Gene expression profile of in vitro produced bovine blastocyst with and without Thyroid hormone supplementation
ABSTRACT: Bovine IVP blastocysts (day 8) were produced with and without thyroid hormones and gene expression profiles were compared. The IVC media (SOF) was supplemented with 50ng/ml of each T3 and T4. Four independent IVF run, each gave 1 control and 1 treated sample. Each sample is a pool of 5 blastocyst. Total Rna was extracted from each sample, amplified, labeled (also with dye swap) and hybridized to the EmbryoGene custom Agilent array (GPL13226). FlexArray software was used for data analysis.
Project description:Metabolic stress associated with negative energy balance in high producing dairy cattle and obesity in women is a risk factor for decreased fertility. Non-esterified fatty acids (NEFA) are involved in this pathogenesis as they jeopardize oocyte and embryo development. Growing evidence indicates that maternal metabolic disorders can disturb epigenetic programming, and more specifically DNA methylation, in the offspring. Final oocyte maturation and early embryo development coincide with specific methylation changes and both time periods are sensitive to adverse environments. Therefore, we investigated whether elevated NEFA concentrations affect the establishment and maintenance of DNA methylation patterns in oocytes and embryos and subsequently alter transcriptomic profiles and developmental competence of the resultant blastocysts. To do this, bovine oocytes and embryos were exposed to different NEFA concentrations in two separate experiments. In the first experiment, oocytes were matured in vitro for 24 hours in medium containing: 1) physiological (“BASAL”) concentrations of oleic (OA), palmitic (PA) and stearic (SA) or 2) elevated (pathophysiological or “HIGH COMBI”) concentrations of OA, PA and SA. In the second experiment, zygotes were cultivated in vitro for 6.5 days under BASAL or HIGH COMBI conditions. The developmental competence was evaluated by assessing cleavage and blastocyst rate. Overall gene expression and DNA methylation of resultant blastocysts were analyzed using microarray techniques. Data regarding DNA methylation were re-evaluated by pyrosequencing. HIGH COMBI-exposed oocytes and embryos displayed a lower competence to develop into blastocysts compared to their BASAL-exposed counterparts (19.3 % compared to 23.2 % and 18.2 % compared to 25.3 %, respectively) (P < 0.05). HIGH COMBI-exposed oocytes and embryos resulted in blastocysts with altered DNA methylation profiles and transcriptomic fingerprints, compared to BASAL-exposed counterparts. Differences in gene expression and methylation were more pronounced after exposure during culture compared to maturation suggesting that zygotes are more susceptible to an adverse environment. Main gene networks affected were related to lipid and carbohydrate metabolism, cell death, immune response and metabolic disorders. This may offer clues regarding the high rate of embryonic loss and metabolic diseases during later stages of life observed in offspring from mothers displaying lipolytic disorders. Two experiments were set up to characterize the epigenomic profile of the resultant day 7.5 blastocysts. In the first (in vitro maturation or IVM) experiment, the effect of elevated NEFA exposure during oocyte maturation (24 h) on DNA methylation profiles was evaluated by exposing oocytes to the BASAL or HIGH COMBI conditions. In the second (in vitro culture or IVC) experiment, the effect of elevated NEFA exposure during embryo culture (6.5 days) on DNA methylation marks was evaluated by exposing embryos to the BASAL or HIGH COMBI conditions. A total of 1039 and 1412 oocytes were used in the IVM and IVC experiment, respectively, equally distributed between treatments in 4 replicates. Resultant day 7.5 blastocysts were snap frozen for subsequent DNA methylation analysis (80 blastocysts in each experiments, equally collected between treatments in 4 replicates).
Project description:The process of early development of mammals is subtly and accurately controlled by the regulation networks of embryo cells. Time course expression data measured at different stages during early embryo development process can give us valuable information by revealing the dynamic expression patterns of genes in genome wide scale. In this study, bovine embryo expression data were generated at oocyte, one cell stage, two cell stage, four cell stage, eight cell stage, sixteen cell stage, morula, and blastocyst; Human embryo expression data were generated at one cell stage, two cell stage, four cell stage, eight cell stage, morula, and blastocyst; Mouse embryo expression data were generated at one cell stage, two cell stage, four cell stage, eight cell stage, morula, and blastocyst. Experiment Overall Design: Bovine, Human, and Mouse embryos were harvested at successive stage from oocyte to blastocyste. Total RNAs were extracted, amplified and hybridized onto Affymetrix microarrays.
