The CC-allele of the PvuII polymorphic variant in intron 1 of the α-estrogen receptor gene is significantly more prevalent among infertile women at risk of premature ovarian aging

Estrogen Biosynthesis and Signal Transduction in Ovarian Disease

Estrogen mainly binds to estrogen receptors (ERs) to regulate menstrual cycles and reproduction. The expression of ERalpha (ERα), ERbeta (ERβ), and G-protein-coupled estrogen receptor (GPER) mRNA could be detected in ovary, suggesting that they play an important role in estrogen signal transduction in ovary. And many studies have revealed that abnormal expression of estrogen and its receptors is closely related to ovarian disease or malignant tumors. With the continuous development and research of animal models, tissue-specific roles of both ERα and ERβ have been demonstrated in animals, which enable people to have a deeper understanding of the potential role of ER in regulating female reproductive diseases. Nevertheless, our current understanding of ERs expression and function in ovarian disease is, however, incomplete. To elucidate the biological mechanism behind ERs in the ovary, this review will focus on the role of ERα and ERβ in polycystic ovary syndrome (PCOS), ovarian cancer and premature ovarian failure (POF) and discuss the major challenges of existing therapies to provide a reference for the treatment of estrogen target tissue ovarian diseases.

Genetics of ovarian insufficiency and defects of folliculogenesis

Primary ovarian insufficiency (POI) is determined by exhaustion of follicles in the ovaries, which leads to infertility before the age of 40 years. It is characterized by a strong familial and heterogeneous genetic background. Therefore, we will mainly discuss the genetic basis of POI in this review. We identified 107 genes related to POI etiology in mammals described by several independent groups. Thirty-four of these genes (AARS2, AIRE, ANTXR1, ATM, BMPR1B, CLPP, CYP17A1, CYP19A1, DCAF17, EIF2B, ERAL1, FANCA, FANCC, FMR1, FOXL2, GALT, GNAS, HARS2, HSD17B4, LARS2, LMNA, MGME1, NBN, PMM2, POLG, PREPL, RCBTB1, RECQL2/3/4, STAR, TWNK, and XRCC4/9) have been linked to syndromic POI and are mainly implicated in metabolism function and meiosis/DNA repair. In addition, the majority of genes associated with nonsyndromic POI, widely expanded by high-throughput techniques over the last decade, have been implicated in ovarian development and meiosis/DNA repair pathways (ATG7, ATG9, ANKRD31, BMP8B, BMP15, BMPR1A, BMPR1B, BMPR2, BNC1, BRCA2, CPEB1, C14ORF39, DAZL, DIAPH2, DMC1, ERCC6, FANCL, FANCM, FIGLA, FSHR, GATA4, GDF9, GJA4, HELQ, HSF2BP, HFM1, INSL3, LHCGR, LHX8, MCM8, MCM9, MEIOB, MSH4, MSH5, NANOS3, NOBOX, NOTCH2, NR5A1, NUP107, PGRMC1, POLR3H, PRDM1, PRDM9, PSMC3IP, SOHLH1, SOHLH2, SPIDR, STAG3, SYCE1, TP63, UBR2, WDR62, and XRCC2), whereas a few are related to metabolic functions (EIF4ENIF1, KHDRBS1, MRPS22, POLR2C). Some genes, such as STRA8, FOXO3A, KIT, KITL, WNT4, and FANCE, have been shown to cause ovarian insufficiency in rodents, but mutations in these genes have yet to be elucidated in women affected by POI. Lastly, some genes have been rarely implicated in its etiology (AMH, AMHR2, ERRC2, ESR1, INHA, LMN4, POF1B, POU5F1, REC8, SMC1B). Considering the heterogeneous genetic and familial background of this disorder, we hope that an overview of literature data would reinforce that genetic screening of those patients is worthwhile and helpful for better genetic counseling and patient management.

Deleterious variants in genes regulating mammalian reproduction in Neanderthals, Denisovans and extant humans

STUDY QUESTION

Were Neanderthals and Denisovans (referred here also as extinct hominidae) carrying deleterious variants in genes regulating reproduction?

