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Abstract: PO0526

Transcriptomic Mapping of the Human Kidney Papilla Reveals Myeloid Immune Activation and Matrix Remodeling Pathways in Stone Disease

Session Information

Category: Bone and Mineral Metabolism

  • 401 Bone and Mineral Metabolism: Basic

Authors

  • Canela, Victor Hugo, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Bowen, William S., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Melo ferreira, Ricardo, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Lake, Blue, University of California San Diego, La Jolla, California, United States
  • Zhang, Kun, University of California San Diego, La Jolla, California, United States
  • Jain, Sanjay, Washington University in St Louis, St Louis, Missouri, United States
  • Eadon, Michael T., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Williams, James C., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • El-Achkar, Tarek M., Indiana University School of Medicine, Indianapolis, Indiana, United States
Background

The role of the kidney papilla in the pathophysiology of stone disease remains unclear. The aim of this study was to identify the cellular and molecular determinants of nephrolithiasis by molecular mapping of the stone forming papilla using integrated single nuclear and spatial transcriptomics.

Methods

Renal papillary biopsies were obtained from Calcium oxalate (CaOx) stone formers and reference non-stone formers. Tissue sections were prepared according to Visium (10x Genomics) spatial transcriptomic protocol. Single nucleus RNA sequencing from papillary frozen sections was used to spatially map the signature of specific cell types within the tissue. Data analysis and visualization were performed in R (seurat, ReactomePA, ClusterProfiler) and Loupe browser. In-situ mapping of cell distribution and pathway activation were quantified using 3D immunofluorescence imaging. The levels of select proteins in urine samples were quantified by ELISA.

Results

Genes and pathways associated with reactive oxidative stress, myeloid immune activation and extracellular matrix (ECM) remodeling were significantly upregulated in CaOx biopsies relative to non-stone forming reference. Spatial transcriptomic localized the signature of specific cell types and demonstrated the increased expression of genes from those pathways such as FOS, JUN, SOD2, CCL2, SPP1, MMP7/9 and MGP, particularly in areas within or adjacent to mineralized regions in the stone forming papillae. 3D immunofluorescence imaging confirmed the observed activated stress response and myeloid immune activation using phospo-c-JUN and CD68 staining, respectively. Additionally, the activation of myeloid and ECM remodeling pathways was validated by increased levels of MMP7 and MMP9 in the urine of patients with stone disease compared to healthy controls.

Conclusion

Using integrated transcriptomic and imaging approaches, we demonstrate that the papilla of stone patients is an active site of myeloid immune activation, oxidative stress and matrix remodeling. This immune active state had a molecular profile comparable to atherosclerotic disease. Our studies also uncover potential novel markers for screening and activity assesment of important pathogenic pathways in stone patients.

Funding

  • NIDDK Support