Notch signaling pathway in cumulus cells can be a novel marker to identify poor and normal responder IVF patients

Exome sequencing in genuine empty follicle syndrome: Novel candidate genes

OBJECTIVE(S)

Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved in an IVF cycle despite apparently normal follicular development and meticulous follicular aspiration following ovulation induction. The EFS is called genuine (gEFS) when the trigger administration is correct. The existence of gEFS is a subject of controversy, and it is quite rare with an undetermined etiology. Genetic defects in specific genes have been demonstrated to be responsible for this condition in some patients. Our objective was to identify novel genetic variants associated with gEFS.

STUDY DESIGN

We conducted a prospective observational study including 1,689 egg donors from July 2017 to February 2023. WES were performed in patients suffering gEFS.

RESULTS

Only 7 patients (0.41 %) exhibited gEFS after two ovarian stimulation cycles and we subsequently performed whole exome sequencing (WES) on these patients. Following stringent filtering, we identified 6 variants in 5 affected patients as pathogenic in new candidate genes which have not been previously associated with gEFS before, but which are involved in important biological processes related to folliculogenesis. These genetic variants included c.603_618del in HMMR, c.1025_1028del in LMNB1, c.1091-1G > A in TDG, c.607C > T in HABP2, c.100 + 2 T > C in HAPLN1 and c.3592_3593del in JAG2.

CONCLUSION

As a conclusion, we identified new candidate genes related to gEFS that expand the mutational spectrum of genes related to gEFS.This study show that WES might be an efficient tool to identify the genetic etiology of gEFS and provide further understanding of the pathogenic mechanism of gEFS.

Biomarkers Assessing the Role of Cumulus Cells on IVF Outcomes: A Systematic Review

PURPOSE

Although significant improvements in assisted reproductive technology (ART) outcomes have been accomplished, a critical question remains: which embryo is most likely to result in a pregnancy? Embryo selection is currently based on morphological and genetic criteria; however, these criteria do not fully predict good-quality embryos and additional objective criteria are needed. The cumulus cells are critical for oocyte and embryo development. This systematic review assessed biomarkers in cumulus-oocyte complexes and their association with successful IVF outcomes.

METHODS

A comprehensive search was conducted using PubMed, Embase, Scopus, and Web of Science from inception until November 2022. Only English-language publications were included. Inclusion criteria consisted of papers that evaluated genetic biomarkers associated with the cumulus cells (CCs) in humans and the following three outcomes of interest: oocyte quality, embryo quality, and clinical outcomes, including fertilization, implantation, pregnancy, and live birth rates.

RESULTS

The search revealed 446 studies of which 42 met eligibility criteria. Nineteen studies correlated genetic and biochemical biomarkers in CCs with oocyte quality. A positive correlation was reported between oocyte quality and increased mRNA expression in CCs of genes encoding for calcium homeostasis (CAMK1D), glucose metabolism (PFKP), extracellular matrix (HAS2, VCAN), TGF-β family (GDF9, BMP15), and prostaglandin synthesis (PTGS2). Nineteen studies correlated genetic and biochemical biomarkers in CCs with embryo quality. A positive correlation was reported between embryo quality and increased mRNA expression in CCs of genes encoding for extracellular matrix (HAS2), prostaglandin synthesis (PTGS2), steroidogenesis (GREM1), and decreased expression of gene encoding for hormone receptor (AMHR2). Twenty-two studies assessed genetic and biochemical biomarkers in CCs with clinical outcomes. Increased expression of genes encoding for extracellular matrix (VCAN), and TGF-β family (GDF9, BMP15) were positively correlated with pregnancy rate.

CONCLUSION

Genetic biomarkers from cumulus cells were associated with oocyte quality (CAMK1D, PFKP, HAS2, VCAN, GDF-9, BMP-15, PTGS2), embryo quality (GREM1, PTGS2, HAS2), and pregnancy rate (GDF9, BMP15, VCAN). These results might help guide future studies directed at tests of cumulus cells to devise objective criteria to predict IVF outcomes.