SUMMARY ANSWER

The majority of extinct hominidae analyzed here, presented a considerable number of deleterious variants per individual in proteins regulating different aspects of reproduction, including gonad and uterine function, and gametogenesis.

WHAT IS KNOWN ALREADY

Neanderthals, Denisovans and extant humans were interfertile and hybridized while occupying geographically overlapping areas in Europe and Asia. This is evidenced by the small archaic genome component (average ∼2%) present in non-African extant humans.

STUDY DESIGN, SIZE, DURATION

The genome of eight extinct hominidae, together with five human genome databases, plus 44 mothers and 48 fathers (fertile controls), were screened to look for deleterious variants in 1734 protein-coding genes regulating reproduction.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ancient DNA from six Neanderthals and two Denisovans dated between ∼82 000 and 43 000 calibrated years was retrieved from the public European Nucleotide Archive. The hominins analyzed include Altai, Vindija 33.15, 33.19, 33.25 and 33.26, El Sidron 1253, Denisova 3 and 11. Their DNA was analyzed using the CLC Genomics Workbench 12, by mapping overlapping paired-end reads (Illumina, FASTQ files) to the human genome assembly GRCh37 (hg19) (Vindija 33.19, 33.25, 33.26, Denisova 3 and Denisova 11) or by analyzing BAM files (Altai, El Sidron 1253 and Vindija 33.15) (human genome reference, GRCh37 (hg19)). Non-synonymous reproductive variants were classified as deleterious or tolerated (PolyPhen-2 and SIFT analyses) and were compared to deleterious variants obtained from extant human genome databases (Genome Aggregation Database (GnomAD), 1000 Genomes, the Haplotype Map (HapMap), Single Nucleotide Polymorphism Database (dbSNPs)) across different populations. A genetic intersection between extant or extinct DNA variants and other genetic disorders was evaluated by annotating the obtained variants with the Clinical Variant (ClinVar) database.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the eight extinct hominidae analyzed, a total of 9650 non-synonymous variants (only coverage ≥20 reads included; frameshift mutations were excluded) in 1734 reproductive protein-coding genes were found, 24% of which were classified as deleterious. The majority (73%) of the deleterious alleles present in extant humans that are shared between extant humans and extinct hominidae were found to be rare (<1%) in extant human populations. A set of 8044 variants were found uniquely in extinct hominidae. At the single-gene level, no extinct individual was found to be homozygous for deleterious variants in genes necessary for gamete recognition and fusion, and no higher chance of embryo-lethality (calculated by Mendelian Genetics) was found upon simulated mating between extant human and extinct hominidae compared to extant human-extant human. However, three of the eight extinct hominidae were found to be homozygous for 48-69 deleterious variants in 55 genes controlling ovarian and uterine functions, or oogenesis (AKAP1, BUB1B, CCDC141, CDC73, DUSP6, ESR1, ESR2, PATL2, PSMC3IP, SEMA3A, WT1 and WNT4). Moreover, we report the distribution of nine Neanderthal variants in genes associated with a human fertility phenotype found in extant human populations, one of which has been associated with polycystic ovarian syndrome and primary congenital glaucoma.

LIMITATIONS, REASONS FOR CAUTION

While analyzing archaic DNA, stringent filtering criteria were adopted to screen for deleterious variants in Neanderthals and Denisovans, which could result in missing a number of variants. Such restraints preserve the potential for detection of additional deleterious variants in reproductive proteins in extinct hominidae.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides a comprehensive overview of putatively deleterious variants in extant human populations and extinct individuals occurring in 1734 protein-coding genes controlling reproduction and provides the fundaments for future functional studies of extinct variants in human reproduction.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Department of Biological Science and by the Office of Research and Sponsored Programs at the University of Tulsa (Faculty Research Grant and Faculty Research Summer Fellowship) to M.A. and the University of Tulsa, Tulsa Undergraduate Research Challenge (TURC) program to E.L.; no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Network pharmacology-based screening of the active ingredients and mechanisms of Huangqi against aging

