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Background: Renal T cells contribute importantly to hypertension, but the underlying mechanism is incompletely understood. We reported that CD8Ts directly stimulate distal convoluted tubule cells (DCTs) to increase NCC (sodium chloride co-transporter) expression and salt reabsorption. However, the mechanistic basis of this pathogenic pathway that promotes hypertension remains to be elucidated., Methods: We used mouse models of DOCA+salt (DOCA) treatment and adoptive transfer of CD8 + T cells (CD8T) from hypertensive animals to normotensive animals in in vivo studies. Co-culture of mouse DCTs and CD8Ts was used as in vitro model to test the effect of CD8T activation in promoting NCC-mediated sodium retention and to identify critical molecular players contributing to the CD8T-DCT interaction. Interferon (IFNγ)-KO mice and mice receiving renal tubule-specific knockdown of PDL1 were used to verify in vitro findings. Blood pressure was continuously monitored via radio-biotelemetry, and kidney samples were saved at experimental end points for analysis., Results: We identified critical molecular players and demonstrated their roles in augmenting the CD8T-DCT interaction leading to salt-sensitive hypertension. We found that activated CD8Ts exhibit enhanced interaction with DCTs via IFN-γ-induced upregulation of MHC-I and PDL1 in DCTs, thereby stimulating higher expression of NCC in DCTs to cause excessive salt retention and progressive elevation of blood pressure. Eliminating IFN-γ or renal tubule-specific knockdown of PDL1 prevented T cell homing into the kidney, thereby attenuating hypertension in 2 different mouse models., Conclusions: Our results identified the role of activated CD8Ts in contributing to increased sodium retention in DCTS through the IFNγ-PDL1 pathway. These findings provide a new mechanism for T cell involvement in the pathogenesis of hypertension and reveal novel therapeutic targets.

The incidence of kidney cancer has been increasing steadily and, until recently, there was a substantial lack of effective therapies for a cancer that is now among the 10 most common cancers in men and women. During the past 10 years, novel therapies have been developed including antiangiogenic drugs targeting vascular endothelial growth factor and its receptors, immune checkpoint inhibitors, and mammalian target of rapamycin inhibitors that have resulted in a significant improvement in clinical outcomes in a traditionally difficult-to-treat cancer. These new drugs, however, also have important side effects and toxicities that often have an impact on the treatment of these patients. The use of anti-angiogenic drugs often results in the development of hypertension and, less frequently, varying degrees of proteinuria including nephrotic range proteinuria. A variety of agents are used for the treatment of hypertension and proteinuria including blockers of the renin angiotensin system and calcium channel blockers, but there are no randomized clinical trials comparing different therapeutic agents in these patients. Immune checkpoint inhibitors have become one of the cornerstones of therapy in kidney cancer, but their use is linked to a variety of side effects that affect almost every organ and resemble autoimmune diseases. In the kidney, these drugs can induce acute interstitial nephritis in close to 5% of patients with varying degrees of severity that in some cases require discontinuation of treatment and systemic treatment with corticosteroids. Although mammalian target of rapamycin inhibitors now also are part of the therapeutic armamentarium available for these patients, all clinical trials have been performed in patients with normal renal function and therefore their effects in patients with abnormal renal function are not known., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Studies using Dahl salt-sensitive (SS) rats identified specific quantitative trait loci that predispose animals to hypertension-associated albuminuria and kidney injury. We explored the hypothesis that kidney-specific expression of the transcription factor Ets-1 , located within one of these loci on chromosome 8, mediates glomerular injury in SS hypertension. During the first week on a high-salt diet, SS rats and SS rats with only one functioning Ets-1 gene (ES rats) demonstrated similar increases in BP. However, serum creatinine concentration, albuminuria, and glomerular expression of ETS-1 and two ETS-1 targets, MCP-1 and MMP2, did not increase as substantially in ES rats as in SS rats. Mean BP subsequently increased further in SS rats and remained higher than that of ES rats for the rest of the study. After 4 weeks of high-salt intake, ES rats still showed a lower mean serum creatinine concentration and less albuminuria, as well as less histologic evidence of glomerular injury and kidney fibrosis, than SS rats did. To investigate the specific contribution of renal Ets-1 , we transplanted kidneys from ES or SS rats into salt-resistant SS-Chr 13 BN/ McwiCrl (SS-13BN) rats. Within 10 days on a high-salt diet, BP increased similarly in ES and SS allograft recipients, becoming significantly higher than the BP of control isograft recipients. However, mean serum creatinine concentration and albuminuria remained lower in ES allograft recipients than in SS allograft recipients at 2 weeks, and ES allografts showed less glomerular injury and interstitial fibrosis. In conclusion, reduced renal expression of ETS-1 prevented hypertension-associated kidney injury in SS rats., (Copyright © 2017 by the American Society of Nephrology.)

