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Abstract: FR-PO340

ReninNull Cells Synthesize Osteopontin, a Likely Cause of Concentric Renal Arteriolar Hypertrophy

Session Information

Category: Hypertension and CVD

  • 1403 Hypertension and CVD: Mechanisms

Authors

  • Watanabe, Hirofumi, University of Virginia School of Medicine, Charlottesville, Virginia, United States
  • Sequeira Lopez, Maria Luisa S., University of Virginia School of Medicine, Charlottesville, Virginia, United States
  • Gomez, Roberto Ariel, University of Virginia School of Medicine, Charlottesville, Virginia, United States
Background

Ren1c gene knockout (Ren1KO) mice develop renal failure and a characteristic renal vascular lesion consisting of concentric arteriolar hypertrophy. Recently, we discovered that in Ren1KO mice, the cells programmed for the renin phenotype (Reninnull cells) survive and increase in numbers along the renal arterial tree, maintain the molecular program of the renin phenotype, and integrate in a chaotic, disorderly manner inside the vessel wall, thus contributing to the vascular abnormality. However, how Reninnull cells are involved in vascular hypertrophy remains to be elucidated.

Methods

We performed transcriptome analysis of renin cells. To isolate renin cells, we generated mice that express yellow fluorescent protein (YFP) under the control of 5 Kb of the 5' regulatory region of the Ren1c gene. YFP-positive cells sorted from the kidneys of Ren1KO mice were processed for single-cell RNA sequencing (scRNA-seq) and compared to cells similarly processed from wild type mice kidneys. RNAs differentially expressed were verified by in situ hybridization using digoxigenin-labeled RNA probes. Plasma osteopontin (OPN) level was examined by ELISA.

Results

Differential expression analysis of scRNA-seq showed 364 genes significantly upregulated in Ren1c wild type cells and 1395 genes significantly upregulated in Ren1KO cells. We identified transcripts of 107 genes corresponding to putative secreted proteins whose expression were found to be enhanced in the cells from Ren1KO mice. Using in situ hybridization, the expression of the several identified genes was detected in the hypertrophic arterioles at higher level in Ren1KO mice than control mice. Spp1 gene that encodes OPN is one of the most significantly upregulated genes in Reninnull cells. With ELISA, we found that plasma OPN level was elevated in Ren1KO mice than control mice.

Conclusion

Reninnull cells in the hypertrophic arterioles in Ren1KO mice express secreted protein genes including Spp1 gene. Further study for the function of these genes may elucidate the mechanisms of vascular hypertrophy.

Funding

  • NIDDK Support