A novel lymphoid-primed progenitor marked by Dach1 downregulation identified with single cell multi-omics
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ABSTRACT: A classical view of blood cell development is that multipotent haematopoietic stem and progenitor cells (HSPCs) become lineage-restricted at defined stages. The Lin–c-kit+Sca1+Flt3+ stage, termed lymphoid-primed multipotent progenitors (LMPPs), have lost megakaryocyte and erythroid potential but are heterogeneous in their fate. Through single cell RNA-sequencing, we identify heterogeneous expression of Dach1 and associated genes in this fraction where it co-expressed with myeloid/stem genes but inversely correlated with lymphoid genes. Through generation of Dach1-GFP reporter mice, we identify a transcriptionally and functionally unique Dach1– subpopulation within LMPPs with lymphoid potential but devoid of myeloid potential. We term these ‘lymphoid-primed progenitors’, or LPPs. These findings define the earliest branch point of lymphoid development in haematopoiesis and a means for their prospective isolation.
Project description:A classical view of blood cell development is that multipotent haematopoietic stem and progenitor cells (HSPCs) become lineage-restricted at defined stages. The Lin–c-kit+Sca1+Flt3+ stage, termed lymphoid-primed multipotent progenitors (LMPPs), have lost megakaryocyte and erythroid potential but are heterogeneous in their fate. Through single cell RNA-sequencing, we identify heterogeneous expression of Dach1 and associated genes in this fraction where it co-expressed with myeloid/stem genes but inversely correlated with lymphoid genes. Through generation of Dach1-GFP reporter mice, we identify a transcriptionally and functionally unique Dach1– subpopulation within LMPPs with lymphoid potential but devoid of myeloid potential. We term these ‘lymphoid-primed progenitors’, or LPPs. These findings define the earliest branch point of lymphoid development in haematopoiesis and a means for their prospective isolation.
Project description:Lymphoid primed multipotent progenitors are a subset of MPPs that are undergoing specification to the lymphoid and myeloid cell fates. The transcription factors Lyl1 and E2A are both essential for the development LMPPs and can form a heterodimeric complex. We examined the consequences of E2A- or Lyl1-deficiency on development of LMPPs and on their gene expression program in comparison with wild-type LMPPs
Project description:Lymphoid primed multipotent progenitors are a subset of MPPs that are undergoing specification to the lymphoid and myeloid cell fates. The transcription factors Lyl1 and E2A are both essential for the development LMPPs and can form a heterodimeric complex. We examined the consequences of E2A- or Lyl1-deficiency on development of LMPPs and on their gene expression program in comparison with wild-type LMPPs We used microarray data to examine the differences in gene expression between control, E2A-/- and Lyl1-/- CD138+ LSK cells.
Project description:Hematopoietic stem cells (HSCs) and lymphoid-primed multi-potential progenitors (LMPPs) are able to initiate both lymphoid and myeloid differentiation. We show here that the transcriptional repressor Gfi1 (growth factor independence 1) implements a specific gene expression program in HSCs and LMPPs that is critical for their survival and lymphoid differentiation potential. We present evidence that Gfi1 is required to maintain expression of genes involved in lymphoid development such as Flt-3, IL7R, Ebf1, Rag1, CCR9 and Notch1 and controls myeloid lineage commitment by regulating expression of genes such as Hoxa9 or M-CSFR. Gfi1 also inhibits apoptosis in HSCs by repressing pro-apoptotic genes such as Bax or Bak. As a consequence, Gfi1-/- mice show defects in self renewal, survival and both myeloid and lymphoid development of HSCs and LMPPs. Co-expression of a Bcl-2 transgene can partially restore the function of HSCs in Gfi1-/- mice, but not the defects in early lymphoid development. Of interest, Gfi1-/- x Bcl-2 transgenic mice show an accelerated expansion of myeloid cells and succumb to a fatal myeloproliferative disease resembling chronic myelomonocytic leukemia (CMML). Our data show that Gfi1 protects HSCs against apoptosis, ensures the proper development of LMPPs and plays a role in the development of myeloid leukemia. We used microarrays to detail the global gene expression changes following knockout of Gfi1 in mouse LSK cells We compared LSK cells isolated from Gfi1 knockout mice with wildtype cells to determine global gene expression changes by microarray analysis
Project description:While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. To determine how distinct progenitors can generate similar downstream lineages, we examined the transcriptional changes that accompany loss of in vivo myeloid potential as common myeloid progenitors (CMPs) differentiate into common dendritic cell progenitors (CDPs), and as lymphoid-primed multipotent progenitors (LMPPs) differentiate into all lymphoid progenitors (ALPs). Microarray studies revealed that Interferon regulatory factor 8 (IRF-8) expression increased during each of these transitions. Competitive reconstitutions using Irf8-/- bone marrow demonstrated cell-intrinsic defects in the formation of CDPs and all splenic dendritic cell subsets. Irf8-/- CMPs and, unexpectedly, Irf8-/- ALPs produced more neutrophils in vivo than their wild type counterparts at the expense of DCs. Retroviral expression of IRF-8 in multiple progenitors led to reduced neutrophil production and increased numbers of DCs, even in the granulocyte-macrophage progenitor (GMP), which does not normally possess conventional DC potential. These data suggest that IRF-8 represses a neutrophil module of development and promotes convergent DC development from multiple lymphoid and myeloid progenitors autonomously of cellular context. CMP (Lineage-c-kithiSca-1-CD11c- CD34+ Flk2+CD16/32-CD115- ) or CDP (Lin-c-kitintSca-1-CD34+Flk2+CD16/32-CD115+) were double sorted from the bone marrow of wild type C57BL/6 mice. RNA was extracted from 10,000-30,000 sorted cells using Trizol (Invitrogen) and linear acrylamide (Ambion), amplified using Affymetrix Two-Cycle Amplification and IVT kits (Affymetrix), and hybridized to Affymetrix Mouse Genome 430 2.0 chips.
