The Experts below are selected from a list of 11787 Experts worldwide ranked by ideXlab platform

Matthew Freeby - One of the best experts on this subject based on the ideXlab platform.

  • human oocytes reprogram somatic cells to a Pluripotent State
    Nature, 2011
    Co-Authors: Scott Noggle, Holim Fung, Athurva Gore, Hector Martinez, Kathleen Crumm Satriani, Robert W Prosser, Kiboong Oum, Daniel Paull, Sarah Druckenmiller, Matthew Freeby
    Abstract:

    The exchange of the oocyte's genome with the genome of a somatic cell, followed by the derivation of Pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient's genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a Pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange.

  • human oocytes reprogram somatic cells to a Pluripotent State
    Nature, 2011
    Co-Authors: Scott Noggle, Holim Fung, Athurva Gore, Hector Martinez, Kathleen Crumm Satriani, Robert W Prosser, Kiboong Oum, Daniel Paull, Sarah Druckenmiller, Matthew Freeby
    Abstract:

    The exchange of the oocyte’s genome with the genome of a somatic cell, followed by the derivation of Pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient’s genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a Pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange. The generation of animals by transfer of the genome from an adult cell into an unfertilized oocyte 1 , and the isolation of Pluripotent stem cells from human blastocysts 2 , raised the prospect of generating stem cells with a patient’s genome. This prospect holds much medical promise as these patient-specific stem cells could be used to generate differentiated cells for cell replacement. Unfortunately, progress towards this goal has been slowed by legal and social considerations limiting the availability of human oocytes for research. Despite these limitations, several studies were conducted 3–11 , but none have achieved the

Shinya Yamanaka - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear reprogramming to a Pluripotent State by three approaches
    Nature, 2010
    Co-Authors: Shinya Yamanaka, Helen M. Blau
    Abstract:

    The stable States of differentiated cells are now known to be controlled by dynamic mechanisms that can easily be perturbed. An adult cell can therefore be reprogrammed, altering its pattern of gene expression, and hence its fate, to that typical of another cell type. This has been shown by three distinct experimental approaches to nuclear reprogramming: nuclear transfer, cell fusion and transcription-factor transduction. Using these approaches, nuclei from 'terminally differentiated' somatic cells can be induced to express genes that are typical of embryonic stem cells, which can differentiate to form all of the cell types in the body. This remarkable discovery of cellular plasticity has important medical applications.

  • induction of Pluripotent stem cells from adult human fibroblasts by defined factors
    Obstetrical & Gynecological Survey, 2008
    Co-Authors: Kazutoshi Takahashi, Koji Tanabe, Mari Ohnuki, Megumi Narita, Tomoko Ichisaka, Kiichiro Tomoda, Shinya Yamanaka
    Abstract:

    ABSTRACTIf it were possible to reprogram differentiated human somatic cells into a Pluripotent State, patient-specific and disease-specific stem cells could be developed. Previous work generated induced Pluripotent stem (iPS) cells capable of germline transmission from murine somatic cells by transd

  • induction of Pluripotent stem cells from adult human fibroblasts by defined factors
    Cell, 2007
    Co-Authors: Kazutoshi Takahashi, Koji Tanabe, Mari Ohnuki, Megumi Narita, Tomoko Ichisaka, Kiichiro Tomoda, Shinya Yamanaka
    Abstract:

    SUMMARY Successful reprogramming of differentiated human somatic cells into a Pluripotent State would allow creation of patient- and disease-specific stem cells. We previously reported generation of induced Pluripotent stem (iPS) cells, capable of germline transmission, from mouse somatic cells by transduction of four defined transcription factors. Here, we demonstrate the generationofiPS cells from adult human dermal fibroblasts with the same four factors: Oct3/4, Sox2, Klf4, and c-Myc. Human iPS cells were similar to human embryonic stem (ES) cells in morphology, proliferation, surface antigens, gene expression, epigenetic status of Pluripotent cell-specific genes, and telomerase activity. Furthermore, these cells could differentiate into cell types of the three germ layers in vitro and in teratomas. These findings demonstrate that iPS cells can be generated from adult human fibroblasts.

Scott Noggle - One of the best experts on this subject based on the ideXlab platform.

