TABLE 2.

The study of exosome contents in PD biomarkers.

Molecule	Object	Source	Expression	Potential target/mechanism	Results	References
miR-19b miR-195,miR-24	Human	serum	Down Up	Parkin RBR E3 ubiquitin protein ligase (miR-19b), LRRK2/PARK8 (miR-19b), and ATP13A2/PARK9 (miR-24 and miR-195).	ROC curve was used to evaluate the combined diagnostic value of the three miRNAs: AUC was 0.946 (95%CI, 0.910-0.981).	Cao et al., 2017
miR-153, miR-409-3p, miR-10a-5p, let-7g-3p miR-1 and miR-19b-3p	Human	CSF	Up Down	Neurotrophin signaling, mTOR signaling, Ubiquitin mediated proteolysis, Dopaminergic synapse, Glutamatergic synapse were the most prominent pathways	The sensitivity and specificity for distinguishing Parkinson’s disease from control were 94% for miR-1, 93% for miR-153, 90% for miR-409-3p, 94% for miR-19b-3p, 95% for miR-10a-5p, and 95% for let-7g-3p.	Gui et al., 2015
miR-505 miR-331-5p	Human	serum	Down Up	−	The ROC curve analysis AUC values of miRNA-331-5p and miR-505 were 0.849 and 0.898, respectively.	Yao et al., 2018
prion protein	Human	serum	Up	PrPC can increase phosphorylated α-synuclein and induce synaptic damage and calcium homeostasis.	The level of prion protein in PD plasma exosomes was significantly correlated with the level of cognitive impairment. (t = -3.185, P = 0.001)	Leng et al., 2020
DJ-1	Human	serum	Up	DJ-1 can promote disease progression by regulating α-synuclein cytotoxicity.	The ROC analysis results of DJ-1 in PD plasma neurogenic exosomes were as follows: AUC = 0.703, sensitivity = 79.5%, specificity = 57.5%.	Zhao et al., 2018