A human homologue of the Drosophila melanogaster diaphanous gene is disrupted in a patient with premature ovarian failure: evidence for conserved function in oogenesis and implications for human sterility

Searching for the 'X' factor: investigating the genetics of primary ovarian insufficiency

Primary ovarian insufficiency (POI) is the cessation of ovarian function before the age of 40. The causes of POI are heterogeneous, but substantial evidence exists to support a genetic basis of POI, particularly in the critical involvement of genes on the X chromosome. Recent studies have revealed novel candidate genes through the identification of copy number variations associated with POI. This review summarizes the genes located on the X chromosome with variants shown to be associated with POI in humans and/or in mice. Additionally, we present evidence to support the potential involvement of these candidate genes in the etiology of POI. We conducted a literature search in PubMed to identify case studies and screenings for the genetic causes of POI. We then performed systematic searches for the proposed candidate genes to investigate their potential reproductive roles. Of the X-linked candidate genes investigated, 10 were found to have variants associated with cases of POI in humans. An additional 10 genes were found to play a supportive role in POI. Other genes were not implicated in any cases of POI but were associated with various roles in reproduction. In the majority of cases where variants were identified through whole-exome sequencing, rather than targeted screening of candidate genes, more than one genetic variant was identified. Overall, this review supports past findings that the X chromosome plays a critical role in ovarian function, as demonstrated by a link between POI and various disruptions to genes on the X chromosome. Current genetic screening for POI, which includes only FMR1, is inadequate to capture the majority of cases with a genetic origin. An expanded genetic testing may improve health outcomes for individuals with POI as it could lead to better early interventions and education about these health risks.

Diaph1 knockout inhibits mouse primordial germ cell proliferation and affects gonadal development

BACKGROUND

Exploring the molecular mechanisms of primordial germ cell (PGC) migration and the involvement of gonadal somatic cells in gonad development is valuable for comprehending the origins and potential treatments of reproductive-related diseases.

METHODS

Diaphanous related formin 1 (Diaph1, also known as mDia1) was screened by analyzing publicly available datasets (ATAC-seq, DNase-seq, and RNA-seq). Subsequently, the CRISPR-Cas9 technology was used to construct Diaph1 knockout mice to investigate the role of Diaph1 in gonad development.

RESULTS

Based on data from public databases, a differentially expressed gene Diaph1, was identified in the migration of mouse PGC. Additionally, the number of PGCs was significantly reduced in Diaph1 knockout mice compared to wild type mice, and the expression levels of genes related to proliferation (Dicer1, Mcm9), adhesion (E-cadherin, Cdh1), and migration (Cxcr4, Hmgcr, Dazl) were significantly decreased. Diaph1 knockout also inhibited Leydig cell proliferation and induced apoptosis in the testis, as well as granulosa cell apoptosis in the ovary. Moreover, the sperm count in the epididymal region and the count of ovarian follicles were significantly reduced in Diaph1 knockout mice, resulting in decreased fertility, concomitant with lowered levels of serum testosterone and estradiol. Further research found that in Diaph1 knockout mice, the key enzymes involved in testosterone synthesis (CYP11A1, 3β-HSD) were decreased in Leydig cells, and the estradiol-associated factor (FSH receptor, AMH) in granulosa cells were also downregulated.

CONCLUSIONS

Overall, our findings indicate that the knockout of Diaph1 can disrupt the expression of factors that regulate sex hormone production, leading to impaired secretion of sex hormones, ultimately resulting in damage to reproductive function. These results provide a new perspective on the molecular mechanisms underlying PGC migration and gonadal development, and offer valuable insights for further research on the causes, diagnosis, and treatment of related diseases.

Germ fate determinants protect germ precursor cell division by reducing septin and anillin levels at the cell division plane

Animal cell cytokinesis, or the physical division of one cell into two, is thought to be driven by constriction of an actomyosin contractile ring at the division plane. The mechanisms underlying cell type-specific differences in cytokinesis remain unknown. Germ cells are totipotent cells that pass genetic information to the next generation. Previously, using formincyk-1(ts) mutant Caenorhabditis elegans 4-cell embryos, we found that the P2 germ precursor cell is protected from cytokinesis failure and can divide with greatly reduced F-actin levels at the cell division plane. Here, we identified two canonical germ fate determinants required for P2-specific cytokinetic protection: PIE-1 and POS-1. Neither has been implicated previously in cytokinesis. These germ fate determinants protect P2 cytokinesis by reducing the accumulation of septinUNC-59 and anillinANI-1 at the division plane, which here act as negative regulators of cytokinesis. These findings may provide insight into the regulation of cytokinesis in other cell types, especially in stem cells with high potency.

DIAPH3 predicts survival of patients with MGMT-methylated glioblastoma

Background

Glioblastoma is one of the most aggressive primary brain tumors, with a poor outcome despite multimodal treatment. Methylation of the MGMT promoter, which predicts the response to temozolomide, is a well-established prognostic marker for glioblastoma. However, a difference in survival can still be detected within the MGMT methylated group, with some patients exhibiting a shorter survival than others, emphasizing the need for additional predictive factors.

Methods

We analyzed DIAPH3 expression in glioblastoma samples from the cancer genome atlas (TCGA). We also retrospectively analyzed one hundred seventeen histological glioblastomas from patients operated on at Saint-Luc University Hospital between May 2013 and August 2019. We analyzed the DIAPH3 expression, explored the relationship between mRNA levels and Patient's survival after the surgical resection. Finally, we assessed the methylation pattern of the DIAPH3 promoter using a targeted deep bisulfite sequencing approach.

Results

We found that 36% and 1% of the TCGA glioblastoma samples exhibit copy number alterations and mutations in DIAPH3, respectively. We scrutinized the expression of DIAPH3 at single cell level and detected an overlap with MKI67 expression in glioblastoma proliferating cells, including neural progenitor-like, oligodendrocyte progenitor-like and astrocyte-like states. We quantitatively analyzed DIAPH3 expression in our cohort and uncovered a positive correlation between DIAPH3 mRNA level and patient's survival. The effect of DIAPH3 was prominent in MGMT-methylated glioblastoma. Finally, we report that the expression of DIAPH3 is at least partially regulated by the methylation of three CpG sites in the promoter region.

Conclusion

We propose that combining the DIAPH3 expression with MGMT methylation could offer a better prediction of survival and more adapted postsurgical treatment for patients with MGMT-methylated glioblastoma.

Germ fate determinants protect germ precursor cell division by restricting septin and anillin levels at the division plane

Animal cell cytokinesis, or the physical division of one cell into two, is thought to be driven by constriction of an actomyosin contractile ring at the division plane. The mechanisms underlying cell type-specific differences in cytokinesis remain unknown. Germ cells are totipotent cells that pass genetic information to the next generation. Previously, using formin cyk-1 (ts) mutant C. elegans embryos, we found that the P2 germ precursor cell is protected from cytokinesis failure and can divide without detectable F-actin at the division plane. Here, we identified two canonical germ fate determinants required for P2-specific cytokinetic protection: PIE-1 and POS-1. Neither has been implicated previously in cytokinesis. These germ fate determinants protect P2 cytokinesis by reducing the accumulation of septin UNC-59 and anillin ANI-1 at the division plane, which here act as negative regulators of cytokinesis. These findings may provide insight into cytokinetic regulation in other cell types, especially in stem cells with high potency.

Premature ovarian insufficiency is associated with global alterations in the regulatory landscape and gene expression in balanced X-autosome translocations

BACKGROUND

Patients with balanced X-autosome translocations and premature ovarian insufficiency (POI) constitute an interesting paradigm to study the effect of chromosome repositioning. Their breakpoints are clustered within cytobands Xq13-Xq21, 80% of them in Xq21, and usually, no gene disruption can be associated with POI phenotype. As deletions within Xq21 do not cause POI, and since different breakpoints and translocations with different autosomes lead to this same gonadal phenotype, a "position effect" is hypothesized as a possible mechanism underlying POI pathogenesis.

OBJECTIVE AND METHODS

To study the effect of the balanced X-autosome translocations that result in POI, we fine-mapped the breakpoints in six patients with POI and balanced X-autosome translocations and addressed gene expression and chromatin accessibility changes in four of them.

RESULTS

We observed differential expression in 85 coding genes, associated with protein regulation, multicellular regulation, integrin signaling, and immune response pathways, and 120 differential peaks for the three interrogated histone marks, most of which were mapped in high-activity chromatin state regions. The integrative analysis between transcriptome and chromatin data pointed to 12 peaks mapped less than 2 Mb from 11 differentially expressed genes in genomic regions not related to the patients' chromosomal rearrangement, suggesting that translocations have broad effects on the chromatin structure.

