Maternal intermittent fasting deteriorates offspring metabolism via suppression of hepatic mTORC1 signaling

The metabolic benefits of intermittent fasting (IF) have been well recognized. However, limited studies have examined the relationship between long-term maternal IF before pregnancy and offspring health. In this study, a C57BL/6J mouse model of long-term IF before pregnancy was established: 4-week-old female mice were subjected to alternate-day fasting for 12 weeks and resumed normal diet after mating. Female mice in the control group were fed ad libitum. Offspring mice were weaned at 6 weeks of age and fed a normal chow diet or a 60% high-fat diet. The effects of long-term pre-pregnancy IF on offspring metabolism and its underlying mechanism were examined. We found that neonatal IF offspring weighted significantly less relevant to control mice. This difference gradually disappeared as a result of catch-up growth. In the IF offspring, adipose tissue mass was significantly increased. This alteration was associated with a considerable deterioration in glucose tolerance. No significant difference in food intake was observed. Further, lipid deposition as well as triglyceride contents in the liver were greatly increased. Maternal IF significantly decreased levels of DNA methyltransferase in the liver of offspring. DNA methylation modifications of molecules associated with the mTORC1 signaling pathway were significantly altered, leading to the significant inhibition of mTORC1 signaling. Overexpression of S6K1 activated hepatic mTORC1 signaling and reversed the metabolic dysfunction in IF offspring. In conclusion, long-term pre-pregnancy IF increases hepatic steatosis and adiposity, as well as impairs glucose metabolism in adult offspring. This occurs through DNA methylation-dependent suppression of hepatic mTORC1 signaling activity.