bims-gamemb 2021-12-05 papers

bims-gamemb

Biomed News

on Gamete and embryo metabolism

Issue of 2021–12–05
eleven papers selected by
Cameron A. Schmidt, East Carolina University

Embryonic hyperglycemia perturbs the development of specific retinal cell types, including photoreceptors.
Effects of NEFAs during IVM on pig embryos from granulosa cell-cocultured oocytes.
Raman Spectrum of Follicular Fluid: A Potential Biomarker for Oocyte Developmental Competence in Polycystic Ovary Syndrome.
MITOCHONDRIA-TARGETED COMPOUNDS TO ASSESS AND IMPROVE HUMAN SPERM FUNCTION.
Paraquat exposure impairs porcine oocyte meiotic maturation.
Optimization of dissolved oxygen levels in extender prevents development of cryocapacitation like changes, oxidative stress and augments zona binding capacity of crossbred bull spermatozoa.
Follicle-stimulating hormone mediates the consumption of serum-derived glycogen by bovine cumulus-oocyte complexes during in vitro maturation.
Follicular development, morphological integrity, and oxidative stress in bovine preantral follicles cultured in vitro with ascorbic acid.
Effects of individual or in-combination antioxidant supplementation during in vitro maturation culture on the developmental competence and quality of porcine embryos.
CWIN-sugar transporter nexus is a key component for reproductive success.
Alterations in epididymal sperm maturation caused by ageing.

J Cell Sci. 2021 Dec 01. pii: jcs.259187. [Epub ahead of print]

Embryonic hyperglycemia perturbs the development of specific retinal cell types, including photoreceptors.

Kayla F Titialii-Torres, Ann C Morris.

  Diabetes is linked to various long-term complications in adults, such as neuropathy, nephropathy, and diabetic retinopathy. Diabetes poses additional risks for pregnant women, because glucose passes across the placenta, and excess maternal glucose can result in diabetic embryopathy. While many studies have examined the teratogenic effects of maternal diabetes on fetal heart development, little is known about the consequences of maternal hyperglycemia on the development of the embryonic retina. To address this question, we investigated retinal development in two models of embryonic hyperglycemia in zebrafish. Strikingly, we found that hyperglycemic larvae displayed a significant reduction in photoreceptors and horizontal cells, whereas other retinal neurons were not affected. We also observed reactive gliosis and abnormal optokinetic responses in hyperglycemic larvae. Further analysis revealed delayed retinal cell differentiation in hyperglycemic embryos that coincided with increased reactive oxygen species (ROS). Our results suggest that embryonic hyperglycemia causes abnormal retinal development via altered timing of cell differentiation and ROS production, which is accompanied by visual defects. Further studies using zebrafish models of hyperglycemia will allow us to understand the molecular mechanisms underlying these effects.

Keywords:  Diabetes; Hyperglycemia; Photoreceptors; Retina; Zebrafish

DOI:  https://doi.org/10.1242/jcs.259187
Mol Reprod Dev. 2021 Nov 28.

Effects of NEFAs during IVM on pig embryos from granulosa cell-cocultured oocytes.

Meihong Shi, Marc-André Sirard.

  Circulating levels of nonesterified fatty acids (NEFAs) are elevated in some females, which can impair oocyte maturation and embryo development, and may alter the phenotype of the progeny. However, the effects of NEFAs on human embryo development are not clear due to ethical limitations. Thus, we used pig as the model to investigate the impacts of NEFAs on oocyte and embryo due to their similar reproductive and metabolic physiologies to humans. In this study, porcine cumulus-oocyte complexes were in vitro maturated under a pathologically high concentration of NEFAs (468 μM palmitic acid, 194 μM stearic acid, and 534 μM oleic acid) with the presence of granulosa cell monolayer, in contrast to control without NEFAs. The mature oocytes were fertilized to produce embryos for further analysis of the transcriptome and DNA methylation patterns. The elevated level of NEFAs decreased the blastocyst rate and delayed the blastocyst development. Ingenuity pathway analysis showed that the most affected gene pathways were related mainly to cell activities, metabolism, and inflammation. These findings indicated that oocytes exposed to the exogenous high level of NEFAs during in vitro maturation resulted in altered gene expression and DNA methylation of early embryos, which have detrimental impacts on blastocyst quality.

