Assisted Reproductive Technology – Epigenetic Workshop

September 12, 2018

Le Westin
270 Saint-Antoine St W
Montreal, QC H2Y 0A3

Please join us to this RQR-CFAS joint workshop on Epigenetics taking place on September 12th at Le Westin. Note that this is a free event but space is limited: you must register to attend.

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Summary

This workshop is at the interface between the basic research on the transmission of phenotypic attributes to infant (F1) through epigenetic mechanisms and the Assisted Reproduction Technologies (ART). The goal is to identify and explain the potential factors involved in ART that may increase the effect of the environment (pre-conceptional, and during the IVF procedures) in the programming of future babies.  The use of animal models may improve the mechanistic understanding of the process since tissues are not always available in human for obvious ethical considerations.

Learning Objectives

  • To realize the role and impact of the early gamete’s and embryo’s environment on the future phenotype ( health of the IVF babies )
  • To create an awareness of which methods or procedures are the most problematic in ART.

Résumé

Cet atelier est à l’interface entre la recherche fondamentale sur la transmission des attributs phénotypiques au nourrisson (F1) à travers les mécanismes épigénétiques et les techniques de procréation médicalement assistée (PMA L’objectif est d’identifier et d’expliquer les facteurs potentiels impliqués dans la PMA qui peuvent augmenter l’effet de l’environnement (pré-conception, et pendant les procédures de FIV) dans la programmation des futurs bébés. L’utilisation de modèles animaux peut améliorer la compréhension mécanistique du processus puisque les tissus ne sont pas toujours disponibles chez l’humain pour des considérations éthiques évidentes.

Objectifs d’apprentissage

  • Réaliser le rôle et l’impact de l’environnement précoce des gamètes et des embryons sur le phénotype futur (santé des bébés FIV)
  • Faire prendre conscience des méthodes ou procédures les plus problématiques en ART.

Prof. Gromoll is an endocrinologist working at the Centre of Reproductive Medicine and Andrology (CeRA) at the University of Muenster, Germany.

His main interest is the endocrine regulation of spermatogenesis and the epigenetics of male germ cells. Most of his studies are strictly translational and adress male infertility. He has published more than 190 articles in peer-reviewed journals.

From 2011-2014 he was acting as the President of the German Endocrine Society. From 2008-2016 he was the speaker of the Research Unit ‘Germ Cell Potential’ which covered aspects of gametogenesis shared by male and female germ cells. Since 2017 he is heading a new Research Unit ‘Male Germ Cells: from genes to function’ , which focusses on the genetics and epigenetics of male infertility.

Sperm Epimutations: Origin and Consequences for Reproduction

The influence of epigenetic modifications on reproduction and on the function of male germ cells has been thoroughly demonstrated. In particular, aberrant DNA methylation levels in sperm have been associated with abnormal sperm parameters, lower fertilization rates and impaired embryo development. However, it is not clear whether aberrant DNA methylation levels detected in infertile men are caused by widespread epimutations affecting all sperm produced by an individual or by the concomitant existence of populations of sperm with different methylation patterns. Our recent data indicate that human sperm might be epigenetically heterogeneous and that abnormal DNA methylation levels found in the sperm of infertile men could be due to the presence of sperm populations with different epigenetic quality. However, the origin and the contribution of different germ cell types to this suspected heterogeneity is unclear. We therefore started to analyze spermatogonia cultured and isolated from testicular biopsies from different infertile men. By performing deep bisulfite sequencing we also noticed DNA methylation heterogeneity among spermatogonial populations of different patients. Based on these results, we propose a model in which spermatogonial stem cell variability, either intrinsic or due to external factors (such as endocrine action and environmental stimuli), can lead to epigenetic sperm heterogeneity, sperm epimutations and male infertility. The elucidation of the precise causes for epimutations, the conception of adequate therapeutic options and the development of sperm selection technologies based on epigenetic quality should be regarded as crucial to the improvement of ART outcome in the near future.

