Abstract: SA-PO0759
Quantitative Proteomic Analyses of Podocyte Injury in Steroid-Resistant Nephrotic Syndrome (SRNS) vs. Steroid-Sensitive Nephrotic Syndrome (SSNS)
Session Information
- Glomerular Diseases: Profiling Through Multiomics
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Cummins, Timothy, University of Louisville School of Medicine, Louisville, Kentucky, United States
- Kamigaki, Yu, Nationwide Children's Hospital, Columbus, Ohio, United States
- Dougherty, Julie, Nationwide Children's Hospital, Columbus, Ohio, United States
- Klein, Jon B., University of Louisville School of Medicine, Louisville, Kentucky, United States
- Smoyer, William E., Nationwide Children's Hospital, Columbus, Ohio, United States
Background
The cause of idiopathic nephrotic syndrome (INS) remains unknown but is thought to involve immune dysregulation, systemic circulating factors, or inherited podocyte structural abnormalities. Most studies identify podocytes as the target cell of injury in INS. We thus hypothesized that the molecular mechanism of podocyte injury in patients with SSNS could be differentiated from those with SRNS.
Methods
We treated immortalized human podocytes with 4% sera from new onset, pre-treatment SSNS and SRNS patients. Mass spectrometry analyses of cell lysates at 3 hr post-treatment identified changes in the podocyte proteome between sera from SSNS vs. SRNS patients. Multidimensional reduction and univariate analyses illustrated differences in proteome abundance and highlighted individual abundance changes. Treated podocytes were also analyzed for cellular stress (LDH release) at 24 h and assayed for viability (XTT assay) at 72 h.
Results
Higher abundance of the nucleoporin NUP93 was seen in podocytes treated with SSNS vs. SRNS patient sera, while higher abundances of STOML3, CBX3, PARK7, RAB1A, RAB18, and ERLIN2 were seen in podocytes treated with SRNS vs. SSNS patient sera. Podocytes exposed to SRNS patient sera also showed significantly increased cellular stress (P=0.03) and significantly decreased cell viability (P=0.004) vs. untreated control cells, and trends toward higher stress and lower viability vs. cells treated with SSNS patient sera, although these differences were not significant.
Conclusion
These data reveal disparate molecular signatures of podocyte injury caused by SRNS vs. SSNS patient sera. Also, in vitro assays demonstrated increased toxicity of SRNS vs. SSNS patient sera to podocytes. Loss of function mutations in NUP93 (involved in in nucleocytoplasmic transport and cell function) have been associated with SRNS and FSGS. Also, the podocyte proteins with higher abundance after treatment with SRNS vs. SSNS patient sera have been reported to play critical roles in glomerular filtration barrier, integrity, mesangial signaling, oxidative stress, and protein homeostasis. Ongoing analyses of podocyte phosphoproteomic enrichment may identify additional mechanistic differences in injury induced by SRNS vs. SSNS patient sera.
Funding
- Private Foundation Support