CONCLUSION

Since a wide impact on gene regulation was observed in patients, our results observed in this study support the hypothesis of position effect as a pathogenic mechanism for premature ovarian insufficiency associated with X-autosome translocations. This work emphasizes the relevance of chromatin changes in structural variation, since it advances our knowledge of the impact of perturbations in the regulatory landscape within interphase nuclei, resulting in the position effect pathogenicity.

In-depth genetic and molecular characterization of diaphanous related formin 2 (DIAPH2) and its role in the inner ear

Diaphanous related formins are regulatory cytoskeletal protein involved in actin elongation and microtubule stabilization. In humans, defects in two of the three diaphanous genes (DIAPH1 and DIAPH3) have been associated with different types of hearing loss. Here, we investigate the role of the third member of the family, DIAPH2, in nonsyndromic hearing loss, prompted by the identification, by exome sequencing, of a predicted pathogenic missense variant in DIAPH2. This variant occurs at a conserved site and segregated with nonsyndromic X-linked hearing loss in an Italian family. Our immunohistochemical studies indicated that the mouse ortholog protein Diaph2 is expressed during development in the cochlea, specifically in the actin-rich stereocilia of the sensory outer hair cells. In-vitro studies showed a functional impairment of the mutant DIAPH2 protein upon RhoA-dependent activation. Finally, Diaph2 knock-out and knock-in mice were generated by CRISPR/Cas9 technology and auditory brainstem response measurements performed at 4, 8 and 14 weeks. However, no hearing impairment was detected. Our findings indicate that DIAPH2 may play a role in the inner ear; further studies are however needed to clarify the contribution of DIAPH2 to deafness.

Chromosomal abnormalities detected by karyotyping among patients with secondary amenorrhea: a retrospective study

BACKGROUND

Chromosomal abnormalities (CAs) have been described in patients with secondary amenorrhea (SA). However, studies on this association are scarce.

OBJECTIVES

To evaluate the frequency and types of CAs detected by karyotyping in patients with SA.

DESIGN AND SETTING

This retrospective study was performed in a reference clinical genetic service in South Brazil.

METHODS

Data were obtained from the medical records of patients with SA who were evaluated between 1975 and 2022. Fisher's bicaudate exact test and Student's t-test were used, and P < 0.05 was considered significant.

RESULTS

Among 43 patients with SA, 14 (32.6%) had CAs, namely del (Xq) (n = 3), 45,X (n = 2), 46,X,r(X)/45,X (n = 2), 46,XX/45,X (n = 1), 46,X,i(q10)/45,X (n = 1), 47,XXX (n = 1), 46,XX/47,XXX (n = 1), 46,XX/47,XX,+mar (n = 1), 45,XX,trob(13;14)(q10;q10)/46,XXX,trob(13;14)(q10;q10) (n = 1), and 46,XX,t(2;21)(q23;q11.2) (n = 1). Additional findings were observed mostly among patients with CA compared with those without CA (P = 0.0021). No difference in the mean age was observed between the patients with SA with or without CAs (P = 0.268025).

CONCLUSIONS

CAs are common among patients with SA, especially those with short stature and additional findings. They are predominantly structural, involve the X chromosome in a mosaic, and are compatible with the Turner syndrome. Patients with SA, even if isolated, may have CAs, particularly del (Xq) and triple X.

Ovarian dysfunction in women with Turner syndrome

Ovarian dysfunction is one of the most common features of women with Turner syndrome. In these women, oocyte apoptosis is markedly accelerated from the early stage of fetal life. Reduction in the number of germ cells disturbs primordial follicle development and thereby leads to the formation of streak gonads. There are three possible causes of accelerated germ cell loss in 45,X ovaries. First, chromosomal pairing failure due to X chromosomal aneuploidy is believed to induce meiotic arrest. Indeed, it has been suggested that the dosage of the X chromosome is more critical for the survival of the oocytes than for other cells in the ovary. Second, impaired coupling between oocytes and granulosa cells may also contribute to germ cell apoptosis. Previous studies have shown that 45,X ovaries may tend to lose tight junctions which are essential for intercellular interactions. Lastly, ovarian dysfunction in women with Turner syndrome is partly attributable to the reduced dosage of several genes on the X chromosome. Specifically, BMP15, PGRMC1, and some other genes on the X chromosome have been implicated in ovarian function. Further studies on the mechanisms of ovarian dysfunction are necessary to improve the reproductive outcomes of women with Turner syndrome.

Ovarian Reserve Disorders, Can We Prevent Them? A Review

The ovarian reserve is finite and begins declining from its peak at mid-gestation until only residual follicles remain as women approach menopause. Reduced ovarian reserve, or its extreme form, premature ovarian insufficiency, stems from multiple factors, including developmental, genetic, environmental exposures, autoimmune disease, or medical/surgical treatment. In many cases, the cause remains unknown and resulting infertility is not ultimately addressed by assisted reproductive technologies. Deciphering the mechanisms that underlie disorders of ovarian reserve could improve the outcomes for patients struggling with infertility, but these disorders are diverse and can be categorized in multiple ways. In this review, we will explore the topic from a perspective that emphasizes the prevention or mitigation of ovarian damage. The most desirable mode of fertoprotection is primary prevention (intervening before ablative influence occurs), as identifying toxic influences and deciphering the mechanisms by which they exert their effect can reduce or eliminate exposure and damage. Secondary prevention in the form of screening is not recommended broadly. Nevertheless, in some instances where a known genetic background exists in discrete families, screening is advised. As part of prenatal care, screening panels include some genetic diseases that can lead to infertility or subfertility. In these patients, early diagnosis could enable fertility preservation or changes in family-building plans. Finally, Tertiary Prevention (managing disease post-diagnosis) is critical. Reduced ovarian reserve has a major influence on physiology beyond fertility, including delayed/absent puberty or premature menopause. In these instances, proper diagnosis and medical therapy can reduce adverse effects. Here, we elaborate on these modes of prevention as well as proposed mechanisms that underlie ovarian reserve disorders.

Hypoxia-induced epigenetic transgenerational miRNAs dysregulation involved in reproductive impairment of ovary

Hypoxia is a potent endocrine disruptor that is posing serious problems to the fish reproductive systems. Our previous studies reported that hypoxia could cause a transgenerational impairment of ovarian development and interfere hatching success in F2 offspring of marine medaka fish (Oryzias melastigma) through epigenetic regulation. As part of the epigenetic regulation, we investigated the involvement of microRNAs (miRNAs) in hypoxia-induced transgenerational reproductive impairments. In the present study, we used comparative small RNA sequencing to reveal that hypoxia caused miRNA dysregulation in ovaries of F0 hypoxia group and F2 transgenerational group. We found 4 common dysregulated miRNA in the F0 and F2 generations. Furthermore, integrated miRNA-mRNA analysis, followed by gene ontology enrichment analysis on the hypoxia-dysregulated miRNA-target genes further highlighted the importance of these dysregulated miRNAs in biological processes related to reproduction. More importantly, we identified 3 miRNA-mRNA pairs (novel miRNA-525-DIAPH2, novel miRNA-525-MYOCD, and novel miRNA-525-RAI14) that might play epigenetic roles in hypoxia-induced reproductive impairment. For the first time, our findings suggested the involvement of miRNA in hypoxia-induced reproductive impairments may be inherited via a transgenerational manner.

Comparison of the somatic TADs and lampbrush chromomere-loop complexes in transcriptionally active prophase I oocytes

In diplotene oocyte nuclei of all vertebrate species, except mammals, chromosomes lack interchromosomal contacts and chromatin is linearly compartmentalized into distinct chromomere-loop complexes forming lampbrush chromosomes. However, the mechanisms underlying the formation of chromomere-loop complexes remain unexplored. Here we aimed to compare somatic topologically associating domains (TADs), recently identified in chicken embryonic fibroblasts, with chromomere-loop complexes in lampbrush meiotic chromosomes. By measuring 3D-distances and colocalization between linear equidistantly located genomic loci, positioned within one TAD or separated by a TAD border, we confirmed the presence of predicted TADs in chicken embryonic fibroblast nuclei. Using three-colored FISH with BAC probes, we mapped equidistant genomic regions included in several sequential somatic TADs on isolated chicken lampbrush chromosomes. Eight genomic regions, each comprising two or three somatic TADs, were mapped to non-overlapping neighboring lampbrush chromatin domains - lateral loops, chromomeres, or chromomere-loop complexes. Genomic loci from the neighboring somatic TADs could localize in one lampbrush chromomere-loop complex, while genomic loci belonging to the same somatic TAD could be localized in neighboring lampbrush chromomere-loop domains. In addition, FISH-mapping of BAC probes to the nascent transcripts on the lateral loops indicates transcription of at least 17 protein-coding genes and 2 non-coding RNA genes during the lampbrush stage of chicken oogenesis, including genes involved in oocyte maturation and early embryo development.

