Molecular human reproduction最新文献

Protamine 2 (Prm2/PRM2), together with Protamine 1 (Prm1/PRM1), constitute the two protamines found in both murine and human sperm. During spermiogenesis in haploid male germ cells, chromatin undergoes significant condensation, a phase in which most histones are replaced by a species-specific ratio of these two protamines. Altered PRM1/PRM2 ratios are associated with subfertility and infertility in both male mice and men. Notably, during histone-to-protamine exchange a small fraction of histones remains (ranging from 1% to 15%) bound to DNA. The regulatory roles of these residual histones, governed by post-translational modifications (PTMs), play a pivotal role in spermatogenesis, particularly in chromatin remodeling and epigenetic regulation of genes during sperm differentiation or even in early embryogenesis. In this study, utilizing a Prm2-deficient mouse model and conducting an analysis of sperm samples from men exhibiting either normozoospermia or atypical spermiograms, we observed alterations in the methylation and acetylation profiles of histones H3 and H4. Subsequent in- depth analysis revealed that discrepancies in protamine ratios do not significantly influence the post-translational modifications (PTMs) of histones in testicular sperm. In murine epididymal sperm, altered protamine ratios are associated with reduced acetylation of histone H4 (H4ac), a phenomenon similarly observed in ejaculated sperm from men. In particular, H4K5ac and H4K12ac were identified as the two modifications that appear to decrease as a result of reduced Prm2/PRM2 levels. Our findings reveal that Protamine 2 is necessary for the maintenance of specific histone PTMs, such as acetylation, which is essential for proper spermatogenesis and particularly for chromatin remodeling.

Infertility affects a considerable number of couples at reproductive age, with an incidence of 10-15%. Approximately 25% of cases are classified as idiopathic infertility. Often, errors during the meiotic stage appear to be related to idiopathic infertility. A crucial component during first meiotic prophase is the synaptonemal complex (SC), which plays a fundamental role in homologous chromosome pairing and meiotic recombination. In many studies with infertile patients, mutations affecting SC-coding genes have been identified. The generation of humanized models has high physiological relevance, helping to clarify the molecular bases of pathology, which in turn is essential for the development of therapeutic procedures. Here we report the generation and characterization of genetically modified mice carrying a mutation equivalent to SYCE1 c.197-2A>G, previously found in male infertile patients, aiming to determine the actual effects of this mutation on reproductive capacity and to study the underlying molecular mechanisms. Homozygous mutants were infertile. SYCE1 protein was not detected and Syce1 transcript presented minimal levels, suggesting transcript degradation underlying the infertility mechanism. Additionally, homozygous mutants showed impaired homologous chromosome synapsis, meiotic arrest before the pachytene stage, and increased apoptosis of meiotic cells. This study validates the variant as pathogenic and causative of infertility, since the observed dramatic phenotype was attributable to this single homozygous point mutation, when compared to WT and heterozygous littermates. Moreover, although this homozygous point mutation has been only found in infertile men thus far, we anticipate that if it were present in women, it would cause infertility as well, as homozygous female mice also exhibited an infertility phenotype.

Recent advances in embryology have shown that the sister blastomeres of two-cell mouse and human embryos differ reciprocally in potency. An open question is whether the blastomeres became different as opposed to originating as different. Here we wanted to test two relevant but conflicting models: one proposing that each blastomere contains both animal and vegetal materials in balanced proportions because the plane of first cleavage runs close to the animal-vegetal axis of the fertilized oocyte (meridional cleavage); and the other model proposing that each blastomere contains variable proportions of animal and vegetal materials because the plane of the first cleavage can vary - up to an equatorial orientation - depending on the topology of fertilization. Therefore, we imposed the fertilization site in three distinct regions of mouse oocytes (animal pole, vegetal pole, equator) via ICSI. After the first zygotic cleavage, the sister blastomeres were dissociated and subjected to single-cell transcriptome analysis, keeping track of the original pair associations. Non-supervised hierarchical clustering revealed that the frequency of correct pair matches varied with the fertilization site (vegetal pole > animal pole > equator), thereby, challenging the first model of balanced partitioning. However, the inter-blastomere differences had similar signatures of gene ontology across the three groups, thereby, also challenging the competing model of variable partitioning. These conflicting observations could be reconciled if animal and vegetal materials were partitioned at the first cleavage: an event considered improbable and possibly deleterious in mammals. We tested this occurrence by keeping the fertilized oocytes immobilized from the time of ICSI until the first cleavage. Image analysis revealed that cleavage took place preferentially along the short (i.e. equatorial) diameter of the oocyte, thereby partitioning the animal and vegetal materials into the two-cell blastomeres. Our results point to a simple mechanism by which the two sister blastomeres start out as different, rather than becoming different.

