Molecular Reproduction and Development最新文献

The vascular endothelial growth factor-A (VEGFA) system is a complex set of proteins, with multiple isoforms and receptors, including both angiogenic (VEGFxxx, VEGFR2) and antiangiogenic members (VEGFxxxb, VEGFR1 and soluble forms of VEGFR). The members of the VEGF system affect the proliferation, survival, and migration of endothelial and nonendothelial cells and are involved in the regulation of follicular angiogenesis and development. The production of VEGF by secondary follicles stimulates preantral follicular development by directly affecting follicular cells and promoting the acquisition of the follicular vasculature and downstream antrum formation. Additionally, the pattern of expression of the components of the VEGF system may provide a proangiogenic milieu capable of triggering angiogenesis and stimulating follicular cells to promote antral follicle growth, whereas, during atresia, this milieu becomes antiangiogenic and blocks follicular development.

Rapamycin induces autophagosome formation and activity during oocyte maturation, improved fertilization ability of matured oocytes, and early embryonic developmental competence. However, potential changes in mitochondrial fission and mitophagy via regulation of autophagy in early porcine embryonic development have not been previously studied. Here, we investigated embryonic developmental ability and quality of porcine embryos 2 days after in vitro fertilization and following treatment with 1 and 10 nM rapamycin. As a results, 1 nM rapamycin exposure significantly improved (p < 0.05) blastocyst developmental competence compared to that in nontreated embryos (nontreated: 26.2 ± 5.7% vs. 1 nM rapamycin: 35.3 ± 5.1%). We observed autophagic (LC3B) and mitochondrial fission protein expression (dynamin-related protein-1 [DRP1] and pDRP1-Ser616) at the cleavage stage of 1 and 10 nM rapamycin-treated porcine embryos, using Western blot and immunofluorescence analyses. Interestingly, 1 nM rapamycin treatment significantly improved autophagy formation, mitochondrial activation, and mitochondrial fission protein levels (p < 0.05; p-DRP1 [Ser616]) at the cleavage stage of porcine embryos. Additionally, mitophagy was significantly increased in blastocysts treated with 1 nM rapamycin. In conclusion, our results suggest that rapamycin promotes blastocyst development ability in porcine embryos through mitochondrial fission, activation, and mitophagy in in vitro culture.

Thyroid autoimmunity (TAI) triggered by genetic and epigenetic variation occurs mostly in women of reproductive age. TAI is described mainly by positivity of anti-thyroid peroxidase antibody (TPO-Ab) and/or thyroglobulin antibody (TG-Ab). TPO-Ab, but not TG-Ab, was suggested to be associated with pregnancy outcome in euthyroid women undergoing assisted reproductive technology (ART), but their results are conflicting. This meta-analysis was performed to decide whether the presence of TPO-Ab—in a concentration dependent manner—correlates with the success of ART. A systematic literature search was performed in the PubMed, Web of Science, and EMBASE databases for relevant articles published from January 1999 to April 2022, and these studies focused on the effect of TAI on pregnancy outcomes of women who underwent in vitro fertilization, intracytoplasmic sperm injection and intrauterine insemination and met the inclusion criteria: (i) the studies were prospective or retrospective study; (ii) all patients undergoing ART were tested for thyroid-related antibodies; (iii) the assessed ART outcomes included miscarriage rate (MR) or delivery rate (DR). The exclusion criteria were: (i) female congenital uterine malformation, chromosomal diseases and other infectious diseases; (ii) overt hypothyroidism or pre-existing thyroid disease; (iii) thrombus tendency. We divided the included patients into three groups according to the TPO-Ab threshold they defined: (i) TPO-Ab (−), threshold <34 IU/mL; (ii) TPO-Ab-34, threshold >34 IU/mL; (iii) TPO-Ab-100, threshold >100 IU/mL. We then extracted necessary relevant data, including MR and DR. Egger's test was used to evaluate the risk of publication bias. This meta-analysis included a total of 7 literatures involving 7466 patients with TAI (−) and 965 patients with TAI (+) and revealed that there was no significant difference between group TPO-Ab-34 and group TPO-Ab (−) in MR [risk ratio (RR): 0.61 (0.35, 1.08), p = 0.09] and DR [RR: 0.97 (0.83, 1.13), p = 0.69]. By contrast, compared to TPO-Ab (−) group, TPO-Ab-100 patients showed markedly higher MR [RR: 2.12 (1.52, 2.96), p = 0.0046], and lower DR [RR: 0.66 (0.49, 0.88), p < 0.0001] with high degree of statistical significance. This meta-analysis suggests that, for euthyroid patients, high level of TPO-Ab (>100 IU/mL) could adversely influence the pregnancy outcome of ART.

Intrauterine growth restriction (IUGR) is a severe complication in swine production. Placental insufficiency is responsible for inadequate fetal growth, but the specific etiology of placental dysfunction-induced IUGR in pigs remains poorly understood. In this work, placenta samples supplying the lightest weight (LW) and mean weight (MW) pig fetuses in the litter at Day 65 (D65) of gestation were collected, and the relationship between fetal growth and placental morphologies and functions was investigated using histomorphological analysis, RNA sequencing, quantitative polymerase chain reaction, and in vitro experiment in LW and MW placentas. Results showed that the folded structure of the epithelial bilayer of LW placentas followed a poor and incomplete development compared with that of MW placentas. A total of 654 differentially expressed genes (DEGs) were screened out between the LW and MW placentas, and the gene encodes receptor for activated C kinase 1 (RACK1) was found to be downregulated in LW placentas. The DEGs were mainly enriched in translation, ribosome, protein synthesis, and mammalian target of rapamycin (mTOR) signaling pathway according to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. In vitro experiments indicated that the decreased RACK1 in LW placentas may be involved in abnormal development of placental folds (PFs) by inhibiting the proliferation and migration of porcine trophoblast cells. Taken together, these results revealed that RACK1 may be a vital regulator in the development of PFs via regulating trophoblast cell proliferation and migration in pigs.

