H2 S catalysed by CBS regulates testosterone synthesis through affecting the sulfhydrylation of PDE.

Testosterone deficiency resulted in increased mortality in men. Our previous work found that hydrogen sulphide (H2 S) significantly alleviated the spermatogenesis disorder. To investigate whether H2 S could regulate testosterone synthesis and the relative signalling pathways. Disorder model of testosterone synthesis was constructed in vitro and in vivo. The cell viability was detected using CCK-8 method. The concentration of H2 S and testosterone were examined using ELISA kits. The relative mRNA and protein expression of CBS, PDE4A, PDE8A and proteins related to testosterone synthesis were detected by RT-qPCR and western blotting. PAS staining was used to detect the inflammatory status of testis. The sulfhydryl level of PDE4A and PDE8A was determined by Biotin Switch Technique. CBS overexpression inhibited while knockdown promoted LPS + H2 O2 induced injury in testosterone synthesis of MLTC-1 cells, though regulating the level of H2 S. The LPS + H2 O2 induced inhibition on cAMP and p-PKA was recovered by CBS overexpression, while addition of the specific inhibitor of PKA had opposite effects. CBS overexpression alleviated the inflammation status in testis and promoted the expression of StAR, P450scc, P450c17 and 3ß-HSD. CBS could also exhibit its protective role through promoting sulfhydrylation of PDE4A and PDE8A. H2 S catalysed by CBS could recover testosterone synthesis in vitro and in vivo through inhibiting PDE expression via sulfhydryl modification and activating cAMP/PKA pathway.

METTL3-mediated m6A methylation negatively modulates autophagy to support porcine blastocyst development‡.

N6-methyladenosine (m6A) catalyzed by METTL3 regulates the maternal-to-zygotic transition in zebrafish and mice. However, the role and mechanism of METTL3-mediated m6A methylation in blastocyst development remains unclear. Here, we show that METTL3-mediated m6A methylation sustains porcine blastocyst development via negatively modulating autophagy. We found that reduced m6A levels triggered by METTL3 knockdown caused embryonic arrest during morula-blastocyst transition and developmental defects in trophectoderm cells. Intriguingly, overexpression of METTL3 in early embryos resulted in increased m6A levels and these embryos phenocopied METTL3 knockdown embryos. Mechanistically, METTL3 knockdown or overexpression resulted in a significant increase or decrease in expression of ATG5 (a key regulator of autophagy) and LC3 (an autophagy marker) in blastocysts, respectively. m6A modification of ATG5 mRNA mainly occurs at 3'UTR, and METTL3 knockdown enhanced ATG5 mRNA stability, suggesting that METTL3 negatively regulated autophagy in an m6A dependent manner. Furthermore, single-cell qPCR revealed that METTL3 knockdown only increased expression of LC3 and ATG5 in trophectoderm cells, indicating preferential inhibitory effects of METTL3 on autophagy activity in the trophectoderm lineage. Importantly, autophagy restoration by 3MA (an autophagy inhibitor) treatment partially rescued developmental defects of METTL3 knockdown blastocysts. Taken together, these results demonstrate that METTL3-mediated m6A methylation negatively modulates autophagy to support blastocyst development.

WDR5 in porcine preimplantation embryos: expression, regulation of epigenetic modifications and requirement for early development†.

WD repeat-containing protein 5 (WDR5), a member of conserved WD40 protein family, is an essential component of the mixed lineage leukemia (MLL) complexes, which are crucial for numerous key biological processes including methylation of histone H3 lysine 4 (H3K4), self-renewal of embryonic stem cells, and formation of induced pluripotent stem cells. The expression pattern and functional role of WDR5 during porcine preimplantation embryonic development, however, remain unknown. Our results showed that the transcripts and protein of WDR5 exhibited stage-specific expression pattern in porcine early embryos. Moreover, blastocyst rate and total cell number per blastocyst were reduced by RNAi-mediated silencing of WDR5 or pharmacological inhibition of WDR5. Knockdown of WDR5 also disturbed the expression of several pluripotency genes. Interestingly, tri-methylation of H3K4 (H3K4me3) level was dramatically increased by WDR5 depletion. Further analysis revealed that loss of MLL3 phenocopied WDR5 knockdown, triggering increased H3K4me3 level. Simultaneously, WDR5 depletion significantly decreased the levels of histone H4 lysine 16 acetylation (H4K16ac) and its writer males absent on the first (MOF). Last but not least, WDR5 knockdown induced DNA damage and DNA repair defects during porcine preimplantation development. Taken together, results of described studies establish that WDR5 plays a significant role in porcine preimplantation embryos probably through regulating key epigenetic modifications and genome integrity.