Role of Cytoskeletal Diaphanous-Related Formins in Hearing Loss

Hearing relies on the proper functioning of auditory hair cells and on actin-based cytoskeletal structures. Diaphanous-related formins (DRFs) are evolutionarily conserved cytoskeletal proteins that regulate the nucleation of linear unbranched actin filaments. They play key roles during metazoan development, and they seem particularly pivotal for the correct physiology of the reproductive and auditory systems. Indeed, in Drosophila melanogaster, a single diaphanous (dia) gene is present, and mutants show sterility and impaired response to sound. Vertebrates, instead, have three orthologs of the diaphanous gene: DIAPH1, DIAPH2, and DIAPH3. In humans, defects in DIAPH1 and DIAPH3 have been associated with different types of hearing loss. In particular, heterozygous mutations in DIAPH1 are responsible for autosomal dominant deafness with or without thrombocytopenia (DFNA1, MIM #124900), whereas regulatory mutations inducing the overexpression of DIAPH3 cause autosomal dominant auditory neuropathy 1 (AUNA1, MIM #609129). Here, we provide an overview of the expression and function of DRFs in normal hearing and deafness.

Whole-exome sequencing reveals new potential genes and variants in patients with premature ovarian insufficiency

PURPOSE

Premature ovarian insufficiency (POI) is a heterogeneous disorder characterized by the cessation of menstrual cycles before the age of 40 years due to the depletion or dysfunction of the ovarian follicles. POI is a highly heterogeneous disease in terms of etiology. The aim of this study is to reveal the genetic etiology in POI patients.

METHODS

A total of 35 patients (mean age: 27.2 years) from 28 different families diagnosed with POI were included in the study. Karyotype, FMR1 premutation analysis, single nucleotide polymorphism (SNP) array, and whole-exome sequencing (WES) were conducted to determine the genetic etiology of patients.

RESULTS

A total of 35 patients with POI were first evaluated by karyotype analysis, and chromosomal anomaly was detected in three (8.5%) and FMR1 premutation was detected in six patients (17%) from two different families. A total of 29 patients without FMR1 premutation were included in the SNP array analysis, and one patient had a 337-kb deletion in the chromosome 6q26 region including PARK2 gene, which was thought to be associated with POI. Twenty-nine cases included in SNP array analysis were evaluated simultaneously with WES analysis, and genetic variant was detected in 55.1% (16/29).

CONCLUSION

In the present study, rare novel variants were identified in genes known to be associated with POI, which contribute to the mutation spectrum. The effects of detected novel genes and variations on different pathways such as gonadal development, meiosis and DNA repair, or metabolism need to be investigated by experimental studies. Molecular etiology allows accurate genetic counseling to the patient and family as well as fertility planning.

Whole exome sequencing in a cohort of familial premature ovarian insufficiency cases reveals a broad array of pathogenic or likely pathogenic variants in 50% of families

OBJECTIVE

To study the diagnostic yield, including variants in genes yet to be incriminated, of whole exome sequencing (WES) in familial cases of premature ovarian insufficiency (POI).

DESIGN

Cross-sectional study.

SETTING

Endocrinology and reproductive medicine teaching hospital departments.

PATIENTS

Familial POI cases were recruited as part of a nationwide multicentric cohort. A total of 36 index cases in 36 different families were studied. Fifty-two relatives were available, including 25 with POI and 27 affectedwho were nonaffected. Karyotype analysis, FMR1 screening, single nucleotide polymorphism array analysis, and WES were performed in all subjects.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The primary outcome was a molecular etiology, as diagnosed by karyotype, FMR1 screening, single nucleotide polymorphism array, and WES.

RESULTS

A likely molecular etiology (pathogenic or likely pathogenic variant) was identified in 18 of 36 index cases (50% diagnostic yield). In 12 families, we found a pathogenic or likely pathogenic variant in a gene previously incriminated in POI, and in 6 families, we found a pathogenic or likely pathogenic variant in new candidate genes. Most of the variants identified were located in genes involved in cell division and meiosis (n = 11) or DNA repair (n = 4).

CONCLUSIONS

The genetic etiologic diagnosis in POI allows for genetic familial counseling, anticipated pregnancy planning, and ovarian tissue preservation or oocyte preservation. Identifying new genes may lead to future development of therapeutics in reproduction based on disrupted molecular pathways.

CLINICAL TRIAL REGISTRATION NUMBER

NCT 01177891.

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.

Formins in Human Disease

Almost 25 years have passed since a mutation of a formin gene, DIAPH1, was identified as being responsible for a human inherited disorder: a form of sensorineural hearing loss. Since then, our knowledge of the links between formins and disease has deepened considerably. Mutations of DIAPH1 and six other formin genes (DAAM2, DIAPH2, DIAPH3, FMN2, INF2 and FHOD3) have been identified as the genetic cause of a variety of inherited human disorders, including intellectual disability, renal disease, peripheral neuropathy, thrombocytopenia, primary ovarian insufficiency, hearing loss and cardiomyopathy. In addition, alterations in formin genes have been associated with a variety of pathological conditions, including developmental defects affecting the heart, nervous system and kidney, aging-related diseases, and cancer. This review summarizes the most recent discoveries about the involvement of formin alterations in monogenic disorders and other human pathological conditions, especially cancer, with which they have been associated. In vitro results and experiments in modified animal models are discussed. Finally, we outline the directions for future research in this field.

Molecular mimicry between SARS-CoV-2 and the female reproductive system

Introduction

Oogenesis, the process of egg production by the ovary, involves a complex differentiation program leading to the production of functional oocytes. This process comprises a sequential pathway of steps that are finely regulated. The question related to SARS‐CoV‐2 infection and fertility has been evoked for several reasons, including the mechanism of molecular mimicry, which may contribute to female infertility by leading to the generation of deleterious autoantibodies, possibly contributing to the onset of an autoimmune disease in infected patients.

Objective

The immunological potential of the peptides shared between SARS‐CoV‐2 spike glycoprotein and oogenesis‐related proteins; Thus we planned a systematic study to improve our understanding of the possible effects of SARS‐CoV‐2 infection on female fertility using the angle of molecular mimicry as a starting point.

Methods

A library of 82 human proteins linked to oogenesis was assembled at random from UniProtKB database using oogenesis, uterine receptivity, decidualization, and placentation as a key words. For the analyses, an artificial polyprotein was built by joining the 82 a sequences of the oogenesis‐associated proteins. These were analyzed by searching the Immune Epitope DataBase for immunoreactive SARS‐CoV‐2 spike glycoprotein epitopes hosting the shared pentapeptides.

Results

SARS‐CoV‐2 spike glycoprotein was found to share 41 minimal immune determinants, that is, pentapeptides, with 27 human proteins that relate to oogenesis, uterine receptivity, decidualization, and placentation. All the shared pentapeptides that we identified, with the exception of four, are also present in SARS‐CoV‐2 spike glycoprotein–derived epitopes that have been experimentally validated as immunoreactive.

Human oocyte meiotic maturation is associated with a specific profile of alternatively spliced transcript isoforms

The transition from a transcriptionally active state (GV) to a transcriptionally inactive state (mature MII oocytes) is required for the acquisition of oocyte developmental competence. We hypothesize that the expression of specific genes at the in vivo matured (MII) stage could be modulated by posttranscriptional mechanisms, particularly regulation of alternative splicing (AS). In this study, we examined the transcriptional activity of GV oocytes after ovarian stimulation followed by oocyte pick-up and the landscape of alternatively spliced isoforms in human MII oocytes. Individual oocytes were processed and analyzed for transcriptional activity (GV), gene expression (GV and MII), and AS signatures (GV and MII) on HTA 2.0 microarrays. Samples were grouped according to maturation stage, and then subgrouped according to women's age and antral follicular count (AFC); array results were validated by quantitative polymerase chain reaction. Differentially expressed genes between GV and MII oocytes clustered mainly in biological processes related to mitochondrial metabolism. Interestingly, 16 genes that were related to the regulation of transcription and mitochondrial translation showed differences in alternatively spliced isoform profiles despite not being differentially expressed between groups. Altogether, our results contribute to our understanding of the role of AS in oocyte developmental competence acquisition.

