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Abstract: SA-PO0712

Spatial Proteomics Pipeline Enabling Single Glomerulus Study of Crescentic Glomerulonephritis

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

  • Merchant, Michael, University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Biederman, Laura, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Barati, Michelle T., University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Gaweda, Adam E., University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Cummins, Timothy, University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Wilkey, Daniel Wade, University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Li, Hong, University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Hata, Jessica Lynn, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Dougherty, Julie, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Wenderfer, Scott E., The University of British Columbia, Vancouver, British Columbia, Canada
  • Hidalgo, Guillermo, Hackensack Meridian Health Inc, Edison, New Jersey, United States
  • Klein, Jon B., University of Louisville School of Medicine, Louisville, Kentucky, United States
  • Gaut, Joseph, Washington University in St Louis School of Medicine, St. Louis, Missouri, United States
  • Smoyer, William E., Nationwide Children's Hospital, Columbus, Ohio, United States
Background

Glomerular crescent formation is characteristic of rapidly progressive glomerulonephritis (RPGN). Current non-specific anti-inflammatory treatments are based on incomplete understanding of the molecular mechanisms governing crescent formation. We hypothesize that spatial proteomics comparing crescentic (CR) to non-crescentic (NCR) glomeruli can reveal differential protein expression patterns valuable to understanding CR disease.

Methods

Stained pediatric renal biopsy sections (2 IgAN, 1 Pauci-immune) were digitally annotated by renal pathologists for directed laser capture microdissection of CR and NCR glomeruli across serial sections. Single CR (n=13) and NCR (n=11) glomerulus samples were analyzed using a directDIA workflow and quantitatively compared by 2-way ANOVA to identify changes related to crescents. Proteomic differences were functionally annotated and integrated with KPMP scRNA-seq data using deep learning (DL) methods to assign cellular sourcing and guide pilot spatial interpretation studies using imaging mass cytometry (IMC).

Results

3,000+ protein groups were detected, 20% were differentially distributed between CR and NCR proteomes. Functional annotation suggested CR-enhanced proteins were associated with increased accumulation of extracellular matrix (ECM) and remodeling, increased ribosomal proteins for protein translation, and increased ER-chaperones and oxidative stress. DL analysis of integrated (proteome:sc-RNAseq) data attributed ECM changes to mesangial and fibroblastic remodeling, while ribosomal presence was attributed to immune cells. IMC analysis for periostin abundance and localization suggested likely mesangial role in cellular/fibrocellular crescents and fibroblastic role in fibrous crescents.

Conclusion

We developed a spatial proteomics research pipeline using DL to study single glomeruli that integrates scRNAseq data and culminates in IMC, to confirm protein abundance and incorporate spatial understanding of stromal cell composition. Our data suggest that crescent formation may proceed along common pathways across GN etiologies. Proteomic differences represent candidate biomarkers for more targeted future treatments of RPGN.

Funding

  • NIDDK Support

Digital Object Identifier (DOI)