Project description:Self-renewing tissue-resident macrophages are thought to be exclusively derived from embryonic progenitors. However, whether circulating monocytes can also give rise to such macrophages has not been formally investigated. Here we use a new model of diphtheria toxin-mediated depletion of liver-resident Kupffer cells to generate niche availability and show that circulating monocytes engrafted in the liver, gradually adopt the transcriptional profile of their depleted counterparts and become long-lived self-renewing cells. Underlining the physiological relevance of our findings, circulating monocytes also contribute to the expanding pool of macrophages in the liver shortly after birth, when macrophage niches become available during normal organ growth. Thus, like embryonic precursors, monocytes can and do give rise to self-renewing tissue-resident macrophages if the niche is available to them. Clec4F+ Kupffer cells were isolated and sorted from livers from adult WT mice or KC-DTR or KC-DTR littermate control mice +/- 50ng DT at indicated timepoints. 19 samples (arrays) in total. RNA was isolated, amplified with Nugene pico kit, converted to cDNA and then hybridised on Affymetrix GeneChip Mouse Gene 1.0 ST Arrays.
Project description:Self-renewing tissue-resident macrophages are thought to be exclusively derived from embryonic progenitors. However, whether circulating monocytes can also give rise to such macrophages has not been formally investigated. Here we use a new model of diphtheria toxin-mediated depletion of liver-resident Kupffer cells to generate niche availability and show that circulating monocytes engrafted in the liver, gradually adopt the transcriptional profile of their depleted counterparts and become long-lived self-renewing cells. Underlining the physiological relevance of our findings, circulating monocytes also contribute to the expanding pool of macrophages in the liver shortly after birth, when macrophage niches become available during normal organ growth. Thus, like embryonic precursors, monocytes can and do give rise to self-renewing tissue-resident macrophages if the niche is available to them.
Project description:Tissue macrophages derive from bone marrow monocytes, and recent studies using mice have revealed that they also derive from yolk sac precursors or fetal liver monocytes. However, embryo-derived macrophages are supposed to be more important to maintain tissue macrophage pool because they can self-renew. Here, we show that adult bone marrow-derived macrophages (MDM) also retain the ability of self-renewal. Where they were readily obtained by a long-term culture: mouse bone marrow cells were cultured with macrophage colony-stimulating factor (M-CSF). After several passages, most MDM died owing to their limited life span with survival and expansion of self-renewing macrophages resided in a small fraction. Self-renewing macrophages were not tumorigenic, but proliferate for a long period in almost unlimited numbers. Despite being distinct from MDM, they were phenotypically and functionally differentiated macrophages, and could differentiate into dendritic cells or osteoclasts. Moreover, Krüppel-like Factor 2 (KLF2) involved in self-renewal of embryonic stem cells, was markedly up-regulated by M-CSF-stimulation in self-renewing macrophages, which was accompanied with a gradual down-regulation of MafB, a suppressor of KLF2 expression. Importantly, knockdown of KLF2 as well as c-Myc caused cell cycle arrest, apoptosis, and diminished cell growth. Our culture method results suggest the presence of precursor(s) for self-renewing macrophages in adult bone marrow that can be used to describe discrepancy of adult- and embryo-derived macrophages. Microarray data from both monocyte-derived and bone marrow-derived mouse macrophages are used to detail the global gene expression profile underlying phenotype, function and self-renewal capacity in order to unravel difference/similarity in phenotype/function and mechanism/degree of self-renewal between the two distinct macrophages.
Project description:Hematopoietic stem cells give rise to all blood lineages, can fully re-populate the bone marrow, and easily outlive the host organism. To better understand how stem cells remain fit during aging, we analyzed the proteome of hematopoietic stem and progenitor cells.
Project description:Tissue-resident macrophages can derive from yolk sac macrophages, fetal liver monocytes or adult bone marrow monocytes. Whether these precursors can give rise to transcriptionally identical alveolar macrophages is unknown. Here, we transferred traceable yolk sac macrophages, fetal liver monocytes, adult bone marrow monocytes or adult alveolar macrophages as a control, into the empty alveolar macrophage niche of neonatal Csf2rb-/- mice. All precursors efficiently colonized the alveolar niche and generated alveolar macrophages that were transcriptionally almost identical, with only 22 genes that could be linked to their origin. Underlining the physiological relevance of our findings, all transfer-derived alveolar macrophages self-maintained within the lungs for up to 1 year and durably prevented alveolar proteinosis. Thus, precursor origin does not affect the development of functional self-maintaining tissue-resident macrophages.