Adenomyosis is a chronic, estrogen-driven disorder characterized by the presence of endometrial glands and stroma within the myometrium. Despite its significant impact on reproductive health and quality of life, the pathogenesis of the disease remains unclear. Both the glandular and stromal compartments of eutopic endometrium from women with adenomyosis show alterations compared to healthy subjects. However, the molecular mechanisms driving crosstalk between stromal cells and epithelial glands, along with paracrine signaling underlying lesion development and progression, are still poorly understood. Exosomes, small cell-derived carriers and microRNAs, namely non-coding RNA molecules, are crucial to intercellular communication within the endometrium and may elucidate interactions between the two compartments that contribute to adenomyotic lesion formation. To our knowledge, this is the first foundational study to comprehensively isolate and characterize stroma-derived exosomes from women with adenomyosis. Exosome isolation by means of differential ultracentrifugation was validated in 22 samples, including 11 healthy subjects and 11 women with adenomyosis, using nanoparticle tracking analysis, transmission electron microscopy, and flow cytometry. Profiling of microRNA in secreted exosomes revealed 10 microRNAs with significantly altered expression in adenomyosis subjects during the menstrual phase compared to controls. Thorough investigations into menstruation-specific molecular mechanisms, as well as predicted target genes and enriched pathways of exosomal microRNAs, offer promising insights into the pathogenesis of adenomyosis, shedding light on the potential mechanisms underlying stromal cell signaling and adenomyotic lesion establishment. This work does, however, have certain drawbacks, including modest sample size and limited representation due to a lack of readily available endometrial biopsies in the menstrual phase. Having done the groundwork in this study, future research should seek to validate these findings in larger cohorts and apply functional assays. Indeed, our findings can serve as a resource to elucidate the role of menstruation-specific stroma-derived microRNA-mediated signaling and its potential impact on adenomyosis development.

Biphasic IVM can be offered as a patient-friendly alternative to conventional ovarian stimulation in IVF patients predicted to be hyper-responsive to ovarian stimulation. However, cumulative live birth rates after IVM per cycle are lower than after conventional ovarian stimulation for IVF. In different animal species, supplementation of IVM media with oocyte-secreted factors (OSFs) improves oocyte developmental competence through the expression of pro-ovulatory genes in cumulus cells. Whether the addition of OSFs in human biphasic IVM culture impacts the transcriptome of oocytes and cumulus cells retrieved from small antral follicles in minimally stimulated non-hCG-triggered IVM cycles remains to be elucidated. To answer this, human cumulus-oocyte complexes (COCs) that were fully surrounded by cumulus cells or partially denuded at the time of retrieval were cultured in a biphasic IVM system either without or with the addition of pro-cumulin, a GDF9:BMP15 heterodimer. Oocytes and their accompanying cumulus cells were collected separately, and single-cell RNA-seq libraries were generated. The transcriptomic profile of cumulus cells revealed that pro-cumulin upregulated the expression of genes involved in cumulus cell expansion and proliferation while downregulating steroidogenesis, luteinization, and apoptosis pathways. Moreover, pro-cumulin modulated the immature oocyte transcriptome during the pre-maturation step, including regulating translation, apoptosis, and mitochondria remodeling pathways in the growing germinal vesicle oocytes. The addition of pro-cumulin also restored the transcriptomic profile of matured metaphase II oocytes that were partially denuded at collection. These results suggest that cumulus cell and oocyte transcriptome regulation by pro-cumulin may increase the number of developmentally competent oocytes after biphasic IVM treatment. Future studies should assess the effects of pro-cumulin addition in human biphasic IVM at the proteomic level and the embryological outcomes, particularly its potential to enhance outcomes of oocytes that are partially denuded at COC collection.