Learning Objectives

  1. Male germ cell epigenetic reprogramming during spermatogenesis and fertilization.
  2. Origin of epimutations and impact of genetics and environment.
  3. Consequences of epimutations for reproductive health and progeny

I am a second year graduate student at McGill University in Dr. Sarah Kimmins lab. I have an Honours in Life Sciences from McGill University. My research is focused on understanding epigenetic inheritance through the paternal germline. Briefly, my project involves understanding how a paternal folate deficiency can impact the sperm epigenome and how multiple epigenetic stressors can cumulatively damage the sperm epigenome and enhance the abnormality severity in the offspring. Additionally, I aim to understand how a damaged sperm epigenome is transmitted into the pre-implantation embryo and impact its gene expression, thus its development.

The effects of a folate deficient diet on the sperm epigenome and the implications on offspring development

Birth defects affect over 8 million infants every year and children born in populations of low socio-economic background have increased susceptibility of developing a complex disease such as diabetes and mental illness (WHO, 2015). A father’s environmental exposure to toxicants and poor diet influence disease transmission across generations, potentially through epigenetic inheritance (Lambrot et al., 2015 & Li et al., 2017 & Carone et al., 2010). However, the consequences of environmental stressors on the sperm epigenome and the paternal contributions towards embryonic development need to be elucidated. A better understanding of paternal influences on offspring development will highlight the need for better men’s preconception health advising and minimize the risk of paternal inherited complex diseases. We aim to better understand how a folate deficiency in male mice beginning at weaning affects their sperm epigenome and how numerous epigenetic stressors can cumulatively erode the sperm epigenome, and enhance the number of abnormalities in the offspring. This presentation will first focus on the consequences of a paternal folate deficiency on E18.5 mouse fetuses and E18.5 pregnancies. We will then examine how a paternal folate deficiency fed to transgenic male mice with a pre-existing damaged sperm epigenome because of the overexpression of the histone demethylase KDM1A, give rise to more severe developmental abnormalities in the offspring. Finally, we will determine the consequences of a paternal folate deficiency beginning at weaning on the sperm epigenome from ChIP-Sequencing data for the histone mark H3K4me3, and the implications of further damaging the sperm epigenome of male TG mice.

Learning Objectives

  1. Demonstrate the importance of paternal pre-conception health to ensure proper offspring development and minimize negative pregnancy outcomes.
  2. Determine the dynamic response of the sperm epigenome to environmental stressors such as a folate deficiency.
  3. Assess the consequences of multiple epigenetic stressors on the sperm epigenome and the implications of an eroded sperm epigenome on offspring development.

Pauline Herst is a PhD candidate for the department of animal sciences at Laval University. Before coming to Laval University, she studied Biomedical Sciences at Maastricht University in The Netherlands and successfully finished her studies with a Master of Science in 2015. Her research interests include the effect of Arctic pollutants on sperm epigenetics, generational paternal epigenetic inheritance and folic acid as a dietary supplement to protect the sperm epigenome. Recently, she started a new project, in collaboration with the Norwegian Polar Institute, to investigate the effect of Arctic pollutants on Norwegian polar bear dams and their cubs. Besides her PhD, she also runs her own health and wellness blog, which she uses as a platform to communicate the science behind health and happiness.

Does the Apple Fall Far from the Tree? In Utero Exposure to Persistent Organic Pollutants Alters Sperm miRNA Expression across Multiple, Unexposed Generations

Great concern has arisen concerning high levels of persistent organic pollutants (POPs) in the Arctic food chain – as they may be associated with multigenerational changes in epigenetic marks following in utero exposure. We hypothesize that in utero exposure to POPs alters miRNA expression in sperm and the sperm of his subsequent generations. Furthermore we hypothesize that nutritional folic acid (FA) supplementation moderates the POPs-induced dysregulation of miRNA expression. MiRNA sequencing results show that sperm miRNA expression is perturbed transgenerationally due to in utero POPs and POPs+FA exposure. Data also indicate a moderating effect of dietary FA against POPs.

Learning Objectives

  1. At the end of this presentation, participants will be able to​ differentiate between paternally mediated intergenerational and transgenerational epigenetic inheritance.
  2. At the end of this presentation, participants will be able to explain how in utero exposure to persistent organic pollutants affects the father’s sperm miRNA profile and subsequent generations.
  3. At the end of this presentation, participants will be able to understand the possible generational protective role of dietary folic acid supplementation against in utero exposure to persistent organic pollutants on sperm miRNA expression.

