Chronic kidney disease (CKD) is a major global health burden leading to a loss of kidney function via podocyte damage, a non-regenerative renal cell type. Early detection of podocyte injury is crucial but remains limited, highlighting the need for non-invasive biomarkers. Therefore, we analysed urinary exosomal microRNAs (miRNAs) in relation to podocyte morphology in biopsies from 65 CKD patients, including focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD) and healthy controls. Global profiling distinguished CKD patients from controls, with miR-606 consistently upregulated and miR-431 downregulated. In podocytopathies, MCD displayed a predominantly suppressed miRNA profile, with miR-141, miR-429, and miR-660 as key candidates, whereas FSGS exhibited elevated miR-181c, miR-3610, miR-663b, miR-4651, and miR-429. Super-resolution morphometry revealed diffuse foot process effacement in MCD and heterogeneous, focally disrupted architecture in FSGS, providing a structural context for the molecular findings. Regression analyses linked these miRNAs to filtration slit density and length, proteinuria, and 25-Hydroxy-vitamin-D3 levels, integrating molecular, structural, and clinical readouts. These results define a coherent miRNA signature of podocyte injury that distinguishes CKD entities and correlates molecular changes with disease severity. Combining urinary exosomal miRNAs with morphometric analysis facilitates early, non-invasive identification of podocyte damage, enabling earlier therapeutic intervention in podocytopathies.

DNA-binding protein A (DbpA) belongs to the Y-box family of cold shock domain (CSD) proteins that bind RNA/DNA and exert intracellular functions in cell stress, proliferation, and differentiation. Given the pattern of DbpA staining in inflammatory glomerular diseases, without adherence to cell boundaries, we hypothesized extracellular protein occurrence and specific functions. Lipopolysaccharide and ionomycin induce DbpA expression and secretion from melanoma and mesangial cells. Unlike its homologue Y-box-binding protein 1 (YB-1), DbpA secretion requires inflammasome activation, as secretion is blocked upon the addition of a NOD-like receptor protein-3 (NLRP3) inhibitor. The addition of recombinant DbpA enhances melanoma cell proliferation, migration, and competes with tumor necrosis factor (TNF) binding to its receptor (TNFR1). In TNF-induced cell death assays, rDbpA initially blocks TNF-induced apoptosis, whereas at later time points (>24 h), cells are more prone to die. Given that CSD proteins YB-1 and DbpA fulfill the criteria of alarmins, we propose that their release signals an inherent danger to the host. Some data hint at an extracellular complex formation at a ratio of 10:1 (DbpA:YB-1) of both proteins.