Search Results - EGA European Genome-Phenome Archive

Parkinson's Disease Cognitive Genetics Consortium (PDCGC) Stage I, NeuroX Dataset

Cognitive impairment is a common and disabling problem in Parkinson's disease (PD). Identification of genetic variants that influence the presence or severity of cognitive deficits in PD might provide a clearer understanding of the pathophysiology underlying this important nonmotor feature. We are presently undertaking a large-scale, two-stage study designed to identify genetic risk factors for cognitive impairment in PD. The study population is divided into a discovery (Stage I) and a validation (Stage II) sample of patients enrolled in the PD Cognitive Genetics Consortium (PDCGC). Each patient has undergone a detailed neurological evaluation and cognitive testing. Clinical and genetic data for the project are stored and managed at the Coordinating Center at the University of Washington and VA Puget Sound Health Care System in Seattle. Stage I of the project is now complete; 1,219 PD patients were genotyped for 249,336 variants using the NeuroX array. Participants underwent assessments of learning and memory (Hopkins Verbal Learning Test-Revised [HVLT-R]), working memory/executive function (Letter-Number Sequencing and Trail Making Test [TMT] A and B), language processing (semantic and phonemic verbal fluency), visuospatial abilities (Benton Judgment of Line Orientation [JoLO]), and global cognitive function (Montreal Cognitive Assessment). We excluded individuals who were of non-European ancestry, failed genotyping, were missing data for one or more covariates, were related to another participant in the cohort, or failed to complete at least half of the cognitive tests. After these quality control measures were implemented, 1,105 participants remained and were included in all subsequent analyses. For common variants we used linear regression to test for association between genotype and cognitive performance with adjustment for important covariates. Rare variants were analyzed using the optimal unified sequence kernel association test. The significance threshold was defined as a false discovery rate corrected P-value (PFDR) of 0.05. Eighteen common variants in 13 genomic regions exceeded the significance threshold for one of the cognitive tests. These included GBA rs2230288 (E326K; PFDR = 2.7 x 10-4) for JoLO, PARP4 rs9318600 (PFDR = 0.006) and rs9581094 (PFDR = 0.006) for HVLT-R total recall, and MTCL1 rs34877994 (PFDR = 0.01) for TMT B-A. Analysis of rare variants did not yield any significant gene regions. We have conducted the first large-scale PD cognitive genetics analysis and nominated several new putative susceptibility genes for cognitive impairment in PD. These results will require replication in independent PD cohorts, and efforts to validate the findings in PDCGC Stage II are in progress.

Study phs001664

Mucociliary Clearance Consortium (MCC) Rare Genetic Disorders of the Airways: Cross-section Comparison of Clinical Features, and Development of Novel Screening and Genetic Test

We have established a consortium of 7 geographically-dispersed clinical research sites that are designed to study rare diseases of the airways, which involve defects in clearance of mucus secretions from the airways (defective "mucociliary clearance"). These sites will collaborate in diagnostic, genetic, and other studies in patients with impairments of mucociliary clearance, including primary ciliary dyskinesia (PCD), variant cystic fibrosis (CF), and pseudohypoaldosteronism (PHA). These disorders reflect genetic defects in airway host-defense, and typically result in chronic infection of the airways. Patients with these disorders of the conducting airways and sinuses have delayed (or incorrect) diagnoses, because diagnostic tests are not readily available. These patients may also have sub-optimal management of their clinical disease, because the cause of these disorders is not well-defined, and treatment regimens are usually not driven by evidence-based medicine. This current protocol is designed to employ a systematic approach to the diagnostic evaluation of these patients with chronic airways disease, which will yield precise diagnoses in individual patients, and will be associated with development of better diagnostic techniques, including genetic testing. In addition, we will compare/contrast clinical features (phenotype) across these disorders. A rigorous cross-sectional comparison of the clinical features will provide better understanding of the clinical disease of these disorders; in turn, this will lead not only to a better standard of clinical care, but will also assist in the identification of novel therapeutic approaches. The patient population for these studies includes individuals carrying a tentative diagnosis of the three disorders (PCD, variant CF or PHA), plus individuals suspected to have one of these disorders, but with inadequate or inconclusive diagnostic tests. Individuals in this latter category must have a preliminary clinical evaluation to evaluate for other more common disorders that may have similar manifestations including classical CF, immunodeficiency, asthma, and severe gastroesophageal reflux. We have an informal agreement with a network of pulmonologists across the United States to perform clinically-indicated (not research) preliminary clinical testing, if not directly available to patients who inquire about these studies. Blood will be collected for DNA to test for genetic mutations. The blood samples will be processed to establish a cell line (lymphocyte transformation) for a source of DNA for future genetic studies, in participants with disease. For participants unable to provide a blood sample, a buccal sample will be obtained for DNA.