Project description:Tissue-resident macrophages can derive from yolk sac macrophages, fetal liver monocytes or adult bone marrow monocytes. Whether these precursors can give rise to transcriptionally identical alveolar macrophages is unknown. Here, we transferred traceable yolk sac macrophages, fetal liver monocytes, adult bone marrow monocytes or adult alveolar macrophages as a control, into the empty alveolar macrophage niche of neonatal Csf2rb-/- mice. All precursors efficiently colonized the alveolar niche and generated alveolar macrophages that were transcriptionally almost identical, with only 22 genes that could be linked to their origin. Underlining the physiological relevance of our findings, all transfer-derived alveolar macrophages self-maintained within the lungs for up to 1 year and durably prevented alveolar proteinosis. Thus, precursor origin does not affect the development of functional self-maintaining tissue-resident macrophages. CD45.1+CD45.2+ yolk sac macrophages, fetal liver monocytes, adult bone marrow monocytes or adult alveolar macrophages from the bronchoalveolar lavage were sorted from wild type CD45.1+CD45.2+ mice of indicated ages. From part of these samples RNA was isolated. The other part was transferred intranasally into the lungs of neonate Csf2rb-/- mice. 6 weeks post-transfer, transfer-derived CD45.1+CD45.2+ alveolar macrophages were sorted from the bronchoalveolar lavage. Wild type CD45.1+CD45.2 alveolar macrophages from the bronchoalveolar lavage of 6 week old mice were sorted as control. 36 samples (arrays) in total. RNA was isolated, amplified with Nugene pico kit, converted to cDNA and then hybridised on Affymetrix GeneChip Mouse Gene 1.0 ST Arrays.
Project description:Hematopoietic stem cells (HSC) has unique characteristic to self-renew and replenish the entire blood system. During development, HSCs originate in the aorta-gonads-mesonephros (AGM), from where they migrate into the fetal liver at E11. Once resided in fetal liver HSC proliferate extensively to make sufficient stem pool for adult life. Around birth, HSC from FL migrate to bone marrow (BM) which is major site of hematopoiesis for whole adult life. In contrast to FL HSC, BM HSC remain quiescence state and give rise to different blood cell type under normal homeostatic condition. It has shown that FL HSCs display significantly faster expansion kinetics when transplanted into lethally irradiate mice, compared with HSCs from adult BM. However, detail molecular mechanism behind the difference in self-renewal potential is not fully understood. Here, we present the genome-wide transcriptome analysis of more proliferative FL HSC compared to quiescent BM HSC using RNA-Seq platform.
Project description:Hematopoietic stem and progenitor cells are a rare, self-renewing bone marrow resident population capable of giving rise to all circulating hematopoietic cells. They can be used therapuetically for reconstituting defective or ablated hematopoietic systems following chemotherapy, and for inducing tolerance toward allografts of the same haplotype as the HSC donor. There are several sources for HSCs, such as the adult bone marrow, or umblical cord blood, which is more replete with such HSCs. However, HSCs obtained from such sources may be immunogenic, especially if isolated from adult bone marrow. To overcome this issue, our lab has establsihed human induced pluripotent stem cell-derived HPCs with the hope of creating a nonimmunogenic, readily available and unlimited source of HSCs to use for therapy. The goal of this study was to compare the gene expression profiles of naturally found HSCs (UCB-CD34+ HSCs) and HPCs differentiated from 4 different human iPS cell lines (iPS-HPCs), so as to determine the variation between the four iPS-HPCs and whether there were any differences between these HPCs and naturally found HSCs.
Project description:A critical problem in biology is understanding how cells choose between self-renewal and differentiation. To generate a comprehensive view of the mechanisms controlling early hematopoietic precursor self-renewal and differentiation, we used systems-based approaches and murine EML multipotential hematopoietic precursor cells as a primary model. EML cells give rise to a mixture of self-renewing Lin-SCA+CD34+ cells and partially differentiated non-renewing Lin-SCA-CD34- cells in a cell autonomous fashion. We identified and validated the HMG box protein TCF7 as a key regulator in this self-renewal/differentiation switch, and it operates in the absence of canonical Wnt signaling. We found that TCF7 is the most downregulated transcription factor when CD34+ cells switch into CD34- cells using RNA-Seq. We subsequently identified the target genes bound by TCF7 using ChIP-Seq. We show that TCF7 binds to Runx1 (Aml1) promoter region, and RUNX1 and TCF7 co-regulate. Gene Set Enrichment Analysis suggests that TCF7 primarily acts as a positive regulator of genes preferentially expressed in CD34+ cells. Consistent with this possibility, knocking-down TCF7 represses many up-regulated genes in Lin-CD34+ cells. Finally a network of up-regulated transcription factors of CD34+ cells which defines the self-renewing state was constructed. These studies in EML cells demonstrate fundamental cell-intrinsic properties of the switch between self-renewal and differentiation, and yield valuable insights for manipulating HSCs and other differentiating systems. Examining the transcription factor binding targets of TCF7 and RUNX1.
Project description:Type 2 pre-cDCs are considered as a homogeneous population in the bone marrow. We used single cell RNA sequencing to show that the bone marrow contains two subsets of pre-cDC2s that are commited to give rise to different different cDC2 subsets in peripheral tissues.