Keywords:  DNA methylation; NEFAs; granulosa cell; pig embryo; transcriptome

DOI:  https://doi.org/10.1002/mrd.23548
Front Cell Dev Biol. 2021 ;9 777224

Raman Spectrum of Follicular Fluid: A Potential Biomarker for Oocyte Developmental Competence in Polycystic Ovary Syndrome.

Xin Huang, Ling Hong, Yuanyuan Wu, Miaoxin Chen, Pengcheng Kong, Jingling Ruan, Xiaoming Teng, Zhiyun Wei.

  Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive women where abnormal folliculogenesis is considered as a common characteristic. Our aim is to evaluate the potential of follicular fluid (FF) Raman spectra to predict embryo development and pregnancy outcome, so as to prioritize the best promising embryo for implantation, reducing both physiological and economical burdens of PCOS patients. In addition, the altered metabolic profiles will be identified to explore the aetiology and pathobiology of PCOS. In this study, follicular fluid samples obtained from 150 PCOS and 150 non-PCOS women were measured with Raman spectroscopy. Individual Raman spectrum was analyzed to find biologic components contributing to the occurrence of PCOS. More importantly, the Raman spectra of follicular fluid from the 150 PCOS patients were analyzed via machine-learning algorithms to evaluate their predictive value for oocyte development potential and clinical pregnancy. Mean-centered Raman spectra and principal component analysis (PCA) showed global differences in the footprints of follicular fluid between PCOS and non-PCOS women. Two Raman zones (993-1,165 cm-1 and 1,439-1,678 cm-1) were identified for describing the largest variances between the two groups, with the former higher and the latter lower in PCOS FF. The tentative assignments of corresponding Raman bands included phenylalanine and β -carotene. Moreover, it was found that FF, in which oocytes would develop into high-quality blastocysts and obtain high clinical pregnancy rate, were detected with lower quantification of the integration at 993-1,165 cm-1 and higher quantification of the integration at 1,439-1,678 cm-1 in PCOS. In addition, based on Raman spectra of PCOS FF, the machine-learning algorithms via the fully connected artificial neural network (ANN) achieved the overall accuracies of 90 and 74% in correctly assigning oocyte developmental potential and clinical pregnancy, respectively. The study suggests that the PCOS displays unique metabolic profiles in follicular fluid which could be detected by Raman spectroscopy. Specific bands in Raman spectra have the biomarker potential to predict the embryo development and pregnancy outcome for PCOS patients. Importantly, these data may provide some valuable biochemical information and metabolic signatures that will help us to understand the abnormal follicular development in PCOS.

Keywords:  Raman spectroscopy; biomarker; embryo development; machine learning; metabolic profiles; polycystic ovary syndrome (PCOS)

DOI:  https://doi.org/10.3389/fcell.2021.777224
Antioxid Redox Signal. 2021 Nov 30.

MITOCHONDRIA-TARGETED COMPOUNDS TO ASSESS AND IMPROVE HUMAN SPERM FUNCTION.

Sara Escada-Rebelo, Maria Inês Cristo, Joao Ramalho-Santos, Sandra Amaral.

SIGNIFICANCE: Currently 10-15% of couples in reproductive age face infertility issues. More importantly, male factor contributes to 50% of these cases (either alone or in combination with female causes). Amongst various reasons, impaired sperm function is the main cause for male infertility. Furthermore, mitochondrial dysfunction and oxidative stress due to increased ROS production, particularly of mitochondrial origin, are believed to be main contributors. Recent Advances: Mitochondrial dysfunction, particularly due to increased ROS production, has often been linked to impaired sperm function/quality. For decades different methods and approaches have been developed to assess mitochondrial features that might correlate with sperm functionality. This connection is now completely accepted, with mitochondrial functionality assessment used more commonly as a readout of sperm functionality. More recently, mitochondria-targeted compounds are on the frontline for both assessment as well as therapeutic approaches.
CRITICAL ISSUES: In this review we summarize the current methods for assessing key mitochondrial parameters known to reflect sperm quality as well as therapeutic strategies using mitochondrial-targeted antioxidants aiming to improve sperm function in various situations, particularly after sperm cryopreservation.
FUTURE DIRECTIONS: Although more systematic research is needed, mitochondrial-targeted compounds definitely represent a promising tool to assess as well as to protect and improve sperm function.

