The Role of N6-methyladenosine Modification in Gametogenesis and Embryogenesis: Impact on Fertility.

The most common epigenetic modification of messenger ribonucleic acids (mRNAs) is N6-methyladenosine (m6A), which is mainly located near the 3' untranslated region of mRNAs, near the stop codons, and within internal exons. The biological effect of m6A is dynamically modified by methyltransferases (writers), demethylases (erasers), and m6A-binding proteins (readers). By controlling post-transcriptional gene expression, m6A has a significant impact on numerous biological functions, including RNA transcription, translation, splicing, transport, and degradation. Hence, m6A influences various physiological and pathological processes, such as spermatogenesis, oogenesis, embryogenesis, placental function, and human reproductive system diseases. During gametogenesis and embryogenesis, genetic material undergoes significant changes, including epigenomic modifications such as m6A. From spermatogenesis and oogenesis to the formation of an oosperm and early embryogenesis, m6A changes occur at every step. m6A abnormalities can lead to gamete abnormalities, developmental delays, impaired fertilization, and maternal-to-zygotic transition blockage. Both mice and humans with abnormal m6A modifications exhibit impaired fertility. In this review, we discuss the dynamic biological effects of m6A and its regulators on gamete and embryonic development and review the possible mechanisms of infertility caused by m6A changes. We also discuss the drugs currently used to manipulate m6A and provide prospects for the prevention and treatment of infertility at the epigenetic level.

Triphenyltin chloride exposure inhibits meiotic maturation of mouse oocytes by disrupting cytoskeleton assembly and cell cycle progression.

Triphenyltin chloride (TPTCL) is widely used in various industrial and agricultural applications. This study aimed to elucidate the mechanisms underlying the toxicological effects of TPTCL on oocytes. The obtained findings revealed that TPTCL exposure reduced polar body extrusion (PBE) and induced meiotic arrest. Mechanistically, TPTCL disrupted meiotic spindle assembly and chromosome alignment. Further analysis indicated a significant decrease in p-MAPK expression, and disturbances in the localization of Pericentrin and p-Aurora A in TPTCL exposed oocytes, which suggesting impaired microtubule organizing center (MTOC)function. Moreover, TPTCL exposure enhance microtubule acetylation and microtubule instability. Therefore, the spindle assembly checkpoint (SAC) remained activated, and the activity of the anaphase-promoting complex (APC) was inhibited, thereby preventing oocytes from progressing into the entering anaphase I (AI) stage. TPTCL exposure also augmented the actin filaments in the cytoplasm. Notably, mitochondrial function appeared unaffected by TPTCL, as evidenced indicated by stable mitochondrial membrane potential and ATP content. Furthermore, TPTCL treatment altered H3K27me2, H3K27me3 and H3K9me3 levels, suggesting changes in epigenetic modifications in oocytes. Taken together, our results suggest that TPTCL disrupts cytoskeleton assembly, continuously activates SAC, inhibits APC activity, and blocks meiotic progression, ultimately impair oocyte maturation.

Bisphenol Z exposure inhibits oocyte meiotic maturation by rupturing mitochondrial function.

The use of bisphenol A (BPA) has been restricted due to its endocrine-disrupting effects. As a widely used alternative to BPA today, environmental levels of bisphenol Z (BPZ) continue to rise and accumulate in humans. Oocyte quality is critical for a successful pregnancy. Nevertheless, the toxic impacts of BPZ on the maturation of mammalian oocytes remain unexplored. Therefore, the impacts of BPZ and BPA on oocyte meiotic maturation were compared in an in vitro mouse oocyte culture model. Exposure to 150 µM of both BPZ and BPA disrupted the assembly of the meiotic spindle and the alignment of chromosomes, and BPZ exerted stronger toxicological effects than BPA. Furthermore, BPZ resulted in aberrant expression of F-actin, preventing the formation of the actin cap. Mechanistically, BPZ exposure disrupted the mitochondrial localization pattern, reduced mitochondrial membrane potential and ATP content, leading to impaired mitochondrial function. Further studies revealed that BPZ exposure resulted in oxidative stress and altered expression of genes associated with anti-oxidative stress. Moreover, BPZ induced severe DNA damage and triggered early apoptosis in oocytes, accompanied by impaired lysosomal function. Overall, the data in this study suggest that BPZ is not a safe alternative to BPA. BPZ can trigger early apoptosis by affecting mitochondrial function and causing oxidative stress and DNA damage in oocytes. These processes disrupt cytoskeletal assembly, arrest the cell cycle, and ultimately inhibit oocyte meiotic maturation.

