XGef Mediates Early CPEB Phosphorylation duringXenopusOocyte Meiotic Maturation

Polyadenylation-induced translation is an important regulatory mechanism during metazoan development. During Xenopus oocyte meiotic progression, polyadenylation-induced translation is regulated by CPEB, which is activated by phosphorylation. XGef, a guanine exchange factor, is a CPEB-interacting protein involved in the early steps of progesterone-stimulated oocyte maturation. We find that XGef influences early oocyte maturation by directly influencing CPEB function. XGef and CPEB interact during oogenesis and oocyte maturation and are present in a c-mos messenger ribonucleoprotein (mRNP). Both proteins also interact directly in vitro. XGef overexpression increases the level of CPEB phosphorylated early during oocyte maturation, and this directly correlates with increased Mos protein accumulation and acceleration of meiotic resumption. To exert this effect, XGef must retain guanine exchange activity and the interaction with CPEB. Overexpression of a guanine exchange deficient version of XGef, which interacts with CPEB, does not enhance early CPEB phosphorylation. Overexpression of a version of XGef that has significantly reduced interaction with CPEB, but retains guanine exchange activity, decreases early CPEB phosphorylation and delays oocyte maturation. Injection of XGef antibodies into oocytes blocks progesterone-induced oocyte maturation and early CPEB phosphorylation. These findings indicate that XGef is involved in early CPEB activation and implicate GTPase signaling in this process.

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H1foo is essential for in vitro meiotic maturation of bovine oocytes

Zygote ◽

10.1017/s0967199414000021 ◽

2014 ◽

Vol 23 (3) ◽

pp. 416-425 ◽

Cited By ~ 13

Author(s):

Yan Yun ◽

Peng An ◽

Jing Ning ◽

Gui-Ming Zhao ◽

Wen-Lin Yang ◽

...

Keyword(s):

Oocyte Maturation ◽

Polar Body ◽

Linker Histone ◽

Meiotic Maturation ◽

Control Group ◽

Bovine Oocyte ◽

First Polar Body ◽

Effective Sirnas ◽

Bovine Oocytes

SummaryOocyte-specific linker histone, H1foo, is localized on the oocyte chromosomes during the process of meiotic maturation, and is essential for mouse oocyte maturation. Bovine H1foo has been identified, and its expression profile throughout oocyte maturation and early embryo development has been established. However, it has not been confirmed if H1foo is indispensable during bovine oocyte maturation. Effective siRNAs against H1foo were screened in HeLa cells, and then siRNA was microinjected into bovine oocytes to down-regulate H1foo expression. H1foo overexpression was achieved via mRNA injection. Reverse transcription polymerase chain reaction (RT-PCR) results indicated that H1foo was up-regulated by 200% and down-regulated by 70%. Based on the first polar body extrusion (PB1E) rate, H1foo overexpression apparently promoted meiotic progression. The knockdown of H1foo significantly impaired bovine oocyte maturation compared with H1foo overexpression and control groups (H1foo overexpression = 88.7%, H1foo siRNA = 41.2%, control = 71.2%; P < 0.05). This decrease can be rescued by co-injection of a modified H1foo mRNA that has escaped from the siRNA target. However, the H1e (somatic linker histone) overexpression had no effect on PB1E rate when compared with the control group. Therefore we concluded that H1foo is essential for bovine oocyte maturation and its overexpression stimulates the process.

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Centrosome and microtubule dynamics during meiotic progression in the mouse oocyte

Journal of Cell Science ◽

10.1242/jcs.100.2.289 ◽

1991 ◽

Vol 100 (2) ◽

pp. 289-298 ◽

Cited By ~ 4

Author(s):

S.M. Messinger ◽

D.F. Albertini

Keyword(s):

