Large-Scale Proteomic Assessment of Urinary Extracellular Vesicles Highlights Their Reliability in Reflecting Protein Changes in the Kidney

Abstract

Background: Urinary extracellular vesicles (uEVs) are secreted into urine by cells from the kidneys and urinary tract. Although changes in uEV proteins are used for quantitative assessment of protein levels in the kidney or biomarker discovery, whether they faithfully reflect (patho)physiological changes in the kidney is a matter of debate. Methods: Mass spectrometry was used to compare in an unbiased manner the correlations between protein levels in uEVs and kidney tissue from the same animal. Studies were performed on rats fed a normal or a high K+ diet. Results: Absolute quantification determined a positive correlation (Pearson R=0.46 or 0.45, control or high K+ respectively, p<0.0001) between the ~ 1000 proteins identified in uEVs and corresponding kidney tissue. Transmembrane proteins had greater positive correlations relative to cytoplasmic proteins. Proteins with high correlations (R>0.9), included exosome markers Tsg101 and Alix. Relative quantification highlighted a monotonic relationship between altered transporter/channel abundances in uEVs and the kidney following dietary K+ manipulation. Analysis of genetic mouse models also revealed correlations between uEVs and kidney. Conclusion: This large-scale unbiased analysis identifies uEV proteins that track the abundance of the parent proteins in the kidney. The data form a novel resource for the kidney community and support the reliability of using uEV protein changes to monitor specific physiological responses and disease mechanisms.

Acute Intravenous NaCl and Volume Expansion Reduces Sodium-Chloride Cotransporter Abundance and Phosphorylation in Urinary Extracellular Vesicles

“…uEVs are a tool to assess renal epithelial cell function in humans. 7,11 A recent large-scale unbiased analysis identified uEV proteins that track the abundance of the parent protein in the kidney, 12 further supporting the reliability of using uEV protein changes to monitor specific physiological responses and disease mechanisms.…”

Generation and analysis of pseudohypoaldosteronism type II knock‐in mice caused by a nonsense KLHL3 mutation in the Kelch domain

“…They have become a promising source for investigations on pathogenesis and can be used instead of invasive tissue or liquid biopsy 51,52 . A recent study showed that uEV protein changes are reliable for monitoring specific physiological responses and disease mechanisms 50 . The present study is the first to validate Spak‐Ncc activation via uEVs isolated from a nonsense Klhl3 mutation‐causing PHAII mouse model.…”

“…Notably, uEVs constitute a potential source of molecular biomarkers of kidney diseases such as Bartter syndrome, GS, primary aldosteronism, polycystic kidney disease, and nephrogenic diabetes insipidus. 50 They have become a promising source for investigations on pathogenesis and can be used instead of invasive tissue or liquid biopsy. 51,52 A recent study showed that uEV protein changes are reliable for monitoring specific physiological responses and disease mechanisms.…”

“…Even though the results of IB and IF consistently show that Wnks have hegemony in regulating Spak‐N(k)cc activation in Klhl3 W523X /+ mice, transgenic mice should be euthanized to obtain biologically pertinent information. Notably, uEVs constitute a potential source of molecular biomarkers of kidney diseases such as Bartter syndrome, GS, primary aldosteronism, polycystic kidney disease, and nephrogenic diabetes insipidus 50 . They have become a promising source for investigations on pathogenesis and can be used instead of invasive tissue or liquid biopsy 51,52 .…”

Urinary Extracellular Vesicles Are a Novel Tool to Monitor Allograft Function in Kidney Transplantation: A Systematic Review

“…For example, the proteins in uEV are predominantly (99.96%) derived from the kidney and urinary tract [12]. Moreover, the changes in protein expression in kidneys are reliably assessed by the proteome of uEV [13].…”