167 - Adverse Maternal Environments Perturb Hepatic DNA Methylome and Transcriptome Prior to the Adult-onset Non-alcoholic Fatty Liver Disease in Male Mouse Offspring
Saturday, April 29, 2023
3:30 PM – 6:00 PM ET
Poster Number: 167 Publication Number: 167.218
Qi Fu, Children's Mercy Hospital Kansas City, Kansas City, KS, United States; Tomi Pastinen, Children's Mercy Hospitals and Clinics, Kansas City, MO, United States; Warren A. Cheung, Children's Mercy Hospitals and Clinics, Kansas City, MO, United States; Amber Majnik, Medical College of Wisconsin, Milwaukee, WI, United States; Jeffrey Johnston, Children's Mercy Hospitals and Clinics, Kansas City, MO, United States; Xingrao Ke, Children's Mercy Hospital, Kansas City, MO, United States; Robert H. Lane, Children's Mercy, Kansas City, MO, United States
Research Scientist Children's Mercy Hospital Kansas City Kansas City, Missouri, United States
Background: Non-alcoholic fatty liver disease (NAFLD) stands as the most common liver disease in the United States and worldwide. We have previously shown in a mouse model that exposure to adverse early-life environment (AME) increased the incidence of developing adult-onset NAFLD. However, the mechanistic link of early-life events and later-onset NAFLD remains elusive. Epigenetics, such as DNA methylation, has been postulated as one of the linkages. Whether and to what extent the hepatic DNA methylome is perturbed prior to the development of offspring NAFLD is unknown. Objective: We hypothesized that AME would perturb offspring hepatic DNA methylome and transcriptome prior to the adult-onset NAFLD. Design/Methods: We exposed female mice to either a control diet (CD) or a western diet (WD) 5 weeks prior to pregnancy and throughout lactation. We added non-invasive variable stressors during last third of pregnancy to dams on the WD diet only creating an AME. Male mice livers were harvested at day (d) 0 (birth) and d21 (weaning) when the livers were not steatotic. In this model, male mice developed NAFLD in adulthood after having been on CD for their entire postweaning lives. Reduced representation of bisulfite sequencing (RRBS) and RNA-Seq were used for measure whole-liver genome methylation and transcriptome, respectively. Results: 1. AME resulted in 5,879 differentially methylated cytosines (DMCs) at d0 and 2,970 at d21 when compared with age-matched controls. Among the DMCs, around 22% and 20% overlapped with cis-regulatory elements (cCREs) [mouse Encyclopedia of DNA elements (mENCODE)], respectively. 2. Majority of the DMCs were distal from transcription start sites (TSSs). These distal DMCs were significantly related to Gene Ontology (GO) biological processes of bile acid secretion and transport and regulation of histone H3-K36 and H3-K4 methylation (the Genomic Regions Enrichment of Annotations Tool). 3. AME did not reveal any differentially expressed gene (DEG) at d0 despite the significant perturbation of DNA methylome. At d21, AME resulted in 121 DEGs which are significantly enriched in multiple GO biological processes, such as fatty acid metabolic process, steroid hormone synthesis, cholesterol biosynthesis, etc.
Conclusion(s): AME perturbed offspring hepatic methylome at birth and weaning prior to the onset of hepatic steatosis. Majority of the DMCs were distal from TSSs and were not correlated with DEGs. We speculate that AME may impact long-range regulation of offspring hepatic chromatin function to increase the incidence of NAFLD later in life.