In patients with mosaic Turner syndrome, the ovarian somatic cells (granulosa and stromal cells) display a high level of aneuploidy with a 45,X karyotype, which may affect gene expression in the ovary and contribute to their reduced fertility. The aim of the current research is to study the effect of aneuploidy of somatic ovarian cells on gene expression in ovarian cortex stromal cells and small ovarian follicles from mosaic (45,X/46,XX) Turner syndrome patients. To this end, ovarian cortical tissue was obtained by laparoscopic surgery from eight mosaic Turner syndrome patients (aged 5-19 years) and eight controls (aged 6-18 years). The tissue was fractionated to obtain purified follicles and stromal cells. Part of the purified fractions was used to determine the X chromosomal content of ovarian cells of Turner syndrome patients by interphase FISH, while the remaining part was used to compare the gene expression profile of these cells to controls. The results demonstrated that high level 45,X haploidy in cortical stromal cells of Turner syndrome patients had no effect on gene expression, gross morphology of the ovary, or histological appearance of the cortex compared to controls. Gene expression analysis of purified small follicles of Turner syndrome patients with mainly 45,X granulosa cells revealed aberrant expression of 11 genes. Of these, six were upregulated (CD24, TLR1, EPHA2, PLXND1, ST6GALNAC5, and NOX4) while five genes (CRYAB, DLX1, PCYT2, TNFRSF8, and CA12) were downregulated compared to follicles of controls. Interestingly, the overexpressed genes in these small follicles were all associated with more advanced stages of follicular development. The consequences of this abnormal gene expression in follicles for Turner syndrome patients remain to be investigated, but they are likely to affect fertility.

Mammalian target of rapamycin (mTOR) inhibitors have been used clinically as anticancer and immunosuppressive agents for over 20 years, demonstrating their safety after long-term administration. These inhibitors exhibit various effects, including inhibition of cell proliferation, interaction with the oestrogen and progesterone pathways, immunosuppression, regulation of angiogenesis, and control of autophagy. We evaluated the potential of mTOR inhibitors as therapeutic agents for endometriosis, examined the secondary benefits related to reproductive function, and assessed how their side effects can be managed. We conducted a thorough review of publications on the role of the mTOR pathway and the effectiveness of mTOR inhibitors in endometriosis patients. These results indicate that the mTOR pathway is activated in endometriosis. Additionally, mTOR inhibitors have shown efficacy as monotherapies for endometriosis. They may alleviate resistance to hormonal therapy in endometriosis, suggesting a potential synergistic effect when used in combination with hormonal therapy. The potential reproductive benefits of mTOR inhibitors include decreased miscarriage rates, improved implantation, and prevention of age-related follicular loss and ovarian hyperstimulation syndrome. Activation of the mTOR pathway has also been implicated in the malignant transformation of endometriosis. Preclinical studies suggest that the dosage of mTOR inhibitors needed for treating endometriosis may be lower than that required for anticancer or immunosuppressive therapy, potentially reducing dosage-dependent side effects. In conclusion, while mTOR inhibitors, which allow for pregnancy during oral administration, show potential for clinical use in all stages of endometriosis, current evidence is limited to preclinical studies, and further research is needed to confirm clinical effectiveness.

Endometrial collagen I undergoes dynamic degradation and remodelling in response to endometrial stromal cell (ESC) decidualization and embryo implantation. However, excessive collagen I deposition in the endometrium during the implantation window may impair decidualization, causing embryo implantation failure in patients with endometriosis (EMS). We found that endometrial collagen I expression during the mid-secretory phase was increased in the EMS group of patients. Collagen I stimulation resulted in decreased expression of the decidualization markers prolactin and insulin-like growth factor binding protein-1 in ESCs, impeding ESC transformation to a decidual morphology and decreasing the blastocyst-like spheroid expansion area in vitro. Treatment with extracellular vesicles (EVs) derived from the ectopic ESCs of EMS patients (EMS-EVs) increased collagen I expression in vivo and in vitro and decreased the blastocyst-like spheroid expansion area. Furthermore, EV microRNA (miRNA) sequencing revealed that there were 40 upregulated and 77 downregulated miRNAs in EMS-EVs when compared to the EVs derived from ESCs in the endometrium of control patients (CTL-EVs), including increased expression of miR-25-3p that targets phosphatase and tensin homolog (PTEN). We also found that PTEN expression was decreased and p-Akt expression was increased in the endometrium of EMS patients and EMS-EV-treated ESCs. miR-25-3p transfected ESCs exhibited increased collagen I, decreased PTEN, and increased p-Akt. Additionally, an EV uptake study further showed that EMS-EVs were preferentially taken up by ESCs rather than by endometrial epithelial cells. These results suggest that EMS-EVs encapsulating miR-25-3p might be preferentially taken up by eutopic ESCs where they may induce endometrial collagen I deposition to impair ESC decidualization in EMS.