Mouse Oocyte ◽

Meiotic Maturation ◽

Microtubule Nucleation ◽

Microtubule Organization ◽

Double Labeling ◽

Meiotic Progression ◽

Tubulin Antibodies ◽

Discrete Populations ◽

Meiosis I

The disposition, function and fate of centrosomes were analysed in mouse oocytes undergoing in vitro meiotic maturation, using multiple-label fluorescence microscopy. Oocytes fixed at various points during meiotic progression were double labeled with either human centrosome-specific antibody, 5051, and anti-tubulin antibodies or 5051 and MPM-2 antibodies in order to evaluate the microtubule nucleation capacity and phosphorylation status of centrosomes during this process. Double labeling with anti-tubulin antibodies revealed two populations of centrosomes that undergo stage-specific changes in number, location and microtubule nucleation capacity in relation to spindle assembly and cytoplasmic events. Specifically, one population was consistently associated with chromatin throughout meiotic maturation whereas a second population of cytoplasmic centrosomes exhibited maximal numbers and nucleation capacity at prometaphase and anaphase of meiosis-I. Quantitative evaluation of cytoplasmic centrosomes indicated increased numbers during the transition from diakinesis to prometaphase and metaphase to anaphase and total disappearance during telophase. Colocalization studies with MPM-2 revealed that centrosomes were always phosphorylated. However, at metaphase of meiosis I and II the microtubule nucleation capacity of centrosomes was diminished. These results suggest the existence of two discrete populations of centrosomes in the mouse oocyte that are coordinately regulated to subserve aspects of microtubule organization relative to both nuclear and cytoplasmic events.

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Effect of Hyaluronan on Developmental Competence and Quality of Oocytes and Obtained Blastocysts fromIn VitroMaturation of Bovine Oocytes

BioMed Research International ◽

10.1155/2014/519189 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Jolanta Opiela ◽

Joanna Romanek ◽

Daniel Lipiński ◽

Zdzisław Smorąg

Keyword(s):

Dna Fragmentation ◽

Oocyte Maturation ◽

Developmental Competence ◽

Meiotic Maturation ◽

Nuclear Maturation ◽

Significant Difference ◽

The Mean ◽

Bovine Oocytes

The objective of the present study was to evaluate the effect of hyaluronan (HA) during IVM on meiotic maturation, embryonic development, and the quality of oocytes, granulosa cells (GC), and obtained blastocysts. COCs were maturedin vitroin control medium and medium with additional 0.035% or 0.07% of exogenous HA. The meiotic maturity did not differ between the analysed groups. The best rate and the highest quality of obtained blastocysts were observed when 0.07% HA was used. A highly significant difference (P<0.001) was noted in the mean number of apoptotic nuclei per blastocyst and in the DCI between the 0.07% HA and the control blastocysts (P<0.01). Our results suggest that addition of 0.035% HA and 0.07% HA to oocyte maturation media does not affect oocyte nuclear maturation and DNA fragmentation. However, the addition of 0.07% HA during IVM decreases the level of blastocysts DNA fragmentation. Finally, our results suggest that it may be risky to increase the HA concentration during IVM above 0.07% as we found significantly higherBaxmRNA expression levels in GC cultured with 0.07% HA. The final concentration of HA being supplemented to oocyte maturation media is critical for the success of the IVP procedure.

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311EFFECT OF OOCYTE MATURATION MEDIA ON THE SPEED OF MEIOTIC PROGRESSION AND BLASTOCYST DEVELOPMENT OF BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab311 ◽

2004 ◽

Vol 16 (2) ◽

pp. 275

Author(s):

D. Fischer ◽

J. Bordignon ◽

C. Robert ◽

D. Betts

Keyword(s):

