Longitudinal stability of urinary extracellular vesicle protein patterns within and between individuals

Abstract

The protein content of urinary extracellular vesicles (EVs) is considered to be an attractive non-invasive biomarker source. However, little is known about the consistency and variability of urinary EV proteins within and between individuals over a longer time-period. Here, we evaluated the stability of the urinary EV proteomes of 8 healthy individuals at 9 timepoints over 6 months using data-independent-acquisition mass spectrometry. The 1802 identified proteins had a high correlation amongst all samples, with 40% of the proteome detected in every sample and 90% detected in more than 1 individual at all timepoints. Unsupervised analysis of top 10% most variable proteins yielded person-specific profiles. The core EV-protein-interaction network of 516 proteins detected in all measured samples revealed sub-clusters involved in the biological processes of G-protein signaling, cytoskeletal transport, cellular energy metabolism and immunity. Furthermore, gender-specific expression patterns were detected in the urinary EV proteome. Our findings indicate that the urinary EV proteome is stable in longitudinal samples of healthy subjects over a prolonged time-period, further underscoring its potential for reliable non-invasive diagnostic/prognostic biomarkers.

Urinary extracellular vesicles as a source of protein‐based biomarkers in feline chronic kidney disease and hypertension

“…Therefore, the values available for comparison of individual proteins between categories were frequently smaller than the total category size. In addition, numerous factors are known to contribute to interindividual differences in uEV proteome in humans, including age and sex, and it is possible that similar confounding factors exist in feline patients (Turco et al 2016, Erozenci et al 2021.…”

Exploring the role of urinary extracellular vesicles in kidney physiology, aging, and disease progression

“…A recent study investigated the stability of urinary EV protein content between healthy subjects over a period of 6 mo. Even if the study involved few subjects (8 healthy individuals), results are informative and comprehensive, due to the use of a highly reproducible next-generation proteomic approach ( 36 ). The majority of identified proteins displayed high correlation among all samples, presenting 40% of the proteome identified in every sample ( 36 ).…”

“…Even if the study involved few subjects (8 healthy individuals), results are informative and comprehensive, due to the use of a highly reproducible next-generation proteomic approach ( 36 ). The majority of identified proteins displayed high correlation among all samples, presenting 40% of the proteome identified in every sample ( 36 ). The study confirms the intra- and interindividual stability of EV proteome ( 36 ).…”

“…The majority of identified proteins displayed high correlation among all samples, presenting 40% of the proteome identified in every sample ( 36 ). The study confirms the intra- and interindividual stability of EV proteome ( 36 ). This result is in line with previous studies, focused on lower protein numbers, describing a low grade of variability among samples and the presence of a stable protein core ( 37 , 38 ).…”

“…Similarly, proteins involved in androgen and spermatogenesis pathways were overrepresented in males. uEVs from females were enriched of proteins involved in hypoxia, coagulation, and angiogenesis, suggesting a connection with the reproductive system ( 36 ) ( Fig. 2 ).…”