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Lara LS, Gonzalez AA, Hennrikus MT, Prieto MC. Hormone-Dependent Regulation of Renin and Effects on Prorenin Receptor Signaling in the Collecting Duct. Curr Hypertens Rev 2022; 18:91-100. [PMID: 35170417 PMCID: PMC10132771 DOI: 10.2174/1573402118666220216105357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 10/22/2021] [Accepted: 12/13/2021] [Indexed: 01/27/2023]
Abstract
The production of renin by the principal cells of the collecting duct has widened our understanding of the regulation of intrarenal angiotensin II (Ang II) generation and blood pressure. In the collecting duct, Ang II increases the synthesis and secretion of renin by mechanisms involving the activation of Ang II type 1 receptor (AT1R) via stimulation of the PKCα, Ca2+, and cAMP/PKA/CREB pathways. Additionally, paracrine mediators, including vasopressin (AVP), prostaglandins, bradykinin (BK), and atrial natriuretic peptide (ANP), regulate renin in principal cells. During Ang II-dependent hypertension, despite plasma renin activity suppression, renin and prorenin receptor (RPR) are upregulated in the collecting duct and promote de novo formation of intratubular Ang II. Furthermore, activation of PRR by its natural agonists, prorenin and renin, may contribute to the stimulation of profibrotic factors independent of Ang II. Thus, the interactions of RAS components with paracrine hormones within the collecting duct enable tubular compartmentalization of the RAS to orchestrate complex mechanisms that increase intrarenal Ang II, Na+ reabsorption, and blood pressure.
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Affiliation(s)
- Lucienne S Lara
- Instituto de Ciencias Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexis A Gonzalez
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Matthew T Hennrikus
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Minolfa C Prieto
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA, USA.,Tulane Renal and Hypertension Center of Excellence, Tulane University School of Medicine, New Orleans, LA, USA
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Anti-inflammatory, antioxidant, antihypertensive, and antiarrhythmic effect of indole-3-carbinol, a phytochemical derived from cruciferous vegetables. Heliyon 2022; 8:e08989. [PMID: 35243102 PMCID: PMC8866897 DOI: 10.1016/j.heliyon.2022.e08989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/29/2021] [Accepted: 02/15/2022] [Indexed: 11/20/2022] Open
Abstract
Background Cardiovascular inflammation and oxidative stress are determining factors in high blood pressure and arrhythmias. Indole-3-carbinol is a cruciferous-derived phytochemical with potential anti-inflammatory and antioxidant effects. However, its implications on the modulation of cardiovascular inflammatory-oxidative markers are unknown. Objectives To establish the effects of indole-3-carbinol on the oxidative-inflammatory-proarrhythmic conditions associated with hypertension. Materials Histological, biochemical, molecular, and functional aspects were evaluated in 1) Culture of mouse BV-2 glial cells subjected to oxidative-inflammatory damage by lipopolysaccharides (100 ng/mL) in the presence or absence of 40 μM indole-3-carbinol (n = 5); 2) Male spontaneously hypertensive rats (SHR) and Wistar Kyoto rats receiving indole-3-carbinol (2000 ppm/day, orally) during the first 8 weeks of life (n = 15); 3) Isolated rat hearts were submitted to 10 min regional ischemia and 10 min reperfusion. Results 1) lipopolysaccharides induced oxidative stress and increased inflammatory markers; indole-3-carbinol reversed both conditions (interleukin 6, tumor necrosis factor α, the activity of nicotinamide adenine dinucleotide phosphate oxidase, nitric oxide, inducible nitric oxide synthase, heat shock protein 70, all p < 0.01 vs lipopolysaccharides). 2) SHR rats showed histological, structural, and functional changes with increasing systolic blood pressure (154 ± 8 mmHg vs. 122 ± 7 mmHg in Wistar Kyoto rats, p < 0.01); Inflammatory-oxidative markers also increased, and nitric oxide and heat shock protein 70 decreased. Conversely, indole-3-carbinol reduced oxidative-inflammatory markers and systolic blood pressure (133 ± 8 mmHg, p < 0.01 vs. SHR). 3) indole-3-carbinol reduced reperfusion arrhythmias from 8/10 in SHR to 0/10 (p = 0.0007 by Fisher's exact test). Conclusions Indole-3-carbinol reduces the inflammatory-oxidative-proarrhythmic process of hypertension. The nitric oxide and heat shock protein 70 are relevant mechanisms of indole-3-carbinol protective actions. Further studies with this pleiotropic phytochemical as a promising cardioprotective are guaranteed. Indole-3-carbinol, a cruciferous-derived compound, has cardioprotective potential. We confirmed its anti-inflammatory and antioxidant effects in vitro and in vivo. Oral administration reduced blood pressure and cardiac remodeling. In isolated hearts from hypertensive rats prevented ischemia-reperfusion arrhythmias. Heat shock protein 70 and NO contribute to indole-3-carbinol protective actions.
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Solano-Iturri JD, Echevarría E, Unda M, Loizaga-Iriarte A, Pérez-Fernández A, Angulo JC, López JI, Larrinaga G. Clinical Implications of (Pro)renin Receptor (PRR) Expression in Renal Tumours. Diagnostics (Basel) 2021; 11:diagnostics11020272. [PMID: 33578778 PMCID: PMC7916453 DOI: 10.3390/diagnostics11020272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 01/01/2023] Open
Abstract
(1) Background: Renal cancer is one of the most frequent malignancies in Western countries, with an unpredictable clinical outcome, partly due to its high heterogeneity and the scarcity of reliable biomarkers of tumour progression. (Pro)renin receptor (PRR) is a novel receptor of the renin–angiotensin system (RAS) that has been associated with the development and progression of some solid tumours by RAS-dependent and -independent mechanisms. (2) Methods: In this study, we analysed the immunohistochemical expression of PRR at the centre and border in a series of 83 clear-cell renal cell (CCRCCs), 19 papillary (PRCC) and 7 chromophobe (ChRCC) renal cell carcinomas, and the benign tumour renal oncocytoma (RO, n = 11). (3) Results: PRR is expressed in all the tumour subtypes, with higher mean staining intensity in ChRCCs and ROs. A high expression of PRR at the tumour centre and at the infiltrative front of CCRCC tissues is significantly associated with high grade, tumour diameter, local invasion and stage, and with high mortality risk by UCLA integrated staging system (UISS) scale. (4) Conclusions: These findings indicate that PRR is associated with the development and progression of renal tumours. Its potential as a novel biomarker for RCC diagnosis/prognosis and as a promising therapeutic target should be taken into account in the future.
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Affiliation(s)
- Jon Danel Solano-Iturri
- Department of Pathology, Donostia University Hospital, 20014 Donostia/San Sebastian, Spain;
- Department of Medical-Surgical Specialities, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
- Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain;
| | - Enrique Echevarría
- Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
| | - Miguel Unda
- Department of Urology, Basurto University Hospital, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain; (M.U.); (A.L.-I.); (A.P.-F.)
| | - Ana Loizaga-Iriarte
- Department of Urology, Basurto University Hospital, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain; (M.U.); (A.L.-I.); (A.P.-F.)
| | - Amparo Pérez-Fernández
- Department of Urology, Basurto University Hospital, University of the Basque Country (UPV/EHU), 48013 Bilbao, Spain; (M.U.); (A.L.-I.); (A.P.-F.)
| | - Javier C. Angulo
- Clinical Department. Faculty of Medical Sciences. European University of Madrid, 28905 Getafe, Spain;
| | - José I. López
- Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain;
- Department of Pathology, Cruces University Hospital, 48903 Barakaldo, Spain
| | - Gorka Larrinaga
- Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain;
- Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain;
- Department of Nursing, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
- Correspondence:
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High blood pressure induced by vitamin D deficiency is associated with renal overexpression and hyperphosphorylation of Na+-K+-2Cl- cotransporter type 2. J Hypertens 2020; 39:880-891. [PMID: 33337598 DOI: 10.1097/hjh.0000000000002745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Clinical and epidemiological studies have suggested a correlation between vitamin D deficiency (VDD) and high blood pressure (BP). This study aimed to test the hypothesis that high BP induced by VDD is associated with altered expression and covalent modification of apical sodium transporters along the nephron. The contributions of the intrarenal renin-angiotensin system (RAS) and oxidative stress were also investigated. METHODS Male Wistar rats were fed a vitamin D-free (n = 26) or standard diet (n = 25) for 30 days. BP was recorded using noninvasive and invasive procedures. The expression levels of total and phosphorylated apical sodium transporters in rat renal cortex and medulla were evaluated by immunoblotting. Intrarenal RAS components were assessed by immunoblotting and ELISA. Renal oxidative stress was analyzed by measuring the concentrations of thiobarbituric acid reactive substances and reduced glutathione. RESULTS Higher BP levels in VDD rats than controls were accompanied by overexpression and hyperphosphorylation of renal cortical and medullary Na+-K+-2Cl- cotransporter type 2, enhanced levels of phosphorylated Na+/H+ exchanger type 3, and reduced expression levels of total and phosphorylated Na+/Cl- cotransporter. Changes in intrarenal RAS induced by VDD vs. controls included the marked elevation of medullary renin expression, higher expression of cortical angiotensinogen, higher urinary angiotensinogen excretion, and higher cortical and medullary angiotensin II content. VDD rats displayed higher thiobarbituric acid reactive substances/glutathione ratios in the renal cortex and medulla than controls. CONCLUSION These results suggest that the molecular mechanisms underlying the effects of VDD on BP may include the upregulation of Na+-K+-2Cl- cotransporter type 2 and activation of intrarenal RAS and oxidative stress.