ABSTRACT

Studies have shown that Huangqi (HQ) has anti-aging efficacy. However, its active ingredients and mechanisms for anti-aging are still unclear. In this study, we will systematically screen the active ingredients of HQ and explore the possible mechanism of HQ in prevention from aging through network pharmacology technology.The main active ingredients of HQ were obtained from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). The possible targets were predicted by TCMSP. The related targets for aging were obtained from GeneCards (The Human Gene Database) and Online Mendelian Inheritance in Man (OMIM) database. The common targets of HQ and aging were obtained using R 3.6.3 software. The protein-protein interaction (PPI) network and the ingredient-target-disease network were constructed using Cytoscape 3.7.2 software for visualization. In addition, the Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation of potential targets were performed using R 3.6.3 software.Based on the screening conditions, 16 active ingredients and 28 drug targets were obtained. The PPI network contained 29 proteins, including PTGS2, AR, NOS2, and so on. GO functional enrichment analysis obtained 40 GO items (P < .05). KEGG pathway enrichment analysis obtained 110 aging related pathways (P < .05), including hypoxia inducible factor 1 signaling pathway, PI3K-Akt signaling pathway, AGE-RAGE signaling pathway in diabetic complication, among others.Sixteen effective ingredients of HQ and 28 targets against aging were identified through network pharmacology. Multiple pathways were involved in the effect of HQ on preventing aging.

Fertility Enhancement but Premature Ovarian Failure in esr1-Deficient Female Zebrafish

It is well established that estrogens regulate female reproduction through estrogen receptors (ERs) in the ovary. However, the precise physiological role of estrogen/ER signaling in reproduction processes remains poorly defined in zebrafish. In this study, we successfully generated an ERα (esr1) mutant line in zebrafish via transcription activator-like effectors nucleases (TALENs). It was found in the mutant females that the fertility was enhanced and the ovarian histology was normal at 90 days post-fertilization (dpf). However, the number of fertile females decreased with age. By 180 dpf, esr1 mutant females were infertile with degenerated ovaries, while the age-matched wild-type females were still fertile. Additionally, few large vitellogenic granules can be found in full grown (FG) follicles at 90 dpf and the expression of vtg genes were down-regulated at both 90 and 180 dpf in esr1 mutant zebrafish. Moreover, steroidogenesis pathway and mTOR signaling pathway were over-activated at 90 dpf, but declined prematurely in esr1 mutant zebrafish by 180 dpf. Collectively, the present study provides evidence that esr1 is fundamental for ovarian maintenance in zebrafish.

Genetics of the ovarian reserve

Primordial follicles or non-growing follicles (NGFs) are the functional unit of reproduction, each comprising a single germ cell surrounded by supporting somatic cells. NGFs constitute the ovarian reserve (OR), prerequisite for germ cell ovulation and the continuation of the species. The dynamics of the reserve is determined by the number of NGFs formed and their complex subsequent fates. During the reproductive lifespan, the OR progressively diminishes due to follicle atresia as well as recruitment, maturation, and ovulation. The depletion of the OR is the major determining driver of menopause, which ensues when the number of primordial follicles falls below a threshold of ∼1,000. Therefore, genes and processes involved in follicle dynamics are particularly important to understand the process of menopause, both in the typical reproductive lifespan and in conditions like primary ovarian insufficiency, defined as menopause before age 40. Genes and their variants that affect the timing of menopause thereby provide candidates for diagnosis of and intervention in problems of reproductive lifespan. We review the current knowledge of processes and genes involved in the development of the OR and in the dynamics of ovarian follicles.

