Reprogramming is achieved within a single cell cycle after mouse nuclear transfer
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ABSTRACT: Although nuclear transfer allows the reprogramming of somatic cells to totipotency, little is known concerning the kinetics by which it takes place or the minimum requirements for its success. Here, we demonstrate that reprogramming can be achieved within a few hours and a single cell-cycle as long as two key constraints on reprogramming are satisfied. First, the recipient cell chromosomes must be removed during mitosis. Second, the nuclear envelope of the donor cell must be broken down and its chromosomes condensed, allowing an embryonic nucleus to be constructed around the incoming chromosomes. If these requirements are not met, then reprogramming fails and embryonic development arrests. These results point to a central role for processes intimately linked to cell division in mediating efficient transitions between transcriptional programs. tail tip skin fibroblasts were transferred into mitotic mouse zygotes, blastomeres or oocytes.
Project description:Although nuclear transfer allows the reprogramming of somatic cells to totipotency, little is known concerning the kinetics by which it takes place or the minimum requirements for its success. Here, we demonstrate that reprogramming can be achieved within a few hours and a single cell-cycle as long as two key constraints on reprogramming are satisfied. First, the recipient cell chromosomes must be removed during mitosis. Second, the nuclear envelope of the donor cell must be broken down and its chromosomes condensed, allowing an embryonic nucleus to be constructed around the incoming chromosomes. If these requirements are not met, then reprogramming fails and embryonic development arrests. These results point to a central role for processes intimately linked to cell division in mediating efficient transitions between transcriptional programs.
Project description:Reprogramming occurs after nuclear transfer into zygotes whose genome was removed in mitosis, but not after nuclear transfer into zygotes enucleated in interphase Egli et al. Development 2010 doi:10.1242/dev.046151 Groups of 20 mouse embryos were used for the analysis. RNA amplification was done using Illumina total prep RNA amplification kit. Total of 21 arrays.
Project description: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 cell types 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 activated after genome exchange invariably arrests at the 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, they efficiently develop to the blastocyst stage. Human 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 the removal of the oocyte genome as the primary cause of developmental failure after genome exchange. Future work should focus on the critical elements that are associated with the human oocyte genome. Stem cells were derived by reprogramming of skin cells using oocytes ('nuclear transfer') or defined factors (iPS cells), or from IVF blastocysts
Project description:Reprogramming occurs after nuclear transfer into zygotes whose genomes have been removed in mitosis, but not after nuclear transfer into zygotes enucleated in interphase. Our results suggest that there is a previously unappreciated barrier to successful human nuclear transfer, and that future studies should focus on the requirements for somatic genome activation. 1-3 embryos were used for analysis. RNA amplification was done using two or three rounds of T7-mediated RNA amplification using the Illumina Total Prep RNA Amplification kit. Somatic cells 1-000 and 1-011 required only one round of RNA amplification because starting amounts of RNA were 100-500ng, while embryonic samples were amplified from single cells or embryos.
Project description:This SuperSeries is composed of the following subset Series: GSE27507: Gene expression in pluripotent stem cells derived after somatic cell genome transfer into human oocytes GSE28022: Gene expression in blastomeres after transfer of somatic cells into human oocytes Refer to individual Series
Project description: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 cell types 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 activated after genome exchange invariably arrests at the 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, they efficiently develop to the blastocyst stage. Human 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 the removal of the oocyte genome as the primary cause of developmental failure after genome exchange. Future work should focus on the critical elements that are associated with the human oocyte genome. Somatic cells were transferred into human unfertilized oocytes to determine if human oocytes can reprogram a somatic cell.
Project description:Platelet-derived growth factor-CC (PDGF-CC) is the third member of the PDGF family discovered after more than two decades of studies on the original members of the family, PDGF-AA and PDGF-BB. The biological function of PDGF-CC remains largely to be explored. We report here a novel finding that PDGF-CC is a potent neuroprotective factor that acts by modulating glycogen synthase kinase (GSK)3beta activity. In several different animal models of neuronal injury, such as axotomy-induced neuronal death, neurotoxin-induced neuronal injury, 6-OHDA-induced Parkinson's dopaminergic neuronal death and ischemia-induced stroke, PDGF-CC protein or gene delivery protected different types of neurons from apoptosis in both the retina and brain. On the other hand, loss-of-function assays using PDGF-C null mice, neutralizing antibody or shRNA showed that PDGF-CC deficiency/inhibition exacerbated neuronal death in different neuronal tissues in vivo. Mechanistically, we revealed that the neuroprotective effect of PDGF-CC was achieved by regulating GSK3beta phosphorylation and expression. Our data demonstrate that PDGF-CC is critically required for neuronal survival, and may potentially be used to treat neurodegenerative diseases. Inhibition of the PDGF-CC/receptor pathway for different clinical purposes should be conducted with caution to preserve normal neuronal functions. PDGF-C deficient mice were bred onto C57BL/6 background for more than six generations and littermates were used. After optic nerve crush (ONC), PDGF-CC protein à 1 µl of active recombinant human PDGF-CC protein 0.5 µg/µl (rhPDGF-CC) was injected into mouse vitreous once a week for two weeks. Seven days after the ONC injury and PDGF-CC protein treatment, retinae were harvested and total RNA isolated using the TRIzol reagent (Invitrogen) followed by the RNeasy Mini kit (Qiagen) purification according to the manufacturer's instructions. Microarray assay was performed using the Mouse-6 Expression BeadChips containing approximately 24,000 annotated mouse transcripts (Illumina Inc). Three biological repeats were included in the microarray assay. Two tailed Student's t-test was used for statistical analysis of gene expression data. Functional grouping of the differentially expressed genes was performed using several different tools including the WebGestalt (http://bioinfo.vanderbilt.edu/webgestalt) and the Ingenuity Pathways Analysis (https://analysis.ingenuity.com/pa/login/login.jsp). The supplementary file 'GSE19207_non-normalized.txt' contains raw data for Samples GSM476021-GSM476026.
