Abstract: SA-PO958
Characterization of the Effects of HIV Vpr on Renal Distal Tubules by Single-Nucleus RNA-Sequencing
Session Information
- CKD: Pathobiology - II
November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: CKD (Non-Dialysis)
- 2203 CKD (Non-Dialysis): Mechanisms
Authors
- Latt, Khun Zaw, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
- Yoshida, Teruhiko, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
- Shrivastav, Shashi, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
- Abedini, Amin, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Lee, Hewang, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, United States
- Zhao, Yongmei, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States
- Chung, Joon-Yong, National Cancer Institute, Bethesda, Maryland, United States
- Rosenberg, Avi Z., Johns Hopkins University, Baltimore, Maryland, United States
- Jose, Pedro A., The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, United States
- Winkler, Cheryl Ann, National Cancer Institute, Bethesda, Maryland, United States
- Knepper, Mark A., National Heart, Lung and Blood Institute, Bethesda, Maryland, United States
- Kino, Tomoshige, Sidra Medicine, Doha, Ad Dawhah, Qatar
- Susztak, Katalin, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Kopp, Jeffrey B., National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
Background
HIV retroviral protein R (Vpr) contributes to the pathogenesis of HIV-associated nephropathy (HIVAN). Vpr induces cell cycle arrest and apoptosis, and regulates expression of glucocorticoid- and mineralocorticoid-responsive genes.
Methods
To investigate the effects of Vpr on aldosterone-mediated regulation of Slc12a3 expression and sodium reabsorption in distal nephron segments, we performed single-nucleus RNA sequencing of wild-type and Vpr transgenic mouse kidney cortex after 4 days of low (0.045%) sodium diet.
Results
In Vpr transgenic mouse, Slc12a3 downregulation was observed in late distal convoluted tubule and connecting tubule cluster (DCT2/CNT) but not in early distal convoluted tubules (DCT1). Expression levels of the mineralocorticoid receptor (Nr3c2) and the enzyme 11-b-hydroxysteroid dehydrogenase 2 (Hsd11b2) genes were higher in the DCT2/CNT compared to the DCT1 cluster. The percentage of DCT cells in Vpr mouse was lower (1.8% of total cells) compared to that observed in salt-depleted WT (3.7%) and salt-replete WT (3.6%). Sub-clustering of distal tubular cell clusters identified Pvalb+ DCT1 and Slc8a1+ DCT2 subclusters. The DCT1 cluster showed fewer cells in Vpr mouse (0.95%) compared to salt-depleted WT (2.9%) and salt-replete WT (3.1%). Pathway analysis of differentially expressed genes in DCT1 cluster showed that genes involved in autophagy and protein ubiquitination were upregulated in Vpr mouse compared to WT. There is an open chromatin mark over a 50 kb region spanning the Slc12a3 gene exclusively in DCT cells, suggesting a DCT-specific super-enhancer state. RNAScope imaging revealed fewer Slc12a3+ DCT segments in Vpr mouse cortex compared to WT.
Conclusion
The downregulation of Slc12a3 and the higher expression levels of Nr3c2 and Hsd11b2 in the DCT2/CNT cluster suggest that the aldosterone-mediated upregulation of Slc12a3 in the context of salt depletion was inhibited by Vpr mostly in late distal convoluted tubules. The major effect of Vpr on the DCT was the loss of DCT1 cells, likely due to autophagy. These observations suggest the salt-wasting effect of Vpr in transgenic mice was associated with loss of Slc12a3+ DCT1 segments and not with the lower abundance in individual DCT1 cells.
Funding
- NIDDK Support