X-chromosome aneuploidies have long been associated with human cancers, but causality has not been established. In mammals, X-chromosome inactivation (XCI) is triggered by Xist RNA to equalize gene expression between the sexes. Here we delete Xist in the blood compartment of mice and demonstrate that mutant females develop a highly aggressive myeloproliferative neoplasm and myelodysplastic syndrome (mixed MPN/MDS) with 100% penetrance. Significant disease components include primary myelofibrosis, leukemia, histiocytic sarcoma, and vasculitis. Xist-deficient hematopoietic stem cells (HSC) show aberrant maturation and age-dependent loss. Reconstitution experiments indicate that MPN/MDS and myelofibrosis are of hematopoietic rather than stromal origin. We propose that Xist loss results in X-reactivation and consequent genome-wide changes that lead to cancer, thereby causally linking the X-chromosome to cancer in mice. Thus, Xist RNA is not only required to maintain XCI but also suppresses cancer in vivo.
Xist RNA is a potent suppressor of hematologic cancer in mice.
Sex, Age, Specimen part
View SamplesTranscriptional profiling of mouse mesenchymal stem/progenitor cells (MSPC) comparing control Ptpn11+/+ MSPC with Ptpn11E76K/+ MSPC. By obtaining 20 million reads of sequence from two pair, we confirmed our cytokine/chemokine array data and quantitative ELISA data from both mouse and patient-derived specimens. CCL3, CCL12, CCL4, and CXCL12 (SDF-1) were aberrantly produced by Ptpn11 mutated MSPCs Overall design: Examination of mouse Ptpn11E76K/+ mesenchymal stem/progenitor cells (MSPC) transcriptional profiling compared to control Ptpn11+/+ MSPC, freshly isolated from Ptpn11E76K/+/Nestin and Ptpn11+/+/Nestin mice. Two replicate per array.
Leukaemogenic effects of Ptpn11 activating mutations in the stem cell microenvironment.
Specimen part, Cell line, Subject
View SamplesMonocytes are derived from hematopoietic stem cells through a series of intermediate progenitor stages, but the factors that regulate this process are incompletely defined. Using a Ccr2/Cx3cr1 dual-reporter system to model murine monocyte ontogeny, we conducted a small molecule screen that identified an essential role of mechanistic target of rapamycin complex 1 (mTORC1) in the development of monocytes and other myeloid cells. Overall design: Examination of gene expression in 1) Granulocyte-Monocyte Progenitors from Raptor KO mice, Tsc2 KO mice and controls; and 2) DR-ER-Hoxb8 cells differentiated in the presence of DMSO, rapamycin or SL0101-01
The metabolic regulator mTORC1 controls terminal myeloid differentiation.
Specimen part, Cell line, Subject
View SamplesWe performed gene expression microarray comparing Osx-mCherry cells and Ocn-Topaz cells isolated from the OsxCre-mCherry;OcnCre-Topaz double transgenic mice by flow cytometry.
Specific bone cells produce DLL4 to generate thymus-seeding progenitors from bone marrow.
Specimen part
View SamplesWe investigated the role of mTORC1 in murine hematopoiesis by conditionally deleting the Raptor gene in murine hematopoietic stem cells. We observed mutliple alterations evoked by Raptor loss in hematopoiesis and profiled gene-expression alterations induced by raptor loss in Flt3-Lin-Sca1+cKit+ hematopoietic stem and progenitor enriched cell populations, 5 weeks post Raptor deletion.
mTOR complex 1 plays critical roles in hematopoiesis and Pten-loss-evoked leukemogenesis.
