Epigenomic profiling in visceral white adipose tissue of offspring of mice exposed to late gestational sleep fragmentation

BACKGROUND: Sleep fragmentation during late gestation (LG-SF) is one of the major perturbations associated with sleep apnea and other sleep disorders during pregnancy. We have previously shown that LG-SF induces metabolic dysfunction in offspring mice during adulthood. OBJECTIVES: To investigate the effects of late LG-SF on metabolic homeostasis in offspring and to determine the effects of LG-SF on the epigenome of visceral white adipose tissue (VWAT) in the offspring. METHODS: Time-pregnant mice were exposed to LG-SF or control sleep (LG-SC) conditions during the last 6 days of gestation. At 24 weeks of age, lipid profiles and metabolic parameters were assessed in the offspring. We performed large-scale DNA methylation analyses using MeDIP coupled to microarrays (MeDIP-chip) in VWAT of 24-week-old LG-SF and LG-SC offspring (n=8 mice/group). Univariate multiple-testing adjusted statistical analyses were applied to identify differentially methylated regions (DMRs) between the groups. DMRs were mapped to their corresponding genes, and tested for potential overlaps with biological pathways and gene networks. RESULTS: We detected significant increases in body weight (31.7 vs. 28.8 g; p=0.001), visceral (642.1 vs. 497.0 mg; p=0.002) and subcutaneous (293.1 vs. 250.1 mg; p=0.001) fat mass, plasma cholesterol (110.6 vs. 87.6 mg/dL; p=0.001), triglycerides (87.3 vs. 84.1 mg/dL; p=0.003) and HOMA-IR values (8.1 vs. 6.1; p=0.007) in the LG-SF group. MeDIP analyses revealed that 2148 DMRs (LG-SF vs. LG-SC; p< 0.0001, MAT algorithm). A large proportion of the DMR-associated genes have reported functions that are altered in obesity and metabolic syndrome, such as Cartpt, Akt2, Apoe, Insr1, etc. Overrepresented pathways and gene networks were related to metabolic regulation and inflammatory response. CONCLUSIONS: Our findings show a major role for epigenomic regulation of pathways associated with metabolic processes and inflammatory response in VWAT. LG-SF-induced epigenetic alterations may underlies increases in the susceptibility to obesity and metabolic syndrome in offspring.