DOI: https://doi.org/10.1089/ars.2021.0238
Theriogenology. 2021 Nov 21. pii: S0093-691X(21)00428-3. [Epub ahead of print]179 60-68

Paraquat exposure impairs porcine oocyte meiotic maturation.

Naru Zhou, Qiuchen Liu, Xin Qi, Xiangdong Zhang, Zhenyuan Ru, Yangyang Ma, Tong Yu, Mianqun Zhang, Yunsheng Li, Yunhai Zhang, Zubing Cao.

  Paraquat (PQ) is a heterocyclic pesticide that not only damages the testicular development and reduces the quality of semen, but also disturbs the secretion of hormones in the reproductive system. However, the effects of PQ on oocyte maturation and its toxic mechanism have not been yet fully clarified. Here we showed that PQ exposure could have toxic effects on porcine oocyte maturation. PQ exposure with 100 μM inhibited cumulus cell expansion and significantly reduced the rate of first polar body extrusion during oocyte maturation. PQ-exposed oocytes could not develop to the 2-cell and blastocyst stage. PQ exposure with 100 μM significantly increased abnormal spindle rate (65.2% ± 1.0%) and misaligned chromosome rate (63.2% ± 3.4%) compared to the control group (38.3% ± 1.0% and 38.4% ± 1.0%, respectively; P < 0.05). F-actin also exhibited reduced distribution in PQ-exposed oocytes (10.3% ± 1.0%) compared to the control group (14.4% ± 1.0%, P < 0.05). In addition, PQ exposure reduced the active mitochondria levels, but apparently increased the reactive oxygen species (ROS), rH2AX, and LC3 (autophagy marker) levels. qPCR analyses showed that PQ exposure caused the aberrant expression of genes associated with cumulus cell expansion, but did not affect the expression of apoptosis-related genes. Taken together, these results indicate that PQ exposure impaired oocyte nuclear and cytoplasmic maturation probably through oxidative stress.

Keywords:  Autophagy; Oocyte maturation; Oxidative stress; Paraquat; Pig

DOI:  https://doi.org/10.1016/j.theriogenology.2021.11.018
Andrologia. 2021 Dec 01. e14331

Optimization of dissolved oxygen levels in extender prevents development of cryocapacitation like changes, oxidative stress and augments zona binding capacity of crossbred bull spermatozoa.

Abdul-Rahman Mustapha, Subrata Kumar Ghosh, Jai Kishan Prasad, Rahul Katiyar, Abhishek Kumar, Beigh Y Amin, Sadhan Bag, Sanjeev K Bhure, Guttula Taru Sharma, Med Ram Verma.

  The present study was undertaken to determine the efficacy of partial deoxygenation of extender at constant temperature (35°C) in freezability of crossbred bull semen. The dissolved oxygen (DO) levels were reduced by the use of newly developed technique of nitrogen effervescence at a flow rate of 2-3 bubbles per second. Four different levels of oxygen in semen extender, that is 11.7, 2, 4 and 8 ppm as control (Group-I), Group-II, Group-III and Group-IV, respectively, were used to assess the effect of partial deoxygenation on semen quality parameters. The 4 ppm level of DO resulted in higher (p < 0.05) progressive motility in comparison with non-treated group at post-thaw stage, whereas reduction up to 2 ppm resulted in drastic fall in motility. Oxidative stress status revealed low superoxide dismutase (SOD) and total antioxidant capacity (TAC) in Group-II, whereas higher (p < 0.05) SOD and TAC activities were observed in Group-III in comparison with non-treated group at pre-freeze and post-thaw stages. The sperm-zona binding at 4 ppm level of DO was significantly higher than control group, 2 and 8 ppm levels of DO. In conclusion, reduction of DO in the extender up to 4 ppm reduced oxidative stress and improved in vitro fertility of crossbred bull spermatozoa.

Keywords:  crossbred bull; dissolved oxygen; oxidative stress; semen; zona binding

DOI:  https://doi.org/10.1111/and.14331
Vet World. 2021 Sep;14(9): 2512-2517

Follicle-stimulating hormone mediates the consumption of serum-derived glycogen by bovine cumulus-oocyte complexes during in vitro maturation.