Project description:Developmental competences of oocytes derived from prepubertal heifers are lower than those derived from adult counterparts. The objective of this study was to identify a range of genes associated with reduced oocyte competence that are differentially expressed between adult versus prepubertal donors. Microarray experiments were conducted using total RNA isolated from GV and MII stages oocytes collected from adult and prepubertal animals using Affymetrix GeneChip Bovine Genome Array containing 24,072 probe sets representing over 23,000 transcripts. A total of 549 and 333 genes were differentially expressed between prepubertal versus adult bovine MII and GV stages oocytes respectively. Out of these, 312 and 176 genes were up-regulated, while 237 and 157 were down-regulated in prepubertal when compared with adult MII and GV oocytes respectively. Ontological classification of the differentially expressed genes revealed that up-regulated genes in adult oocytes were involved in signal transduction, regulation of transcription DNA-dependent, and transport. Results from the present study indicated that significant number of genes were differentially expressed (>2-fold, p<0.01) between the two groups. Thus the decreased developmental competence of oocytes from prepubertal heifers may be induced due to difference in gene expression abundance as observed in our study. In conclusion, transcript abundance analyses of oocytes using microarray approach have been carried out in bovine and several other species. However, to our knowledge, this is the first study carried out to examine genes expression differential abundance in oocytes derived from perpubertal versus adult Japanese Black Cattle. Bovine 4b PP biological rep1, Bovine 78b PP biological rep2, Bovine 79 PP biological rep3 represents GV stage oocytes derived from Prepubertal (PP) heifer group, while Bovine 74b A biological rep1, Bovine 80b A biological rep2, Bovine 81 A biological rep3 represents GV stage oocytes derived from Adult (A) cow group. Bovine 7 PP biological rep1, Bovine 53 PP biological rep2, Bovine 57 PP biological rep3 represents MII stage oocytes derived from Prepubertal heifer group, while Bovine 59 A biological rep1, Bovine 70 A biological rep2, Bovine 71 A biological rep3 represents MII stage oocytes from Adult cow group. The ovaries of adult cows (Japanese black cattle) were collected from local abattoir while ovaries of prepubertal Japanese black heifers (9 to 12 months old) were collected by spay device at several commercial farms. The collected ovaries of both the adult cows and prepubertal heifers groups were transported to the research laboratory in 0.67% (w/v) NaCl solution containing 100 mg/L kanamycin sulfate (Meiji Seika, Tokyo, Japan). For both groups, cumulus oocyte complexes (COCs) from ovarian follicles 2 to 8 mm in diameter were aspirated by using an 18 gauge needle (Terumo co, Tokyo, Japan) attached to a 5 ml disposable syringe (Nipro, Osaka, Japan). After collection, the COCs were washed twice with Tyrode-lactate-pyruvate-polyvinylalcohol (Hepes-TLP-PVA) and TCM 199 (Invitrogen, Gibco, NY, USA) supplemented with 10% heat-inactivated fetal bovine serum (maturation medium). Only COCs with evenly granulated cytoplasm surrounded by multiple layers of compact cumulus cells were used in all the experiments. The COCs (70 to 80) were placed in 200 µL drop of the maturation medium in petri dish (35x10mm, Becton Dickinson Labware, Oxnard, CA, USA) covered with paraffin liquid (Nacalai Tesque Inc, Kyoto, Japan) and cultured at 38.5°C in a humidified atmosphere of 5% CO2 in air for 20 to 22 h for maturation.
Project description:Mono(2-ethylhexyl) phthalate (MEHP), the main di(2-ethylhexyl) phthalate (DEHP) metabolite, is a known reproductive toxicant. Residual levels of 20 nM MEHP have been found in follicular fluid aspirated from IVF-treated women and DEHP-treated animals. It is not yet clear whether these residual MEHP levels have any effect on the follicle-enclosed oocyte or developing embryo. To clarify this point, bovine oocytes were matured with or without 20 nM MEHP for 22 h. Microarray analysis was performed for both mature oocytes and 7-day blastocysts. A feasibility examination was performed on mature oocytes (n = 200/group) to reveal a possible direct effect on the oocyte proteomic profile. Transcriptome analysis revealed MEHP-induced alterations in the expression of 456 and 290 genes in oocytes and blastocysts, respectively. The differentially expressed genes are known to be involved in various biological pathways, such as transcription process, cytoskeleton regulation and metabolic pathway. Among these, the expression of 9 genes was impaired in both oocytes exposed to MEHP (i.e., direct effect) and blastocysts developed from those oocytes (i.e., carryover effect). In addition, 191 proteins were found to be affected by MEHP in mature oocytes. The study explores, for the first time, the risk associated with exposing oocytes to physiologically relevant MEHP concentrations to the maternal transcripts. Although it was the oocytes that were exposed to MEHP, alterations carried over to the blastocyst stage, following embryonic genome activation, implying that these embryos are of low quality.
