Effective enrichment of urinary exosomes by polyethylene glycol for RNA detection

Abstract

Urinary exosome is a kind of extracellular vesicles secreted by the cells of kidney and urinary tract. It is an ideal non-invasive biomarker for obtaining information about the state of renal cells. There are few exosomes in urine which are affected by many factors. Enriching exosomes in urine with inexpensive and efficient method is a major challenge. Because exosomes are virus-sized minuscule membrane vesicles or sacs and people used to enrich virus by Polyethylene Glycol (PEG), here we use PEG to enrich the exosomes in urine of 17 volunteers. To confirm the harvest of exosomes, the morphology of exosomes were observed by Transmission Electron Microscopy (TEM), the common exosomal protein markers (CD63, CD9, tumor susceptibility gene 101, Flotillin-1 and β-actin) were detected by Western blot, and the size distribution was analysed by Malvin Nano-ZS. Next, the exosomal housekeeping gene of miRNA (SnRNA-U6) and mRNA (β-actin) were tested by qRT-PCR to prove that this method could be used in subsequent experiments.