This perspective article explores the relationship between circadian rhythms and fatigue, leading to the proposal of circadian nutrition – the science utilizing meal timing to combat fatigue - as a potential intervention. Fatigue, characterized by reduced muscle endurance, strength, and persistent exhaustion, is linked to circadian regulation of metabolism. Recent studies reveal that time-restricted feeding improves muscle endurance, cognitive function, and metabolic health in rodent models through tissue-specific mechanisms and inter-organ communication of circadian signals. The work sheds light on the role of circadian nutrition in combating fatigue.

The research team led by Dr. Hojeong Jeon and Dr. Hyung-Seop Han of the Biomaterials Research Center at the Korea Institute of Science and Technology (KIST), along with Dr. Indong Jun from KIST Europe, has developed a novel stent surface treatment technology using laser patterning.

Human cells contain two types of adenosine deaminases (ADA) each with unique properties: ADA1, which is present in all cells where it modulates intracellular functions and extracellular signaling, and ADA2, which is secreted by immune cells. The exact intracellular functions of ADA2 remain undetermined and less defined than those of ADA1. ADA2 has distinct characteristics, such as low adenosine affinity, heparin-binding ability, and putative lysosomal entry. Here, we confirm that ADA2 is a lysosomal protein that binds toll-like receptor 9 (TLR9) agonists, specifically CpG oligodeoxynucleotides (CpG ODNs). We show that interferon-alpha (IFN-α) is secreted in response to TLR9 activation by CpG ODNs and natural DNA and markedly increases when ADA2 expression is downregulated in plasmacytoid dendritic cells (pDCs). Additionally, the pretreatment of pDCs with RNA further stimulates IFN-α secretion by pDCs after activation with CpG ODNs. Our findings indicate that ADA2 regulates TLR9 responses to DNA in activated pDCs. In conclusion, decreasing ADA2 expression or blocking it with specific oligonucleotides can enhance IFN-α secretion from pDCs, improving immune responses against intracellular infections and cancer.