Gene expression data from mouse hematopoietic cells, Ikaros wt and null mutant
ABSTRACT: Regulation of lineage potential and transcriptional priming by Ikaros. New insight is provided into a bivalent regulation of lineage priming in the HSC and its lympho-myeloid restricted progeny the LMPP by the lymphoid lineage-determining factor Ikaros Whereas Ikaros is responsible for the activation of a cascade of lymphoid expression programs and for the establishment of lymphoid potential from the HSC to the LMPP it is also responsible for the repression of stem cell and erythroid genetic programs that are incompatible with further lineage restrictions emanating from the LMPP Keywords: Ikaros null versus wt Overall design: Ikaros null versus wt
Project description:Regulation of lineage potential and transcriptional priming by Ikaros. New insight is provided into a bivalent regulation of lineage priming in the HSC and its lympho-myeloid restricted progeny the LMPP by the lymphoid lineage-determining factor Ikaros; Whereas Ikaros is responsible for the activation of a cascade of lymphoid expression programs and for the establishment of lymphoid potential from the HSC to the LMPP it is also responsible for the repression of stem cell and erythroid genetic programs that are incompatible with further lineage restrictions emanating from the LMPP Experiment Overall Design: Ikaros null versus wt
Project description:Hematopoietic stem cells (HSCs) must balance self-renewal and lineage differentiation to regenerate the hematopoietic system throughout life. HSCs exhibit lineage-associated gene expression that keeps them responsive to demands of mature blood production. However, it is not known whether this process, termed lineage priming, directly influences HSC self-renewal. We investigated the link between stemness and lineage priming by attenuating the early lymphoid transcription factor E47 through ID2 over-expression (OE). Transcriptional profiling of ID2 OE HSCs showed down regulation of B-cell factors including EBF1 and FOXO1 with a concomitant increase in stemness programs and myeloerythroid factors including CEBPA and GATA1. This resulted in myeloid commitment bias from the earliest stages of differentiation. HSC self-renewal was strongly affected by this lineage perturbation resulting in an 11-fold expansion of HSCs. Thus, early lymphoid transcription factors antagonize human HSC self-renewal, providing a direct link between differentiation program priming and the maintenance of stem cell self-renewal. Three independent lineage depleted CB samples were transduced with P-CTRL or P-ID2 and injected into 5 mice (30 mice total). From every group of 5 mice, human lin- cells were isolated and GFP+CD34+CD38-CD45RA- HSPCs were sorted by FACS.
Project description:Integration of index sorting and single cell functional assays allowed identification of novel haematopoietic stem cell (HSC) and multiprogenitor subsets (MPP) that differ in their lineage differentiation potential in vitro and in vivo, cell cycle properties and long-term repopulation capacity in the NSG xenograft model. Here we report single cell transcriptomes of CD49f+ HSCs as well as those of CD49f+ Subset1 (CD19- CD38- CD45RA- CD90+ CD49f+ CD34lo CLEC9Ahi, Myelo-erythroid-skewed in vitro but Lymphoid-competent) and CD49f+ Subset2 cells (CD19- CD38- CD45RA- CD90+ CD49f+ CD34hi CLEC9Alo, Myelo-Lymphoid competent but Erythroid-deficient). We also report bulk transcriptomes of pools of 20 cells from HSC/MPP Subset1 (CD19- CD38- CD45RA- CD34lo CLEC9Ahi) and HSC/MPP Subset2 (CD19- CD38- CD45RA- CD34hi CLEC9Alo). Altogether these data show a diffuse transcriptional landscape of the CD49f+ HSC compartment, which is polarised along an axis that separates Myelo-Erythroid and Myelo-Lymphoid lineage-priming. Consistently with their differentiation capacity in vitro, CD49f+ Subset1 cells cluster at the Myelo-Erythroid end of the landscape, while CD49f+ Subset2 cells cluster at the Myelo-Lymphoid end. In addtion, these lineage-priming signatures were found to be more marked in HSC/MPP Subset1 and HSC/MPP Subset2, than in the equivalent CD49f+ subsets. In conclusion, 49f+ Subset1 and 49f+ Subset2 populations have activated distinct transcriptional lineage-priming programmes corresponding to the phenotypic lineage-skewing observed in vitro, that then become reinforced within the broader HSC/MPP pool. Altogether our data shows that lineage-priming and lineage-restriction programmes are initially established within the CD49f+ HSC subset in humans. Overall design: Examination of the genome-wide transcriptome of 192 single CD49f+ HSCs and 192 single cells from two CD49f+ HSC subsets (CD49f+ Subset1 and CD49f+ Subset2), as well as replicates of 20 cells of HSC/MPP Subset1 and HSC/MPP Subset2
