No abstract

Maternal-effect genes (MEGs) play an important role in maintaining the survival and development of mammalian embryos at the cleavage stage after fertilization. Despite long-term efforts, the MEGs that regulate preimplantation embryo development remain largely unknown. Here, using Whole-exome sequencing (WES) and homozygosity mapping, we identified a potential candidate gene associated with early embryo development: nucleoporin37 (NUP37), a nucleoporin gene that encodes a member of the nuclear pore complexes (NPCs) and regulates nuclear pore permeability and nucleocytoplasmic transport. Moreover, we determined the temporal and spatial expression patterns of Nup37 in mouse oocytes and early embryos, and explored the role of NUP37 in oocyte maturation and preimplantation embryo development. Immunoprecipitation assays confirmed that YAP1 binds to TEAD4 and NUP37. Furthermore, Nup37 gene knockdown reduced the nuclear import of YAP1 and downregulated the expression of YAP1-TEAD pathway downstream genes Rrm2 and Rpl13 in early embryos. Our study provides evidence that maternal NUP37 contributes to the nuclear import of YAP1 and then activates the YAP1-TEAD pathway, a signaling pathway essential for zygotic genome activation (ZGA). Nup37 may be a key gene involved in preimplantation embryo development in mammals.

Background: To study whether ILs/TNFs in the follicular fluid (FF) of women with EMs are responsible for impaired follicular development or (and) ovulation or not, and then to explore the underlying mechanisms. Methods: follicular fluid (containing cumulus granulosa cells) was collected from women with EM and male factor infertility at our Clinical Reproductive Medicine Center, and peritoneal fluid was collected from the above patients with EMs. The expression of ovulation-related genes in cumulus cells was analysed by RT-PCR. Mouse cumulus cells expansion degree was assessed after cultured in follicle fluid from infertile women. Follicle fluid was detected by ELISA. Oocytectmized complex cell model was established, and cultured in vitro medium with addition of 100 IU/ml FSH. TUNEL staining was used to determine the apoptosis of cumulus cells. Then, we explored expression of P-SMAD2/3，key enzyme for retinoic acid metabolism, and methylation of SP1 binding sites in Lhcgr promoter region. Meanwhile, the P-AKT and P-catenin were assessed by Western blot. All experiments were performed independently at least three times, and data are presented as mean ± SEM. Statistical analyses were performed using Graphpad Prism 5 software p<0.05 (* and different letters) were defined as significant differences. Results: In cumulus cells, expression of genes related to ovulation decreased significantly than that in controls (P < 0.05), especially starting from LHCGR. The concentrations of IL-8 and TNF-α in follicle fluid were significantly higher in infertile women with endometriosis than in controls (P < 0.05). The function of follicle fluid and pelvic fluid of endometriosis women have changed. Addition of 500 pg/mL IL-8/TNF-α to medium did not cause significant apoptosis of cumulus cells, but inhibited P-AKT and P-β-catenin. On the other hand, expression of P-SMAD2/3 and retinoic acid production were reduced, while hypermethylation of the Sp1 binding sequence on Lhcgr promoter was identified, and Lhcgr expression was significantly reduced compared to control (P<0.05). Conclusion: Elevated IL-8/TNF-α in follicular fluid of women with endometriosis indirectly maintains Lhcgrpromoter hypermethylation through activation of P-SMAD2/3, while inhibiting AKT and β-Catenin phosphorylation, which together reduce LHCGR mRNA expression.