Currently, there are no placenta-targeted treatments to alter the in utero environment for administration to pregnant women who receive a diagnosis of fetal growth restriction (FGR). Water-soluble polymers have a distinguished record of clinical relevance outside of pregnancy. We have demonstrated the effective delivery of polymer-based nanoparticles containing a non-viral human insulin-like growth factor 1 (IGF1) transgene to correct placental insufficiency in small animal models of FGR. Our goals were to extend these studies to a proof-of-concept study in the pregnant macaque, establish feasibility of nanoparticle-mediated gene therapy delivery to trophoblasts, and investigate the acute maternal, placental, and fetal responses to treatment. Pregnant macaques underwent ultrasound-guided intraplacental injections of nanoparticles (GFP- or IGF1-expressing plasmid under the control of the trophoblast-specific PLAC1 promoter complexed with a HPMA-DMEAMA co-polymer) at approximately gestational day 100 (term = 165 days). Fetectomy was performed 24 h (GFP; n = 1), 48 h (IGF1; n = 3) or 10 days (IGF1; n = 3) after nanoparticle delivery. Routine pathological assessment was performed on biopsied maternal tissues and placental and fetal tissues. Maternal blood was analyzed for complete blood count (CBC), immunomodulatory proteins and growth factors, progesterone (P4), and estradiol (E2). Placental ERK/AKT/mTOR signaling was assessed using Western blot and qPCR. Fluorescent microscopy and in situ hybridization confirmed placental uptake and transient transgene expression in villous syncytiotrophoblast. No off-target expression was observed in either maternal or fetal tissues. Histopathological assessment of the placenta recorded observations not necessarily related to the IGF1 nanoparticle treatment. In maternal blood, CBCs, P4, and E2 remained within the normal range for pregnant macaques across the treatment period. Changes to placental ERK and AKT signaling at 48 h and 10 days after IGF1 nanoparticle treatment indicated an upregulation in placental homeostatic mechanisms to prevent overactivity in the normal pregnancy environment. The lack of adverse maternal reaction to nanoparticle-mediated IGF1 treatment, combined with changes in placental signaling to maintain homeostasis, indicates no deleterious impact of treatment during the acute phase of study.

Endometrial receptivity is crucial for successful embryo implantation during early pregnancy. The human endometrium undergoes remodeling within each menstrual cycle to prepare or become receptive to an implanting blastocyst in the mid-secretory phase. However, the mechanisms behind these changes are not fully understood. Recently, using hormone-treated endometrial organoids to model receptivity, we identified that the transcriptional regulator WD-repeat-containing protein-61 (WDR61) was reduced in organoids derived from infertile women. In this study, we aimed to determine the role of WDR61 in endometrial receptivity. Here, we demonstrated that WDR61 immunolocalizes in the nuclei and cytosol of endometrial glandular epithelium, luminal epithelium, and stroma. The staining intensity of WDR61 was significantly higher during the receptive mid-secretory phase compared to the non-receptive proliferative phase in fertile women. In a functional experiment to model blastocyst adhesion to the endometrial epithelium, we found that adhesion of cytotrophoblast progenitor spheroids was blocked when siRNA was used to knockdown WDR61 in primary endometrial epithelial cells. Similarly, in Ishikawa cells (a receptive human endometrial epithelial cell line), siRNA knockdown of WDR61 significantly reduced the cell adhesive and proliferative capacities. qPCR revealed that WDR61 knockdown reduced expression of key genes involved in receptivity including HOXD10, MMP2, and CD44. Chromatin immunoprecipitation sequencing demonstrated that WDR61 directly targeted 2022 genes in Ishikawa cells, with functions including focal adhesion, intracellular signaling and epithelial-mesenchymal transition. Overall, these findings suggest that WDR61 promotes endometrial receptivity by modulating epithelial cell focal adhesions, proliferation, and epithelial-mesenchymal transition.