Ludymila F Cantanhêde, Cristiane T Santos-Silva, Marcelo T Moura, José C Ferreira-Silva, Júnior M B Oliveira, Daniel N A Gonçalves, Álvaro A C Teixeira, Valéria Wanderley-Teixeira, Marcos A L Oliveira.

   Background and Aim: Oocyte in vitro maturation (IVM) is an appealing approach for several assisted reproductive technologies and dissecting oocyte maturation. Nonetheless, IVM leads to lower developmental competence and usually relies on undefined, serum-containing media. Therefore, biochemical profiling aimed to explore fluctuations in IVM media content during the acquisition of oocyte developmental competence.
Materials and Methods: Bovine cumulus-oocyte complexes (COCs) underwent IVM in TCM199 medium with Earle's salts, supplemented with 2.0 mM L-glutamine, 10% fetal bovine serum, antibiotics, and 0.05 IU/mL porcine follicle-stimulating hormone (FSH+) or vehicle control (CTL) medium for 22 h.
Results: FSH withdrawal (CTL) diminished several processes associated with the acquisition of oocyte developmental competence, such as reduced cumulus cell expansion, diminished estradiol synthesis (FSH+: 116.0±0.0 pg/mL vs. CTL: 97.6±18.0 pg/mL), and lower oocyte nuclear maturation rate (FSH+: 96.47% vs. CTL: 88.76%). Fresh media formulations (i.e., TCM199 with FSH or vehicle) were indistinguishable under biochemical profiling threshold conditions. Biochemical profiling showed similar total protein and lipid concentrations between groups. Further, total sugar concentrations diminished from fresh media to their post-IVM counterparts, albeit in an FSH-independent manner. Glycogen concentrations remained unaltered after IVM within CTL media, albeit were substantially lower after IVM under FSH+ conditions.
Conclusion: FSH mediates the consumption of serum-derived glycogen by bovine COCs during IVM and implies that serum-free media should contain increased glucose concentrations to facilitate the acquisition of oocyte developmental competence.

Keywords:  biomolecules; cattle; developmental competence; gonadotropin; granulosa; sera

DOI:  https://doi.org/10.14202/vetworld.2021.2512-2517
Zygote. 2021 Dec 02. 1-7

Follicular development, morphological integrity, and oxidative stress in bovine preantral follicles cultured in vitro with ascorbic acid.

Larissa Zamparone Bergamo, Denis Vinicius Bonato, Camila Bizarro-Silva, Francieli Gesleine Capote Bonato, Tamires Korchovei Sanches, Marcela Bortoletto Cerezetti, Ana Carolina Rossaneis, Waldiceu A Verri, Fábio Morotti, Marcelo Marcondes Seneda.

  The aim of this study was to evaluate the follicular development, morphological integrity, and oxidative stress of preantral ovarian follicles from Bos taurus indicus females grown in vitro with ascorbic acid. Ovaries (n = 20) from Bos taurus indicus females were collected, fragmented, and were cultured in vitro for 6 or 12 days in minimum essential medium (MEM), or MEM supplemented with 50 or 100 ng/ml ascorbic acid, with an extracellular matrix of agarose gel, in an incubator at 38.5°C; every 2 days, 100% of the culture medium was replaced. The data were analyzed using the chi-squared test and/or Fisher's exact test. In the event of a significant effect, the proportions were compared using a 2 × 2 proportion test. The oxidative stress analysis data were submitted to analysis of variance followed by the Bonferroni test. Values were considered significant when P ≤ 0.05. The addition of 100 ng/ml of ascorbic acid to the in vitro culture medium of preantral ovarian follicles from bovine females promoted follicular development, was efficient in maintaining morphological integrity, as well as the stability of reactive oxygen species, after 6 days of in vitro culture.

Keywords:  Bos taurus indicus; FRAP; NBT; Reactive oxygen species; TBARS

DOI:  https://doi.org/10.1017/S0967199421000903
Reprod Domest Anim. 2021 Dec 04.

Effects of individual or in-combination antioxidant supplementation during in vitro maturation culture on the developmental competence and quality of porcine embryos.