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Abstract
The (pro)renin receptor ((P)RR) was first identified as a single-transmembrane receptor in human kidneys and initially attracted attention owing to its potential role as a regulator of the tissue renin-angiotensin system (RAS). Subsequent studies found that the (P)RR is widely distributed in organs throughout the body, including the kidneys, heart, brain, eyes, placenta and the immune system, and has multifaceted functions in vivo. The (P)RR has roles in various physiological processes, such as the cell cycle, autophagy, acid-base balance, energy metabolism, embryonic development, T cell homeostasis, water balance, blood pressure regulation, cardiac remodelling and maintenance of podocyte structure. These roles of the (P)RR are mediated by its effects on important biological systems and pathways including the tissue RAS, vacuolar H+-ATPase, Wnt, partitioning defective homologue (Par) and tyrosine phosphorylation. In addition, the (P)RR has been reported to contribute to the pathogenesis of diseases such as fibrosis, hypertension, pre-eclampsia, diabetic microangiopathy, acute kidney injury, cardiovascular disease, cancer and obesity. Current evidence suggests that the (P)RR has key roles in the normal development and maintenance of vital organs and that dysfunction of the (P)RR is associated with diseases that are characterized by a disruption of the homeostasis of physiological functions.
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Satou R, Penrose H, Navar LG. Inflammation as a Regulator of the Renin-Angiotensin System and Blood Pressure. Curr Hypertens Rep 2018; 20:100. [PMID: 30291560 DOI: 10.1007/s11906-018-0900-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE OF REVIEW Mechanisms facilitating progression of hypertension via cross stimulation of the renin-angiotensin system (RAS) and inflammation have been proposed. Accordingly, we review and update evidence for regulation of RAS components by pro-inflammatory factors. RECENT FINDINGS Angiotensin II (Ang II), which is produced by RAS, induces vasoconstriction and consequent blood pressure elevation. In addition to this direct action, chronically elevated Ang II stimulates several pathophysiological mechanisms including generation of oxidative stress, stimulation of the nervous system, alterations in renal hemodynamics, and activation of the immune system. In particular, an activated immune system has been shown to contribute to the development of hypertension. Recent studies have demonstrated that immune cell-derived pro-inflammatory cytokines regulate RAS components, further accelerating systemic and local Ang II formation. Specifically, regulation of angiotensinogen (AGT) production by pro-inflammatory cytokines in the liver and kidney is proposed as a key mechanism underlying the progression of Ang II-dependent hypertension.
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Affiliation(s)
- Ryousuke Satou
- Department of Physiology and Hypertension and Renal Center of Excellence, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA, 70112-2699, USA.
| | - Harrison Penrose
- Department of Physiology and Hypertension and Renal Center of Excellence, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA, 70112-2699, USA
| | - L Gabriel Navar
- Department of Physiology and Hypertension and Renal Center of Excellence, Tulane University School of Medicine, 1430 Tulane Avenue, SL39, New Orleans, LA, 70112-2699, USA
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Intratubular and intracellular renin-angiotensin system in the kidney: a unifying perspective in blood pressure control. Clin Sci (Lond) 2018; 132:1383-1401. [PMID: 29986878 DOI: 10.1042/cs20180121] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/05/2018] [Accepted: 06/13/2018] [Indexed: 12/18/2022]
Abstract
The renin-angiotensin system (RAS) is widely recognized as one of the most important vasoactive hormonal systems in the physiological regulation of blood pressure and the development of hypertension. This recognition is derived from, and supported by, extensive molecular, cellular, genetic, and pharmacological studies on the circulating (tissue-to-tissue), paracrine (cell-to-cell), and intracrine (intracellular, mitochondrial, nuclear) RAS during last several decades. Now, it is widely accepted that circulating and local RAS may act independently or interactively, to regulate sympathetic activity, systemic and renal hemodynamics, body salt and fluid balance, and blood pressure homeostasis. However, there remains continuous debate with respect to the specific sources of intratubular and intracellular RAS in the kidney and other tissues, the relative contributions of the circulating RAS to intratubular and intracellular RAS, and the roles of intratubular compared with intracellular RAS to the normal control of blood pressure or the development of angiotensin II (ANG II)-dependent hypertension. Based on a lecture given at the recent XI International Symposium on Vasoactive Peptides held in Horizonte, Brazil, this article reviews recent studies using mouse models with global, kidney- or proximal tubule-specific overexpression (knockin) or deletion (knockout) of components of the RAS or its receptors. Although much knowledge has been gained from cell- and tissue-specific transgenic or knockout models, a unifying and integrative approach is now required to better understand how the circulating and local intratubular/intracellular RAS act independently, or with other vasoactive systems, to regulate blood pressure, cardiovascular and kidney function.
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8
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Hennrikus M, Gonzalez AA, Prieto MC. The prorenin receptor in the cardiovascular system and beyond. Am J Physiol Heart Circ Physiol 2018; 314:H139-H145. [PMID: 29101170 PMCID: PMC5867650 DOI: 10.1152/ajpheart.00373.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 01/24/2023]
Abstract
Since the prorenin receptor (PRR) was first reported, its physiological role in many cellular processes has been under intense scrutiny. The PRR is currently recognized as a multifunctional receptor with major roles as an accessory protein of the vacuolar-type H+-ATPase and as an intermediary in the Wnt signaling pathway. As a member of the renin-angiotensin system (RAS), the PRR has demonstrated to be of relevance in cardiovascular diseases (CVD) because it can activate prorenin and enhance the enzymatic activity of renin, thus promoting angiotensin II formation. Indeed, there is an association between PRR gene polymorphisms and CVD. Independent of angiotensin II, the activation of the PRR further stimulates intracellular signals linked to fibrosis. Studies using tissues and cells from a variety of organs and systems have supported its roles in multiple functions, although some remain controversial. In the brain, the PRR appears to be involved in the central regulation of blood pressure via activation of RAS- and non-RAS-dependent mechanisms. In the heart, the PRR promotes atrial structural and electrical remodeling. Nonetheless, animals overexpressing the PRR do not exhibit cardiac injury. In the kidney, the PRR is involved in the development of ureteric bud branching, urine concentration, and regulation of blood pressure. There is great interest in the PRR contributions to T cell homeostasis and to the development of visceral and brown fat. In this mini-review, we discuss the evidence for the pathophysiological roles of the PRR with emphasis in CVD.
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Affiliation(s)
- Matthew Hennrikus
- Department of Physiology, Tulane University School of Medicine , New Orleans, Louisiana
| | - Alexis A Gonzalez
- Instituto de Química, Pontificia Universidad Católica de Valparaíso , Valparaíso , Chile
| | - Minolfa C Prieto
- Department of Physiology, Tulane University School of Medicine , New Orleans, Louisiana
- Tulane University Renal and Hypertension Center of Excellence , New Orleans, Louisiana
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Mullins LJ, Conway BR, Menzies RI, Denby L, Mullins JJ. Renal disease pathophysiology and treatment: contributions from the rat. Dis Model Mech 2017; 9:1419-1433. [PMID: 27935823 PMCID: PMC5200898 DOI: 10.1242/dmm.027276] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The rat has classically been the species of choice for pharmacological studies and disease modeling, providing a source of high-quality physiological data on cardiovascular and renal pathophysiology over many decades. Recent developments in genome engineering now allow us to capitalize on the wealth of knowledge acquired over the last century. Here, we review rat models of hypertension, diabetic nephropathy, and acute and chronic kidney disease. These models have made important contributions to our understanding of renal diseases and have revealed key genes, such as Ace and P2rx7, involved in renal pathogenic processes. By targeting these genes of interest, researchers are gaining a better understanding of the etiology of renal pathologies, with the promised potential of slowing disease progression or even reversing the damage caused. Some, but not all, of these target genes have proved to be of clinical relevance. However, it is now possible to generate more sophisticated and appropriate disease models in the rat, which can recapitulate key aspects of human renal pathology. These advances will ultimately be used to identify new treatments and therapeutic targets of much greater clinical relevance. Summary: This Review highlights the key role that the rat continues to play in improving our understanding of the etiologies of renal pathologies, and how these insights have opened up new therapeutic avenues.
