Genome-wide analysis reveals conserved transcriptional responses downstream of resting potential change in Xenopus embryos, axolotl regeneration, and human mesenchymal cell differentiation
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ABSTRACT:
ORGANISM(S): Ambystoma mexicanum
SUBMITTER: Christopher Martyniuk
PROVIDER: E-GEOD-72099 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Endogenous bioelectric signaling via changes in cellular resting potential (Vmem) is a key regulator of patterning during regeneration and embryogenesis in numerous model systems. Depolarization of Vmem has been functionally implicated in de-differentiation, tumorigenesis, anatomical re-specification, and appendage regeneration. However, no unbiased analyses have been performed to understand genome-wide transcriptional responses to Vmem change in vivo. Moreover, it is unknown which genes or gene networks represent conserved targets of bioelectrical signaling across different patterning contexts and species. Here, we use microarray analysis to comparatively analyze transcriptional responses to specific Vmem depolarization. We compare the response of the transcriptome during embryogenesis (Xenopus development), regeneration (Axolotl regeneration), and stem cell differentiation (human mesenchymal stem cells in culture) to identify common networks across model species that are associated with depolarization. Both sub-network enrichment and PANTHER analyses identified a number of key genetic modules as targets of Vmem change, and also revealed important (well-conserved) commonalities in bioelectric signal transduction, despite highly diverse experimental contexts and species. Depolarization regulates specific transcriptional networks across all three germ layers (ectoderm, mesoderm and endoderm) such as cell differentiation and apoptosis, and this information will be used for developing mechanistic models of bioelectric regulation of patterning. Moreover, our analysis reveals that Vmem change regulates transcripts related to important disease pathways such as cancer and neurodegeneration, which may represent novel targets for emerging electroceutical therapies. Xenopus laevis embryos were fertilized in vitro according to standard protocols (Sive 2000) in 0.1X Marcâs Modified Ringerâs (MMR; 10mM Na+, 0.2mM K+,10.5mM Cl, 0.2 mM Ca2+, pH 7.8). Intracellular ion concentrations in Xenopus embryo are: 21mM Na+, 90mM K+, 60mM Cl-, 0.5mM Ca2+ (Gillespie 1983). Xenopus embryos were housed at 14-18oC and staged according to Nieuwkoop and Faber (Nieuwkoop 1967). All experiments were approved by the Tufts University Animal Research Committee (M2014-79) in accordance with the guide for care and use of laboratory animals. Capped synthetic mRNAs generated using mMessage mMachine kit (Ambion) were dissolved in nuclease free water and injected into the embryos in 3% Ficoll using standard methods (Sive 2000). Each injection delivered between 1-2 nL or 1â 2 ng of mRNA (per blastomere) into the embryos, usually at 4-cell stage into the middle of the cell in the animal pole. Constructs used were: GlyR (Davies et al. 2003) and 666 chimera (Hough et al. 2000).
2016-07-03 | E-GEOD-72097 | biostudies-arrayexpress
Project description:Depolarization of resting membrane potential in select cells in Xenopus larvae induces striking hyperpigmentation due to dysregulation of melanocytes. Here, we show that this non-cell-autonomous process is mediated by cAMP, CREB, and the transcription factors Sox10 and Slug. Our microarray analysis reveals specific transcripts responsive to Vmem levels within a few hours of depolarization, and a set of 517 transcripts whose expression remains altered during the full hyperpigmented phenotype over a week later, linking instructor cell-depolarization to a range of developmental processes and disease states. We also show that voltage-dependent conversion of melanocytes involves the MSH-secreting melanotrope cells of the pituitary, and formulate a model for the molecular pathway linking the bioelectric properties of melanocyte cellsâ microenvironment in vivo to the genetic and cellular changes induced in this melanoma-like phenotype. Remarkably, the phenotype is all-or-none: each individual animal either undergoes melanocyte conversion or not, as a whole. This group decision is stochastic, resulting in varying percentages of hyperpigmented individuals for a given experimental treatment. To understand the stochasticity and dynamic properties of this complex signaling system, we developed a novel computational method that automates the reverse-engineering of stochastic dynamic signaling models. We used this method to discover a network model that quantitatively explained our complex dataset, and even made correct predictions for new experiments that we validated in vivo. Taken together, these data (1) reveal new molecular details about a novel trigger of metastatic-like developmental cell behavior in vivo, (2) suggest new targets for biomedical intervention, and (3) demonstrate proof-of-principle of a computational method for understanding stochastic decision-making by cells during embryonic development and metastasis. Gene expression analysis was performed using samples treated with ivermectin from NF stage 10 onwards, collected at two developmental stages; stage 15 (early neurula) and stage 45 (free-swimming tadpole). Embryos were collected in eppendorf tubes (N=50 for stage 15, N=5 for stage 45) and frozen at -80°C. RNA extraction and microarray analysis were performed by the Beth Israel Deaconess Medical Center Genomics and Proteomics Center (Harvard) according to standard Affymetrix protocol, using a high throughput hybridization and scanning system. Microarray hybridization was performed using the Affy 3â IVT Express Kit. Fragmented and biotin labeled and amplified RNA was hybridized to the GeneChip® Xenopus laevis Genome 2.0 array as per manufacturerâs protocol. The Affymetrix GeneChip® X. laevis Genome 2.0 Array, has 32,400 probe sets representing more than 29,900 X. laevis transcripts.