Study phs000595

Tumor transcriptome profiling from the OAK and POPLAR randomized clinical trials of atezolizumab in 2L NSCLC

This dataset includes full tumor transcriptomes from 891 advanced NSCLC tumors. These data originate from pre-treatment samples from two large randomized clinical trials for second-line non-small cell lung cancer (POPLAR and OAK). The patients in these trials were treated with either the PD-L1 inhibitor atezolizumab or chemotherapy.

Dataset EGAD00001007703

Detection of Colorectal Cancer Susceptibility Loci Using Genome-Wide Sequencing

The Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) is a collaborative effort comprised of a coordinating center and scientific researchers from well-characterized cohort and case-control studies. This international consortium aims to accelerate the discovery of common and rare genetic risk variants for colorectal cancer by conducting large-scale meta-analyses of existing and newly generated genome-wide association study (GWAS) data, whole genome sequencing, replicating and fine-mapping of genetic discoveries, and investigating how genetic risk variants are modified by environmental risk factors. To expand these efforts, we assembled case-control sets or nested case-control sets from 6 different North American or European studies. Summary descriptions and study participant inclusions/exclusion criteria for each of these studies are detailed below. Cancer Prevention Study II (CPS II): The CPS II Nutrition cohort is a prospective study of cancer incidence and mortality in the United States, established in 1992 and described in detail elsewhere (Calle et al., 2002 PMID:12015775; Campbell et al., 2014 PMID:25472679). At enrollment, participants completed a mailed self-administered questionnaire including information on demographic, medical, diet, and lifestyle factors. Follow-up questionnaires to update exposure information and to ascertain newly diagnosed cancers were sent biennially starting in 1997. Reported cancers were verified through medical records, state cancer registry linkage, or death certificates. The Emory University Institutional Review Board approves all aspects of the CPS II Nutrition Cohort. We restricted to samples that had blood DNA source. Controls were matched to cases in a case/control ratio of 2:1 on reference year and sex. Darmkrebs: Chancen der Verhütung durch Screening (DACHS): This German study was initiated as a large population-based case-control study in 2003 in the Rhine-Neckar-Odenwald region (southwest region of Germany) to assess the potential of endoscopic screening for reduction of colorectal cancer risk and to investigate etiologic determinants of disease, particularly lifestyle/environmental factors and genetic factors. Cases with a first diagnosis of invasive colorectal cancer (International Classification of Diseases 10 codes C18-C20) who were at least 30 years of age (no upper age limit), German speaking, a resident in the study region, and mentally and physically able to participate in a one-hour interview, were recruited by their treating physicians either in the hospital a few days after surgery, or by mail after discharge from the hospital. Cases were confirmed based on histologic reports and hospital discharge letters following diagnosis of colorectal cancer. All hospitals treating colorectal cancer patients in the study region participated. Based on estimates from population-based cancer registries, more than 50% of all potentially eligible patients with incident colorectal cancer in the study region were included. Community-based controls were randomly selected from population registries, employing frequency matching with respect to age (5-year groups), sex, and county of residence. Controls with a history of colorectal cancer were excluded. Controls were contacted by mail and follow-up calls. The participation rate was 51%. During an in-person interview, data were collected on demographics, medical history, family history of CRC, and various life-style factors, as were blood and mouthwash samples. Routine formalin-fixed, paraffin-embedded (FFPE) tumor samples from the patients enrolled were requested from the pathology institutes and used for tumor tissue analyses. This analysis includes participants with blood source DNA that were recruited up to 2010 in this ongoing study. Controls were matched to cases on