Generation of human-induced pluripotent stem cells from gut mesentery-derived cells by ectopic expression of OCT4/SOX2/NANOG.
ABSTRACT Induced pluripotent stem (iPS) cells have been generated from human somatic cells by ectopic expression of defined transcription factors. Application of this approach in human cells may have enormous potential to generate patient-specific pluripotent stem cells. However, traditional methods of reprogramming in human somatic cells involve the use of oncogenes c-MYC and KLF4, which are not applicable to clinical translation. In the present study, we investigated whether human fetal gut mesentery-derived cells (hGMDCs) could be successfully reprogrammed into induced pluripotent stem (iPS) cells by OCT4, SOX2, and NANOG alone. We used lentiviruses to express OCT4, SOX2, NANOG, in hGMDCs, then generated iPS cells that were identified by morphology, presence of pluripotency markers, global gene expression profile, DNA methylation status, capacity to form embryoid bodies (EBs), and terotoma formation. iPS cells resulting from hGMDCs were similar to human embryonic stem (ES) cells in morphology, proliferation, surface markers, gene expression, and epigenetic status of pluripotent cell-specific genes. Furthermore, these cells were able to differentiate into cell types of all three germ layers both in vitro and in vivo, as shown by EB and teratoma formation assays. DNA fingerprinting showed that the human iPS cells were derived from the donor cells, and are not a result of contamination. Our results provide proof that hGMDCs can be reprogrammed into pluripotent cells by ectopic expression of three factors (OCT4, SOX2, and NANOG) without the use of oncogenes c-MYC and KLF4.
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- "EXPRESSION DURING LIMB REGENERATION Limb regeneration in Xenopus involves numerous signaling pathways (Beck et al., 2009), including BMP (Beck et al., 2006), Fgf (Yokoyama et al., 2000), and Wnt (Kawakami et al., 2006). Regulation of Sall4 expression during reprogramming and maintenance of pluripotency in ESC and somatic stem cells and probably during patterning also involves numerous context-dependent signaling pathways (Li et al., 2010). For example, in Drosophila melanogaster spalt/Sal expression is regulated during embryogenesis by Shh, dpp (BMP), and EGF signaling pathways, depending on the context (de Celis and Barrio, 2009). "
ABSTRACT: A central feature of epimorphic regeneration during amphibian limb regeneration is cellular dedifferentiation. Two questions are discussed. First, what is the origin and nature of the soluble factors involved in triggering local cellular and tissue dedifferentiation? Secondly, what role does the key stem cell transcription factor Sall4 play in reprogramming gene expression during dedifferentiation? The pattern of Sall4 expression during Xenopus hindlimb regeneration is consistent with the hypothesis that Sall4 plays a role in dedifferentiation (reprogramming) and in maintaining limb blastema cells in an undifferentiated state. Sall4 is involved in maintenance of ESC pluripotency, is a major repressor of differentiation, plays a major role in reprogramming differentiated cells into iPSCs, and is a component of the stemness regulatory circuit of pluripotent ESCs and iPSCs. These functions suggest Sall4 as an excellent candidate to regulate reprogramming events that produce and maintain dedifferentiated blastema cells required for epimorphic regeneration.Developmental Dynamics 05/2011; 240(5):979-89. DOI:10.1002/dvdy.22554 · 2.67 Impact Factor
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ABSTRACT: Animal embryonic stem cells (ESCs) provide powerful tool for studies of early embryonic development, gene targeting, cloning, and regenerative medicine. However, the majority of attempts to establish ESC lines from large animals, especially ungulate mammals have failed. Recently, another type of pluripotent stem cells, known as induced pluripotent stem cells (iPSCs), have been successfully generated from mouse, human, monkey, rat and pig. In this study we show sheep fibroblasts can be reprogrammed to pluripotency by defined factors using a drug-inducible system. Sheep iPSCs derived in this fashion have a normal karyotype, exhibit morphological features similar to those of human ESCs and express AP, Oct4, Sox2, Nanog and the cell surface marker SSEA-4. Pluripotency of these cells was further confirmed by embryoid body (EB) and teratoma formation assays which generated derivatives of all three germ layers. Our results also show that the substitution of knockout serum replacement (KSR) with fetal bovine serum in culture improves the reprogramming efficiency of sheep iPSCs. Generation of sheep iPSCs places sheep on the front lines of large animal preclinical trials and experiments involving modification of animal genomes.PLoS ONE 01/2011; 6(1):e15947. DOI:10.1371/journal.pone.0015947 · 3.53 Impact Factor
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ABSTRACT: Induced pluripotent stem (iPS) cells, obtained from reprogramming somatic cells by ectopic expression of a defined set of transcription factors or chemicals, are expected to be used as differentiated cells for drug screening or evaluations of drug toxicity and cell replacement therapies. As pluripotent stem cells, iPS cells are similar to embryonic stem (ES) cells in morphology and marker expression. Several types of iPS cells have been generated using combinations of reprogramming molecules and/or small chemical compounds from different types of tissues. A comprehensive approach, such as global gene or microRNA expression analysis and whole genomic DNA methylation profiling, has demonstrated that iPS cells are similar to their embryonic counterparts. Considering the substantial variation among iPS cell lines reported to date, the safety and therapeutic implications of these differences should be thoroughly evaluated before they are used in cell therapies. Here, we review recent research defining the concept of standardization for iPS cells, their ability to differentiate and the identity of the differentiated cells.Stem Cell Research & Therapy 03/2012; 3(2):8. DOI:10.1186/scrt99 · 4.63 Impact Factor