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Affiliation(s)
- Linda J Mullins
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Bryan R Conway
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Robert I Menzies
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Laura Denby
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - John J Mullins
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
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Li XC, Zhuo JL. Recent Updates on the Proximal Tubule Renin-Angiotensin System in Angiotensin II-Dependent Hypertension. Curr Hypertens Rep 2017; 18:63. [PMID: 27372447 DOI: 10.1007/s11906-016-0668-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
It is well recognized that the renin-angiotensin system (RAS) exists not only as circulating, paracrine (cell to cell), but also intracrine (intracellular) system. In the kidney, however, it is difficult to dissect the respective contributions of circulating RAS versus intrarenal RAS to the physiological regulation of proximal tubular Na(+) reabsorption and hypertension. Here, we review recent studies to provide an update in this research field with a focus on the proximal tubular RAS in angiotensin II (ANG II)-induced hypertension. Careful analysis of available evidence supports the hypothesis that both local synthesis or formation and AT1 (AT1a) receptor- and/or megalin-mediated uptake of angiotensinogen (AGT), ANG I and ANG II contribute to high levels of ANG II in the proximal tubules of the kidney. Under physiological conditions, nearly all major components of the RAS including AGT, prorenin, renin, ANG I, and ANG II would be filtered by the glomerulus and taken up by the proximal tubules. In ANG II-dependent hypertension, the expression of AGT, prorenin, and (pro)renin receptors, and angiotensin-converting enzyme (ACE) is upregulated rather than downregulated in the kidney. Furthermore, hypertension damages the glomerular filtration barrier, which augments the filtration of circulating AGT, prorenin, renin, ANG I, and ANG II and their uptake in the proximal tubules. Together, increased local ANG II formation and augmented uptake of circulating ANG II in the proximal tubules, via activation of AT1 (AT1a) receptors and Na(+)/H(+) exchanger 3, may provide a powerful feedforward mechanism for promoting Na(+) retention and the development of ANG II-induced hypertension.
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Affiliation(s)
- Xiao C Li
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA
| | - Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, 2500 North State Street, Jackson, MS, 39216-4505, USA.
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Prieto MC, Reverte V, Mamenko M, Kuczeriszka M, Veiras LC, Rosales CB, McLellan M, Gentile O, Jensen VB, Ichihara A, McDonough AA, Pochynyuk OM, Gonzalez AA. Collecting duct prorenin receptor knockout reduces renal function, increases sodium excretion, and mitigates renal responses in ANG II-induced hypertensive mice. Am J Physiol Renal Physiol 2017; 313:F1243-F1253. [PMID: 28814438 DOI: 10.1152/ajprenal.00152.2017] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/31/2017] [Accepted: 08/14/2017] [Indexed: 12/30/2022] Open
Abstract
Augmented intratubular angiotensin (ANG) II is a key determinant of enhanced distal Na+ reabsorption via activation of epithelial Na+ channels (ENaC) and other transporters, which leads to the development of high blood pressure (BP). In ANG II-induced hypertension, there is increased expression of the prorenin receptor (PRR) in the collecting duct (CD), which has been implicated in the stimulation of the sodium transporters and resultant hypertension. The impact of PRR deletion along the nephron on BP regulation and Na+ handling remains controversial. In the present study, we investigate the role of PRR in the regulation of renal function and BP by using a mouse model with specific deletion of PRR in the CD (CDPRR-KO). At basal conditions, CDPRR-KO mice had decreased renal function and lower systolic BP associated with higher fractional Na+ excretion and lower ANG II levels in urine. After 14 days of ANG II infusion (400 ng·kg-1·min-1), the increases in systolic BP and diastolic BP were mitigated in CDPRR-KO mice. CDPRR-KO mice had lower abundance of cleaved αENaC and γENaC, as well as lower ANG II and renin content in urine compared with wild-type mice. In isolated CD from CDPRR-KO mice, patch-clamp studies demonstrated that ANG II-dependent stimulation of ENaC activity was reduced because of fewer active channels and lower open probability. These data indicate that CD PRR contributes to renal function and BP responses during chronic ANG II infusion by enhancing renin activity, increasing ANG II, and activating ENaC in the distal nephron segments.
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Affiliation(s)
- Minolfa C Prieto
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana;
| | - Virginia Reverte
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Mykola Mamenko
- University of Texas Health Science Center at Houston, Houston Texas
| | - Marta Kuczeriszka
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | | | - Carla B Rosales
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Matthew McLellan
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - Oliver Gentile
- Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana
| | - V Behrana Jensen
- Veterinary Medicine and Surgery, UT MD Anderson Cancer Center, Houston, Texas
| | - Atsuhiro Ichihara
- Tokyo Women's Medical University, Department of Medicine II, Tokyo, Japan; and
| | | | - Oleh M Pochynyuk
- University of Texas Health Science Center at Houston, Houston Texas
| | - Alexis A Gonzalez
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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Prostaglandin E 2 Induces Prorenin-Dependent Activation of (Pro)renin Receptor and Upregulation of Cyclooxygenase-2 in Collecting Duct Cells. Am J Med Sci 2017; 354:310-318. [PMID: 28918839 DOI: 10.1016/j.amjms.2017.05.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 05/26/2017] [Accepted: 05/28/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Prostaglandin E2 (PGE2) regulates renin expression in renal juxtaglomerular cells. PGE2 acts through E-prostanoid (EP) receptors in the renal collecting duct (CD) to regulate sodium and water balance. CD cells express EP1 and EP4, which are linked to protein kinase C (PKC) and PKA downstream pathways, respectively. Previous studies showed that the presence of renin in the CD, and that of PKC and PKA pathways, activate its expression. The (pro)renin receptor (PRR) is also expressed in CD cells, and its activation enhances cyclooxygenase-2 (COX-2) through extracellular signal-regulated kinase (ERK). We hypothesized that PGE2 stimulates prorenin and renin synthesis leading to subsequent activation of PRR and upregulation of COX-2. METHODS We used a mouse M-1 CD cell line that expresses EP1, EP3 and EP4 but not EP2. RESULTS PGE2 (10-6M) treatment increased prorenin and renin protein levels at 4 and 8 hours. No differences were found at 12-hour after PGE2 treatment. Phospho-ERK was significantly augmented after 12 hours. COX-2 expression was decreased after 4 hours of PGE2 treatment, but increased after 12 hours. Interestingly, the full-length form of the PRR was upregulated only at 12 hours. PGE2-mediated phospho-ERK and COX-2 upregulation was suppressed by PRR silencing. CONCLUSIONS Our results suggest that PGE2 induces biphasic regulation of COX-2 through renin-dependent PRR activation via EP1 and EP4 receptors. PRR-mediated increases in COX-2 expression may enhance PGE2 synthesis in CD cells serving as a buffer mechanism in conditions of activated renin-angiotensin system.
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Fletcher A, Huang H, Yu L, Pham Q, Yu L, Wang TTY. Reversible Toxic Effects of the Dietary Supplement Indole-3-Carbinol in an Immune Compromised Rodent Model: Intestine as the Main Target. J Diet Suppl 2016; 14:303-322. [PMID: 27580128 DOI: 10.1080/19390211.2016.1215367] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Dietary supplements are widely used in the United States, but the safety issue remains unresolved. Immuno-deficient or immuno-compromised patients, estimated to exceed 10 million in the United States, are known to use dietary supplements. This population potentially may be susceptible to supplements' adverse effects. The cruciferous vegetable-derived indole-3-carbinol (I3C) is known for its possible protective effects against a number of chronic diseases and is commercially available as a dietary supplement. However, the safety of orally consumed I3C in the general population and particularly in immuno-compromised individuals remains unknown. In this study, rodent model of immune-deficient male BALB/c nu/nu athymic mice were given diets supplemented with 0-100 μmoles I3C/g diet for 4 weeks. We found that BALB/c nu/nu mice were not viable after three days on a 100 μmoles I3C/g supplemented diet. Switching to the control diet (without I3C) after first detection of stress resulted in a 75% recovery of mice. Mice fed with 10-50 μmoles I3C/g supplemented diet survived but showed concentration-dependent adverse effects. More importantly, the intestine appeared to be the target of I3C toxicity. Number and width of intestinal villi were significantly altered by I3C, which associated with a dose-dependent reduction in cell proliferation and increase in apoptosis. Other molecular effects observed for I3C include activation of multiple xenobiotic metabolism pathways. This is the first study to report hazardous effects of I3C supplementation that are specific to the gastrointestinal tract in an immuno-compromised model and should serve as a caution in using I3C as dietary supplements.