A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence

Ovarian infertility and subfertility presenting with premature ovarian insufficiency (POI) and diminished ovarian reserve are major issues facing the developed world due to the trend of delaying childbirth. Ovarian senescence and POI represent a continuum of physiological/pathophysiological changes in ovarian follicle functions. Based on advances in whole exome sequencing, evaluation of gene copy variants, together with family-based and genome-wide association studies, we discussed genes responsible for POI and ovarian senescence. We used a gene-centric approach to sort out literature deposited in the Ovarian Kaleidoscope database (http://okdb.appliedbioinfo.net) by sub-categorizing candidate genes as ligand-receptor signaling, meiosis and DNA repair, transcriptional factors, RNA metabolism, enzymes, and others. We discussed individual gene mutations found in POI patients and verification of gene functions in gene-deleted model organisms. Decreased expression of some of the POI genes could be responsible for ovarian senescence, especially those essential for DNA repair, meiosis and mitochondrial functions. We propose to set up a candidate gene panel for targeted sequencing in POI patients together with studies on mitochondria-associated genes in middle-aged subfertile patients.

Nonredundant roles of DIAPHs in primary ciliogenesis

Primary cilia are hubs for several signaling pathways, and disruption in cilia function and formation leads to a range of diseases collectively known as ciliopathies. Both ciliogenesis and cilia maintenance depend on vesicle trafficking along a network of microtubules and actin filaments toward the basal body. The DIAPH (Diaphanous-related) family of formins promote both actin polymerization and microtubule (MT) stability. Recently, we showed that the formin DIAPH1 is involved in ciliogenesis. However, the role of other DIAPH family members in ciliogenesis had not been investigated. Here we show that depletion of either DIAPH2 or DIAPH3 also disrupted ciliogenesis and cilia length. DIAPH3 depletion also reduced trafficking within cilia. To specifically examine the role of DIAPH3 at the base, we used fused full-length DIAPH3 to centrin, which targeted DIAPH3 to the basal body, causing increased trafficking to the ciliary base, an increase in cilia length, and formation of bulbs at the tips of cilia. Additionally, we confirmed that the microtubule-stabilizing properties of DIAPH3 are important for its cilia length functions and trafficking. These results indicate the importance of DIAPH proteins in regulating cilia maintenance. Moreover, defects in ciliogenesis caused by DIAPH depletion could only be rescued by expression of the specific family member depleted, indicating nonredundant roles for these proteins.

Ovarian Fragmentation and AKT Stimulation for Expansion of Fertile Lifespan

Since the first baby was born after in vitro fertilization, the female infertility treatment has been well-developed, yielding successful outcomes. However, successful pregnancies for patients with premature ovarian insufficiency and diminished ovarian reserve are still difficult and diverse therapies have been suggested to improve the chances to have their genetically linked offspring. Recent studies demonstrated that the activation Akt pathway by using a phosphatase and tensin homolog enzyme inhibitor and a phosphatidylinositol-3 kinase stimulator can activate dormant primordial follicles in both mice and human ovaries. Subsequent researches suggested that the disruption of Hippo signaling pathway by ovarian fragmentation increased the expression of downstream growth factors and secondary follicle growth. Based on the combination of ovarian fragmentation and Akt stimulation, the in vitro activation (IVA) approach has resulted in successful follicle growth and live births in premature ovarian insufficiency patients. The approach with disruption of Hippo signaling only was also shown to be effective for treating poor ovarian responders with diminishing ovarian reserve, including advanced age women and cancer patients undergoing sterilizing treatments. This review aims to summarize the effectiveness of ovarian fragmentation and Akt stimulation on follicle growth and the potential of IVA in extending female fertile lifespan.

Characterization of reproductive gene diversity in the endangered Tasmanian devil

Interindividual variation at genes known to play a role in reproduction may impact reproductive fitness. The Tasmanian devil is an endangered Australian marsupial with low genetic diversity. Recent work has shown concerning declines in productivity in both wild and captive populations over time. Understanding whether functional diversity exists at reproductive genes in the Tasmanian devil is a key first step in identifying genes that may influence productivity. We characterized single nucleotide polymorphisms (SNPs) at 214 genes involved in reproduction in 37 Tasmanian devils. Twenty genes contained nonsynonymous substitutions, with genes involved in embryogenesis, fertilization and hormonal regulation of reproduction displaying greater numbers of nonsynonymous SNPs than synonymous SNPs. Two genes, ADAMTS9 and NANOG, showed putative signatures of balancing selection indicating that natural selection is maintaining diversity at these genes despite the species exhibiting low overall levels of genetic diversity. We will use this information in future to examine the interplay between reproductive gene variation and reproductive fitness in Tasmanian devil populations.

Colorectal Adenocarcinomas Harboring ALK Fusion Genes: A Clinicopathologic and Molecular Genetic Study of 12 Cases and Review of the Literature

This study determined the frequency and the clinicopathologic and genetic features of colorectal carcinomas driven by oncogenic fusions of the anaplastic lymphoma kinase gene (ALK). Of the 8150 screened tumors, 12 (0.15%) were immunohistochemically ALK-positive with D5F3 antibody. These cancers harbored CAD-ALK (n=1), DIAPH2-ALK (n=2), EML4-ALK (n=2), LOC101929227-ALK (n=1), SLMAP-ALK (n=1), SPTBN1-ALK (n=4), and STRN-ALK (n=1) fusions, as detected by an RNA-based next-generation sequencing assay. ALK fusion carcinomas were diagnosed mostly in older patients with a 9:3 female predominance (median age: 72 y). All tumors, except a rectal one, occurred in the right colon. Most tumors were stage T3 (n=7) or T4 (n=3). Local lymph node and distant metastases were seen at presentation in 9 and 2 patients. These tumors showed moderate (n=6) or poor (n=3) glandular differentiation, solid medullary growth pattern (n=2), and pure mucinous morphology (n=1). DNA mismatch repair-deficient phenotype was identified in 10 cases. Tumor-infiltrating lymphocytes were prominent in 9 carcinomas. In 4 carcinomas, tumor cells showed strong, focal (n=3), or diffuse programmed death-ligand 1 immunoreactivity. CDX2 expression and loss of CK20 and MUC2 expression were frequent. CK7 was expressed in 5 tumors. Four patients died of disease within 3 years, and 7 were alive with follow-up ranging from 1 to 8 years. No mutations in BRAF, RAS, and in genes encoding components of PI3K-AKT/MTOR pathway were identified. However, 1 tumor had a loss-of-function PTEN mutation. Aberration of p53 signaling, TP53 mutations, and/or nuclear accumulation of p53 protein was seen in 9 cases. ALK fusion colorectal carcinomas are a distinct and rare subtype of colorectal cancers displaying some features of mismatch repair-deficient tumors.

Hippo signaling disruption and ovarian follicle activation in infertile patients

The Hippo signaling pathway, which is important in organ size regulation, is present in organisms from the fly to mammals. Disruption of the Hippo signaling pathway leads to increased nuclear translocation of the effector Yes-associated protein (YAP), resulting in the expression of cystein-rich 61, connective tissue growth factor, and nephroblastoma overexpressed (CCN) growth factors and baculoviral inhibitors of apoptosis repeat containing (BIRC) apoptosis inhibitors to increase organ sizes. Furthermore, genome-wide knockdown of genes in insect cells demonstrated that actin polymerization promoted nuclear translocation of YAP. In the mammalian ovary, we demonstrated the expression of Hippo signaling pathway genes and showed that ovarian fragmentation increased actin polymerization, leading to YAP nuclear translocation and increased expression of cystein-rich 61, CCN growth factors and BIRC apoptosis inhibitors, followed by enhanced follicle growth. Here we summarize evidence suggesting the role of mechanical stress on follicle growth in the ovary and describe recent use of ovary-damaging procedures to treat ovarian infertility. Ovarian fragmentation, together with in vitro incubation with Akt-stimulating drugs, formed the basis of an in vitro activation (IVA) therapy to treat patients with premature ovarian insufficiency, whereas ovarian fragmentation alone (drug-free IVA) was successful in treating patients with premature ovarian insufficiency with recent menses cessation. For middle-aged women with poor ovarian responses and diminished ovarian reserve, drug-free IVA was also effective in promoting follicle growth for infertility treatment. In addition, an in vivo follicle activation approach based on laparoscopic ovarian incision showed promise for patients with resistant ovary syndrome. With initial success using mechanical disruption approaches, future investigation could evaluate possibilities to refine mechanical methods and to locally administer actin polymerization-enhancing drugs for ovarian infertility treatment.

Genetics of Primary Ovarian Insufficiency in the Next-Generation Sequencing Era

Primary ovarian insufficiency (POI) is characterized by amenorrhea, increased follicle-stimulating hormone (FSH) levels, and hypoestrogenism, leading to infertility before the age of 40 years. Elucidating the cause of POI is a key point for diagnosing and treating affected women. Here, we review the genetic etiology of POI, highlighting new genes identified in the last few years using next-generation sequencing (NGS) approaches. We searched the MEDLINE/PubMed, Cochrane, and Web of Science databases for articles published in or translated to English. Several genes were found to be associated with POI genetic etiology in humans and animal models (SPIDR, BMPR2, MSH4, MSH5, GJA4, FANCM, POLR2C, MRPS22, KHDRBS1, BNC1, WDR62, ATG7/ATG9, BRCA2, NOTCH2, POLR3H, and TP63). The heterogeneity of POI etiology has been revealed to be remarkable in the NGS era, and discoveries have indicated that meiosis and DNA repair play key roles in POI development.