Carbendazim exposure inhibits mouse oocytes meiotic maturation in vitro by destroying spindle assembly.

Successful fertilization and early embryonic development heavily depend on the quality of the oocytes. Carbendazim (CBZ), a broad-spectrum fungicide, is widely available in the environment and has adverse effects on organisms. The present study focused on exploring the potential reproductive toxicity of CBZ exposure by investigating its effects on the maturation of mouse oocytes. The results demonstrated that although no disruptions were observed in the G2/M stage transition for meiosis resumption, CBZ did hinder the polar body extrusion (PBE) occurring during oocyte maturation. Cell cycle distribution analysis revealed that CBZ exposure interfered with the meiotic process, causing oocytes to be arrested at the metaphase I (MI) stage. The subsequent investigation highlighted that CBZ exposure impeded the spindle assembly and chromosomal alignment, which was linked to a decline in the level of p-MAPK. Additionally, CBZ exposure adversely affected the kinetochore-microtubule (K-MT) attachment, leading to the persistent activation of the spindle-assembly checkpoint (SAC). The study further noticed a substantial rise in the acetylation of α-tubulin and a reduction in spindle microtubule stability in CBZ-treated oocytes. In addition, the distribution pattern of estrogen receptor alpha (ERα) was altered in oocytes treated with CBZ, with abnormal aggregation on the spindles. CBZ exposure also resulted in altered histone modifications. A notable finding from this research was that the meiotic maturation of some oocytes remained unaffected even after CBZ treatment. However, during the ensuing metaphase II (MII) stage, these oocytes displayed anomalies in their spindle morphology and chromosome arrangement and diminished ability to bind to the sperm. The observations made in this study underscore the potential for CBZ to disrupt the meiotic maturation of oocytes, leading to a decline in the overall quality of oocytes.

High-sensitivity acoustic impedance sensing based on forward Brillouin scattering in a highly nonlinear fiber.

By using radial acoustic modes induced forward Brillouin scattering (FBS) in a highly nonlinear fiber (HNLF), to the best of our knowledge we have demonstrated acoustic impedance sensing with the sensitivity reaching beyond 3MHz for the first time. Benefiting from the high acousto-optical coupling efficiency, both radial acoustic modes (R0,m) and torsional-radial acoustic modes (TR2,m) induced FBS in HNLF have larger gain coefficient and scattering efficiency than those in standard single-mode fiber (SSMF). This provides better signal-to-noise ratio (SNR) and hence larger measurement sensitivity. By using R0,20 mode in HNLF, we have achieved a higher sensitivity of 3.83 MHz/[kg/(s · mm2)], in contrast to that of 2.70 MHz/[kg/(s · mm2)] when measured using R0,9 mode (with almost the largest gain coefficient) in SSMF. Meanwhile, with the use of the TR2,5 mode in HNLF, the sensitivity is measured to be 0.24 MHz/[kg/(s · mm2)], which is still 1.5 times larger than that reported when using the same mode in SSMF. The improved sensitivity would make the detection of the external environment by FBS based sensors more accurate.

Recent Insights into Noncoding RNAs in Primary Ovarian Insufficiency: Focus on Mechanisms and Treatments.

CONTEXT: Primary ovarian insufficiency (POI) is a heterogeneous disease with an unknown underlying trigger or root cause. Recently many studies evaluated noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNA (lncRNAs), circular RNAs (circRNAs), and small interfering RNAs (siRNAs) for their associations with POI. EVIDENCE ACQUISITION: In this review, we outline the biogenesis of various ncRNAs relevant to POI and summarize the evidence for their roles in the regulation of disease occurrence and progression. Articles from 2003 to 2022 were selected for relevance, validity, and quality from results obtained in PubMed and Google Scholar using the following search terms: noncoding RNAs; primary ovarian insufficiency; premature ovarian failure; noncoding RNAs and primary ovarian insufficiency/premature ovarian failure; miRNAs and primary ovarian insufficiency/premature ovarian failure; lncRNAs and primary ovarian insufficiency/premature ovarian failure; siRNAs and primary ovarian insufficiency/premature ovarian failure; circRNAs and primary ovarian insufficiency/premature ovarian failure; pathophysiology; and potential treatment. All articles were independently screened for eligibility by the authors. EVIDENCE SYNTHESIS: This review summarizes the biological functions and synthesis of miRNAs, lncRNAs, siRNAs, and circRNAs in POI and discusses the findings of clinical and in vitro and in vivo studies. Although there is variability in the findings of individual studies, overall the available literature justifies the conclusion that dysregulated ncRNAs play significant roles in POI. CONCLUSION: The potential of ncRNAs in the treatment of POI requires further investigation, as ncRNAs derived from mesenchymal stem cell-secreted exosomes play pivotal roles and have considerable therapeutic potential in a multitude of diseases.