Project description:To determine the function of Camkk2 in HSC we performed a microarray analysis on isolated KSL from WT and Camkk2 null mice. Using a threshold of 0.05 for statistical significance (p-value) and a log fold change of expression with absolute value of at least 0.6, 1831 differentially expressed genes (DEGs) were identified out of a total of 29352 genes with measured expression. When compared to WT KSL, 1289 genes were significantly downregulated and 533 genes were upregulated in Camkk2 null HSC. The genes downregulated in Camkk2 null KSL were strongly enriched in HSC, early progenitors and lymphoid-myeloid-affiliated genes (s-myly) primed in HSC. Of note, HSC-affiliated genes found downregulated in Camkk2 KSL included Hlf, Meis1, Pbx-1 and Prdm5 which are 4 of the 8 genes capable to reprogram committed murine blood cells into HSC. The GSEA analysis also showed that genes affiliated with the late progenitor signature and erythroid genes primed in HSC and GMP specific genes (d-my) were significantly upregulated in Camkk2 null KSL. These findings indicate Camkk2 controls crucial transcriptional programs involved in the mechanism of HSC differentiation and lineage commitment. Overall design: Bone marrow was removed from bones of WT and Camkk2 null mice (16 mice/genotypes), and four biological replicates for each genotype were generated. Hematopoietic stem and progenitor cells were isolated based on the expression of Lineage (Lin) markers, c-Kit and Sca-1 expression. Lin-Kit+ Sca1- and Lin-Kit+ Sca1+ (KL and KLS cells) were sorted from mice directly into Buffer RLT (Qiagen). RNA isolation, quality control and all the procedures required for microarray analysis were performed at Sequencing and Genome Technologies Shared Resource (Duke University) according to standard operative procedures.
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. Overall design: Examination of single cell RNA-seq transcriptomes in LMPP isolated from the bone marrow of 4mo and 14mo wild-type C57BL/6J female mice
Project description:Hamey2017 - Blood stem cell regulatory
network (LMPP network)
This model is described in the article:
Reconstructing blood stem
cell regulatory network models from single-cell molecular
Fiona K. Hamey, Sonia Nestorowa,
Sarah J. Kinston, David G. Kent, Nicola K. Wilson, and Berthold
Proceedings of the National Academy of
Sciences of the United States of America
Adult blood contains a mixture of mature cell types, each
with specialized functions. Single hematopoietic stem cells
(HSCs) have been functionally shown to generate all mature cell
types for the lifetime of the organism. Differentiation of HSCs
toward alternative lineages must be balanced at the population
level by the fate decisions made by individual cells.
Transcription factors play a key role in regulating these
decisions and operate within organized regulatory programs that
can be modeled as transcriptional regulatory networks. As
dysregulation of single HSC fate decisions is linked to fatal
malignancies such as leukemia, it is important to understand
how these decisions are controlled on a cell-by-cell basis.
Here we developed and applied a network inference method,
exploiting the ability to infer dynamic information from
single-cell snapshot expression data based on expression
profiles of 48 genes in 2,167 blood stem and progenitor cells.
This approach allowed us to infer transcriptional regulatory
network models that recapitulated differentiation of HSCs into
progenitor cell types, focusing on trajectories toward
megakaryocyte–erythrocyte progenitors and lymphoid-primed
multipotent progenitors. By comparing these two models, we
identified and subsequently experimentally validated a
difference in the regulation of nuclear factor, erythroid 2
(Nfe2) and core-binding factor, runt domain, alpha subunit 2,
translocated to, 3 homolog (Cbfa2t3h) by the transcription
factor Gata2. Our approach confirms known aspects of
hematopoiesis, provides hypotheses about regulation of HSC
differentiation, and is widely applicable to other hierarchical
biological systems to uncover regulatory relationships.
