Project description:The MLL-PTD mutation is found in patients with MDS and AML, and not in other haematological malignancies. Previously, we showed that Mll-PTD knock-in heterozygous mice present with several MDS-associated features, such as increased self-renewal and apoptosis in HSPCs, expansion of the myeloid progenitor population, ineffective haematopoiesis, and skewed myeloid differentiation. MLL is an epigenetic regulator: its C-terminal Su[var]3–9, enhancer of zeste, trithorax (SET) domain has methyltransferase activity on lysine 4 on histone 3 (H3K4), which is retained in the MLL-PTD mutant. To clarify the effects of MLL-PTD on target gene regulation, we performed H3K4me3 ChIP-Seq analysis of LSKs isolated from WT and Mll-PTD knock-in heterozygous mice.
Project description:The MLL-PTD mutation is found in patients with MDS and AML, and not in other hematological malignancies. Previously, we showed that Mll-PTD knock-in heterozygous mice (MllPTD/WT mice) present with several MDS-associated features. However, these phenotypes are insufficient to constitute bona fide MDS. MllPTD/WT mice do not generate MDS or AML in primary or transplant recipient mice. This suggests that additional genetic and/or epigenetic defects are necessary for transformation to MDS or AML. In secondary AML and de novo AML, MLL-PTD mutation is significantly associated with mutations in RUNX1 and with the FLT3-ITD mutations. In fact, the combination of MLL-PTD with the FLT3-ITD allele leads to AML in mice. We combined the MLL-PTD with RUNX1 mutant proteins, in order to generate a new mouse model for MDS. We generated MllPTD/WT/Runx1Flox/Flox/Mx1-Cre mice to model loss-of-function RUNX1 mutations. To test the significance of HIF-1α in this model, we also generated MllPTD/WT/Runx1Flox/Flox/Hif-1αFlox/Flox/Mx1-Cre mice and genetically eliminated Hif-1α expression. We analyzed gene expression variations in the HSPCs comparing the MllPTD/WT/Runx1∆/∆ with or without HIF-1α abrogation.
Project description:In acute myeloid leukemia (AML), the mixed lineage leukemia (MLL) gene may be rearranged to generate a partial tandem duplication (PTD), or fused to partner genes through a chromosomal translocation (tMLL). In this study, we first explored the differentially expressed genes between MLL-PTD and tMLL using gene expression profiling of our cohort (15 MLL-PTD and 10 tMLL) and one published data set. The top 250 probes were chosen from each set, resulting in 29 common probes (21 unique genes) to both sets. The selected genes include four HOXB genes, HOXB2, B3, B5, and B6. The expression values of these HOXB genes significantly differ between MLL-PTD and tMLL cases. Clustering and classification analyses were thoroughly conducted to support our gene selection results. Second, as MLL-PTD, FLT3-ITD, and NPM1 mutations are identified in AML with normal karyotypes, we briefly studied their impact on the HOXB genes. Another contribution of this study is to demonstrate that using public data from other studies enriches samples for analysis and yields more conclusive results.
Project description:We wanted to investigate the effects of Dot1l deletion on gene expression in LSKs and GMPs of C57/BL6 mice Aberrant Hox gene activation is a recurrent feature in several different types of human leukemia, including leukemias with rearrangements of the mixed lineage leukemia (MLL) gene. In this study, we demonstrate that Hox gene expression is controlled by higher degree H3K79 methylation in acute myeloid leukemia (AML). We show that the deposition of progressive H3K79 methylation states at the genomic loci of critical Hox genes is dependent on the interaction of the H3K79 methyltransferase Dot1l with Af10, a protein that is found in the Dot1l complex isolated from diverse cell types. Furthermore, abrogation of the Dot1l-Af10 interaction reverses aberrant epigenetic profiles found in the leukemia epigenome and impairs the transforming ability of mechanistically distinct AML oncogenes. Lineage negative Sca-1 positive Kit positive (LSK) cells and granulocyte macrophage progenitors (GMPs) were sorted from Dot1 wt/wt x Mx-Cre mice or Dot1l fl/fl x Mx-Cre mice were injected with PIPC. PIPC injection induced biallelic deletion of the Dot1l allele in the Dot1l fl/fl mice but not the Dot1l wt/wt mice. The Dot1l wt/wt LSKs and GMPs were compared to the Dot1l -/- counterparts by RNA extraction and Microarrays.