Project description:Transposable elements (TEs) are widely represented in eukaryotic genomes. Recently, a set of small RNAs known as rasRNAs (repeat-associated small RNAs) have been related to the down-regulation of TEs conferring a means to safeguard genome integrity. Two key members of the rasRNAs group are piRNAs and endo-siRNAs. In this study, we have performed a comparative analysis of piRNAs and endo-siRNAs present in mouse oocytes, spermatozoa and zygotes, identified by deep sequencing and bioinformatic analysis. Both piRNAs and endo-siRNAs regulate TEs in addition to other repetitive elements such as tRNAs and rRNAs, suggesting an alternative role of rasRNAs with regard to translation regulation. The detection of piRNAs and endo-siRNAs in sperm cells and revealed also in zygotes, hints to their potential delivery to oocytes during fertilization. However, a comparative assessment of the three cell types indicates that both piRNAs and endo-siRNAs are mainly maternally inherited. Finally, we have assessed the role of the different rasRNA molecules in connection with amplification processes by way of the “ping-pong cycle”. Our results suggest that the ping-pong cycle can act on other rasRNAs, such as tRNA- and rRNA-derived fragments, thus not only being restricted to TEs during gametogenesis, as was evidenced in spermatozoa, oocytes and zygotes. Comparative analysis from deep sequencing of piRNAs and endo-siRNAs in mouse oocytes, spermatozoa and zygotes
Project description:In order to establish an obese mouse model, female mice were continuously fed with a high-fat diet (HFD) or a normal diet (control) for 16 weeks beginning at three weeks of age. In this paper, these mice are termed ‘HFD mice’ and ‘control mice’, respectively. Accordingly, we call their oocytes ‘HFD oocytes’ and ‘control oocytes’. Substantial evidence indicates that the effects of maternal obesity on embryo/offspring development can be attributed to factors within the oocyte (9). To identify such potential effectors, we performed a comparative proteomic analysis of ovulated MII oocytes from control and HFD mice.
Project description:In cattle, almost all fully grown vesicle stage oocytes (GV) have the ability to resume meisos, develop to Metaphase II stage (MII), support fertilization and progress through the early embryonic cycles in vitro. Yet without intensive selection, the majority fail to develop to the blastocyst stage. Using the Affymetrix Bovine Genome Array, global mRNA expression analysis of immature (GV) and in vitro matured (IVM) bovine oocytes was carried out to characterize the transcriptome of the bovine oocyte and to identify the key pathways associated with oocyte meiotic maturation and developmental potential. Immature and in vitro matured bovine oocytes were collected for RNA extraction and hybridization on Affymetrix GeneChip Bovine Genome array. Careful removal of cumulus and selection of oocytes was carried out under the stereo microscope in order to examine the actual cumulus-free temporal oocyte gene expression profiles. Immature oocytes at time 0 h and in vitro matured oocytes at 24 h were collected for analysis.
Project description:Transcriptome (total RNA) profiling of bovine in vitro cultured expanded blastocysts (EB) comparing control non-treated expanded blastocysts with SAM-treated expanded blastocysts. S-Adenosyl methionine (SAM) is the global methyl donor providing methyl group for variety of biomolecules such as DNA , histone, RNA, lipids and etc. Two-condition experiment, bovine non-treated expanded blastocysts (pools of 10) vs bovine SAM-treated expanded blastocysts. Four biological replicates of each tissue were hybridized to four two-color arrays in a dye-balanced design.
Project description:The process of early development of mammals is subtly and accurately controlled by the regulation networks of embryo cells. Time course expression data measured at different stages during early embryo development process can give us valuable information by revealing the dynamic expression patterns of genes in genome wide scale. In this study, bovine embryo expression data were generated at oocyte, one cell stage, two cell stage, four cell stage, eight cell stage, sixteen cell stage, morula, and blastocyst. By comparing this data set with data generated with similar process on other species, we can study the trascriptom under a revolutionary scheme. Keywords: time course Bovine embryos were harvested at successive stage from oocyte to blastocyste. Total RNAs were extracted, amplified and hybridized onto Affymetrix microarrays.
Project description:Physiological changes underlying high density stress were examined in Oryza sativa plants over the course of a life cycle by assessing differences in gene expression. Moreover, the nitrogen limitation was examined in parallel with high density stress to gain a better understanding of physiological responses specific to high density stress. RNA was extracted from 21 and 31 days old plants. The plants were grown under four conditions: sufficient nitrogen (10mM N) and low density (six plants per bin), limiting nitrogen (3mM N) and low density, sufficient nitrogen and high density (40 plants per bin), limiting nitrogen and high density. Three biological replicates were sampled from each growth condition.