reference age and sex in a case/control ratio of 2:1. Health Professionals Follow-up Study (HPFS): A parallel prospective study to the NHS (Nurses' Health Study). The HPFS cohort comprised 51,529 men aged 40-75 who, in 1986, responded to a mailed questionnaire (Rimm et al., 1990 PMID:2090285). Participants provided information on health related exposures, including current and past smoking history, age, weight, height, diet, physical activity, aspirin use, and family history of colorectal cancer. Colorectal cancer and other outcomes were reported by participants or next-of-kin and were followed up through review of the medical and pathology record by physicians. Overall, more than 97% of self-reported colorectal cancers were confirmed by medical record review. Information was abstracted on histology and primary location. Incident cases were defined as those occurring after the subject provided the blood sample. Prevalent cases were defined as those occurring after enrollment in the study but before the subject provided the blood sample. Follow-up evaluation has been excellent, with 94% of the men responding to date. Colorectal cancer cases were ascertained through January 1, 2008. In 1993-1995, 18,825 men in the HPFS mailed blood samples by overnight courier, which were aliquoted into buffy coat and stored in liquid nitrogen. In 2001-2004, 13,956 men in the HPFS who had not provided a blood sample previously mailed in a swish-and-spit sample of buccal cells. Incident cases were defined as those occurring after the subject provided a blood or buccal sample. Prevalent cases were defined as those occurring after enrollment in the study in 1986, but before the subject provided either a blood or buccal sample. Participants with histories of cancer (except nonmelanoma skin cancer), ulcerative colitis, or familial polyposis, case-control sets were excluded. Control participants were required to be free of invasive colorectal cancer and non-invasive (stage 0 in situ) colorectal cancer. For this study, only European ancestry participants with blood source DNA and incident colorectal cancer cases were eligible for selection. Since enrollment year and sex matched exactly, controls were randomly selected in a case/control ratio of 2:1. Nurses Health Study (NHS): The NHS cohort began in 1976 when 121,700 married female registered nurses age 30-55 years returned the initial questionnaire that ascertained a variety of important health-related exposures (Belanger et al., 1978 PMID:248266). Since 1976, follow-up questionnaires have been mailed every 2 years. Colorectal cancer and other outcomes were reported by participants or next-of-kin and followed up through review of the medical and pathology record by physicians. Overall, more than 97% of self-reported colorectal cancers were confirmed by medical-record review. Information was abstracted on histology and primary location. The rate of follow-up evaluation has been high: as a proportion of the total possible follow-up time, follow-up evaluation has been more than 92%. Colorectal cancer cases were ascertained through June 1, 2008. In 1989-1990, 32,826 women in NHS I mailed blood samples by overnight courier, which were aliquoted into buffy coat and stored in liquid nitrogen. In 2001-2004, 29,684 women in NHS I who did not previously provide a blood sample mailed a swish-and-spit sample of buccal cells. Incident cases were defined as those occurring after the subject provided a blood or buccal sample. Prevalent cases were defined as those occurring after enrollment in the study in 1976 but before the subject provided either a blood or buccal sample. Participants with histories of cancer (except nonmelanoma skin cancer), ulcerative colitis, or familial polyposis, case-control sets were excluded. For this study, only European ancestry participants with blood source DNA and incident colorectal cancer cases were eligible for selection. Since enrollment year and sex matched exactly, controls were randomly selected in a case/control ratio of 2:1. Prostate, Lung, Colorectal and Ovarian Cancer Screening Trail (PLCO): PLCO enrolled 154,934 participants (men and women, aged between 55 and 74 years) at ten centers into a large, randomized, two-arm trial to determine the effectiveness of screening to reduce cancer mortality. Sequential blood samples were collected from participants assigned to the