Effect of follicle size on pregnancy outcomes in patients undergoing first letrozole-intrauterine insemination.

BACKGROUND: Letrozole has been proven to be an effective method for inducing ovulation. However, little attention has been paid to whether the lead follicle size will affect the success rate of intrauterine insemination (IUI) with ovulation induction with alone letrozole. Therefore, we hope to investigate the effect of dominant follicle size on pregnancy outcomes on human chorionic gonadotropin (hCG) day of the first letrozole-IUI. METHODS: A retrospective cohort study design was employed. We included patients with anovulation or unexplained infertility undergoing first IUI treatment with letrozole for ovarian stimulation. According to the dominant follicle size measured on the day of hCG trigger, patients were divided into six groups (≤ 18 mm, 18.1-19.0 mm, 19.1-20.0 mm, 20.1-21.0 mm, 21.1-22.0 mm, > 22 mm). Logistic models were used for estimating the odds ratios (ORs) with their 95% confidence interval (CIs) for achieving a clinical pregnancy or a live birth. A restricted cubic spline was drawn to explore the nonlinear relationship between follicle size and IUI outcomes. RESULTS: A total of 763 patients underwent first letrozole-IUI cycles in our study. Fisher exact test showed significant differences among the six follicle-size groups in the rates of pregnancy, clinical pregnancy and live birth (P < 0.05 in each group). After adjusting the potential confounding factors, compared with the follicles ≤ 18 mm in diameter group, 19.1-20.0 mm, 20.1-21.0 mm groups were 2.3 or 2.56 times more likely to get live birth [adjusted OR = 2.34, 95%CI (1.25-4.39); adjusted OR = 2.56, 95% CI (1.30-5.06)]. A restricted cubic spline showed an inverted U-shaped relationship between the size of dominant follicles and pregnancy rate, clinical pregnancy rate, and live birth rate, and the optimal follicle size range on the day of hCG trigger was 19.1-21.0 mm. When the E2 level on the day of hCG trigger was low than 200 pg/mL, the clinical pregnancy rates of 19.1-20.0 mm, 20.1-21.0 mm groups were still the highest. CONCLUSIONS: The optimal dominant follicle size was between 19.1 and 21.0 mm in hCG-triggered letrozole-IUI cycles. Either too large or too small follicles may lead to a decrease in pregnancy rate. Using follicle size as a predicator of pregnancy outcomes is more meaningful when estrogen on the day of hCG trigger is less than 200 pg/ml.

DTLR-CS: Deep tensor low rank channel cross fusion neural network for reproductive cell segmentation.

In recent years, with the development of deep learning technology, deep neural networks have been widely used in the field of medical image segmentation. U-shaped Network(U-Net) is a segmentation network proposed for medical images based on full-convolution and is gradually becoming the most commonly used segmentation architecture in the medical field. The encoder of U-Net is mainly used to capture the context information in the image, which plays an important role in the performance of the semantic segmentation algorithm. However, it is unstable for U-Net with simple skip connection to perform unstably in global multi-scale modelling, and it is prone to semantic gaps in feature fusion. Inspired by this, in this work, we propose a Deep Tensor Low Rank Channel Cross Fusion Neural Network (DTLR-CS) to replace the simple skip connection in U-Net. To avoid space compression and to solve the high rank problem, we designed a tensor low-ranking module to generate a large number of low-rank tensors containing context features. To reduce semantic differences, we introduced a cross-fusion connection module, which consists of a channel cross-fusion sub-module and a feature connection sub-module. Based on the proposed network, experiments have shown that our network has accurate cell segmentation performance.

Analysis of selected sperm samples by a computer-assisted system with high frame rate: A prospective study.