Luteal dysfunctions lead to fertility disorders and pregnancy complications. Normal luteal function is regulated by many factors, including luteinizing hormone (LH). The luteotropic roles of LH have been widely investigated but its role in the process of luteolysis has received little attention. LH has been shown to have luteolytic effects during pregnancy in rats and the role of intraluteal prostaglandins (PGs) in LH-mediated luteolysis has been demonstrated by others. However, the status of PG signaling in the uterus during LH-mediated luteolysis remains unexplored. In this study, we utilized the repeated LH administration (4×LH) model for luteolysis induction. We have examined the effect of LH-mediated luteolysis on the expression of genes involved in luteal/uterine PG synthesis, luteal PGF_2α signaling, and uterine activation during different stages (mid and late) of pregnancy. Further, we analyzed the effect of overall PG synthesis machinery blockage on LH-mediated luteolysis during late pregnancy. Unlike the midstage of pregnancy, the expression of genes involved in PG synthesis, PGF_2α signaling, and uterine activation in late-stage pregnant rats' luteal and uterine tissue increase 4×LH. Since the cAMP/PKA pathway mediates LH-mediated luteolysis, we analyzed the effect of inhibition of endogenous PG synthesis on the cAMP/PKA/CREB pathway, followed by the analysis of the expression of markers of luteolysis. Inhibition of endogenous PG synthesis did not affect the cAMP/PKA/CREB pathway. However, in the absence of endogenous PGs, luteolysis could not be activated to the full extent. Our results suggest that endogenous PGs may contribute to LH-mediated luteolysis, but this dependency on endogenous PGs is pregnancy-stage dependent. These findings advance our understanding of the molecular pathways that regulate luteolysis.

Perturbations of estrogen signaling during developmental stages of high plasticity may lead to adverse effects later in life. Endocrine-disrupting chemicals (EDC) are compounds that interfere with the endocrine system by particularly mimicking the action of endogenous estrogens as functional agonists or antagonists. EDCs compose synthetic and naturally occurring compounds discharged into the environment, which may be taken up via skin contact, inhalation, orally due to contaminated food or water, or via the placenta during in utero development. Although estrogens are efficiently metabolized by the liver, the role of circulating glucuro- and/or sulpho-conjugated estrogen metabolites in the body has not been fully addressed to date. Particularly, the role of intracellular cleavage to free functional estrogens could explain the hitherto unknown mode of action of adverse effects of EDC at very low concentrations currently considered safe. We summarize and discuss findings on estrogenic EDC with a focus on early embryonic development to highlight the need for reconsidering low dose effects of EDC.

Somatic cell nuclear transfer (SCNT) is commercially used despite incomplete nuclear reprogramming of the somatic cell nucleus by the enucleated oocyte compromising its efficiency. Oocyte selection is a key factor in increasing this efficiency as its cytoplasm reprograms the differentiated cell. In this study, we adapted a methodology to characterize epialleles in potential epigenetic markers in single in vitro matured oocytes. Characterization of the regions that control the expression of imprinted genes, X-chromosome inactivation, and satellite I DNA (IGF2, ICR-H19, XIST, RepA, and SAT1) showed methylated and unmethylated alleles in the imprinted genes IGF2 and ICR-H19 while XIST-DMR1 and RepA showed hypermethylated alleles. There was great variation in methylation patterns for candidate regions which may be related to oocyte quality. Moreover, the identification of different epialleles in the same oocyte suggests that, at least for those loci, the epigenome of the metaphase plate and polar body is different. The single-cell bisulfite polymerase chain reaction technique can be used to improve the precision of selecting the best oocytes for SCNT procedures, thereby increasing its efficiency.

The biology of preimplantation embryo gene expression began 56 years ago with studies of the effects of protein synthesis inhibition and discovery of changes in embryo metabolism and related enzyme activities. The field accelerated rapidly with the emergence of embryo culture systems and progressively evolving methodologies that have allowed early questions to be re-addressed in new ways and in greater detail, leading to deeper understanding and progressively more targeted studies to discover ever more fine details. The advent of technologies for assisted reproduction, preimplantation genetic testing, stem cell manipulations, artificial gametes, and genetic manipulation, particularly in experimental animal models and livestock species, has further elevated the desire to understand preimplantation development in greater detail. The questions that drove enquiry from the earliest years of the field remain drivers of enquiry today. Our understanding of the crucial roles of oocyte-expressed RNA and proteins in early embryos, temporal patterns of embryonic gene expression, and mechanisms controlling embryonic gene expression has increased exponentially over the past five and a half decades as new analytical methods emerged. This review combines early and recent discoveries on gene regulation and expression in mature oocytes and preimplantation stage embryos to provide a comprehensive understanding of preimplantation embryo biology and to anticipate exciting future advances that will build upon and extend what has been discovered so far.