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Gambaryan S, Mohagaonkar S, Nikolaev VO. Regulation of the renin-angiotensin-aldosterone system by cyclic nucleotides and phosphodiesterases. Front Endocrinol (Lausanne) 2023; 14:1239492. [PMID: 37674612 PMCID: PMC10478253 DOI: 10.3389/fendo.2023.1239492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023] Open
Abstract
The renin-angiotensin-aldosterone system (RAAS) is one of the key players in the regulation of blood volume and blood pressure. Dysfunction of this system is connected with cardiovascular and renal diseases. Regulation of RAAS is under the control of multiple intracellular mechanisms. Cyclic nucleotides and phosphodiesterases are the major regulators of this system since they control expression and activity of renin and aldosterone. In this review, we summarize known mechanisms by which cyclic nucleotides and phosphodiesterases regulate renin gene expression, secretion of renin granules from juxtaglomerular cells and aldosterone production from zona glomerulosa cells of adrenal gland. We also discuss several open questions which deserve future attention.
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Affiliation(s)
- Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Sanika Mohagaonkar
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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2
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Rahimibashar F, Sedighi L, Shahriary A, Reiner Z, Pourhoseingholi MA, Mirmomeni G, Jouzdani AF, Vahedian-Azimi A, Jamialahmadi T, Sahebkar A. Is there any association between plasma lipid profile and severity of COVID-19? Clin Nutr ESPEN 2022; 49:191-196. [PMID: 35623812 PMCID: PMC9047402 DOI: 10.1016/j.clnesp.2022.04.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND COVID-19 is an infectious disease which caused a pandemic with many diseases and fatalities. This new variant of coronavirus called SARS-CoV-2 and is primarily characterized by respiratory symptoms. There are some data indicating that LDL-cholesterol (LDL-C) as well as HDL-cholesterol (HDL-C) levels are inversely correlated to disease severity and could act as a predictor for disease progression and unfavorable prognosis. However, the results of some other studies do not confirm this. This current study aimed to provide an answer to this question. METHODS This prospective, single-center study analyzed 367 confirmed COVID-19 patients to find whether there are any differences in plasma lipoproteins between survivors and non-survivors patients or between the patients with a "duration of ≤10 days intensive unit care (ICU) stay" and patients with a "duration of >10 days ICU stay". RESULTS No association between any lipid/lipoprotein parameter and the severity of COVID-19 could be found but survivors and non-survivors did differ concerning total cholesterol and LDL-C levels. CONCLUSION Multivariate cox regression analysis could not prove any association between lipids/lipoproteins and severe events in COVID-19 patients. Significantly less non-survivors with COVID-19 were taking atorvastatin than survivors which is consistent with the majority of previous findings.
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Affiliation(s)
- Farshid Rahimibashar
- Department of Anesthesiology and Critical Care, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Ladan Sedighi
- Department of Medical and Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alireza Shahriary
- Chemical Injuries Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Zeljko Reiner
- Department of Internal Diseases, University Hospital Center Zagreb School of Medicine, Zagreb University, Zagreb, Croatia
| | - Mohamad Amin Pourhoseingholi
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Golshan Mirmomeni
- Hearing Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ali Fathi Jouzdani
- Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Amir Vahedian-Azimi
- Trauma Research Center, Nursing Faculty, Baqiyatallah University of Medical Sciences, Tehran, Iran,Corresponding author
| | - Tannaz Jamialahmadi
- Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran,Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran,Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran,Corresponding author. Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Hu L, Chen Y, Zhou X, Hoek M, Cox J, Lin K, Liu Y, Blumenschein W, Grein J, Swaminath G. Effects of soluble guanylate cyclase stimulator on renal function in ZSF-1 model of diabetic nephropathy. PLoS One 2022; 17:e0261000. [PMID: 35085251 PMCID: PMC8794189 DOI: 10.1371/journal.pone.0261000] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 11/23/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Diabetic nephropathy is associated with endothelial dysfunction and oxidative stress, in which the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway is impaired. We hypothesize that sGC stimulator Compound 1 can enhance NO signaling, reduce proteinuria in a diabetic nephropathy preclinical model with diminished NO bioavailability and increased oxidized sGC. Therefore, we evaluated the effect of sGC stimulator Compound 1 on the renal effect in obese ZSF1 (ZSF1 OB) rats. MATERIALS AND METHODS The sGC stimulator Compound 1, the standard of care agent Enalapril, and a combination of Compound 1 and Enalapril were administered chronically to obese ZSF1 rats for 6 months. Mean arterial pressure, heart rate, creatinine clearance for glomerular filtration rate (eGFR), urinary protein excretion to creatinine ratio (UPCR), and urinary albumin excretion ratio (UACR) were determined during the study. The histopathology of glomerular and interstitial lesions was assessed at the completion of the study. RESULTS While both Compound 1 and Enalapril significantly reduced blood pressure, the combination of Compound 1 and Enalapril normalized blood pressure levels. Compound 1 improved eGFR and reduced UPCR and UACR. A combination of Enalapril and Compound 1 resulted in a marked reduction in UPCR and UACR and improved GFR. CONCLUSION The sGC stimulator Compound 1 as a monotherapy slowed renal disease progression, and a combination of the sGC stimulator with Enalapril provided greater renal protection in a rodent model of diabetic nephropathy.
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Affiliation(s)
- Lufei Hu
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Yinhong Chen
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Xiaoyan Zhou
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Maarten Hoek
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Biology Department, Maze Therapeutics, San Francisco, CA, United States of America
| | - Jason Cox
- Chemistry, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Discovery Chemistry, Kinnate Biopharma, San Diego, CA, United States of America
| | - Ken Lin
- Pharmacokinetics, Pharmacodynamics & Drug Metabolism, Merck & Co., Inc., Kenilworth, NJ, United States of America
- Drug Metabolism and Pharmacokinetics, BridgeBio, Palo Alto, CA, United States of America
| | - Yang Liu
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
| | - Wendy Blumenschein
- Department of Molecular Discovery Profiling and Expression, Merck & Co. Inc., Kenilworth, NJ, United States of America
| | - Jeff Grein
- Department of Molecular Discovery Profiling and Expression, Merck & Co. Inc., Kenilworth, NJ, United States of America
| | - Gayathri Swaminath
- Department of Cardiometabolic Diseases, Merck & Co., Inc., Kenilworth, NJ, United States of America
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Effects of Statins on Renin-Angiotensin System. J Cardiovasc Dev Dis 2021; 8:jcdd8070080. [PMID: 34357323 PMCID: PMC8305238 DOI: 10.3390/jcdd8070080] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 12/16/2022] Open
Abstract
Statins, a class of drugs for lowering serum LDL-cholesterol, have attracted attention because of their wide range of pleiotropic effects. An important but often neglected effect of statins is their role in the renin–angiotensin system (RAS) pathway. This pathway plays an integral role in the progression of several diseases including hypertension, heart failure, and renal disease. In this paper, the role of statins in the blockade of different components of this pathway and the underlying mechanisms are reviewed and new therapeutic possibilities of statins are suggested.
