Mathematical Modeling of Dietary Timing- and Protein Quality-Responsive Liver Circadian Clock and its Function on...

Independent of the suprachiasmatic nucleus, peripheral clocks can be strongly entrained by dietary signals. Although feeding time has been widely studied, the effects of food quality-particularly nutrient availability and stress-on peripheral circadian entrainment and metabolic regulation remain less understood. We developed a semi-mechanistic mathematical model of peripheral clock synchronization and clock-controlled ribosome biogenesis (RiBi) in response to feeding/fasting cycles and rhythms in dietary essential amino acid (EAA) availability. The model integrates EAA-sensitive signaling through mammalian target of rapamycin complex 1 (mTORC1) and the general control nonderepressible 2 (GCN2)-mediated integrated stress response (ISR), together with ribosomal protein expression as a metabolic endpoint. We used the model to examine circadian entrainment under nutrient stress, adaptation during transitions between feeding schedules with EAA insufficiency, and stress-related mechanisms that may restore circadian and metabolic function. Simulations showed that mTORC1 and GCN2-ISR signaling jointly regulate metabolic entrainability and stress adaptation and are required to maintain circadian synchronization and RiBi dynamics during nutrient stress. The model also predicted that differences in homeostatic adaptation can produce individualized recovery trajectories after transient dietary disruption. Finally, appropriate modulation of GCN2-ISR signaling mitigated disruption-associated RiBi hyperactivation by leveraging dietary EAA rhythms to restore clock function. These findings identify dietary EAA stress and its regulatory pathways as important determinants of peripheral circadian entrainment and metabolic adaptation, supporting the development of personalized nutrition-based strategies for circadian disruption-related chronic disease.