Transcription factor E26 transformation-specific sequence-1 (ETS-1) is a transcription factor that regulates the expression of a variety of genes, including growth factors, chemokines, and adhesion molecules. We recently demonstrated that angiotensin II increases the glomerular expression of ETS-1 and that blockade of ETS-1 ameliorates the profibrotic and proinflammatory effects of angiotensin II. The Dahl salt-sensitive rat is a paradigm of salt-sensitive hypertension associated with local activation of the renin-angiotensin system. In these studies, we determined whether: (1) salt-sensitive hypertension is associated with renal expression of ETS-1 and (2) ETS-1 participates in the development of end-organ injury in salt-sensitive hypertension. Dahl salt-sensitive rats were fed a normal-salt diet (0.5% NaCl diet) or a high-salt diet (4% NaCl) for 4 weeks. Separate groups on high-salt diet received an ETS-1 dominant-negative peptide (10 mg/kg/d), an inactive ETS-1 mutant peptide (10 mg/kg/d), the angiotensin II type 1 receptor blocker candesartan (10 mg/kg/d), or the combination high-salt diet/dominant-negative peptide/angiotensin II type 1 receptor blocker for 4 weeks. High-salt diet rats had a significant increase in the glomerular expression of the phosphorylated ETS-1 that was prevented by angiotensin II type 1 receptor blocker. ETS-1 blockade reduced proteinuria, glomerular injury score, fibronectin expression, urinary transforming growth factor-β excretion, and macrophage infiltration. Angiotensin II type 1 receptor blocker reduced proteinuria, glomerular injury score, and macrophage infiltration, whereas concomitant ETS-1 blockade and angiotensin II type 1 receptor blocker had additive effects and reduced interstitial fibrosis. Our studies demonstrated that salt-sensitive hypertension results in increased glomerular expression of phosphorylated ETS-1 and suggested that ETS-1 plays an important role in the pathogenesis of end-organ injury in salt-sensitive hypertension., (© 2015 American Heart Association, Inc.)

VEGF (vascular endothelial growth factor) receptor tyrosine kinase inhibitors have become first-line therapy for metastatic renal cell carcinoma. Their use commonly leads to hypertension, but their effects on long-term renal function are not known. In addition, it has been suggested that the development of hypertension is linked to treatment efficacy. The objective of this study was to determine the effects of these drugs on long-term renal function, especially in those with renal dysfunction at baseline, and to examine the role of hypertension on these effects. Serum creatinine measurements were used to calculate the estimated glomerular filtration rate for 130 renal cell carcinoma patients who were treated with this class of tyrosine kinase inhibitors. New or worsening hypertension was defined by documented start or addition of antihypertensive medications. Overall, the use of tyrosine kinase inhibitors in patients with estimated glomerular filtration <60 or ≥60 mL/min per 1.73 m2 was not associated with a decline in long-term renal function. During follow-up, 41 patients developed new or worsening hypertension within 30 days from first drug administration, and this was not linked to further reductions in glomerular filtration. These patients seemed to survive longer than those who did not develop hypertension within 30 days, although this was not statistically significant (P=0.07). Our findings suggest that the use of VEGF tyrosine kinase inhibitors does not adversely affect long-term renal function even in the setting of new-onset hypertension or reduced renal function at baseline. [ABSTRACT FROM AUTHOR]

Transcription factor E26 transformation-specific sequence-1 (ETS-1) is a transcription factor that regulates the expression of a variety of genes, including growth factors, chemokines, and adhesion molecules. We recently demonstrated that angiotensin II increases the glomerular expression of ETS-1 and that blockade of ETS-1 ameliorates the profibrotic and proinflammatory effects of angiotensin II. The Dahl salt-sensitive rat is a paradigm of salt-sensitive hypertension associated with local activation of the renin-angiotensin system. In these studies, we determined whether: (1) salt-sensitive hypertension is associated with renal expression of ETS-1 and (2) ETS-1 participates in the development of end-organ injury in salt-sensitive hypertension. Dahl salt-sensitive rats were fed a normal-salt diet (0.5% NaCl diet) or a high-salt diet (4% NaCl) for 4 weeks. Separate groups on high-salt diet received an ETS-1 dominant-negative peptide (10 mg/kg/d), an inactive ETS-1 mutant peptide (10 mg/kg/d), the angiotensin II type 1 receptor blocker candesartan (10 mg/kg/d), or the combination high-salt diet/dominant-negative peptide/angiotensin II type 1 receptor blocker for 4 weeks. High-salt diet rats had a significant increase in the glomerular expression of the phosphorylated ETS-1 that was prevented by angiotensin II type 1 receptor blocker. ETS-1 blockade reduced proteinuria, glomerular injury score, fibronectin expression, urinary transforming growth factor-β excretion, and macrophage infiltration. Angiotensin II type 1 receptor blocker reduced proteinuria, glomerular injury score, and macrophage infiltration, whereas concomitant ETS-1 blockade and angiotensin II type 1 receptor blocker had additive effects and reduced interstitial fibrosis. Our studies demonstrated that salt-sensitive hypertension results in increased glomerular expression of phosphorylated ETS-1 and suggested that ETS-1 plays an important role in the pathogenesis of end-organ injury in saltsensitive hypertension. [ABSTRACT FROM AUTHOR]