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Malathion (MAL) is a common organophosphorus pesticide and affects both animal and human reproduction. However, the mechanisms regarding how MAL affects the mammalian oocyte quality and how to prevent it have not been fully investigated. In this study, we used porcine oocyte as a model and proved that MAL impaired porcine oocyte quality in a dose‐dependent manner during maturation. MAL decreased the first polar body extrusion, disrupted spindle assembly and chromosome alignment, impaired cortical granules (CGs) distribution, and increased reactive oxygen species (ROS) level in oocytes. RNA‐seq analysis showed that MAL exposure altered the expression of 2,917 genes in the porcine maturated oocytes and most genes were related to ROS, the lipid droplet process, and the energy supplement. Nevertheless, these defects could be remarkably ameliorated by adding melatonin (MLT) into the oocyte maturation medium. MLT increased oocyte maturation rate and decreased the abnormities of spindle assembly, CGs distribution and ROS accumulation in MAL‐exposed porcine oocytes. More important, MLT upregulated the expression of genes related to lipid droplet metabolism (PPARγ and PLIN2), decreased lipid droplet size and lipid peroxidation in MAL‐exposed porcine oocytes. Finally, we found that MLT increased the blastocysts formation and the cell numbers of blastocysts in MAL‐exposed porcine oocytes after parthenogenetic activation, which was mediated by reduction of ROS levels and maintaining lipid droplet metabolism. Taken together, our results revealed that MLT had a protective action against MAL‐induced deterioration of porcine oocyte quality. [ABSTRACT FROM AUTHOR]

Fluorene‐9‐bisphenol (BHPF), a substitute of bisphenol A (BPA) used in the production of the so‐called "BPA‐free" plastics, has now been shown to be released from commercial plastic bottles into drinking water and has strong anti‐estrogenic activity in mice, which suggests that BHPF is also an environmental toxin. However, whether BHPF exposure has effects on mouse oocyte development is unknown. In this study, the influence of acute exposure to BHPF (50–150 μM, 12 hr) on mouse oocyte maturation and its possible mechanisms were investigated. Of note, 50‐μM BHPF had no effects on the maturation of mouse oocytes, whereas 100‐ and 150‐μM BHPF significantly blocked germinal vesicle breakdown and led to the failure of first polar body extrusion. Particularly, 100‐μM BHPF exposure severely decreased the cellular adenosine triphosphate in a time‐dependent manner, which finally brought out the loss of spindles. In addition, the actin cytoskeleton was also impaired. The defective mitochondrial dynamics and decreased mitochondrial DNA implied the damage of mitochondria in BHPF‐treated oocytes. Increased PINK1, Beclin1, and LC3B protein level and decreased TOMM20 and TOMM17A protein level illustrated that mitophagy was induced, which also confirmed that BHPF exposure impaired the cellular mitochondria. Moreover, BHPF induced reactive oxygen species accumulation and early apoptosis. Oocyte quality was also impaired by BHPF exposure through altering histone modifications evidenced by increased H3K9me3 and H3K27me3 levels. Collectively, our results indicated that BHPF exposure disrupted mouse oocyte maturation and reduced oocyte quality through affecting cytoskeleton architecture, mitochondrial function, oxidative stress, apoptosis, and histone modifications. Environ. Mol. Mutagen. 60:243–253, 2019. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

SURVIVIN is an essential chromosomal passenger complex (CPC) subunit and participates in cell division. In this study, we used porcine oocyte as a model to investigate the roles of Survivin during porcine oocyte maturation. Survivin was highly expressed in germinal vesicle (GV) and germinal vesicle breakdown (GVBD) stages oocytes, mainly localized in the GV at GV stage and on the chromosomes after GVBD. We have used RNA interference to specifically deplete Survivin in oocytes during in vitro maturation (IVM). Immunofluorescence assay showed that Survivin-depleted oocytes failed to produce polar body in meiosisⅠ (failed to complete cytokinesis), and they were arrested in metaphaseⅠwith misaligned chromosomes. The homologous chromosomes in Survivin-depleted oocytes could not be separated normally. Moreover, both the phosphorylation levels of Aurora B and the mRNA level of Mad2L1 related to spindle assembly checkpoint (SAC) was decreased in Survivin-depleted oocytes, which thus inhibited the degradation of Cyclin B1 (CCNB1) to complete meiosis. Taken together, we conclude that Survivin is an important mediator of centromere and midbody docking of Aurora-B as well as its activity and regulates SAC and MPF activity during meiosis in porcine oocytes. [ABSTRACT FROM AUTHOR]

