The Versatile Roles of Exosomes in Neurodegenerative Disorders: From Pathological Mechanism and Diagnostic Biomarkers to Therapeutic Application.

Neurodegenerative diseases are characterized by cognitive or motor impairments resulting from the progressive degeneration of neurons or myelin sheaths. Currently, the majority of these disorders remain incurable, leading to significant detriments in patients' quality of life and imposing substantial economic burdens. Exosomes are a type of extracellular vesicles secreted by cells into the extracellular space, typically range from 30 to 150 nanometers in diameter. These vesicles have been identified in a variety of cell types and can participate in various physiological and pathological processes, including intercellular transport of biomolecules, signal transduction, immune modulation, tissue repair, facilitation of tumor metastasis, and evasion of immune surveillance by cancer cells. In recent years, the potential applications of exosomes in neurodegenerative diseases have garnered increasing attention. Their roles encompass early diagnostic biomarker functions, vehicles for drug delivery and therapeutic agents, mediators in the propagation of pathogenic proteins, and regulators of neuroinflammatory responses. In this review, we try to aims to synthesize recent progress in exosome isolation techniques, elucidate the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD), and examine the diagnostic and therapeutic applications of exosomes within these conditions. Furthermore, it addresses current limitations in exosome-based applications and explores potential strategies to overcome these challenges. The insights of this review may provide the research directions and guidance for future related researchers in these fields.