Potential Involvement of DNA Methylation in Hybrid Sterility in Hermaphroditic Argopecten Scallops

DNA methylation is an important epigenetic modification factor in regulating fertility. Corresponding process remains poorly investigated in hermaphroditic scallops. The interspecific F1 hybrids between the hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in hybrids obstructs the utilization of the genetic resources. However, the determination mechanism of hybrid sterility in the hermaphroditic Argopecten scallops is still unclear. In this study, the effect of DNA methylation in the hybrid sterility of hermaphroditic Argopecten scallops was explored. The results showed that the mean methylation level was higher in sterile hybrids than fertile hybrids, especially on chromosome 11 of the paternal parent. A total of 61,062 differentially methylated regions (DMRs) were identified, containing 3619 differentially methylated genes (DMGs) and 1165 differentially methylated promoters that are located in the DMRs of CG sequence context. The hyper-methylated genes were enriched into five KEGG pathways, including ubiquitin-mediated proteolysis, ECM-receptor interaction, non-homologous end-joining, notch signaling, and the mismatch repair pathways. The DMGs might induce hybrid sterility by inhibition of oogenesis and egg maturation, induction of apoptosis, increased ROS, and insufficient ATP supply. Our results would enrich the determination mechanism of hybrid sterility and provide new insights into the utilization of the genetic resources of the interspecific hybrids.

Why double ovarian stimulation in an in vitro fertilization cycle is potentially unsafe

The occurrence of two antral follicle recruitment waves in a single inter-ovulatory interval has been detected in ovaries of normal women. This data supports the claim that a double ovarian stimulation in the same cycle may benefit poor responder patients with an increased recovery of mature oocytes and good quality embryos per single cycle. The double stimulation protocol was the object of several published studies in which, surprisingly, the mechanism and the safety of the double stimulation in the same cycle were poorly addressed. We propose that in the double stimulation protocol, the first stimulation impacts more committed oocytes progenitors ready to differentiate into mature oocytes. Conversely, the protracted exposure of developmentally earlier less-committed ovarian stem cells to FSH, which occurs in the double stimulation protocol, impacts the less differentiated stem cells which take longer to differentiate into oocytes. The proposed mechanism has broad implications for the safety of the double stimulation strategy.

Effects of Notch2 on proliferation, apoptosis and steroidogenesis in bovine luteinized granulosa cells

Notch signaling pathway plays an important regulatory role in the development of mammalian follicles. This study aimed to explore the effect of Notch2 on the function of bovine follicles luteinized granulosa cells (LGCs). We detected that the coding sequence (CDS) of bovine Notch2 gene is 7416 bp, encoding 2471 amino acids (AA). The homology of Notch2 AA sequence between bovine and other species is 86.04%-98.75%, indicating high conservatism. Immunohistochemistry found that Notch2 receptor and its ligand Jagged2 localize in granulosa cells (GCs) and theca cells in bovine antral follicles. And immunofluorescence found that positive signals of Notch2 and Jagged2 overlap in bovine LGCs, speculating that Notch2 receptor may react with Jagged2 ligand to activate Notch signaling pathway and play an important role in bovine LGCs. To further investigate the function of Notch2, Notch2 gene was silenced by short hairpin RNA (shRNA) and CCK-8 analysis showed that the proliferation rate of LGCs was downregulated significantly (P < 0.01). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) showed that the mRNA expression of apoptosis related gene Bcl-2/Bax decreased (P < 0.01) and Caspase3 increased (P < 0.05), cell cycle related gene CyclinD2/CDK4 complex decreased (P < 0.01) and P21 increased (P < 0.05), steroidogenesis gene STAR and 3β-HSD decreased (P < 0.01) while CYP19A1 and CYP11A1 had no significant difference (P > 0.05). In addition, Enzyme-linked immunosorbent assay (ELISA) showed that there was no difference in estradiol (E₂) secretion (P > 0.05) while the progesterone (P₄) secretion decreased (P < 0.01). In conclusion, Notch2 plays an important role in regulating bovine LGCs development.

An in silico model using prognostic genetic factors for ovarian response in controlled ovarian stimulation: A systematic review

PURPOSE

To study the use of in silica model to better understand and propose new markers of ovarian response to controlled ovarian stimulation before IVF.