2015-11-03 | E-GEOD-70834 | biostudies-arrayexpress
Project description:Endogenous bioelectric signaling via changes in cellular resting potential (Vmem) is a key regulator of patterning during regeneration and embryogenesis in numerous model systems. Depolarization of Vmem has been functionally implicated in de-differentiation, tumorigenesis, anatomical re-specification, and appendage regeneration. However, no unbiased analyses have been performed to understand genome-wide transcriptional responses to Vmem change in vivo. Moreover, it is unknown which genes or gene networks represent conserved targets of bioelectrical signaling across different patterning contexts and species. Here, we use microarray analysis to comparatively analyze transcriptional responses to specific Vmem depolarization. We compare the response of the transcriptome during embryogenesis (Xenopus development), regeneration (Axolotl regeneration), and stem cell differentiation (human mesenchymal stem cells in culture) to identify common networks across model species that are associated with depolarization. Both sub-network enrichment and PANTHER analyses identified a number of key genetic modules as targets of Vmem change, and also revealed important (well-conserved) commonalities in bioelectric signal transduction, despite highly diverse experimental contexts and species. Depolarization regulates specific transcriptional networks across all three germ layers (ectoderm, mesoderm and endoderm) such as cell differentiation and apoptosis, and this information will be used for developing mechanistic models of bioelectric regulation of patterning. Moreover, our analysis reveals that Vmem change regulates transcripts related to important disease pathways such as cancer and neurodegeneration, which may represent novel targets for emerging electroceutical therapies. All axolotls used in these experiments were bred in the axolotl facility at the University of Minnesota under the IACUC protocol #1201A08381. Axolotls of 2â3 cm were used for all in vivo experiments, and animals were kept in separate containers and fed daily with artemia; water was changed daily. Animals were anesthetized in 0.01% p-amino benzocaine (Sigma) before microinjection was performed. There were 9 microarrays conducted, and these were ivermectin-treated (n=3). Experimental Design: Ivermectin injection Ivermectin or vehicle only (water) was pressure injected into the central canal of the spinal cord, and this was visualized by the addition of Fast Green into the solution. Directly after injection, a portion of the spinal cord was surgically removed and the animals were placed back into water in individual containers. One day post injury (1dpi) animals were anesthetized again and the area of the injury was removed. Tissue from 10 animals were pooled for each microarray replicate. Mature - Uninjured spinal cord tissue Sc Crush- spinal cord tissue 1 day after injury Ivermectin - Ivermectin injected spinal cord tissue 1 day after injury.
2016-07-03 | E-GEOD-72096 | biostudies-arrayexpress
Project description:Human Natural Killer (NK) cells comprise two main subsets, CD56bright and CD56dim cells, that differ in function, phenotype and tissue localization. To further dissect the heterogeneity of CD56dim cells, we have performed transcriptome analysis and functional ex vivo characterization of human NK cell subsets according to the expression of markers related to differentiation, migration or competence. Here, we show for the first time that the ability to respond to cytokines or to activating receptors is mutually exclusive in almost all NK cells with the exception of CD56dim CD62L+ cells. Indeed, only these cells combine the ability to produce interferon (IFN)-gamma after cytokines and proliferate in vivo during viral infection with the capacity to kill and produce cytokines upon engagement of activating receptors. Therefore, CD56dim CD62L+ cells represent a unique subset of polyfunctional NK cells. Ex vivo analysis of their function, phenotype, telomere length, frequencies during ageing as well as transfer experiments of NK cell subsets into immunodeficient mice suggest that CD56dim CD62L+ cells represent an intermediate stage of NK cell maturation, which after restimulation can accomplish multiple tasks and further develop into terminally differentiated effectors. Gene expression profiles of FACSAria sorted CD3- CD56bright CD62L+, CD3- CD56dim CD62L+ and CD3- CD56dim CD62L- NK cells from human peripheral blood of three donors were compared using Affymetrix GeneChip Human Genome HG-U133_Plus_2. After total RNA extraction, reverse transcription, cDNA extraction, the biotinylated cRNA was transcribed, fragmented, and 15 µg cRNA hybridized in triplicates for each of the three groups to the GeneChip arrays. Group1: CD3- CD56bright CD62L+,.Group2: CD3- CD56dim CD62L+, Group3: CD3- CD56dim CD62L-. Lists of differentially regulated genes were created using High Performance Chip Data Analysis (HPCDA) with Bioretis database (http://www.bioretis-analysis.de). Worldwide data sharing is possible via Bioretis, please ask the authors.
