Abstract: SA-PO683
Urine Exosome Protein Signatures Differentiate Disease Type and Activity in Children with Steroid-Resistant Nephrotic Syndrome
Session Information
- Pediatric Glomerular Disease
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pediatric Nephrology
- 1700 Pediatric Nephrology
Authors
- Bensa, Ivana, University of Heidelberg, Heidelberg, Germany
- Yilmaz, Alev, Istanbul University Faculty of Medicine, Istanbul, Turkey
- Jankauskiene, Augustina, Children's Hospital, affiliate of Vilnius University Hospital Santaros Clinic, Vilnius, Lithuania
- Paripovic, Dusan, University Children's Hospital, Belgrade, Serbia
- Yuruk yildirim, Zeynep, Istanbul University Faculty of Medicine, Istanbul, Turkey
- Schaefer, Franz S., University of Heidelberg, Heidelberg, Germany
- Kratochwill, Klaus, University of Vienna, Vienna, Austria
Group or Team Name
- PodoNet Consortium
Background
Steroid resistant nephrotic syndrome (SRNS) is an etiologically and prognostically heterogeneous condition. In 40-50% of children with SRNS remission is achieved by intensified immunosuppressive (IIS) therapy, 20-25% suffer from hereditary podocytopathies, and 30-40% turn out multidrug resistant (MDR) without an identifiable genetic cause. Long-term renal outcomes are excellent for IIS, poor for genetic, and intermediate for MDR-SRNS. No biomarkers differentiating these entities early in the disease course are available to date. Urinary exosome analysis is a promising non-invasive methodology to obtain information about pathobiological processes in the cells lining the nephron.
Methods
Urine samples were obtained from patients with IIS-SRNS (n=4) and MDR-SRNS with or without an identified genetic cause (n=4 each). IIS patients were studied both during relapse and in remission. Exosomes were isolated by ultracentrifugation followed by size exclusion HPLC. Protein isolates were digested with trypsin and LysC, labeled with isobaric tags (TMT 10-plex) and subjected to two-dimensional LC-MS analysis. Ingenuity software was used to identify enriched pathways and functions.
Results
We identified 2,713 proteins with high confidence in urinary exosomes. Comparison of samples from patients with active disease (IIS-relapse/MDR/genetic) vs remission yielded 739 differentially abundant proteins, respectively, with glomerular and tubular cell damage as the most prominent disease functions. Exosomal fractions from active IIS and MDR/genetic patients differed in 124 proteins (most prominently of complement and coagulation pathways and proteins indicating glomerular and proximal tubule damage), whereas only 16 proteins were differentially abundant in MDR with and without an identified genetic cause. Biomarker filter analysis for individual proteins discriminating between disease states yielded highly significant candidates.
Conclusion
Urinary exosome analysis is technically feasible and provides a reflection of disease-related tissue alterations on the proteome level. The deregulated molecular pathways identified in this study might allow to differentiate etiologically and prognostically distinct entities in SRNS.