cellular architecture of bone marrow II
Project description:Location of indigenous human HSCs reveals functional properties of HSCs that are dictated by anatomic and cellular architecture of bone marrow I
Project description:Demonstration of hematopoietic stem cells (HSCs) was first shown in the mouse and was dependent on recipient bone marrow (BM) to support in vivo multilineage hematopoietic reconstitution, thereby illustrating non-cell-autonomous requirements for HSC functions. Murine studies have defined microanatomic compartments in the BM comprised of osteoblasts, mesenchymal cells, subsets of vasculature, and innervating neural cells functioning as an HSC-supportive niche. Despite the potential clinical applications, analyses of putative HSCs in the BM of humans has not been examined. Here, using human bone biopsies, we provide evidence of HSC propensity to endosteal regions of Trabecular Bone Area (TBA). Independent of phenotypic definitions based on prospective isolation, functional studies indicate that human HSCs residing in the TBA of human and transplanted recipients had superior regenerative and self-renewal capacity and are molecularly distinct to those repopulating the Long Bone Area (LBA). Consistent with the non-cell-autonomous nature of HSC function, osteoblasts in the TBA possess unique characteristics and expressed a key network of factors including those involving Notch activity which could regulate TBA vs. LBA location of human HSCs in vivo. Our study illustrates that human-mouse xenografts provide a surrogate to indigenous human HSC in the BM, and demonstrates that BM architecture plays a critical role in defining functional properties of human HSCs. Total bone marrow cells were collected from NOD/SCID recipient adult mice. Osteoblast cells (OB) were sorted based on five paramater markers combination Lin- CD45- CD31- Sca1- CD51+ using a FACSAria II (BD). Total RNA from purified populations was extracted and amplified as described previously (Shojaei et al., 2005). Amplified-labeled RNA was hybridized to HG-U133Plus v2.0 chip.
Project description:Demonstration of hematopoietic stem cells (HSCs) was first shown in the mouse and was dependent on recipient bone marrow (BM) to support in vivo multilineage hematopoietic reconstitution, thereby illustrating non-cell-autonomous requirements for HSC functions. Murine studies have defined microanatomic compartments in the BM comprised of osteoblasts, mesenchymal cells, subsets of vasculature, and innervating neural cells functioning as an HSC-supportive niche. Despite the potential clinical applications, analyses of putative HSCs in the BM of humans has not been examined. Here, using human bone biopsies, we provide evidence of HSC propensity to endosteal regions of Trabecular Bone Area (TBA). Independent of phenotypic definitions based on prospective isolation, functional studies indicate that human HSCs residing in the TBA of human and transplanted recipients had superior regenerative and self-renewal capacity and are molecularly distinct to those repopulating the Long Bone Area (LBA). Consistent with the non-cell-autonomous nature of HSC function, osteoblasts in the TBA possess unique characteristics and expressed a key network of factors including those involving Notch activity which could regulate TBA vs. LBA location of human HSCs in vivo. Our study illustrates that human-mouse xenografts provide a surrogate to indigenous human HSC in the BM, and demonstrates that BM architecture plays a critical role in defining functional properties of human HSCs. Lin- MNCs from human Umbilical Cord blood (CB) were injected via tail vein into sublethally irradiated NOD/SCID adult mice. After 10 weeks post-transplantation, engrafted-CB cells were sorted based on the co-expression of CD45 and CD34, and absence or presence of CD38 using a FACSAria II (BD). Total RNA from purified populations was extracted and amplified as described previously (Shojaei et al., 2005). Amplified-labeled RNA was hybridized to HG-U133Plus v2.0 chip.
Project description:Demonstration of hematopoietic stem cells (HSCs) was first shown in the mouse and was dependent on recipient bone marrow (BM) to support in vivo multilineage hematopoietic reconstitution, thereby illustrating non-cell-autonomous requirements for HSC functions. Murine studies have defined microanatomic compartments in the BM comprised of osteoblasts, mesenchymal cells, subsets of vasculature, and innervating neural cells functioning as an HSC-supportive niche. Despite the potential clinical applications, analyses of putative HSCs in the BM of humans has not been examined. Here, using human bone biopsies, we provide evidence of HSC propensity to endosteal regions of Trabecular Bone Area (TBA). Independent of phenotypic definitions based on prospective isolation, functional studies indicate that human HSCs residing in the TBA of human and transplanted recipients had superior regenerative and self-renewal capacity and are molecularly distinct to those repopulating the Long Bone Area (LBA). Consistent with the non-cell-autonomous nature of HSC function, osteoblasts in the TBA possess unique characteristics and expressed a key network of factors including those involving Notch activity which could regulate TBA vs. LBA location of human HSCs in vivo. Our study illustrates that human-mouse xenografts provide a surrogate to indigenous human HSC in the BM, and demonstrates that BM architecture plays a critical role in defining functional properties of human HSCs.
