ABSTRACT
Objective To isolate and identify exosomes from serum samples of the patients with polymyositis / dermatomyositis (PM/ DM),and analyze their protein composition preliminarily.Methods Exosomes from serum samples of the patients with PM/DM were isolated and purified by the ExoQuickTM kit.The morphological characteristics and particle size of exosomes were determined by transmission electron microscope (TEM) and NanoSight analyzer,respectively.The surface markers of exosomes such as CD9,CD81 and Flotillin-2 were identified by western blot.The concentration and composition of exosome protein were determined by the BCA method and SDS-PAGE,respectively.Results The exosomes from serum samples of PM/DM patients displayed round or oval vesicles with membrane structure under TEM,and their diameter range was about (92 ± 67) nm.western blot showed that these exosomes expressed CD9,CD81 and Flotillin-2.The total protein concentrations of exosomes in the patients with PM/DM and healthy controls were 14.68 (6.00,32.55) μg/μL and 14.09 (8.00,23.28) μg/μL,respectively.SDS-PAGE showed that high-abundance proteins enriched in 55-70 kD in both PM/DM patients and healthy controls,and that there were different bands in 40-55 kD between them.Conclusion Exosomes are isolated from serum samples of the patients with PM/DM successfully,and their protein concentration and composition are analyzed preliminarily,which provides the experimental evidences for further finding differential proteins.