Project description:Analysis of Lin-c-Kit+Sca-1- haematopoietic stem cells (HSCs) expressing the Nup98-HoxD13 (NHD13) fusion gene. NHD13 induces myelodysplastic syndrome (MDS) in mice. Results provide insight into the molecular basis of the myelodysplastic phenotype WT mouse HSCs were compared to an NHD13 mutant sequenced in triplicate on a HiSeq 2000
Project description:Analysis of Lin-c-Kit+Sca-1- haematopoietic stem cells (HSCs) expressing the Nup98-HoxD13 (NHD13) fusion gene. NHD13 induces myelodysplastic syndrome (MDS) in mice. Results provide insight into the molecular basis of the myelodysplastic phenotype
Project description:Analysis of musashi2 contribution towards maintaing myelodysplastic phenotype in stem cells. We find that musashi2 plays an integral role in maintaining the myelodysplastic phenotype Control, NUP98-HOXD13; NHD13, NHD13/MSI2 bone marrow was transplated allowed to engraft into lethally irradiated congenic CD45.1 animals. Mice were then fed doxycycline to induce MSI2 overexpression. Mice were induced for 3 months and then CD45.2 Lineage lo Sca1+ and Kit+ cells were sorted and then assessed for gene expression.
Project description:Loss of function TET2 mutations are frequently seen in myelodysplastic syndrome (MDS) patients. Previous studies have demonstrated that TET2 deficiency enhances maintenance of MDS hematopoietic stem and progenitor cells (HSPCs). Nonetheless, the pathogenic role of TET2 in MDS progression remains elusive. Here, we demonstrate Tet2 knockout (KO) markedly accelerated malignant transformation in Nup98-HoxD13 (NHD13) transgenic mice and promotes leukemogenesis of HoxA9 transduction/transplant mice. Consistently, low TET2 level cooperating with high HOXA9 level predicts poor outcome of MDS patients. Notably, Tet2 KO conferred a clonal advantage to the HSPCs of NHD13 mice. Whole-exome sequencing revealed that Tet2 KO facilitates accumulation of mutations at genes associated with leukemogenesis, including Arih2, whose loss of function promotes MDS cells proliferation. Using 5-hydroxymethylcytosine immunoprecipitation coupled with high-throughput sequencing analysis, we found while Tet2 deletion decreased overall 5hmC levels, it also increased 5hmC distribution at certain mutation loci such as Arih2. Vitamin C treatment, which mimics Tet2/Tet3 restoration, blocked disease progression in Tet2-deficient NHD13 mice. Collectively, our findings demonstrate that TET2 activity governs occurrence of secondary mutations in MDS HSPCs, providing a rationale for enhancing TETs function to block MDS-malignant transformation.
Project description:Loss of function TET2 mutations are frequently seen in myelodysplastic syndrome (MDS) patients. Previous studies have demonstrated that TET2 deficiency enhances maintenance of MDS hematopoietic stem and progenitor cells (HSPCs). Nonetheless, the pathogenic role of TET2 in MDS progression remains elusive. Here, we demonstrate Tet2 knockout (KO) markedly accelerated malignant transformation in Nup98-HoxD13 (NHD13) transgenic mice and promotes leukemogenesis of HoxA9 transduction/transplant mice. Consistently, low TET2 level cooperating with high HOXA9 level predicts poor outcome of MDS patients. Notably, Tet2 KO conferred a clonal advantage to the HSPCs of NHD13 mice. Whole-exome sequencing revealed that Tet2 KO facilitates accumulation of mutations at genes associated with leukemogenesis, including Arih2, whose loss of function promotes MDS cells proliferation. Using 5-hydroxymethylcytosine immunoprecipitation coupled with high-throughput sequencing analysis, we found while Tet2 deletion decreased overall 5hmC levels, it also increased 5hmC distribution at certain mutation loci such as Arih2. Vitamin C treatment, which mimics Tet2/Tet3 restoration, blocked disease progression in Tet2-deficient NHD13 mice. Collectively, our findings demonstrate that TET2 activity governs occurrence of secondary mutations in MDS HSPCs, providing a rationale for enhancing TETs function to block MDS-malignant transformation.
Project description:T-cell Acute Lymphoblastic Leukaemia (T-ALL) can be classified into a number of subfamilies, including those that overexpress TAL1/LMO, TLX1/3 and HOXA transcription factors. Whilst it has been previously shown in mouse models that TAL1/LMO transcription factors induce thymocyte self-renewal, whether this is the case for other transcription factor subclasses is currently unknown. To address this, we have studied vav-Nup98-HoxD13-transgenic (NHD13-Tg) mice, a model of HOXA-driven T-ALL, which overexpress HOXA transcription factors throughout haematopoiesis and display features of myelodysplastic syndrome in the bone marrow along with T-cell developmental abnormalities in the thymus and subsequent development of T-ALL in approximately 15% of mice. Thymocytes from preleukemic NHD13-Tg mice could engraft long-term in serial transplantation assays, demonstrating that NHD13-Tg thymocytes have acquired self-renewal capacity. Transcriptome analysis showed that NHD13-Tg thymocytes exhibited a Stem Cell like transcriptional program which closely resembled that of Lmo2 transgenic thymocytes, including Lmo2 itself and the critical Lmo2 cofactor Lyl1, suggesting a common mechanism of thymocyte self-renewal in these models. To determine whether Lmo2/Lyl1 are required for NHD13-induced thymocyte self-renewal, NHD13-Tg mice were crossed with Lyl1 knockout mice to generate NHD13-Tg mice lacking Lyl1. This showed that Lyl1 is essential for expression of the stem cell-like gene expression program in NHD13-Tg thymocytes and for thymocyte self-renewal. Surprisingly however, absence of Lyl1 accelerated the onset of T-ALL in NHD13-Tg mice. These studies demonstrate that Lyl1 is essential for self-renewal of NHD13-Tg thymocytes, suggesting that Lmo2 and Lyl1 may mediate thymocyte self-renewal induced by a variety of T-cell oncogenes. However, whilst Lyl1-induced thymocyte self-renewal is essential for Lmo2-driven T-cell leukemia, NHD13 can also promote T-ALL via an alternative pathway.
Project description:Investigation of differences in gene expression between NHD13 mice with myelodysplastic syndrome and wild type littermates. RNA was harvested from Lineage negative Kit positive cells purified from mice transgenic for NHD13 or wild type littermates. Samples were pooled in groups of 3. 3 replicates were performed for each genotype.