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Affiliation(s)
- Arnetta Fletcher
- a Department of Nutrition and Food Science , University of Maryland , College Park, MD , USA
| | - Haiqiu Huang
- a Department of Nutrition and Food Science , University of Maryland , College Park, MD , USA.,b Diet, Genomics, and Immunology Laboratory , Beltsville Human Nutrition Research Center , USDA-ARS, Beltsville , MD , USA
| | - Lu Yu
- a Department of Nutrition and Food Science , University of Maryland , College Park, MD , USA
| | - Quynhchi Pham
- b Diet, Genomics, and Immunology Laboratory , Beltsville Human Nutrition Research Center , USDA-ARS, Beltsville , MD , USA
| | - Liangli Yu
- a Department of Nutrition and Food Science , University of Maryland , College Park, MD , USA
| | - Thomas T Y Wang
- b Diet, Genomics, and Immunology Laboratory , Beltsville Human Nutrition Research Center , USDA-ARS, Beltsville , MD , USA
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Ramkumar N, Kohan DE. Role of the Collecting Duct Renin Angiotensin System in Regulation of Blood Pressure and Renal Function. Curr Hypertens Rep 2016; 18:29. [PMID: 26951246 DOI: 10.1007/s11906-016-0638-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Recent evidence suggests that the renal tubular renin angiotensin system regulates urinary Na(+) and water excretion and blood pressure. Three key components of the tubular renin angiotensin system, namely renin, prorenin receptor, and angiotensin-II type 1 receptor, are localized to the collecting duct. This system may modulate collecting duct Na(+) and water reabsorption via angiotensin-II-dependent and angiotensin-II-independent pathways. Further, the system may be of greatest relevance in hypertensive states and particularly those characterized by high circulating angiotensin-II. In this review, we summarize the current knowledge on the synthesis, regulation, and function of collecting duct-derived renin angiotensin system components and examine recent developments with regard to regulation of blood pressure and renal fluid and Na(+) excretion.
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Affiliation(s)
- Nirupama Ramkumar
- Division of Nephrology, University of Utah Health Sciences Center, 30 N 1900 E SOM 4R312, Salt Lake City, UT, 84132, USA
| | - Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, 30 N 1900 E SOM 4R312, Salt Lake City, UT, 84132, USA. .,Salt Lake Veterans Affairs Medical Center, Salt Lake City, UT, USA.
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15
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Song K, Stuart D, Abraham N, Wang F, Wang S, Yang T, Sigmund CD, Kohan DE, Ramkumar N. Collecting Duct Renin Does Not Mediate DOCA-Salt Hypertension or Renal Injury. PLoS One 2016; 11:e0159872. [PMID: 27467376 PMCID: PMC4965005 DOI: 10.1371/journal.pone.0159872] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/08/2016] [Indexed: 01/09/2023] Open
Abstract
Collecting duct (CD)-derived renin is involved in the hypertensive response to chronic angiotensin-II (Ang-II) administration. However, whether CD renin is involved in Ang-II independent hypertension is currently unknown. To begin to examine this, 12 week old male and female CD-specific renin knock out (KO) mice and their littermate controls were subjected to uni-nephrectomy followed by 2 weeks of deoxycorticosterone acetate (DOCA) infusion combined with a high salt diet. Radiotelemetric blood pressure (BP) was similar between KO and control mice at baseline; BP increased in both groups to a similar degree throughout the 2 weeks of DOCA-salt treatment. Urinary albumin excretion and plasma blood urea nitrogen were comparable between the two groups after DOCA-salt treatment. Fibrosis as assessed by Masson’s Trichrome stain/Sirius Red stain and collagen-1 mRNA expression was similar between control and KO mice. Compared to baseline, DOCA-salt treatment decreased plasma renin concentration (PRC), urinary renin excretion and medullary renin mRNA expression in both floxed and CD renin KO mice with no detectable differences between the two groups. Further, in primary culture of rat inner medullary CD, aldosterone treatment did not change renin activity or total renin content. Taken together, these data suggest that CD derived renin does not play a role in DOCA-salt hypertension.
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Affiliation(s)
- Kai Song
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Department of Nephrology, Second Affiliated Hospital of Soochow University, Soochow City, China
| | - Deborah Stuart
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Nikita Abraham
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Fei Wang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Shuping Wang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Tianxin Yang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
| | - Curt D. Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Donald E. Kohan
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
| | - Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- * E-mail:
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16
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Ramkumar N, Stuart D, Mironova E, Bugay V, Wang S, Abraham N, Ichihara A, Stockand JD, Kohan DE. Renal tubular epithelial cell prorenin receptor regulates blood pressure and sodium transport. Am J Physiol Renal Physiol 2016; 311:F186-94. [PMID: 27053687 DOI: 10.1152/ajprenal.00088.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/31/2016] [Indexed: 12/31/2022] Open
Abstract
The physiological significance of the renal tubular prorenin receptor (PRR) has been difficult to elucidate due to developmental abnormalities associated with global or renal-specific PRR knockout (KO). We recently developed an inducible renal tubule-wide PRR KO using the Pax8/LC1 transgenes and demonstrated that disruption of renal tubular PRR at 1 mo of age caused no renal histological abnormalities. Here, we examined the role of renal tubular PRR in blood pressure (BP) regulation and Na(+) excretion and investigated the signaling mechanisms by which PRR regulates Na(+) balance. No detectable differences in BP were observed between control and PRR KO mice fed normal- or low-Na(+) diets. However, compared with controls, PRR KO mice had elevated plasma renin concentration and lower cumulative Na(+) balance with normal- and low-Na(+) intake. PRR KO mice had an attenuated hypertensive response and reduced Na(+) retention following angiotensin II (ANG II) infusion. Furthermore, PRR KO mice had significantly lower epithelial Na(+) channel (ENaC-α) expression. Treatment with mouse prorenin increased, while PRR antagonism decreased, ENaC activity in isolated split-open collecting ducts (CD). The prorenin effect was prevented by protein kinase A and Akt inhibition, but unaffected by blockade of AT1, ERK1/2, or p38 MAPK pathways. Taken together, these data indicate that renal tubular PRR, likely via direct prorenin/renin stimulation of PKA/Akt-dependent pathways, stimulates CD ENaC activity. Absence of renal tubular PRR promotes Na(+) wasting and reduces the hypertensive response to ANG II.
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Affiliation(s)
- Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah;
| | - Deborah Stuart
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Elena Mironova
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and
| | - Vladislav Bugay
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and
| | - Shuping Wang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Nikita Abraham
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah
| | - Atsuhiro Ichihara
- Department of Medicine II, Endocrinology and Hypertension, Tokyo Women's Medical University, Tokyo, Japan
| | - James D Stockand
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas; and
| | - Donald E Kohan
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; Veterans Affairs Medical Center, Salt Lake City, Utah
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17
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Gonzalez AA, Prieto MC. Renin and the (pro)renin receptor in the renal collecting duct: Role in the pathogenesis of hypertension. Clin Exp Pharmacol Physiol 2015; 42:14-21. [PMID: 25371190 DOI: 10.1111/1440-1681.12319] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/17/2014] [Accepted: 09/30/2014] [Indexed: 12/14/2022]
Abstract
The intrarenal renin-angiotensin system (RAS) plays a critical role in the pathogenesis and progression of hypertension and kidney disease. In angiotensin (Ang) II-dependent hypertension, collecting duct renin synthesis and secretion are stimulated despite suppression of juxtaglomerular (JG) renin. This effect is mediated by the AngII type I receptor (AT1 R), independent of blood pressure. Although the regulation of JG renin has been extensively studied, the mechanisms by which renin is regulated in the collecting duct remain unclear. The augmentation of renin synthesis and activity in the collecting duct may provide a pathway for additional generation of intrarenal and intratubular AngII formation due to the presence of angiotensinogen substrate and angiotensin-converting enzyme in the nephron. The recently described (pro)renin receptor ((P)RR) binds renin or prorenin, enhancing renin activity and fully activating the biologically inactive prorenin peptide. Stimulation of (P)RR also activates intracellular pathways related to fibrosis. Renin and the (P)RR are augmented in renal tissues of AngII-dependent hypertensive rats. However, the functional contribution of the (P)RR to enhanced renin activity in the collecting duct and its contribution to the development of hypertension and kidney disease have not been well elucidated. This review focuses on recent evidence demonstrating the mechanism of renin regulation in the collecting ducts and its interaction with the (P)RR. The data suggest that renin-(P)RR interactions may induce stimulation of intracellular pathways associated with the development of hypertension and kidney disease.
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Affiliation(s)
- Alexis A Gonzalez
- Institute of Chemistry, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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18
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Carey RM. The intrarenal renin-angiotensin system in hypertension. Adv Chronic Kidney Dis 2015; 22:204-10. [PMID: 25908469 DOI: 10.1053/j.ackd.2014.11.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/05/2014] [Accepted: 11/05/2014] [Indexed: 12/22/2022]
Abstract
The renin-angiotensin system (RAS) is a well-studied hormonal cascade controlling fluid and electrolyte balance and blood pressure through systemic actions. The classical RAS includes renin, an enzyme catalyzing the conversion of angiotensinogen to angiotensin (Ang) I, followed by angiotensin-converting enzyme (ACE) cleavage of Ang I to II, and activation of AT1 receptors, which are responsible for all RAS biologic actions. Recent discoveries have transformed the RAS into a far more complex system with several new pathways: the (des-aspartyl(1))-Ang II (Ang III)/AT2 receptor pathway, the ACE-2/Ang (1-7)/Mas receptor pathway, and the prorenin-renin/prorenin receptor/mitogen-activated protein kinase pathway, among others. Although the classical RAS pathway induces Na(+) reabsorption and increases blood pressure, several new pathways constitute a natriuretic/vasodilator arm of the system, opposing detrimental actions of Ang II through Ang II type 1 receptors. Instead of a simple circulating RAS, several independently functioning tissue RASs exist, the most important of which is the intrarenal RAS. Several physiological characteristics of the intrarenal RAS differ from those of the circulating RAS, autoamplifying the activity of the intrarenal RAS and leading to hypertension. This review will update current knowledge on the RAS with particular attention to the intrarenal RAS and its role in the pathophysiology of hypertension.