The Use of Whole Exome Sequencing in a Cohort of Transgender Individuals to Identify Rare Genetic Variants

Approximately 0.5-1.4% of natal males and 0.2-0.3% of natal females meet DSM-5 criteria for gender dysphoria, with many of these individuals self-describing as transgender men or women. Despite recent improvements both in social acceptance of transgender individuals as well as access to gender affirming therapy, progress in both areas has been hampered by poor understanding of the etiology of gender dysphoria. Prior studies have suggested a genetic contribution to gender dysphoria, but previously proposed candidate genes have not yet been verified in follow-up investigation. In this study, we expand on the topic of gender identity genomics by identifying rare variants in genes associated with sexually dimorphic brain development and exploring how they could contribute to gender dysphoria. To accomplish this, we performed whole exome sequencing on the genomic DNA of 13 transgender males and 17 transgender females. Whole exome sequencing revealed 120,582 genetic variants. After filtering, 441 variants in 421 genes remained for further consideration, including 21 nonsense, 28 frameshift, 13 splice-region, and 225 missense variants. Of these, 21 variants in 19 genes were found to have associations with previously described estrogen receptor activated pathways of sexually dimorphic brain development. These variants were confirmed by Sanger Sequencing. Our findings suggest a new avenue for investigation of genes involved in estrogen signaling pathways related to sexually dimorphic brain development and their relationship to gender dysphoria.

Human Papillomavirus Epitope Mimicry and Autoimmunity: The Molecular Truth of Peptide Sharing

OBJECTIVE

To define the cross-reactivity potential and the consequent autoimmunity intrinsic to viral versus human peptide sharing.

METHODS

Using human papillomavirus (HPV) infection/active immunization as a research model, the experimentally validated HPV L1 epitopes catalogued at the Immune Epitope DataBase were analyzed for peptide sharing with the human proteome.

RESULTS

The final data show that the totality of the immunoreactive HPV L1 epi-topes is mostly composed by peptides present in human proteins.

CONCLUSIONS

Immunologically, the high extent of peptide sharing between the HPV L1 epitopes and human proteins invites to revise the concept of the negative selection of self-reactive lymphocytes. Pathologically, the data highlight a cross-reactive potential for a spectrum of autoimmune diseases that includes ovarian failure, systemic lupus erythematosus (SLE), breast cancer and sudden death, among others. Therapeutically, analyzing already validated immunoreactive epitopes filters out the peptide sharing possibly exempt of self-reactivity, defines the effective potential for pathologic autoimmunity, and allows singling out peptide epitopes for safe immunotherapeutic protocols.

Sex chromosomes-linked single-gene disorders involved in human infertility

Human infertility is a healthcare problem that has a worldwide impact. Genetic causes of human infertility include chromosomal aneuploidies and rearrangements and single-gene defects. The sex chromosomes (X and Y) are critical players in human fertility since they contain several genes essential for sex determination and reproductive traits for both men and women. This paper provides a review of the most common sex chromosomes-linked single-gene disorders involved in human infertility and their corresponding phenotypes. In addition to the Y-linked SRY gene, which mutations may cause XY gonadal dysgenesis and sex reversal, the deletions of genes present in AZF regions of the Y chromosome (DAZ, RBMY, DBY and USP9Y genes) are implicated in varying degrees of spermatogenic dysfunction. Furthermore, a list of X-linked genes (KAL1, NR0B1, AR, TEX11, FMR1, PGRMC1, BMP15 and POF1 and 2 regions genes (XPNPEP2, POF1B, DACH2, CHM and DIAPH2)) were reported to have critical roles in pubertal and reproductive deficiencies in humans, affecting only men, only women or both sexes. Mutations in these genes may be transmitted to the offspring by a dominant or a recessive inheritance.

Cell-intrinsic and -extrinsic mechanisms promote cell-type-specific cytokinetic diversity

Cytokinesis, the physical division of one cell into two, is powered by constriction of an actomyosin contractile ring. It has long been assumed that all animal cells divide by a similar molecular mechanism, but growing evidence suggests that cytokinetic regulation in individual cell types has more variation than previously realized. In the four-cell Caenorhabditis elegans embryo, each blastomere has a distinct cell fate, specified by conserved pathways. Using fast-acting temperature-sensitive mutants and acute drug treatment, we identified cell-type-specific variation in the cytokinetic requirement for a robust formin^CYK-1-dependent filamentous-actin (F-actin) cytoskeleton. In one cell (P2), this cytokinetic variation is cell-intrinsically regulated, whereas in another cell (EMS) this variation is cell-extrinsically regulated, dependent on both Src^SRC-1 signaling and direct contact with its neighbor cell, P2. Thus, both cell-intrinsic and -extrinsic mechanisms control cytokinetic variation in individual cell types and can protect against division failure when the contractile ring is weakened.

The successful division of one cell into two is essential for all organisms to live, grow and reproduce. For an animal cell, the nucleus – the compartment containing the genetic material – must divide before the surrounding material. The rest of the cell, called the cytoplasm, physically separates later in a process known as cytokinesis.

Cytokinesis in animal cells is driven by the formation of a ring in the middle of the dividing cell. The ring is composed of myosin motor proteins and filaments made of a protein called actin. The movements of the motor proteins along the filaments cause the ring to contract and tighten. This pulls the cell membrane inward and physically pinches the cell into two. For a long time, the mechanism of cytokinesis was assumed to be same across different types of animal cell, but later evidence suggested otherwise. For example, in liver, heat and bone cells, cytokinesis naturally fails during development to create cells with two or more nuclei. If a similar ‘failure’ happened in other cell types, it could lead to diseases such as cancers or blood disorders. This raised the question: what are the molecular mechanisms that allow cytokinesis to happen differently in different cell types?

Davies et al. investigated this question using embryos of the worm Caenorhabditis elegans at a stage in their development when they consist of just four cells. The proteins forming the contractile ring in this worm are the same as those in humans. However, in the worm, the contractile ring can easily be damaged using chemical inhibitors or by mutating the genes that encode its proteins.

Davies et al. show that when the contractile ring was damaged, two of the four cells in the worm embryo still divided successfully. This result indicates the existence of new mechanisms to divide the cytoplasm that allow division even with a weak contractile ring. In a further experiment, the embryos were dissected to isolate each of the four cells. Davies et al. saw that one of the two dividing cells could still divide on its own, while the other cell could not. This shows that this new method of cytokinesis is regulated both by factors inherent to the dividing cell and by external signals from other cells. Moreover, one of these extrinsic signals was found to be a signaling protein that had previously been implicated in human cancers.

Future work will determine if these variations in cytokinesis between the different cell types found in the worm apply to humans too; and, more importantly from a therapeutic standpoint, if these new mechanisms exist in human cancers.

Differential Toxicity of mDia Formin-Directed Functional Agonists and Antagonists in Developing Zebrafish

The mammalian Diaphanous-related (mDia) formins are cytoskeletal regulators that assemble and, in some cases, bundle filamentous actin (F-actin), as well as stabilize microtubules. The development of small molecule antagonists and agonists that interrogate mDia formin function has allowed us to investigate the roles of formins in disease states. A small molecule inhibitor of FH2 domain (SMIFH2) inhibits mDia-dependent actin dynamics and abrogates tumor cell migration and cell division in vitro and ex vivo tissue explants. mDia formin activation with small molecule intramimics IMM01/02 and mDia2-DAD peptides inhibited glioblastoma motility and invasion in vitro and ex vivo rat brain slices. However, SMIFH2, IMMs, and mDia2 DAD efficacy in vivo remains largely unexplored and potential toxicity across a range of developmental phenotypes has not been thoroughly characterized. In this study, we performed an in vivo screen of early life-stage toxicity in Danio rerio zebrafish embryos 2 days post-fertilization (dpf) in response to SMIFH2, IMM01/02, and mDia2 DAD. SMIFH2 at concentrations ≥5–10 μM induced significant defects in developing zebrafish, including shorter body lengths, tail curvature and defective tail cellularity, craniofacial malformations, pericardial edema, absent and/or compromised vasculature function and flow, depressed heart rates and increased mortality. Conversely, IMM and mDia2 DAD peptides were minimally toxic at concentrations up to 10–20 and 50 μM, respectively. SMIFH2's therapeutic potential may therefore be limited by its substantial in vivo toxicity at functional concentrations. mDia formin agonism with IMMs and mDia2 DADs may therefore be a more effective and less toxic anti-invasive therapeutic approach.

