Neurotoxic and Neuroprotective Role of Exosomes in Parkinson's Disease

Exosomes are extracellular vesicles produced by eukaryotic cells that are also found in most biological fluids and tissues. While they were initially thought to act as compartments for removal of cellular debris, they are now recognized as important tools for cell-to-cell communication and for transfer of pathogens between cells. They have attracted particular interest in neurodegenerative diseases for their potential role in transferring prion like proteins between neurons, and in Parkinson's disease (PD), they have been shown to spread oligomers of α-synuclein in brain accelerating the progression of this pathology. A potential neuroprotective role of exosomes has also been equally proposed in PD as they could limit the toxicity of α-synuclein by clearing them out of the cells. Exosomes have also attracted considerable attention for use as drug vehicles; being non-immunogenic in nature, they provide an unprecedented opportunity to enhance delivery of incorporated drugs to target cells. In this review, we discuss current knowledge about the potential neurotoxic and neuroprotective role of exosomes, and their potential application as drug delivery systems in PD.