Expression, modification, and activity of microRNAs are dynamically regulated in early mouse embryos unveiled by sensitive sequencing.

Cadmium is a major environmental toxicant that is released into the atmosphere, water and soil in the form of cadmium oxide, cadmium chloride, or cadmium sulfide via industrial activities, such as the manufacturing of batteries and pigments, metal smelting and refining and municipal waste incineration. In the present study, we investigated the effects of cadmium exposure on sperm quality parameters, fertilization capacity and early embryonic development. Our study showed that in vitro incubation of human or mouse sperms with cadmium for a long time (up to 24 hours) could significantly decreased sperm motility in a concentration- and time-dependent manner. Exposure to cadmium in the environment for a short term (30 min) did not affect sperm motility but significantly reduced in vitro fertilization rate. We also evaluated the effects of cadmium at concentrations of 0.625 μg/ml, and 1.25 μg/ml on early embryonic development in vitro and observed that the blastocyst formation rate dramatically decreased with increasing cadmium concentration. This finding emphasizes the hazardous effects of cadmium on sperm quality as well as on natural embryo development and raises greater concerns regarding cadmium pollution.

Acetamiprid (ACE) and imidacloprid (IMI) are two major members in the family of neonicotinoid pesticides, which are synthesized with a higher selectivity to insects. The present study determined and compared in vitro effects of ACE, IMI and nicotine on mammalian reproduction by using an integrated testing strategy for reproductive toxicology, which covered sperm quality, sperm penetration into oocytes and preimplantation embryonic development. Direct chemical exposure (500 µM or 5 mM) on spermatozoa during capacitation was performed, and in vitro fertilization (IVF) process, zygotes and 2-cell embryos were respectively incubated with chemical-supplemented medium until blastocyst formation to evaluate the reproductive toxicity of these chemicals and monitor the stages mainly affected. Generally, treatment of 500 µM or 5 mM chemicals for 30 min did not change sperm motility and DNA integrity significantly but the fertilization ability in in vitro fertilization (IVF) process, indicating that IVF process could detect and distinguish subtle effect of spermatozoa exposed to different chemicals. Culture experiment in the presence of chemicals in medium showed that fertilization process and zygotes are adversely affected by direct exposure of chemicals (PIMI>ACE, whereas developmental progression of 2-cell stage embryos was similar to controls (P>0.05). These findings unveiled the hazardous effects of neonicotinoid pesticides exposure on mammalian sperm fertilization ability as well as embryonic development, raising the concerns that neonicotinoid pesticides may pose reproductive risks on human reproductive health, especially in professional populations.

Implantation failure is not only a major cause of early pregnancy loss, but it is also an obstacle to assisted reproductive technologies. The identification of potential circulating biomarkers for recurrent miscarriage (RM) and/or recurrent implantation failure would contribute to the development of novel diagnosis and prediction techniques. MiR (miR-23a-3p, 27a-3p, 29a-3p, 100-5p, 127-3p and 486-5p) expression in the villi, decidual tissues and peripheral blood plasma and serum were validated by qPCR, and the localization of miRs in the villi and decidual tissues of RM and normal pregnancy (NP) women were detected by in situ hybridization. The invasiveness of HTR8/SVneo cells was determined using a Transwell assay. The predictive values of miRs for RM and the outcome of IVF-ET were respectively calculated by the receiver operating characteristic analysis. The signals of six miRs were observed in the villi and decidual tissues of RM and NP women. The villus miR-27a-3p, miR-29a-3p and miR-100-5p were significantly up-regulated, whereas miR-127-3p and miR-486-5p appeared to be down-regulated in RM women compared to NP women. The invasiveness of HTR8/SVneo cells transfected with miR-23a-3p mimics was evidently weakened, whereas that of cells transfected with miR-127-3p mimics was obviously enhanced. The peripheral blood plasma levels of miR-27a-3p, miR-29a-3p, miR-100-5p and miR-127-3p were significantly increased, whereas that of miR-486-5p was remarkably decreased in RM compared to NP women. By contrast, serum miR-23a-3p and miR-127-3p were significantly decreased, whereas that of miR-486-5p was remarkably increased. The combination of six plasma miRs levels discriminated RM with a sensitivity of 100% and a specificity of 83.3%, whereas that of six serum miRs levels showed a sensitivity of 78.3% and a specificity of 93.1%. In the IVF-ET cohort, the significantly decreased peripheral blood plasma levels of miR-23a-3p, miR-27a-3p, miR-100-5p and miR-127-3p, and the serum levels of miR-100-5p and miR-486-5p, in addition to the significantly increased serum level of miR-27a-3p, were found to be associated with the failure of ET. Moreover, the combination of plasma miR-23a-3p, miR-27a-3p, miR-29a-3p, miR-100-5p, miR-127-3p and miR-486-5p levels discriminated the outcome of IVF-ET with a sensitivity of 68.1% and a specificity of 54.1%, whereas the combination of plasma miR-127-3p and miR-486-5p levels showed a sensitivity of 50.0% and a specificity of 75.3%. Circulating miR-23a-3p, miR-27a-3p, miR-29a-3p, miR-100-5p, miR-127-3p and miR-486-5 might be involved in RM pathogenesis and present potential diagnostic biomarkers for RM. Meanwhile, these miRs, in particular miR-127-3p and miR-486-5p, provide promising prediction indexes for the outcomes of IVF-ET.

