Cross-regulatory circuits linking inflammation, high-fat diet, and the circadian clock

Abstract

Mammalian physiology resonates with the daily changes in the external environment, allowing processes such as rest–activity cycles, metabolism, and body temperature to synchronize with daily changes in the surroundings. Studies have identified the molecular underpinnings of robust oscillations in gene expression occurring over the 24-h day, but how acute or chronic perturbations modulate gene expression rhythms, physiology, and behavior is still relatively unknown. In this issue of Genes & Development, Hong and colleagues (pp. 1367–1379) studied how acute and chronic inflammation interacts with the circadian clock. They found that NF-κB signaling can modify chromatin states and modulate expression of genes in the core clock network as well as circadian loco-motor behavior. Interestingly, a high-fat diet (HFD) fed to mice also triggers this inflammation pathway, suggesting that cross-regulatory circuits link inflammation, HFD, and the circadian clock.