| 1. |
- Adewumi, Oluseun, et al.
(författare)
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Characterization of human embryonic stem cell lines by the International Stem Cell Initiative
- 2007
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Ingår i: Nature Biotechnology. - : Springer Science and Business Media LLC. - 1087-0156 .- 1546-1696. ; 25:7, s. 803-816
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Tidskriftsartikel (refereegranskat)abstract
- The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue- nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allele-specific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.
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| 2. |
- Noaksson, K, et al.
(författare)
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Monitoring differentiation of human embryonic stem cells using real-time PCR
- 2005
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Ingår i: Stem Cells. - : Oxford University Press (OUP). - 1549-4918 .- 1066-5099. ; 23:10, s. 1460-1467
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Tidskriftsartikel (refereegranskat)abstract
- There is a general lack of rapid, sensitive, and quantitative methods for the detection of differentiating human embryonic stem cells (hESCs). Using light microscopy and immunohistochemistry, we observed that morphological changes of differentiating hESCs precede any major alterations in the expression of several commonly used hESC markers (SSEA-3, SSEA-4, TRA-1-60, TRA-1-81, Oct-4, and Nanog). In an attempt to quantify the changes during stochastic differentiation of hESCs, we developed a robust and sensitive multimarker quantitative real-time polymerase chain reaction (QPCR) method. To maximize the sensitivity of the method, we measured the expression of up- and downregulated genes before and after differentiation of the hESCs. Out of the 12 genes assayed, we found it clearly sufficient to determine the relative differentiation state of the cells by calculating a collective expression index based on the mRNA levels of Oct-4, Nanog, Cripto, and (x-fetoprotein. We evaluated the method using different hESC lines maintained in either feeder-dependent or feeder-free culture conditions. The QPCR method is very flexible, and by appropriately selecting reporter genes, the method can be designed for various applications. The combination of QPCR with hESC-based technologies opens novel avenues for high-throughput analysis of hESCs in, for example, pharmacological and cytotoxicity screening. STEM CELLS 2005;23:1460-1467.
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| 3. |
- Sartipy, P., et al.
(författare)
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Regulation of 'stemness' and stem cell differentiation by microRNAs
- 2009
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Ingår i: IDrugs. The Investigational Drugs Journal. - : BioMed Central. - 1369-7056 .- 2040-3410. ; 12:8, s. 492-496
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Forskningsöversikt (refereegranskat)abstract
- Pluripotency and cellular differentiation are intricate biological processes that are coordinately regulated by a complex set of factors and epigenetic regulators. Human pluripotent stem cell lines can be generated from surplus fertilized eggs or, as demonstrated more recently, from the reprogramming of somatic cells. Standardized culture conditions for the long-term maintenance and propagation of undifferentiated human pluripotent stem cells have also been developed. An objective of current research is to increase the understanding of the molecular mechanisms that regulate stem cell differentiation. The differentiation of human pluripotent stem cells may enable the generation of large quantities of specialized cells that can be used as in vitro tools for drug development, as well as for future applications in regenerative medicine. However, most of the currently used differentiation protocols yield inefficient stem cell quantities and low purity of the final cell preparations. The discovery of microRNAs (miRNAs) and their role as important transcriptional regulators may provide a new means of manipulating stem cell fate. This article provides an overview of some recent advancements made in the fields of both stem cell biology and miRNA.
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