Anne-Sophie graduated from McGill University with a major in Pharmacology & Therapeutics in June 2016. During her undergraduate degree, she had the opportunity to be involved in different projects in the field of epigenetic. Wanting to pursue that branch of science, she joined Dr. Kimmins’ Lab during the summer of 2016 as a Master’s student and is now a Ph.D. Candidate. Her current project aims to understand how paternal obesity, induced by a high-fat diet, can predispose future generations to metabolic syndrome.

Understanding the Role of Paternal Obesity in the Transmission of Metabolic Syndrome Across Generations

Transgenerational epigenetic inheritance is the transmission of environmental information across generations. Increasing evidence supports the contribution of paternal environment exposures and diets on intergenerational health. The underlying mechanisms are thought to involve the sperm epigenome but still remain elusive. With the use of a transgenic mouse model with an altered epigenome, combined with an environmental challenge in the form of a high-fat diet, the current study highlights that paternal obesity leads to metabolic syndrome in offspring, as well as sex-specific effects where only male offspring show altered metabolism, while females sustain consistent metabolic profiles. Whether these effects can be transmitted beyond the F1 offspring remains unknown.

Learning Objectives

  1. Consider the importance of paternal preconception health on reproductive outcomes
  2. Exemplify the impact of paternal environment on future generations’ health with past and current studies
  3. Discuss issues of current clinical practices in fertility clinics related to men’s role in preconception

After completing a bachelor in Biochemistry at the Université de Sherbrooke, I joined Dr Serge McGraw lab at the CHU Ste-Justine research center and Université de Montréal where I am currently pursuing a PhD in Biochemistry, to study the effect of an early alcohol exposure on embryo development.

Early Alcohol Exposure Induces Sex Specific DNA Methylation Perturbations in Mid-Gestation Mouse Embryos and Placentas

Even though Prenatal Alcohol Exposure (PAE) is known to altered epigenetic profiles during brain development and be part of Fetal Alcohol Spectrum Disorder (FASD) etiology, the consequences of PAE during early embryonic life on the future epigenetic landscape of the conceptus are still unknown. Our research hypothesis is that a PAE during preimplantation will initiate DNA methylation dysregulations that will be perpetuated through development and be variable depending on the sex of the embryo. Our objective is to identify sex-specific DNA methylation dysregulations in the forebrain and placenta of mid-gestation ethanol-exposed mouse embryos. We investigated FASD in mouse 8-cell embryos by injecting ethanol at 2.5 days of pregnancy. We then collected E10.5 embryos and placentas and established quantitative DNA methylation profiles in FASD samples (n= 6 males ; 6 females) vs control samples (n= 4 males ; 4 females) by Reduced Representation Bisulfite Sequencing. Male forebrains have a higher number of depleted DNA methylation regions than females (1677 vs 417) with an enrichment related to cell adhesion and neuron morphogenesis. Female placentas seem to be more affected than males with an enrichment in pathways related to transmembrane signaling and synapse assembly. Altogether, our results allow us to have a better understanding of how epigenetic perturbations can alter the normal function of the brain and could explain the heterogeneity observed in the phenotypes across children affected.

Learning Objectives

  1. At the end of this talk, participants will be able to describe how adverse uterine environment during the first days of pregnancy can affect embryo development.
  2. Participants will be able to describe how the embryonic epigenetic program can be modulated by maternal environment.
  3. Participants will be able to discuss how an early alcohol exposure can have a negative outcome on embryo development and lead to later life abnormal behavioural and cognitive functions.

A PhD student of the Centre de recherche en reproduction, développement et santé intergénérationnelle (CRDSI), Département des Sciences Animales, Faculté des Sciences de l’Agriculture et de l’Alimentation, Université Laval, Québec, Canada.

As a member of Prof. Marc-André Sirard’s team, his projects mainly focus on the mechanisms of paternal age effects on the bovine early embryos.

