Project description:An immortalized multipotent otic progenitor (iMOP) cell was generated by transient expression of c-Myc in Sox2-expressing otic progenitor cells. The procedure activated endogenous c-Myc expression in the cells and amplified existing Sox2-dependent transcripts to promote self-renewal. Downregulation of c-Myc expression following growth factor withdrawal resulted in a molecular switch from self-renewal to otic differentiation. Progenitor cells from embryonic inner ear that form otospheres were infected with a c-Myc retrovirus to promote self-renewal
Project description:An immortalized multipotent otic progenitor (iMOP) cell was generated by transient expression of c-Myc in Sox2-expressing otic progenitor cells. The procedure activated endogenous c-Myc expression in the cells and amplified existing Sox2-dependent transcripts to promote self-renewal. Downregulation of c-Myc expression following growth factor withdrawal resulted in a molecular switch from self-renewal to otic differentiation. ChIP-Seq was accomplished by immunoprecipitating endogenous RNA PolII, c-Myc and Sox2
Project description:An immortalized multipotent otic progenitor (iMOP) cell was generated by transient expression of c-Myc in Sox2-expressing otic progenitor cells. The procedure activated endogenous c-Myc expression in the cells and amplified existing Sox2-dependent transcripts to promote self-renewal. Downregulation of c-Myc expression following growth factor withdrawal resulted in a molecular switch from self-renewal to otic differentiation.
Project description:An immortalized multipotent otic progenitor (iMOP) cell was generated by transient expression of c-Myc in Sox2-expressing otic progenitor cells. The procedure activated endogenous c-Myc expression in the cells and amplified existing Sox2-dependent transcripts to promote self-renewal. Downregulation of c-Myc expression following growth factor withdrawal resulted in a molecular switch from self-renewal to otic differentiation.
Project description:The overexpression of transcription factors Oct4, Sox2, Klf4, and c-Myc reprograms a somatic nucleus to one that is transcriptionally and epigenetically indistinguishable from an embryonic stem (ES) cell. However, it is still unclear if transcription factors can completely convert the nucleus of a differentiated cell into that of a distantly related cell type such that it maintains complete transcriptional and epigenetic reprogramming in the absence of exogenous factor expression. To test this idea, we screened a library of doxycycline-inducible vectors encoding neural stem cell (NSC)-expressed genes and found that stable, self-maintaining NSC-like cells could be induced under defined growth conditions after transduction of transcription factors. These induced NSCs (iNSCs) were characterized in the absence of exogenous factor induction and were shown to be transcriptionally, epigenetically, and functionally similar to endogenous embryonic cortical NSCs. Importantly, iNSCs could be generated from multiple adult cell types including liver cells and B-cells with genetic rearrangements. Our results show that self-maintaining proliferative neural cells can be induced from non-ectodermal cells by expressing specific combinations of transcription factors. ChIP-seq data from primary neural progenitor cells (Sox2-GFP) and induced neural progenitor cells were generated by deep sequencing using Illumina Hi-Seq 2000.
Project description:Coordinate expression of the somatic cell reprogramming factors Oct4, Sox2, Klf4 and c-Myc within embryonic stem cells preserves the self-renewal of these cells, while allowing for the expression epitope tagged Sox2. Taking advantage of this observation, we engineered embryonic stem cells (i-OSKM-ESC) to inducibly express Oct4, Klf4, c-Myc and an epitope tagged form of Sox2 from a polycistronic element, in the presence of doxycycline. We isolated Sox2 and its associated protein complexes by co-immunoprecipitation. Subsequently, we identified the Sox2-protein interactome in self-renewing embryonic stem cells using an unbiased proteomic screen (Multidimensional Protein Identification Technology [MudPIT]). Affymetrix microarrays were used to characterize the gene expression profile of i-OSKM-ESC in the absence and presence of doxycycline. Mouse embryonic stem cells (KH2) were engineered to express Oct4, epitope tagged Sox2, Klf4 and c-Myc in the presence of doxycyline, to produce i-OSKM-ESC. The i-OSKM-ESC were cultured in the absence or presence of doxycyline (4 µg/mL) for 24 hours. RNA was extracted from each condition, and used for microarray analysis.
Project description:Hematopoietic stem cells (HSC) possess life-long self-renewal activity and generate a series of multipotent progenitors that differentiate into lineage-committed progenitors and subsequently mature cells. Recently, functionally distinct stem and progenitor cell types have been identified, however, a systems-wide understanding of the underlying gene regulation is lacking. Here, we present the global transcriptome of ex vivo isolated mouse multipotent hematopoietic stem/progenitor cells (HSPCs, LinnegSca-1+c-Kit+) and myeloid committed precursors (LinnegSca-1-c-Kit+) as revealed by next-generation sequencing (RNA-seq).
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.
