Project description:It is often overlooked that human ESCs are generated from in vitro cultured, often surplus/‘discard’, embryos considered unsuitable for transfer in infertility clinics. In vitro culture of preimplantation embryos has been associated with a number of perturbations, including ultrastructure, gene expression, metabolism and post-transfer development. We report here the transcriptional profiles characteristic of ESC lines generated from either in vitro cultured or in vivo derived embryos. Embryonic stem cell RNAs were prepared from samples collected from 8 different lines. Four lines were generated from preimplantation embryos derived in vivo (R series; Thomson et al 1995) and four lines were generated from in vitro cultured preimplantation embryos (Ormes series; Mitalipov et al 2003). ChipInspector carries out significance analysis on the single probe level. Normalized probe set level data not provided for individual Sample records. Processed data is available on Series record.
Project description:It is often overlooked that human ESCs are generated from in vitro cultured, often surplus/‘discard’, embryos considered unsuitable for transfer in infertility clinics. In vitro culture of preimplantation embryos has been associated with a number of perturbations, including ultrastructure, gene expression, metabolism and post-transfer development. We report here the transcriptional profiles characteristic of ESC lines generated from either in vitro cultured or in vivo derived embryos.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:The goal of this study was to discover the underlying mechanisms that drive major changes in gene regulation during preimplantation development in the rhesus monkey. RNAseq data were collected from preimplantation stages (8-cell, morula, blastocyst), and used in conjunction with data from metaphase II stage oocytes to characterize individual gene expression profiles during preimplantation development, identify major groups of co-regulated genes, and identify likely upstream factors driving that gene regulation. Embryos were cultured following in vitro fertilization as described and lysed for analysis at specific stages.
Project description:Study question: What is the relative effect of common environmental and biological factors on transcriptome changes during human preimplantation development? Summary answer: Developmental stage and maternal age had a larger effect on the global gene expression profile of human preimplantation embryos than the culture medium or oxygen concentration used in in vitro culture. What is known already: Studies on mouse and bovine embryos have shown that different conditions in the in vitro culture of embryos can lead to changes in transcriptome profiles. For humans, an effect of developmental stage on the transcriptome profile of embryos has been demonstrated, but studies on the effect of maternal age or culture conditions are lacking. Participants/materials, setting, methods: Embryos that developed to morula or blastocyst stage during these 2 days whose amplified mRNA passed our quality control criteria for microarray hybridization were individually examined for genome-wide gene expression (N = 37). Main results and the role of chance: Based on the number of differentially expressed genes (DEGs), developmental stage (3519 DEGs) and maternal age (1258 DEGs) had a larger effect on the global gene expression profile of human preimplantation embryos than either tested culture medium (596 DEGs) or oxygen concentration (492 DEGs) used during in vitro culture. Interactions between the factors were found, indicating that culture conditions might have a different effect depending on the developmental stage or the maternal age of the embryos. Affected pathways included metabolism, cell cycle processes and oxidative phosphorylation. Limitations, reasons for caution: Culture of embryos for only 2 days might have limited the effect on global gene expression by the investigated culture conditions. Earlier stages of development (Day 0 until Day 4) were not analyzed and these embryos might respond differently to the experimental conditions. The freezing and thawing procedures might have had an effect on gene expression. RTâPCR validation was not performed due to scarcity of the material. Wider implications of the findings: Our results show that when studying gene expression in single human preimplantation embryos under various experimental conditions, one should take into account the confounding effect of biological variables, such as developmental stage and maternal age. This makes these experiments different from gene expression experiments where these variables can be tightly controlled, for example when using cell lines. Study design, size, duration: Donated, good quality, day 4 cryopreserved human preimplantation embryos (N = 89) were randomized to be cultured in one of two culture media (G5 medium or HTF medium) and one of two oxygen concentrations (5% or 20%), with stratification for maternal age. Next to these variables, developmental stage after culture was taken into account in the analysis.
Project description:Differential gene expression in preimplantation embryos has been documented, but few focused studies have been done to compare differential expression in human embryos after embryonic genome activation and specifically how they relate to blastocyst development. We hypothesized that blastocyst stage embryos would differentially express genes in pathways important in cell division, mobilization, and processes important in embryo implantation including endometrial apposition, adhesion, and invasion. We analyzed gene expression in 6 preimplantation human embryos. Embryos studied were previously cryopreserved, supernumerary human embryos donated by couples who completed their family building through in vitro fertilization and had given specific consent for use in research. Embryos cryopreserved at the pronuclear stage were thawed and cultured to cleavage (Day 3) or blastocyst (Day 5) stage. Differential gene expression was first obtained through Affymetrix gene expression microarrays and then validated both in silico using the Gene Expression Omnibus and in vitro with RT-qPCR. Compared to cleavage stage embryos, blastocyst stage embryos differentially expressed 51 genes (p < 0.001), with overrepresentation in amoebiasis pathways and pathways in cancer.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes