Geneetiline varieeruvus kui naisepoolse viljatuse eelsoodumuse mõjutaja ja võimalike uute biomarkerite allikas

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Üks tark mees on öelnud, et lapse saamine on üks ebatõenäoline protsess, ja arvestades seda, kui paljud paarid on viljatusega hädas, oli tal ilmselt õigus. Eestis on enamik naisepoolse viljatuse juhtudest tingitud peamiselt infektsioonide põhjustatud munajuhaviljatusest ja polütsüstiliste munasarjade sündroomist (PCOS), millele on iseloomulik meessuguhormoonide kõrgenenud tase ja insuliinresistentsus. Kunstlik viljastamine võib aidata sellistel juhtudel järglasi saada, kuid kahjuks on ravi tulemuslikkus ~30% ja sõltub suuresti sellest, kuidas munasarjad reageerivad ravi käigus kasutatavatele hormoonidele. Viljatuse molekulaarseid tagamaid on aastate jooksul palju uuritud ja on jõutud järeldusele, et individuaalne geneetiline varieeruvus mängib selle tekkes kindlasti olulist rolli. Geneetilise varieeruvuse uuringud võimaldavad leida ka biomarkereid, mis sobiksid reproduktiivpotentsiaali ja ehk isegi viljatusravi tulemuslikkuse ennustamiseks. Käesoleva töö üldine eesmärk oli hinnata seoseid erinevate geneetiliste variatsioonide ja PCOS-i ning munajuhaviljatuse vahel. Lisaks uurisime mitmeid menopausi algusajaga või munasarja funktsiooniga seotud geneetilisi variante, mis võiksid olla seotud reproduktiivpotentsiaali ja viljatusravi tulemuslikkuse parameetritega. Selle jaoks koguti tervete ja viljakusprobleemidega naiste DNA proovid ning analüüsiti 47 geneetilise variandi seost huvipakkuvate diagnooside ja kliiniliste tunnustega. Et teha kindlaks, kui suur osa munajuhaviljatuse juhtudest on tingitud urogenitaalsest klamüüdiainfektsioonist, määrati munajuhaviljatusega naiste vereseerumist klamüüdia-vastaste antikehade esinemine. Leidsime, et ~50% kõigist munajuhaviljatuse juhtudest võivad olla tingitud eelnevast klamüüdiainfektsioonist ja näitasime, et immuunvastust mõjutav mannoosi siduva lektiini geeni varieeruvus on ilmselt seotud munajuhaviljatuse geneetilise eelsoodumusega. Insuliini ja androgeeni retseptori geenide varieeruvus ei olnud seotud PCOS-iga. Lisaks näitasime, et menopausi algusaega mõjutavad geenivariandid on seotud munasarja funktsiooni ja viljatusravi tulemuslikkuse parameetritega, ja tulevikus võiks neid kombineerituna kliiniliste andmetega kaaluda võimalike biomarkeritena. Antud töö andis uut teavet naise viljakuse ja viljatuse geneetika kohta, kuid ühtlasi rõhutas edasiste uuringute vajalikkust.A wise man once said that the reproduction of mankind is a great marvel and mystery, and he was absolutely right, considering how many couples actually tackle with infertility. In Estonia, the majority of female infertility cases are due to tubal infertility (TFI) that is mostly caused by sexually transmitted infections, and polycystic ovary syndrome (PCOS), which is an endocrine disorder characterised by androgen excess and insulin resistance. In vitro fertilisation can help achieve pregnancy in these cases, but unfortunately the pregnancy rate per treatment cycle is only 30% and depends greatly on how the ovaries respond to the treatment. Over the years, great effort has been directed towards elucidating the molecular mechanisms behind the conditions causing infertility and it has been concluded that individual genetic variation is definitely one of the factors to blame. The studies of individual genetic variation form a good basis for finding biomarkers to predict natural reproductive function and perhaps even infertility treatment success. The general objective of the current thesis was to assess the associations between PCOS, TFI and selected candidate genes. In addition, several genetic variants that could be related to ovarian function and infertility treatment parameters were evaluated. Thus, DNA samples were collected from healthy women and infertile women and 47 genetic variants were studied in association with diagnoses of interest and different clinical parameters. In addition, to determine how many TFI cases are caused by a chlamydia infection, the prevalence of chlamydia-specific antibodies was measured in the blood sera of women with TFI. As a result, we found that ~50% of all TFI cases in Estonia might be caused by a previous chlamydia infection and identified genetic variants in the mannose binding lectin gene that modulate immune response and may be associated with susceptibility to TFI. No associations were found between selected variants in genes for insulin and androgen receptor and PCOS. However, we showed that genetic variants related to menopause timing are associated with ovarian function and infertility treatment parameters and could be considered as biomarker candidates if combined with clinical data. In conclusion, this study gave new knowledge about the genetics of female reproduction, but also highlighted the need for further research

Whole exome sequencing of benign pulmonary metastasizing leiomyoma reveals mutation in the BMP8B gene

Background: Benign metastasizing leiomyoma (BML) is an orphan neoplasm commonly characterized by pulmonary metastases consisting of smooth muscle cells. Patients with BML have usually a current or previous uterine leiomyoma, which is therefore suggested to be the most probable source of this tumour. The purpose of this case report was to determine the possible genetic grounds for pulmonary BML. Case presentation: We present a case report in an asymptomatic 44-year-old female patient, who has developed uterine leiomyoma with subsequent pulmonary BML. Whole exome sequencing (WES) was used to detect somatic mutations in BML lesion. Somatic single nucleotide mutations were identified by comparing the WES data between the pulmonary metastasis and blood sample of the same BML patient. One heterozygous somatic mutation was selected for validation by Sanger sequencing. Clonality of the pulmonary metastasis and uterine leiomyoma was assessed by X-chromosome inactivation assay. Conclusions: We describe a potentially deleterious somatic heterozygous mutation in bone morphogenetic protein 8B (BMP8B) gene (c.1139A > G, Tyr380Cys) that was identified in the pulmonary metastasis and was absent from blood and uterine leiomyoma, and may play a facilitating role in the metastasizing of BML. The clonality assay confirmed a skewed pattern of X-chromosome inactivation, suggesting monoclonal origin of the pulmonary metastases.Peer reviewe

DNA methylation changes in endometrium and correlation with gene expression during the transition from pre-receptive to receptive phase

The inner uterine lining (endometrium) is a unique tissue going through remarkable changes each menstrual cycle. Endometrium has its characteristic DNA methylation profile, although not much is known about the endometrial methylome changes throughout the menstrual cycle. The impact of methylome changes on gene expression and thereby on the function of the tissue, including establishing receptivity to implanting embryo, is also unclear. Therefore, this study used genome-wide technologies to characterize the methylome and the correlation between DNA methylation and gene expression in endometrial biopsies collected from 17 healthy fertile-aged women from pre-receptive and receptive phase within one menstrual cycle. Our study showed that the overall methylome remains relatively stable during this stage of the menstrual cycle, with small-scale changes affecting 5% of the studied CpG sites (22,272 out of studied 437,022 CpGs, FDR <0.05). Of differentially methylated CpG sites with the largest absolute changes in methylation level, approximately 30% correlated with gene expression measured by RNA sequencing, with negative correlations being more common in 5 ' UTR and positive correlations in the gene 'Body' region. According to our results, extracellular matrix organization and immune response are the pathways most affected by methylation changes during the transition from pre-receptive to receptive phase.Peer reviewe

Meta-signature of human endometrial receptivity : a meta-analysis and validation study of transcriptomic biomarkers

Previous transcriptome studies of the human endometrium have revealed hundreds of simultaneously up-and down-regulated genes that are involved in endometrial receptivity. However, the overlap between the studies is relatively small, and we are still searching for potential diagnostic biomarkers. Here we perform a meta-analysis of endometrial-receptivity associated genes on 164 endometrial samples (76 from 'pre-receptive' and 88 from mid-secretory, 'receptive' phase endometria) using a robust rank aggregation (RRA) method, followed by enrichment analysis, and regulatory microRNA prediction. We identify a meta-signature of endometrial receptivity involving 57 mRNA genes as putative receptivity markers, where 39 of these we confirm experimentally using RNA-sequencing method in two separate datasets. The meta-signature genes highlight the importance of immune responses, the complement cascade pathway and the involvement of exosomes in mid-secretory endometrial functions. Bioinformatic prediction identifies 348 microRNAs that could regulate 30 endometrial-receptivity associated genes, and we confirm experimentally the decreased expression of 19 microRNAs with 11 corresponding up-regulated meta-signature genes in our validation experiments. The 57 identified meta-signature genes and involved pathways, together with their regulatory microRNAs could serve as promising and sought-after biomarkers of endometrial receptivity, fertility and infertility.Peer reviewe

Advances in the Molecular Pathophysiology, Genetics, and Treatment of Primary Ovarian Insufficiency

Primary ovarian insufficiency (POI) affects similar to 1% of women before 40 years of age. The recent leap in genetic knowledge obtained by next generation sequencing (NGS) together with animal models has further elucidated its molecular pathogenesis, identifying novel genes/pathways. Mutations of > 60 genes emphasize high genetic heterogeneity. Genome-wide association studies have revealed a shared genetic background between POI and reproductive aging. NGS will provide a genetic diagnosis leading to genetic/therapeutic counseling: first, defects in meiosis or DNA repair genes may predispose to tumors; and second, specific gene defects may predict the risk of rapid loss of a persistent ovarian reserve, an important determinant in fertility preservation. Indeed, a recent innovative treatment of POI by in vitro activation of dormant follicles proved to be successful.Peer reviewe

Identification of Common Genetic Variants Influencing Spontaneous Dizygotic Twinning and Female Fertility.

Spontaneous dizygotic (DZ) twinning occurs in 1%-4% of women, with familial clustering and unknown physiological pathways and genetic origin. DZ twinning might index increased fertility and has distinct health implications for mother and child. We performed a GWAS in 1,980 mothers of spontaneous DZ twins and 12,953 control subjects. Findings were replicated in a large Icelandic cohort and tested for association across a broad range of fertility traits in women. Two SNPs were identified (rs11031006 near FSHB, p = 1.54 × 10(-9), and rs17293443 in SMAD3, p = 1.57 × 10(-8)) and replicated (p = 3 × 10(-3) and p = 1.44 × 10(-4), respectively). Based on ∼90,000 births in Iceland, the risk of a mother delivering twins increased by 18% for each copy of allele rs11031006-G and 9% for rs17293443-C. A higher polygenic risk score (PRS) for DZ twinning, calculated based on the results of the DZ twinning GWAS, was significantly associated with DZ twinning in Iceland (p = 0.001). A higher PRS was also associated with having children (p = 0.01), greater lifetime parity (p = 0.03), and earlier age at first child (p = 0.02). Allele rs11031006-G was associated with higher serum FSH levels, earlier age at menarche, earlier age at first child, higher lifetime parity, lower PCOS risk, and earlier age at menopause. Conversely, rs17293443-C was associated with later age at last child. We identified robust genetic risk variants for DZ twinning: one near FSHB and a second within SMAD3, the product of which plays an important role in gonadal responsiveness to FSH. These loci contribute to crucial aspects of reproductive capacity and health.Support for the Netherlands Twin Register was obtained from the Netherlands Organization for Scientific Research (NWO) and The Netherlands Organization for Health Research and Development (ZonMW) grants, 904-61-193,480-04-004, 400-05-717, Addiction-31160008, 911-09-032, Biobanking and Biomolecular Resources Research Infrastructure (BBMRI –NL, 184.021.007); Royal Netherlands Academy of Science Professor Award (PAH/6635) to DIB; European Research Council (ERC-230374 and ERC-284167); Rutgers University Cell and DNA Repository (NIMH U24 MH068457-06), the Avera Institute, Sioux Falls, South Dakota (USA) and the National Institutes of Health (NIH R01 HD042157-01A1). Part of the genotyping was funded by the Genetic Association Information Network (GAIN) of the Foundation for the National Institutes of Health and Grand Opportunity grants 1RC2 MH089951). We acknowledge support from VU Amsterdam and the Institute for Health and Care Research (EMGO+). The Berghofer Medical Research Institute (QIMR) study was supported by grants from the National Health and Medical Research Council (NHMRC) of Australia (241944, 339462, 389927, 389875, 389891, 389892, 389938, 443036, 442915, 442981, 496610, 496739, 552485, 552498, 1050208, 1075175). Dale R. Nyholt was supported by the Australian Research Council (ARC) Future Fellowship (FT0991022), NHMRC Research Fellowship (APP0613674) Schemes and by the Visiting Professors Programme (VPP) of the Royal Netherlands Academy of Arts and Sciences (KNAW). Allan F. McRae was supported by an NRMRC Career Development Fellowship (APP1083656). Grant W. Montgomery was supported by NIH grant (HD042157, a collaborative study of the genetics of DZ twinning) and NHMRC Fellowship (GNT1078399). The Minnesota Center for Twin and Family Research (MCTFR) was supported in part by USPHS Grants from the National Institute on Alcohol Abuse and Alcoholism (AA09367 and AA11886), and the National Institute on Drug Abuse (DA05147, DA13240, and DA024417). We would like to thank also 23andMe's consented research participants for contributing data on age at menarche for the FSHB gene locus and the Twinning Gwas Consortium (TGC). Co-authors from: Finland (Anu Loukola, Juho Wedenoja, Emmi Tikkanen, Beenish Qaiser), Sweden (Nancy Pedersen, Andrea Ganna), United kingdom King's College London (Department of Twin Research & Genetic Epidemiology: Pirro Hysi, Massimo Mangino), Institute of Psychiatry, Psychology & Neuroscience, Medical Research Council Social, Genetic and Developmental Psychiatry Centre (Eva Krapohl, Andrew McMillan).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ajhg.2016.03.00