2010-05-28 | E-GEOD-21774 | biostudies-arrayexpress
Project description:Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's Digital Gene Expression (DGE) analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined using Real Time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared to sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height and crypt depth in jejunum and ileum compared to SBS animals. PDGF-α expression in crypts increased in SBS rats (vs sham) and was accompanied by increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with up-regulated PDGF-α receptor expression in the remaining small intestine. Animals were divided randomly into two experimental groups of 6 rats each. Group A rats underwent bowel transection and re-anastomosis (Sham), Group B animals underwent 75% bowel resection (SBS). Due to the quality of DNA, we performed final analysis from 5 jejunal samples (1 sham and 4 resected rats) and from 7 ileal samples (3 sham and 4 resected rats). Illumina's Digital Gene Expression (DGE) analysis using Illumina Rat Quad BeadChips was used to determine PDGF-related gene expression profiling.
2012-02-29 | E-GEOD-36122 | biostudies-arrayexpress
Project description:Study of the tetrapod limb has contributed a great deal to our understanding of developmental pathways and how changes to these pathways affect morphology. Most data on tetrapod limb development is known from amniotes, with far less known about genetic mechanisms of limb development in amphibians. To better understand the mechanisms of limb development in anuran amphibians, we use cyclopamine to inhibit Hedgehog signaling at various stages of limb development in Xenopus. We use transcriptomic analysis following cyclopamine exposure to understand the downstream effects of Hedgehog inhibition on gene expression. We find many aspects of Hedgehog function appear to be conserved with respect to amniotes, including the responses of ptc genes, gremlin, bmp2, and the autoregulatory property of shh. We show that, as was proposed based on experiments in chick, Sonic hedgehog plays two distinct roles in limb development â specification of digit number and specification of digit identity. In contrast to these points of conservation, we find that Hedgehog signaling is required for the maintenance of early limb bud outgrowth in Xenopus, a requirement not known for any other tetrapod. Experiment Overall Design: Eight microarray experiments were performed using RNA extracted from batches of hindlimbs dissected from Xenopus laevis tadpoles. Four of these were experimental groups exposed to cyclopamine at 1 µg/ml for 24 hours before animal fixation, and four were experimental groups exposed to the ethanol, the cyclopamine vehicle, at the same concentration used for cyclopamine vehicle for 24 hours. Each pool of RNA consisted of material from 18-22 hindlimb buds. Two experimental groups and two control groups were from one clutch of tadpoles, and the other four pools were from another clutch. Both samples within each of four paired groups (experimental vs. control) were exposed and processed simultaneously.
2008-10-18 | E-GEOD-8293 | biostudies-arrayexpress
Project description:Ewing Sarcoma is caused by a pathognomonic genomic translocation that places an N-terminal EWSR1 gene in approximation with one of several ETS genes (typically FLI1). This aberration, in turn, alters the transcriptional regulation of more than five hundred genes and perturbs a number of critical pathways that promote oncogenesis, cell growth, invasion, and metastasis. Among them, translocation-mediated up-regulation of the insulin-like growth factor receptor 1 (IGF-1R) and mammalian target of rapamycin (mTOR) are of particular importance since they work in concert to facilitate IGF-1R expression and ligand-induced activation, respectively, of proven importance in ES transformation. When used as a single agent in Ewing sarcoma therapy, IGF-1R or mTOR inhibition leads to rapid counter-regulatory effects that blunt the intended therapeutic purpose. Therefore, identify new mechanisms of resistance that are used by Ewing sarcoma to evade cell death to single-agent IGF-1R or mTOR inhibition might suggest a number of therapeutic combinations that could improve their clinical activity. Male non-obese diabetic (NOD)-SCID-IL-2Rgnull mice were used to generate EW5 explants (2 mm). Mice bearing subcutaneous tumors were randomized into treatment and control groups when their tumors reached a diameter of 6 mm and received MK-8669 (mTOR inhibitor, 5mg/kg per dose, once weekly), MK-0646 (IGF-1R inhibitor monoclonal antibody, 0.5mg IP twice weekly), or a placebo control (sterile buffer). Animals were treated either until their tumors reached 1500 mm3 in volume. Affymetrix Geneship profiling of EW5 xenografts treated in vivo either with MK-0646, MK-8669, and control and compared each other using extracted RNA and hybridized on Affymetrix microrrays ( Affymetrix Human Genome U133A 2.0 cartridge arrays).
