Department of Biophysics, All India Institute of Medical Sciences, New Delhi 110029, India.
Department of Biotechnology, Amity University, Mumbai 410206, India.
Int J Mol Sci. 2021 Jan 4;22(1):440. doi: 10.3390/ijms22010440.
Neurodegenerative diseases (ND) remains to be one of the biggest burdens on healthcare systems and serves as a leading cause of disability and death. Alzheimer's disease (AD) is among the most common of such disorders, followed by Parkinson's disease (PD). The basic molecular details of disease initiation and pathology are still under research. Only recently, the role of exosomes has been linked to the initiation and progression of these neurodegenerative diseases. Exosomes are small bilipid layer enclosed extracellular vesicles, which were once considered as a cellular waste and functionless. These nano-vesicles of 30-150 nm in diameter carry specific proteins, lipids, functional mRNAs, and high amounts of non-coding RNAs (miRNAs, lncRNAs, and circRNAs). As the exosomes content is known to vary as per their originating and recipient cells, these vesicles can be utilized as a diagnostic biomarker for early disease detection. Here we review exosomes, their biogenesis, composition, and role in neurodegenerative diseases. We have also provided details for their characterization through an array of available techniques. Their updated role in neurodegenerative disease pathology is also discussed. Finally, we have shed light on a novel field of salivary exosomes as a potential candidate for early diagnosis in neurodegenerative diseases and compared the biomarkers of salivary exosomes with other blood/cerebrospinal fluid (CSF) based exosomes within these neurological ailments.
神经退行性疾病（ND）仍然是医疗系统的最大负担之一，是导致残疾和死亡的主要原因。阿尔茨海默病（AD）是此类疾病中最常见的一种，其次是帕金森病（PD）。疾病起始和病理的基本分子细节仍在研究中。直到最近，外泌体的作用才与这些神经退行性疾病的发生和进展联系起来。外泌体是一种带有双脂质层的小型细胞外囊泡，曾经被认为是一种细胞废物，没有任何功能。这些直径为 30-150nm 的纳米囊泡携带特定的蛋白质、脂质、功能性 mRNAs 和大量非编码 RNA（miRNAs、lncRNAs 和 circRNAs）。由于外泌体的内容物根据其起源和受体细胞而有所不同，因此这些囊泡可以用作早期疾病检测的诊断生物标志物。在这里，我们综述了外泌体及其生物发生、组成和在神经退行性疾病中的作用。我们还提供了通过一系列现有技术对外泌体进行表征的详细信息。还讨论了它们在神经退行性疾病病理中的最新作用。最后，我们探讨了唾液外泌体作为神经退行性疾病早期诊断的潜在候选物的新领域，并将唾液外泌体的生物标志物与这些神经疾病中其他基于血液/脑脊液（CSF）的外泌体的生物标志物进行了比较。