Project description:The pathways by which oncogenes, such as MLL-AF9, initiate transformation and leukemia in humans and mice are incompletely defined. In a study of target cells and oncogene dosage, we found that Mll-AF9, when under endogenous regulatory control, efficiently transformed LSK (Lin- Sca1+ c-kit+) stem cells while committed granulocyte-monocyte progenitors (GMPs) were transformation-resistant and did not cause leukemia. Mll-AF9 was expressed at higher levels in hematopoietic stem (HSC) than GMP cells. Mll- AF9 gene dosage effects were directly shown in experiments where GMPs were efficiently transformed by the high dosage of Mll-AF9 resulting from retroviral transduction. Mll-AF9 up-regulated expression of 196 genes in both LSK and progenitor cells, but to higher levels in LSKs than in committed myeloid progenitors. Experiment Overall Design: Comparison of gene expression profiles among four types of hematopoietic cells (GMP, CMP, CLP and HSC), FACS sorted from wild type and Mll-AF9 knock-in mice. The goal was to identify genes differentially expressed in each Mll-AF9 cell type compared to the corresponding wild type cells.
Project description:LSKs(lineage-, Sca-1+, c-kit+ cells) in bone marrow from wild type (WT) and MC5R-knockout (KO) mice after after irradiation were isolated to explore the differentially expressed genes by RNA-seq.
Project description:LSKs (lineage-, Sca-1+, c-kit+ cells) in the bone marrow from wild type (WT) and Tespa1-knockout (KO) mice at day 13 after 5.0 Gy irradiation were isolated to explore the differentially expressed genes by RNA-seq.
Project description:LSKs(lineage-, Sca-1+, c-kit+ cells) in the bone marrow from normal and 5-Fluorouracil (5-FU) treated (Day 9) wild type (WT) and Tespa1-knockout (KO) mice were isolated to explore the differentially expressed genes by RNA-seq.
Project description:To determine role of Notch signaling in AML leukemia initiating cells we used a conditional mouse knock-in model of Notch1-IC to induce Notch1-IC expression in MLL-AF9 transformed LGMP. WT and Notch1-IC+ LGMP were analyzed to determined genes controlled by Notch signaling. 12 weeks old wt lethaly irradiated mice were transplanted with 50000 cKit+ MLL-AF9-IRES-YFP infected cells from MLL-AF9 EF1 wt/wt ROSAwt/CreERT2 or MLL-AF9 EF1 wt/lsl-N1-IC ROSAwt/CreERT2 mice + 250000 support wt total bone marrow cells. 4 weeks after transplant mice were injected 2 times with tamoxifen (0.2mg/g body weight) every other day. Mice were sacrificed and analyzed 6 days after last injection. LGMP were flow purified for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Purpose: The goal of this study was to compare the transcriptome of FACS-purified bone marrow BL/6 (WT) or CD93-/- (KO) LSKs and BL/6 (WT) or CD93-/- (KO) LSCs. We also compared the transcriptome of FACS-purified bone marrow LSCs isolated from BL/6 mice previously treated with MCP or Veh in vivo. Methods: Transcriptomic analysis of CD93-proficient and deficient bone marrow LSKs and CML LSCs or CML LSCs upon treatment with MCP or Veh, were assessed in biological replicates using Illumina. qRT–PCR validation was performed using SYBR Green assays. Results: We mapped around 30 million sequence reads per sample to the mouse genome (GRCm38 - mm10) and identified expressed transcripts in studied samples. RNA-seq data confirmed stable expression of known housekeeping genes. Differentially expressed genes among conditions were identified with a fold change ≥1.5 and FDR p-value <0.05. Conclusions: Our study represents the first detailed transcriptome analysis of CD93-proficient and deficient bone marrow LSKs and LSCs isolated from BM of naïve and CML mice generated by RNA-seq. technology. Our results show that CD93-signaling triggers stem cell maintenance- and cell proliferation-promoting signaling pathways in CML LSCs. In addition, we showed transcriptome analysis of FACS-purified bone marrow LSCs isolated from BL/6 (WT) mice which were previously treated with MCP or Veh in vivo. Our results show that MCP treatment suppresses the stem cell maintenance- and cell proliferation-promoting signaling pathways in CML LSCs.