Specimen part
View SamplesThe ADAR RNA editing enzymes deaminate adenosine bases to inosines in cellular RNAs, recoding open reading frames. Human ADAR1 mutations cause Aicardi-Goutieres Syndrome (AGS) and Adar1 mutant mice showing an aberrant interferon response and death by embryonic day E12.5 model the human disease. Searches have not identified key ADAR1 RNA editing sites recoding immune/haematopoietic proteins but editing is widespread in Alu sequences. We show that Adar1 embryonic lethality is rescued in Adar1; Mavs double mutant mice in which general antiviral responses to cytoplasmic dsRNA are prevented. We propose that inosine bases are epigenetic marks identifying cellular RNA as innate immune ÒselfÓ. Consistent with this idea we show that an editing-active cytoplasmic ADAR is required to prevent aberrant immune responses in Adar1 mutant mouse embryo fibroblasts. No dramatic increase in repetitive transcripts is observed. AGS mutations in ADAR1 affect editing by the interferon-inducible cytoplasmic ADAR1 isoform. Overall design: RNA-seq expression profiling in Adar1 and Adar1/Mavs knockout mice embryos.
The RNA-editing enzyme ADAR1 controls innate immune responses to RNA.
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View SamplesMutation or epigenetic silencing of the transcription factor C/EBP is observed in ~10% of patients with acute myeloid leukemia (AML). In both cases, a common global gene expression profile is observed, but down-stream targets relevant for leukemogenesis are not known. Here we identify Sox4 as a direct target of C/EBP whereby its expression is inversely correlated with C/EBP activity. Downregulation of Sox4 abrogated increased self-renewal of leukemic cells and restored their differentiation. Gene expression profiles of leukemia initiating cells (LICs) from both Sox4 overexpression and murine mutant C/EBP AML models clustered together, but differed from other types of AML. Our data demonstrate that Sox4 overexpression resulting from C/EBP inactivation contributes to the development of leukemias with a distinct LIC phenotype.
Sox4 is a key oncogenic target in C/EBPα mutant acute myeloid leukemia.
Specimen part
View SamplesTransplantation with low numbers of hematopoietic stem cells (HSCs), found in many of the publically accessible cryopreserved umbilical cord blood (UCB) units, leads to delayed time to engraftment, high graft failure rates, and early mortality in many patients. A chemical screen in zebrafish identified the prostaglandin compound, 16,16 dimethyl prostaglandin E2 (dmPGE2), to be a critical regulator of hematopoietic stem cell homeostasis. We hypothesized that an ex vivo modulation with dmPGE2 prior to transplantation would lead to enhanced engraftment by increasing the effective dose of hematopoietic stem cells (HSCs) in cord blood. A phase I trial of reduced-intensity double UCB transplantation was performed to evaluate safety, rates of engraftment and fractional chimerism of dmPGE2 enhanced UCB units. To explore potential causes of the lack of enhanced efficacy in the first cohort, we characterized HSCs to determine whether the prostaglandin pathway was being activated under the ex vivo incubation conditions (4C, 10M dmPGE2, 60 minutes). Incubation conditions were identified (37C, 10M dmPGE2, 120 minutes) that maximize the activation of the prostaglandin pathway by dmPGE2 in human CD34+ cells.
Prostaglandin-modulated umbilical cord blood hematopoietic stem cell transplantation.
Specimen part, Treatment
View SamplesUmbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) for use in allogeneic transplantation. Key advantages of UCB are rapid availability and less stringent requirements for HLA matching. However, UCB contains an inherently limited HSC count, which is associated with delayed time to engraftment, high graft failure rates and early mortality. 16,16 dimethyl prostaglandin E2 (dmPGE2) was previously identified to be a critical regulator of HSC homeostasis and we hypothesized that a brief ex vivo modulation could improve patient outcomes by increasing the effective dose of HSCs.
Prostaglandin-modulated umbilical cord blood hematopoietic stem cell transplantation.
Specimen part
View SamplesUmbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) for use in allogeneic transplantation. Key advantages of UCB are rapid availability and less stringent requirements for HLA matching. However, UCB contains an inherently limited HSC count, which is associated with delayed time to engraftment, high graft failure rates and early mortality. 16,16 dimethyl prostaglandin E2 (dmPGE2) was previously identified to be a critical regulator of HSC homeostasis and we hypothesized that a brief ex vivo modulation could improve patient outcomes by increasing the "effective dose" of HSCs.
Prostaglandin-modulated umbilical cord blood hematopoietic stem cell transplantation.
Specimen part, Treatment
View Samples