METHODS

A systematic review and in silica model using bioinformatics. After the selection of 103 papers from a systematic review process, we performed a GRADE qualification of all included papers for evidence-based quality evaluation. We included 57 genes in the silica model using a functional protein network interaction. Moreover, the construction of protein-protein interaction network was done importing these results to Cytoscape. Therefore, a cluster analysis using MCODE was done, which was exported to a plugin BINGO to determine Gene Ontology. A p value of < 0.05 was considered significant, using a Bonferroni correction test.

RESULTS

In silica model was robust, presenting an ovulation-related gene network with 87 nodes (genes) and 348 edges (interactions between the genes). Related to the network centralities, the network has a betweenness mean value = 102.54; closeness mean = 0.007; and degree mean = 8.0. Moreover, the gene with a higher betweenness was PTPN1. Genes with the higher closeness were SRD5A1 and HSD17B3, and the gene with the lowest closeness was GDF9. Finally, the gene with a higher degree value was UBB; this gene participates in the regulation of TP53 activity pathway.

CONCLUSIONS

This systematic review demonstrated that we cannot use any genetic marker before controlled ovarian stimulation for IVF. Moreover, in silica model is a useful tool for understanding and finding new markers for an IVF individualization.

PROSPERO

CRD42020197185.

Notch signaling pathway in cumulus cells reflecting zygote and embryo quality in polycystic ovary syndrome

PURPOSE

The present study aimed to explore the associations between the expression pattern of molecules in the Notch pathway in the cumulus cells of polycystic ovary syndrome (PCOS) patients and the quality of zygotes and embryos.

METHODS

A total of 200 cumulus complexes surrounding mature oocytes were obtained from 40 patients with and without PCOS undergoing intracytoplasmic sperm injection (ICSI). The expressions of Notch-1, Notch-2, and Notch-3 genes were examined by Reverse Transcription Q-PCR assay. Moreover, immunocytochemistry was performed for the expressions of Jagged-1 and Jagged-2 proteins. The correlations between the Notch receptors and their ligand expressions and the qualities of the zygote and embryo were investigated.

RESULTS

The expression levels of Notch-2, Notch-3, Jagged-1, and Jagged-2 were significantly lower in patients with PCOS than in normal women (p < 0.05), while Notch-1 showed no meaningful difference between the groups. A positive correlation was found between Notch-1 and embryo quality. Furthermore, only Notch-2 and Jagged-2 marginally correlated with zygote quality.

CONCLUSION

The data of the present study indicated that evaluating the molecules in the Notch pathway in PCOS patients' cumulus cells provides a novel approach to predict the zygote and embryo quality. However, further studies on a larger population are needed to validate this finding.

Functional Gene Expression Differentiation of the Notch Signaling Pathway in Female Reproductive Tract Tissues-A Comprehensive Review With Analysis

The Notch pathway involves evolutionarily conserved signaling regulating the development of the female tract organs such as breast, ovary, cervix, and uterine endometrium. A great number of studies revealed Notch aberrancies in association with their carcinogenesis and disease progression, the management of which is still challenging. The present study is a comprehensive review of the available literature on Notch signaling during the normal development and carcinogenesis of the female tract organs. The review has been enriched with our analyses of the TCGA data including breast, cervical, ovarian, and endometrial carcinomas concerning the effects of Notch signaling at two levels: the core components and downstream effectors, hence filling the lack of global overview of Notch-driven carcinogenesis and disease progression. Phenotype heterogeneity regarding Notch signaling was projected in two uniform manifold approximation and projection algorithm dimensions, preceded by the principal component analysis step reducing the data burden. Additionally, overall and disease-free survival analyses were performed with the optimal cutpoint determination by Evaluate Cutpoints software to establish the character of particular Notch components in tumorigenesis. In addition to the review, we demonstrated separate models of the examined cancers of the Notch pathway and its targets, although expression profiles of all normal tissues were much more similar to each other than to its cancerous compartments. Such Notch-driven cancerous differentiation resulted in a case of opposite association with DFS and OS. As a consequence, target genes also show very distinct profiles including genes associated with cell proliferation and differentiation, energy metabolism, or the EMT. In conclusion, the observed Notch associations with the female tract malignancies resulted from differential expression of target genes. This may influence a future analysis to search for new therapeutic targets based on specific Notch pathway profiles.