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Kannabiran SA, Gosejacob D, Niemann B, Nikolaev VO, Pfeifer A. Real-time monitoring of cAMP in brown adipocytes reveals differential compartmentation of β 1 and β 3-adrenoceptor signalling. Mol Metab 2020; 37:100986. [PMID: 32247064 PMCID: PMC7191645 DOI: 10.1016/j.molmet.2020.100986] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 11/17/2022] Open
Abstract
Objective 3′,5′-Cyclic adenosine monophosphate (cAMP) is a central second messenger governing brown adipocyte differentiation and function. β-adrenergic receptors (β-ARs) stimulate adenylate cyclases which produce cAMP. Moreover, cyclic nucleotide levels are tightly controlled by phosphodiesterases (PDEs), which can generate subcellular microdomains of cAMP. Since the spatio-temporal organisation of the cAMP signalling pathway in adipocytes is still unclear, we sought to monitor real-time cAMP dynamics by live cell imaging in pre-mature and mature brown adipocytes. Methods We measured the real-time dynamics of cAMP in murine pre-mature and mature brown adipocytes during stimulation of individual β-AR subtypes, as well as its regulation by PDEs using a Förster Resonance Energy Transfer based biosensor and pharmacological tools. We also correlated these data with β-AR stimulated lipolysis and analysed the expression of β-ARs and PDEs in brown adipocytes using qPCR and immunoblotting. Furthermore, subcellular distribution of PDEs was studied using cell fractionation and immunoblots. Results Using pre-mature and mature brown adipocytes isolated from transgenic mice expressing a highly sensitive cytosolic biosensor Epac1-camps, we established real-time measurements of cAMP responses. PDE4 turned out to be the major PDE regulating cytosolic cAMP in brown preadipocytes. Upon maturation, PDE3 gets upregulated and contributes with PDE4 to control β1-AR-induced cAMP. Unexpectedly, β3-AR initiated cAMP is resistant to increased PDE3 protein levels and simultaneously, the control of this microdomain by PDE4 is reduced upon brown adipocyte maturation. Therefore we postulate the existence of distinct cAMP pools in brown adipocytes. One cAMP pool is formed by β1-AR associated with PDE3 and PDE4, while another pool is centred around β3-AR and is much less controlled by these PDEs. Functionally, lower control of β3-AR initiated cAMP by PDE3 and PDE4 facilitates brown adipocyte lipolysis, while lipolysis activated by β1-AR and is under tight control of PDE3 and PDE4. Conclusions We have established a real-time live cell imaging approach to analyse brown adipocyte cAMP dynamics in real-time using a cAMP biosensor. We showed that during the differentiation from pre-mature to mature murine brown adipocytes, there was a change in PDE-dependent compartmentation of β1-and β3-AR-initiated cAMP responses by PDE3 and PDE4 regulating lipolysis. Establishment of real-time cAMP analysis using a FRET biosensor in brown adipocytes. Real-time dynamics of cAMP generation from different β-adrenoceptor subtypes in pre- and mature brown adipocytes. Expression analysis of PDE families in pre- and mature brown adipocytes. Differences in PDE3- and PDE4-dependent regulation of β1- and β3-adrenoceptor initiated cAMP signalling in brown adipocytes. Differential compartmentation of β1- and β3-adrenoceptor signalling in brown adipocytes.
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Affiliation(s)
- Sukanya Arcot Kannabiran
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Research Training Group 1873, University of Bonn, 53127, Bonn, Germany
| | - Dominic Gosejacob
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany.
| | - Birte Niemann
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Bonn International Graduate School of Drug Sciences (BIGS DrugS), Germany
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany.
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, 53127, Bonn, Germany; Research Training Group 1873, University of Bonn, 53127, Bonn, Germany; Bonn International Graduate School of Drug Sciences (BIGS DrugS), Germany.
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Leipziger J, Praetorius H. Renal Autocrine and Paracrine Signaling: A Story of Self-protection. Physiol Rev 2020; 100:1229-1289. [PMID: 31999508 DOI: 10.1152/physrev.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.