Paternal Effects of Peri-Pubertal Bulls on the Transcriptomes and Epigenomes of Blastocysts

The bull’s age affects the epigenetic information of blastocysts and alters the genes expression which could further impact the quality of embryos.

Learning Objectives

  1. Recognize the paternal age effects on the bull semen quality.
  2. Acquire the transgenerational impacts of bull’s age on early embryos.
  3. Evaluate the risks of applying pre-pubertal bull for breeding purpose.

Dr. Rinaudo is a Reproductive Endocrinologist based in San Francisco, California. He is currently Professor in residence at the University of California San Francisco. He received a MD, PhD at the University of Turin, Italy and then moved to the US. He completed a Residency in obstetrics and Gynecology at Yale University and a Fellowship in Reproductive Endocrinology at the University of Pennsylvania. The focus of his research is to understand how in vitro fertilization and in vitro culture during the pre-implantation period affect fetal and adult development. This has particular relevance in light of the widespread use of artificial reproductive techniques (ART). In fact, fetal adaptations in utero to adverse conditions can lead to specific diseases in the adult, including diabetes, high blood pressure and coronary heart disease. This phenomenon, termed the developmental origin of adult health and disease or the Barker hypothesis, has been extrapolated back to preimplantation development.

Epigenetic Profiling of Preimplantation Embryos: Implications for Assisted Reproductive Technologies

This presentation will highlight the changes that occur in mouse embryo following IVF. In particular we will describe the DNA methylation and chromatin changes present in the inner cell mass of male female mouse embryos generated spontaneously or after IVF

Learning Objectives

  1. Describe the DNA methylation changes that occur during development
  2. Understand how the environment can affect epigenetic changes during development
  3. Understand if epigenetic differences exist in male or female embryos

Marie-Christine Roy holds a master’s degree in bioethics from the University of Montreal. Her research interests are in reproductive ethics, the ethics of epigenetics and health policy ethics. She works as an ethics consultant for the Institut national d’excellence en santé et en services sociaux and is the coordinator of the Activity on the ethical, legal and social issues for expanded non-invasive prenatal screening & 1st-tier non-invasive prenatal testing, part of the PEGASUS-2 project (PErsonalized Genomics for prenatal Abnormalities Screening USing maternal blood).

Epigenetic Risks Associated with ART : Some Ethical Issues

The use of assisted reproductive technologies (ART) allows many coping with infertility to conceive. However, an emerging body of evidence suggests that ART could carry epigenetic risks for those conceived through the use of these technologies. In accordance with the Developmental Origins of Health and Disease (DOHaD) hypothesis, ART could increase the risk of developing late-onset diseases through epigenetic mechanisms, since superovulation, fertilization methods and embryo culture could impair the embryo’s epigenetic reprogramming. Such epigenetic risks raise ethical issues for all stakeholders: prospective parents and children, health professionals, and society. This research focuses on ethical issues for the prospective parents, future children and healthcare providers raised by the consideration of these risks when using ART.

To highlight these issues, we used Beauchamp and Childress’s principlist approach, which states that autonomy, beneficence, non-maleficence and justice are the cardinal principles to be considered when a tension within medicine or biomedical research occurs.

We argue that an ethical tension can emerge between respect for the reproductive autonomy of prospective parents and the duty to minimize the risks for potential children. A second ethical tension can emerge between the parents’ right to make an informed choice about the use of ART, and the reluctance of health professionals to communicate epigenetic risk given its uncertain validity.

We argue that prospective parents and health professionals have a shared responsibility to promote the best interests of the future child. We also argue in favor of further research on the effects of ART on the health of future children, and in favor of clinical guidelines that prioritize the use of techniques that carry less epigenetic risk and that assist health professionals in communicating the epigenetic risks associated with ART. Finally, we suggest that this communication be done within the patient-centered approach.

Learning Objectives

  1. At the end of this session, participants will be able to recognize some ethical issues raised by the epigenetic risks associated with assisted reproductive technologies.
  2. At the end of this session, participants will be able to identify stakeholders’ responsibilities towards future children conceived through assisted reproductive technologies.
  3. At the end of this session, participants will have learned about a renowed approach in bioethics, that is Beauchamp and Childress’ principlist approach.