Project description:Studies of adult human hematopoiesis have until now relied on the expression of CD10 to define lymphoid commitment. We report a novel lymphoid-primed population in human bone marrow that is generated from hematopoietic stem cells (HSC) prior to the onset of CD10 expression and B cell commitment, and is identified by high levels of the homing molecule L-selectin (CD62L). CD10-CD62Lhi progenitors have full lymphoid (B/T/NK) potential, and show reduced myeloid and absent erythroid potential. Genome-wide gene expression analysis demonstrates that the CD10-CD62Lhi population represents an intermediate stage of differentiation between CD34+CD38- HSC and CD34+lin-CD10+ progenitors marked by down-regulation of TAL1 and MPL, upregulation of E2A, CD3E and IL2RG expression, and absent B cell commitment or RAG1/2 expression. Immature CD34+CD1a- thymocytes are also CD62Lhi and L-selectin ligands are expressed at the cortico-medullary junction, suggesting a possible role for L-selectin in human thymic homing. These studies identify the earliest stage of lymphoid priming in human bone marrow. Freshly harvested human bone marrow was ficoll purified, enriched for CD34+, and then FACS sorted. It was then sorted into 3 samples CD34+CD38-, CD34+ CD10- CD62L++, and CD34+ CD10+, with 3 independent biological replicates
Project description:Studies of adult human hematopoiesis have until now relied on the expression of CD10 to define lymphoid commitment. We report a novel lymphoid-primed population in human bone marrow that is generated from hematopoietic stem cells (HSC) prior to the onset of CD10 expression and B cell commitment, and is identified by high levels of the homing molecule L-selectin (CD62L). CD10-CD62Lhi progenitors have full lymphoid (B/T/NK) potential, and show reduced myeloid and absent erythroid potential. Genome-wide gene expression analysis demonstrates that the CD10-CD62Lhi population represents an intermediate stage of differentiation between CD34+CD38- HSC and CD34+lin-CD10+ progenitors marked by down-regulation of TAL1 and MPL, upregulation of E2A, CD3E and IL2RG expression, and absent B cell commitment or RAG1/2 expression. Immature CD34+CD1a- thymocytes are also CD62Lhi and L-selectin ligands are expressed at the cortico-medullary junction, suggesting a possible role for L-selectin in human thymic homing. These studies identify the earliest stage of lymphoid priming in human bone marrow.
Project description:Lymphoid committed CD34+lin-CD10+CD24- progenitors undergo a rebound at month 3 after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the absence of acute graft-versus-host disease (aGVHD). Here, we analyzed transcriptional programs of cell-sorted circulating lymphoid committed progenitors and CD34+Lin-CD10- non lymphoid progenitors in 11 allo-HSCT patients having (n=5) or not developed (n=6) grade 2 or 3 aGVHD and in 7 age-matched healthy donors. Major deregulated pathways included protein synthesis, energy production, cell cycle regulation and cytoskeleton organization. Notably, genes from protein biogenesis, translation machinery and cell cycle (CDK6) were over-expressed in progenitors from patients in the absence of aGVHD compared with healthy donors and patients affected by aGVHD. Expression of many genes from the mitochondrial oxidative phosphorylation metabolic pathway leading to ATP production were more specifically increased in lymphoid committed progenitors in absence of aGVHD. This was also the case for genes involved in cell mobilization such as those regulating Rho GTPases activity. In all, we show that circulating lymphoid committed progenitors undergo profound changes in metabolism favoring cell proliferation, energy production and cell mobilization after allo-HSCT in humans. These mechanisms are abolished in case of aGVHD or its treatment, indicating a persistent cell-intrinsic defect after exit from bone marrow.
Project description:Human lymphopoiesis is a dynamic life-long process that starts in utero at 6 weeks gestation; however developmental pathways defining fetal lymphopoiesis are largely unexplored. While the first committed B-progenitor in normal human bone marrow (BM) is a CD10+ve ProB-progenitor, the identification of a CD10-ve B-progenitor (Pre/ProB progenitor) in cord blood suggests there may be a second B-lymphoid development program in fetal life. Here, we provide a comprehensive analysis of the fetal B-cell developmental hierarchy and report the presence of both PreProB- and ProB-progenitors in fetal tissues and describe their ontogeny, molecular and functional characteristics. PreProB- and ProB-progenitors appear early in the first trimester in fetal liver, followed by a sustained second wave of B-progenitor development in fetal BM, where together they form >40% of the total HSC/progenitor pool. Unexpectedly, one-third of the B-progenitors (13±1% of lin-CD34+ cells) are CD10-ve PreProB-progenitors while, by contrast, PreProB-progenitors are virtually undetectable in adult BM. Single-cell transcriptomics and functional assays place PreProB- upstream of ProB-progenitors, identifying them as the first B-lymphoid restricted progenitor in human fetal life. Fetal BM PreProB- and ProB-progenitors both give rise solely to B-lineage cells yet they are transcriptionally distinct. PreProB- unlike ProB-progenitors, continue to express a number of key myeloid and stem cell genes and share some transcriptomic signatures with CD10-ve B-progenitor infant acute lymphoblastic leukemia blast cells. Our data identify PreProB-progenitors as the earliest B-lymphoid restricted progenitor in human fetal life, and suggest that this fetal-restricted committed B-progenitor might provide a permissive cellular context for prenatal B-progenitor leukemia initiation.
