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Abstract: SA-PO744

Single Cell RNA Sequencing Revealed Genes That Could Mediate Podocyte Injury in Genetic Podocytopathy

Session Information

Category: Glomerular Diseases

  • 1304 Glomerular Diseases: Podocyte Biology

Authors

  • Dalal, Vidhi, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, United States
  • Kula, Alexander J., Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, United States
  • Verghese, Priya S., Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, United States
  • Hayashida, Tomoko, Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, United States
Background

Up to 30% of pediatric patients with steroid-resistant nephrotic syndrome carry a mutation in genes that are critical for maintaining the podocyte structure. While it is still unpractical to mend individual mutation, some patients develop symptoms later in their life, providing a potential therapeutic window. However, a mechanism by which podocyte injury progress in those patients are largely unknown.

Methods

Single cell suspension was prepared from a portion of nephrectomized kidney of a patient with ACTN4 and ITGB4 mutations and subjected to single cell RNA sequencing (scRNAseq). The data was compared to a dataset from healthy adult kidney at Kidney Interactive Transcriptomics (KIT).

Results

A previously healthy 6-year-old girl with no family history of kidney disease presented with worsening edema. Lab results at admission included serum creatinine 1.25 and albumin 1.2, and urinalysis with 2+glucose, 3+protein, and 1+blood. Biopsy showed 70% global glomerulosclerosis with 50-60% interstitial fibrosis with negative immunofluorescence. She did not respond to 4 weeks of high dose prednisone and transitioned to tacrolimus. CTN4 and ITGB4 mutations were found in her nephrotic syndrome genetic panel and tacrolimus was discontinued. Her serum creatinine rose quickly to 5.8 and protein loss was uncontrollable, therefore bilateral nephrectomy was performed 8 months after presentation. The patient received a kidney from her mother 1 month later, and the graft is fully functional to date. scRNAseq revealed 15 clusters and cluster 10 was annotated as podocytes based on expression of the genes specific to podocytes described in KIT. While expression of some of the podocyte-specific genes (NPHS2, PODXY, SRGAP2B, CCN2 CLIC5, ATP10A) were preserved, other genes (FYN, NTNG1, CDC14A, ALS2CL) were not detected in the patient dataset. The diseaed kidney also expressed genes that are not expressed in the healthy kidney. The most highly differentially upregulated genes only in the diseased kidney include MGP, TAGL ,RGS5, TPM2 and ADIRF. Extracellular matrix genes were also significantly increased in diseased podocytes. Switch in classes of PGPR genes was also observed (Q and O in healthy and D, A, K in diseased podocytes).

Conclusion

Genes identified by scRNAseq implicate potential therapeutic targets for children with genetic podocytopathy.

Funding

  • NIDDK Support