Isolation of human serum exosome and the clinical value of exosomal miRNA detection
10.3760/cma.j.issn.1009-9158.2015.08.013
- VernacularTitle:人血清 Exosome 的分离及其 miRNA 检测的临床价值
- Author:
Zhuo LI
;
Wei KANG
;
Rui LI
;
Xiaoke HAO
;
Yueyun MA
- Publication Type:Journal Article
- Keywords:
Exosome;
Serum;
miRNA
- From:
Chinese Journal of Laboratory Medicine
2015;(8):557-561
- CountryChina
- Language:Chinese
-
Abstract:
Objective To isolate and identify exosomes from human serum , explore the feasibility of detecting exosomal miRNA in human serum.Methods Retrospective study.Serum samples from 10 healthy individuals in January 2013 were randomly selected.Besides, from January 2013 to December 2014, serum samples from prostate cancer(PCa) patients (n=20), benign prostatic hyperplasia(BPH) patients ( n=20 ) and healthy controls ( n=20 ) were selected.Exosomes were isolated from these serum samples using ExoQuick , and then identified by using transmission electron microscopy , NanoSight nano particle analyzer and Western Blot for morphology and molecular phenotype.The quality of exosomal RNA was analyzed using Agilent 2100 Bioanalyser.Then quantificational real-time polymerase chain reaction ( qRT-PCR) was carried out to detect miRNAs in different components of human serum ,and nonparametric tests were used for difference analysis.Results Exosomes isolated from human serum showed round or oval vesicles, mainly in diameter 40-100 nm, and with maximum peak distribution of 58 nm.Moreover, they expressed HSP70 and four transmembrane protein CD 63.Agilent 2100 Bioanalyzer results showed that the major RNA component of exosome was about 25nt small RNA.qRT-PCR confirmed that 4 normal miRNAs were expressed in human serum exosome , and the expression of miRNAs in exosome pellets were higher than the whole serum (miR-21, U =16,P =0.007 2; miR-16, U =3,P<0.000 1; miR-20a, U =2,P <0.000 1;let-7a, U=13,P=0.003 2) and exosome-depleted supernatant ( miR-21, U=15,P=0.006 5;miR-16, U=2,P<0.000 1;miR-20a, U=1,P<0.000 1;let-7a, U=10,P=0.002 8).miR-141, the molecular marker of prostate cancer ,were analyzed by qRT-PCR in whole serum samples and serum exosome pellets isolated from the same serum in a cohort of 20 PCa patients , 20 BPH patients and 20 healthy control people.The results showed that , in three groups , exosomal miR-141 expression were all significantly higher than serum circulating miR-141 (Control group, U=66,P=0.000 3; BPH group, U=83,P=0.001 6;PCa group, U=54,P<0.000 1).In addition, the expreession of exosomal miR-141 in PCa patients was significantly higher than BPH patients or healthy controls (3.85 fold, U=74,P=0.000 7 and 4.06 fold, U=70,P=0.000 5).Conclusion Exosome can be efficiently isolated from human serum.Compared with the whole serum , isolation of serum exosome may helpful to improve the detection of circulating miRNA.