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Affiliation(s)
- Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| | - Helle Praetorius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
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Schramm A, Schweda F, Sequeira-Lopez MLS, Hofmann F, Sandner P, Schlossmann J. Protein Kinase G Is Involved in Acute but Not in Long-Term Regulation of Renin Secretion. Front Pharmacol 2019; 10:800. [PMID: 31379575 PMCID: PMC6657341 DOI: 10.3389/fphar.2019.00800] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/21/2019] [Indexed: 12/27/2022] Open
Abstract
Pharmacological inhibition of the renin–angiotensin–aldosterone system (RAAS) is, in combination with diuretics, the first-choice treatment for hypertension, although 10–20% of patients do not respond adequately. Next to the RAAS, the nitric oxide/cGMP/protein kinase G (PKG) system is the second fundamental blood pressure regulator. Whether both systems influence each other is not well-studied. It has been shown that nitric oxide (NO) supports renin recruitment via activation of soluble guanylate cyclase (sGC) and subsequent generation of cGMP. Whether this leads to an ensuing activation of PKGs in this context is not known. PKGIα, as well as PKGII, is expressed in renin-producing cells. Hence, we analyzed whether these enzymes play a role regarding renin synthesis, secretion, or recruitment. We generated renin-cell-specific PKGI-knockout mice and either stimulated or inhibited the renin system in these mice by salt diets. To exclude the possibility that one kinase isoform can compensate the lack of the other, we also studied double-knockout animals with a conditional knockout of PKGI in juxtaglomerular cells (JG cells) and a ubiquitous knockout of PKGII. We analyzed blood pressure, renin mRNA and renal renin protein content as well as plasma renin concentration. Furthermore, we stimulated the cGMP system in these mice using BAY 41-8543, an sGC stimulator, and examined renin regulation either after acute administration or after 7 days (application once daily). We did not reveal any striking differences regarding long-term renin regulation in the studied mouse models. Yet, when we studied the acute effect of BAY 41-8543 on renin secretion in isolated perfused kidneys as well as in living animals, we found that the administration of the substance led to a significant increase in plasma renin concentration in control animals. This effect was completely abolished in double-knockout animals. However, after 7 days of once daily application, we did not detect a persistent increase in renin mRNA or protein in any studied genotype. Therefore, we conclude that in mice, cGMP and PKG are involved in the acute regulation of renin release but have no influence on long-term renin adjustment.
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Affiliation(s)
- Andrea Schramm
- Institute of Pharmacy, Department of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | | | - Franz Hofmann
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
| | - Peter Sandner
- Bayer AG, Drug Discovery-Cardiology, Wuppertal, Germany
| | - Jens Schlossmann
- Institute of Pharmacy, Department of Pharmacology and Toxicology, University of Regensburg, Regensburg, Germany
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8
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Rosenbaek JB, Pedersen EB, Bech JN. The effect of sodium nitrite infusion on renal function, brachial and central blood pressure during enzyme inhibition by allopurinol, enalapril or acetazolamide in healthy subjects: a randomized, double-blinded, placebo-controlled, crossover study. BMC Nephrol 2018; 19:244. [PMID: 30241504 PMCID: PMC6150994 DOI: 10.1186/s12882-018-1035-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/03/2018] [Indexed: 12/25/2022] Open
Abstract
Background Sodium nitrite (NaNO2) causes vasodilation, presumably by enzymatic conversion to nitric oxide (NO). Several enzymes with nitrite reducing capabilities have been discovered in vitro, but their relative importance in vivo has not been investigated. We aimed to examine the effects of NaNO2 on blood pressure, fractional sodium excretion (FENa), free water clearance (CH2O) and GFR, after pre-inhibition of xanthine oxidase, carbonic anhydrase, and angiotensin-converting enzyme. The latter as an approach to upregulate endothelial NO synthase activity. Methods In a double-blinded, placebo-controlled, crossover study, 16 healthy subjects were treated, in a randomized order, with placebo, allopurinol 150 mg twice daily (TD), enalapril 5 mg TD, or acetazolamide 250 mg TD. After 4 days of treatment and standardized diet, the subjects were examined at our lab. During intravenous infusion of 240 μg NaNO2/kg/hour for 2 h, we measured changes in brachial and central blood pressure (BP), plasma cyclic guanosine monophosphate (P-cGMP), plasma and urine osmolality, GFR by 51Cr-EDTA clearance, FENa and urinary excretion rate of cGMP (U-cGMP) and nitrite and nitrate (U-NOx). Subjects were supine and orally water-loaded throughout the examination day. Results Irrespective of pretreatment, we observed an increase in FENa, heart rate, U-NOx, and a decrease in CH2O and brachial systolic BP during NaNO2 infusion. P-cGMP and U-cGMP did not change during infusion. We observed a consistent trend towards a reduction in central systolic BP, which was only significant after allopurinol. Conclusion This study showed a robust BP lowering, natriuretic and anti-aquaretic effect of intravenous NaNO2 regardless of preceding enzyme inhibition. None of the three enzyme inhibitors used convincingly modified the pharmacological effects of NaNO2. The steady cGMP indicates little or no conversion of nitrite to NO. Thus the effect of NaNO2 may not be mediated by NO generation. Trial registration EU Clinical Trials Register, 2013-003404-39. Registered December 3 2013.