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19
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Rong R, Ito O, Mori N, Muroya Y, Tamura Y, Mori T, Ito S, Takahashi K, Totsune K, Kohzuki M. Expression of (pro)renin receptor and its upregulation by high salt intake in the rat nephron. Peptides 2015; 63:156-62. [PMID: 25555681 DOI: 10.1016/j.peptides.2014.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 12/22/2014] [Accepted: 12/22/2014] [Indexed: 01/13/2023]
Abstract
A functional receptor for renin and prorenin ((P)RR) was identified as a new component of the renin-angiotensin system. The precise localization of (P)RR in the kidney has not been clarified. The present study was designed to determine the localization of (P)RR in the rat nephron and to investigate the regulation of renal (P)RR expression by high salt (HS) intake. (P)RR mRNA levels in the kidney sections and isolated nephron segments were examined using reverse transcription and polymerase chain reaction (RT-PCR), and (P)RR protein levels were examined by immunoblot and immunohistochemical analyses. Renal (P)RR mRNA and protein levels in rats fed a HS diet for 4 weeks were also compared with those fed a normal salt diet. (P)RR mRNA was expressed in various nephron segments of the cortex and medulla; glomeruli (Glm), proximal tubules (PT), thick ascending limbs (TAL) and collecting ducts (CD). (P)RR protein was highly expressed in the PT, medullary TAL (MTAL) and inner medullary CD (IMCD), and lowly in the preglomerular arterioles (Art) and Glm. HS intake increased (P)RR protein levels in the Glm, PT and tubules of medullary rays. These results indicated that (P)RR is expressed throughout various nephron segments and Art, and that (P)RR protein is expressed predominantly in the PT, MTAL and IMCD. HS intake appears to upregulate the (P)RR expression in the Glm, PT and tubules of medullary rays, suggesting that (P)RR may be involved in the regulation of renal function and HS-induced disorders.
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Affiliation(s)
- Rong Rong
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Osamu Ito
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan.
| | - Nobuyoshi Mori
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Yoshikazu Muroya
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Yuma Tamura
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Takefumi Mori
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology, and Vascular Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
| | - Kazuhiro Takahashi
- Department of Endocrinology and Applied Medical Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8575, Japan
| | - Kazuhito Totsune
- Department of Social Welfare, Tohoku Fukushi University, 1-8-1 Kunimi, Aoba-ku, Sendai, Miyagi 981-8522, Japan
| | - Masahiro Kohzuki
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, 1-1 Seiryo-chyo, Aoba-ku, Sendai 980-8574, Japan
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20
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Kemp BA, Howell NL, Gildea JJ, Keller SR, Padia SH, Carey RM. Response to letter regarding article, "AT2 receptor activation induces natriuresis and lowers blood pressure". Circ Res 2014; 115:e26-7. [PMID: 25301825 DOI: 10.1161/circresaha.114.304975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Brand A Kemp
- Division of Endocrinology and Metabolism Department of Medicine University of Virginia Health System, Charlottesville
| | - Nancy L Howell
- Division of Endocrinology and Metabolism Department of Medicine University of Virginia Health System, Charlottesville
| | - John J Gildea
- Department of Pathology University of Virginia Health System, Charlottesville
| | - Susanna R Keller
- Division of Endocrinology and Metabolism Department of Medicine University of Virginia Health System, Charlottesville
| | - Shetal H Padia
- Division of Endocrinology and Metabolism Department of Medicine University of Virginia Health System, Charlottesville
| | - Robert M Carey
- Division of Endocrinology and Metabolism Department of Medicine University of Virginia Health System, Charlottesville
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21
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Ramkumar N, Stuart D, Rees S, Hoek AV, Sigmund CD, Kohan DE. Collecting duct-specific knockout of renin attenuates angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2014; 307:F931-8. [PMID: 25122048 DOI: 10.1152/ajprenal.00367.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The physiological and pathophysiological significance of collecting duct (CD)-derived renin, particularly as it relates to blood pressure (BP) regulation, is unknown. To address this question, we generated CD-specific renin knockout (KO) mice and examined BP and renal salt and water excretion. Mice containing loxP-flanked exon 1 of the renin gene were crossed with mice transgenic for aquaporin-2-Cre recombinase to achieve CD-specific renin KO. Compared with controls, CD renin KO mice had 70% lower medullary renin mRNA and 90% lower renin mRNA in microdissected cortical CD. Urinary renin levels were significantly lower in KO mice (45% of control levels) while plasma renin concentration was significantly higher in KO mice (63% higher than controls) during normal-Na intake. While no observable differences were noted in BP between the two groups with varying Na intake, infusion of angiotensin II at 400 ng·kg(-1)·min(-1) resulted in an attenuated hypertensive response in the KO mice (mean arterial pressure 111 ± 4 mmHg in KO vs. 128 ± 3 mmHg in controls). Urinary renin excretion and epithelial Na(+) channel (ENaC) remained significantly lower in the KO mice following ANG II infusion compared with controls. Furthermore, membrane-associated ENaC protein levels were significantly lower in KO mice following ANG II infusion. These findings suggest that CD renin modulates BP in ANG II-infused hypertension and these effects are associated with changes in ENaC expression.
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Affiliation(s)
- Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; and
| | - Deborah Stuart
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; and
| | - Sara Rees
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; and
| | - Alfred Van Hoek
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; and
| | - Curt D Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Donald E Kohan
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah; and
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Ferrão FM, Lara LS, Lowe J. Renin-angiotensin system in the kidney: What is new? World J Nephrol 2014; 3:64-76. [PMID: 25332897 PMCID: PMC4202493 DOI: 10.5527/wjn.v3.i3.64] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/07/2014] [Accepted: 07/29/2014] [Indexed: 02/06/2023] Open
Abstract
The renin-angiotensin system (RAS) has been known for more than a century as a cascade that regulates body fluid balance and blood pressure. Angiotensin II(Ang II) has many functions in different tissues; however it is on the kidney that this peptide exerts its main functions. New enzymes, alternative routes for Ang IIformation or even active Ang II-derived peptides have now been described acting on Ang II AT1 or AT2 receptors, or in receptors which have recently been cloned, such as Mas and AT4. Another interesting observation was that old members of the RAS, such as angiotensin converting enzyme (ACE), renin and prorenin, well known by its enzymatic activity, can also activate intracellular signaling pathways, acting as an outside-in signal transduction molecule or on the renin/(Pro)renin receptor. Moreover, the endocrine RAS, now is also known to have paracrine, autocrine and intracrine action on different tissues, expressing necessary components for local Ang II formation. This in situ formation, especially in the kidney, increases Ang II levels to regulate blood pressure and renal functions. These discoveries, such as the ACE2/Ang-(1-7)/Mas axis and its antangonistic effect rather than classical deleterious Ang II effects, improves the development of new drugs for treating hypertension and cardiovascular diseases.
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Mahmud H, Candido WM, van Genne L, Vreeswijk-Baudoin I, Yu H, van de Sluis B, van Deursen J, van Gilst WH, Silljé HHW, de Boer RA. Cardiac function and architecture are maintained in a model of cardiorestricted overexpression of the prorenin-renin receptor. PLoS One 2014; 9:e89929. [PMID: 24587131 PMCID: PMC3934958 DOI: 10.1371/journal.pone.0089929] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/24/2014] [Indexed: 01/25/2023] Open
Abstract
The (pro)renin-renin receptor, (P)RR has been claimed to be a novel element of the renin-angiotensin system (RAS). The function of (P)RR has been widely studied in renal and vascular pathology but the cardio-specific function of (P)RR has not been studied in detail. We therefore generated a transgenic mouse (Tg) with cardio-restricted (P)RR overexpression driven by the alpha-MHC promotor. The mRNA expression of (P)RR was ∼170-fold higher (P<0.001) and protein expression ∼5-fold higher (P<0.001) in hearts of Tg mice as compared to non-transgenic (wild type, Wt) littermates. This level of overexpression was not associated with spontaneous cardiac morphological or functional abnormalities in Tg mice. To assess whether (P)RR could play a role in cardiac hypertrophy, we infused ISO for 28 days, but this caused an equal degree of cardiac hypertrophy and fibrosis in Wt and Tg mice. In addition, ischemia-reperfusion injury was performed in Langendorff perfused isolated mouse hearts. We did not observe differences in parameters of cardiac function or damage between Wt and Tg mouse hearts under these conditions. Finally, we explored whether the hypoxia sensing response would be modulated by (P)RR using HeLa cells with and without (P)RR overexpression. We did not establish any effect of (P)RR on expression of genes associated with the hypoxic response. These results demonstrate that cardio-specific overexpression of (P)RR does not provoke phenotypical differences in the heart, and does not affect the hearts’ response to stress and injury. It is concluded that increased myocardial (P)RR expression is unlikely to have a major role in pathological cardiac remodeling.
