(364) Optimizing the Epigenetic Sperm Imprint of Obese Mice in ART

Optimizing the Epigenetic Sperm Imprint of Obese Mice in ART

Therese Freire¹, Marie Pignol¹, Marine Roux¹, Liangxi Wang¹, Jo Iversen², Clémentine Placet¹, Maud Maillaut¹, Romain Barrès^1,2

1. Institut de Pharmacologie Moléculaire et Cellulaire, CNRS-INSERM and Université Côte d'Azur, Valbonne, France

2. Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark

Abstract Text:

Infertility affects approximately 17.5% of reproductive-aged couples worldwide, with male factors contributing to nearly half of the cases. Male infertility is influenced by genetic, environmental, and lifestyle factors, including obesity, which is closely associated with reduced fertility, health, and lifespan, and an increased risk of passing deleterious phenotypes to offspring. As global obesity rises, the number of fathers with obesity planning to conceive also grows, necessitating novel assisted reproductive technologies (ART) to mitigate obesity-related fertility challenges. Aberrant DNA methylation in spermatozoa correlates with poor semen parameters, male infertility, and increased rates of spontaneous abortions and imprinting disorders. Genomic imprinting, an epigenetic mechanism regulated by DNA methylation, is crucial for embryonic development, and defects in imprinted genes can lead to severe developmental and behavioural disorders. At the same time, several studies have also suggested the correlation between ART and increased incidences of imprinting disorders. Indeed, the development of techniques that can help identify and minimize DNA methylation aberrations offers valuable insights into both fertility and the long-term health of offspring. This project aims to investigate how obesity affects sperm DNA methylation and the transmission of disease (such as genomic imprinting disorders) to offspring. Using an animal model of C57Bl/6JRj mice, we placed 4-week old male mice on either a control or Western diet. Caudal sperm was collected after 6 weeks, then prepared using various methods, including swim out only, swim up, density gradient centrifugation and the use of the Zymot device. DNA extraction was performed on samples and targeted amplicon sequencing was used to determine DNA methylation levels in genomic imprinting regions. Our initial findings demonstrate that sperm isolated via swim-out only exhibit distinct DNA methylation patterns in imprinting regions compared to those prepared using swim-up or density gradient centrifugation, regardless of diet. This study seeks to optimize sperm separation methods and ART outcomes, with the goal of improving the health of future generations. By integrating expertise in epigenetics, metabolism, and reproductive health, the study will provide valuable insights into the molecular mechanisms underlying male infertility, particularly for obese individuals. This work will help inform future ART strategies, contributing to better reproductive outcomes and improved long-term health for offspring.