screening arm. Participation was 93% at the baseline blood draw. White colorectal cancer cases with a family history of colorectal cancer (no history of ulcerative colitis, Crohn's Disease, diverticulitis, Gardner's syndrome, Familial Polyposis) and successful genotyping from previous Peters GWAS were selected for this project. Controls were matched to cases on reference age and sex in a case/control ratio of 2:1. Women's Health Initiative (WHI): WHI is a long-term national health study that has focused on strategies for preventing heart disease, breast and colorectal cancer, and osteoporotic fractures in postmenopausal women. The original WHI study included 161,808 postmenopausal women enrolled between 1993 and 1998. The Fred Hutchinson Cancer Research Center in Seattle, WA serves as the WHI Clinical Coordinating Center for data collection, management, and analysis of the WHI. The WHI has two major parts: a partial factorial randomized Clinical Trial (CT) and an Observational Study (OS); both were conducted at 40 Clinical Centers nationwide. The CT enrolled 68,132 postmenopausal women between the ages of 50-79 into trials testing three prevention strategies. If eligible, women could choose to enroll in one, two, or all three of the trial components. The components are: Hormone Therapy Trials (HT): This double-blind component examined the effects of combined hormones or estrogen alone on the prevention of coronary heart disease and osteoporotic fractures, and associated risk for breast cancer. Women participating in this component with an intact uterus were randomized to estrogen plus progestin (conjugated equine estrogens [CEE], 0.625 mg/d plus medroxyprogesterone acetate [MPA] 2.5 mg/d) or a matching placebo. Women with prior hysterectomy were randomized to CEE or placebo. Both trials were stopped early, in July 2002 and March 2004, respectively, based on adverse effects. All HT participants continued to be followed without intervention until close-out. Dietary Modification Trial (DM): The Dietary Modification component evaluated the effect of a low-fat and high fruit, vegetable and grain diet on the prevention of breast and colorectal cancers and coronary heart disease. Study participants were randomized to either their usual eating pattern or a low-fat dietary pattern. Calcium/Vitamin D Trial (CaD): This double-blind component began 1 to 2 years after a woman joined one or both of the other clinical trial components. It evaluated the effect of calcium and vitamin D supplementation on the prevention of osteoporotic fractures and colorectal cancer. Women in this component were randomized to calcium (1000 mg/d) and vitamin D (400 IU/d) supplements or a matching placebo. The Observational Study (OS) examines the relationship between lifestyle, environmental, medical and molecular risk factors and specific measures of health or disease outcomes. This component involves tracking the medical history and health habits of 93,676 women not participating in the CT. Recruitment for the observational study was completed in 1998 and participants were followed annually for 8 to 12 years. All centrally confirmed White cases of invasive colorectal cancer, or death from colorectal cancer were selected as potential cases from the March, 2011 database. Case priory lists are: 1) have positive family history of colorectal cancer; 2) randomly select cases until we get a total of n=800 cases. Control participants were required to be White, free of invasive colorectal cancer and non-invasive (stage 0 in situ) colorectal cancer. Centrally denied cases of colorectal cancer were not allowed into the control pool. Case and control participants were subject to the following exclusion criteria: (1) had prior history of colorectal cancer at baseline; (2) had no available DNA (DNA searching as Nov 15, 2012); (3) cannot be deposited to dbGaP; (4) lost to follow-up after enrollment; (5) selected for WHI study M26 Phase II. Controls were matched to cases in a case/control ratio of 2:1. In order to get 2 cases with 1 control, cases were grouped by enrollment year (a total of 5 groups). For each year group, around 50% cases were selected to match controls. In total, 401 cases were selected to match controls. Matching was done on enrollment year, which was matched exactly. For additional information, see dbGaP: phs000200 and ClinicalTrials: NCT00000611.

