Project description:miR-29a/b1 was reported to be involved in the regulation of reproductive function in female mice, but the underlying molecular mechanisms were not clear. In this study, female mice lacking miR-29a/b1 showed a delay in vaginal opening, irregular estrus cycles, ovulation disorder and infertility. However, the development of egg was normal in mutant mice and the ovulation disorder could be rescued by the superovulation treatment. The plasma level of luteinizing hormone (LH) was significantly lower in the mutant mice. Using iTRAQ coupled with LC-MS/MS, we found that the deficiency of miR-29a/b1 in mice resulted in an abnormal expression of a number of proteins involved in vesicular transport and secretion in the pituitary gland. The miR-29a/b1 targeting gene Dnmt3a and Hdac4 were up-regulated in the pituitary of miR-29a/b1 knockout mice suggesting that these two epigenetic writers may be the upstream causes for these phenotype changes due to miR-29a/b1 deficiency. These findings demonstrated that miR-29a/b1 is indispensable for the function of the reproductive axis through regulating LH secretion in the pituitary gland.
Project description:Umbilical cord blood (CB) is a non-invasive, convenient and broadly used source of hematopoietic stem cells (HSCs) for allogeneic stem cell transplantation. However, limiting numbers of HSCs remain a major constraint for its clinical application. One feasible option would be to expand HSCs to improve therapeutic outcome, however available protocols and the molecular mechanisms governing the self-renewal of HSC are unclear. Here we show that ectopic expression of a single miRNA, miR-125a, in purified murine and human multipotent progenitors (MPP) resulted in increased self-renewal and robust long-term multi-lineage repopulation in transplanted recipient mice. Using quantitative proteomics and Western blot analysis, we identified a restricted set of miR-125a targets which revealed the involvement of the MAP kinase signaling pathway in conferring long-term repopulating capacity to multipotent progenitors in human and mice. Our findings offer the innovative potential to use MPP with enhanced self-renewal activity to augment limited sources of HSC to improve clinical protocols.
Project description:Cytosine methylation is an epigenetic mark usually associated with gene repression. Despite a requirement for de novo DNA methylation for differentiation of embryonic stem cells, its role in somatic stem cells is unknown. Using conditional ablation, we show that loss of either, or both, Dnmt3a or Dnmt3b, progressively impedes hematopoietic stem cell (HSC) differentiation during serial in vivo passage. Concomitantly, HSC self-renewal is immensely augmented in absence of either Dnmt3, particularly Dnmt3a. Dnmt3-KO HSCs show upregulation of HSC multipotency genes and downregulation of early differentiation factors, and the differentiated progeny of Dnmt3-KO HSCs exhibit hypomethylation and incomplete repression of HSC-specific genes. HSCs lacking Dnmt3a manifest hyper-methylation of CpG islands and hypo-methylation of genes which are highly correlated with human hematologic malignancies. These data establish that aberrant DNA methylation has direct pathologic consequences for somatic stem cell development, leading to inefficient differentiation and maintenance of a self-renewal program. Reduced representation bisulfite sequencing (MspI,~40-220bp size fraction) of secondarily-transplanted wild-type and Dnmt3a conditional knockout hematopoietic stem cells. We used microarrays to detail the global expression of genes in secondarily-transplanted control-HSCs and Dnmt3a-KO-HSCs.
Project description:The fate options of hematopoietic stem cells (HSCs) include self-renewal, differentiation, migration and apoptosis, but the interaction between intracellular Ca2+ and cytoplasmic chaperon protein in regulating fate options of long term-HSCs (LT-HSC) is unknown. We created a S100A6 conditional knockout mouse model in the hematopoietic system and our studies showed that in S100A6KO, the number of LT-HSCs was significantly reduced and HSCs engrafted poorly. After 5FU challenge, the frequency of S100A6KO HSCs remained significantly low. Our data showed that S100A6 failed to self-renew through Akt pathway in an intracellular calcium (Cai2+)-dependent manner. Expression profiling of S100A6KO obtained from gene signatures revealed that cytosolic calcium level and proteins translocation to mitochondria were decreased. Mitochondrial oxidative phosphorylation was impaired in S100A6KO. Proteomic data indicated Hsp90 protein and chaperonin family were reduced. Our findings demonstrated that S100A6 regulates fate options of HSCs self-renewal through integrating Akt signaling, specifically governing mitochondria metabolic function and protein quality.
