Core Findings - An international study has identified a key protein (SIRT6) that regulates tryptophan metabolism, significantly impacting sleep, mood, and neurodegenerative diseases, providing new research directions for treatment [1][2] Group 1: Tryptophan Metabolism - Tryptophan is a precursor for serotonin and melatonin synthesis, with serotonin playing a crucial role in mood regulation and melatonin maintaining circadian rhythms and promoting sleep [1] - The study found that aging and neurodegenerative diseases can disrupt tryptophan metabolism, although the underlying molecular mechanisms were previously unclear [1] Group 2: SIRT6's Role - Researchers discovered that SIRT6 acts as a "gatekeeper" in maintaining the balance of tryptophan metabolism by actively regulating the expression of related genes [1] - A decline in SIRT6 activity due to aging and neurodegenerative diseases leads to a shift in tryptophan metabolism towards the kynurenine pathway, resulting in decreased serotonin and melatonin production and increased neurotoxins [1] Group 3: Reversibility of Damage - The damage caused by the accumulation of neurotoxic metabolites is not irreversible; in SIRT6-deficient fruit fly models, researchers successfully reversed the accumulation by altering SIRT6-regulated genes, protecting brain tissue and improving motor behavior [2] - This research offers new targets for treating age-related cognitive impairments, insomnia, and depression [2] Group 4: Publication - The research findings have been published in the journal Nature Communications [3]