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Project description:Growth factor independent 1 (Gfi1) is a transcriptional repressor originally identified as a common integration site in Moloney-murine-leukemia-virus-induced T-cell leukemia. Gfi1-/- mice display increased apoptosis of developing thymocytes and T lymphopenia; however, there are contradictory reports of the absolute number of Gfi1-/- early T lineage progenitors. We used floxed alleles of Gfi1 crossed to various T-cell-specific Cre transgenes to map the requirements for Gfi1 during lymphoid priming and development. We show that Gfi1 is necessary for the proper formation and function of both lymphoid-primed multipotent progenitors and early T lineage progenitors. These defects correlate with a global inability of Gfi1-/- progenitors to enforce the activation of lymphoid genes including IL7R, Rag1, Flt3 and Notch1. Forced expression of intracellular Notch1 fails to rescue the Gfi1-/- defective lymphoid gene signature or Gfi1-/- T cell development. Instead, activation of Notch1 in Gfi1-/- cells results in a potent synthetic lethal phenotype that is most dramatic in immature thymocytes, but absent in mature peripheral T cells where developmental transcriptional programs are silent. Moreover, we find that the requirement for Gfi1-transcriptional integration of Notch-driven lymphoid transcriptional programs is cell autonomous. Our data indicate that Gfi1 is required at multiple independent stages of lymphoid development. In hematopoietic progenitors Gfi1 is necessary to integrate Notch1 signaling, mediate lymphoid priming, the formation of early T lineage progenitors and subsequent T lineage commitment. Lineage negative cells were purified by magnetic beads from RosaCreERT2 Gfi1 ex4-5 floxed mice and an activated Notch1 signal was introduced using a GFP+ retroviral vector. GFP+ progenitors were FACS-sorted and cultured in semi-solid media for one week to allow sufficient time to to instruct lymphoid differentiation, then replated in 1uM 4-OHT or EtOH control. After an additional 7 days, CFU were disrupted and RNA was isolated for global gene expression using microarrays.
Project description:We identified a new type of bone marrow progenitors termed early innate lymphoid cell progenitor (EILP) using TCF-1 GFP reporter mice. We compared the transcriptomes of early innate lymphoid cell progenitors (EILP) with other early progenitors, including HSC, LMPP, CMP, CLP, ETP and DN3. Overall design: Bone marrow EILP, HSC, LMPP, flt3+ CMP, flt3- CMP, CLP, and thymic ETP and DN3 were obtained by flow cytometric cell sorting. To obtain sufficient numbers of cells for micro-array analysis, we pooled cells from long-term bone marrow chimeric mice. Chimeric mice were constructed by intravenous inoculation of donor bone marrow cells from TCF-1 GFP reporter mice into lethally irradiated (900 rads) CD45-congenic (B6 CD45.1) recipient mice, and were used at 12 weeks of reconstitution. RNA was extracted by Trizol (Qiagen), amplified by Nugene PicoV2 kit (Nugene), and hybridized with Affymetrix Mouse Gene 2.0 ST Array.
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. Overall design: Examination of RNA-seq transcriptome in 3 cell types isolated from the bone marrow of wild-type C57Bl/6J female mice
Project description:Cell fate decisions depend on the interplay between chromatin regulators and transcription factors. Here we show that activity of the Mi-2u Nucleosome Remodeling and Deacetylase (NuRD) complex is controlled by the Ikaros family of lymphoid-lineage determining proteins. Ikaros, an integral component of the NuRD complex in lymphocytes, tethers this complex to active lymphoid differentiation genes, but keeps it in a functionally-poised state. Loss in Ikaros DNA binding activity causes a local increase in Mi-2u chromatin remodeling, histone deacetylation and suppression of lymphoid gene expression. The NuRD complex also redistributes to transcriptionally-poised non-Ikaros gene targets, involved in proliferation and metabolism, inducing their re-activation. Thus release of NuRD from Ikaros regulation blocks lymphocyte maturation and mediates progression to a leukemic state by engaging functionally-opposing epigenetic mechanisms and genetic networks. We used microarrays to detail the global programme of gene expression of mouse DP thymocyte after Ikaros inactivation with dominant negative of Ik at different stage. 8 samples (mouse DP thymocytes from wt, and different stage after Ikaros inactivation) are analyzed Mouse Microarray Expression platforms, Affymetrix Mouse 430 2.0. Examination of different histone modifications and binding sites for Ikaros, Mi2beta in wild type DP thymocytes, and Ikaros knockout thymocytes.