Study on the logic and effectiveness of crisis learning in the promotion policy adjustment: an observation based on the adjustment of COVID-19 prevention policy in China.

Background: As the impact of COVID-19 on normal production and living conditions diminishes, this serious emergency is come to an end. China's policy framework has facilitated positive adjustment over the past 3 years by timely modifying its emergency response to changes in viruses and epidemics. This paper aims to explore the logic of China's policy framework that promoted policy adjustment through crisis learning during COVID-19. Methods: By gathering and classifying China's epidemic prevention policies throughout the past 3 years, integrating policy texts, and analyzing key events, this article examines the process of supporting policy adjustment through crisis learning in the policy system during COVID-19. Results: The Chinese government's COVID-19 policy adjustment process can be divided into four stages, namely 'The period of stress response', 'The period of COVID-19 prevention and control', 'The period of regular prevention and control', and 'The period of overall adjustment'. The policy adjustments in each stage demonstrate the logic and effectiveness of crisis learning in the promotion policy adjustment. The study has determined that the motivational logic comprises three crucial elements: security requirements, accountability pressure, and reputation management. The institutional logic encompasses both the organizational and resourceful environments, and the institutional and cultural environment. Additionally, the behavioral logic of policy adaptation aligns with the strategy of crisis learning. Meanwhile, the logical framework of 'crisis learning-policy adjustment' can be verified using the Chinese government's policy adjustment in COVID-19 as an example. Conclusion: Establishing an effective post-crisis learning system is crucial to improving the effectiveness of crisis response. There is a logical link between crisis learning and policy adjustment. The implementation of policy adjustment needs to be based on the results of crisis learning. Government departments are essential for crisis learning and policy adjustment.

Role of EGFR expressed on the granulosa cells in the pathogenesis of polycystic ovarian syndrome.

Polycystic ovarian syndrome (PCOS) is one of the most common endocrinological disorders affecting between 6 to 20% of reproductive aged women. However, the etiology of PCOS is still unclear. Epidermal growth factor receptor (EGFR) plays a critical role in the growth and development of ovarian follicles. In our previous study, we showed that the expression level of EGFR was significantly higher in the cumulus granulosa cells from women with PCOS than that of normal women, suggesting that EGFR may play a potential role in the pathogenesis of PCOS. The present study further evaluated the association between EGFR and PCOS through both in clinical observation and animal experiments. We firstly validated the differential expression of EGFR in cumulus granulosa cells between PCOS patients and normal subjects by qRT-PCR and immunofluorescence staining. Then we generated a mouse model (n=20) of PCOS by injecting dehydroepiandrosterone (DHEA). The PCOS mice were then injected with an E corpus GFR inhibitor (AG1478) (n=10), which significantly improved the sex hormone levels in the estrous cycle stage, and the serum levels of LH, FSH and testosterone were compared with the PCOS mice without EGFR inhibitor treatment (n=10). Decreasing the expression level of EGFR in the PCOS mice also improved the ovulatory function of their ovaries which was indicated by the multifarious follicle stage in these mice as compared with the PCOS mice without EGFR inhibitor treatment. Also, the number of corpopa lutea were higher in the control group and the EGFR inhibitor treated group than in the PCOS group. The sex hormone levels and reproductive function were not significantly different between the control mice and the PCOS mice treated with the EGFR inhibitor. Our results demonstrated that EGF/EGFR signaling affected the proliferation of cumulus granulosa cells, oocyte maturation and meiosis, and played a potential role in the pathogenesis of PCOS. Therefore, the selective inhibition of EGFR may serve as a novel strategy for the clinical management of PCOS.

Exome-Sequencing Identifies Novel Genes Associated with Recurrent Pregnancy Loss in a Chinese Cohort.

