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Abstract: PO1822

Urine Single-Cell RNA Sequencing in Focal Segmental Glomerulosclerosis Reveals Inflammatory Signatures in Immune Cells and Podocytes

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Latt, Khun Zaw, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
  • Heymann, Jurgen, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
  • Jessee, Joseph H., National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
  • Rosenberg, Avi Z., Johns Hopkins Medicine School of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
  • Eddy, Sean, University of Michigan, Ann Arbor, Michigan, United States
  • Yoshida, Teruhiko, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
  • Zhao, Yongmei, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Chen, Vicky, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Nelson, George W., Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Cam, Margaret, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Kumar, Parimal, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Mehta, Monika, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Kelly, Michael C., Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Kretzler, Matthias, University of Michigan, Ann Arbor, Michigan, United States
  • Winkler, Cheryl Ann, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
  • Kopp, Jeffrey B., National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
Background

Individuals with focal segmental glomerulosclerosis (FSGS) typically undergo kidney biopsy only once, which limits the ability to characterize cell populations within kidney over time.

Methods

We used single cell RNA-sequencing (scRNA-seq) to explore disease-related molecular signatures in urine cells of FSGS subjects. We collected 23 urine samples from 12 FSGS subjects, and captured the urine cells using Chromium Single Cell 3’ Library & Gel Bead Kit v2 (10x Genomics, Pleasanton, CA). We used Seurat package (v2) for single cell analysis, Harmony for batch correction and SingleR for annotation of cell clusters using Encode and Blueprint data. We also used Monocle2 to characterize the pseudotime trajectory of differentiation of FSGS urine monocytes from healthy peripheral blood monocytes.

Results

Using single cell transcriptomic analysis of 23 urine samples from 12 FSGS subjects, we identified immune cells, predominantly monocytes, and renal epithelial cells, including podocytes. Further analysis revealed two subtypes consistent with M1 monocytes (produce pro-inflammatory cytokines, initiate immune response) and M2 monocytes (participate in tissue repair). Shed podocytes in urine showed high expression of marker genes for epithelial-to-mesenchymal transition (EMT). We selected the 16 most highly expressed genes from urine immune cells and 10 most highly expressed EMT genes from urine podocytes as immune and EMT signatures, respectively. Using transcriptomic data from kidney biopsies from the Nephrotic Syndrome Study Network (NEPTUNE), we found that urine cell immune- and EMT-signature genes were more highly expressed in FSGS biopsies compared to minimal change disease biopsies.

Conclusion

The identification of monocyte subsets and podocyte expression signatures in FSGS subjects’ urine samples suggests that urine cell profiling might serve as a diagnostic and prognostic tool in the context of nephrotic syndrome. Further, this approach may aid in the development of novel biomarkers for FSGS and for identifying personalized therapies targeting particular molecular pathways in immune cells and podocytes.

Funding

  • NIDDK Support