Study phs001554

Disorders/Differences of Sex Development (DSD) Study Performed at UCLA in Collaboration with the DSD-Translational Research Network (DSD-TRN), with the Support of the Gabriella Miller Kids First Pediatric Research Program

The Gabriella Miller Kids First Pediatric Research Program (Kids First) is a trans-NIH effort initiated in response to the 2014 Gabriella Miller Kids First Research Act and supported by the NIH Common Fund. This program focuses on gene discovery in pediatric cancers and structural birth defects and the development of the Gabriella Miller Kids First Pediatric Data Resource (Kids First Data Resource). Both childhood cancers and structural birth defects are critical and costly conditions associated with substantial morbidity and mortality. Elucidating the underlying genetic etiology of these diseases has the potential to profoundly improve preventative measures, diagnostics, and therapeutic interventions. Whole Genome Sequence (WGS) and phenotypic data from this study are accessible through dbGaP and kidsfirstdrc.org, where other Kids First datasets can also be accessed. Disorders/Differences of Sex Development (DSD) are congenital conditions in which development of chromosomal, gonadal, or anatomic sex is atypical. DSD are chronic medical conditions collectively affecting ~1% of the population, frequently requiring life-long care by multiple specialists, and carrying a significant public health burden. Some are associated with life-threatening events, such as adrenal crises in Congenital Adrenal Hyperplasia (CAH). DSD are also associated with increased infertility, cancer, gender dysphoria risks, psychosocial distress and pervasive challenges to health-related quality of life (HRQoL) for patients and families. DSD are broadly classified into three categories: sex chromosome DSD, 46,XY DSD and 46,XX DSD, and further classified according to the type of gonad found in the patient (ovary, testis, ovotestis). We were able to increase significantly the diagnostic success for DSD using Whole Exome Sequencing (WES), with the identification of disease-causing and likely pathogenic variants in a third of a cohort of 46,XY patients. We have therefore proposed a shift in the diagnostic approach to DSD to use next-gen sequencing as a first-line clinical test, which could lead to faster and more accurate diagnosis, and orient further clinical management, limiting unnecessary, costly, and often invasive endocrine testing and imaging. However many remain unexplained (over half of the XY cases, a significant minority of XX cases, including most ovotesticular DSD, and most syndromic cases). In addition, the very large phenotypic variability in cases with known variants in the same gene is unexplained. We here propose to use Whole-Genome Sequencing (WGS), which dramatically improves upon exome sequencing, covering both coding and non-coding parts of the genome more uniformly, as an approach to not only improve diagnostic yield, but also to identify novel genes and regulatory elements involved in DSD.

Study phs001178

The Role of CDX2 in Controlling ABCB1 Expression and Chemosensitivity in Human Colon Cancer

