Protein involved in removing Alzheimer’s buildup linked to circadian rhythm

Washington University School of Medicine in St. Louis • December 16, 2020June 28, 2022

Immune cells known as microglia (turquoise with red dots) surround a plaque of the Alzheimer’s protein amyloid (blue). The red dots indicate that the microglia are prepared to remove the potentially damaging plaque. Researchers at Washington University School of Medicine in St. Louis have discovered a protein that links the amyloid-removal process to the circadian clock. The protein, YKL-40, could help explain why people with Alzheimer’s frequently suffer from sleep disturbances, and provide a new target for Alzheimer’s therapies.

Fractured sleep, daytime sleepiness and other signs of disturbance in one’s circadian rhythm are common complaints of people with Alzheimer’s disease, and the problems only get worse as the disease progresses. But the reason for the link between Alzheimer’s and circadian dysfunction is not well understood.