The genetics of premature ovarian failure: current perspectives

Premature ovarian failure (POF) is a common cause of infertility in women, characterized by amenorrhea, hypoestrogenism, and elevated gonadotropin levels in women under the age of 40. Many genes have been identified over the past few years that contribute to the development of POF. However, few genes have been identified that can explain a substantial proportion of cases of POF. The unbiased approaches of genome-wide association studies and next-generation sequencing technologies have identified several novel genes implicated in POF. As only a small proportion of genes influencing idiopathic POF have been identified thus far, it remains to be determined how many genes and molecular pathways may influence idiopathic POF development. However, owing to POF’s diverse etiology and genetic heterogeneity, we expect to see the contribution of several new and novel molecular pathways that will greatly enhance our understanding of the regulation of ovarian function. Future genetic studies in large cohorts of well-defined, unrelated, idiopathic POF patients will provide a great opportunity to identify the missing heritability of idiopathic POF. The identification of several causative genes may allow for early detection and would provide better opportunity for early intervention, and furthermore, the identification of specific gene defects will help direct potential targets for future treatment.

Transcription factor SOHLH1 potentially associated with primary ovarian insufficiency

OBJECTIVE

To investigate whether gene variants of SOHLH1 exist in Chinese and Serbian patients with primary ovarian insufficiency (POI).

DESIGN

Case-control genetic study.

SETTING

University hospitals.

PATIENT(S)

A total of 364 Han Chinese and 197 Serbian women with nonsyndromic POI and ethnically matched controls.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

SOHLH1 gene sequencing.

RESULT(S)

We found 10 novel heterozygous variants in our cohorts of 561 women with POI but none in the 600 ethnically matched controls. Statistical and bioinformatic analyses indicated that three of the eight variants in Chinese POI cases are potentially disease causing. They comprise two missense variants (p.Ser317Phe and p.Glu376Lys) that might each change activity of the SOHLH1 protein as a transcription factor and one variant (c.*118C>T) located in the 3' untranslated region of the SOHLH1 gene, which might generate a new binding site for the microRNA hsa-miR-888-5p. Of the two variants in the Serbian POI cases, both were synonymous, and no missense variant was identified. The allele frequencies of some known single-nucleotide polymorphisms were statistically significantly different between patients and controls in both the Chinese and Serbian groups.

CONCLUSION(S)

Our results suggest that SOHLH1 may be regarded as a new candidate gene for POI.

ESR1 rs9340799 is associated with endometriosis-related infertility and in vitro fertilization failure

Estrogen receptor alpha has a central role in human fertility by regulating estrogen action in all human reproductive tissues. Leukemia inhibitory factor (LIF) expression, a cytokine critical for blastocyst implantation, is mediated by estrogen signaling, so we hypothesized that ESR1 gene polymorphisms might be candidate risk markers for endometriosis-related infertility and in vitro fertilization (IVF) failure. We included 98 infertile women with endometriosis, 115 infertile women with at least one IVF failure and also 134 fertile women as controls. TaqMan SNP assays were used for genotyping LIF (rs929271), MDM2 (rs2279744), MDM4 (rs1563828), USP7 (rs1529916), and ESR1 (rs9340799 and rs2234693) polymorphisms. The SNP ESR1 rs9340799 was associated with endometriosis-related infertility (P < 0.001) and also with IVF failure (P = 0.018). After controlling for age, infertile women with ESR1 rs9340799 GG genotype presented 4-fold increased risk of endometriosis (OR 4.67, 95% CI 1.84–11.83, P = 0.001) and 3-fold increased risk of IVF failure (OR 3.33, 95% CI 1.38–8.03, P = 0.007). Our results demonstrate an association between ESR1 rs9340799 polymorphism and infertile women with endometriosis and also with women who were submitted to IVF procedures and had no blastocyst implantation.

Genetic associations with diminished ovarian reserve: a systematic review of the literature

PURPOSE

Diminished ovarian reserve (DOR) affects 10 % of women seeking fertility treatment. Although it is much more prevalent than premature ovarian failure, less is known about its etiology. The purpose of this article is to review the possible genetic causes of, and associations with, pathologic DOR.

METHODS

A systematic review was conducted using PubMed from 1966 through November 2013.

