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Abstract: TH-PO419

Single Nuclei RNA-Seq Reveals Cell-Type Specific Responses to Disease and Enalapril in the gddY Mouse Model of IgA Nephropathy

Session Information

Category: Glomerular Diseases

  • 1301 Glomerular Diseases: Fibrosis and Extracellular Matrix

Authors

  • Olson, N. Eric, Chinook Therapeutics Inc, Seattle, Washington, United States
  • Mcconnell, Mark, Chinook Therapeutics Inc, Seattle, Washington, United States
  • McCown, Phillip J., University of Michigan, Ann Arbor, Michigan, United States
  • Otto, Edgar A., University of Michigan, Ann Arbor, Michigan, United States
  • Nair, Viji, University of Michigan, Ann Arbor, Michigan, United States
  • Gunawan, Marvin, Chinook Therapeutics Inc, Seattle, Washington, United States
  • Eddy, Sean, University of Michigan, Ann Arbor, Michigan, United States
  • Cox, Jennifer H., Chinook Therapeutics Inc, Seattle, Washington, United States
  • Kretzler, Matthias, University of Michigan, Ann Arbor, Michigan, United States
  • Kano, Toshiki, Juntendo University Faculty of Medicine, Tokyo, Japan
  • Suzuki, Yusuke, Juntendo University Faculty of Medicine, Tokyo, Japan
  • King, Andrew J., Chinook Therapeutics Inc, Seattle, Washington, United States
Background

IgA nephropathy (IgAN) is defined by the deposition of IgA-containing immune complexes in the mesangium that induce kidney injury. To better understand the mechanisms of IgAN progression and cellular response to ACE inhibitor enalapril (ACEi) we performed snRNA-seq of kidney cortex from control mice, gddY mice, a spontaneous IgAN model and gddY mice treated with ACEi for 8 weeks.

Methods

Nuclei from naive (n=6), gddY (n=8), and ACEi-treated gddY mice (n=8) were isolated from kidney cortex and sequenced using the 10x Genomics Platform and analyzed using Seurat 4.0. QC filters were applied and nuclei were used to identify significant differentially expressed genes (DEGs) (|log FC|≥0.25, p-adj≤0.05). DEGs for each cell type were identified by comparing gddY vs. naive, or gddY vs. ACEi-treated gddY mice. Ligand/Receptor (L/R) analysis was performed using Connectome.

Results

After QC filters were applied, 152,059 nuclei remained, resulting in good representation across all major kidney cell types. We identified failed repair (FR) proximal tubule cells as the most expanded kidney cell type in gddY (5.6-fold) with the highest number of DEGs (779) compared to naive mice; the number of mesangial cells, fibroblasts, and endothelial cells also increased in gddY mice. FR cells showed a Tnf activation signature induction. L/R analysis shows FR cells are a source of Tnf stimulation for fibroblasts and Ccl2 stimulation of leukocytes.

The response to ACEi, measured by gene expression changes, varied widely across kidney cell types. Ascending thin limb cells showed the smallest gene expression changes with 7 DEGs and VSMC/Pericytes showed the greatest gene expression changes with 377 DEGs. FR cells showed a modest response to ACEi, with 170 DEGs. When we compared gene expression changes after ACEi with those dysregulated in the gddY model, we found ACEi primarily induced de novo gene expression. For VSMC/P, 32 genes were reversed while 320 showed de novo expression with ACEi treatment compared to untreated gddY.

Conclusion

This study provides novel cell-type specific molecular insights into the pathogenesis of glomerulonephritis and subsequent tubular injury and identified cell-type specific differences in response to ACEi in an IgAN mouse model.

Funding

  • Commercial Support