Project description:This SuperSeries is composed of the following subset Series: GSE33953: Time-course transcriptome measure of HoxB4-mediated HSC development from ES cells GSE34013: Time-course HoxB4 ChIP-Seq during HSC development from ES cells Refer to individual Series
Project description:Efficient in vitro generation of hematopoietic stem cells (HSCs) from embryonic stem cells (ESCs) holds great promise for cell-based therapies of hematological diseases. To date, HoxB4 remains to be the most effective transcription factor (TF) whose over-expression in ESCs confers long-term repopulating ability to ESC-derived HSCs. Despite its importance, the components and dynamics of the HoxB4 transcriptional regulatory network is poorly understood, hindering efforts to develop a more efficient protocol for in vitro derivation of HSCs. Towards this goal, we performed global gene expression profiling and chromatin immunoprecipitation coupled with deep sequencing (ChIP-Seq) at four stages of the HoxB4-mediated HSC development. Joint analyses of ChIP-Seq and gene expression profiles unveil a number of global features of the HoxB4 regulatory network.
Project description:Efficient in vitro generation of hematopoietic stem cells (HSCs) from embryonic stem cells (ESCs) holds great promise for cell-based therapies of hematological diseases. To date, HoxB4 remains to be the most effective transcription factor (TF) whose over-expression in ESCs confers long-term repopulating ability to ESC-derived HSCs. Despite its importance, the components and dynamics of the HoxB4 transcriptional regulatory network is poorly understood, hindering efforts to develop a more efficient protocol for in vitro derivation of HSCs. Towards this goal, we performed global gene expression profiling and chromatin immunoprecipitation coupled with deep sequencing (ChIP-Seq) at four stages of the HoxB4-mediated HSC development. Joint analyses of ChIP-Seq and gene expression profiles unveil a number of global features of the HoxB4 regulatory network.
Project description:Efficient in vitro generation of hematopoietic stem cells (HSCs) from embryonic stem cells (ESCs) holds great promise for cell-based therapies of hematological diseases. To date, HoxB4 remains to be the most effective transcription factor (TF) whose over-expression in ESCs confers long-term repopulating ability to ESC-derived HSCs. Despite its importance, the components and dynamics of the HoxB4 transcriptional regulatory network is poorly understood, hindering efforts to develop a more efficient protocol for in vitro derivation of HSCs. Towards this goal, we performed global gene expression profiling and chromatin immunoprecipitation coupled with deep sequencing (ChIP-Seq) at four stages of the HoxB4-mediated HSC development. Joint analyses of ChIP-Seq and gene expression profiles unveil a number of global features of the HoxB4 regulatory network. Cells from three time points of the developmental processes were collected, including days 6, 16, and 26. Deep sequencing were done for both IP and input DNA from cells from each time point.
Project description:Efficient in vitro generation of hematopoietic stem cells (HSCs) from embryonic stem cells (ESCs) holds great promise for cell-based therapies of hematological diseases. To date, HoxB4 remains to be the most effective transcription factor (TF) whose over-expression in ESCs confers long-term repopulating ability to ESC-derived HSCs. Despite its importance, the components and dynamics of the HoxB4 transcriptional regulatory network is poorly understood, hindering efforts to develop a more efficient protocol for in vitro derivation of HSCs. Towards this goal, we performed global gene expression profiling and chromatin immunoprecipitation coupled with deep sequencing (ChIP-Seq) at four stages of the HoxB4-mediated HSC development. Joint analyses of ChIP-Seq and gene expression profiles unveil a number of global features of the HoxB4 regulatory network. Cells from four time points of the developmental processes were collected, including days 0, 6, 16, and 26. Triplicate microarray hybridizations were done for cells from each time point.
Project description:Overexpression of HOXB4 in hematopoietic stem cells (HSCs) leads to increased self-renewal without causing hematopoietic malignancies in transplanted mice. The molecular basis of HOXB4-mediated benign HSC expansion in vivo is not well understood. To gain further insight into the molecular events underlying HOXB4-mediated HSC expansion, we analyzed gene expression changes at multiple time points in Lin-Sca1+c-kit+ (LSK) cells from mice transplanted with bone marrow (BM) cells transduced with a MSCV-HOXB4-ires-YFP vector. A distinct HOXB4 transcriptional program was reproducibly induced and stabilized by 12 weeks after transplant. Dynamic expression changes were observed in genes critical for HSC self-renewal as well as genes involved in myeloid and B cell differentiation. Prdm16, a transcription factor associated with human acute myeloid leukemia (AML), was markedly repressed by HOXB4 but upregulated by HOXA9 and HOXA10, suggesting that Prdm16 downregulation was involved in preventing leukemia in HOXB4 transplanted mice. Functional evidence to support this mechanism was obtained by enforcing co-expression of sPrdm16 and HOXB4, which led to enhanced self-renewal, myeloid expansion, and leukemia. Altogether, these studies define the transcriptional pathways involved in HOXB4 HSC expansion in vivo and identify repression of Prdm16 transcription as a mechanism by which expanding HSCs avoid leukemic transformation.