Project description:Human lymphopoiesis is a dynamic life-long process that starts in utero at 6 weeks gestation; however developmental pathways defining fetal lymphopoiesis are largely unexplored. While the first committed B-progenitor in normal human bone marrow (BM) is a CD10+ve ProB-progenitor, the identification of a CD10-ve B-progenitor (Pre/ProB progenitor) in cord blood suggests there may be a second B-lymphoid development program in fetal life. Here, we provide a comprehensive analysis of the fetal B-cell developmental hierarchy and report the presence of both PreProB- and ProB-progenitors in fetal tissues and describe their ontogeny, molecular and functional characteristics. PreProB- and ProB-progenitors appear early in the first trimester in fetal liver, followed by a sustained second wave of B-progenitor development in fetal BM, where together they form >40% of the total HSC/progenitor pool. Unexpectedly, one-third of the B-progenitors (13±1% of lin-CD34+ cells) are CD10-ve PreProB-progenitors while, by contrast, PreProB-progenitors are virtually undetectable in adult BM. Single-cell transcriptomics and functional assays place PreProB- upstream of ProB-progenitors, identifying them as the first B-lymphoid restricted progenitor in human fetal life. Fetal BM PreProB- and ProB-progenitors both give rise solely to B-lineage cells yet they are transcriptionally distinct. PreProB- unlike ProB-progenitors, continue to express a number of key myeloid and stem cell genes and share some transcriptomic signatures with CD10-ve B-progenitor infant acute lymphoblastic leukemia blast cells. Our data identify PreProB-progenitors as the earliest B-lymphoid restricted progenitor in human fetal life, and suggest that this fetal-restricted committed B-progenitor might provide a permissive cellular context for prenatal B-progenitor leukemia initiation.
Project description:Comparison of gene expression profiling analysis of bone marrow isolated CD34+ cells from patients with MALT lymphoma vs. healthy individuals revealed a large number of differentially expressed genes that included NF-kB target genes, genes involved in inflamatory signalling and immunoglobulin genes, suggesting an early lymphoid B-cell priming. Chromosomal translocations involving MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. However, targeting these translocations to mouse B-cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1+Lin- hematopoietic stem/progenitor cells (HS/PCs), leading to the development of tumors recapitulating the clinical, histopathological and molecular features of human MALT lymphomas. Ablation of the p53 gene induced transformation of MALT lymphoma to diffuse large-cell lymphoma of activated B-cell type (ABC-DLBCL). Human CD34+ cells isolated from MALT lymphoma patients displayed an abnormal transcriptional program that was shared by MALT lymphoma cells, transgenic mouse Sca1+Lin- cells and Sca1-MALT1-induced lymphomas. Our study shows that MALT lymphoma can be modeled in mice by targeting MALT1 oncogene to HS/PCs. 10 samples were analyzed of which 5 are CD34+ cells sorted from the bone marrow of MALT patients and are compared to the other 5 CD34+ cells sorted from the bone marrow of healthy donors.
Project description:Second dataset release from the Immunological Proteome Resource (ImmPRes). This dataset contains both lymphoid and myeloid populations. The whole list is as follows: Bone marrow derived eosinophils, bone marrow derived mast cells, bone marrow derived macrophages, NK cells, TH2 cells, TH17 cells, Cytotoxic T cells cultured in IL15 and Naive CD8+ T cells extractred from the lymph nodes of C57BL/6J mice.
Project description:During aging, hematopoietic stem cell (HSC) function progressively declines which can lead to reduced blood cell production and regeneration, impaired lymphoid cell production and ineffective erythropoiesis. In this study, we uncovered that during aging the cell surface presentation of the type-1 transmembrane protein P-selectin (CD62P, encoded by Selp) increases in a large fraction of HSCs. Notably, expression of P-selectin molecularly and functionally dichotomized the aging HSC pool; stem cells presenting with high abundance of P-selectin were hallmarked by aging-associated gene expression programs and reduced repopulation upon regenerative stress. Overexpression of Selp in young HSCs was sufficient to impair long-term reconstitution potential and repress erythropoiesis. Moreover, IL-1β, which is chronically elevated in the aged bone marrow, triggered Selp expression in HSCs. The aged transcriptome, including Selp, was largely restored when aged HSCs were transplanted to young mice. Mechanistically, we uncovered that appropriate stimulation of P-selectin by its primary ligand, P-selectin glycoprotein ligand-1 (PSGL-1), suppressed aging-associated gene expression and reversely, lack of P-selectin signaling led to HSC premature aging. Collectively, our study uncovered a novel functional role of P-selectin engagement in regulating HSC regeneration and driving stem cell aging when perturbed.
Project description:MyD88-independent signal transduction associated with Toll-like receptors (TLRs) 3 and TLR4 is mediated through the adapter protein TRIF (TIR-domain-containing adapter-inducing interferon-beta). It has been proposed that TLR signalling is important for the transcription of crucial inflammasome components like NLRP3, a process that has been termed "priming". In order to test whether TRIF signalling was required for the priming of inflammasome components, we performed a genome wide transcriptional analysis on wild-type and Trif-knockout bone marrow derived macrophages (BMMs) before and 1, 3 and 6 hours after phagocytosis of E. coli. These results indicated that TRIF was involved in the activation and not transcriptional priming of the NLRP3 inflammasome. Bone marrow derived macrophages from WT and Trif knockout mice, stimulated with E.coli for up to 6hrs.
Project description:The purpose of the study was to determine whether priming with poly(I:C) altered the protein content of extracellular vesicles (EVs) released from bone marrow-derived MSCs and whether priming with hydrogen peroxide altered the protein content of EVs from adipose-derived MSCs