Gestational high-fat diet impaired demethylation of Pparα and induced obesity of offspring

Abstract

Gestational and postpartum high-fat diets (HFDs) have been implicated as causes of obesity in offspring in later life. The present study aimed to investigate the effects of gestational and/or postpartum HFD on obesity in offspring. We established a mouse model of HFD exposure that included gestation, lactation and post-weaning periods. We found that gestation was the most sensitive period, as the administration of a HFD impaired lipid metabolism, especially fatty acid oxidation in both foetal and adult mice, and caused obesity in offspring. Mechanistically, the DNA hypermethylation level of the nuclear receptor, peroxisome proliferator-activated receptor-α (Pparα), and the decreased mRNA levels of ten-eleven translocation 1 (Tet1) and/or ten-eleven translocation 2 (Tet2) were detected in the livers of foetal and adult offspring from mothers given a HFD during gestation, which was also associated with low Pparα expression in hepatic cells. We speculated that the hypermethylation of Pparα resulted from the decreased Tet1/2 expression in mothers given a HFD during gestation, thereby causing lipid metabolism disorders and obesity. In conclusion, this study demonstrates that a HFD during gestation exerts long-term effects on the health of offspring via the DNA demethylation of Pparα, thereby highlighting the importance of the gestational period in regulating epigenetic mechanisms involved in metabolism.

Keywords: DNA demethylation; high-fat diet; lipid metabolism; normal chow diet; obesity.

FIGURE 1

Offspring growth curves, liver‐to‐weight ratios and gonadal fat‐to‐weight ratios in F1 offspring at 16 weeks of age. A, bodyweight of F1 male offspring on a normal chow diet or B, high‐fat diet after weaning; C, bodyweight of F1 female offspring on a normal chow diet or D, high‐fat diet after weaning. A, N–N–N = 10 vs H–N–N = 8 vs N–H–N = 11 vs H–H–N = 9; B, N–N–H = 10 vs H–N–H = 9 vs N–H–H = 8 vs H–H–H = 12; C, N–N–N = 8 vs H–N–N = 8 vs N–H–N = 8 vs H–H–N = 9; D, N–N–H = 13 vs H–N–H = 10 vs N–H–H = 9 vs H–H–H = 10. Liver‐to‐weight ratios and gonadal fat‐to‐weight ratios in F1 male offspring on E, a normal chow diet (N–N–N = 10 vs H–N–N = 8 vs N–H–N = 11 vs H–H–N = 9) or F, high‐fat diet (N–N–H = 10 vs H–N–H = 9 vs N–H–H = 8 vs H–H–H = 12) after weaning; liver‐to‐weight ratios and gonadal fat‐to‐weight ratios in F1 female offspring on G, a normal chow diet (N–N–N = 8 vs H–N–N = 8 vs N–H–N = 8 vs H–H–N = 9) or H, high‐fat diet (N–N–H = 13 vs H–N–H = 10 vs N–H–H = 9 vs H–H–H = 10) after weaning. Data are presented as the mean ± SEM *N–N–N vs H–N–N, ⁺N–N–N vs N–H–N, ^§N–N–N vs H–H–N, *N–N–H vs H–N–H, ⁺N–N–H vs N–H–H, ^§N–N–H vs H–H–H. *P < .05, **P < .01, significance was determined by ANOVA

FIGURE 2

Oil Red O‐stained liver cross‐sections showing fat accumulation in F1 offspring mice at 16 weeks of age. A, administration of a NCD after weaning and C, a HFD after weaning in male mice; B, administration of a NCD after weaning and D, a HFD after weaning in female mice

FIGURE 3

Relative expression of genes involved in lipid metabolism disorders in mice at 16 weeks of age. A, expression of genes in livers of F1 male offspring at 16 weeks of age, B, expression of genes in livers of F1 female offspring at 16 weeks of age; a, lipid transport; b, cholesterol metabolism; c, fatty acid transport, d, lipogenesis; e, fatty acid oxidation and f, transcription factors. (n = 5 mice per group). Data are presented as the mean ± SEM *P < .05, **P < .01, significance was determined by ANOVA

FIGURE 4

Relative expression of genes involved in lipid metabolism disorders in livers of mice at E18.5 day. A, expression of genes in male foetal livers; B, expression of genes in female foetal livers; a, lipid transport; b, cholesterol metabolism; c, fatty acid transport; d, lipogenesis; e, fatty acid oxidation and f, transcription factors. (male, n = 5 mice per group; female, n = 6 mice per group). Data are presented as the mean ± SEM, unpaired t test: *P < .05, **P < .01. NCD, normal chow diet; HFD, high‐fat diet

FIGURE 5

Methylation patterns of Pparα and the relative expression of DNA‐modifying enzymes in livers of mice at E18.5 day. A, methylation level of the Pparα promoter in livers of male mice at E18.5 day; B, methylation level of the Pparα promoter in livers of female mice at E18.5 day; C, relative expression of DNA‐modifying enzymes in livers of male mice at E18.5 day; D, relative expression of DNA‐modifying enzymes in livers of female mice at E18.5 day; E, mean DNA methylation in male mice at E18.5 day; F, mean DNA methylation in male mice at E18.5 day (n = 5 mice per group). Data are presented as the mean ± SEM, unpaired t test: *P < .05, **P < .01

FIGURE 6

Methylation patterns of Pparα and the relative expression of DNA‐modifying enzymes in livers of mice at 16 weeks of age. DNA methylation levels of the Pparα promoter in livers of A, male and B, female mice given a normal chow diet after weaning (male, n = 5 mice per group; female, n = 6 mice per group), relative expression of DNA‐modifying enzymes in livers of C, male and D, female mice, E, mean DNA methylation in male mice; F, mean DNA methylation in female mice (male, n = 5 mice per group; female, n = 6 mice per group). Data are presented as the mean ± SEM, significance determined by ANOVA. *P < .05, **P < .01