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: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.
Project description:miR-142 gene is specifically and abundantly expressed in hematopoietic cells. Mice that lack this miRNA gene develop immunodeficiency and display altered hematopoeisis. We used microarrays to detect whole transcriptome changes in miR-142 null B cells. RNA from purified WT(n=3) and miR-142 KO (n=3) CD19+ B cells was extracted and hybridized to Affymetrix GeneChips. Samples in WT and KO groups are biological replicates and were isolated in age and gender matched mice.
Project description:T cells are critical for modulating immune responses. miRNAs are small, noncoding RNAs and play a significant role in T cell responses. miR-142 is a hematopoietic specific miRNA. To explore the potential role of miR-142 in regulating T cell responses, we generated mutant mice bearing a targeted deletion of the miR-142 gene. We used microarrays to detail the global programme of gene expression underlying the profile changes between miR-142 KO and WT T cell and identified distinct classes of up-regulated genes during this process. miR-142 KO mice and WT littermates (biological triplicates) matched with age and sex were selected. T cells were purified from spleens by negative selection and processed for RNA isolation and hybridization on Affymetrix microarrays.
Project description:CD69 is a transmembrane protein expressed on the surface of activated leukocyte. The ligand for CD69 and the intracellular signaling pathway of this molecule are yet unknown. It is widely used as a marker of activated lymphocyte, but its function in immune system is not known. We used micro-array to define genes whose expression is regulated by activation antigene CD69. CD4 T cells were isolated from the spleen of wt B6 and CD69-deficient B6 mice and in vitro activated with anti-CD3/anti-CD28 coated beads. On one groupe of wt B6 cells, CD69 was activated using a anti-CD69 and secoundary antibody. RNA extraction and hybridization on Affymetrix microarrays was performed for wt B6, CD69-activated wt B6 and CD69-deficient B6 CD4 T cells.