Primary ovarian insufficiency in classic galactosemia: current understanding and future research opportunities

Classic galactosemia is an inborn error of the metabolism with devastating consequences. Newborn screening has been successful in markedly reducing the acute neonatal symptoms from this disorder. The dramatic response to dietary treatment is one of the major success stories of newborn screening. However, as children with galactosemia achieve adulthood, they face long-term complications. A majority of women with classic galactosemia develop primary ovarian insufficiency and resulting morbidity. The underlying pathophysiology of this complication is not clear. This review focuses on the reproductive issues seen in girls and women with classic galactosemia. Literature on the effects of classic galactosemia on the female reproductive system was reviewed by an extensive Pubmed search (publications from January 1975 to January 2017) using the keywords: galactosemia, ovarian function/dysfunction, primary ovarian insufficiency/failure, FSH, oxidative stress, fertility preservation. In addition, articles cited in the search articles and literature known to the authors was also included in the review. Our understanding of the role of galactose metabolism in the ovary is limited and the pathogenic mechanisms involved in causing primary ovarian insufficiency are unclear. The relative rarity of galactosemia makes it difficult to accumulate data to determine factors defining timing of ovarian dysfunction or treatment/fertility preservation options for this group of women. In this review, we present reproductive challenges faced by women with classic galactosemia, highlight the gaps in our understanding of mechanisms leading to primary ovarian insufficiency in this population, discuss new advances in fertility preservation options, and recommend collaboration between reproductive medicine and metabolic specialists to improve fertility in these women.

ZP3 is Required for Germinal Vesicle Breakdown in Mouse Oocyte Meiosis

ZP3 is a principal component of the zona pellucida (ZP) of mammalian oocytes and is essential for normal fertility, and knockout of ZP3 causes complete infertility. ZP3 promotes fertilization by recognizing sperm binding and activating the acrosome reaction; however, additional cellular roles for ZP3 in mammalian oocytes have not been yet reported. In the current study, we found that ZP3 was strongly expressed in the nucleus during prophase and gradually translocated to the ZP. Knockdown of ZP3 by a specific siRNA dramatically inhibited germinal vesicle breakdown (GVBD) (marking the beginning of meiosis), significantly reducing the percentage of MII oocytes. To investigate the ZP3-mediated mechanisms governing GVBD, we identified potential ZP3-interacting proteins by immunoprecipitation and mass spectrometry. We identified Protein tyrosine phosphatase, receptor type K (Ptprk), Aryl hydrocarbon receptor-interacting protein-like 1 (Aipl1), and Diaphanous related formin 2 (Diaph2) as potential candidates, and established a working model to explain how ZP3 affects GVBD. Finally, we provided preliminary evidence that ZP3 regulates Akt phosphorylation, lamin binding to the nuclear membrane via Aipl1, and organization of the actin cytoskeleton via Diaph2. These findings contribute to our understanding of a novel role played by ZP3 in GVBD.

A case of 46,XX dysgenesis and marked tall stature; the need for caution in interpreting array comparative genomic hybridization (CGH)

BACKGROUND

Gonadal dysgenesis with an apparently normal 46,XX karyotype is a rare cause of hypergonadotrophic hypogonadism. Tall stature is not a widely recognized association.

CASE REPORT

A 15-year-old girl presented with primary amenorrhoea. Examination showed a non-dysmorphic girl of normal intellect with no breast development (Tanner stage B1P4A1) who was tall compared with her parents: height standard deviation score (SDS) +1.56 vs. midparental height of +0.23 SDS, and slim build (weight -0.13 SDS). Investigations showed a 46,XX karyotype, elevated gonadotropins (FSH 119 and LH 33.7 IU/L), serum estradiol <5 pmol/L, uterine length 3.75 cm with cylindrical shape, and absent ovaries on ultrasound. Initially, a 364055-bp deletion on Xp21.2 was reported on array CGH. However, repeat analysis using BlueGnome CytoChip ISCA 4x180k v2.0 array was normal. With oral ethinyl estradiol induction puberty progressed to B4P4A2 but aged 18.4 years, the patient was remarkably tall with height SDS +2.88, weight SDS +0.97.

CONCLUSIONS

Caution is needed in interpreting small changes with array CGH, particularly with the older assays. We postulate that the genetic change causing 46,XX gonadal dysgenesis in our patient may have also resulted in unsuppressed somatic growth. More critical height assessment, including parental height measurement, of future patients with 46,XX gonadal dysgenesis is recommended in order to determine whether or not a true association with tall stature may be present in certain cases.

Utility of Lymphoblastoid Cell Lines for Induced Pluripotent Stem Cell Generation

A large number of EBV immortalized LCLs have been generated and maintained in genetic/epidemiological studies as a perpetual source of DNA and as a surrogate in vitro cell model. Recent successes in reprograming LCLs into iPSCs have paved the way for generating more relevant in vitro disease models using this existing bioresource. However, the overall reprogramming efficiency and success rate remain poor and very little is known about the mechanistic changes that take place at the transcriptome and cellular functional level during LCL-to-iPSC reprogramming. Here, we report a new optimized LCL-to-iPSC reprogramming protocol using episomal plasmids encoding pluripotency transcription factors and mouse p53DD (p53 carboxy-terminal dominant-negative fragment) and commercially available reprogramming media. We achieved a consistently high reprogramming efficiency and 100% success rate using this optimized protocol. Further, we investigated the transcriptional changes in mRNA and miRNA levels, using FC-abs ≥ 2.0 and FDR ≤ 0.05 cutoffs; 5,228 mRNAs and 77 miRNAs were differentially expressed during LCL-to-iPSC reprogramming. The functional enrichment analysis of the upregulated genes and activation of human pluripotency pathways in the reprogrammed iPSCs showed that the generated iPSCs possess transcriptional and functional profiles very similar to those of human ESCs.

Drosophila homologue of Diaphanous 1 (DIAPH1) controls the metastatic potential of colon cancer cells by regulating microtubule-dependent adhesion

Drosophila homologue of Diaphanous 1 (DIAPH1) regulates actin polymerization and microtubule (MT) stabilization upon stimulation with lysophosphatidic acid (LPA). Recently, we showed strongly reduced lung metastasis of DIAPH1-depleted colon cancer cells but we found accumulations of DIAPH1-depleted cells in bone marrow. Here, we analyzed possible organ- or tissue-specific metastasis of DIAPH1-depleted HCT-116 cells. Our data confirmed that depletion of DIAPH1 strongly inhibited lung metastasis and revealed that, in contrast to control cells, DIAPH1-depleted cells did not form metastases in further organs. Detailed mechanistic analysis on cells that were not stimulated with LPA to activate the cytoskeleton-modulating activity of DIAPH1, revealed that even under basal conditions DIAPH1 was essential for cellular adhesion to collagen. In non-stimulated cells DIAPH1 did not control actin dynamics but, interestingly, was essential for stabilization of microtubules (MTs). Additionally, DIAPH1 controlled directed vesicle trafficking and with this, local clustering of the adhesion protein integrin-β1 at the plasma membrane. Therefore, we conclude that under non-stimulating conditions DIAPH1 controls cellular adhesion by stabilizing MTs required for local clustering of integrin-β1 at the plasma membrane. Thus, blockade of DIAPH1-tubulin interaction may be a promising approach to inhibit one of the earliest steps in the metastatic cascade of colon cancer.

Molecular insights into the aetiology of female reproductive ageing

As age at pubertal onset declines and age at first pregnancy increases, the mechanisms that regulate female reproductive lifespan become increasingly relevant to population health. The timing of menarche and menopause can have profound effects not only on fertility but also on the risk of diseases such as type 2 diabetes mellitus, cardiovascular disease and breast cancer. Genetic studies have identified dozens of highly penetrant rare mutations associated with reproductive disorders, and also ∼175 common genetic variants associated with the timing of puberty or menopause. These findings, alongside other functional studies, have highlighted a diverse range of mechanisms involved in reproductive ageing, implicating core biological processes such as cell cycle regulation and energy homeostasis. The aim of this article is to review the contribution of such genetic findings to our understanding of the molecular regulation of reproductive timing, as well as the biological basis of the epidemiological links between reproductive ageing and disease risk.