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Affiliation(s)
- Jeppe B Rosenbaek
- University Clinic in Nephrology and Hypertension, Regional Hospital West Jutland and Aarhus University, Laegaardvej 12J, DK-7500, Holstebro, Denmark.
| | - Erling B Pedersen
- University Clinic in Nephrology and Hypertension, Regional Hospital West Jutland and Aarhus University, Laegaardvej 12J, DK-7500, Holstebro, Denmark
| | - Jesper N Bech
- University Clinic in Nephrology and Hypertension, Regional Hospital West Jutland and Aarhus University, Laegaardvej 12J, DK-7500, Holstebro, Denmark
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Polcari AJ, Farooq AV, Woods ME, Ripsch MS, Picken M, Turk TMT, White FA. Effect of the phosphodiesterase-5 inhibitor zaprinast on ischemia-reperfusion injury in rats. J Endourol 2013; 27:338-42. [PMID: 22974473 DOI: 10.1089/end.2012.0198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The cardiac and renal protective effects of phosphodiesterase-5 (PDE-5) inhibitors against ischemia-reperfusion injury have recently been demonstrated in animal studies. We evaluated the effect of pretreatment with the PDE-5 inhibitor zaprinast on warm renal ischemia in a rat model. METHODS Female Sprague-Dawley rats underwent concomitant right nephrectomy and left renal hilar occlusion for 30 minutes. Twelve animals were equally divided into three groups: Group 1 received no pharmacologic pretreatment, group 2 was pretreated with zaprinast 10 mg/kg, and group 3 was pretreated with zaprinast 20 mg/kg. Zaprinast was dissolved in 25% dimethyl sulfoxide and given as a single intraperitoneal injection 30 minutes before surgery. Serum blood urea nitrogen (BUN) and creatinine levels, histopathology, and TUNEL staining for apoptosis were assessed 24 hours postoperatively. RESULTS The mean creatinine level for groups 1, 2, and 3 was 0.73 mg/dL, 0.55 mg/dL, and 0.38 mg/dL, respectively. These values were not statistically different (P=0.099). The mean BUN levels of 35.8 mg/dL for group 1, 27.3 mg/dL for group 2, and 23.3 mg/dL for group 3 were also statistically similar (P=0.278). There were no objective differences in histopathologic evaluation or TUNEL staining between the groups. CONCLUSION This study did not demonstrate a beneficial effect of zaprinast pretreatment on renal parameters after warm ischemic injury.
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Affiliation(s)
- Anthony J Polcari
- Department of Urology and Pathology, 4 Loyola University Medical Center, Maywood, IL 60153, USA.
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Thoonen R, Sips PY, Bloch KD, Buys ES. Pathophysiology of hypertension in the absence of nitric oxide/cyclic GMP signaling. Curr Hypertens Rep 2013; 15:47-58. [PMID: 23233080 DOI: 10.1007/s11906-012-0320-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signaling system is a well-characterized modulator of cardiovascular function, in general, and blood pressure, in particular. The availability of mice mutant for key enzymes in the NO-cGMP signaling system facilitated the identification of interactions with other blood pressure modifying pathways (e.g. the renin-angiotensin-aldosterone system) and of gender-specific effects of impaired NO-cGMP signaling. In addition, recent genome-wide association studies identified blood pressure-modifying genetic variants in genes that modulate NO and cGMP levels. Together, these findings have advanced our understanding of how NO-cGMP signaling regulates blood pressure. In this review, we will summarize the results obtained in mice with disrupted NO-cGMP signaling and highlight the relevance of this pathway as a potential therapeutic target for the treatment of hypertension.
