Employing extracellular vesicles for non-invasive renal monitoring: A captivating prospect

Abstract

Extracellular vesicles (EVs) are fascinating nano-sized subjects extensively studied over the recent years across several disparate disciplines. EVs are endlessly secreted into the extracellular microenvironment by most cell types under physiological and pathological conditions. EVs encompass a variety of molecular constituents from their cell of origin, such as lipids, cell specific proteins and RNAs, thus constituting an informative resource for studying molecular events at the cellular level. There are three main classes of EVs classified based on their size, content, biogenesis and biological functions: exosomes, shedding microvesicles and apoptotic bodies. Besides cell culture supernatants, biological fluids have also been shown to contain different types of EVs. Amongst the various body fluids, the study of urinary extracellular vesicles (uEVs) as a source of candidate biomarkers gained much attention, since: (1) urine can be non-invasively collected in large amounts; and (2) the isolated uEVs are stable for a relatively long period of time. Here, we review the important aspects of urinary extracellular vesicles which are fast gaining attention as a promising future tool for the non-invasive monitoring of urinary tract. Recent advancements in the purification and analysis of uEVs and collection of their constituents in rapidly developing public databases, allow their better exploitation in molecular diagnostics. As a result, a growing number of studies have shown that changes in expression profile at the RNA and/or protein levels of uEVs reveal the molecular architectures of underlying key pathophysiological events of different clinically important diseases with kidney involvement.

Keywords: Urine analysis, Extracellular vesicles, Biomarkers, Kidney disease, Quantitative proteomics, Exosomes

Core tip: Urinary extracellular vesicles research is a fast growing field of biomarker discovery providing new attracting prospective for monitoring tissue alteration in easily accessible clinical samples. Over the past ten years intense research has identified the various urinary vesicular cargo molecules (i.e., RNAs, proteins and lipids) and detected their alterations upon a number of renal diseases. With the number of diseases relating to kidney increasing it is essential to effectively utilize this invaluable tool for the early diagnosis. Here we provide a comprehensive overview of uEVs nicely setting the stage for their utility in future clinical diagnostics.