The epigenetically modulated circadian system: Implications for nutrition and health. Nutritional modulation of the circadian epigenome

Abstract

The biological clock is a complex puzzle of molecular pieces that must work coordinately to ensure a proper cellular function. The circadian epigenome is the most recently discovered set of clock molecular pieces. It involves DNA methylation, histone acetylation/deacetylation, histone methylation/demethylation, and noncoding RNAs. These epigenomic modifications related to the circadian system add complexity to this process. In this regard, the circadian system is similar to the solar system with the CLOCK/BMAL1 heterodimer in the center and the other molecular and epigenomic components of the circadian system orbiting around it. The particular characteristic of the epigenome is that it is modifiable and environmental factors can affect it. Diet is one of the most important environmental factors affecting human health. We must bear in mind that diet is the only environmental factor to which we are exposed along our lives several times every day. We are even exposed to the diet of our mothers before birth. This is important because mother feeding animal studies have shown that mother diet affect circadian-related histone modifications. Diet also modifies circadian-related microRNAs. Here, we described each level of the circadian epigenome and give an insight of how diet modifies each one of them.