Background and Aims: Due to the rapid motility of the selected sperm, sperm parameters cannot be accurately determined by the manual method. So, the application of a computer-assisted sperm analysis system with a high frame rate (HFR-CASA, 85 Hz) in sperm selection is investigated. Methods: A total of 177 semen samples were collected for sperm selection with density gradient centrifugation. Then, the manual method and HFR-CASA method will be used to observe and analyze the sperm concentration, motility, and percentage of progressively motile sperm (PR) of the selected sperm samples. The quality control of sperm concentration was performed with microballoons. Two selected sperm samples were analyzed 10 times repeatedly to evaluate the accuracy of the HFR-CASA. Results: The results of microballoons analyzed with the HFR-CASA were in control. The coefficients of variation of sperm concentration, motility, and PR from two selected sperm samples were all below 10%. The results of 177 selected sperm samples analyzed by the manual method and HFR-CASA showed that although there were significant positive correlations in sperm concentration, motility, and PR between them (p < 0.001), the manual method significantly underestimated sperm concentration (p = 0.002) but overestimated sperm motility and PR (p < 0.001). When sperm concentration was below 50 × 106/mL, the manual method significantly overestimated sperm concentration (p < 0.05). However, when sperm concentration was more than 100 × 106/mL, the manual method significantly underestimated sperm concentration (p < 0.001). Regardless of sperm concentration, the manual method consistently overestimated sperm motility and PR (p < 0.001). When sperm concentration was more than 20 × 106/mL, there was no correlation in sperm PR between them (p > 0.05). When sperm concentration was below 50 × 106/mL, the correct rate of captured sperm by the HFR-CASA was more than 98%. Conclusion: The HFR-CASA method is more accurate than the manual method in analyzing the selected sperm samples.

Quantitative phosphoproteomics reveals GSK3A substrate network is involved in the cryodamage of sperm motility.

During sperm cryopreservation, the most significant phenotype of cryodamage is the decrease in sperm motility. Several proteomics studies have already been performed to search for key regulators at the protein level. However, sperm functions are known to be highly regulated by phosphorylation signaling. Here, we constructed a quantitative phosphoproteome to investigate the expression change of phosphorylated sites during sperm cryopreservation. A total of 3107 phosphorylated sites are identified and 848 of them are found to be significantly differentially expressed (DE). Bioinformatics analysis showed that the corresponding genes of these regulated sites are highly associated with sperm motility, providing a connection between the molecular basis and the phenotype of cryodamage. We then performed kinase enrichment analysis and successfully identified glycogen synthase kinase-3α (GSK3A) as the key kinase that may play an important role in the regulation of sperm motility. We further constructed a GSK3A centric network that could help us better understand the molecular mechanism of cryodamage in sperm motility. Finally, we also verified that GSK3A was abnormally activated during this process. The presented phosphoproteome and functional associations provide abundant research resources for us to learn the regulation of sperm functions, as well as to optimize the cryoprotectant for sperm cryopreservation.

USP26 deubiquitinates androgen receptor (AR) in the maintenance of sperm maturation and spermatogenesis through the androgen receptor signaling pathway.

BACKGROUND: The post-translational modifications of proteins control various physiological and pathological events in cells. OBJECTIVES: In this study, we investigated the influences of the X-linked deubiquitination enzyme USP26 in mediating androgen receptor (AR) deubiquitination in the physiological events of sperm maturation and spermatogenesis through the AR signaling pathway. MATERIAL AND METHODS: The cell cycle results detected with flow cytometry (FCM) showed that both of the proteins, USP26 and AR, could facilitate the transition of G1-G2 phase in the Leydig cells (TM3). This effect also promoted the proliferation of the Leydig cells. RESULTS: The cell cycle studies performed using FCM detected that the 2 proteins, USP26 and AR, could facilitate the transition of G1-G2 phase in the Leydig cells (TM3). This effect also promoted the proliferation of the Leydig cells. Moreover, the results from co-immunoprecipitation (CO-IP), immunofluorescence and western blot assays showed that the physiological process due to USP26 interacted with AR and influenced AR deubiquitination, thus upregulating the proteins CCND1 and SPATA46 - which are associated with cell cycle progression and spermatogenesis - as well as decreasing the expression of TP73. Thus, these processes took place through the AR signaling pathway. Furthermore, the USP26 mimic plasmid transfection enhanced these activities, while, conversely, USP26 and AR inhibitor plasmid transfection suppressed the physiological events. CONCLUSIONS: Taken together, the effects of AR deubiquitinated by USP26 could modulate sperm maturation and spermatogenesis through the androgen receptor signaling pathway.

