Fibroblastic colony-forming unit bone marrow cells delay progression to gastric dysplasia in a helicobacter model of gastric tumorigenesis.
ABSTRACT: Bone marrow mesenchymal stem cells (MSCs) have been shown to have immune modulatory effects. Despite efforts to identify these cells in vivo, to date, MSCs have been defined mainly by their in vitro cell characteristics. Here, we show that Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells make up approximately 0.5%-1% of murine whole bone marrow cells and yield nearly an equal amount of fibroblastic colony-forming units (CFU-F) as whole bone marrow. After transplantation into lethally irradiated recipients, Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells engrafted in the bone marrow long-term and demonstrated characteristics of MSCs, including capacity to differentiate into osteoblasts and adipocytes. To examine whether Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells have immune modulatory effects, in vitro coculture with activated CD4+ T-cells resulted in decreased Th17 cell differentiation by Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells. Furthermore, serial infusions with Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells reduced the progression to low-grade gastric dysplasia in mice infected with chronic Helicobacter felis (p = .038). This correlated with reduced gastric interleukin (IL)-17F, IL-22, and ROR-gammat gene expression in responding mice (p < .05). These data suggest that bone marrow derived Lin(-)CD44(hi)Sca1(-)cKit+CD34(-) cells have characteristics of MSCs and reduce progression of early gastric tumorigenesis induced by chronic H. felis infection. The prevention of dysplastic changes may occur through inhibition of Th17-dependent pathways.
Project description:Blood is a tissue with a high cell turnover rate that is constantly being replenished by bone marrow hematopoietic stem cells (HSCs) seeded during fetal ontogeny from the liver. Here we show that the long-term (LT) reconstituting subset of cKit(+)Thy1.1(lo)Lin(-/lo)Sca1(+)Flk2(-) HSCs is CD150(+). HSCs sourced from the fetal liver show LT, multilineage engraftment from E14.5 onward, and the CD150 cell surface molecule can readily substitute Thy1.1 as a positive marker of LT-HSCs in this tissue. From both fetal liver and adult bone marrow, cKit(+)Thy1.1(lo)Lin(-/lo)Sca1(+)Flk2(-) CD150(+) cells exhibit robust LT competitive engraftment, self-renewal, multilineage differentiation capacity, and an accessible chromatin configuration consistent with high expression of erythroid/megakaryoid genes in purified cell subsets. Our data show that, with appropriate combinations of cell surface markers, stem cells can be accurately isolated to high purity and characterized. This is important for the clarification of lineage relationships and the identification of bona fide regulators of stem cell self-renewal and differentiation both in normal and neoplastic tissues.
Project description:E-proteins are widely expressed basic helix-loop-helix (HLH) transcription factors that regulate differentiation in many cell lineages, including lymphoid, muscle, and neuronal cells. E-protein function is controlled by HLH inhibitors such as Id and SCL/TAL1 proteins, which recently have been suggested to play a role in hematopoietic stem cell (HSC) differentiation. However, the precise stages when these proteins are expressed and their specific functions are not entirely clear. Using a knock-in mouse model where the sequence for the enhanced green fluorescent protein (GFP) was inserted downstream of the Id1 promoter, we were able to track Id1 expression on an individual cell basis and detected Id1 expression in long-term repopulating HSCs (LT-HSCs). Functional assays showed that the Id1/GFP(+)Lin(-)Sca1(+)c-kit(Hi) population was highly enriched for LT-HSCs. Consistent with this expression pattern, Id1 deficiency led to a 2-fold reduction in the number of LT-HSCs defined as Lin(-)Sca1(+)c-kit(Hi)CD48(-)CD150(+). Primary bone marrow transplantation studies revealed that Id1 is dispensable for short-term engraftment. In contrast, both Id1(-/-) whole bone marrow and Lin(-)Sca1(+)c-kit(Hi)Thy1.1(Lo)-enriched HSCs, but not Id3(-/-) marrow, displayed impaired engraftment relative to wild-type controls in secondary transplantation assays. These findings suggest a unique role for Id1 in LT-HSC maintenance and hematopoietic development.