RESULTS

Twenty-one articles identified genes associated with DOR: one gene mutation (FMR1), three polymorphisms (GDF9, FSHR, and ESR1), and seven genes differentially expressed between women with DOR and controls (AMH, LHCGR, IGF1, IGF2, IGF1R, IGF2R and GREM1). Six candidate genes were discovered in mice, including Foxl2, Gdf9, Bmp15, Aire, Wnt4, and Gpr3. Two case reports of chromosomal translocations were also identified.

CONCLUSIONS

While the etiology of pathologic DOR is likely multifactorial, it is possible that many cases attributed to an idiopathic cause may have a genetic component. Larger studies are needed to expose the impact gene mutations, polymorphisms, and epigenetics have on pathologic DOR.

COMT polymorphism influences decrease of ovarian follicles and emerges as a predictive factor for premature ovarian insufficiency

Background

Estrogens are important factors in the female reproductive functions and are processed by a number of enzymes along their metabolic pathway. The COMT gene constitutes a crucial element in estrogen metabolism and is assumed to be involved in the development of Premature Ovarian Insufficiency (POI). This study aimed to determine whether the presence of the COMT Val/Met polymorphism (rs4680) is associated to the risk of developing POI.

Findings

In this case–control study, we evaluated 96 infertile women with POI and 120 fertile women as controls, after obtaining a detailed history of the disease and follicle-stimulating hormone measurements, besides karyotype determination and fragile-X premutation syndrome investigation. COMT (Val/Met) genotypes were identified by real time PCR (genotyping TaqMan assay), and the results were statistically analyzed. A statistically significant difference was found in the distribution of COMT genotypes (p = 0.003) and alleles (p = 0.015) between the POI patients and the control group.

Conclusion

We were able to demonstrate a strong association between the COMT Val/Met polymorphism and the risk of premature ovarian insufficiency in the Brazilian women evaluated. However, further studies in larger populations are necessary to confirm these findings.

Association study of estrogen receptor alpha gene polymorphisms with spontaneous abortion: is this a possible reason for unexplained spontaneous abortion?

Estrogen plays a crucial role in fetal and placental development through estrogen receptors. Association of estrogen receptor alpha gene (ESR1) polymorphisms with spontaneous abortion has been shown in some studies. Our main goal was to study the potential association of spontaneous abortion with the ESR1 gene variations (PvuII and XbaI) in fetal tissue. Totally, 161 samples were recruited including 80 samples of formalin-fixed paraffin-embedded fetal tissue from spontaneous abortion and 81 samples of normal term placental tissue. The restriction fragment length polymorphism (RFLP) method was performed for genotyping the rs2234693 (A/G XbaI) and rs9340799 (T/C PvuII) single nucleotide polymorphisms located in intron 1 of ESR1. The results have been confirmed by DNA sequencing analysis. The different genotypes distribution was detected in two study groups. Haplotype analysis indicated that ppxx is protective genotype against spontaneous abortion (P = 0.01). In conclusion, the potential role of ESR1 genetic variation in spontaneous abortion might be valuable in high-risk subjects, and that needs to be confirmed with future studies.

Similar prevalence of expanded CGG repeat lengths in the fragile X mental retardation I gene among infertile women and among women with proven fertility: a prospective study

PURPOSE

We sought to determine the usefulness of fragile X mental retardation 1 (FMR1) carrier testing among young infertile women with or without signs of ovarian insufficiency as compared with fertile women.

METHODS

Three cohorts of women were recruited to determine the cytosine-guanine-guanine (CGG) repeats trinucleotide repeat length in the 5'-untranslated region of the FMR1 gene in lymphocyte DNA. A total of 199 fertile women, who were reported to have conceived within 3 months, were recruited together with 372 infertile women with ongoing menstrual cycles and 48 infertile women with primary ovarian insufficiency. The various ranges of FMR1 CGG repeat lengths among infertile women were compared with those of fertile controls. In infertile women with ongoing menstrual cycles, the serum concentrations of follicle-stimulating hormone, anti-Muellerian hormone, and inhibin B were measured during the early follicular phase.

