Aging neurons face a unique challenge: they must manage their waste disposal while maintaining their function. A recent study reveals that synaptic proteins in aged mice degrade more slowly than in younger mice, leading to potential toxic buildup. This study, published in Nature, is the first to specifically examine protein clearance in neurons of living animals. The findings suggest that neurons may outsource their waste disposal to microglia, but this process could become toxic as microglia age. The research also highlights the importance of protein turnover in neurons, with a focus on the axon's role in protein degradation. The study's technical achievement lies in tracking protein degradation and aggregation in neuronal cells, revealing that many destruction-resistant proteins are involved in synaptic function. As protein aggregation increases with age, it clogs the degradation machinery, leading to a complex interplay between neurons and microglia. The study's findings raise questions about the balance between neuronal waste production and microglia's ability to manage it, with potential implications for neurodegenerative diseases.
