Project description:To investigat the role of Srp72 in hematopoiesis and the development of myelodysplasia and bone marrow aplasia, we generated a transgenic mouse strain with a Srp72 KO strand. Heterozygous loss of SRP72 in mice is not associated with major changes in steady-state hematopoiesis, although we did observe mild reductions in peripheral blood and BM cellularity. Moreover, we also detected minor changes within the stem/progenitor compartment as well as in their propensity to generate a balanced lineage output. We did not observe the development of any haematological disorder, thus the Srp72+/- mouse model only partially recapitulates the more severe aplasia and myelodysplasia observed in families with inherited SRP72 lesions. We thereafter extracted RNA from LT-HSCs of old mice to observe transcriptional changes in those mice. Interestingly, gene expression analysis demonstrated that genes encoding secreted factors, including cytokines and cell-surface receptors, were transcriptionally down-regulated in Srp72+/- animals. This can potentially provide mechanistic insights into why SRP72 lesions are associated with the development of severe aplasia and myelodysplasia in humans.
Project description:Loss of Phf6 prevents the functional decline and immunophenotypic changes associated with age-related, long-term repopulating hematopoietic stem cell (LT-HSC) exhaustion. To identify the underlying molecular mechanisms that account for these differences, we performed RNA-seq profiling of LT-HSCs isolated from the bone marrow of Phf6 wild-type and knock-out, young (16-week-old) and aged (24-month-old) C57BL/6 mice. Our analysis revealed that LT-HSCs isolated from 24-month-old, Phf6 knockout mice retained the molecular signatures associated with young LT-HSCs whereas LT-HSCs isolated from aged, Phf6 wild-type mice acquired signatures consistent with HSC exhaustion. Mechanistically, these data revealed important roles for key metabolic pathways including glutathione metabolism and sterol biosynthesis, as well as cell-cell interaction and signaling pathways such as the interferon and TGF-beta responses.
Project description:We have developed a new conditional transgenic mouse showing that MLL-ENL, at an endogenous-like expression level, induces leukemic transformation selectively in LT-HSCs. To investigate the molecular mechanism of leukemic transformation in LT-HSCs conditionally expressing MLL-ENL, we preliminarily performed comprehensive gene expression profiling of CreER-transduced LT-HSCs and ST-HSCs using cDNA microarray analysis. For initial screening of candidate genes invloved in the leukemic transformation, total RNA was extracted from colony-forming cells derived from LT-HSCs and ST-HSCs transduced with CreER or mock. Four samples were analyzed, and CreER-transduced LT/ST-HSC-derived cells were compared with mock-transduced LT/ST-HSC-derived cells, while CreER/mock-transduced LT-HSC-derived cells were compared with CreER/mock-transduced ST-HSC-derived cells.
Project description:We have developed a new conditional transgenic mouse showing that MLL-ENL, at an endogenous-like expression level, induces leukemic transformation selectively in LT-HSCs. To investigate the molecular mechanism of leukemic transformation in LT-HSCs conditionally expressing MLL-ENL, we preliminarily performed comprehensive gene expression profiling of CreER-transduced LT-HSCs and ST-HSCs using cDNA microarray analysis.