Abstract Nephrotic syndrome (NS) is a common childhood glomerulopathy characterized by significant proteinuria but lacks reliable biomarkers of relapse or prognosis. Extracellular vesicles (EVs) are membrane-bound particles released from stressed cells that carry molecular cargo reflective of cellular state. We previously demonstrated increased podocyte-specific urinary EVs in children with NS during relapse, with levels returning to near-zero during remission. Building on this observation, we evaluated puromycin aminonucleoside (PAN) injury by characterizing proteomic signatures of podocytes and their EVs in vitro. In parallel, we performed proteomics on urinary EVs from children with active NS and those in remission, enabling comparison between experimental and clinical EV proteomes. PAN-injured podocytes demonstrated increased production of large EVs (LEV) and distinct alterations in both cellular and LEV proteomes. Similar proteomic changes were observed in urinary LEVs from children with active NS. Urinary LEV proteomes differed markedly between disease and remission, with 645 proteins unique to disease and 240 to remission, including enrichment of solute carrier transport proteins. Several proteins showed concordant regulation across experimental and clinical datasets, including increased STX3, RPN2 and DCTN1 and decreased HSPA9 and PCYT2, providing a basis for studying EV-derived biomarkers of disease activity in paediatric NS.
Cooper et al. (Wed,) studied this question.