Male obesity impacts DNA methylation reprogramming in sperm

Area of Science:

• Reproductive Biology
• Epigenetics
• Men's Health

Background:

• Male obesity significantly impacts health and mortality, with limited understanding of its effects on sperm and potential transgenerational consequences.
• DNA methylation is crucial for gene regulation, undergoing dynamic changes during sperm development, making it vulnerable to environmental factors like obesity.
• An obesogenic environment may disrupt the epigenetic reprogramming essential for healthy gametogenesis.

Purpose of the Study:

• To investigate the association between male overweight/obesity and DNA methylation profiles in human sperm.
• To explore potential epigenetic alterations in sperm that could be transmitted to offspring.

Main Methods:

• Exploratory analysis comparing DNA methylation profiles of sperm from overweight/obese men (n=20) and normal BMI controls (n=47).
• Utilized Infinium HumanMethylation450 BeadChips to identify CpG sites associated with Body Mass Index (BMI).
• Employed bisulfite sequencing of cloned alleles for individual sperm analysis to determine methylation patterns.

Main Results:

• Identified 3264 CpG sites in human sperm significantly associated with BMI (p < 0.05).
• Overrepresented CpG sites were linked to genes involved in transcriptional regulation, nervous system development, and stem cell pluripotency.
• Methylation differences were observed in a subset of sperm, not uniformly distributed, suggesting targeted epigenetic disruption.

Conclusions:

• Male obesity is linked to altered sperm DNA methylation, potentially affecting epigenetic reprogramming fidelity in specific sperm populations.
• These alterations may indicate an influence on spermatogonia and warrant further investigation for heritability.
• If heritable, these sperm DNA methylation changes could potentially interfere with normal fetal development.