Extracellular Vesicles as Biomarkers for Neurodegenerative Diseases

Abstract

For the development of therapies for neurodegenerative diseases, it is essential to have validated biomarkers for diagnosis and monitoring disease progression. Finding relevant biomarkers is difficult because molecules secreted by the cell types involved in neurodegenerative diseases are often diluted and unstable in body fluids such as cerebrospinal fluid and blood. For this purpose, extracellular vesicles (EVs) may be of use. EVs are small particles that are comprised of a membrane which envelops cell-derived biomolecules. EVs are secreted by all cell types, and cargo found in EVs varies according to their origin. EV cargo may reflect the pathological state of central nervous system (CNS) specific cell types in neurodegenerative diseases. EVs from CNS specific cell types can be isolated from body fluids, making EVs a promising tool to detect pathological changes in neurodegenerative diseases. This review explores the present evidence for the use of extracellular vesicle cargo as potential biomarkers for neurodegenerative diseases such as amyotrophic lateral sclerosis, Huntington’s disease, and Parkinson’s disease. Evidence is revised on several disease-associated proteins and RNAs that may be used to diagnose neurodegenerative diseases and monitor disease progression during clinical trials. Further validation and standardization are needed.