Project description:To gain insight into how miR-142 deficit drives a BC-like transformation, we performed RNA-seq on bone marrow (BM) Lin-Sca-1+c-Kit+ cells (LSKs) harvested from normal miR-142+/+ (wt) and miR-142−/− (miR-142 KO) mice, as well as from leukemic miR-142+/+ BCR-ABL (CP CML) and miR-142−/− BCR-ABL (BC CML) mice, two weeks after BCR-ABL induction. We then performed gene expression profiling analysis using data obtained from RNA-seq of 24 samples of LSK cells from 4 mouse strains (KO vs WT, KO CML vs CML).
Project description:2 types of dendritic cells (DCs) can be generated in vitro in the presence of Flt3-L: CD4+ equivalent CD24- DCs and CD8+ equivalent CD24+ DCs. miR-142-/- mice show a severe defect in the generation of CD4+ equivalent CD24- DCs. To understand the underlying mechanism, RNA expression was analyzed by Affymetrix microarray from the 2 in vitro subtypes of DCs derived from miR-142+/+ and miR-142-/- bone marrow cells. We used microarrays to detail the global programme of gene expression in the presence or absence of miR-142 in in vitro derived DCs. Bone marrow cells from miR-142+/+ and miR-142-/- C57Bl/6 mice were isolated and incubated in the presence of Flt3-L for 8 days. in vitro derived wt and ko dendritic cells were devided into CD4+ and CD8+ equivalent DCs by FACS and sorted with a FACS-Aria. RNA was isolated and gene expression was investigated
Project description:ATAC-seq profiling of Nfat5 KO and wild type macrophages derived from bone marrow (primary cells), treated or not with Lipopolysaccharide (LPS).
Project description:High ploidy large cytoplasmic megakaryocytes (LCM) are critical negative regulators of hematopoietic stem cells (HSC) and are responsible for platelet formation. Using a mouse knockout model with normal megakaryocyte numbers but essentially devoid of LCM (MK-LCM KO), we demonstrated a pronounced increase in bone marrow HSC concurrent with endogenous mobilization and extramedullary hematopoiesis. When HSC isolated from a MK-LCM KO microenvironment were transplanted in lethally irradiated mice, the absence of LCM increased HSC in BM, blood and spleen. Severe thrombocytopenia was observed in animals with diminished LCM, although there was no change in megakaryocyte ploidy distribution. In contrast, WT HSC-generated LCM regulated a normal HSC pool and prevented thrombocytopenia. The present label-free quantitative LC-MSMS data was used to determine proteins that are differentially expressed in bone marrow cells of MK-LCM WT versus MK-LCM KO mice.
Project description:MiR-142 is dynamically expressed and plays a regulatory role in hematopoiesis. Based on the simple observation that miR-142 levels are significantly lower in CD34+CD38- cells from blast crisis (BC) chronic myeloid leukemia (CML). CML patients compared with chronic phase (CP) CML patients (p=0.002), we hypothesized that miR-142 deficit plays a role in BC transformation. To test this hypothesis, we generated a miR-142 KO BCR-ABL (i.e., miR-142−/−BCR-ABL) mouse by crossing a miR-142−/− mouse with a miR-142+/+BCR-ABL mouse. While the miR-142+/+BCR-ABL mice developed and died of CP CML, the miR-142−/−BCR-ABL mice developed a BC-like phenotype in the absence of any other acquired gene mutations and died significantly sooner than miR-142+/+BCR-ABL CP controls (p=0.001). Leukemic stem cell (LSC)-enriched Lineage-Sca-1+c-Kit+ cells (LSKs) from diseased miR-142−/−BCR-ABL mice transplanted into congenic recipients, recapitulated the BC features thereby suggesting stable transformation of CP-LSCs into BC-LSCs in the miR-142 KO CML mouse. Single cell (sc) RNA-seq profiling showed that miR-142 deficit changed the cellular landscape of the miR-142−/−BCR-ABL LSKs compared with miR-142+/+BCR-ABL LSKs with expansion of myeloid-primed and loss of lymphoid-primed factions. Bulk RNA-seq analyses along with unbiased metabolomic profiling and functional metabolic assays demonstrated enhanced fatty acid β-oxidation (FAO) and oxidative phosphorylation (OxPhos) in miR-142−/−BCR-ABL LSKs vs miR-142+/+BCR-ABL LSKs. MiR-142 deficit enhanced FAO in miR-142−/−BCR-ABL LSKs by increasing the expression of CPT1A and CPT1B, that controls the cytosol-to-mitochondrial acyl-carnitine transport, a critical step in FAO. MiR-142 deficit also enhanced OxPhos in miR-142−/−BCR-ABL LSKs by increasing mitochondrial fusion and activity. As the homeostasis and activity of LSCs depend on higher levels of these oxidative metabolism processes, we then postulate that miR-142 deficit is a potentially druggable target for BC-LSCs. To this end, we developed a novel CpG-miR-142 mimic oligonucleotide (ODN; i.e., CpG-M-miR-142) that corrected the miR-142 deficit and alone or in combination with a tyrosine kinase inhibitor (TKI) significantly reduced LSC burden and prolonged survival of miR-142−/−BCR-ABL mice. The results from murine models were validated in BC CD34+CD38- primary blasts and patient-derived xenografts (PDXs). In conclusion, an acquired miR-142 deficit sufficed in transforming CP-LSCs into BC-LSCs, via enhancement of bioenergetic oxidative metabolism in absence of any additional gene mutations, and likely represent a novel therapeutic target in BC CML.