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Affiliation(s)
- Robrecht Thoonen
- Molecular Cardiology Research Institute, Molecular Cardiology Research Center, Tufts Medical Center, Boston, MA 02111, USA.
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11
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Sips PY, Buys ES. Genetic modification of hypertension by sGCα1. Trends Cardiovasc Med 2013; 23:312-8. [PMID: 23755896 DOI: 10.1016/j.tcm.2013.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/30/2013] [Accepted: 05/01/2013] [Indexed: 02/06/2023]
Abstract
Hypertension is an important modifiable risk factor for coronary heart disease, congestive heart failure, stroke, end-stage renal disease, and peripheral vascular disease, but many of the molecular mechanisms and genetic factors underlying the development of the most common forms of human hypertension remain to be defined. Abundant evidence suggests that nitric oxide (NO) and one of its primary targets, the cyclic guanosine monophosphate (cGMP)-generating enzyme soluble guanylate cyclase (sGC), have a critical role in regulating blood pressure. The availability of murine models of hypertension and the revolution in human genetics research (e.g., genome-wide association studies [GWAS]), resulting in the identification of dozens of genetic loci that affect normal variation in blood pressure and susceptibility to hypertension, provide a unique opportunity to dissect the mechanisms by which NO-cGMP signaling regulates blood pressure and to gain important insights into the pathogenesis of hypertension. In this review, we will give an overview of the current knowledge relating to the role of sGC in the regulation of blood pressure, discussing data obtained from genetically modified mouse models as well as from human genetic studies.
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Affiliation(s)
- Patrick Y Sips
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Thier 511B, Boston, MA 02114
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12
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Neubauer B, Machura K, Kettl R, Lopez MLSS, Friebe A, Kurtz A. Endothelium-derived nitric oxide supports renin cell recruitment through the nitric oxide-sensitive guanylate cyclase pathway. Hypertension 2013; 61:400-7. [PMID: 23297374 DOI: 10.1161/hypertensionaha.111.00221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chronic challenge of renin-angiotensin causes recruitment of renin-producing cells in the kidney along the media layer of afferent arterioles and hypertrophy of cells in the juxtaglomerular apparatus. This study aimed to define the role of nitric oxide (NO) with regard to the recruitment pattern of renin-producing cells and to the possible pathways along which NO could act. We considered the hypothesis that endothelium-derived NO acts via NO-sensitive guanylate cyclase. Mice were treated with low-salt diet in combination with the angiotensin I-converting enzyme inhibitor enalapril for 3 weeks, which led to a 13-fold increase in renin expression associated with marked recruitment of renin cells in afferent arterioles and hypertrophy of the juxtaglomerular apparatus in wild-type mice. In wild-type mice additionally treated with the nonselective NO synthase inhibitor L-NAME, the recruitment of renin-expressing cells along the afferent arterioles was absent and juxtaglomerular hypertrophy was diminished. An almost identical attenuation of renin cell recruitment as with L-NAME treatment in wild-type mice was found in mice lacking the endothelial isoform of NO synthase. Treatment of mice lacking NO-sensitive guanylate cyclase in renin-expressing cells and preglomerular smooth muscle cells with low-salt diet in combination with the angiotensin I-converting enzyme inhibitor enalapril for 3 weeks produced juxtaglomerular hypertrophy like in wild-type mice, but no recruitment in afferent arterioles. These findings suggest that endothelium-derived NO and concomitant formation of cGMP in preglomerular renin cell precursors supports recruitment of renin-expressing cells along preglomerular vessels, but not in the juxtaglomerular apparatus.
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Affiliation(s)
- Björn Neubauer
- Institute of Physiology, University of Regensburg, Regensburg, Germany.