Strong Constraint on Human Genes Escaping X-Inactivation Is Modulated by their Expression Level and Breadth in Both Sexes

In eutherian mammals, X-linked gene expression is normalized between XX females and XY males through the process of X chromosome inactivation (XCI). XCI results in silencing of transcription from one ChrX homolog per female cell. However, approximately 25% of human ChrX genes escape XCI to some extent and exhibit biallelic expression in females. The evolutionary basis of this phenomenon is not entirely clear, but high sequence conservation of XCI escapers suggests that purifying selection may directly or indirectly drive XCI escape at these loci. One hypothesis is that this signal results from contributions to developmental and physiological sex differences, but presently there is limited evidence supporting this model in humans. Another potential driver of this signal is selection for high and/or broad gene expression in both sexes, which are strong predictors of reduced nucleotide substitution rates in mammalian genes. Here, we compared purifying selection and gene expression patterns of human XCI escapers with those of X-inactivated genes in both sexes. When we accounted for the functional status of each ChrX gene’s Y-linked homolog (or “gametolog”), we observed that XCI escapers exhibit greater degrees of purifying selection in the human lineage than X-inactivated genes, as well as higher and broader gene expression than X-inactivated genes across tissues in both sexes. These results highlight a significant role for gene expression in both sexes in driving purifying selection on XCI escapers, and emphasize these genes’ potential importance in human disease.

Poreless eggshells

The oocyte is the sole source of the female genetic material that will be fertilized by sperm to form an embryo. Many extrinsic and intrinsic factors are critical for oocyte development and survival; however, these mediators are incompletely understood. In this issue of the JCI, Weinberg-Shukron et al. uncover a novel recessive missense mutation in the gene encoding nucleoporin-107 (NUP107) that results in abnormal ovarian development. Recapitulation of the human mutation in the Drosophila NUP107 ortholog resulted in poor follicular development and demonstrated an evolutionarily conserved and ovary-specific role of NUP107. While NUP107 is required for nuclear pore complex function in somatic cells of flies and women, this specific amino acid change appears only to be disruptive in the ovary. All together, these findings imply that missense mutations in other genes could be specifically disruptive of ovarian or testicular function, while leaving extragonadal function intact.

A mutation in the nucleoporin-107 gene causes XX gonadal dysgenesis

Ovarian development and maintenance are poorly understood; however, diseases that affect these processes can offer insights into the underlying mechanisms. XX female gonadal dysgenesis (XX-GD) is a rare, genetically heterogeneous disorder that is characterized by underdeveloped, dysfunctional ovaries, with subsequent lack of spontaneous pubertal development, primary amenorrhea, uterine hypoplasia, and hypergonadotropic hypogonadism. Here, we report an extended consanguineous family of Palestinian origin, in which 4 females exhibited XX-GD. Using homozygosity mapping and whole-exome sequencing, we identified a recessive missense mutation in nucleoporin-107 (NUP107, c.1339G>A, p.D447N). This mutation segregated with the XX-GD phenotype and was not present in available databases or in 150 healthy ethnically matched controls. NUP107 is a component of the nuclear pore complex, and the NUP107-associated protein SEH1 is required for oogenesis in Drosophila. In Drosophila, Nup107 knockdown in somatic gonadal cells resulted in female sterility, whereas males were fully fertile. Transgenic rescue of Drosophila females bearing the Nup107D364N mutation, which corresponds to the human NUP107 (p.D447N), resulted in almost complete sterility, with a marked reduction in progeny, morphologically aberrant eggshells, and disintegrating egg chambers, indicating defective oogenesis. These results indicate a pivotal role for NUP107 in ovarian development and suggest that nucleoporin defects may play a role in milder and more common conditions such as premature ovarian failure.

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.

Genetics of primary ovarian insufficiency: new developments and opportunities

BACKGROUND

Primary ovarian insufficiency (POI) is characterized by marked heterogeneity, but with a significant genetic contribution. Identifying exact causative genes has been challenging, with many discoveries not replicated. It is timely to take stock of the field, outlining the progress made, framing the controversies and anticipating future directions in elucidating the genetics of POI.

METHODS

A search for original articles published up to May 2015 was performed using PubMed and Google Scholar, identifying studies on the genetic etiology of POI. Studies were included if chromosomal analysis, candidate gene screening and a genome-wide study were conducted. Articles identified were restricted to English language full-text papers.

RESULTS

Chromosomal abnormalities have long been recognized as a frequent cause of POI, with a currently estimated prevalence of 10-13%. Using the traditional karyotype methodology, monosomy X, mosaicism, X chromosome deletions and rearrangements, X-autosome translocations, and isochromosomes have been detected. Based on candidate gene studies, single gene perturbations unequivocally having a deleterious effect in at least one population include Bone morphogenetic protein 15 (BMP15), Progesterone receptor membrane component 1 (PGRMC1), and Fragile X mental retardation 1 (FMR1) premutation on the X chromosome; Growth differentiation factor 9 (GDF9), Folliculogenesis specific bHLH transcription factor (FIGLA), Newborn ovary homeobox gene (NOBOX), Nuclear receptor subfamily 5, group A, member 1 (NR5A1) and Nanos homolog 3 (NANOS3) seem likely as well, but mostly being found in no more than 1-2% of a single population studied. Whole genome approaches have utilized genome-wide association studies (GWAS) to reveal loci not predicted on the basis of a candidate gene, but it remains difficult to locate causative genes and susceptible loci were not always replicated. Cytogenomic methods (array CGH) have identified other regions of interest but studies have not shown consistent results, the resolution of arrays has varied and replication is uncommon. Whole-exome sequencing in non-syndromic POI kindreds has only recently begun, revealing mutations in the Stromal antigen 3 (STAG3), Synaptonemal complex central element 1 (SYCE1), minichromosome maintenance complex component 8 and 9 (MCM8, MCM9) and ATP-dependent DNA helicase homolog (HFM1) genes. Given the slow progress in candidate-gene analysis and relatively small sample sizes available for GWAS, family-based whole exome and whole genome sequencing appear to be the most promising approaches for detecting potential genes responsible for POI.

CONCLUSION

Taken together, the cytogenetic, cytogenomic (array CGH) and exome sequencing approaches have revealed a genetic causation in ∼20-25% of POI cases. Uncovering the remainder of the causative genes will be facilitated not only by whole genome approaches involving larger cohorts in multiple populations but also incorporating environmental exposures and exploring signaling pathways in intragenic and intergenic regions that point to perturbations in regulatory genes and networks.

GeneWeaver: finding consilience in heterogeneous cross-species functional genomics data

A persistent challenge lies in the interpretation of consensus and discord from functional genomics experimentation. Harmonizing and analyzing this data will enable investigators to discover relations of many genes to many diseases, and from many phenotypes and experimental paradigms to many diseases through their genomic substrates. The GeneWeaver.org system provides a platform for cross-species integration and interrogation of heterogeneous curated and experimentally derived functional genomics data. GeneWeaver enables researchers to store, share, analyze, and compare results of their own genome-wide functional genomics experiments in an environment containing rich companion data obtained from major curated repositories, including the Mouse Genome Database and other model organism databases, along with derived data from highly specialized resources, publications, and user submissions. The data, largely consisting of gene sets and putative biological networks, are mapped onto one another through gene identifiers and homology across species. A versatile suite of interactive tools enables investigators to perform a variety of set analysis operations to find consilience among these often noisy experimental results. Fast algorithms enable real-time analysis of large queries. Specific applications include prioritizing candidate genes for quantitative trait loci, identifying biologically valid mouse models and phenotypic assays for human disease, finding the common biological substrates of related diseases, classifying experiments and the biological concepts they represent from empirical data, and applying patterns of genomic evidence to implicate novel genes in disease. These results illustrate an alternative to strict emphasis on replicability, whereby researchers classify experimental results to identify the conditions that lead to their similarity.

Premature ovarian failure caused by a heterozygous missense mutation in POF1B and a reciprocal translocation 46,X,t(X;3)(q21.1;q21.3)

In a patient affected by premature ovarian failure, a reciprocal translocation between chromosomes X and 3 and an additional heterozygous missense mutation in the X-linked gene POF1B were detected. Homozygosity for POF1B mutations is well-known to be associated with premature ovarian failure. In this case, the rare combination of skewed X inactivation due to the reciprocal translocation involving one X chromosome and heterozygosity for a known POF1B mutation explains the phenotype.

Intraovarian control of early folliculogenesis

Although hormonal regulation of ovarian follicle development has been extensively investigated, most studies concentrate on the development of early antral follicles to the preovulatory stage, leading to the successful use of exogenous FSH for infertility treatment. Accumulating data indicate that preantral follicles are under stringent regulation by FSH and local intraovarian factors, thus providing the possibility to develop new therapeutic approaches. Granulosa cell-derived C-type natriuretic factor not only suppresses the final maturation of oocytes to undergo germinal vesicle breakdown before ovulation but also promotes preantral and antral follicle growth. In addition, several oocyte- and granulosa cell-derived factors stimulate preantral follicle growth by acting through wingless, receptor tyrosine kinase, receptor serine kinase, and other signaling pathways. In contrast, the ovarian Hippo signaling pathway constrains follicle growth and disruption of Hippo signaling promotes the secretion of downstream CCN growth factors capable of promoting follicle growth. Although the exact hormonal factors involved in primordial follicle activation has yet to be elucidated, the protein kinase B (AKT) and mammalian target of rapamycin signaling pathways are important for the activation of dormant primordial follicles. Hippo signaling disruption after ovarian fragmentation, combined with treating ovarian fragments with phosphatase and tensin homolog (PTEN) inhibitors and phosphoinositide-3-kinase stimulators to augment AKT signaling, promote the growth of preantral follicles in patients with primary ovarian insufficiency, leading to a new infertility intervention for such patients. Elucidation of intraovarian mechanisms underlying early folliculogenesis may allow the development of novel therapeutic strategies for patients diagnosed with primary ovarian insufficiency, polycystic ovary syndrome, and poor ovarian response to FSH stimulation, as well as for infertile women of advanced reproductive age.