Embryo Development ◽

Oocyte Maturation ◽

Immunofluorescence Microscopy ◽

Chromosomal Abnormalities ◽

Culture Media ◽

Blastocyst Formation ◽

Blastocyst Development ◽

Nuclear Maturation ◽

Meiotic Progression

Environment is crucial for in vitro development of gametes and embryos. The recent progression of culture media towards defined conditions brought to surface the impact of different medium supplements on oocyte and embryo development. In this work we evaluate the effect of various oocyte culture media on bovine oocyte maturation and subsequent embryo development. Bovine cumulus-oocyte complexes were recovered from slaughterhouse ovaries and matured in vitro in either TCM-199 (Gibco) or SOF (Synthetic Oviduct Fluid) media supplemented with BSA (fatty acid-free) or serum (fetal bovine serum). Oocytes from each treatment group were denuded and fixed at 18, 20, 22, 24, 26 and 28h post-maturation (p.m.). Oocyte meiotic progression was monitored in each of the groups (n=28–40 oocytes/group) by immunofluorescence microscopy of chromatin. Oocytes matured in SOF showed a slower rate of meiotic progression when compared to the other groups, with the highest percentage of oocytes reaching the MII stage by 28h p.m. (60.71% SOF-BSA, 71.43% SOF-Serum). The fastest developmental rate was observed in oocytes matured in TCM-serum (77.15% at 24h p.m.) followed by oocytes matured in TCM-BSA (74.29% at 26h p.m.). In order to evaluate the effect of nuclear maturation on chromosome segregation, chromosomal organization of MII oocytes was evaluated by immunofluorescence microscopy within each media group (n=26–31 oocytes/group) at 18, 22 and 26h p.m.. No chromosomal abnormalities were found at 18h p.m.. Both media supplemented with BSA induced lower frequencies of chromosomal abnormalities (0 to 3.23%) and (3.57 to 7.69%) for SOF and TCM, respectively, when compared to their serum-supplemented counterparts (7.14 to 11.54%) and (10 to 10.71%) for SOF and TCM, respectively at 22 and 26h p.m.. Remarkably, the maturation medium and its supplements influenced the speed of blastocyst development. For this experiment, oocytes were matured in TCM-BSA, TCM-Serum, SOF-BSA or SOF-serum, fertilized in vitro in a TALP-base media supplemented with BSA and cultured in SOF-BSA. Blastocyst development was assessed at 7, 8 and 9 days of culture. Cleavage rates were similar between the groups (84–90%), whereas development rates to blastocyst stage varied among treatment groups. Maturation in SOF-BSA induced a delay in blastocyst formation that reached its highest percentage only on day 9 of culture (30.8%); moreover, blastocyst development was carried over until Day 12. When oocytes were matured in the presence of serum, the number of blastocysts did not increase after Day 8 of culture (26.6%, TCM-serum). These results provide evidence of a severe impact of oocyte culture media on the nuclear maturation of oocytes and their subsequent embryonic development after IVF. Moreover, the difference in the rate of oocyte maturation and blastocyst formation emphasizes the necessity for reviewing and adapting current protocols to new systems such as SOF-BSA. [Research funded by NSERC and OMAF of Canada.]

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Energy substrates and the completion of spontaneous meiotic maturation

Zygote ◽

10.1017/s0967199400001131 ◽

2000 ◽

Vol 8 (4) ◽

pp. 339-351 ◽

Cited By ~ 40

Author(s):

Stephen M. Downs ◽

Elliott D. Hudson

Keyword(s):

Cumulus Cell ◽

Suppressive Effect ◽

Meiotic Maturation ◽

Culture Volume ◽

Energy Substrate ◽

Meiotic Progression ◽

Culture Viability ◽

Effect Of Glucose ◽

Positive Effect

This study was carried out to examine how different combinations of pyruvate and glucose affect spontaneous meiotic maturation of cumulus-cell-enclosed mouse oocytes (CEO) to metaphase II (MII). Most experiments used an open system in which oocytes were cultured in 1 ml medium in plastic tubes. Initial experiments examined the dose response effects of pyruvate or glucose alone in the presence or absence of 2 mM glutamine. When medium lacked both pyruvate and glucose, more than 91% of the oocytes died in glutamine-free medium during 15 h of culture; viability was restored with the addition of glutamine, but only 11% of the CEO reached MII. In the absence of glutamine, 62–68% of oocytes completed maturation in 0.23–2.3 mM pyruvate, while 44–60% MII was observed in 0.55–27.8 mM glucose. The addition of glutamine to these cultures had a general suppressive effect on the completion of maturation. When glucose was added to pyruvate-containing cultures, the combination of 1 mM pyruvate/5.5 mM glucose was most effective in supporting maturation (about 90% MII), with little effect of glutamine. No further increase in maturation was observed when glucose was increased five-fold (to 27.8 mM). The positive effect of glucose was in part attributed to stimulation of glycolysis and increased production of pyruvate, since a reduced culture volume (8 μl), which allows the accumulation of secreted pyruvate, improved maturation in glucose-containing, but not pyruvate-containing, medium, and FSH, which stimulates glycolysis, increased progression to MII in glucose-containing, but not pyruvate-containing, medium. Yet these results also suggest that glucose has a beneficial effect on maturation apart from simple provision of pyruvate. The pyruvate effect was directly on the oocyte, because denuded oocytes responded more effectively than CEO to this energy substrate. The highest percentage of MII oocytes (96–97%) occurred in microdrop cultures containing glucose but lacking glutamine. These results indicate that glutamine supports oocyte viability but is not an adequate energy source for the completion of spontaneous meiotic maturation and may be detrimental. In addition, while pyruvate and glucose alone can each support meiotic progression of CEO to MII, optimal maturation requires the provision of both substrates to the culture medium when a large volume (1 ml) is used. It is concluded that careful attention to specific energy substrate supplementation and culture volume is important to optimise spontaneous meiotic maturation in vitro.

