Circadian redox oscillations and metabolism

Circadian rhythms are 24-hour oscillations in physiology and behaviour, which allow organisms to anticipate and adapt to the daily demands associated with the day/night cycle. The currently accepted model of the molecular clockwork is described as a transcriptional process, comprised of negative regulatory feedback loops. However, ample evidence underlines the important contribution of non-transcriptional and metabolic oscillations to cellular timekeeping. Here we will summarize recent evidence pointing to the relationship between the transcriptional oscillator and metabolic redox state, with particular emphasis on the potential nodes of interaction. We highlight the intrinsic difficulty to segregate these two tightly coupled and interdependent processes, in living systems, and how disruption in their synchronicity impacts on physiological and pathological processes as diverse as cardiovascular and metabolic disorders, ageing, and cancer.