Project description:Hematopoietic progenitor cells are the progeny of hematopoietic stem cells that coordinate the production of precise numbers of mature blood cells of diverse functional lineages. Identification of cell-surface antigen expression associated with hematopoietic lineage restriction has allowed prospective isolation of progenitor cells with defined hematopoietic potential. To clarify further the cellular origins of megakaryocyte commitment, we assessed the in vitro and in vivo megakaryocyte and platelet potential of defined progenitor populations in the adult mouse bone marrow. We show that megakaryocytes arise from CD150(+) bipotential progenitors that display both platelet- and erythrocyte-producing potential in vivo and that can develop from the Flt3(-) fraction of the pregranulocyte-macrophage population. We define a bipotential erythroid-megakaryocyte progenitor population, the CD150(+)CD9(lo)endoglin(lo) fraction of Lin(-)cKit(+)IL7 receptor alpha(-)Fc?RII/III(lo)Sca1(-) cells, which contains the bulk of the megakaryocyte colony-forming capacity of the bone marrow, including bipotential megakaryocyte-erythroid colony-forming capacity, and can generate both erythrocytes and platelets efficiently in vivo. This fraction is distinct from the CD150(+)CD9(hi)endoglin(lo) fraction, which contains bipotential precursors with characteristics of increased megakaryocytic maturation, and the CD150(+)CD9(lo)endoglin(hi) fraction, which contains erythroid lineage-committed cells. Finally, we demonstrate that bipotential erythroid-megakaryocyte progenitor and CD150(+)CD9(hi)endoglin(lo) cells are TPO-responsive and that the latter population specifically expands in the recovery from thrombocytopenia induced by anti-platelet serum.
Project description:Agilent chip was used to measure microRNA expression in the Lin- cKit+ Sca1+ bone marrow compartment and in total bone marrow. Overall design: RNA was isolated by miRNeasy (Qiagen) from 1) Lin-cKit+Sca1+ cells, isolated from bone marrow using MACS column purification followed by fluorescent cell sorting, and 2) total Bone Marrow. Agilent microRNA microarray was run on these two samples.
Project description:Mast cells are rare tissue-resident immune cells that are involved in allergic reactions, and their numbers are increased in the lungs of asthmatics. Murine lung mast cells arise from committed bone marrow-derived progenitors that enter the blood circulation, migrate through the pulmonary endothelium, and mature in the tissue. In humans, mast cells can be cultured from multipotent CD34(+) progenitor cells. However, a population of distinct precursor cells that give rise to mast cells has remained undiscovered. To our knowledge, this is the first report of human lineage-negative (Lin(-)) CD34(hi) CD117(int/hi) Fc?RI(+) progenitor cells, which represented only 0.0053% of the isolated blood cells in healthy individuals. These cells expressed integrin ?7 and developed a mast cell-like phenotype, although with a slow cell division capacity in vitro. Isolated Lin(-) CD34(hi) CD117(int/hi) Fc?RI(+) blood cells had an immature mast cell-like appearance and expressed high levels of many mast cell-related genes as compared with human blood basophils in whole-transcriptome microarray analyses. Furthermore, serglycin, tryptase, and carboxypeptidase A messenger RNA transcripts were detected by quantitative reverse transcription-polymerase chain reaction. Altogether, we propose that the Lin(-) CD34(hi) CD117(int/hi) Fc?RI(+) blood cells are closely related to human tissue mast cells and likely constitute an immediate precursor population, which can give rise to predominantly mast cells. Furthermore, asthmatics with reduced lung function had a higher frequency of Lin(-) CD34(hi) CD117(int/hi) Fc?RI(+) blood mast cell progenitors than asthmatics with normal lung function.
Project description:Agilent chip was used to measure microRNA expression in the Lin- cKit+ Sca1+ bone marrow compartment and in total bone marrow. RNA was isolated by miRNeasy (Qiagen) from 1) Lin-cKit+Sca1+ cells, isolated from bone marrow using MACS column purification followed by fluorescent cell sorting, and 2) total Bone Marrow. Agilent microRNA microarray was run on these two samples.
Project description:BCR-ABL tyrosine kinase inhibitors (TKIs) are effective against chronic myeloid leukemia (CML), but they rarely eliminate CML stem cells. Disease relapse is common upon therapy cessation, even in patients with complete molecular responses. Furthermore, once CML progresses to blast crisis (BC), treatment outcomes are dismal. We hypothesized that concomitant targeting of BCL-2 and BCR-ABL tyrosine kinase could overcome these limitations. We demonstrate increased BCL-2 expression at the protein level in bone marrow cells, particularly in Lin(-)Sca-1(+)cKit(+) cells of inducible CML in mice, as determined by CyTOF mass cytometry. Further, selective inhibition of BCL-2, aided by TKI-mediated MCL-1 and BCL-XL inhibition, markedly decreased leukemic Lin(-)Sca-1(+)cKit(+) cell numbers and long-term stem cell frequency and prolonged survival in a murine CML model. Additionally, this combination effectively eradicated CD34(+)CD38(-), CD34(+)CD38(+), and quiescent stem/progenitor CD34(+) cells from BC CML patient samples. Our results suggest that BCL-2 is a key survival factor for CML stem/progenitor cells and that combined inhibition of BCL-2 and BCR-ABL tyrosine kinase has the potential to significantly improve depth of response and cure rates of chronic-phase and BC CML.
