Characterization of Sex-Based Dna Methylation Signatures in the Airways During Early Life

Sci Rep. 2018 Apr 3;8(1):5526. doi: 10.1038/s41598-018-23063-5.

Abstract

Human respiratory conditions are largely influenced by the individual's sex resulting in overall higher risk for males. Sex-based respiratory differences are present at birth suggesting a strong genetic component. Our objective was to characterize early life sex-based genomic signatures determined by variable X-chromosome methylation in the airways. We compared male versus female genome-wide DNA methylation in nasal airway samples from newborns and infants aged 1-6 months (N = 12). We analyzed methylation signals across CpG sites mapped to each X-linked gene using an unsupervised classifier (principal components) followed by an internal evaluation and an exhaustive cross-validation. Results were validated in an independent population of children (N = 72) following the same algorithm. X-linked genes with significant sex-based differential methylation in the nasal airway of infants represented only about 50% of the unique protein coding transcripts. X-linked genes without significant sex-based differential methylation included genes with evidence of escaping X-inactivation and female-biased airway expression. These genes showed similar methylation patterns in males and females suggesting unbalanced X-chromosome dosage. In conclusion, we identified that the human airways have already sex-based DNA methylation signatures at birth. These early airway epigenomic marks may determine sex-based respiratory phenotypes and overall predisposition to develop respiratory disorders later in life.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Chromosomes, Human, X / genetics
  • CpG Islands / genetics
  • DNA Methylation / physiology*
  • Epigenomics
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Nasal Mucosa / immunology
  • Nasal Mucosa / metabolism*
  • Sex Characteristics*