HIV viral protein R induces loss of DCT1-type renal tubules.

HIV viral protein R (Vpr) contributes to HIV-associated nephropathy, induces cell cycle arrest, and alters expression of mineralocorticoid-responsive genes. To investigate Vpr modulation of aldosterone-mediated regulation of the expression of Na-Cl cotransporter Slc12a3 and sodium reabsorption in distal nephron segments, we performed single-nucleus RNA sequencing of kidney cortices of wild-type (WT) and Vpr transgenic (Vpr Tg) mice on low sodium diet and a WT mouse on regular chow. In Vpr Tg mouse, Slc12a3 expression was downregulated in connecting tubules (CNT) and late distal convoluted tubules (DCT2) but not in early DCT (DCT1). Mineralocorticoid receptor ( Nr3c2 ) expression was higher in CNT and DCT2 than in DCT1. DCT1 cell percentage in salt-depleted Vpr Tg was lower (1.8%) compared with salt-depleted or salt-replete WT (3.7% and 3.6%, respectively). Sub-clustering confirmed that Pvalb + DCT1 subcluster had fewer cells in Vpr Tg (0.95%) compared with salt-depleted or salt-replete WT (2.9% and 3.1%, respectively). Autophagy and protein ubiquitination genes were upregulated in DCT1 subcluster of Vpr Tg mice. In situ hybridization and immunohistochemistry demonstrated fewer Slc12a3 + Pvalb + DCT1 segments in Vpr Tg mice. Downregulation of Slc12a3 and higher levels of Nr3c2 in the CNT/DCT2 suggested that the aldosterone-mediated upregulation of Slc12a3 with salt depletion was most prominently inhibited by Vpr in the CNT/DCT2. These observations demonstrate that the salt-wasting effect of Vpr in Vpr Tg mice is mediated by loss of Slc12a3 + Pvalb + DCT1 segments. The downregulation of Slc12a3 occurred in more distal segments rather than in DCT1.