MicroRNA-29c in urinary exosome/microvesicle as a biomarker of renal fibrosis

Micro (mi)RNAs are frequently dysregulated in the development of renal fibrosis. Exosomesare small membrane vesicles that could be isolated from urine secreted from all nephronsegments. Here we sought to observe for the first time whether miRNA in urine exosomecould serve as a potential biomarker of renal fibrosis. Urine samples were collected from 32 chronic kidney disease (CKD) patients who underwent kidney biopsy and 7 controls. Exosomewas isolated and confirmed by immunogold staining of exosomemarker. Members of miR-29, miR-200, and RNU6B as endogenous control were detected by RT quantitative PCR. Electronic microscopy verified a typical shape of exosomewith average size of 65.1 nm and labeled it with anti-CD9 and anti- aquaporin 2antibody. Members of miR-29 and miR-200 are readily measured with reduced levels compared with controls (P < 0.05) and can robustly distinguish CKD from controls[ area underthe curve(AUC) varied from 0.902 to 1 by receiver operating characteristics analysis]. miR-29c...