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Abstract
PURPOSE OF REVIEW Despite decades of study, the pathogenesis of essential hypertension remains obscure, but the kidney appears to play a central role. Technology for manipulation of the mouse genome has been immensely valuable in dissecting pathways involved in blood pressure control. This review summarizes recent studies employing this technology to understand signaling pathways and specific cell lineages within the kidney that are involved in the regulation of sodium excretion impacting blood pressure homeostasis. RECENT FINDINGS We review a series of recent studies of regulatory pathways affecting sodium excretion by the kidney including the renin-angiotensin system, the mineralocorticoid receptor, the endothelin system, nitric oxide, and the with-no-lysine (K)/sterile 20-like kinase pathway. We have specifically highlighted studies utilizing transgenic mouse models, which provide a powerful mechanism for defining the role of proteins and pathways on sodium balance and blood pressure in the intact organism. SUMMARY These studies underscore the importance of the kidney in regulation of blood pressure and the pathogenesis of hypertension. Transgenic mouse models provide a powerful approach to identifying key cell lineages and molecular pathways causing hypertension. These pathways represent potential targets for novel antihypertensive therapies.
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Atchison DK, Beierwaltes WH. The influence of extracellular and intracellular calcium on the secretion of renin. Pflugers Arch 2012; 465:59-69. [PMID: 22538344 DOI: 10.1007/s00424-012-1107-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/03/2012] [Indexed: 12/29/2022]
Abstract
Changes in plasma, extracellular, and intracellular calcium can affect renin secretion from the renal juxtaglomerular (JG) cells. Elevated intracellular calcium directly inhibits renin release from JG cells by decreasing the dominant second messenger intracellular cyclic adenosine monophosphate (cAMP) via actions on calcium-inhibitable adenylyl cyclases and calcium-activated phosphodiesterases. Increased extracellular calcium also directly inhibits renin release by stimulating the calcium-sensing receptor (CaSR) on JG cells, resulting in parallel changes in the intracellular environment and decreasing intracellular cAMP. In vivo, acutely elevated plasma calcium inhibits plasma renin activity (PRA) via parathyroid hormone-mediated elevations in renal cortical interstitial calcium that stimulate the JG cell CaSR. However, chronically elevated plasma calcium or CaSR activation may actually stimulate PRA. This elevation in PRA may be a compensatory mechanism resulting from calcium-mediated polyuria. Thus, changing the extracellular calcium in vitro or in vivo results in inversely related acute changes in cAMP, and therefore renin release, but chronic changes in calcium may result in more complex interactions dependent upon the duration of changes and the integration of the body's response to these changes.
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Affiliation(s)
- Douglas K Atchison
- Hypertension and Vascular Research Division, Department Internal Medicine, Henry Ford Hospital, 7121 E&R Bldg., 2799 W. Grand Blvd., Detroit, MI 48202, USA
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Facemire CS, Nguyen M, Jania L, Beierwaltes WH, Kim HS, Koller BH, Coffman TM. A major role for the EP4 receptor in regulation of renin. Am J Physiol Renal Physiol 2011; 301:F1035-41. [PMID: 21835766 DOI: 10.1152/ajprenal.00054.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Prostaglandins have been implicated as paracrine regulators of renin secretion, but the specific pathways and receptor(s) carrying out these functions have not been fully elucidated. To examine the contributions of prostanoid synthetic pathways and receptors to regulation of renin in the intact animal, we used a panel of mice with targeted disruption of several key genes: cyclooxygenase-2 (COX-2), microsomal PGE synthases 1 and 2 (mPGES1, mPGES2), EP2 and EP4 receptors for PGE(2), and the IP receptor for PGI(2). To activate the macula densa signal for renin stimulation, mice were treated with furosemide over 5 days and renin mRNA levels were determined by real-time RT-PCR. At baseline, there were no differences in renin mRNA levels between wild-type and the various strains of mutant mice. Furosemide caused marked stimulation of renin mRNA expression across all groups of wild-type control mice. This response was completely abrogated in the absence of COX-2, but was unaffected in mice lacking mPGES1 or mPGES2. The absence of G(s)/cAMP-linked EP2 receptors had no effect on stimulation of renin by furosemide and there was only a modest, insignificant reduction in renin responses in mice lacking the IP receptor. By contrast, renin stimulation in EP4(-/-) mice was significantly reduced by ∼70% compared with wild-type controls. These data suggest that stimulation of renin by the macula densa mechanism is mediated by PGE(2) through a pathway requiring COX-2 and the EP4 receptor, but not EP2 or IP receptors. Surprisingly, mPGES1 or mPGES2 are not required, suggesting other alternative mechanisms for generating PGE(2) in response to macula densa stimulation.