Sodium fluoride (NaF) is used as a medicine to prevent tooth decay; however, excessive NaF could cause a pathological damage to the health. Recent studies showed that NaF impaired mouse oocyte maturation, included of abnormal spindle configuration, actin cap formation, cortical granule‐free domain formation, and the following development after fertilization. However, few studies used large animals as models to study the toxicology of NaF on oocytes maturation. We proposed a hypothesis that NaF would affect the nuclear and cytoplasmic maturation of porcine oocytes and DNA methylation pattern of imprinted genes in oocytes. Our results showed that NaF affected cumulus expansion, polar body emission, spindle morphology, cortical granule distribution, early apoptosis, and the following development after parthenogenetic activation during porcine oocyte maturation. Moreover, NaF increased the DNA methylation of NNAT and decreased its expression, which disturbed the glucose transport in oocytes. These results suggest that NaF impairs the porcine oocytes maturation epigenetically, which provides a new toxicological mechanism of NaF on the oocyte maturation. Environ. Mol. Mutagen. 59:223–233, 2018. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Checkpoint 1 (Chk1), as an important member of DNA replication checkpoint and DNA damage response, has an important role during the G2/M stage of mitosis. In this study, we used porcine oocyte as a model to investigate the function ofChk1during porcine oocyte maturation.Chk1was expressed from germinal vesicle (GV) to metaphase II (MII) stages, mainly localized in the cytoplasm at GV stage and moved to the spindle after germinal vesicle breakdown (GVBD).Chk1depletion not only induced oocytes to be arrested at MI stage with abnormal chromosomes arrangement, but also inhibited the degradation of Cyclin B1 and decreased the expression of Mitotic Arrest Deficient 2-Like 1 (Mad2L1), one of spindle assembly checkpoint (SAC) proteins, and cadherin 1 (Cdh1), one of coactivation for anaphase-promoting complex/cyclosome (APC/C). Moreover,Chk1overexpression delayed GVBD. These results demonstrated thatChk1facilitated the timely degradation of Cyclin B1 at anaphase I (AI) and maintained the expression of Mad2L1 and Cdh1, which ensured that all chromosomes were accurately located in a line, and then oocytes passed metaphase I (MI) and AI and exited from the first meiotic division successfully. In addition, we proved that Chk1 had not function on GVBD of porcine oocytes, which suggested that maturation of porcine oocytes did not need the DNA damage checkpoint, which was different from the mouse oocyte maturation. [ABSTRACT FROM PUBLISHER]

Initiation of mouse embryonic development depends upon a series of fertilization-induced rises in intracellular Ca2+. Complete egg activation requires influx of extracellular Ca2+; however, the channels that mediate this influx remain unknown. Here, we tested whether the α1 subunit of the T-type channel CaV3.2, encoded by Cacna1h, mediates Ca2+ entry into oocytes. We show that mouse eggs express a robust voltage-activated Ca2+ current that is completely absent in Cacna1h-/- eggs. Cacna1h-/- females have reduced litter sizes, and careful analysis of Ca2+ oscillation patterns in Cacna1h-/- eggs following in vitro fertilization (IVF) revealed reductions in first transient length and oscillation persistence. Total and endoplasmic reticulum (ER) Ca2+ stores were also reduced in Cacna1h-/- eggs. Pharmacological inhibition of CaV3.2 in wild-type CF-1 strain eggs using mibefradil or pimozide reduced Ca2+ store accumulation during oocyte maturation and reduced Ca2+ oscillation persistence, frequency and number following IVF. Overall, these data show that CaV3.2 T-type channels have prev8iously unrecognized roles in supporting the meiotic-maturation-associated increase in ER Ca2+ stores and mediating Ca2+ influx required for the activation of development. [ABSTRACT FROM AUTHOR]

