A. Z. Zhu et al. (Jul 2024)
Stem Cell Research & Therapy 15 6
HES1 is required for mouse fetal hematopoiesis
Hematopoiesis in mammal is a complex and highly regulated process in which hematopoietic stem cells (HSCs) give rise to all types of differentiated blood cells. Previous studies have shown that hairy and enhancer of split (HES) repressors are essential regulators of adult HSC development downstream of Notch signaling. In this study,we investigated the role of HES1,a member of HES family,in fetal hematopoiesis using an embryonic hematopoietic specific Hes1 conditional knockout mouse model by using phenotypic flow cytometry,histopathology analysis,and functional in vitro colony forming unit (CFU) assay and in vivo bone marrow transplant (BMT) assay. We found that loss of Hes1 in early embryonic stage leads to smaller embryos and fetal livers,decreases hematopoietic stem progenitor cell (HSPC) pool,results in defective multi-lineage differentiation. Functionally,fetal hematopoietic cells deficient for Hes1 exhibit reduced in vitro progenitor activity and compromised in vivo repopulation capacity in the transplanted recipients. Further analysis shows that fetal hematopoiesis defects in Hes1 fl/fl Flt3Cre embryos are resulted from decreased proliferation and elevated apoptosis,associated with de-repressed HES1 targets,p27 and PTEN in Hes1 -KO fetal HSPCs. Finally,pharmacological inhibition of p27 or PTEN improves fetal HSPCs function both in vitro and in vivo. Together,our findings reveal a previously unappreciated role for HES1 in regulating fetal hematopoiesis,and provide new insight into the differences between fetal and adult HSC maintenance. The online version contains supplementary material available at 10.1186/s13287-024-03836-8.
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Ibarra I et al. (DEC 2007)
Genes & development 21 24 3238--43
A role for microRNAs in maintenance of mouse mammary epithelial progenitor cells.
microRNA (miRNA) expression profiles are often characteristic of specific cell types. The mouse mammary epithelial cell line,Comma-Dbeta,contains a population of self-renewing progenitor cells that can reconstitute the mammary gland. We purified this population and determined its miRNA signature. Several microRNAs,including miR-205 and miR-22,are highly expressed in mammary progenitor cells,while others,including let-7 and miR-93,are depleted. Let-7 sensors can be used to prospectively enrich self-renewing populations,and enforced let-7 expression induces loss of self-renewing cells from mixed cultures.
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A 3D sphere culture system containing functional polymers for large-scale human pluripotent stem cell production
Utilizing human pluripotent stem cells (hPSCs) in cell-based therapy and drug discovery requires large-scale cell production. However,scaling up conventional adherent cultures presents challenges of maintaining a uniform high quality at low cost. In this regard,suspension cultures are a viable alternative,because they are scalable and do not require adhesion surfaces. 3D culture systems such as bioreactors can be exploited for large-scale production. However,the limitations of current suspension culture methods include spontaneous fusion between cell aggregates and suboptimal passaging methods by dissociation and reaggregation. 3D culture systems that dynamically stir carrier beads or cell aggregates should be refined to reduce shearing forces that damage hPSCs. Here,we report a simple 3D sphere culture system that incorporates mechanical passaging and functional polymers. This setup resolves major problems associated with suspension culture methods and dynamic stirring systems and may be optimal for applications involving large-scale hPSC production. ?? 2014 The Authors.
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产品类型：
产品号#：
85850
85857
产品名：
mTeSR™1
mTeSR™1
N. Kriedemann et al. (Jul 2024)
Stem Cell Research & Therapy 15
Protein-free media for cardiac differentiation of hPSCs in 2000 mL suspension culture
Commonly used media for the differentiation of human pluripotent stem cells into cardiomyocytes (hPSC-CMs) contain high concentrations of proteins,in particular albumin,which is prone to quality variations and presents a substantial cost factor,hampering the clinical translation of in vitro-generated cardiomyocytes for heart repair. To overcome these limitations,we have developed chemically defined,entirely protein-free media based on RPMI,supplemented with L-ascorbic acid 2-phosphate (AA-2P) and either the non-ionic surfactant Pluronic F-68 or a specific polyvinyl alcohol (PVA). Both media compositions enable the efficient,directed differentiation of embryonic and induced hPSCs,matching the cell yields and cardiomyocyte purity ranging from 85 to 99% achieved with the widely used protein-based CDM3 medium. The protein-free differentiation approach was readily up-scaled to a 2000 mL process scale in a fully controlled stirred tank bioreactor in suspension culture,producing > 1.3 × 10 9 cardiomyocytes in a single process run. Transcriptome analysis,flow cytometry,electrophysiology,and contractile force measurements revealed that the mass-produced cardiomyocytes differentiated in protein-free medium exhibit the expected ventricular-like properties equivalent to the well-established characteristics of CDM3-control cells. This study promotes the robustness and upscaling of the cardiomyogenic differentiation process,substantially reduces media costs,and provides an important step toward the clinical translation of hPSC-CMs for heart regeneration. The online version contains supplementary material available at 10.1186/s13287-024-03826-w.
