University of California, San Francisco (UCSF)

The Role of Protein Aggregation in Normal Aging and Neurodegeneration

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In neurodegenerative diseases, such as Alzheimer’s disease and Huntington’s disease, specific proteins escape the cell’s quality-control system and “clump” together, forming insoluble aggregates. Until now, little was known about protein aggregation during normal aging in the absence of disease. Using a systematic proteomics approach, we discovered that the aging process itself leads to the insolubilization and increased aggregation propensity of several hundred proteins in a tiny microscopic worm called Caenorhabditis elegans. These aggregation-prone proteins have distinct structural and functional proprieties.

An important question is whether this inherent age-dependent protein aggregation impacts neurodegenerative diseases. First, we discovered that known regulators of disease-related protein aggregation are themselves prone to aggregate with age. Second, we showed that higher levels of inherent protein aggregation aggravated the toxicity in a C. elegans Huntington’s disease model. Third, we found that proteins similar to those aggregating in old worms have also been identified as secondary components of human disease aggregates.

Overall, we have characterized inherent protein aggregation as a new biomarker of aging. Understanding which processes modulate this biomarker will bring fresh insight into the mechanisms behind aging and could lead to the identification of therapeutic targets for disease intervention.