Recurrent pregnancy loss (RPL) is a common reproductive problem affecting around 5% of couples worldwide. At present, about half of RPL cases remained unexplained. Previous studies have suggested an important role for genetic determinants in the etiology of RPL. Here, we performed whole-exome sequencing (WES) analysis on 100 unrelated Han Chinese women with a history of two or more spontaneous abortions. We identified 6736 rare deleterious nonsynonymous variants across all patients. To focus on possible candidate genes, we generated a list of 95 highly relevant genes that were functionally associated with miscarriage according to human and mouse model studies, and found 35 heterozygous variants of 28 RPL-associated genes in 32 patients. Four genes (FOXA2, FGA, F13A1, and KHDC3L) were identified as being strong candidates. The FOXA2 nonsense variant was for the first time reported here in women with RPL. FOXA2 knockdown in HEK-293T cells significantly diminished the mRNA and protein expression levels of LIF, a pivotal factor for maternal receptivity and blastocyst implantation. The other genes, with 29 variants, were involved in angiogenesis, the immune response and inflammation, cell growth and proliferation, which are functionally important processes for implantation and pregnancy. Our study identified several potential causal genetic variants in women with RPL by WES, highlighting the important role of genes controlling coagulation, confirming the pathogenic role of KHDC3L and identifying FOXA2 as a newly identified causal gene in women with RPL.

Aberrant DNA methylation in the PAX2 promoter is associated with Müllerian duct anomalies.

PURPOSE: Abnormalities during Müllerian duct and female reproductive tract formation during embryonic development result in Müllerian duct anomalies (MDA). Previous studies have identified a role for mutations in related genes and DNA copy number variation (CNV). However, the correlation between gene methylation and MDA remains to be understood. METHODS: Endometrial tissues were collected from patients with septate (n = 23) or normal uterus (n = 28). We detected the methylation status of CpG sites and mRNA levels of nine candidate genes, including HOXA10, EMX2, TP63, ITGB3, PAX2, LHX1, GSC, WNT4, and H19, using MethyTarget and quantitative real-time polynucleotide chain reaction (qRT-PCR), respectively RESULTS: Compared with healthy controls, we detected three hypomethylated CpG sites (P < 0.05) and increased mRNA levels of PAX2 (P < 0.05) in individuals with MDA. HOXA10, EMX2, TP63, ITGB3, LHX1, and GSC had 1, 1, 2, 1, 5, and 2 differentially methylated CpG sites (P < 0.05), respectively, but there were no significant differences in their mRNA levels (P > 0.05). WNT4 and H19 did not show differences in methylation (P > 0.05) and mRNA levels (P > 0.05). CONCLUSIONS: Aberrant DNA methylation within the promoter of PAX2 may contribute to the development of MDA by regulating its gene expression. However, the methylation status of HOXA10, EMX2, TP63, ITGB3, LHX1, GSC, WNT4, and H19, may not contribute to the development of MDA.

Peak-power-clamping in an all-polarization-maintaining Q-switched mode-locking fiber laser.

We report the peak-power-clamping (PPC) effect in a polarization-maintaining (PM) Q-switched mode locking fiber laser. The laser cavity with a compact and stable all-PM fiber configuration can clearly demonstrate three different output states including normal Q-switching, PPC Q-switching, and PPC Q-switched mode-locking (QML) with the increasing pump power. To the best of our knowledge, it is the first time that PPC effect is successfully obtained and analyzed from the Q-switching to QML. This research extends the theory of PPC in pulsed lasers and reveals the potential to achieve ultra-high pulse energy.

Modulation format identification enabled by the digital frequency-offset loading technique for hitless coherent transceiver.

We propose a blind and fast modulation format identification (MFI) enabled by the digital frequency-offset (FO) loading technique for hitless coherent transceiver. Since modulation format information is encoded to the FO distribution during digital signal processing (DSP) at the transmitter side (Tx), we can use the fast Fourier transformation based FO estimation (FFT-FOE) method to obtain the FO distribution of individual data block after constant modulus algorithm (CMA) pre-equalization at the receiver side, in order to realize non-data-aided (NDA) and fast MFI. The obtained FO can be also used for subsequent FO compensation (FOC), without additional complexity. We numerically investigate and experimentally verify the proposed MFI with high accuracy and fast format switching among 28 Gbaud dual-polarization (DP)-4/8/16/64QAM, time domain hybrid-4/16QAM, and set partitioning (SP)-128QAM. In particular, the proposed MFI brings no performance degradation, in term of tolerance of amplified spontaneous emission (ASE) noise, laser linewidth, and fiber nonlinearity. Finally, a hitless coherent transceiver enabled by the proposed MFI with switching-block of only 2048 symbols is demonstrated over 1500 km standard single mode fiber (SSMF) transmission.

