The Effect of Preconception Paternal Alcohol Exposure on Epigenetic Remodeling of the H19 and Rasgrf1 Imprinting Control Regions in Mouse Offspring

Abstract

Imprinted loci play a critical role in fetal development. Their expression is often regulated by CCCTC-binding factor (CTCF) protein binding at imprinting control regions (ICRs). Prenatal alcohol exposure has been shown to reduce global DNA methylation in the developing mouse fetus. This study explored the effect of preconception paternal alcohol exposure on DNA methylation at two paternally methylated ICRs (H19 and Rasgrf1) in the sperm of exposed males and somatic DNA of sired offspring. Significant reductions at the H19 CTCF 1 (p = 0.0027) and CTCF 2 (p = 0.0009) binding sites were observed in the offspring of ethanol-treated sires, which was significantly correlated with reduced weight at postnatal days 35–42 (p < 0.05). As birth weight was unaffected and growth was only delayed during the postnatal weaning period, with subsequent re-convergence, we hypothesize that this may be the result of a mental deficit causing delayed establishment of independent feeding following weaning and would explain why this effect is transient. No difference in DNA methylation was observed in the sperm of alcohol-exposed males, indicating that the transmission of the epigenetic signal at conception is not due to altered methylation, but may be the result of an RNA-mediated mechanism or altered chromatin remodeling.

DNA Methylation, Substance Use and Addiction: a Systematic Review of Recent Animal and Human Research from a Developmental Perspective

“…In the second, paternal alcohol consumption in rats was associated with increased Pomc methylation (another gene relevant in stress response) within both parental sperm and offspring hypothalamus, although findings were specific to the male germline [13]. In contrast, the third study [14] found that DNAm in H19 CTCF binding sites-involved in imprinting mechanisms-was reduced in offspring tail blood but not in paternal sperm cells.…”

“…Tissue-and gene-specific DNAm alterations were identified by one study in folate-regulating genes [27]. Finally, no associations were found in opioid-related genes Pdny and Pnoc in the rat amygdala [28], as well as imprinting-control genes H19 and Rasgfl in mouse sperm [14].…”

“…However, the studies reviewed did provide preliminary support for the relevance of timing of substance exposure on DNAm. For example, evidence from animal models demonstrated that substance exposure can influence DNAm even prior to conception, supporting the existence of transgenerational effects [12][13][14]. Studies also pointed to the prenatal period as a particularly sensitive developmental window.…”

Intergenerational Health Responses to Adverse and Enriched Environments

“…Some emerging evidence now indicates, however, that the transgenerational transmission of alcohol abuse is partly epigenetic. Preconceptional paternal alcohol exposure in mice influences two imprinting control regions (32), and spermatogonial stem cells are very sensitive to ethanol (12). The onset of addiction results from interplay of inherited predispositions, such as alcohol-seeking behavior and alcohol availability.…”

Cross-Generational Effects of Alcohol Dependence in Humans on HRAS and TP53 Methylation in Offspring

“…Cross generational effects have been reported with famine experienced by parents affecting medical conditions and longevity in offspring [13,14]. Although not previously reported in humans, animal studies have shown that ethanol administration can influence DNA methylation through the germline in offspring exposed either through fetal exposure [15] or as a result of paternal exposure [16,17]; changes with the potential to alter every somatic cell in the body across generations. Determining if alcohol consumption in the preconception period in parents influences genes involved in cancer risk in offspring is critical to improvement in prevention initiatives.…”