8 results on '"Tozour J"'
Search Results
2. A pre-neoplastic epigenetic field defect in HCV-infected liver at transcription factor binding sites and polycomb targets
- Author
-
Wijetunga, N A, Pascual, M, Tozour, J, Delahaye, F, Alani, M, Adeyeye, M, Wolkoff, A W, Verma, A, and Greally, J M
- Abstract
The predisposition of patients with Hepatitis C virus (HCV) infection to hepatocellular carcinoma (HCC) involves components of viral infection, inflammation and time. The development of multifocal, genetically distinct tumours is suggestive of a field defect affecting the entire liver. The molecular susceptibility mediating such a field defect is not understood. One potential mediator of long-term cellular reprogramming is heritable (epigenetic) regulation of transcription, exemplified by DNA methylation. We studied epigenetic and transcriptional changes in HCV-infected livers in comparison with control, uninfected livers and HCC, allowing us to identify pre-neoplastic epigenetic and transcriptional events. We find the HCV-infected liver to have a pattern of acquisition of DNA methylation targeted to candidate enhancers active in liver cells, enriched for the binding sites of the FOXA1, FOXA2 and HNF4A transcription factors. These enhancers can be subdivided into those proximal to genes implicated in liver cancer or to genes involved in stem cell development, the latter distinguished by increased CG dinucleotide density and polycomb-mediated repression, manifested by the additional acquisition of histone H3 lysine 27 trimethylation (H3K27me3). Transcriptional studies on our samples showed that the increased DNA methylation at enhancers was associated with decreased local gene expression, results validated in independent samples from The Cancer Genome Atlas. Pharmacological depletion of H3K27me3 using the EZH2 inhibitor GSK343 in HepG2 cells suppressed cell growth and also revealed that local acquired DNA methylation was not dependent upon the presence of polycomb-mediated repression. The results support a model of HCV infection influencing the binding of transcription factors to cognate sites in the genome, with consequent local acquisition of DNA methylation, and the added repressive influence of polycomb at a subset of CG-dense cis-regulatory sequences. These epigenetic events occur before neoplastic transformation, resulting in what may be a pharmacologically reversible epigenetic field defect in HCV-infected liver.
- Published
- 2017
- Full Text
- View/download PDF
3. Serum Gonadotropin Levels Predict Post-Trigger Luteinizing Hormone Response in Antagonist Controlled Ovarian Hyperstimulation Cycles.
- Author
-
Wiltshire A, Tozour J, Hamer D, Akerman M, McCulloh DH, Grifo JA, and Blakemore J
- Subjects
- Female, Humans, Retrospective Studies, Fertilization in Vitro, Ovulation Induction, Luteinizing Hormone, Chorionic Gonadotropin, Follicle Stimulating Hormone, Human, Gonadotropin-Releasing Hormone, Ovarian Hyperstimulation Syndrome
- Abstract
The objective of this study was to investigate the utility of using serum gonadotropin levels to predict optimal luteinizing hormone (LH) response to gonadotropin releasing hormone agonist (GnRHa) trigger. A retrospective cohort study was performed of all GnRH-antagonist controlled ovarian hyperstimulation (COH) cycles at an academic fertility center from 2017-2020. Cycles that utilized GnRHa alone or in combination with human chorionic gonadotropin (hCG) for trigger were included. Patient and cycle characteristics were collected from the electronic medical record. Optimal LH response was defined as a serum LH ≥ 40 mIU/mL on the morning after trigger. Total sample size was 3865 antagonist COH cycles, of which 91% had an optimal response to GnRHa trigger. Baseline FSH (B-FSH) and earliest in-cycle LH (EIC-LH) were significantly higher in those with optimal response. Multivariable logistic regression affirmed association of optimal response with EIC-LH, total gonadotropin dosage, age, BMI and Asian race. There was no difference in the number of oocytes retrieved (p = 0.14), maturity rate (p = 0.40) or fertilization rates (p = 0.49) based on LH response. There was no difference in LH response based on use of combination vs. GnRHa alone trigger (p = 0.21) or GnRHa trigger dose (p = 0.46). The EIC-LH was more predictive of LH trigger response than B-FSH (p < 0.005).The optimal B-FSH and EIC-LH values to yield an optimal LH response was ≥ 5.5 mIU/mL and ≥ 1.62 mIU/mL, respectively. In an era of personalized medicine, utilizing cycle and patient characteristics, such as early gonadotropin levels, may improve cycle outcomes and provide further individualized care., (© 2022. The Author(s), under exclusive licence to Society for Reproductive Investigation.)
- Published
- 2023
- Full Text
- View/download PDF
4. Universal SARS-CoV-2 polymerase chain reaction screening and assisted reproductive technology in a coronavirus disease 2019 pandemic epicenter: screening and cycle outcomes from a New York City fertility center.