  • human oocytes reprogram somatic cells to a Pluripotent State
    Nature, 2011
    Co-Authors: Scott Noggle, Holim Fung, Athurva Gore, Hector Martinez, Kathleen Crumm Satriani, Robert W Prosser, Kiboong Oum, Daniel Paull, Sarah Druckenmiller, Matthew Freeby
    Abstract:

    The exchange of the oocyte's genome with the genome of a somatic cell, followed by the derivation of Pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient's genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a Pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange.

  • human oocytes reprogram somatic cells to a Pluripotent State
    Nature, 2011
    Co-Authors: Scott Noggle, Holim Fung, Athurva Gore, Hector Martinez, Kathleen Crumm Satriani, Robert W Prosser, Kiboong Oum, Daniel Paull, Sarah Druckenmiller, Matthew Freeby
    Abstract:

    The exchange of the oocyte’s genome with the genome of a somatic cell, followed by the derivation of Pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient’s genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a Pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange. The generation of animals by transfer of the genome from an adult cell into an unfertilized oocyte 1 , and the isolation of Pluripotent stem cells from human blastocysts 2 , raised the prospect of generating stem cells with a patient’s genome. This prospect holds much medical promise as these patient-specific stem cells could be used to generate differentiated cells for cell replacement. Unfortunately, progress towards this goal has been slowed by legal and social considerations limiting the availability of human oocytes for research. Despite these limitations, several studies were conducted 3–11 , but none have achieved the

Kazutoshi Takahashi - One of the best experts on this subject based on the ideXlab platform.

  • cellular reprogramming lowering gravity on waddington s epigenetic landscape
    Journal of Cell Science, 2012
    Co-Authors: Kazutoshi Takahashi
    Abstract:

    During development, cell fate is specified precisely through programming by multiple complex elements and processes, including chromatin modifications that result in epigenetic marks. Once determined, cell fate is specified further only through maturation processes, which include differentiation and senescence. However, recent studies have shown that it is possible to influence cell fate through artificial manipulation. For example, the exogenous expression of a set of transcription factors can result in the reprogramming of differentiated skin fibroblasts to a Pluripotent State. In addition, recent reports have demonstrated the directed reprogramming of one type of differentiated somatic cell to another type of differentiated somatic cell, without rejuvenation to a Pluripotent State. Reprogramming factors blur the boundaries between different cell fates, which can never meet, as if the hierarchy were flattened by 'lowering gravity'. Although attempts to use direct reprogramming to generate certain cell types, such as those found in the kidneys and the lungs, have remained unsuccessful, recent advances suggest that we are nearing the identification of determinants that allow cells to be directly reprogrammed into cell types from all organs in the not too distant future. This Commentary summarises our current knowledge on cellular reprogramming, and more specifically, recent advances in direct reprogramming to generate a variety of cell types.

  • induction of Pluripotent stem cells from adult human fibroblasts by defined factors
    Obstetrical & Gynecological Survey, 2008
    Co-Authors: Kazutoshi Takahashi, Koji Tanabe, Mari Ohnuki, Megumi Narita, Tomoko Ichisaka, Kiichiro Tomoda, Shinya Yamanaka
    Abstract:

    ABSTRACTIf it were possible to reprogram differentiated human somatic cells into a Pluripotent State, patient-specific and disease-specific stem cells could be developed. Previous work generated induced Pluripotent stem (iPS) cells capable of germline transmission from murine somatic cells by transd

  • induction of Pluripotent stem cells from adult human fibroblasts by defined factors
    Cell, 2007
    Co-Authors: Kazutoshi Takahashi, Koji Tanabe, Mari Ohnuki, Megumi Narita, Tomoko Ichisaka, Kiichiro Tomoda, Shinya Yamanaka
    Abstract:

    SUMMARY Successful reprogramming of differentiated human somatic cells into a Pluripotent State would allow creation of patient- and disease-specific stem cells. We previously reported generation of induced Pluripotent stem (iPS) cells, capable of germline transmission, from mouse somatic cells by transduction of four defined transcription factors. Here, we demonstrate the generationofiPS cells from adult human dermal fibroblasts with the same four factors: Oct3/4, Sox2, Klf4, and c-Myc. Human iPS cells were similar to human embryonic stem (ES) cells in morphology, proliferation, surface antigens, gene expression, epigenetic status of Pluripotent cell-specific genes, and telomerase activity. Furthermore, these cells could differentiate into cell types of the three germ layers in vitro and in teratomas. These findings demonstrate that iPS cells can be generated from adult human fibroblasts.