Mammalian preimplantation development culminates in the formation of a blastocyst which undergoes extensive gene expression regulation to successfully implant into the maternal endometrium. Zinc-finger HIT domain-containing (ZNHIT) 1 and 2 are members of a highly conserved family, yet they have been identified as subunits of distinct complexes. Here we report that knockout of either Znhit1 or Znhit2 results in embryonic lethality during peri-implantation stages. Znhit1 and Znhit2 mutant embryos have overlapping phenotypes, including reduced proportion of SOX2-positive ICM cells, a lack of Fgf4 expression and aberrant expression of NANOG and SOX17. Furthermore, we find that the similar phenotypes are caused by distinct mechanisms. Specifically, embryos lacking ZNHIT1 likely fail to incorporate sufficient H2A.Z at the promoter region of Fgf4 and other genes involved in cell projection organization resulting in impaired invasion of trophoblast cells during implantation. In contrast, Znhit2 mutant embryos display a complete lack of nuclear EFTUD2, a key component of U5 spliceosome, indicating a global splicing deficiency. Our findings unveil the indispensable yet distinct roles of ZNHIT1 and ZNHIT2 in early mammalian embryonic development., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The effective proliferation and differentiation of trophoblast stem cells (TSCs) is indispensable for the development of the placenta, which is the key to maintaining normal fetal growth during pregnancy. Kruppel-like factor 5 (Klf5) is implicated in the activation of pluripotency gene expression in embryonic stem cells (ESCs), yet its function in TSCs is poorly understood. Here, we showed that Klf5 knockdown resulted in the downregulation of core TSC-specific genes, consequently causing rapid differentiation of TSCs. Consistently, Klf5-depleted embryos lost the ability to establish TSCs in vitro. At the molecular level, Klf5 preferentially occupied the proximal promoter regions and maintained an open chromatin architecture of key TSC-specific genes. Deprivation of Klf5 impaired the enrichment of p300, a major histone acetyl transferase of H3 lysine 27 acetylation (H3K27ac), and further reduced the occupancy of H3K27ac at promoter regions, leading to decreased transcriptional activity of TSC pluripotency genes. Thus, our findings highlight a novel mechanism of Klf5 in regulating the self-renewal and differentiation of TSCs and provide a reference for understanding placental development and improving pregnancy rates., (© The Author(s) (2023). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, CEMCS, CAS.)

Objective: To investigate the relationship between di-(2-ethyl hexyl) phthalate (DEHP) and male infertility by detecting the concentration of DEHP in the seminal plasma of the patient with idiopathic asthenozoospermia (IAS)., Methods: This study included 45 infertile males with diagnosed IAS in the observation group and another 45 men with normal sperm parameters as controls. We obtained the general baseline data on the subjects, determined the concentration of DEHP in the seminal plasma, the ROS level and the sperm DNA fragmentation index (DFI), and compared them between the two groups of males., Results: There were no statistically significant differences between the two groups of subjects in age, living habits and other general in baseline data (P > 0.05). The IAS patients, in comparison with the normal controls, showed significantly increased DEHP concentration in the seminal plasma (［0.45 ± 0.09］ vs ［0.23 ± 0.05］ μg/ml, P < 0.05), ROS level (［569.4 ± 45.3］ vs ［317.6 ± 27.8］ pmol/106 sperm, P < 0.05) and sperm DFI (［22.1 ± 8.3］% vs ［10.5 ± 6.7］%, P < 0.05). The concentration of DEHP in the seminal plasma was correlated positively with the ROS level (r = 0.77, P < 0.05) and sperm DFI (r = 0.75, P < 0.05) but negatively with the percentage of progressively motile sperm (r = －0.81, P < 0.05)., Conclusions: The DEHP level is escalated in the seminal plasma of the IAS patient, which may be responsible for the reduced sperm motility and increased DFI of the patient.

Stem cells have the potential to differentiate into specialized cell types under specific conditions in vivo or in vitro, which are used to cure many diseases related to aging. Somatic cell nuclear transfer (SCNT) can reprogram differential somatic cells into cloned embryos and embryonic stem cells can be derived from these cloned embryos. Recipient oocytes have healthier mitochondria and can improve the metabolism competence, lessen the ROS damage, and rejuvenate mitochondrial function of aged cells during reprogramming. Here, we describe a protocol to isolate aged somatic cells and reprogram them into embryonic stem cells by SCNT. These stem cells can be used to differentiate into regenerative somatic cells and replace the aged cells.