- Author
-
Shaw J, Tozour J, Blakemore JK, and Grifo J
- Subjects
- Adult, COVID-19 epidemiology, Cohort Studies, Female, Fertile Period physiology, Humans, New York City epidemiology, Pandemics, Retrospective Studies, COVID-19 diagnosis, Fertility Clinics standards, Mass Screening methods, Polymerase Chain Reaction methods, Reproductive Techniques, Assisted standards, SARS-CoV-2 isolation & purification
- Abstract
Objective: To evaluate the prevalence of coronavirus disease 2019 (COVID-19) and efficacy of a universal screening program in patients undergoing controlled ovarian stimulation (COS)., Design: Single-center retrospective cohort study., Setting: Academic fertility center in an epicenter of the COVID-19 pandemic., Patient(s): All patients undergoing COS from June 17, 2019, to February 28, 2021., Intervention(s): Universal COVID-19 screening starting June 17, 2020, with SARS-CoV-2 polymerase chain reaction testing within 5 days of oocyte retrieval, patient-reported symptom screening, and temperature monitoring., Main Outcomes Measure(s): The primary outcome was the number of positive COVID-19 cases in patients undergoing COS cycles. The secondary outcomes were cycle outcomes compared with before COVID-19 COS cycles, adverse outcomes in COVID-canceled cycles, and center-specific COVID-19 detection rates compared with New York City cases., Result(s): From June 17, 2020, to February 28, 2021, 1,696 COS cycles were initiated with only seven positive COVID-19 cases for an overall positivity rate of 0.4%. When compared with before COVID cycles from June 17, 2019, to February 28, 2020, the volume of COS cycles were higher, while the overall cycle cancelation rate was lower during COVID-19. Cycle outcomes including oocyte yield and blast utilization rates were unchanged from pre-COVID cycles. Cases of COVID-19, while very low, occurred more frequently during surges in New York City rates., Conclusion(s): Assisted reproductive technology can be performed during the COVID-19 pandemic utilizing frequent universal screening and safe practices with low SARS-CoV-2 positivity, low cycle cancelation rates, and positive patient outcomes., (Copyright © 2021 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
5. Time to revisit the adage: relax and you will get pregnant.
- Author
-
Feinberg EC and Tozour J
- Subjects
- Female, Humans, Pregnancy
- Published
- 2021
- Full Text
- View/download PDF
6. Prenatal Hyperglycemia Exposure and Cellular Stress, a Sugar-Coated View of Early Programming of Metabolic Diseases.
- Author
-
Tozour J, Hughes F, Carrier A, Vieau D, and Delahaye F
- Subjects
- Blood Glucose genetics, Diabetes, Gestational genetics, Diabetes, Gestational pathology, Epigenesis, Genetic genetics, Female, Glucose adverse effects, Glucose metabolism, Humans, Hyperglycemia complications, Hyperglycemia pathology, Male, Metabolic Diseases etiology, Metabolic Diseases pathology, Obesity metabolism, Obesity pathology, Pregnancy, Sex Characteristics, Sugars adverse effects, Sugars metabolism, Diabetes, Gestational metabolism, Hyperglycemia metabolism, Metabolic Diseases metabolism, Obesity genetics
- Abstract
Worldwide, the number of people with diabetes has quadrupled since 1980 reaching 422 million in 2014 (World Health Organization). This distressing rise in diabetes also affects pregnant women and thus, in regard to early programming of adult diseases, creates a vicious cycle of metabolic dysfunction passed from one generation to another. Metabolic diseases are complex and caused by the interplay between genetic and environmental factors. High-glucose exposure during in utero development, as observed with gestational diabetes mellitus (GDM), is an established risk factor for metabolic diseases. Despite intense efforts to better understand this phenomenon of early memory little is known about the molecular mechanisms associating early exposure to long-term diseases risk. However, evidence promotes glucose associated oxidative stress as one of the molecular mechanisms able to influence susceptibility to metabolic diseases. Thus, we decided here to further explore the relationship between early glucose exposure and cellular stress in the context of early development, and focus on the concept of glycemic memory, its consequences, and sexual dimorphic and epigenetic aspects.