Project description:While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. To determine how distinct progenitors can generate similar downstream lineages, we examined the transcriptional changes that accompany loss of in vivo myeloid potential as common myeloid progenitors (CMPs) differentiate into common dendritic cell progenitors (CDPs), and as lymphoid-primed multipotent progenitors (LMPPs) differentiate into all lymphoid progenitors (ALPs). Microarray studies revealed that Interferon regulatory factor 8 (IRF-8) expression increased during each of these transitions. Competitive reconstitutions using Irf8-/- bone marrow demonstrated cell-intrinsic defects in the formation of CDPs and all splenic dendritic cell subsets. Irf8-/- CMPs and, unexpectedly, Irf8-/- ALPs produced more neutrophils in vivo than their wild type counterparts at the expense of DCs. Retroviral expression of IRF-8 in multiple progenitors led to reduced neutrophil production and increased numbers of DCs, even in the granulocyte-macrophage progenitor (GMP), which does not normally possess conventional DC potential. These data suggest that IRF-8 represses a neutrophil module of development and promotes convergent DC development from multiple lymphoid and myeloid progenitors autonomously of cellular context. CMP (Lineage-c-kithiSca-1-CD11c- CD34+ Flk2+CD16/32-CD115- ) or ALP (Lin-Ly6D-B220-c-kit+Flk2+IL7R?+) were double sorted from the bone marrow of wild type C57BL/6 mice. RNA was extracted from 2,000-15,000 sorted cells using Qiagen RNeasy Mini kit, amplified using Nugen pico-amplification kit , and 750 ng of aRNA was hybridized to Illumina MouseRef-8 v 2.0 bead chips Amy,M,Becker
Project description:While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. To determine how distinct progenitors can generate similar downstream lineages, we examined the transcriptional changes that accompany loss of in vivo myeloid potential as common myeloid progenitors (CMPs) differentiate into common dendritic cell progenitors (CDPs), and as lymphoid-primed multipotent progenitors (LMPPs) differentiate into all lymphoid progenitors (ALPs). Microarray studies revealed that Interferon regulatory factor 8 (IRF-8) expression increased during each of these transitions. Competitive reconstitutions using Irf8-/- bone marrow demonstrated cell-intrinsic defects in the formation of CDPs and all splenic dendritic cell subsets. Irf8-/- CMPs and, unexpectedly, Irf8-/- ALPs produced more neutrophils in vivo than their wild type counterparts at the expense of DCs. Retroviral expression of IRF-8 in multiple progenitors led to reduced neutrophil production and increased numbers of DCs, even in the granulocyte-macrophage progenitor (GMP), which does not normally possess conventional DC potential. These data suggest that IRF-8 represses a neutrophil module of development and promotes convergent DC development from multiple lymphoid and myeloid progenitors autonomously of cellular context.
Project description:While most blood lineages are assumed to mature through a single cellular and developmental route downstream of hematopoietic stem cells (HSCs), dendritic cells (DCs) can be derived from both myeloid and lymphoid progenitors in vivo. To determine how distinct progenitors can generate similar downstream lineages, we examined the transcriptional changes that accompany loss of in vivo myeloid potential as common myeloid progenitors (CMPs) differentiate into common dendritic cell progenitors (CDPs), and as lymphoid-primed multipotent progenitors (LMPPs) differentiate into all lymphoid progenitors (ALPs). Microarray studies revealed that Interferon regulatory factor 8 (IRF-8) expression increased during each of these transitions. Competitive reconstitutions using Irf8-/- bone marrow demonstrated cell-intrinsic defects in the formation of CDPs and all splenic dendritic cell subsets. Irf8-/- CMPs and, unexpectedly, Irf8-/- ALPs produced more neutrophils in vivo than their wild type counterparts at the expense of DCs. Retroviral expression of IRF-8 in multiple progenitors led to reduced neutrophil production and increased numbers of DCs, even in the granulocyte-macrophage progenitor (GMP), which does not normally possess conventional DC potential. These data suggest that IRF-8 represses a neutrophil module of development and promotes convergent DC development from multiple lymphoid and myeloid progenitors autonomously of cellular context.
Project description:Declining immune function with age is associated with reduced lymphoid output of hematopoietic stem cells (HSCs). Currently, there is poor understanding of the dynamic changes with age in the heterogeneous multipotent hematopoietic progenitor cell compartment, which regulates output of differentiated lymphoid cells. In this study, we observed progressive and specific loss of lymphoid-primed multipotent progenitor cells (LMPP/MPP4) as young animals began to age. Single cell RNA-seq revealed a concomitant increase in cycling of these progenitors with loss of a lymphoid priming signature. To interrogate functional multipotency of single cells, we developed a novel, feeder-free in vitro assay to concurrently assess lymphoid and myeloid potential. This assay revealed altered clonal composition of the LMPP/MPP4 compartment with aging, where progenitors with B cell and macrophage-restricted potential are lost while functionally multipotent progenitors are preserved. These results pinpoint an age and cellular compartment to focus further interrogation of the drivers of lymphoid cell loss with aging.