Development of Positron Emission Tomography Radiotracers for Imaging α-Synuclein Aggregates

Neurodegenerative diseases (NDDs) that are characterized by the accumulation of alpha-synuclein (α-syn) aggregates in both neurons and the non-neuronal cells of the brain are called synucleinopathies. The most common synucleinopathies includes Parkinson's disease (PD), Parkinson's disease dementia (PDD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB). Significant progress has been made in the development of positron emission tomography (PET) radiotracers for synucleinopathies, yielding several α-syn tracers that have entered clinical studies. However, selective α-syn imaging still faces inherent challenges. This review provides a comprehensive overview of the progress in α-syn PET radiotracers from three angles: Alzheimer's disease (AD)-derived scaffolds, representative compound scaffolds and analogs, and the identification of α-syn tracers through high-throughput screening (HTS). We discuss the characteristics, advantages, and limitations of the tracers for preclinical and clinical application. Finally, future directions in the development of radioligands for proteinopathies are discussed. There is no clinical available PET radiotracer for imaging α-syn aggregates, but these advances have laid a key foundation for non-invasive α-syn imaging and early diagnosis of synucleinopathies.