Differentiation of primordial germ cells from induced pluripotent stem cells of primary ovarian insufficiency

STUDY QUESTION

Can the induced pluripotent stem cells (iPSCs) derived from women with primary ovarian insufficiency (POI) differentiate into germ cells for potential disease modeling in vitro?

SUMMARY ANSWER

The iPSC lines derived from POI patients with 46, X, del(X)(q26) or 46, X, del(X)(q26)9qh+ could differentiate into germ cells and expressed lower levels of genes in the deletion region of the X chromosome.

WHAT IS KNOWN ALREADY

iPSC technology has been envisioned as an approach for generating patient-specific stem cells for disease modeling and for developing novel therapies. It has also been confirmed that iPSCs differentiate into germ cells.

STUDY DESIGN, SIZE, DURATION

We compared the differentiation ability of germ cells and the gene expression level of germ cell-related genes in the X chromosome deletion region of iPSC lines derived from POI patients (n = 2) with an iPSC line derived from normal fibroblasts (n = 1).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We established three iPSC lines from two patients with partial Xq deletion-induced POI and normal fibroblasts by overexpressing four factors: octamer-binding transcription factor 4 (OCT4), sex-determining region Y-box 2 (SOX2), Nanog homeobox (NANOG), and lin-28 homolog (LIN28), using lentiviral vectors. We then generated stable-transfected fluorescent reporter cell lines under the control of the Asp-Glu-Ala-Asp box polypeptide 4 (DDX4, also called VASA) promoter, and selected clonal derived sublines. We induced subline differentiation into germ cells by adding Wnt3a (30 ng/ml) and bone morphogenetic protein 4 (100 ng/ml). After 12 days of differentiation, green fluorescent protein (GFP)-positive and GFP-negative cells were isolated via fluorescence-activated cell sorting and analyzed for endogenous VASA protein (immunostaining) and for germ cell markers and genes expressed in the deleted region of the X chromosome (quantitative RT-PCR).

MAIN RESULTS AND THE ROLE OF CHANCE

The POI- and normal fibroblast-derived iPSCs had typical self-renewal and pluripotency characteristics. After stable transfection with the VASA-GFP construct, the sublines POI1-iPS-V.1, POI2-iPS-V.1 and hEF-iPS-V.1 produced green fluorescent cells in the differentiated cultures, and the percentage of GFP-positive cells increased over the 12 days of differentiation to a maximum of 6.9 ± 0.33%, 5.3 ± 0.57% and 8.5 ± 0.29%, respectively, of the total cell population. Immunohistochemical analysis confirmed that endogenous VASA was enriched in the GFP-positive cells. Quantitative reverse transcription-PCR revealed significantly higher expression of germ cell markers [PR domain containing 1, with ZNF domain (PRDM1, BLIMP1), developmental pluripotency-associated 3 (DPPA3, STELLA), deleted in azoospermia-like (DAZL), and VASA (DDX4)] in GFP-positive cells than in GFP-negative cells. Moreover, the GFP-positive cells from POI-iPSCs had reduced expression of the family with sequence similarity 122C (FAM122C), inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase gamma (IKBKG), and RNA binding motif protein, X-linked (RBMX), genes located in the deleted region of the X chromosome and that are highly expressed in differentiated germ cells, compared with cells from normal iPSCs.

LIMITATIONS, REASONS FOR CAUTION

Gene expression profiling indicated that the germ cells differentiated from POI-iPSCs were pre-meiotic. Therefore, how the differentiated primordial germ cells could progress further to meiosis and form follicles remains to be determined in the study of POI.

WIDER IMPLICATIONS OF THE FINDINGS

Our results might provide an in vitro model for studying germ cell development in patients with POI.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by grants from the Major State Basic Research Development Program of China (No. 2012CB944901), the National Science Foundation of China (No. 81222007 and 81471432), the Program for New Century Excellent Talents in University and the Fundamental Research Funds for Central Universities (No. 721500003). The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Identifying a novel role for X-prolyl aminopeptidase (Xpnpep) 2 in CrVI-induced adverse effects on germ cell nest breakdown and follicle development in rats

Environmental exposure to endocrine-disrupting chemicals (EDCs) is one cause of premature ovarian failure (POF). Hexavalent chromium (CrVI) is a heavy metal EDC widely used in more than 50 industries, including chrome plating, welding, wood processing, and tanneries. Recent data from U.S. Environmental Protection Agency indicate increased levels of Cr in drinking water from several American cities, which potentially predispose residents to various health problems. Recently, we demonstrated that gestational exposure to CrVI caused POF in F1 offspring. The current study was performed to identify the molecular mechanism behind CrVI-induced POF. Pregnant rats were treated with 25 ppm of potassium dichromate from Gestational Day (GD) 9.5 to GD 14.5 through drinking water, and the fetuses were exposed to CrVI through transplacental transfer. Ovaries were removed from the fetuses or pups on Embryonic Day (ED) 15.5, ED 17.5, Postnatal Day (PND) 1, PND 4, or PND 25, and various analyses were performed. Results showed that gestational exposure to CrVI: 1) increased germ cell/oocyte apoptosis and advanced germ cell nest (GCN) breakdown; 2) increased X-prolyl aminopeptidase (Xpnpep) 2, a POF marker in humans, during GCN breakdown; 3) decreased Xpnpep2 during postnatal follicle development; and 4) increased colocalization of Xpnpep2 with Col3 and Col4. We also found that Xpnpep2 inversely regulated the expression of Col1, Col3, and Col4 in all the developmental stages studied. Thus, CrVI advanced GCN breakdown and increased follicle atresia in F1 female progeny by targeting Xpnpep2.

Genetics of female infertility due to anomalies of the ovary and mullerian ducts

Genetic factors are pivotal in reproductive development and subsequent reproductive processes. If disturbed, infertility can occur. In the female, genetic factors affecting the ovary and the uterus are not uncommon causes of infertility. Terminal deletions on the X long arm and X short arm and X chromosomal mosaicism have long been accepted as causes of premature ovarian failure (POF). Responsible genes on the X have not yet elucidated. Attractive candidate genes for POF also exist on autosomes, and in over a dozen genes molecular perturbations are documented in non-syndromic POF. The most common single-gene cause of POF is premutation carriers for FMR1 (fragile X syndrome). As other candidate genes and additional ethnic groups are interrogated, the proportion of POF cases due to single-gene mutation will increase. Among uterine anomalies, incomplete mullerian fusion is most common. Increased recurrence risks for first-degree relatives confirm a role for genetic factors; interrogation of candidate genes is under way.

A clinical research integration special program (CRISP) for young women with primary ovarian insufficiency

Large-scale medical sequencing provides a focal point around which to reorganize health care and health care research. Mobile health (mHealth) is also currently undergoing explosive growth and could be another innovation that will change the face of future health care. We are employing primary ovarian insufficiency (POI) as a model rare condition to explore the intersection of these potentials. As both sequencing capabilities and our ability to intepret this information improve, sequencing for medical purposes will play an increasing role in health care beyond basic research: it will help guide the delivery of care to patients. POI is a serious chronic disorder and syndrome characterized by hypergonadotrophic hypogonadism before the age of 40 years and most commonly presents with amenorrhea. It may have adverse health effects that become fully evident years after the initial diagnosis. The condition is most commonly viewed as one of infertility, however, it may also be associated with adverse long-term outcomes related to inadequate bone mineral density, increased risk of cardiovascular disease, adrenal insufficiency, hypothyroidism and, if pregnancy ensues, having a child with Fragile X Syndrome. There may also be adverse outcomes related to increased rates of anxiety and depression. POI is also a rare disease, and accordingly, presents special challenges. Too often advances in research are not effectively integrated into community care at the point of service for those with rare diseases. There is a need to connect community health providers in real time with investigators who have the requisite knowledge and expertise to help manage the rare disease and to conduct ongoing research. Here we review the pathophysiology and management of POI and propose the development of an international Clinical Research Integration Special Program (CRISP) for the condition.