RESULTS

None of the three categories of FMR1 CGG repeat length expansions (premutation, intermediate range, and high normal range) were more prevalent among infertile women than among fertile women. The CGG repeat length was not correlated with any of the ovarian reserve parameters.

CONCLUSION

In comparison with a generalized preconception screening strategy, infertility as a criterion, even together with reduced ovarian reserve, is not suitable for identifying a higher proportion of women with expanded FMR1 CGG repeat length.

Genomic markers of ovarian reserve

Ovarian reserve and its utilization, over a reproductive life span, are determined by genetic, epigenetic, and environmental factors. The establishment of the primordial follicle pool and the rate of primordial follicle activation have been under intense study to determine genetic factors that affect reproductive lifespan. Much has been learned from transgenic animal models about the developmental origins of the primordial follicle pool and mechanisms that lead to primordial follicle activation, folliculogenesis, and the maturation of a single oocyte with each menstrual cycle. Recent genome-wide association studies on the age of human menopause have identified approximately 20 loci, and shown the importance of factors involved in double-strand break repair and immunology. Studies to date from animal models and humans show that many genes determine ovarian aging, and that there is no single dominant allele yet responsible for depletion of the ovarian reserve. Personalized genomic approaches will need to take into account the high degree of genetic heterogeneity, family pedigree, and functional data of the genes critical at various stages of ovarian development to predict women's reproductive life span.

Do estrogen receptor alpha polymorphisms have any impact on the outcome in an ART program?

PURPOSE

To investigate two of the most studied estrogen receptor alpha polymorphisms (PvuII and XbaI) in combination, in order to evaluate their impact on an ART program outcome.

METHODS

203 normally ovulating women who underwent IVF or ICSI treatment were genotyped for PvuII and XbaI polymorphisms in ESR1 intron 1 using Real-Time PCR. The relationship between the presence of polymorphic alleles and the ovulation induction parameters and outcome was examined.

RESULTS

Women were grouped according to the number of polymorphic alleles they carried in two groups (0-2 versus 3-4 polymorphic alleles). The presence of 3 or more polymorphic alleles was associated with significantly lower E2 levels on the day of hCG administration and a significantly lower rate of good quality embryos.

CONCLUSION

There is an association between ESR1 polymorphisms and some ART parameters such as the level of E2 on the day of hCG administration and the quality of the embryos. These results underline the importance of ESR1 as a candidate gene for the prediction of ovarian response to IVF/ICSI protocols. Future research work concerning several more genes is necessary for a better evaluation of patients before entering an IVF/ICSI program.

Risk of premature ovarian failure is associated to the PvuII polymorphism at estrogen receptor gene ESR1

PURPOSE

Estrogen plays an important role in the human reproductive system and it action is mediated mainly by two specific receptors: α (ERα) and β (ERβ). There were described polymorphic variants in ESR1 and ESR2 genes and studies showed controversial results regarding their association with premature ovarian failure. We aimed to determine the prevalence of ESR1 and ESR2 polymorphisms in Brazilian patients and controls. After associate the polymorphisms with premature ovarian failure (POF).

METHODS

Genetic association study was performed with 70 women with POF and 73 normally menopaused controls. Detection of ESR1 (PvuII/and XbaI) and ESR2 (AluI and RsaI) gene polymorphisms were performed using TaqMan PCR. The single-nucleotide polymorphism (SNPs) and haplotype effects were analyzed by multivariate logistic regression and haplotype analysis and a p-value < 0.05 was considered significant.

RESULTS

Individual SNP analysis revealed that PvuII polymorphism was statistically associated with POF (p = 0.034) under a recessive model. Regarding XbaI, AluI and RsaI SNPs, no statistical difference was observed between POF group and controls (p = 0.575, p = 0.258 and p = 0.483, respectively). Combined genotypes of ESR1 and ESR2 polymorphisms did not identify a risk haplotype associated with POF.

CONCLUSION

In Brazilian population evaluated results have demonstrated that the genetic variation in ESR1 gene (PvuII polymorphism) is associated to POF risk.