Polymorphisms of F2, PROC, PROZ, and F13A1 Genes are Associated With Recurrent Spontaneous Abortion in Chinese Han Women.

Mutations of hemostasis/coagulation-related genes have been speculated to cause recurrent spontaneous abortion (RSA). This study investigated the genetic association between the polymorphisms of factor V (F5), factor II (F2), antithrombin (SERPINC1), protein C (PROC), protein S (PROS1), protein Z (PROZ), factor XIII (F13A1), and carboxypeptidase B2 (CPB2) genes and RSA. The 426 patients with RSA and 444 controls were recruited in this study, and single-nucleotide polymorphisms (SNPs) were analyzed by using SNPscan technology. Genotype and allele frequencies of rs3136520 in F2, rs3024731 in PROZ, and rs1050782 in F13A1 showed statistically significant differences between the 2 groups. TT genotype of rs3136520 ( P = .031, odds ratio [OR] = 0.986, 95% confidence interval [CI] = 0.976-0.997) and AA genotype of rs2069906 in PROC ( P = .021, OR = 0.114, 95% CI = 0.014-0.902) in their recessive models and AG + GG variants of rs1050782 ( P = .007, OR = 0.681, 95% CI = 0.516-0.899) in the dominant model might be associated with the reduced risk of RSA. AT + TT variants of rs3024731 ( P = .010, OR = 1.479, 95% CI = 1.098-1.994) may increase disease susceptibility in dominant model. Haplotype analysis of rs3024731 and rs3024735 in PROZ displayed that the AA and TG haplotype were inclined to decrease and increase the risk of RSA, respectively. These results suggested that rs3136520, rs2069906, rs3024731, and rs1050782 may have a significant association with the genetic susceptibility of RSA in Chinese Han women.

Genetic association between PAX2 and mullerian duct anomalies in Han Chinese females.

PURPOSE: The study aims to investigate the genetic association between paired box gene 2 (PAX2) and mullerian duct anomalies (MDA) in Chinese Han females. METHODS: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to identify the genotypes of three tag single nucleotide polymorphisms (SNPs) in PAX2 in 362 MDA cases and 406 controls. RESULTS: We found that one tag SNP (rs12266644) of PAX2 was associated with susceptibility to MDA. The genotype distributions of the SNP rs12266644 have a statistically significant difference in the MDA patients and controls with a p value = 0.008. In the dominant model, we also observed that the GT + TT genotype increased the risk for MDA (p = 0.015, OR = 1.637, 95 % CI = 1.096-2.443). CONCLUSION: The polymorphism rs12266644 of PAX2 might be a risk factor for MDA in Chinese Han females.

The miR-449b polymorphism, rs10061133 A>G, is associated with premature ovarian insufficiency.

OBJECTIVE: To determine if the miR-449b polymorphism, rs10061133 A>G, is associated with premature ovarian insufficiency (POI) pathogenesis. METHODS: From January 2011 to December 2014, a total of 148 individuals with POI and 225 age-matched controls were collected from the Center for Reproductive Medicine, 1st Affiliated Hospital of Anhui Medical University (Hefei, China). Genotyping of miR-449b rs1006113 was performed using matrix-assisted laser desorption ionization time-of-flight-based mass spectrometry. RESULTS: Rs10061133 A>G is a highly conserved SNP locus in the mature area of miR-449b. Association analysis shows that the rs10061133 AA genotype is a risk factor for POI. CONCLUSIONS: Our study provides the first evidence that the miR-449b rs10061133 AA genotype is associated with POI risk.

Genetic analysis of DACT1 in 100 Chinese Han women with Müllerian duct anomalies.

Dapper antagonist of catenin-1 (DACT1) plays an important role in embryogenesis and organogenesis of the female reproductive tract in mouse models. The aim of this study was to investigate the association between DACT1 mutations and human Müllerian duct anomalies (MDA). One hundred clinically well-defined Chinese Han patients with MDA and 200 healthy controls were recruited in this study. All four exons coding for DACT1 were amplified and sequenced. A missense mutation (c.G1084A, p.V362M) was identified in a patient who had a didelphic uterus and was absent from the control group. This variant changed the hydrophilicity of the amino acid residue and was predicted to be deleterious to the structure and function of DACT1 protein. The data indicate that the p.V362M mutation of DACT1 may be an underlying cause of MDA.