Stuart H. Orkin - One of the best experts on this subject based on the ideXlab platform.

  • Chromatin Connections to Pluripotency and Cellular Reprogramming
    Cell, 2011
    Co-Authors: Stuart H. Orkin, Konrad Hochedlinger
    Abstract:

    The Pluripotent State of embryonic stem cells (ESCs) provides a unique perspective on regulatory programs that govern self-renewal and differentiation and somatic cell reprogramming. Here, we review the highly connected protein and transcriptional networks that maintain pluripotency and how they are intertwined with factors that affect chromatin structure and function. The complex interrelationships between pluripotency and chromatin factors are illustrated by X chromosome inactivation, regulatory control by noncoding RNAs, and environmental influences on cell States. Manipulation of cell State through the process of transdifferentiation suggests that environmental cues may direct transcriptional programs as cells enter a transiently "plastic" State during reprogramming.

  • use of in vivo biotinylation to study protein protein and protein dna interactions in mouse embryonic stem cells
    Nature Protocols, 2009
    Co-Authors: Stuart H. Orkin, Alan B Cantor, Jonghwan Kim, Jianlong Wang
    Abstract:

    In gene regulation, proteins function as members of protein complexes to recognize chromosomal target DNA loci. In dissecting the Pluripotent State in mouse embryonic stem (mES) cells, we have used in vivo biotinylation of critical transcription factors for affinity purification of protein complexes and chromatin immunoprecipitation (ChIP)-on-chip for target identification, respectively. Here, we describe detailed procedures for such studies to dissect protein-protein and protein-DNA interactions in mES cells. Specifically, the following three procedures will be described: (i) in vivo biotinylation system setup in mES cells; (ii) affinity purification of multiprotein complexes by one-step streptavidin capture and tandem anti-FLAG/streptavidin affinity purification; (iii) biotin-mediated ChIP (bioChIP). The system setup takes approximately 50 d to complete, and it takes another approximately 15 d and approximately 3 d to perform affinity purification of protein complexes and bioChIP, respectively.

  • Tandem affinity purification of protein complexes in mouse embryonic stem cells using in vivo biotinylation.
    Current protocols in stem cell biology, 2009
    Co-Authors: Jianlong Wang, Alan B Cantor, Stuart H. Orkin
    Abstract:

    In dissecting the Pluripotent State in mouse embryonic stem (ES) cells, we have employed in vivo biotinylation of critical transcription factors for streptavidin affinity purification of protein complexes and constructed a protein-protein interaction network. This has facilitated discovery of novel pluripotency factors and a better understanding of stem cell pluripotency. Here we describe detailed procedures for in vivo biotinylation system setup in mouse ES cells, and affinity purification of multi-protein complexes using in vivo biotinylation. In addition, we present a protocol employing SDS-PAGE fractionation to reduce sample complexity prior to submission for mass spectrometry (MS) protein identification.

  • an extended transcriptional network for pluripotency of embryonic stem cells
    Cell, 2008
    Co-Authors: Jonghwan Kim, Jianlong Wang, Jianlin Chu, Xiaohua Shen, Stuart H. Orkin
    Abstract:

    Much attention has focused on a small set of transcription factors that maintain human or mouse embryonic stem (ES) cells in a Pluripotent State. To gain a more complete understanding of the regulatory network that maintains this State, we identified target promoters of nine transcription factors, including somatic cell reprogramming factors (Oct4, Sox2, Klf4, and c-Myc) and others (Nanog, Dax1, Rex1, Zpf281, and Nac1), on a global scale in mouse ES cells. We found that target genes fall into two classes: promoters bound by few factors tend to be inactive or repressed, whereas promoters bound by more than four factors are largely active in the Pluripotent State and become repressed upon differentiation. Furthermore, we propose a transcriptional hierarchy for reprogramming factors and broadly distinguish targets of c-Myc versus other factors. Our data provide a resource for exploration of the complex network maintaining pluripotency.