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Luteolin Orchestrates Porcine Oocyte Meiotic Progression by Maintaining Organelle Dynamics Under Oxidative Stress

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.689826 ◽

2021 ◽

Vol 9 ◽

Author(s):

Soo-Hyun Park ◽

Pil-Soo Jeong ◽

Ye Eun Joo ◽

Hyo-Gu Kang ◽

Min Ju Kim ◽

...

Keyword(s):

Oxidative Stress ◽

Oocyte Maturation ◽

Polar Body ◽

Blastocyst Formation ◽

Cortical Granules ◽

Expression Levels ◽

Meiotic Progression ◽

First Polar Body ◽

Underlying Mechanisms

Increasing evidence has demonstrated that oxidative stress impairs oocyte maturation, but the underlying mechanisms remain largely unknown. Here, for the first time, we examined the antioxidant role of luteolin in meiotic progression and the underlying mechanisms. Supplementation of 5 μM luteolin increased the rates of first polar body extrusion and blastocyst formation after parthenogenetic activation, and the expression levels of oocyte competence (BMP15 and GDF9)-, mitogen-activated protein kinase (MOS)-, and maturation promoting factor (CDK1 and Cyclin B)-related genes were also improved. Luteolin supplementation decreased intracellular reactive oxygen species levels and increased the expression levels of oxidative stress-related genes (SOD1, SOD2, and CAT). Interestingly, luteolin alleviated defects in cell organelles, including actin filaments, the spindle, mitochondria, the endoplasmic reticulum, and cortical granules, caused by H2O2 exposure. Moreover, luteolin significantly improved the developmental competence of in vitro-fertilized embryos in terms of the cleavage rate, blastocyst formation rate, cell number, cellular survival rate, and gene expression and markedly restored the competencies decreased by H2O2 treatment. These findings revealed that luteolin supplementation during in vitro maturation improves porcine meiotic progression and subsequent embryonic development by protecting various organelle dynamics against oxidative stress, potentially increasing our understanding of the underlying mechanisms governing the relationship between oxidative stress and the meiotic events required for successful oocyte maturation.

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Melatonin Protects Against Mdivi-1-Induced Abnormal Spindle Assembly and Mitochondrial Superoxide Production During Porcine Oocyte Maturation

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.693969 ◽

2021 ◽

Vol 9 ◽

Author(s):

Seul-Gi Yang ◽

Seung-Yeon Joe ◽

Jin-Wook Bae ◽

Gyeong-Deok Heo ◽

Hyo-Jin Park ◽

...

Keyword(s):

