Stress and aging induce distinct polyQ protein aggregation states

Area of Science:

• Cell biology
• Biochemistry
• Aging research

Background:

• Protein misfolding and aggregation are hallmarks of age-related diseases.
• Environmental stressors like temperature and oxidative stress can also damage proteins.
• The distinct impacts of aging versus environmental stressors on protein folding remain unclear.

Purpose of the Study:

• To investigate whether aging and environmental stressors affect protein folding similarly or distinctly.
• To characterize the nature of protein aggregates formed under different stress conditions.
• To explore the genetic regulation of stress-induced protein aggregation.

Main Methods:

• Utilized polyQ reporters in Caenorhabditis elegans and mammalian cell culture to monitor protein folding.
• Applied various environmental stressors, including osmotic stress, temperature, and oxidative stress.
• Employed morphological, biophysical, cell biological, and biochemical analyses to compare protein aggregates.
• Investigated the roles of insulin-like growth factor signaling (daf-2) and osmotic stress response mutants.

Main Results:

• Osmotic stress, unlike other proteotoxic stressors, rapidly induced cytoplasmic polyQ aggregation within minutes.
• Osmotic stress-induced aggregates exhibited unique characteristics distinguishing them from aging-induced aggregates.
• The daf-2 mutation, known to inhibit age-related aggregation, did not prevent stress-induced aggregation.
• Mutations enhancing osmotic stress resistance significantly inhibited osmotic polyQ aggregate formation.

Conclusions:

• In vivo, the same protein can form distinct aggregation states based on the initiating stressor.
• Aging and environmental stress impact the proteome through related but separate mechanisms.
• Specific genetic pathways, like the osmotic stress response, can modulate stress-induced protein aggregation.