Project description:Demonstration of hematopoietic stem cells (HSCs) was first shown in the mouse and was dependent on recipient bone marrow (BM) to support in vivo multilineage hematopoietic reconstitution, thereby illustrating non-cell-autonomous requirements for HSC functions. Murine studies have defined microanatomic compartments in the BM comprised of osteoblasts, mesenchymal cells, subsets of vasculature, and innervating neural cells functioning as an HSC-supportive niche. Despite the potential clinical applications, analyses of putative HSCs in the BM of humans has not been examined. Here, using human bone biopsies, we provide evidence of HSC propensity to endosteal regions of Trabecular Bone Area (TBA). Independent of phenotypic definitions based on prospective isolation, functional studies indicate that human HSCs residing in the TBA of human and transplanted recipients had superior regenerative and self-renewal capacity and are molecularly distinct to those repopulating the Long Bone Area (LBA). Consistent with the non-cell-autonomous nature of HSC function, osteoblasts in the TBA possess unique characteristics and expressed a key network of factors including those involving Notch activity which could regulate TBA vs. LBA location of human HSCs in vivo. Our study illustrates that human-mouse xenografts provide a surrogate to indigenous human HSC in the BM, and demonstrates that BM architecture plays a critical role in defining functional properties of human HSCs.
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the mechanisms by which ectopic Sox17 expression in adult hematopoietic progenitors increased self-renewal potential and conferred fetal HSC properties, we compared the gene expression profiles of E16.5 fetal liver HSCs, young adult bone marrow HSCs, young adult bone marrow CD48+LSK cells, and Sox17-expressing CD48+LSK cells isolated from mice that had been transplanted with MSCV-Sox17-infected bone marrow cells 12 weeks earlier. Total RNA (~5ng) was isolated from 3 independent, freshly isolated aliquots of 10,000 E16.5 fetal liver HSCs, 10,000 fetal liver CD48+LSK cells, 10,000 adult bone marrow HSCs, 10,000 adult bone marrow CD48+LSK cells, 10,000 Sox17-expressing CD48+LSK cells isolated from primary recipients 12 weeks after transplantation of MSCV-Sox17-infected bone marrow cells. Purified RNA was reverse transcribed and amplified using the WT-Ovation™ Pico RNA Amplification system (NuGEN Technologies) following the manufacturer’s instructions. Sense strand cDNA was generated using WT-Ovation™ Exon Module (NuGEN), then fragmented and labeled using the FL-Ovation™ cDNA Biotin Module V2 (NuGEN). 2.5µg of labeled cDNA were hybridized to Affymetrix Mouse Gene ST 1.0 microarrays.
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the mechanisms by which ectopic Sox17 expression in adult hematopoietic progenitors increased self-renewal potential and conferred fetal HSC properties, we compared the gene expression profiles of E16.5 fetal liver HSCs, young adult bone marrow HSCs, young adult bone marrow CD48+LSK cells, and Sox17-expressing CD48+LSK cells isolated from mice that had been transplanted with MSCV-Sox17-infected bone marrow cells 12 weeks earlier.
Project description:The vulnerability of bone marrow hematopoiesis to perturbations of cholesterol metabolism is well documented, while the underlying cellular and molecular mechanisms remain poorly understood. Here we reveal a distinct cholesterol metabolic signature of hematopoietic stem cells (HSCs) within the hematopoietic compartment.To identify the phenotype switching and function variation in BM LT-HSCs with HCD treatment, we performed RNA-seq of LT-HSCs from the bone marrow of mice with or without3-month HCD treatment.
Project description:Fate decisions of haematopoietic stem cells (HSCs) to self-renew or differentiate in response to various demands are finely tuned by specialized microenvironments called “niches” in the bone marrow. Recent studies suggest that arterioles and sinusoids accompanied with distinct stromal cells marked by nerve/glial antigen 2 (NG2) and leptin receptor (LepR), compose distinct niches regulating quiescence and proliferation of HSCs, respectively. However, it remains unknown how the distinct niche cells differentially regulate the HSC functions. Here we show that effects of cytokines regulating HSC functions are dependent on the producing cell sources. Deletion of chemokine C-X-C motif ligand 12 (CXCL12) in NG2-cre targeted cells, which exclusively overlap with Nestin-GFP (Nes-GFP)+ stromal cells associated with arterioles and sinusoids, resulted in a robust reductions of HSCs in the bone marrow and massive mobilization. Deletion of CXCL12 from arteriolar NG2+ vascular smooth muscle cells caused a significant decrease of HSCs and altered HSC location in the marrow, while CXCL12 depletion from sinusoidal LepR+ cells did not reduce HSC numbers in the bone marrow. By contrast, deletion of stem cell factor (SCF) in LepR+ cells led to significant reductions in HSC numbers whereas SCF deletion in arteriolar NG2+ cells showed no effect on HSC numbers in the marrow. These results uncover the distinct contributions of cytokines derived from perivascular cells in separate vascular niches for HSC maintenance and mobilization. We sought to obtain comprehensive understanding of differences between peri-arteriolar and peri-sinusoidal niche cells by the present RNA-seq analysis.