Project description:Dnmt3a is the most recurrently mutated gene in clonal hematopoiesis (CH), and it is a critical regulator of hematopoietic stem cells (HSCs). Conditional deletion of Dnmt3a in mouse HSC results in enhanced self-renewal but impaired differentiation. Dnmt3a encodes for a de novo DNA methyltransferase enzyme but both mouse and human cells with loss of Dnmt3a show minimal change in DNA methylation levels which do not correlate with gene expression differences. To understand if there are methylation differences between control and mutant (R878H) Dnmt3a, we are performing WGBS.
Project description:To investigate the effect of gene alteration of Miat and Mtdh in mouse stem-like MB cells. by canonical oncogenic signaling to maintains the self-renewal capacity of a population of tumorigenic stem-like medulloblastoma cells that are resistant to cytotoxic therapy. by canonical oncogenic signaling to maintains the self-renewal capacity of a population of tumorigenic stem-like medulloblastoma cells that are resistant to cytotoxic therapy. Miat and Mtdh cooperate to promote medulloblastoma tumorigenesis and treatment resistance by regulating the biogenesis of a subset of microRNAs that target genes involved in these processes.
Project description:To investigate the effect of gene alteration of Miat in mouse stem-like MB cells. by canonical oncogenic signaling to maintains the self-renewal capacity of a population of tumorigenic stem-like medulloblastoma cells that are resistant to cytotoxic therapy. by canonical oncogenic signaling to maintains the self-renewal capacity of a population of tumorigenic stem-like medulloblastoma cells that are resistant to cytotoxic therapy. Miat and Mtdh cooperate to promote medulloblastoma tumorigenesis and treatment resistance by regulating the biogenesis of a subset of microRNAs that target genes involved in these processes.
Project description:DNMT3A mutations are observed in myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Here we investigated the impact of conditional hematopoietic Dnmt3a loss on disease phenotype in primary mice. Dnmt3a ablation led to a lethal, fully penetrant myeloproliferative neoplasm with myelodysplasia (MDS/MPN) characterized by marked, progressive hepatomegaly that was transplantable. We detected expanded stem/progenitor populations in the liver of Dnmt3a-ablated mice. Homing studies showed that Dnmt3a-deleted bone marrow cells preferentially migrated to the liver. Hence, in addition to the established role of Dnmt3a in regulating self-renewal, Dnmt3a regulates tissue tropism and limits myeloid progenitor expansion in vivo.
Project description:DNMT3A mutations are observed in myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and acute myeloid leukemia (AML). Here we investigated the impact of conditional hematopoietic Dnmt3a loss on disease phenotype in primary mice. Dnmt3a ablation led to a lethal, fully penetrant myeloproliferative neoplasm with myelodysplasia (MDS/MPN) characterized by marked, progressive hepatomegaly that was transplantable. We detected expanded stem/progenitor populations in the liver of Dnmt3a-ablated mice. Homing studies showed that Dnmt3a-deleted bone marrow cells preferentially migrated to the liver. Hence, in addition to the established role of Dnmt3a in regulating self-renewal, Dnmt3a regulates tissue tropism and limits myeloid progenitor expansion in vivo.
Project description:Gene expression profiling and proteome analysis of normal and malignant hematopoietic stem cells have firmly established the existence of shared core stemness properties. However, the discordance between mRNA and protein signatures underscores an important role for post-transcriptional regulation by miRNAs in governing this critical nexus. Here, we identify miR-130a as a regulator of hematopoietic stem cell (HSC) self-renewal and lineage differentiation. Integration of mass spectrometry and chimeric AGO2 eCLIP-seq identify TBL1XR1 as a primary miR-130a target. TBL1XR1 loss of function impairs lymphoid differentiation and expands long-term (LT)-HSC. This post-transcriptional regulation by miR-130a is usurped in t(8;21) acute myeloid leukemia (AML). Reduction of miR-130a levels in t(8;21) AML cells results in altered chromatin binding and composition of the AML1-ETO complex, demonstrating that miR-130a is critical for maintaining the oncogenic molecular program mediated by AML1-ETO. Our study establishes that comprehensive identification of the miRNA targetome within primary tissue enables the discovery of novel genes and molecular networks underpinning stemness properties of normal and leukemic cells.