Oocyte Maturation ◽

Mitochondrial Function ◽

Mitochondrial Fission ◽

Spindle Assembly ◽

Meiotic Maturation ◽

Related Protein ◽

Atp Production ◽

Protein Levels ◽

Porcine Oocyte

Mitochondrial division inhibitor 1 (Mdivi-1) reportedly provides a close connection between oocyte maturation and mitochondrial function in pigs. N-acetyl-5-methoxy-tryptamine (melatonin) is known to be a representative antioxidant with the ability to rehabilitate meiotic maturation of porcine oocytes. However, the ability of melatonin to recover Mdivi-1-mediated disruption of spindle formation during meiotic maturation of porcine oocytes during in vitro maturation (IVM) has not been studied. Here, we first investigated changes in mitochondrial length, such as fragmentation and elongation form, in mature porcine oocytes during IVM. Mature oocytes require appropriate mitochondrial fission for porcine oocyte maturation. We identified a dose-dependent reduction in meiotic maturation in porcine oocytes following Mdivi-1 treatment (50, 75, and 100 μM). We also confirmed changes in mitochondrial fission protein levels [dynamin-related protein 1 phosphorylation at serine 616 (pDRP1-Ser616) and dynamin-related protein 1 (DRP1)], mitochondrial membrane potential, and ATP production in 75 μM Mdivi-1-treated oocytes. As expected, Mdivi-1 significantly reduced mitochondrial function and DRP1 protein levels and increased spindle abnormalities in porcine oocytes. In addition, we confirmed that melatonin restores abnormal spindle assembly and reduces meiotic maturation rates by Mdivi-1 during porcine oocyte maturation. Interestingly, the expression levels of genes that reduce DNA damage and improve tubulin formation were enhanced during porcine meiotic maturation. Taken together, these results suggest that melatonin has direct beneficial effects on meiotic maturation through tubulin formation factors during porcine oocyte maturation.

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191 SUPPLEMENTATION OF MATURATION MEDIUM WITH FOLLICULAR FLUID, EPIDERMAL GROWTH FACTOR AND NEUREGULIN AFFECTS MITOCHONDRIAL DNA REPLICATION, OOCYTE MATURATION AND EMBRYO DEVELOPMENT IN PIGS

Reproduction Fertility and Development ◽

10.1071/rdv24n1ab191 ◽

2012 ◽

Vol 24 (1) ◽

pp. 208

Author(s):

J. Mao ◽

K. M. Whitworth ◽

L. D. Spate ◽

E. M. Walters ◽

J. Zhao ◽

...

Keyword(s):

Growth Factor ◽

Embryo Development ◽

Oocyte Maturation ◽

Follicular Fluid ◽

Copy Number ◽

In Vitro Maturation ◽

Meiotic Maturation ◽

Mtdna Copy Number ◽

Maturation Medium

Mitochondria supply the majority of ATP in a cell. Mitochondrial DNA (mtDNA) copy number in oocytes might be used as a marker of viability and might be a key determinant of pre-implantation embryo development. However, little is known about mtDNA copy number changes during porcine oocyte maturation and its regulation by extracellular growth factors. The objectives of the current study were to determine the effects of supplementation of in vitro maturation medium with porcine follicular fluid (pFF; 0, 10, 20 and 30%), epidermal growth factor (EGF; 10 ng mL–1), neuregulin 1 (NRG; 20 ng mL–1) and NRG + IGF1 (insulin-like growth factor-1; 100 ng mL–1 + NRG, 20 ng mL–1) during in vitro maturation on mtDNA copy number, oocyte meiotic maturation and subsequent embryo development after parthenogenic activation. Follicular fluid used for the pFF supplementation experiment was prepared from medium-sized (3–6 mm in diameter) healthy follicles. Cumulus–oocyte complexes (COCs) were collected from antral follicles (3–6 mm in diameter), cultured in LH- and FSH-containing maturation medium for 22 h at 38.5°C, transferred into basic maturation medium without FSH and LH and cultured for another 22 h. The basic maturation medium was TCM-199 supplemented with 0.1% polyvinylalcohol (w/v), 3.05 mM D-glucose, 0.91 mM sodium pyruvate, 10 μg mL–1 of gentamicin, 0.57 mM cysteine and without or with different growth factors depending on the experimental design. In total, 177 germinal vesicle (GV) oocytes and 3837 MII oocytes were used for this study. All data were analyzed by the general linear model (GLM) procedure of SAS software (V9.2). The mtDNA copy number in oocytes increased (P < 0.05) from GV to MII stage oocytes (MII oocytes from all treatment groups pooled). Supplementation of IVM media with 10% pFF decreased mtDNA copy number (P < 0.05), whereas 20 and 30% pFF had no major effect on mtDNA copy number, resulting in a quadratic correlation between percentage of pFF and mtDNA copy number. There was a negative linear correlation between percentage of pFF and oocyte meiotic maturation, with a higher percentage of pFF inhibiting meiotic maturation (73.2 ± 5.2, 71.9 ± 4.8, 64.1 ± 8.5 and 65.8 ± 6.4% for 0, 10, 20 and 30% pFF groups, respectively). The mtDNA copy numbers in EGF and NRG-treated MII oocytes were significantly higher than those in GV oocytes, whereas the control was not different (EGF, 237 042.6 ± 22 198.2; NRG, 281 293.4 ± 22 893.5; and control, 231 856.8 ± 21 883.5 in MII oocytes vs 192 288.7 ± 21 675.4 in GV oocytes). The EGF, NRG and NRG+IGF1 treatments enhanced oocyte maturation as well. There was no difference in Day-7 blastocyst formation between EGF, NRG+IGF1 and the control, whereas the NRG treatment enhanced blastocyst formation as compared to the control (23.8 ± 2.4 vs 15.1 ± 2.1%; P < 0.05). This study demonstrated that there was an increase in mtDNA copy number during in vitro maturation. The EGF and NRG treatments stimulated mitochondria biogenesis, which may provide new means to increase oocyte quality and enhance embryonic development.