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Affiliation(s)
- Hasan Mahmud
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Wellington Mardoqueu Candido
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Linda van Genne
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Inge Vreeswijk-Baudoin
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Hongjuan Yu
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Bart van de Sluis
- University of Groningen, University Medical Center Groningen, Department of Molecular Genetics, Groningen, The Netherlands
| | - Jan van Deursen
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Wiek H. van Gilst
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Herman H. W. Silljé
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
| | - Rudolf A. de Boer
- University of Groningen, University Medical Center Groningen, Department of Cardiology, Groningen, The Netherlands
- * E-mail:
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24
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Zhuo JL, Ferrao FM, Zheng Y, Li XC. New frontiers in the intrarenal Renin-Angiotensin system: a critical review of classical and new paradigms. Front Endocrinol (Lausanne) 2013; 4:166. [PMID: 24273531 PMCID: PMC3822323 DOI: 10.3389/fendo.2013.00166] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/22/2013] [Indexed: 12/23/2022] Open
Abstract
The renin-angiotensin system (RAS) is well-recognized as one of the oldest and most important regulators of arterial blood pressure, cardiovascular, and renal function. New frontiers have recently emerged in the RAS research well beyond its classic paradigm as a potent vasoconstrictor, an aldosterone release stimulator, or a sodium-retaining hormone. First, two new members of the RAS have been uncovered, which include the renin/(Pro)renin receptor (PRR) and angiotensin-converting enzyme 2 (ACE2). Recent studies suggest that prorenin may act on the PRR independent of the classical ACE/ANG II/AT1 receptor axis, whereas ACE2 may degrade ANG II to generate ANG (1-7), which activates the Mas receptor. Second, there is increasing evidence that ANG II may function as an intracellular peptide to activate intracellular and/or nuclear receptors. Third, currently there is a debate on the relative contribution of systemic versus intrarenal RAS to the physiological regulation of blood pressure and the development of hypertension. The objectives of this article are to review and discuss the new insights and perspectives derived from recent studies using novel transgenic mice that either overexpress or are deficient of one key enzyme, ANG peptide, or receptor of the RAS. This information may help us better understand how ANG II acts, both independently or through interactions with other members of the system, to regulate the kidney function and blood pressure in health and disease.
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Affiliation(s)
- Jia L. Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
- Department of Medicine, Division of Nephrology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Fernanda M. Ferrao
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Yun Zheng
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Xiao C. Li
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, USA
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Zhou X, Fukuda N, Matsuda H, Endo M, Wang X, Saito K, Ueno T, Matsumoto T, Matsumoto K, Soma M, Kobayashi N, Nishiyama A. Complement 3 activates the renal renin-angiotensin system by induction of epithelial-to-mesenchymal transition of the nephrotubulus in mice. Am J Physiol Renal Physiol 2013; 305:F957-67. [PMID: 23926185 DOI: 10.1152/ajprenal.00344.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We have demonstrated that mesenchymal cells from spontaneously hypertensive rats genetically express complement 3 (C3). Mature tubular epithelial cells can undergo epithelial-to-mesenchymal transition (EMT) that is linked to the pathogenesis of renal fibrosis and injury. In this study, we investigated the contribution of C3 in EMT and in the renal renin-angiotensin (RA) systems associated with hypertension. C3a induced EMT in mouse TCMK-1 epithelial cells, which displayed increased expression of renin and Krüppel-like factor 5 (KLF5) and nuclear localization of liver X receptor α (LXRα). C3 and renin were strongly stained in the degenerated nephrotubulus and colocalized with LXRα and prorenin receptor in unilateral ureteral obstruction (UUO) kidneys from wild-type mice. In C3-deficient mice, hydronephrus and EMT were suppressed, with no expression of renin and C3. After UUO, systolic blood pressure was increased in wild-type but not C3-deficient mice. In wild-type mice, intrarenal angiotensin II (ANG II) levels were markedly higher in UUO kidneys than normal kidneys and decreased with aliskiren. There were no increases in intrarenal ANG II levels after UUO in C3-deficient mice. Thus C3 induces EMT and dedifferentiation of epithelial cells, which produce renin through induction of LXRα. These data indicate for the first time that C3 may be a primary factor to activate the renal RA systems to induce hypertension.
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Affiliation(s)
- Xueli Zhou
- Div. of Nephrology, Hypertension, and Endocrinology, Dept. of Medicine, Nihon Univ. School of Medicine, Tokyo 173-8610, Japan.
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Ramkumar N, Ying J, Stuart D, Kohan DE. Overexpression of Renin in the collecting duct causes elevated blood pressure. Am J Hypertens 2013; 26:965-72. [PMID: 23702969 DOI: 10.1093/ajh/hpt071] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Renin is synthesized in the collecting duct and is regulated differently than renin in the juxtaglomerular apparatus. However, the physiological relevance of collecting duct renin remains unknown, particularly with regard to its ability to regulate blood pressure. METHODS We used gene targeting to generate mice with overexpression of renin in the collecting duct. A conditional mutant mouse line was created with the mouse renin transcript distal to a "transcriptional stop sequence" such that gene expression only occurred when the stop sequence was excised. These mice were bred with mice transgenic for the aquaporin-2 promoter driving Cre recombinase in order to achieve collecting duct-specific overexpression of renin. RESULTS RNA analysis confirmed kidney-specific recombination, and medullary renin mRNA levels were increased 5-fold in collecting duct renin mice. Blood pressure was recorded by telemetry and plasma and urine was collected in 24-hour metabolic cages on normal, high-, and low-Na+ diets. Although no significant differences in 24-hour urinary Na+ excretion between targeted and control mice were detected, renin overexpresser mice had elevated blood pressure compared with controls on a high-Na+ diet. Urinary renin excretion was 2-fold higher in targeted mice as compared with controls on normal and low-Na+ diets. Plasma renin concentration was significantly suppressed in targeted mice as compared with controls on normal and high-Na+ diets. CONCLUSION Taken together, these results suggest that collecting duct-derived renin has the potential to modulate blood pressure independent of the systemic renin-angiotensin system.
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Affiliation(s)
- Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, UT. USA.
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Ramkumar N, Kohan DE. Role of collecting duct renin in blood pressure regulation. Am J Physiol Regul Integr Comp Physiol 2013; 305:R92-4. [PMID: 23637136 DOI: 10.1152/ajpregu.00191.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Numerous studies indicate that renin is synthesized and secreted by the collecting duct (CD). CD-derived renin may act directly on intercalated and/or principal cells through direct interaction with prorenin receptors and/or through cleavage of proximal tubule-derived angiotensinogen to ultimately produce angiotensin II and activate AT1 receptors. Preliminary studies suggest that the net effect of CD renin would be to increase distal nephron salt reabsorption and increase blood pressure. CD renin production is markedly increased in diabetes and angiotensin II-induced hypertension, suggesting that this system may exert pathophysiological effects. In this brief review, we summarize the current literature on synthesis and regulation of CD renin and consider potential mechanisms by which it regulates blood pressure.
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Affiliation(s)
- Nirupama Ramkumar
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA.
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Prieto MC, Botros FT, Kavanagh K, Navar LG. Prorenin receptor in distal nephron segments of 2-kidney, 1-clip goldblatt hypertensive rats. Ochsner J 2013; 13:26-32. [PMID: 23532382 PMCID: PMC3603183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND The prorenin receptor (PRR) is expressed in the kidneys and has been localized to mesangial cells, renal arterioles, and distal nephron segments. By binding renin or prorenin, this receptor increases renin catalytic activity and activates prorenin. The renin gene is expressed by the principal cells of collecting ducts and is enhanced in angiotensin II (AngII)-dependent hypertension and in both kidneys of 2-kidney, 1-clip (2K1C) Goldblatt hypertensive rats. Colocalization of PRR with prorenin and renin in distal nephron segments may contribute to increased local AngII formation. METHODS We examined the specific cell-type localization of PRR in distal nephron segments and the changes in PRR gene expression in both kidneys of 2K1C hypertensive rats (n=6) and sham-operated rats (n=5). RESULTS After 25 days, systolic blood pressure and plasma renin activity increased to 186 ± 8 mmHg and 12.8 ± 3 ng/AngI/mL/hr, respectively, in 2K1C rats compared to controls (133 ± 9 mmHg and 7.1 ± 1 ng/AngI/mL/hr, respectively). Immunohistochemistry of the PRR on fixed kidney sections showed intense positive staining in the apical aspects of intercalated cells in collecting ducts. PRR immunoreactivity (clipped kidney: 2.3 ± 1 IDU; nonclipped kidney: 1.3 ± 0 IDU; sham: 1.0 ± 0.0 IDU; P<0.05) and messenger RNA levels measured by quantitative real-time polymerase chain reaction (clipped kidney: 1.3 ± 0.1 au; nonclipped kidney: 0.9 ± 0.3 au; sham: 1 ± 0.0 au; P<0.05] were increased in collecting duct cells of clipped kidneys of 2K1C rats compared to nonclipped and sham kidneys. CONCLUSION The enhanced renin gene expression in the collecting ducts of hypertensive rats suggests that the renin secreted by principal cells is then anchored by the PRR on the intercalated cells, thus contributing to increased angiotensin peptide generation in distal nephron segments.
