Reprogramming is achieved within a single cell cycle after mouse nuclear transfer
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. Overall design: tail tip skin fibroblasts were transferred into mitotic mouse zygotes, blastomeres or oocytes.
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: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: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.
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:Traumatic brain injury (TBI) is a global problem reaching near epidemic numbers that manifests clinically with cognitive problems that decades later may result in dementias like Alzheimer’s disease (AD). Presently, little can be done to prevent ensuing neurological dysfunctions by pharmacological means. Recently, it has become apparent that several CNS diseases share common terminal features of neuronal cell death. The effects of exendin-4 (Ex-4), a neuroprotective agent delivered via a subcutaneous micro-osmotic pump, were examined in the setting of mild TBI (mTBI). Utilizing a model of mTBI, where cognitive disturbances occur over time, animals were subjected to four treatments: sham; Ex-4; mTBI and Ex-4/mTBI. mTBI mice displayed deficits in novel object recognition, while Ex-4/mTBI mice performed similar to sham. Hippocampal gene expression, assessed by gene array methods, showed significant differences with little overlap in co-regulated genes between groups. Importantly, changes in gene expression induced by mTBI, including genes associated with AD were largely prevented by Ex-4. These data suggest a strong beneficial action of Ex-4 in managing secondary events induced by a traumatic brain injury. Male ICR mice weighing 30–40 g were kept five per cage under a constant 12-h light/dark cycle, at room temperature (23°C). Food (Purina rodent chow) and water were available ad libitum. Each mouse was used for one experiment and for one time point only. The Ethics Committee of the Sackler Faculty of Medicine approved the experimental protocol (M-09-055), in compliance with the guidelines for animal experimentation of the National Institutes of Health (DHEW publication 85–23, revised, 1995). A minimal number of mice were used for the study and all efforts were made to minimize suffering. All experimental manipulations were conducted during the light phase of the cycle. Experimental mTBI was induced using the 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 consists 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 temporal right side 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. Immediately after the injury, mice were placed back in their cages for recovery. The effect of the injury upon behavior and cognition was studied from 7 days following the trauma. Sham treated mouse groups were treated identically only the weight was not dropped. The peptide Ex-4 was obtained from Bachem (Torrance, CA). In order to obtain a constant steady-state concentration of Ex-4 in mice prior to injury; Ex-4 was delivered by use of micro-osmotic pumps (7 day infusion duration), 2 days prior to the induction of mTBI. For the Ex-4 treated animals the peptide was dissolved in an equal volume of saline and dimethyl sulfoxide (DMSO) mixture and delivered from a subcutaneously implanted ALZET Micro-osmotic pump (Model 1007D, Alzet, Cupertino, CA) at a rate of 3.5 pM/kg/min. In drug treatment control groups, saline and DMSO pumps were implanted in each animal following the same surgical procedure as used for the Ex-4 treatment animals. In all animals, pumps were placed, posterior to the scapulae. Pump implantation was performed under anesthesia (ketamine/xylazine) utilizing sterile procedures. Mini pumps were implanted 48 hours prior to the weight drop injury. The number of animals from each treatment group that went on to microarray analysis were as follows, Sham, n = 5; mTBI, n = 4; Ex-4, n = 5; Ex-4/ mTBI, n = 4. Mouse cognition was assessed using the novel object recognition paradigm. After the completion of the novel object behavioral assessment, animals were euthanized and the hippocampus dissected for total RNA isolation. Total RNA was prepared using the Qiagen RNeasy Mini Kit (Qiagen, Inc. Valencia CA) following the manufacturer's specifications. Quantity and quality of the RNA was assessed using the Agilent 2100 Bioanalyzer with RNA 6000 Nano Chips. The total RNA (500 ng) was used to generate biotin-labeled cRNA using the Illumina TotalPrep RNA Amplification Kit (Ambion; Austin, TX, cat # IL1791). In short, 500 ng of total RNA was first converted into single-stranded cDNA with reverse transcriptase using an oligo-dT primer containing the T7 RNA polymerase promoter site and then copied to produce double-stranded cDNA molecules. The double stranded cDNA was cleaned and concentrated with the supplied columns and used in an overnight in vitro transcription reaction where single-stranded RNA (cRNA) was generated and labeled by incorporation of biotin-16-UTP. This cRNA was used in the hybridization reaction. Briefly, a total of 750 ng of biotin-labeled cRNA was hybridized at 58oC for 16 hours to Illumina's SentrixMouse Ref-8, v2 Expression BeadChips (Illumina, San Diego, CA). Each BeadChip has ~24,000 well-annotated RefSeq transcripts with an approximately 30-fold redundancy. The arrays were washed, blocked and the biotin labeled cRNA was detected by staining with streptavidin-Cy3. Arrays were scanned at a resolution of 0.8 m using the Beadstation 500 X from Illumina, data was extracted from the image using Illumina BeadStudio software, v3.4.0.