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172 THE APOPTOTIC EFFECTS OF BISPHENOL A-INDUCED MITOCHONDRIAL-DERIVED REACTIVE OXYGEN SPECIES ON MATURATION OF PORCINE OOCYTES IN VITRO

Reproduction Fertility and Development ◽

10.1071/rdv29n1ab172 ◽

2017 ◽

Vol 29 (1) ◽

pp. 194

Author(s):

S.-Y. Park ◽

H.-J. Park ◽

J.-W. Kim ◽

J.-Y. Park ◽

S.-G. Yang ◽

...

Keyword(s):

Oocyte Maturation ◽

Critical Role ◽

Cumulus Cell ◽

Cumulus Cells ◽

Meiotic Maturation ◽

Control Group ◽

Ros Production ◽

Maturation In Vitro ◽

Porcine Oocyte

Bisphenol A (BPA) is well known as oestrogen-like chemical and it is widely used in plastic products. Many studies have reported that BPA exposure has a well-known toxicity effect on reproduction function, such as reducing the number of ovulated oocytes, oocyte quality, and maturation rate. Recently, BPA induced mitochondrial-derived reactive oxygen species (mito-ROS) and disrupted mitochondrial homeostasis by increasing of superoxide anions production. In this study, we investigated how the regulation of mito-ROS production may play a critical role in meiotic maturation and expansion of cumulus cells during the in vitro maturation progression of porcine oocytes. Furthermore, we investigated the toxicity effect of BPA exposure on mitochondrial functions and mito-ROS production during porcine oocyte maturation in vitro. All results were analysed using a 1-way ANOVA followed by Bonferroni’s and Tukey’s Multiple Comparison Test and t-tests. First, porcine oocytes were matured in NCSU-23 medium supplemented with BPA (50, 75, and 100 µM) for 44 h. Our results indicated that the rates of matured oocytes were significantly decreased by BPA exposure in a dose-dependent manner (69.4 ± 5.1, 50.9 ± 6.3, and 29.9 ± 5.8% for BPA treatments of 50, 75, and 100 μM) compared with control group (70.2 ± 7.8%; P < 0.05). Next, we confirmed the secretion functions of oocyte and cumulus cell of cumulus-oocyte complex (COC) and ROS production. Cumulus cell secretion factors (has2, tnfaip6, and cx37) mRNA expression in COC were decreased in the BPA-treated (75 µM) group. In addition, mRNA expressions of mitochondrial-specific antioxidant enzymes (sod2, P < 0.001; prdx3, P < 0.01; prdx5, P < 0.001) and mitochondrial apoptosis genes (bax and caspase-3, P < 0.01) were significantly increased in COC of the BPA-treated (75 µM) group. We measured mitochondrial membrane potential and mito-ROS production using JC-1 analysis and Mito-SOX staining, respectively. The BPA treatment caused a rapid decrease of mitochondrial membrane potential maintenance and increase of mito-ROS production in porcine COC. Moreover, mitochondrial-specific ROS scavenger, Mito-Tempo (0.1 µM) treatment was significantly increased the meiotic maturation of porcine oocytes compared with control group (78.5 ± 3.5 v. 65.8 ± 5.0%; P < 0.05). Based on these results, we first confirmed that BPA exposure reduces the meiotic maturation and cumulus cells expansion of COC by increasing mito-ROS production during porcine oocyte maturation in vitro. Therefore, controlling of mito-ROS for mitochondrial function maintenance and apoptosis plays a critical role in improving porcine oocyte maturation in vitro. This work was supported by grants from the Next-Generation BioGreen 21 Program (PJ01117604) and the Bio-industry Technology Development Program (316037–04–1-HD020) through the Rural Development Administration, the Ministry of Agriculture, Food and Rural Affairs, Republic of Korea.