DOT1L inhibitor improves early development of porcine somatic cell nuclear transfer embryos.

Incomplete epigenetic reprogramming of the genome of donor cells causes poor early and full-term developmental efficiency of somatic cell nuclear transfer (SCNT) embryos. Previous research indicate that inhibition of the histone H3 K79 methyltransferase DOT1L, using a selective pharmacological inhibitor EPZ004777 (EPZ), significantly improved reprogramming efficiency during the generation of mouse induced pluripotent stem cells. However, the roles of DOT1L in porcine nuclear transfer-mediated cellular reprogramming are not yet known. Here we showed that DOT1L inhibition via 0.5 nM EPZ treatment for 12 or 24 h significantly enhanced the blastocyst rate of SCNT embryos and dramatically reduced the level of H3K79me2 during SCNT 1-cell embryonic development. Additionally, H3K79me2 level in the EPZ-treated SCNT embryos was similar to that in in vitro fertilized embryos, suggesting that DOT1L-mediated H3K79me2 is a reprogramming barrier to early development of porcine SCNT embryos. qRT-PCR analysis further demonstrated that DOT1L inactivation did not change the expression levels of DOT1L itself but increased the expression levels of POU5F1, LIN28, SOX2, CDX2 and GATA4 associated with pluripotency and early cell differentiation. In conclusion, DOT1L inhibitor improved early developmental efficiency of porcine SCNT embryos probably via inducing the increased expression of genes important for pluripotency and lineage specification.

TSA and BIX-01294 Induced Normal DNA and Histone Methylation and Increased Protein Expression in Porcine Somatic Cell Nuclear Transfer Embryos.

The poor efficiency of animal cloning is mainly attributed to the defects in epigenetic reprogramming of donor cells' chromatins during early embryonic development. Previous studies indicated that inhibition of histone deacetylases or methyltransferase, such as G9A, using Trichostatin A (TSA) or BIX-01294 significantly enhanced the developmental efficiency of porcine somatic cell nuclear transfer (SCNT) embryos. However, potential mechanisms underlying the improved early developmental competence of SCNT embryos exposed to TSA and BIX-01294 are largely unclear. Here we found that 50 nM TSA or 1.0 µM BIX-01294 treatment alone for 24 h significantly elevated the blastocyst rate (P < 0.05), while further improvement was not observed under combined treatment condition. Furthermore, co-treatment or TSA treatment alone significantly reduced H3K9me2 level at the 4-cell stage, which is comparable with that in in vivo and in vitro fertilized counterparts. However, only co-treatment significantly decreased the levels of 5mC and H3K9me2 in trophectoderm lineage and subsequently increased the expression of OCT4 and CDX2 associated with ICM and TE lineage differentiation. Altogether, these results demonstrate that co-treatment of TSA and BIX-01294 enhances the early developmental competence of porcine SCNT embryos via improvements in epigenetic status and protein expression.

Effects of melatonin on maturation, histone acetylation, autophagy of porcine oocytes and subsequent embryonic development.

Melatonin (MLT) is an endogenous hormone with roles in animal germ cell development. However, the effect of MLT on porcine oocyte maturation and its underlying mechanisms remain largely unknown. Here, we investigated the effects of exogenous MLT on oocyte maturation, histone acetylation, autophagy and subsequent embryonic development. We found that 1 nmol/L MLT supplemented in maturation medium was the optimal concentration to promote porcine oocyte maturation and subsequent developmental competence and quality of parthenogenetic embryos. Interestingly, the beneficial effects of 1 nmol/L MLT treatment on porcine oocyte maturation and embryo development were mainly attributed to the first half period of in vitro maturation. Simultaneously, MLT treatment could also improve maturation of small follicle-derived oocytes, morphologically poor (cumulus cell layer ≤1) and even artificially denuded oocytes and their subsequent embryo development. Furthermore, MLT treatment not only could decrease the levels of H3K27ac and H4K16ac in metaphase II (MII) oocytes, but also could increase the expression abundances of genes associated with cumulus cell expansion, meiotic maturation, histone acetylation and autophagy in cumulus cells or MII oocytes. These results indicate that MLT treatment can facilitate porcine oocyte maturation and subsequent embryonic development probably, through improvements in histone acetylation and autophagy in oocytes.