Project description:Induced pluripotent stem cells (iPSCs) offer opportunity for insight into the genetic requirements of the X chromosome for somatic and germline development. Turner syndrome is caused by complete or partial loss of the second sex chromosome; while more than 90% of Turner cases result in spontaneous fetal loss, survivors display an array of somatic and germline clinical characteristics. Here, we derived iPSCs from Turner syndrome and control individuals and examined germ cell development as a function of X chromosome composition. We analyzed gene expression profiles of derived iPSCs and in vitro differentiated cells by single cell qRT-PCR and RNA-seq. We whoed that two X chromosomes are not necessary for reprogramming or pluripotency maintenance. Genes that escape X chromosome inactivation (XCI) between control iPSCs and those with X chromosome aneuploidies revealed minimal expression differences relative to a female hESC line. Moreover, when we induced germ cell differentiation via murine xenotransplantation of iPSC lines into the seminiferous tubules of busulfan-treated mice, we observed that undifferentiated iPSCs, independent of X chromosome composition, when placed within the correct somatic environment, are capable of forming early germ cells in vivo. Results indicate that two intact X chromosomes are not required for germ cell formation; however, clinical data suggest that two sex chromosomes are required for maintenance of human germ cells. RNA-seq of H9 cells, iPSCs from Turner syndrome and control individuals and in vitro differentiated cells
Project description:To simulate transient B cell activation that is the likely initiator of T-dependent responses, we examined the molecular and functional consequences of a single-round of immunoglobulin M (IgM) signaling. This form of activation triggered early cytosolic signaling and transcription factor NF-kB activation indistinguishably from conventional continuous IgM cross-linking, but did not induce G1 progression. However, single-round IgM signaling changed the expression of chemokine and chemokine receptor genes implicated in initiating T-dependent responses, as well as accentuated responsiveness to CD40 signaling. Several features of single-round IgM signaling in vitro were recapitulated in B cells after short-term exposure to antigen in vivo. We propose that transient BCR signals prime B cells to receive T cell help by increasing the probability of B-T encounter and creating a cellular environment that is hyper-responsive to CD40 signaling. Primary B lymphocytes were isolated using Auto-MACS (Miltenyi Biotec) by negative selection. B cell purity was 90-95% based on flow cytometric analysis with CD19 staining. Purified B cells (2x10^6/ml) were cultured in RPMI 1640 supplemented with 10% heat-inactivated FBS, 55nM beta-mercaptoethanol, 2mM L-glutamine and 100IU penicillin and 100ug/ml streptomycin at 37degrees C. For pulsed anti-IgM treatment experiments, B cells were incubated with 10ug/ml goat anti-mouse IgM F(ab’)2 (Jackson ImmunoResearch Laboratories) at 4 degrees C for 30 min. Unbound anti-IgM was removed from the medium by washing and centrifuging the cells at 4 degrees C. The cells were resuspended in chilled complete medium and shifted to 37 degrees C by placing in an incubator or in water-bath. For continuous anti-IgM treatment experiments, B cells were stimulated with 10ug/ml anti-IgM at 4 degrees C for 30 min, then incubated at 37 degrees C.