Ayano Shiba, PhD (NIN) & Han Jiao, PhD (Amsterdam UMC)

Host: Andries Kalsbeek
Group leader van Kalsbeek Group
Email: a.kalsbeek@nin.knaw.nl

Guest Speaker:
Ayano Shiba, PhD (NIN) & Han Jiao, PhD (Amsterdam UMC)

Title: “Watch the clock, not the scale”.

Abstract:
The hypothalamic suprachiasmatic nucleus (SCN) is the circadian pacemaker of the mammalian brain. It integrates both environmental and endogenous information to modulate various physiological and behavioral processes. In addition to light, also food intake and physical activity are able to entrain SCN circadian rhythmicity. Disruption of this circadian rhythmicity is an important factor driving the current-day high prevalence of obesity and type-2 diabetes. While the impact of incorrect timing of caloric intake on circadian disruption is widely acknowledged, the contribution of physical activity remains relatively understudied. Ayano Shiba will show how voluntary wheel running may modulate SCN activity through the immediate early gene ΔFOSB. Moreover, in her search for the link between physical activity and the central brain clock she also found an interesting sexdifference. Given its role in long-term plasticity and behavioral adaptations, ΔFOSB may provide a molecular link between voluntary wheel running and/or the estrous cycle and the output of the SCN and its related behavioral adaptations. Time-restricted eating has shown great promise for improving metabolic health in obese humans, but its mechanism is still not completely resolved. Han Jiao will show how timerestricted feeding (TRF) affects microglial immunometabolism. TRF reinforced the rhythmicity of the microglial transcriptome, and prevented the HFD-induced increase in hypothalamic microglial cell number. However, TRF failed to reverse HFD-induced microglial immune dysfunction and metabolic disturbances, including suppressed electron transport chain activity and impaired metabolic flexibility. These findings suggest that obesity-driven microglial immunometabolic reprogramming persists despite TRF-induced weight loss and may contribute to obesogenic memory and weight regain after weight loss induced by dietary interventions.