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  • ESGRO® Mouse LIF Medium -ESG1106

    Document Type:
    Certificate of Analysis
    Lot Number:
    ESG1106
    Product Catalog Number:
    ESG1106
    Product Catalog Name:
    ESGRO® Recombinant Mouse LIF Protein
  • Karyotyping ES Cells

    Document Type:
    Protocols
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Using small molecules to improve generation of induced pluripotent stem cells from somatic cells 20336525

    Induction of pluripotent stem cells from somatic cells by defined factors was shown to be possible only recently, but already several laboratories have made tremendous strive toward improving and understanding the process. Originally, Oct4, Sox2, Klf4, and cMyc were identified as being the combination of genes necessary to induce reprogramming. It was later shown that cMyc was dispensable; however, in its absence the process was less efficient and took a considerably longer period of time to occur. Furthermore, others have shown that the combination of Oct4, Sox2, Nanog, and Lin28 could also induce reprogramming. One major caveat associated with these techniques remains the need for overexpression of several genes using viral systems. Until very recently, most studies were done using integrating viruses such as retroviruses and lentiviruses. This method ensured that the protein of interested would be expressed at a high concentration and for an adequate period of time necessary to induce reprogramming. Up to date, others have now been able to use different nonintegrative method such as adenovirus and plasmid transfection to induce reprogramming. Furthermore, piggyBac transposition was successfully used to induce reprogramming of murine cells. Most importantly, it was recently published that reprogramming can be induced in the absence of virus, with proteins and small molecules. All of the later methods are appealing since they do not require the integration of the virus or plasmid to exert its effect. However, one avenue that would be all the more therapeutically appealing would be to induce reprogramming in the absence of gene overexpression systems, using small molecules to modulate signaling pathways in the somatic cells. A few molecules have already been identified with the ability to either improve the process or replace one or two of the genes deemed necessary for reprogramming. We have screened successfully for compounds that can replace some of these factors, and share the methods developed following these screens.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Derivation of mouse embryonic stem cells 17487198

    Here we describe a simple and efficient protocol for derivation of germline chimera-competent mouse embryonic stem cells (mESCs) from embryonic day 3.5 (E3.5) blastocysts. The protocol involves the use of early-passage mouse embryonic fibroblast feeders (MEF) and the alternation of fetal bovine serum- and serum replacement (SR)-containing media. As compared to other available protocols for mESCs derivation, our protocol differs in the combination of commercial availability of all reagents, technical simplicity and high efficiency. mESC lines are derived with approximately 50% efficiency (50 independent mESC lines derived from 96 blastocysts). We believe that this protocol could be a good starting point for (i) setting up the derivation of mESC lines in a laboratory and (ii) incorporating further steps to improve efficiency or adapt the protocol to other applications. The whole process (from blastocyst extraction to the freezing of mESC line) usually takes between 15 and 20 d.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Dynamic regulation of 5-hydroxymethylcytosine in mouse ES cells and during differentiation. 21460836

    Methylation at the 5' position of cytosine in DNA has important roles in genome function and is dynamically reprogrammed during early embryonic and germ cell development. The mammalian genome also contains 5-hydroxymethylcytosine (5hmC), which seems to be generated by oxidation of 5-methylcytosine (5mC) by the TET family of enzymes that are highly expressed in embryonic stem (ES) cells. Here we use antibodies against 5hmC and 5mC together with high throughput sequencing to determine genome-wide patterns of methylation and hydroxymethylation in mouse wild-type and mutant ES cells and differentiating embryoid bodies. We find that 5hmC is mostly associated with euchromatin and that whereas 5mC is under-represented at gene promoters and CpG islands, 5hmC is enriched and is associated with increased transcriptional levels. Most, if not all, 5hmC in the genome depends on pre-existing 5mC and the balance between these two modifications is different between genomic regions. Knockdown of Tet1 and Tet2 causes downregulation of a group of genes that includes pluripotency-related genes (including Esrrb, Prdm14, Dppa3, Klf2, Tcl1 and Zfp42) and a concomitant increase in methylation of their promoters, together with an increased propensity of ES cells for extraembryonic lineage differentiation. Declining levels of TETs during differentiation are associated with decreased hydroxymethylation levels at the promoters of ES cell-specific genes together with increased methylation and gene silencing. We propose that the balance between hydroxymethylation and methylation in the genome is inextricably linked with the balance between pluripotency and lineage commitment.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Enforced activation of STAT5A facilitates the generation of embryonic stem-derived hematopoietic stem cells that contribute to hematopoiesis in vivo. 15579639