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产品类型：
产品号#：
05025
产品名：
STEMdiff™心肌细胞分离试剂盒
Wognum AW et al. (OCT 1990)
Blood 76 7 1323--9
A specific in vitro bioassay for measuring erythropoietin levels in human serum and plasma.
The accurate measurement of biologically active erythropoietin (Ep) in human serum and plasma using present in vivo and in vitro bioassays is difficult because of the presence of both inhibitors and non-Ep stimulators of erythropoiesis. We have developed a simple procedure to quantitatively purify Ep from serum and plasma for subsequent testing in the phenylhydrazine-treated mouse spleen cell assay. The method involves absorption of Ep to an immobilized high-affinity anti-Ep monoclonal antibody and acid elution of the antibody-bound material. After neutralization,the eluted EP is then tested directly in the in vitro bioassay without interference by other serum proteins. By using magnetic beads as a solid support for the antibody,washing and elution steps can be performed rapidly and efficiently. Recoveries of Ep after this procedure show very little sample-to-sample variation and are consistently between 45% and 55%,which is close to the maximum binding expected for the anti-Ep antibody. Coupled with the 7.4-fold concentration that this procedure affords,there is an overall increase in sensitivity of three- to fourfold,which makes this assay suitable for accurately measuring Ep levels in patients with below-average titers. Results with this magnetic bead assay indicate that accurate and reproducible estimates for Ep levels in the serum and plasma from healthy donors as well as from patients with hematologic disorders can be obtained. Titers of biologically active Ep in the sera from a group of patients with either leukemia or lymphoma were found to be elevated,and the values correlated well with titers of immunoreactive Ep measured in the Ep radioimmunoassay. Because of its specificity and high sensitivity,the magnetic bead assay is a valuable alternative to immunoassays for the measurement of elevated,normal,and even subnormal Ep levels in human serum and plasma.
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产品类型：
产品号#：
01630
产品名：
Erythropoietin (EPO) ELISA试剂盒
Hawley RG et al. (JAN 2006)
Methods in enzymology 419 149--79
Hematopoietic stem cells.
Hematopoietic stem cells (HSCs) have the capacity to self-renew and the potential to differentiate into all of the mature blood cell types. The ability to prospectively identify and isolate HSCs has been the subject of extensive investigation since the first transplantation studies implying their existence almost 50 years ago. Despite significant advances in enrichment protocols,the continuous in vitro propagation of human HSCs has not yet been achieved. This chapter describes current procedures used to phenotypically and functionally characterize candidate human HSCs and initial efforts to derive permanent human HSC lines.
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Eminli S et al. (SEP 2009)
Nature genetics 41 9 968--76
Differentiation stage determines potential of hematopoietic cells for reprogramming into induced pluripotent stem cells.
The reprogramming of somatic cells into induced pluripotent stem (iPS) cells upon overexpression of the transcription factors Oct4,Sox2,Klf4 and cMyc is inefficient. It has been assumed that the somatic differentiation state provides a barrier for efficient reprogramming; however,direct evidence for this notion is lacking. Here,we tested the potential of mouse hematopoietic cells at different stages of differentiation to be reprogrammed into iPS cells. We show that hematopoietic stem and progenitor cells give rise to iPS cells up to 300 times more efficiently than terminally differentiated B and T cells do,yielding reprogramming efficiencies of up to 28%. Our data provide evidence that the differentiation stage of the starting cell has a critical influence on the efficiency of reprogramming into iPS cells. Moreover,we identify hematopoietic progenitors as an attractive cell type for applications of iPS cell technology in research and therapy.
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EasySep™小鼠TIL（CD45）正选试剂盒
技术手册Human Colony-Forming Unit (CFU) Assays Using MethoCult™
科学海报Optimized Media and Workflow for the Expansion of Human Pluripotent Stem Cells as Aggregates in Suspension Cultures
实验方案Transitioning from Feeder-Free Media to mTeSR™ Plus for Human Pluripotent Stem Cell Culture
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