Functional evidence implicating NOTCH2 missense mutations in primary ovarian insufficiency etiology

Primary ovarian insufficiency (POI) is a frequently occurring disease affecting women under 40 years old. Recently, we have analyzed unrelated POI women via whole exome sequencing (WES) and identified NOTCH2 mutations underlying possible functional effects. The present study involved reanalyzing of WES assays. We used in the KGN granulosa-like cell model, a synthetic gene reporter construct driving luciferase gene expression to assess the functional effects of five NOTCH2 mutations identified in POI patients. We found that NOTCH2-p.Ser1804Leu, p.Ala2316Val, and p.Pro2359Ala mutations had a functional impact on the protein's transcriptional activity. The results have demonstrated for the first time that NOTCH2 mutations contribute to POI etiology. We therefore recommend sequencing NOTCH2's open reading frame in large panels of POI patients to establish an accurate genotype-phenotype correlation. We cannot rule out the fact that patients affected by Alagille syndrome carrying NOTCH2 mutations may suffer ovarian dysfunction.

Utilization of the Bologna criteria: a promise unfulfilled? A review of published and unpublished/ongoing trials

OBJECTIVE

To study the use of the Bologna criteria (BC) for the definition of poor ovarian responders (POR) in clinical practice and research.

DESIGN

Systematic review of published and unpublished/ongoing trials between January 2012 and August 2017 on POR.

SETTING

Not applicable.

PATIENT(S)

Not applicable.

INTERVENTION(S)

The databases were searched using the relevant medical subject headings including all subheadings. The search was limited to humans and English language. The references of the included studies were cross-searched for possibly missed articles. Only clinical trials providing an evidence level ≥ III were included. Case reports, review, letters, and hypothetical articles were excluded.

MAIN OUTCOME MEASURE(S)

Extracted studies were divided into two groups: studies in which the BC were used or not.

RESULT(S)

One hundred nine published clinical studies analyzing a total of 30,540 women and 112 unpublished/ongoing trials were identified. The BC were used to define POR in 56 (51%) of the published and 44 (39%) of the unpublished trials. The use of the BC gradually increased from 29% to 53% from 2012 to 2017. Asian researchers were more likely to use the BC compared with European and North American researchers (65%, 49%, and 23%, respectively). Neither the design of the study nor the impact factor of the publishing journal was correlated with the use of the BC.

CONCLUSION(S)

There is still reluctance to use the BC for the definition of POR, which makes it difficult to combine data from small studies and reach a meaningful conclusion.

The presence of VEGF and Notch2 during preantral-antral follicular transition in infantile rats: Anatomical evidence and its implications

Folliculogenesis is a process that depends on angiogenesis, in which VEGF and Notch signaling pathway members are involved. Although this pathway is present in preantral and antral follicular structures during the second stage of folliculogenesis, this association has not been described. Therefore, this study aimed to identify VEGF and Notch2 in ovary structures of infantile rats after induction of follicular development with a gonadotropin stimulus. In order to explore this possibility we analyzed rat ovary morphology from days 10-25 after birth; subsequently, the transition from preantral follicle to an antral stage was analyzed by the induction of follicular development with equine chorionic gonadotropin (eCG) and VEGF and Notch were identified in the rat ovary by fluorescence. The histological analysis revealed that the ovary of a 10-day-old rat has the highest percentage of preantral follicles and based on this a 10IU eCG dose promoted an increase in the number of antral follicles, as well as a decrease in the number of preantral follicles, related to which there was an increase in ovary weight and size. In addition, a higher concentration of circulating estradiol was observed, proliferation of granulosa cells in both follicle groups was stimulated, and the accumulation of VEGF in granulosa and theca cells and in the antral follicle oocyte was increased (p<0.05), whereas the presence of Notch2 was limited to mural granulosa cells, in granulosa cells that formed the cumulus oophorus and in the oocyte of both groups of follicles. The multiple correspondence analysis allowed us to support an association between VEGF and Notch2 during the transition from preantral to antral follicles in the ovary of an infantile rat.