To reveal the relationship between mitochondrial function in cumulus cells (CCs) and the aging-related decline in ovarian function and reproductive capacity. Retrospective and transcriptome analysis of human tissue. University hospital. A total of 186 infertile women with normal weight and no other diseases, including 86 young women (aged <38 years) with normal ovarian reserve and 100 advanced-age women (aged ≥38 years) with diminished ovarian reserve. None. Embryo development data were analyzed. The mitochondrial ultrastructure of CCs was observed by transmission electron microscopy. Mitochondrial activity was detected by immunofluorescence. The per-CC mitochondrial deoxyribonucleic acid copy numbers and cellular adenosine triphosphate levels were quantified. Unbiased comprehensive genome-wide transcriptomics was performed. The functions of all annotated genes and biologic pathways were analyzed by the Kyoto Encyclopedia of Genes and Genomes. Advanced-age women with diminished ovarian function had significantly fewer retrieved oocytes and lower embryo quality. The normal mitochondrial rate in CCs was significantly lower. In addition to mitochondrial morphology and structural changes, the fluorescence intensity of Fluo-3/AM was significantly higher, and that of MitoTracker was lower than that of young women with normal ovarian reserve, suggesting that age negatively affects the mitochondrial activity of CCs. The per-CC mitochondrial deoxyribonucleic acid copy number and adenosine triphosphate levels significantly decreased in the advanced-age group. The Kyoto Encyclopedia of Genes and Genomes analysis showed that differentially expressed genes were significantly enriched in the oxidative phosphorylation pathway. Additionally, most mitochondrially encoded genes related to oxidative phosphorylation were significantly down-regulated in the advanced-age group. We present current evidence that mitochondrial dysfunction in CCs may play a key role in the age-related decline in ovarian function and reproductive capacity.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age, and oocyte developmental competence is altered in patients with PCOS. In recent years microRNAs (miRNAs) have emerged as important regulators of gene expression, the aim of the study was to study miRNAs expression patterns of cumulus cells from PCOS patients. The study included 20 patients undergoing in vitro fertilization (IVF) and intra-cytoplasmic sperm injection (ICSI): 10 diagnosed with PCOS and 10 matching controls. We used deep sequencing technology to identify the miRNAs differentially expressed in the cumulus cells of PCOS. There were 17 differentially expressed miRNAs in PCOS cumulus cells, including 10 miRNAs increase and 7 miRNAs decrease. These miRNAs were predicted to target a large set of genes with different functions, including Wnt- and MAPK- signaling pathways, oocyte meiosis, progesterone-mediated oocyte maturation and cell cycle. Unsupervised hierarchical clustering analysis demonstrated that there was a specific miRNAs expression pattern in PCOS cumulus cells. We found that the miRNAs expression profile was different in cumulus cells isolated from PCOS patients compared with control. This study provided new evidence for understanding the pathogenesis of PCOS.