Project description:Human artificial chromosomes (HACs) have unique characteristics as gene-delivery vector, e.g., episomal transmission and transfer of multiple, large transgenes. Here, we demonstrate the advantages of HAC vectors for reprogramming mouse embryonic fibroblasts (MEFs) to induced pluripotent stem (iPS) cells. Two HAC vectors (iHAC1 and iHAC2) were constructed. Both carried four reprogramming factors, and iHAC2 also encoded a p53-knockdown construct (see Kazuki et al 2011). The iHAC1 partially reprogrammed MEFs, and the iHAC2 efficiently reprogrammed MEFs. Global gene expression showed that the iHACs, unlike other vectors, generated relatively uniform iPS cells. We established iHAC-free iPS cells by isolating cells that spontaneously lost the iHAC2. Analyses of pluripotent markers, teratomas, and chimeras confirmed that these iHAC-free iPS cells were pluripotent. Moreover, iHAC-free iPS cells with a re-introduced HAC encoding Herpes Simplex Virus Thymidine Kinase were eliminated by Ganciclovir treatment; therefore, the HAC safeguard system functioned in iPS cells. Thus, the HAC vector could generate uniform, integration-free iPS cells with a safeguard system.
Project description:Human artificial chromosomes (HACs) have unique characteristics as gene-delivery vector, e.g., episomal transmission and transfer of multiple, large transgenes. Here, we demonstrate the advantages of HAC vectors for reprogramming mouse embryonic fibroblasts (MEFs) to induced pluripotent stem (iPS) cells. Two HAC vectors (iHAC1 and iHAC2) were constructed. Both carried four reprogramming factors, and iHAC2 also encoded a p53-knockdown construct (see Kazuki et al 2011). The iHAC1 partially reprogrammed MEFs, and the iHAC2 efficiently reprogrammed MEFs. Global gene expression showed that the iHACs, unlike other vectors, generated relatively uniform iPS cells. We established iHAC-free iPS cells by isolating cells that spontaneously lost the iHAC2. Analyses of pluripotent markers, teratomas, and chimeras confirmed that these iHAC-free iPS cells were pluripotent. Moreover, iHAC-free iPS cells with a re-introduced HAC encoding Herpes Simplex Virus Thymidine Kinase were eliminated by Ganciclovir treatment; therefore, the HAC safeguard system functioned in iPS cells. Thus, the HAC vector could generate uniform, integration-free iPS cells with a safeguard system. Total RNA from mouse embryonic fibroblasts, two control ES cells (TT2 and B6ES), retrovirus vector-derived iPS cells (20D17), and twelve HAC-derived iPS clones were hybridized to the Agilent Whole Mouse Genome microarrays.
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells. This SuperSeries is composed of the following subset Series:; GSE15175: Human induced pluripotent stem cells free of exogenous DNA are derived with episomal vectors (fig 1.c); GSE15176: Human induced pluripotent stem cells free of exogenous DNA are derived with episomal vectors (fig 4.a) Experiment Overall Design: Total 21 samples were analyzed to confirm the similarity of human iPS cells derived with episomal vectors with human ES cells, and a dissimilarity with fibroblasts. Experiment Overall Design: Refer to individual Series
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells.
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells.
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells. This SuperSeries is composed of the SubSeries listed below.
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells. Experiment Overall Design: Total of 5 es, 1 fibr, 2 parental, 4 ips sub clones
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells. Experiment Overall Design: Total of 5 es, 1 fibr, 11 parental clones
Project description:In this study, we sought to examine whether an extracellular matrix (ECM)-based xeno-free culture system that we recently established could be used together with a microRNA-enhanced mRNA reprogramming method for the generation of clinically safe iPS cells. The notable features of this method are (1) the use of a xeno-free/feeder-free culture system for the generation and expansion of iPS cells rather than the conventional labor-intensive culture systems using human feeder cells or human feeder-conditioned medium and (2) the enhancement of mRNA-mediated reprogramming via the delivery of microRNAs. Strikingly, we observed the early appearance of iPS cell colonies (~11 days), substantial reprogramming efficiency (~0.2-0.3%), and a high percentage of ESC-like colonies among the total colonies (~87.5%), indicating enhanced kinetics and reprogramming efficiency. Therefore, the combined method established in this study provides a valuable platform for the generation and expansion of clinically safe (i.e., integration- and xeno-free) iPS cells, facilitating immune-matched cell therapy in the near future.
Project description:Previous studies demonstrated that hepatocyte-specific transcription factors could directly convert fibroblasts into functional hepatocytes-like cells, namely induced hepatocytes (iHeps) using viral systems. However, viral integration into host genome causes insertional mutation and risk of tumorigenecity. we showed iHeps could be generated from MEFs using the integration-free system. They were expandable in vitro and showed hepatic features, similar to primary hepatocytes. iHeps_G4H1F3 transfected (Episomal vectors) and iHeps_G4H1F3 transduced (pMXs) were duplicate, respectively. MEFs and primary hepatocytes were used as negative and positive controls, respectively.