The role of Notch signaling in the mammalian ovary

The Notch pathway is a contact-dependent, or juxtacrine, signaling system that is conserved in metazoan organisms and is important in many developmental processes. Recent investigations have demonstrated that the Notch pathway is active in both the embryonic and postnatal ovary and plays important roles in events including follicle assembly and growth, meiotic maturation, ovarian vasculogenesis and steroid hormone production. In mice, disruption of the Notch pathway results in ovarian pathologies affecting meiotic spindle assembly, follicle histogenesis, granulosa cell proliferation and survival, corpora luteal function and ovarian neovascularization. These aberrations result in abnormal folliculogenesis and reduced fertility. The knowledge of the cellular interactions facilitated by the Notch pathway is an important area for continuing research, and future studies are expected to enhance our understanding of ovarian function and provide critical insights for improving reproductive health. This review focuses on the expression of Notch pathway components in the ovary, and on the multiple functions of Notch signaling in follicle assembly, maturation and development. We focus on the mouse, where genetic investigations are possible, and relate this information to the human ovary.

Persistence of müllerian duct structures in a genetic male with distal monosomy 10q

Persistent müllerian duct syndrome (PMD) with antimüllerian hormone (AMH) deficiency is usually associated with mutations or deletions of the AMH gene, although many cases have no identified gene association. We report on a genetic male with PMD and AMH deficiency associated with distal monosomy 10q. A term 3,230 g infant was born to a healthy 27-year-old. Fetal ultrasound had shown possible genital ambiguity. Postnatal exam showed a 0.5 cm phallus with basal meatus, normal scrotum with no palpable gonads, no vaginal orifice, and a rectal fistula with an imperforate anus. Voiding cystourethrogram with ultrasound, cystoscopy, and laparoscopy showed normal bladder, urethral orifice, distal vagina, cervix, and bilateral abdominal testis. At 24 hours of life, testosterone was within normal range with low AMH level. Chromosome microarray analysis showed 46, XY, del10(10q25.3q26.13) involving an 8.2 MB interstitial deletion. Whole exome sequencing identified a NOTCH2 variant (1p11.2). AMH sequencing revealed no abnormalities. Following multidisciplinary team and parent discussion, male gender was assigned. Testosterone treatment resulted in penile length of 1.5 cm. Bilateral orchiopexy and posterior sagittal anorectoplasty were performed at 11 months of age; rudimentary müllerian structures were identified. This observation suggests an association of 10qter elements with male differentiation including AMH expression and is similar to a patient with 46, XY, del(10q26.1) in which AMH levels were not reported. Regional candidate genes include FGFR2 (10q26.13). The possible contribution of a NOTCH2 variant cannot be excluded.

Dysregulation of Lysyl Oxidase Expression in Lesions and Endometrium of Women With Endometriosis

Lysyl oxidases (LOXs) are enzymes involved in collagen deposition, extracellular membrane remodeling, and invasive/metastatic potential. Previous studies reveal an association of LOXs and endometriosis. We aimed to identify the mechanisms activated by upregulation of lysyl oxidases (LOX) in endometriotic cells and tissues. We hypothesized that LOX plays a role in endometriosis by promoting invasiveness and epithelial to mesenchymal transition (EMT).

METHODS

The LOX protein expression levels were measured by immunohistochemistry in lesions and endometrium on a tissue microarray (TMA) and in endometrial biopsies from patients and controls during the window of implantation (WOI). Estradiol regulation of LOX expression was determined by quantitative polymerase chain reaction (qPCR). Proliferation, invasion, and migration assays were performed in epithelial (endometrial epithelial cell), endometrial (human endometrial stromal cell), and endometriotic cell lines (ECL and 12Z). Pathway-focused multiplex qPCR was used to determine transcriptome changes due to LOX overexpression.

RESULTS

LOX protein was differentially expressed in ovarian versus peritoneal lesions. During WOI, LOX levels were higher in luminal epithelium of patients with endometriosis-associated infertility compared to controls. Invasive epithelial cell lines expressed higher levels of LOX than noninvasive ones. Transfection of LOX into noninvasive epithelial cells increased their migration in an LOX inhibitor-sensitive manner. Overexpression of LOX did not fully induce EMT but the expression of genes related to fibrosis and extracellular matrix remodeling were dysregulated.

CONCLUSIONS

This study documents that expression of LOX is differentially regulated in endometriotic lesions and endometrium. A role for LOX in mediating proliferation, migration, and invasion of endometrial and endometriotic cells was observed, which may be implicated in the establishment and progression of endometriotic lesions.