Project description:Haematopoietic differentiation of embryonic stem (ES) cells in vitro has been used as a model to study early haematopoietic development and it is well documented that haematopoietic differentiation can be enhanced by over-expression of HOXB4. HOXB4 is expressed in haematopoietic progenitor cells (HPC) where it promotes self-renewal, but it is also expressed in the primitive streak of the gastrulating embryo. This led us to hypothesise that HOXB4 might modulate gene expression in pre- haematopoietic mesoderm and that this property might contribute to its pro-haematopoietic effect in differentiating ES cells. To test our hypothesis we developed a conditionally activated HOXB4 expression system using the mutant oestrogen receptor (ERT2) and showed that a pulse of HOXB4 prior to HPC emergence in differentiating ES cells led to an increase in haematopoietic differentiation. Expression profiling revealed an increase in the expression of genes associated with paraxial mesoderm that gives rise to the haematopoietic niche. Cell mixing experiments suggest that HOXB4 activation can indeed have a paracrine, as well as a cell autonomous, effect on haematopoietic differentiation. We provide evidence that this may, in part, be mediated by modulation of the Wnt pathway via the HOXB4 target gene, Frzb. Constructs: HOXB4-ERT2 constructs were generated that utilised the CAG promoter to drive expression of the Hoxb4ERT2 fusion cDNA followed by an IRES element and the puromycin resistance gene (pCAG Hoxb4ERT2IP); CGR8.5 cells bearing Hoxb4VP16 fusion construct. Fusion of HOXB4-ERT2 with the transactivation domain of the Herpes simplex VP16 (Brickman et al. 2000) (Zamparini et al. 2006) was generated by PCR as were 2 mutants: Hoxb4 (N266P)VP16/Pcs2+ and Hoxb4 (d266)VP16/Pcs2+ which had mutations in an asparagine (residue 266) in the third helix of the homeodomain which functions in DNA recognition (Hanes and Brent 1989).
Project description:Overexpression of HOXB4 in hematopoietic stem cells (HSCs) leads to increased self-renewal without causing hematopoietic malignancies in transplanted mice. The molecular basis of HOXB4-mediated benign HSC expansion in vivo is not well understood. To gain further insight into the molecular events underlying HOXB4-mediated HSC expansion, we analyzed gene expression changes at multiple time points in Lin-Sca1+c-kit+ (LSK) cells from mice transplanted with bone marrow (BM) cells transduced with a MSCV-HOXB4-ires-YFP vector. A distinct HOXB4 transcriptional program was reproducibly induced and stabilized by 12 weeks after transplant. Dynamic expression changes were observed in genes critical for HSC self-renewal as well as genes involved in myeloid and B cell differentiation. Prdm16, a transcription factor associated with human acute myeloid leukemia (AML), was markedly repressed by HOXB4 but upregulated by HOXA9 and HOXA10, suggesting that Prdm16 downregulation was involved in preventing leukemia in HOXB4 transplanted mice. Functional evidence to support this mechanism was obtained by enforcing co-expression of sPrdm16 and HOXB4, which led to enhanced self-renewal, myeloid expansion, and leukemia. Altogether, these studies define the transcriptional pathways involved in HOXB4 HSC expansion in vivo and identify repression of Prdm16 transcription as a mechanism by which expanding HSCs avoid leukemic transformation. 5-FU treated bone marrow cells from female C57Bl/6L mice were transduced with concentrated supernatant from GPE+86-derived producer cells containing MSCV-HOXB4-ires-YFP or MSCV-ires-GFP retroviral vectors. Transduced cells were transplanted into lethally irradiated C57Bl/6L mice. HOXB4-YFP or GFP expressing LSK cells were sorted from transplanted mice at 6, 12 and 24 weeks post transplantation, of which RNA was extracted for microarray.