Project description:Nonhematopoietic bone marrow mesenchymal stem cells (BM-MSCs) are of central importance for bone marrow stroma and the hematopoietic environment. However, the exact phenotype and anatomical distribution of specified MSC populations in the marrow are unknown. We characterized the phenotype of primary human BM-MSCs and found that all assayable colony-forming units-fibroblast (CFU-Fs) were highly and exclusively enriched not only in the lin?/CD271?/CD45?/CD146? stem-cell fraction, but also in lin?/CD271?/CD45?/CD146(?/low) cells. Both populations, regardless of CD146 expression, shared a similar phenotype and genotype, gave rise to typical cultured stromal cells, and formed bone and hematopoietic stroma in vivo. Interestingly, CD146 was up-regulated in normoxia and down-regulated in hypoxia. This was correlated with in situ localization differences, with CD146 coexpressing reticular cells located in perivascular regions, whereas bone-lining MSCs expressed CD271 alone. In both regions, CD34? hematopoietic stem/progenitor cells were located in close proximity to MSCs. These novel findings show that the expression of CD146 differentiates between perivascular versus endosteal localization of non-hematopoietic BM-MSC populations, which may be useful for the study of the hematopoietic environment.
Project description:To identify the molecular characterisitics of parallel lineage-biased MPP populations arising from hematopoietic stem cells (HSC) we conducted genome-wide analyses of hematopoietic stem, progenitor and mature myeloid cell populations using Affymetrix Gene ST1.0 arrays. Microarray analysis of 3-5 biological replicates of the indicated hematopoietic populations, isolated by FACS sorting from C57BL/6 mouse BM. Immunophenotypic definitions: Long-term HSC (HSCLT) (Lin-/cKit+/Sca1+/Flk2-/CD48-/CD150+); Short-term HSC (HSCST) (Lin-/cKit+/Sca1+/Flk2-/CD48-/CD150-); MPP2 (Lin-/cKit+/Sca1+/Flk2-/CD48+/CD150+); MPP3 (Lin-/cKit+/Sca1+/Flk2-/CD48+/CD150-); MPP4 (Lin-/cKit+/Sca1+/Flk2+); CMP (Lin-/cKit+/FcγR-/CD34+); GMP (Lin-/cKit+/FcγR+/CD34+); Pre-granulocyte (PreGr) (Mac1+/Gr1int); Granulocyte (Gr) (Mac1+/Gr1hi). HSC and GMP samples listed here were also used as controls for our related microarray study GSE48893.
Project description:How inflammatory responses are mechanistically modulated by nicotinic acetylcholine receptors (nAChR), especially by receptors composed of alpha7 (?7) subunits, is poorly defined. This includes a precise definition of cells that express ?7 and how these impact on innate inflammatory responses. To this aim we used mice generated through homologous recombination that express an Ires-Cre-recombinase bi-cistronic extension of the endogenous ?7 gene that when crossed with a reporter mouse expressing Rosa26-LoxP (yellow fluorescent protein (YFP)) marks in the offspring those cells of the ?7 cell lineage (?7(lin+)). In the adult, on average 20-25 percent of the total CD45(+) myeloid and lymphoid cells of the bone marrow (BM), blood, spleen, lymph nodes, and Peyers patches are ?7(lin+), although variability between litter mates in this value is observed. This hematopoietic ?7(lin+) subpopulation is also found in Sca1(+)cKit(+) BM cells suggesting the ?7 lineage is established early during hematopoiesis and the ratio remains stable in the individual thereafter as measured for at least 18 months. Both ?7(lin+) and ?7(lin-) BM cells can reconstitute the immune system of naïve irradiated recipient mice and the ?7(lin+):?7(lin-) beginning ratio is stable in the recipient after reconstitution. Functionally the ?7(lin+):?7(lin-) lineages differ in response to LPS challenge. Most notable is the response to LPS as demonstrated by an enhanced production of IL-12/23(p40) by the ?7(lin+) cells. These studies demonstrate that ?7(lin+) identifies a novel subpopulation of bone marrow cells that include hematopoietic progenitor cells that can re-populate an animal's inflammatory/immune system. These findings suggest that ?7 exhibits a pleiotropic role in the hematopoietic system that includes both the direct modulation of pro-inflammatory cell composition and later in the adult the role of modulating pro-inflammatory responses that would impact upon an individual's lifelong response to inflammation and infection.