Intergenerational Arsenic Exposure on the Mouse Epigenome and Metabolic
Physiology
Abstract
Inorganic Arsenic (iAs) is one of the largest toxic exposures to impact
humanity worldwide. Exposure to iAs during pregnancy may disrupt the
proper remodeling of the epigenome of F1 developing offspring and
potentially their F2 grand-offspring via disruption of fetal primordial
germ cells (PGCs). There is a limited understanding between the
correlation of disease phenotype and methylation profile within
offspring of both generations and whether it persists to adulthood. Our
study aims to understand the intergenerational effects of in utero iAs
exposure on the epigenetic profile and onset of disease phenotypes
within F1 and F2 adult offspring, despite the life-long absence of
direct arsenic exposure within these generations. We exposed F0 female
mice (C57BL6/J) to the following doses of iAs in drinking water 2 weeks
before pregnancy until the birth of the F1 offspring: 1 ppb, 10 ppb, 245
ppb, and 2300 ppb. We found sex- and dose-specific changes in weight and
body composition that persist from early time to adulthood within both
generations. Fasting blood glucose challenge suggests iAs exposure
causes dysregulation of glucose metabolism, revealing generational,
exposure, and sex specific differences. Toward understanding the
mechanism, genome-wide DNA methylation data highlights exposure-specific
patterns in liver, finding dysregulation within genes associated with
cancer, T2D, and obesity. We also identified regions containing
persistently differentially methylated CpG sites between F1 and F2
generations. Our results indicate F1 developing embryos and F2 PGCs
retain epigenetic damage established during the prenatal period and are
associated with adult metabolic dysfunction.