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Affiliation(s)
- Minolfa C. Prieto
- Department of Physiology and Tulane Renal Hypertension Center, Tulane University School of Medicine, New Orleans, LA
| | - Fady T. Botros
- Department of Physiology and Tulane Renal Hypertension Center, Tulane University School of Medicine, New Orleans, LA
| | - Kimberly Kavanagh
- Department of Physiology and Tulane Renal Hypertension Center, Tulane University School of Medicine, New Orleans, LA
| | - L. Gabriel Navar
- Department of Physiology and Tulane Renal Hypertension Center, Tulane University School of Medicine, New Orleans, LA
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Mahmud H, Silljé HHW, Cannon MV, van Gilst WH, de Boer RA. Regulation of the (pro)renin-renin receptor in cardiac remodelling. J Cell Mol Med 2012; 16:722-9. [PMID: 21722305 PMCID: PMC3822843 DOI: 10.1111/j.1582-4934.2011.01377.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The (pro)renin-renin receptor [(P)RR] was discovered as an important novel component of the renin-angiotensin system (RAS). The functional significance of (P)RR is widely studied in renal and vascular pathologies and has sparked interest for a potential role in cardiovascular disease. To investigate the role of (P)RR in cardiac pathophysiology, we aimed to assess (P)RR regulation in adverse cardiac remodelling of the failing heart. In particular, we evaluated the expression of (P)RR in different models of heart failure and across different species. Significantly increased levels of (P)RR mRNA were found in post-myocardial infarcted (MI) hearts of rats (1.6-fold, P < 0.05) and mice (5-fold, P < 0.01), as well as in transgenic rats with overexpression of the mouse renin gene (Ren2) (2.2-fold, P < 0.01). Moreover, we observed a strong increase of (P)RR expression in hearts of dilated cardiomyopathy (DCM) patients (5.3-fold, P < 0.001). Because none of the tested commercially available antibodies appeared to detect endogenous (P)RR, a (P)RR-specific polyclonal antibody was generated to study (P)RR protein levels. (P)RR protein levels were significantly increased in the post-MI rat heart (1.4-fold, P < 0.05) as compared to controls. Most interestingly in DCM patients, a significant 8.7-fold (P < 0.05) increase was observed. Thus, protein expression paralleled gene expression. These results demonstrate that (P)RR expression is strongly up-regulated both in rodent models of heart failure and in the failing human heart, hinting to a potential role for (P)RR in cardiac pathophysiology.
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Affiliation(s)
- Hasan Mahmud
- University Medical Center Groningen, Thorax Center, Department of Cardiology, University of Groningen, The Netherlands
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Prieto MC, Gonzalez AA, Navar LG. Evolving concepts on regulation and function of renin in distal nephron. Pflugers Arch 2012; 465:121-32. [PMID: 22990760 DOI: 10.1007/s00424-012-1151-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 08/24/2012] [Accepted: 08/30/2012] [Indexed: 01/13/2023]
Abstract
Sustained stimulation of the intrarenal/intratubular renin-angiotensin system in a setting of elevated arterial pressure elicits renal vasoconstriction, increased sodium reabsorption, proliferation, fibrosis, and eventual renal injury. Activation of luminal AT(1) receptors in proximal and distal nephron segments by local Ang II formation stimulates various transport systems. Augmented angiotensinogen (AGT) production by proximal tubule cells increases AGT secretion contributing to increased proximal Ang II levels and leading to spillover of AGT into the distal nephron segments, as reflected by increased urinary AGT excretion. The increased distal delivery of AGT provides substrate for renin, which is expressed in principal cells of the collecting tubule and collecting ducts, and is also stimulated by AT(1) receptor activation. Renin and prorenin are secreted into the tubular lumen and act on the AGT delivered from the proximal tubule to form more Ang I. The catalytic actions of renin and or prorenin may be enhanced by binding to prorenin receptors on the intercalated cells or soluble prorenin receptor secreted into the tubular fluid. There is also increased luminal angiotensin converting enzyme in collecting ducts facilitating Ang II formation leading to stimulation of sodium reabsorption via sodium channel and sodium/chloride co-transporter. Thus, increased collecting duct renin contributes to Ang II-dependent hypertension by augmenting distal nephron intratubular Ang II formation leading to sustained stimulation of sodium reabsorption and progression of hypertension.
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Affiliation(s)
- Minolfa C Prieto
- Department of Physiology and Hypertension and Renal Center of Excellence, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA
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Ashek A, Menzies RI, Mullins LJ, Bellamy COC, Harmar AJ, Kenyon CJ, Flatman PW, Mullins JJ, Bailey MA. Activation of thiazide-sensitive co-transport by angiotensin II in the cyp1a1-Ren2 hypertensive rat. PLoS One 2012; 7:e36311. [PMID: 22558431 PMCID: PMC3338649 DOI: 10.1371/journal.pone.0036311] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 04/02/2012] [Indexed: 12/02/2022] Open
Abstract
Transgenic rats with inducible expression of the mouse Ren2 gene were used to elucidate mechanisms leading to the development of hypertension and renal injury. Ren2 transgene activation was induced by administration of a naturally occurring aryl hydrocarbon, indole-3-carbinol (100 mg/kg/day by gastric gavage). Blood pressure and renal parameters were recorded in both conscious and anesthetized (butabarbital sodium; 120 mg/kg IP) rats at selected time-points during the development of hypertension. Hypertension was evident by the second day of treatment, being preceded by reduced renal sodium excretion due to activation of the thiazide-sensitive sodium-chloride co-transporter. Renal injury was evident after the first day of transgene induction, being initially limited to the pre-glomerular vasculature. Mircoalbuminuria and tubuloinsterstitial injury developed once hypertension was established. Chronic treatment with either hydrochlorothiazide or an AT1 receptor antagonist normalized sodium reabsorption, significantly blunted hypertension and prevented renal injury. Urinary aldosterone excretion was increased ∼20 fold, but chronic mineralocorticoid receptor antagonism with spironolactone neither restored natriuretic capacity nor prevented hypertension. Spironolactone nevertheless ameliorated vascular damage and prevented albuminuria. This study finds activation of sodium-chloride co-transport to be a key mechanism in angiotensin II-dependent hypertension. Furthermore, renal vascular injury in this setting reflects both barotrauma and pressure-independent pathways associated with direct detrimental effects of angiotensin II and aldosterone.
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Affiliation(s)
- Ali Ashek
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Robert I. Menzies
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Linda J. Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | | | - Anthony J. Harmar
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher J. Kenyon
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Peter W. Flatman
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, United Kingdom
| | - John J. Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew A. Bailey
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Zhuo JL. Augmented intratubular renin and prorenin expression in the medullary collecting ducts of the kidney as a novel mechanism of angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2011; 301:F1193-4. [PMID: 21993882 PMCID: PMC3233873 DOI: 10.1152/ajprenal.00555.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Howard CG, Mitchell KD. Renal functional responses to selective intrarenal renin inhibition in Cyp1a1-Ren2 transgenic rats with ANG II-dependent malignant hypertension. Am J Physiol Renal Physiol 2011; 302:F52-9. [PMID: 21993885 DOI: 10.1152/ajprenal.00187.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Angiotensin (ANG) II-dependent hypertension is characterized by increases in intrarenal ANG II levels, derangement in renal hemodynamics, and augmented tubular sodium reabsorptive capability. Increased nephron expression of renin-angiotensin system components, such as angiotensinogen by proximal tubule cells and renin by collecting duct principal cells, has been associated with an augmented ability of the kidney to form ANG II in hypertensive states. However, the contribution of de novo intrarenal ANG II production to the development and maintenance of ANG II-dependent hypertension remains unclear. The present study was performed to determine the effects of selective intrarenal renin inhibition on whole kidney hemodynamics and renal excretory function in Cyp1a1-Ren2 rats with ANG II-dependent malignant hypertension in the absence of the confounding influence of associated reductions in mean arterial pressure (MAP). Male Cyp1a1-Ren2 transgenic rats were induced to develop malignant hypertension, anesthetized, and surgically prepared for intrarenal administration of the direct renin inhibitor aliskiren (0.01 mg/kg). Following acute aliskiren treatment, urine flow and sodium excretion increased (10.5 ± 1.1 to 15.9 ± 1.9 μl/min, P < 0.001; 550 ± 160 to 1,370 ± 320 neq/min, P < 0.001, respectively) and ANG II excretion decreased (120 ± 30 to 63 ± 17 fmol/h, P < 0.05). There were no significant changes in MAP, glomerular filtration rate, estimated renal plasma flow, plasma ANG II levels, or protein excretion. The present findings demonstrate that selective renal renin inhibition elicits diuretic and natriuretic responses in Cyp1a1-Ren2 rats with ANG II-dependent malignant hypertension. Elevated intraluminal ANG II levels likely act to augment tubular reabsorptive function and, thereby, contribute to the elevated blood pressure in Cyp1a1-Ren2 rats with ANG II-dependent malignant hypertension.
