Circadian Regulation of Adult Stem Cell Homeostasis and Aging.

The circadian clock temporally organizes cellular physiology throughout the day, allowing daily environmental changes to be anticipated and potentially harmful physiologic processes to be temporally separated. By synchronizing all cells at the tissue level, the circadian clock ensures coherent temporal organismal physiology. Recent advances in our understanding of adult stem cell physiology suggest that aging and perturbations in circadian rhythmicity in stem cells are tightly intertwined. Here we discuss how circadian rhythms regulate and synchronize adult stem cell functions and how alterations in clock function during aging modulate the extrinsic and intrinsic mechanisms that determine adult stem cell homeostasis.