Project description:Genome wide DNA methylation profiling of leukemia stem, blast cells obtained from 15 AML patients and of normal hematopoietic stem/progenitor cells from 5 normal bone marrow. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across approximately 450,000 CpGs in the samples. Samples included 20 leukemia stem cells, 24 blast cells and 30 normal hematopoietic stem and progenitor cells (6 different types from 5 normal bone marrows).
Project description:Myosin heavy chain 9 (MYH9) gene encodes a protein named non-muscle heavy chain IIA (NMHC IIA), interacting with actin and participating in various biological processes. Mutations in MYH9 cause an array of autosomal dominant disorders, known as MYH9-related diseases (MYH9-RD). However, the role of MYH9 in normal hematopoiesis remains largely unexplored. By using Mx1-cre Myh9 conditional knockout mice, we established an inducible system to precisely inactivate Myh9 function in hematopoietic cells in vivo. The results showed that deletion of Myh9 led to severe defects in hematopoiesis, characterized by pancytopenia, drastic decreases of hematopoietic stem/progenitor cells (HSPC), and bone marrow failure, causing early lethality in mice. The defect in hematopoiesis caused by Myh9 ablation is cell autonomous. In addition, Myh9 deletion impairs HSPC repopulation capacity and increases apoptosis. RNA sequencing results revealed significant alterations in the expression of genes related to HSC self-renewal and maintenance, while multiple signal pathways were also involved, including genes for HSC and myeloid cell development, intrinsic apoptosis, targets of mTOR signaling, and maturity of hematopoietic cells. Collectively, our findings suggest an essential role for Myh9 in the survival and maintenance of HSPC in normal hematopoiesis.
Project description:U2AF1 is involved in the recognition of the 3’ splice site during pre-mRNA splicing. Mutations in U2AF1 are frequently observed in myelodysplastic syndromes. However, the role of wild-type U2AF1 in normal hematopoiesis has remained elusive. Using a novel conditional U2af1 knockout allele, we have found that deletion of U2af1 results in profound defects in hematopoiesis characterized by pancytopenia, ablation of hematopoietic stem/progenitor cells (HSPC) leading to bone marrow failure and early lethality in mice. U2af1 deletion impairs HSPC function and repopulation capacity. U2af1 deletion also causes increased DNA damage and reduced survival in hematopoietic progenitors. RNA sequencing analysis reveals significant alterations in the expression of genes related to HSC maintenance, cell proliferation and DNA damage response-related pathways in U2af1-deficient HSPC. U2af1 deficiency also induces splicing alterations in genes important for HSPC function. Collectively, these results suggest an important role for U2af1 in the maintenance and function of HSPC in normal hematopoiesis. A better understanding of the normal function of U2AF1 in hematopoiesis is important for development of appropriate therapeutic approaches for U2AF1 mutant induced hematologic malignancies.