This study reports the results of RNA sequencing (RNA-seq) experiments performed on two human colon cancer cell lines (HT-29, DLD-1) that were genetically engineered to achieve either the constitutive expression (in HT-29 cells) or the selective inactivation (in DLD-1 cells) of the transcription factor CDX2, a master regulator of embryonic gut development and a key regulator of multi-lineage differentiation in adult colon epithelial cells. Our previous studies had identified lack of CDX2 expression as a prognostic biomarker of poor prognosis and a predictive biomarker of benefit from adjuvant chemotherapy in Stage-II and Stage-III colon cancer patients (Dalerba et al., NEJM, 374:211-222, 2016; PMID: 26789870). The molecular basis of these associations, however, remained poorly understood. The present study was designed to identify which genes are under the transcriptional control of CDX2, in order to clarify their role in shaping colon cancer resistance to chemotherapy. Of the two lines included in this study, the first (HT-29) is CDX2-negative at baseline, and was infected with a lentivirus vector encoding for the cDNA of the human CDX2 gene under the control of a constitutive promoter (CMV). The second line (DLD-1) is CDX2-positive at baseline, and was infected with a series of lentivirus vectors encoding for CRISPR/Cas9 constructs designed to selectively inactivate the CDX2 gene. In both cases, infected cells were purified by fluorescence-activated cell sorting (FACS), based on the differential expression of a green fluorescent reporter (EGFP) that was also encoded by the lentivirus vectors, and transcribed in tandem with either the CDX2 cDNA (HT-29) or CRISPR/Cas9 gRNAs targeting CDX2 (DLD-1). The experiments were designed to include 3 experimental replicates per condition, and to compare the transcriptional profile of genetically engineered cells with that of autologous controls (i.e., HT-29 cells infected with an "empty" version of the same lentivirus vector used to over-express CDX2, DLD-1 cells engineered with a "non-targeting" CRISPR/Cas9 gRNA). In the specific case of DLD-1 cells engineered with CRIPSR-Cas9 constructs targeting CDX2, infected cells were sorted based on the differential expression of EGFP and then plated as single-cells, in order to sub-culture three isogenic clones, all of which were genetically sequenced to confirm bi-allelic knock-out of the CDX2 gene, and confirmed to lack CDX2 protein expression by Western blot. The results of our experiments demonstrate that, in human colon epithelial cells, CDX2 controls the expression of the ABCB1 efflux pump, by positively regulating the transcription of the corresponding gene.

Study phs002903

PanCuRx Translational Research Initiative

The goal of the PanCuRx TRI is to seek solutions to the high fatality rate of pancreatic adenocarcinoma (PDAC), the most common type of pancreatic cancer, by generating new knowledge about the genetics and biology of the disease, mechanisms of how tumours grow and tailored treatment options. PDAC is the fourth leading cause of cancer death in Canada and is expected to become the second-leading cause of cancer death within the next decade. The current five-year survival rate of eight per cent is the lowest of all epithelial cancers. There are major clinical challenges to treating the disease, including the fact that PDAC spreads to other parts of the body early so surgical removal of the tumour benefits few patients, that PDAC has proven relatively resistant to systemic therapies such as chemotherapy and that there has been limited benefit from the use of newer molecular targeted agents. The PanCuRx team has created the world’s first resource of tumour-purified PDAC whole genomes; more than 500 PDAC samples, with combined clinical annotation, have been successfully sequenced and analyzed at the Ontario Institute for Cancer research in Toronto. The resulting clinical genomic resource created from this data has led to multiple new findings that have established a framework to better understand PDAC biology and lays the foundation for new genomic approaches to better understanding the disease. The team also launched a clinical trial called COMPASS (Comprehensive Molecular Characterization of Advanced Ductal Pancreas Adenocarcinoma for Better Treatment Selection: A Prospective Study), which is recruiting patients with advanced PDAC (both locally advanced and metastatic) at The Princess Margaret Cancer Centre (PM) in Toronto. The study uses the molecular results from individual patient tumours to guide selection of better second line treatment on a case-by-case basis. The primary objective of the initial study was to assess the feasibility of collecting tumour materials from patients with advanced PDAC and delivering results within 56 days of biopsy. Having achieved this objective, the trial has expanded to other cancer centres across Canada. Pancreatic cancer is one of the most deadly forms of cancer and outcomes have not improved in four decades. The PanCuRx initiative is providing a better understanding of the disease and actively applying new knowledge to cancer patients through clinical trials. This knowledge will help to improve quality of life and prolong survival for pancreatic cancer patients worldwide.

