Current Understanding of Protein Aggregation in Neurodegenerative Diseases

Protein aggregates are central to the pathogenesis of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. This comprehensive review explores the mechanisms of protein misfolding and aggregation, their prion-like propagation, and the critical role of oligomeric species in neurotoxicity. It further examines cellular clearance pathways, including the ubiquitin-proteasome system and autophagy, alongside the regulatory functions of molecular chaperones. The review also covers advanced diagnostic imaging and biomarker techniques, as well as emerging therapeutic strategies such as pharmacological agents, gene therapy, and immunotherapy. Controversies regarding the toxicity of aggregates and future directions, including novel degradation technologies and targeted therapeutic approaches, are discussed. By integrating current knowledge, this review aims to provide a broad yet detailed overview of the field, highlighting both established concepts and promising avenues for research and treatment.