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207 GANGLIOSIDE IMPROVES THE MEIOTIC MATURATION AND ANTI-APOPTOTIC EFFECTS DURING IN VITRO MATURATION OF PORCINE OOCYTES

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab207 ◽

2016 ◽

Vol 28 (2) ◽

pp. 234

Author(s):

J.-W. Kim ◽

H.-J. Park ◽

S.-K. Chae ◽

J.-H. Ahn ◽

G.-Y. Do ◽

...

Keyword(s):

Oocyte Maturation ◽

Egf Receptor ◽

Untreated Group ◽

Meiotic Maturation ◽

Signal Molecules ◽

Developmental Potential ◽

Protein Levels ◽

Porcine Oocyte ◽

Apoptotic Effects

Gangliosides are sialic-acid-glycosphingolipids expressed in almost all vertebrate cells. These play a role in regulating cell differentiation and signal molecules of cellular signaling, including interactions with molecules of signal transduction pathways, such as receptors tyrosine kinases (RTK). Gangliosides perform critical functions through interactions with proteins as receptors in cell‐cell recognition, such as the epidermal growth factor (EGF) receptor (EGFR). Recent studies investigated functional a link between gangliosides-derived RTK signaling and embryo development until blastocyst in mice. However, there is no report on the directly relationship of GM3 or GD1a and oocyte maturation in pigs. Our studies have verified an interaction mechanism between EGF receptor signaling and gangliosides (GM3 and/or GD1a) in porcine oocyte during meiotic maturation and further development. The GM3 expression increased in mouse oocytes that were in vitro-matured (IVM) under apoptotic conditions. To induce the apoptotic conditions of oocytes, we used H2O2. We first confirmed that the expression of GM3 in oocytes of H2O2-treated groups (1 mM) was gradually increased compared with those of the control group (P < 0.05). We investigated the anti-apoptotic effect of GM3 as the inhibition apoptosis in porcine oocyte IVM by treatment of GM3 (5 or 10 μM) after pretreatment with H2O2. Next EGFR protein levels and meiotic maturation were investigated by Western blot analysis and acetic-orcerin staining, respectively, of IVM oocytes. The proportion of germinal vesicle arrested oocytes at 22 h was significantly increased (P < 0.05; 41.6 ± 1.5% v. 25.0 ± 0.0% in the untreated group) in EGF (10 ng mL–1) + GD1a (10 μM) treated group. To confirm the completion of meiotic maturation, we investigated the proportion of metaphase II (MII) oocytes at 44 h. The MII oocytes were increased (P < 0.05; 89.9 ± 3.6% v. 57.4 ± 5.3% in the untreated group) in oocytes cultured with EGF+GD1a. Interestingly, p-EGFR protein levels of matured oocytes were significantly increased (P < 0.05) by the EGF+GD1a treatment in the maturation process. In addition, EGF+GD1a treatment increased the proportion of normal pronucleus formation (2PN of 43.1 ± 5.2%) and increased (P < 0.05; 50.4 ± 6.1% v. 27.2 ± 2.7% in the untreated group) pre-implantation developmental potential until blastocyst. These results suggest that EGF+GD1a treatment improved the developmental competence of embryos via enhanced meiotic maturation of porcine oocytes by inducing EGFR activation. We confirmed that GM3 has anti-apoptotic effects during porcine oocyte maturation periods. Furthermore, these data will be helpful for better understanding the receptor mechanisms during oocyte maturation in pigs.

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