Study EGAS00001002543

Examination of Engineered LINE-1 Integration Events in HeLa Cells

Long Interspsesed Element-1 (LINE1 or L1) encodes two proteins (ORF1p and ORF2p) required for its mobilization (i.e. retrotransposition) in the human genome. Human ORF2p, a 150kDa protein, has endonuclease (EN) and reverse transcriptase (RT) activities. L1 EN is classified as apurinic/apyrimidin-like endonuclease (APE) and is responsible for initiating target-site primer reverse transcription (TPRT) during the L1 retrotransposition cycle. During canonical TPRT, the L1 EN activity makes a single-strand endonucleolytic nick at a double-strand DNA target sequence in genomic DNA. The endonucleolytic nick is typically made at an L1 EN degnerate consensus cleavage sequence (5'-TTTT/A-3') exposing a free 3' hydroxy group that can be used as a primer by the ORF2p L1 RT activity to reverse transcribe the associated L1 RNA. Here, we characterized over 21,000 de novo engineered L1 retrotransposition events in HeLa cells to determine if L1 exhibits overt integration preferences in the human genome. Bru-seq of HeLa cells to determine actively transcribed regions of the genome was also performed. This Bru-seq data was used to determine if engineered L1 integration events preferentially integrate into transcribed regions of the genome, and to determine which strand during transcription may present itself as preferential during L1 retrotransposition.

Study phs001669

The Haplotype-Resolved Genome and Epigenome of the Aneuploid HeLa Cancer Cell Line

The genomic architecture of HeLa remains largely unexplored beyond its karyotype, partly because like many cancers, its extensive aneuploidy renders such analyses challenging. We carried out haplotype-resolved whole-genome sequencing of the HeLa CCL-2 strain, examined point- and indel-mutation variations, mapped copy-number variations and loss of heterozygosity regions, and phased variants across full chromosome arms. We also investigated variation and copy-number profiles for HeLa S3 and eight additional strains. We find that HeLa is relatively stable in terms of point variation, with few new mutations accumulating after early passaging. Haplotype resolution facilitated reconstruction of an amplified, highly rearranged region of chromosome 8q24.21 at which integration of the human papilloma virus type 18 (HPV-18) genome occurred and that is likely to be the event that initiated tumorigenesis. We combined these maps with RNA-seq and ENCODE Project data sets to phase the HeLa epigenome. This revealed strong, haplotype specific activation of the proto-oncogene MYC by the integrated HPV-18 genome approximately 500 kilobases upstream, and enabled global analyses of the relationship between gene dosage and expression. These data provide an extensively phased, high-quality reference genome for past and future experiments relying on HeLa, and demonstrate the value of haplotype resolution for characterizing cancer genomes and epigenomes. Reprinted from Adey et. al. 2013, Nature, with permission from Nature Publishing Group.

Study phs000642

In vitro reconstitution of epigenetic reprogramming in the human germ line

Epigenetic reprogramming resets parental epigenetic memories and differentiates primordial germ cells (PGCs) into mitotic pro-spermatogonia or oogonia, ensuring sexually dimorphic germ-cell development for totipotency. In vitro reconstitution of epigenetic reprogramming in humans remains a fundamental challenge. Here, we establish a robust strategy for inducing epigenetic reprogramming and differentiation of pluripotent stem cell (PSC)-derived human PGC-like cells (hPGCLCs) into mitotic pro-spermatogonia or oogonia, coupled with their extensive amplification (~>1010-fold). Strikingly, bone morphogenetic protein (BMP) signalling is a key driver of these processes: BMP-driven hPGCLC differentiation involves an attenuation of the mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) pathway and both de novo and maintenance DNA methyltransferase (DNMT) activities, likely promoting replication-coupled, passive DNA demethylation. On the other hand, hPGCLCs deficient in tens-eleven translocation (TET) 1, an active DNA demethylase abundant in human germ cells, differentiate into extraembryonic cells, including amnion, with de-repression of key genes bearing bivalent promoters; these cells fail to fully activate genes vital for spermatogenesis and oogenesis, with their promoters remaining methylated. Our study elucidates the framework of epigenetic reprogramming in humans, making a fundamental advance in human biology, and through the generation of abundant mitotic pro-spermatogonia and oogonia-like cells, represents a milestone for human in vitro gametogenesis (IVG) research and its potential translation into reproductive medicine.

Study JGAS000690

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