Project description:Warfare has long been associated with traumatic brain injury (TBI) in militarized zones. Common forms of TBI can be caused by a physical insult to the head-brain or by the effects of a high velocity blast shock wave generated by the detonation of an explosive device. While both forms of trauma are distinctly different regarding the mechanism of trauma induction, there are striking similarities in the cognitive and emotional status of survivors. Presently, proven effective therapeutics for the treatment of either form of TBI are unavailable. To be able to develop efficacious therapies, studies involving animal models of physical- and blast-TBI are required to identify possible novel or existing medicines that may be of value in the management of clinical events. We examined indices of cognition and anxiety-like behavior and the hippocampal gene transcriptome of mice subjected to both forms of TBI. We identified common behavioral deficits and gene expression regulations, in addition to unique injury-specific forms of gene regulation. Molecular pathways presented a pattern similar to that seen in gene expression. Interestingly, pathways connected to AlzheimerM-bM-^@M-^Ys disease displayed a markedly different form of regulation depending on the type of TBI. While these data highlight similarities in behavioral outcomes after trauma, the divergence in hippocampal transcriptome observed between models suggests that, at the molecular level, the TBIs are quite different. These models may provide tools to help define therapeutic approaches for the treatment of physical- and blast-TBIs. Based upon observations of increasing numbers of personnel displaying TBI related emotional and behavioral changes in militarized zones, the development of efficacious therapies will become a national if not a global priority. Keywords: Physical-traumatic brain injury; Blast-traumatic brain injury; Cognitive dysfunction; Gene expression; Molecular pathway(s); Neurodegeneration; Stem cells; AlzheimerM-bM-^@M-^Ys disease A mild physical-TBI was induced using a concussive head trauma device described previously (Milman et al., 2005; Zohar et al., 2003). Briefly, mice were lightly anesthetized (Isoflurane) and placed under the weight-drop concussive head trauma instrument. The device consisted of a metal tube (inner diameter 13 mm), placed vertically over the mouse head. A metal weight (30 g) was dropped from the top of the tube (80 cm) and struck the skull at the right side temporal area between the corner of the eye and the ear. A sponge supported the head, allowing some antero-posterior motion without any rotational head movement at the moment of the impact. Experimental conditions used to create a mild low-level blast-TBI and the subsequent model characterization, have been described in detail elsewhere (Rubovitch et al., 2011). In brief, mice were anaesthetized with a combination of ketamine (100 mg/kg) and xylazine (10 mg/kg). Once the animals were fully anaesthetized they were placed at a defined distance from a detonation source, in this case 7 meters. Pressure sensors were used to measure the explosion shock wave pressure (PSI) generated by the detonation (Free-Field ICPM-BM-. Blast Pressure Sensor; PCB Piezoelectronics, Depew, NY, USA, Model 137). At 7 meters from the source of the detonation, the animals were exposed to a maximum of a 2.5 PSI (17.2 kPa) pressure shock wave. Immediately after the induction of the injury, mice were placed back in their cages. Once the animals had recovered from the anesthesia, basic neurological assessments were undertaken to identify any acute neurological dysfunction. Only animals exhibiting no evidence of acute neurological damage post injury were subsequently used in further experiments. Sham treated mouse groups were treated identically; however, they were not exposed to physical- or blast-TBI. Mouse hippocampus tissues were randomly selected from the larger library of samples generated from the behavioral experiments and the numbers utilized in the gene expression study were as follows: sham, n = 5: physical-TBI, n = 4; blast-TBI, n = 7.
Project description:The identified stromal factors SDF1alpha, sFRP1 and VEGFD induce dopaminergic neuron differentiation of human pluripotent stem cells. Human embryonic stem cell (hESC)-derived dopaminergic (DA) neurons are potentially useful for treating Parkinson’s disease (PD) through cell replacement therapy. Generation of DA neurons from hESCs has been achieved by co-culture with the stromal cell line PA6, a source of stromal cell-derived inducing activity (SDIA). However, the factor(s) produced by stromal cells that constitute SDIA is unknown. We previously reported that medium conditioned by PA6 cells can generate functional DA neurons in the human embryonal carcinoma stem cell line, NTera2. Here we further examined the effects of PA6-conditioned medium and found that it can induce DA neuronal differentiation in both the NTera2 cell line and the hESC line, I6. To identify the factor(s) responsible for SDIA, we used large-scale microarray analysis of gene expression combined with proteomic analysis of PA6-conditioned medium. Four candidate factors (hepatocyte growth factor (HGF), stromal cell-derived factor-1 alpha (SDF1alpha), secreted frizzled-related protein 1 (sFRP1) and vascular endothelial growth factor D (VEGFD)) were identified and immunoaffinity capillary electrophoresis (ICE) was used to establish the protein concentration of these factors in conditioned medium. Upon addition of SDF1alpha, sFRP1, and VEGFD, we observed an increase in the number of tyrosine hydroxylase- and TuJ1- positive cells in both the NTera2 and I6 cell lines. These results indicate that SDF1alpha, sFRP1 and VEGF-D are major components of SDIA, and suggest the potential use of these defined factors to elicit dopaminergic differentiation of pluripotent stem cells as a therapeutic intervention in PD. Mouse embryonic fibroblasts were grown in DMEM medium supplemented with 10% FBS; this conditioned media was used as the control. PA6, mouse stromal cells, were grown in MEM-alpha supplemented with 10% FBS; this conditioned media is known to induce differentiation in hES cells.