You are here:
Urinary MicroRNA Biomarkers of Nephrotoxicity Demonstrate Reduced Variability and Directionality in Exosomal Compared to Whole Fractions
Citation:
Chorley, B., T. Sharapova, T. Tsuji, P. Yuen, P. Mahalingaiah, C. Mitchell, AND S. Pettit. Urinary MicroRNA Biomarkers of Nephrotoxicity Demonstrate Reduced Variability and Directionality in Exosomal Compared to Whole Fractions. 13th International Conference on Environmental Mutagens, Ottawa, CANADA, August 27 - September 01, 2022. https://doi.org/10.23645/epacomptox.20384181
Impact/Purpose:
The abstract is for a presentation to be given at the 13th International Conference on Environmental Mutagens in Ottawa, Canada, Aug 27 - Sept 1. This work demonstrates the utility of microRNA measurements in the urine to detect mild to moderate nephrotoxicity in a longitudinal animal study. The work is novel as very few studies have utilized these measurements contained in the exosome fraction, which we show reduces variability compared to whole urine. This work was done in collaboration the HESI eSTAR members of the miRNA working group.
Description:
MicroRNAs (miRNAs) are small non-coding RNA that are remarkably stable in biofluids and viewed as promising biomarkers of kidney injury that can complement current protein biomarkers. However, miRNA data obtained from whole urine lacks consistency, especially in human or large animal species. We hypothesized that the variability measured in whole urine samples may be reduced by examining miRNA contained only within the exosomal fraction. In our study, we utilized urine samples collected from monkeys exposed to 200 and 300 ug/kg of a tool compound 1 and total 12 weeks and with confirmed renal toxicity confirmed by histopathology. Exosomes were isolated by ultracentrifugation and counted and sized using nanoparticle tracking analysis. Candidate miRNAs (miRs-210-3p, 423-5p, 143-3p, 130b-3p, 486-5p, 193a-3p) were measured using real-time LNA SYBR Green PCR. The miRNA panel was selected based on pilot data from whole urine which exhibited high animal-to-animal variability in miRNA dynamics as well as low correlation with histopathologic severity. Exosomal miRNA measurements still exhibited variability, however normalizing measurements to exosomal counts reduced measured coefficient of variation by a factor of 2 (249.8% unnormalized versus 123.7% normalized). In addition, we noted significant attenuation (t-test p-value<0.05) of urinary exosomal miRs-210-3p and 143-3p by 12 weeks of exposure when using exosomal normalized measures. This contrasts with the trending increased miRNAs previously measured in the whole urine. The mechanisms of packaging of these miRNAs may therefore be influenced by renal toxicity and demonstrate a more refined, less variable signal, than those measured in whole urine.
URLs/Downloads:
DOI: Urinary MicroRNA Biomarkers of Nephrotoxicity Demonstrate Reduced Variability and Directionality in Exosomal Compared to Whole Fractions