Targeted protein degradation: expanding the technology to facilitate the clearance of neurotoxic proteins in neurodegenerative diseases.

In neurodegenerative diseases (NDDs), disruptions in protein homeostasis hinder the clearance of misfolded proteins, causing the formation of misfolded protein oligomers and multimers. The accumulation of these abnormal proteins results in the onset and progression of NDDs. Removal of non-native protein is essential for cell to maintain proteostasis. In recent years, targeted protein degradation (TPD) technologies have become a novel means of treating NDDs by removing misfolded proteins through the intracellular protein quality control system. The TPD strategy includes the participation of two primary pathways, namely the ubiquitin-proteasome pathway (for instance, PROTAC, molecular glue and hydrophobic tag), and the autophagy-lysosome pathway (such as LYTAC, AUTAC and ATTEC). In this review, we systematically present the mechanisms of various TPD strategies employed for neurotoxic protein degradation in NDDs. The article provides an overview of the design, in vitro and in vivo anti-NDD activities and pharmacokinetic properties of these small-molecular degraders. Finally, the advantages, challenges and perspectives of these TPD technologies in NDDs therapy are discussed, providing ideas for further development of small molecule degraders in the realm of NDDs.