Diagnostic and Therapeutic Potential of Exosomal MicroRNAs for Neurodegenerative Diseases.

Neurodegenerative disorders (NDs) are characterized by a gradual loss of neurons and functions that eventually leads to progressive neurological impairment. In view of the heavy burden on the healthcare system, efficient and reliable biomarkers for early diagnosis and therapeutic treatments to reverse the progression of NDs are in urgent need. There has been an increasing interest in using exosomal miRNAs as biomarkers or targeted therapies for neurological diseases recently. In this review, we overviewed the updated studies on exosomal miRNAs as biomarkers and potential therapeutic approaches in NDs, as well as their association with the pathophysiology of this group of disorders, especially Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). The exosomal miRNAs that are commonly dysregulated across different NDs or are commonly used as therapeutic candidates were also identified and summarized. In summary, the feasibility of exosomal miRNAs as biomarkers and potential targeted therapy for NDs has been verified. However, due to the limitations of existing studies and the discrepancies across different studies, high quality laboratory and clinical investigations are still required.