Challenges in endometriosis miRNA studies - From tissue heterogeneity to disease specific miRNAs

In order to uncover miRNA changes in endometriosis pathogenesis, both endometriotic lesions and endometrial biopsies, as well as stromal and epithelial cells isolated from these tissues have been investigated and a large number of dysregulated miRNAs have been reported. However, the concordance between the result of different studies has remained small. One potential explanation for limited overlap between the proposed disease-related miRNAs could be the heterogeneity in tissue composition, as some studies have compared highly heterogeneous whole-lesion biopsies with endometrial tissue, some have compared the endometrium from patients and controls, and some have used pure cell fractions isolated from lesions and endometrium. This review focuses on the results of published miRNA studies in endometriosis to reveal the potential impact of tissue heterogeneity on the discovery of disease-specific miRNA alterations in endometriosis. Additionally, functional studies that explore the roles of endometriosis-involved miRNAs are discussed.Peer reviewe

Ovarian Physiology and GWAS : Biobanks, Biology, and Beyond

Ovarian function is central to female fertility, and several genome-wide association studies (GWAS) have been carried out to elucidate the genetic background of traits and disorders that reflect and affect ovarian physiology. While GWAS have been successful in reporting numerous genetic associations and highlighting involved pathways relevant to reproductive aging, for ovarian disorders, such as premature ovarian insufficiency and polycystic ovary syndrome, research has lagged behind due to insufficient study sample size. Novel approaches to study design and analysis methods that help to fit GWAS findings into biological context will improve our knowledge about genetics governing ovarian function in fertility and disease, and provide input for clinical tools and better patient management.Peer reviewe

Single-cell transcriptome analysis of endometrial tissue

STUDY QUESTION: How can we study the full transcriptome of endometrial stromal and epithelial cells at the single-cell level? SUMMARY ANSWER: By compiling and developing novel analytical tools for biopsy, tissue cryopreservation and disaggregation, single-cell sorting, library preparation, RNA sequencing (RNA-seq) and statistical data analysis. WHAT IS KNOWN ALREADY: Although single-cell transcriptome analyses from various biopsied tissues have been published recently, corresponding protocols for human endometrium have not been described. STUDY DESIGN, SIZE, DURATION: The frozen-thawed endometrial biopsies were fluorescence-activated cell sorted (FACS) to distinguish CD13-positive stromal and CD9-positive epithelial cells and single-cell transcriptome analysis performed from biopsied tissues without culturing the cells. We studied gene transcription, applying a modern and efficient RNA-seq protocol. In parallel, endometrial stromal cells were cultured and global expression profiles were compared with uncultured cells. PARTICIPANTS/MATERIALS, SETTING, METHODS: For method validation, we used two endometrial biopsies, one from mid-secretory phase (Day 21, LH+8) and another from late-secretory phase (Day 25). The samples underwent single-cell FACS sorting, single-cell RNA-seq library preparation and Illumina sequencing. MAIN RESULTS AND THE ROLE OF CHANCE: Here we present a complete pipeline for single-cell gene-expression studies, from clinical sampling to statistical data analysis. Tissue manipulation, starting from disaggregation and cell-type-specific labelling and ending with single-cell automated sorting, is managed within 90 min at low temperature to minimize changes in the gene expression profile. The single living stromal and epithelial cells were sorted using CD13- and CD9-specific antibodies, respectively. Of the 8622 detected genes, 2661 were more active in cultured stromal cells than in biopsy cells. In the comparison of biopsy versus cultured cells, 5603 commonly expressed genes were detected, with 241 significantly differentially expressed genes. Of these, 231 genes were up- and 10 down-regulated in cultured cells, respectively. In addition, we performed a gene ontology analysis of the differentially expressed genes and found that these genes are mainly related to cell cycle, translational processes and metabolism. LIMITATIONS, REASONS FOR CAUTION: Although CD9-positive single epithelial cells sorting was successfully established in our laboratory, the amount of transcriptome data per individual epithelial cell was low, complicating further analysis. This step most likely failed due to the high dose of RNases that are released by the cells' natural processes, or due to rapid turnaround time or the apoptotic conditions in freezing- or single-cell solutions. Since only the cells from the late-secretory phase were subject to more focused analysis, further studies including larger sample size from the different time-points of the natural menstrual cycle are needed. The methodology also needs further optimization to examine different cell types at high quality. WIDER IMPLICATIONS OF THE FINDINGS: The symbiosis between clinical biopsy and the sophisticated laboratory and bioinformatic protocols described here brings together clinical diagnostic needs and modern laboratory and bioinformatic solutions, enabling us to implement a precise analytical toolbox for studying the endometrial tissue even at the single-cell level.Peer reviewe