Chommanart Thongkittidilok, Quynh Anh Le, Qingyi Lin, Koki Takebayashi, Lanh Thi Kim Do, Zhao Namula, Maki Hirata, Fuminori Tanihara, Takeshige Otoi.

  The oocyte maturation process requires a high supply of energy, which generates reactive oxygen species (ROS), adversely affecting oocyte and embryo development. Balancing ROS by antioxidant supplementation is essential for maintaining oocyte maturation and embryonic quality in vitro. This study aimed to evaluate the impact of four antioxidants: β-mercaptoethanol (β-ME), chlorogenic acid (CGA), curcumin, and sericin, when applied individually or in combinations, during oocyte maturation on development of porcine oocytes. Cumulus-oocyte complexes were collected, cultured in maturation medium supplemented with antioxidants for 44 h, and subsequently subjected to in vitro fertilisation (IVF) and culture for 7 days. Combining all four (β-ME+CGA+curcumin+sericin) or three (β-ME+CGA+curcumin) antioxidants increased blastocyst formation rates. However, sericin supplementation alone, or in combination with β-ME or CGA, failed to improve blastocyst formation rates. The total cell numbers of blastocysts from the group supplemented with three antioxidants (β-ME+CGA+curcumin) were significantly higher than those from the other groups, except for the curcumin-supplement group. There were no differences in the maturation rates and proportions of oocytes with fragmented DNA between the antioxidant-supplemented and the non-supplemented control groups. In conclusion, supplementation with three antioxidants (β-ME+CGA+curcumin) during the maturation culture enhanced blastocyst formation and improved blastocyst quality.

Keywords:  antioxidant; development; maturation; porcine embryo; quality

DOI:  https://doi.org/10.1111/rda.14063
J Plant Physiol. 2021 Nov 18. pii: S0176-1617(21)00211-X. [Epub ahead of print]268 153572

CWIN-sugar transporter nexus is a key component for reproductive success.

Yong-Ling Ruan.

  Reproductive development is critical for completion of plant life cycle and realization of crop yield potential. Reproductive organs comprise multiple distinctive or even transgenerational tissues, which are symplasmically disconnected from each other for protection and better control of nutrition and development. Cell wall invertases (CWINs) and sugar transporters are often specifically or abundantly expressed in these apoplasmic interfaces to provide carbon nutrients and sugar signals to developing pollens, endosperm and embryo. Emerging evidence shows that some of those genes were indeed targeted for selection during crop domestication. In this Opinion paper, I discuss the functional significance of the localized expression of CWINs and sugar transporters in reproductive organs followed by an analysis on how their spatial patterning may be regulated at the molecular levels and how the localized CWIN activity may be exploited for improvement of reproductive output.

Keywords:  Apoplasm; Cell wall invertase; Flower; Fruit; Pollen; SWEET; Seed; Sugar transporter

DOI:  https://doi.org/10.1016/j.jplph.2021.153572
Reprod Fertil Dev. 2021 Nov 30.

Alterations in epididymal sperm maturation caused by ageing.

B P López-Trinidad, R M Vigueras-Villaseñor, M Konigsberg, A Ávalos-Rodríguez, A Rodríguez-Tobón, E Cortés-Barberena, M Arteaga-Silva, E Arenas-Ríos.

The epididymis is an organ that performs all the biochemical changes responsible for sperm maturation. During ageing, histological alterations in the epididymis and decreased protein synthesis have been found. This might affect the sperm maturation process. The aim of this study was to determine if the changes in the epididymis during ageing might cause alterations in sperm maturation. Wistar rats of 3-4months old (young) and 18-21months old (old) were used. The testosterone concentration was determined and the epididymides were dissected and divided in three regions: caput, corpus, and cauda. The tissues were used for histological processing and sperm extraction. Testosterone concentration decreased 34% in the old animals compared to the young ones. The distribution of mannose, sialic acid, and N-acetylglucosamine in the glycocalyx of the sperm membrane of old animals was different from that of young animals. The same occurred with phosphatidylserine externalisation and protein phosphorylation at tyrosine residues. Epididymis histology in old animals showed tubular and cellular degeneration. Our results suggest that ageing affects maturational markers, likely due to alterations in the epididymis as a result of the testosterone decrease associated with ageing.

DOI: https://doi.org/10.1071/RD21081