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Affiliation(s)
- Catherine G Howard
- Dept. of Physiology, Tulane Univ. Health Sciences Center, 1430 Tulane Ave., SL39, New Orleans, LA 70112, USA
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Liu L, Gonzalez AA, McCormack M, Seth DM, Kobori H, Navar LG, Prieto MC. Increased renin excretion is associated with augmented urinary angiotensin II levels in chronic angiotensin II-infused hypertensive rats. Am J Physiol Renal Physiol 2011; 301:F1195-201. [PMID: 21865264 DOI: 10.1152/ajprenal.00339.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Renin expression in principal cells of collecting ducts (CD) is upregulated in angiotensin II (ANG II)-dependent hypertensive rats; however, it remains unclear whether increased CD-derived renin undergoes tubular secretion. Accordingly, urinary levels of renin (uRen), angiotensinogen (uAGT), and ANG II (uANG II) were measured in chronic ANG II-infused Sprague-Dawley rats (80 ng/min for 14 days, n = 10) and sham-operated rats (n = 10). Systolic blood pressure increased in the ANG II rats by day 5 and continued to increase throughout the study (day 13; ANG II: 175 ± 10 vs. sham: 116 ± 2 mmHg; P < 0.05). ANG II infusion increased renal cortical and medullary ANG II levels (cortical ANG II: 606 ± 72 vs. 247 ± 43 fmol/g; P < 0.05; medullary ANG II: 2,066 ± 116 vs. 646 ± 36 fmol/g; P < 0.05). Although plasma renin activity (PRA) was suppressed in the ANG II-infused rats (0.3 ± 0.2 vs. 5.5 ± 1.8 ng ANG I·ml(-1)·h(-1); P < 0.05), renin content in renal medulla was increased (12,605 ± 1,343 vs. 7,956 ± 765 ng ANG I·h(-1)·mg(-1); P < 0.05). Excretion of uAGT and uANG II increased in the ANG II rats [uAGT: 1,107 ± 106 vs. 60 ± 26 ng/day; P < 0.0001; uANG II: 3,813 ± 431 vs. 2,080 ± 361 fmol/day; P < 0.05]. By day 13, despite suppression of PRA, urinary prorenin content increased in ANG II rats [15.7 ± 3 vs. 2.6 ± 1 × 10(-3) enzyme units excreted (EUE)/day, P < 0.01] as was the excretion rate of renin (8.6 ± 2 × 10(-6) EUE/day) compared with sham (2.8 ± 1 × 10(-6) EUE/day; P < 0.05). Urinary renin and prorenin protein levels examined by Western blot were augmented ∼10-fold in the ANG II-infused rats. Concomitant AT(1) receptor blockade with candesartan prevented the increase. Thus, in ANG II-dependent hypertensive rats with marked PRA suppression, increased urinary levels of renin and prorenin reflect their augmented secretion by CD cells into the luminal fluid. The greater availability of renin and AGT in the urine reflects the capability for intratubular ANG II formation which stimulates sodium reabsorption in distal nephron segments.
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Affiliation(s)
- Liu Liu
- Dept. of Physiology, Tulane University School of Medicine, 1430 Tulane Ave., New Orleans, LA, USA
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Lee HA, Lee DY, Lee HJ, Han HS, Kim I. Enrichment of (pro)renin receptor promoter with activating histone codes in the kidneys of spontaneously hypertensive rats. J Renin Angiotensin Aldosterone Syst 2011; 13:11-8. [PMID: 21803797 DOI: 10.1177/1470320311415738] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The (pro)renin receptor [(P)RR] non-proteolytically, through conformational change, activates prorenin which can convert angiotensinogen to angiotensin I in addition to the classic conversion of angiotensinogen to angiotensin I by circulating renin. Since renal (P)RR is upregulated in hypertension and implicated in the pathogenesis of malignant hypertension, we hypothesized that (pro)renin receptor promoter is enriched with activating histone codes in the kidney of spontaneously hypertensive rats (SHR). METHODS The mRNA and protein expression levels were measured by real-time polymerase chain reaction (PCR) and western blot, respectively. The DNA methylation status of (P)RR promoter region was analyzed by bisulfite sequencing. The histone modifications were determined by chromatin immunoprecipitation followed by real-time PCR. RESULTS The (P)RR mRNA expression in the kidney was about six times greater in SHR than in Wistar-Kyoto (WKY) rats. The (P)RR promoter was little methylated in the kidneys of both WKY and SHR. Acetylated histone H3 (H3Ac) and di-methylated histone H3 at lysine 4 (H3K4me2), activating histone codes, were about 25 and three times higher in SHR than in WKY, respectively. On the other hand, di-methylated histone H3 at lysine 9 (H3K9me2), a suppressive histone code, was 50 times lower in SHR than in WKY. CONCLUSION These results suggest that the (P)RR promoter is enriched with activating histone codes in the kidneys of SHR.
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Affiliation(s)
- Hae-Ahm Lee
- Department of Pharmacology, Kyungpook National University School of Medicine, Daegu, Korea
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Navar LG, Prieto MC, Satou R, Kobori H. Intrarenal angiotensin II and its contribution to the genesis of chronic hypertension. Curr Opin Pharmacol 2011; 11:180-6. [PMID: 21339086 DOI: 10.1016/j.coph.2011.01.009] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 01/27/2011] [Accepted: 01/28/2011] [Indexed: 12/20/2022]
Abstract
The increased activity of intrarenal renin-angiotensin system (RAS) in a setting of elevated arterial pressure elicits renal vasoconstriction, increased sodium reabsorption, proliferation, fibrosis and renal injury. Increases in intrarenal and interstitial angiotensin (Ang) II levels are due to increased AT(1) receptor mediated Ang II uptake and stimulation of renal angiotensinogen (AGT) mRNA and protein expression. Augmented proximal tubule AGT production increases tubular AGT secretion and spillover of AGT into the distal nephron and urine. Increased renin formation by principal cells of the collecting ducts forms Ang I from AGT thus increasing Ang II. The catalytic actions of renin and prorenin are enhanced by prorenin receptors (PRRs) on the intercalated cells. The resultant increased intrarenal Ang II levels contribute to the genesis of chronic hypertension.
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Affiliation(s)
- L Gabriel Navar
- Department of Physiology and the Hypertension and Renal Center of Excellence, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, USA.
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Gonzalez AA, Lara LS, Luffman C, Seth DM, Prieto MC. Soluble form of the (pro)renin receptor is augmented in the collecting duct and urine of chronic angiotensin II-dependent hypertensive rats. Hypertension 2011; 57:859-64. [PMID: 21321306 DOI: 10.1161/hypertensionaha.110.167957] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Renin synthesis and secretion by principal cells of the collecting duct are enhanced in angiotensin (Ang) II-dependent hypertension. The presence of renin/(pro)renin and its receptor, the (pro)renin receptor ([P]RR), in the collecting duct may provide a pathway for Ang I generation with further conversion to Ang II. To assess whether (P)RR activation occurs during Ang II-dependent hypertension, we examined renal (P)RR levels and soluble (P)RR excretion in the urine of chronic Ang II-infused rats (80 ng/min; for 2 weeks; n=10) and sham-operated rats (n=10). Systolic blood pressure and Ang II levels in the plasma and kidney were increased whereas plasma renin activity was suppressed in Ang II-infused rats. Renal (P)RR transcripts were upregulated in the cortex and medulla of Ang II-infused rats. (P)RR immunoreactivity in collecting duct cells and the protein levels of the full-length form (37-kDa band) were significantly decreased in the medulla of Ang II-infused rats. The soluble (P)RR (28-kDa band) was detected in the renal medulla and urine samples of Ang II-infused rats, which also showed increases in urinary renin content. To determine whether the soluble (P)RR could stimulate Ang I formation, urine samples were incubated with recombinant human (pro)renin. Urine samples of Ang II-infused rats exhibited increased Ang I formation compared with sham-operated rats. Thus, in chronic Ang II-infused rats, the catalytic activity of the augmented renin produced in the collecting duct may be enhanced by the intraluminal soluble (P)RR and cell-surface located (P)RR, thus contributing to enhanced intratubular Ang II formation.
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Affiliation(s)
- Alexis A Gonzalez
- Department of Physiology, Tulane University, School of Medicine, 1430 Tulane Ave, SL39, New Orleans, LA 70112, USA
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