2015-04-02 | E-GEOD-67529 | biostudies-arrayexpress
Project description:Background: Lyme borrelia genotypes differ in their capacity to cause disseminated disease. Gene array analysis was employed to profile the host transcriptome induced by Borrelia burgdorferi strains with different capacities for causing disseminated disease in the blood of C3H/HeJ mice during early infection. Results: Borrelia burgdorferi B515, a clinical isolate that causes disseminated infection in mice, differentially regulated 236 transcripts (P<0.05 by ANOVA, with fold change of at least 2). The 216 significantly induced transcripts included IFN-responsive genes and genes involved in immunity and inflammation. In contrast, B. burgdorferi B331, a clinical isolate that causes transient skin infection but does not disseminate in C3H/HeJ mice, stimulated changes in only a few genes (1 induced, 4 repressed). Transcriptional regulation of type I IFN and IFN-related genes was measured by quantitative RT-PCR in mouse skin biopsies collected from the site of infection 24 hours after inoculation with B. burgdorferi. The mean values for transcript of Ifnb, Cxcl10, Gbp1, Ifit1, Ifit3, Irf7, Mx1, and Stat2, were found to be significantly increased in B. burgdorferi strain B515-infected mice relative to the control group. In contrast, transcription of these genes was not significantly changed in response to B. burgdorferi strain B331 or B31-4, a mutant that is unable to disseminate. Conclusions: These results establish a positive association between the disseminating capacity of B. burgdorferi and early type I IFN induction in a murine model of Lyme disease.
2016-03-25 | E-MTAB-3325 | biostudies-arrayexpress
Project description:Salamanders, such as the Mexican axolotl, are some of the few vertebrates fortunate in their ability to regenerate diverse structures after injury. Unlike mammals they are able to regenerate a fully functional spinal cord after injury. However, the early signals required to initiate a pro-regenerative response after spinal cord injury is not well understood. To address this question we developed a spinal cord injury model in axolotls and used in vivo imaging of ion sensitive dyes and determined that spinal cord injury induces a rapid and dynamic change in the resting membrane potential of ependymoglial cells. Prolonged depolarization of ependymoglial cells after injury inhibits glial cell proliferation and subsequent axon regeneration. Using transcriptional profiling we identified c-Fos as a key voltage sensitive early response gene that is expressed specifically in the ependymoglial cells after injury. This data establishes that dynamic changes in the membrane potential after injury are essential for regulating the specific spatiotemporal expression of c-Fos that is critical for promoting faithful spinal cord regeneration in axolotl. All axolotls used in these experiments were bred in the axolotl facility at the University of Minnesota under the IACUC protocol #1201A08381. Axolotls of 2â3 cm were used for all in vivo experiments, and animals were kept in separate containers and fed daily with artemia; water was changed daily. Animals were anesthetized in 0.01% p-amino benzocaine (Sigma) before microinjection was performed. Experimental Design: Ivermectin injection Ivermectin or vehicle only (water) was pressure injected into the central canal of the spinal cord, and this was visualized by the addition of Fast Green into the solution. Directly after injection, a portion of the spinal cord was surgically removed and the animals were placed back into water in individual containers. One day post injury (1dpi) animals were anesthetized again and the area of the injury was removed. Tissue from 10 animals were pooled for each microarray replicate.
2016-07-05 | E-GEOD-71934 | biostudies-arrayexpress
Project description:12 wild-type C57BL/6 (B6) mice were divided into 4 groups: control group, IFN-α group, LPS group, and IFN-α+ LPS group, every group contained 3 mice (n=3). IFN-α was administrated i.p. to IFN-α group and IFN-α+ LPS group once daily (QD) for 7 days at a medium dose of 105units/kg weight, PBS was administrated i.p. to control group and LPS group QD for 7 days at the same volume. LPS group and IFN-α+ LPS group were injected i.v. with 10 μg LPS for one mouse on the 8th day. Control group and IFN-α group were injected i.v. with PBS at the same volume. 6 h later, mice were sacrificed to harvest spleens for protein microarray experiment. Mouse Cytokine Antibody Array 3(62) was purchased from Ray Biotech, Norcross GA, US. Protein microarray of murine cytokines expression. Spleens from 12 mice (4 group) were treated as indicated in the summary. Equal amount total protein from each spleen was pooled prior to gene expression analysis.
2012-11-10 | E-GEOD-42183 | biostudies-arrayexpress