    Little is known about the molecular mechanisms that direct the transition from primitive to definitive hematopoiesis. In this study, we cocultured murine embryonic stem (ES) cells on OP9 stroma to induce hematopoietic differentiation as a model to study factors involved in the generation of adult hematopoietic stem cells (HSCs). Overexpression of the constitutively activated mutant signal transducer and activator of transcription (STAT) 5A(1*6) in ES cells facilitated the generation of cells that expressed the endothelial-hemangioblast marker Flk-1 within 5 days of coculture on OP9. The first CD41+/ CD45+/c-Kit+/(Flk-1)- hematopoietic cells arose in our culture conditions between days 5 and 7. Persistent activation of STAT5A greatly enhanced the generation of hematopoietic progenitors compared with controls, as determined by colony assays in methylcellulose. Moreover, whereas controls generated only a short transient wave of hematopoiesis lasting less than 3 weeks, expression of STAT5A(1*6) resulted in the generation of hematopoietic cobblestone area-forming cells (CAFCs) on OP9 that could be serially passaged onto new OP9, giving rise to second and third CAFCs that generated hematopoietic progenitors for > or = 5 weeks, indicating a role for STAT5A in HSC self-renewal in vitro. Several definitive hematopoietic genes were upregulated by STAT5A (1*6), as well as Runx1/AML1, vascular endothelial growth factor, oncostatin M receptor, HoxB4, Wnt5A, Delta-like-1, and Bmi-1. Furthermore, ES-derived hematopoietic cells expressing STAT5A(1*6) contributed to myeloid-lymphoid hematopoiesis in primary and secondary nonobese diabetic-severe combined immunodeficiency recipients, although no donor-derived cells could be detected after 7 weeks in the secondary recipients. These data indicate that a persistent activation of STAT5A allows the generation of ES-derived HSCs that can, at least for an intermediate period, contribute to hematopoiesis in vivo.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Optimization of Protocols for Derivation of Mouse Embryonic Stem Cell Lines from Refractory Strains, Including the Non Obese Diabetic Mouse. 21933027

    The derivation of pluripotent embryonic stem cells (ESCs) from a variety of genetic backgrounds remains a desirable objective in the generation of mice functionally deficient in genes of interest and the modeling of human disease. Nevertheless, disparity in the ease with which different strains of mice yield ESC lines has long been acknowledged. Indeed, the generation of bona fide ESCs from the non obese diabetic (NOD) mouse, a well-characterized model of human type I diabetes, has historically proved especially difficult to achieve. Here, we report the development of protocols for the derivation of novel ESC lines from C57Bl/6 mice based on the combined use of high concentrations of leukemia inhibitory factor and serum-replacement, which is equally applicable to fresh and cryo-preserved embryos. Further, we demonstrate the success of this approach using Balb/K and CBA/Ca mice, widely considered to be refractory strains. CBA/Ca ESCs contributed to the somatic germ layers of chimeras and displayed a very high competence at germline transmission. Importantly, we were able to use the same protocol for the derivation of ESC lines from nonpermissive NOD mice. These ESCs displayed a normal karyotype that was robustly stable during long-term culture, were capable of forming teratomas in vivo and germline competent chimeras after injection into recipient blastocysts. Further, these novel ESC lines efficiently formed embryoid bodies in vitro and could be directed in their differentiation along the dendritic cell lineage, thus illustrating their potential application to the generation of cell types of relevance to the pathogenesis of type I diabetes.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple
  • Systematic delineation of optimal cytokine concentrations to expand hematopoietic stem/progenitor cells in co-culture with mesenchymal stem cells. 20424784

    The major obstacle to the widespread use of umbilical cord blood (UCB) in hematopoietic stem/progenitor (HSC) cell therapy is the low cell dose available. A cytokine cocktail for the ex vivo expansion of UCB HSC, in co-culture with a bone marrow (BM) mesenchymal stem cells (MSC)-derived stromal layer was optimized using an experimental design approach. Proliferation of total cells (TNC), stem/progenitor cells (CD34(+)) and colony-forming units (CFU) was assessed after 7 days in culture, while sole and interactive effects of each cytokine on HSC expansion were statistically determined using a two-level Face-Centered Cube Design. The optimal cytokine cocktail obtained for HSC-MSC co-cultures was composed by SCF, Flt-3L and TPO (60, 55 and 50 ng mL(-1), respectively), resulting in 33-fold expansion in TNC, 17-fold in CD34(+) cells, 3-fold in CD34(+)CD90(+) cells and 21-fold in CFU-MIX. More importantly, these short-term expanded cells preserved their telomere length and extensively generated cobblestone area-forming cells (CAFCs) in vitro. The statistical tools used herein contributed for the rational delineation of the cytokine concentration range, in a cost-effective way, while systematically addressing complex cytokine-to-cytokine interactions, for the efficient HSC expansion towards the generation of clinically significant cell numbers for transplantation.
    Document Type:
    Reference
    Product Catalog Number:
    Multiple
    Product Catalog Name:
    Multiple