- Published
- 2020
- Full Text
- View/download PDF
7. A polycomb-mediated epigenetic field defect precedes invasive cervical carcinoma.
- Author
-
Wijetunga NA, Ben-Dayan M, Tozour J, Burk RD, Schlecht NF, Einstein MH, and Greally JM
- Subjects
- Biopsy, Carcinogenesis, Carcinoma metabolism, Carcinoma virology, Cluster Analysis, Cohort Studies, DNA Methylation, DNA, Viral genetics, Disease Progression, Enhancer of Zeste Homolog 2 Protein metabolism, Female, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Humans, Papillomaviridae, Papillomavirus Infections virology, Polycomb-Group Proteins metabolism, Transcription, Genetic, Uterine Cervical Neoplasms metabolism, Uterine Cervical Neoplasms virology, Uterine Cervical Dysplasia pathology, Uterine Cervical Dysplasia virology, Carcinoma genetics, Enhancer of Zeste Homolog 2 Protein genetics, Epigenesis, Genetic, Uterine Cervical Neoplasms genetics
- Abstract
Human papillomavirus (HPV)-associated cervical carcinoma is preceded by stages of cervical intra-epithelial neoplasia (CIN) that can variably progress to malignancy. Understanding the different molecular processes involved in the progression of pre-malignant CIN is critical to the development of improved predictive and interventional capabilities. We tested the role of regulators of transcription in both the development and the progression of HPV-associated CIN, performing the most comprehensive genomic survey to date of DNA methylation in HPV-associated cervical neoplasia, testing ~2 million loci throughout the human genome in biopsies from 78 HPV+ women, identifying changes starting in early CIN and maintained through carcinogenesis. We identified loci at which DNA methylation is consistently altered, beginning early in the course of neoplastic disease and progressing with disease advancement. While the loss of DNA methylation occurs mostly at intergenic regions, acquisition of DNA methylation is at sites involved in transcriptional regulation, with strong enrichment for targets of polycomb repression. Using an independent cohort from The Cancer Genome Atlas, we validated the loci with increased DNA methylation and found that these regulatory changes were associated with locally decreased gene expression. Secondary validation using immunohistochemistry showed that the progression of neoplasia was associated with increasing polycomb protein expression specifically in the cervical epithelium. We find that perturbations of genomic regulatory processes occur early and persist in cervical carcinoma. The results indicate a polycomb-mediated epigenetic field defect in cervical neoplasia that may represent a target for early, topical interventions using polycomb inhibitors., Competing Interests: The authors declare no potential conflicts of interest.
- Published
- 2016
- Full Text
- View/download PDF
8. Mosaic epigenetic dysregulation of ectodermal cells in autism spectrum disorder.
- Author
-
Berko ER, Suzuki M, Beren F, Lemetre C, Alaimo CM, Calder RB, Ballaban-Gil K, Gounder B, Kampf K, Kirschen J, Maqbool SB, Momin Z, Reynolds DM, Russo N, Shulman L, Stasiek E, Tozour J, Valicenti-McDermott M, Wang S, Abrahams BS, Hargitai J, Inbar D, Zhang Z, Buxbaum JD, Molholm S, Foxe JJ, Marion RW, Auton A, and Greally JM
- Subjects
- Adult, Child Development Disorders, Pervasive pathology, Chromosome Aberrations, Female, Gene Expression Profiling, Genome, Human, Haplotypes, Humans, Male, Maternal-Fetal Relations, Middle Aged, Pregnancy, Age Factors, Child Development Disorders, Pervasive genetics, DNA Methylation genetics, Epigenesis, Genetic, Mosaicism
- Abstract
DNA mutational events are increasingly being identified in autism spectrum disorder (ASD), but the potential additional role of dysregulation of the epigenome in the pathogenesis of the condition remains unclear. The epigenome is of interest as a possible mediator of environmental effects during development, encoding a cellular memory reflected by altered function of progeny cells. Advanced maternal age (AMA) is associated with an increased risk of having a child with ASD for reasons that are not understood. To explore whether AMA involves covert aneuploidy or epigenetic dysregulation leading to ASD in the offspring, we tested a homogeneous ectodermal cell type from 47 individuals with ASD compared with 48 typically developing (TD) controls born to mothers of ≥35 years, using a quantitative genome-wide DNA methylation assay. We show that DNA methylation patterns are dysregulated in ectodermal cells in these individuals, having accounted for confounding effects due to subject age, sex and ancestral haplotype. We did not find mosaic aneuploidy or copy number variability to occur at differentially-methylated regions in these subjects. Of note, the loci with distinctive DNA methylation were found at genes expressed in the brain and encoding protein products significantly enriched for interactions with those produced by known ASD-causing genes, representing a perturbation by epigenomic dysregulation of the same networks compromised by DNA mutational mechanisms. The results indicate the presence of a mosaic subpopulation of epigenetically-dysregulated, ectodermally-derived cells in subjects with ASD. The epigenetic dysregulation observed in these ASD subjects born to older mothers may be associated with aging parental gametes, environmental influences during embryogenesis or could be the consequence of mutations of the chromatin regulatory genes increasingly implicated in ASD. The results indicate that epigenetic dysregulatory mechanisms may complement and interact with DNA mutations in the pathogenesis of the disorder.
- Published
- 2014
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.