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Affiliation(s)
- Carie S Facemire
- Division of Nephrology, Department of Medicine, Duke University and Durham Veterans Affairs Medical Centers, Durham, USA
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Kurtz A. Salt intake and the nitric oxide-cyclic AMP signaling pathway in renin secreting cells. Am J Hypertens 2010; 23:1157. [PMID: 20956962 DOI: 10.1038/ajh.2010.171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Neuronal nitric oxide synthase supports Renin release during sodium restriction through inhibition of phosphodiesterase 3. Am J Hypertens 2010; 23:1241-6. [PMID: 20651700 DOI: 10.1038/ajh.2010.153] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Mice with targeted deletion of neuronal nitric oxide (NO) synthase (nNOS⁻(/)⁻) display inability to increase plasma renin concentration (PRC) in response to sodium restriction. nNOS has a distinct expression at the macula densa (MD), and in the present study, it was tested whether nNOS supports renin release by cyclic guanosine monophosphate (cGMP)-mediated inhibition of cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase 3 (PDE3) in juxtaglomerular (JG) cells. METHODS The experiments were performed in conscious nNOS⁻(/)⁻ and wild types after 10 days on a low-sodium diet by acute treatment with the PDE3-inhibitor milrinone, the PDE5 inhibitor zaprinast, or vehicle, using a crossover study protocol. PRC was measured with the antibody-trapping technique and blood pressure with telemetry. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were estimated by measurements of inulin- and para-amino hippuric acid (PAH) clearances, respectively. RESULTS The basal PRC was reduced in nNOS⁻(/)⁻ compared to the wild types. Administration of milrinone caused a more pronounced PRC increase in nNOS⁻(/)⁻, resulting in normalized renin levels, whereas PDE5 inhibition did not affect PRC in any genotype. The blood pressure was similar in both genotypes, and milrinone did not affect blood pressure compared to vehicle. GFR and RPF were similar at baseline and were reduced by milrinone. CONCLUSIONS The present study provides in vivo evidence supporting the view that NO, selectively derived from nNOS, mediates renin release during sodium restriction by inhibiting PDE3, which would increase renin release by elevating cAMP levels in the JG cells.
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Atchison DK, Ortiz-Capisano MC, Beierwaltes WH. Acute activation of the calcium-sensing receptor inhibits plasma renin activity in vivo. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1020-6. [PMID: 20660105 PMCID: PMC2957381 DOI: 10.1152/ajpregu.00238.2010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 07/19/2010] [Indexed: 01/17/2023]
Abstract
In vitro, the renin-secreting juxtaglomerular cells express the calcium-sensing receptor, and its activation with the calcimimetic cinacalcet inhibits renin release. To test whether the activation of calcium-sensing receptor similarly inhibits plasma renin activity (PRA) in vivo, we hypothesized that the calcium-sensing receptor is expressed in juxtaglomerular cells in vivo, and acutely administered cinacalcet would inhibit renin activity in anesthetized rats. Since cinacalcet inhibits parathyroid hormone, which may stimulate renin activity, we sought to determine whether cinacalcet inhibits renin activity by decreasing parathyroid hormone. Lastly, we hypothesized that chronically administered cinacalcet would inhibit basal and stimulated renin in conscious rats. Calcium-sensing receptors and renin were localized in the same juxtaglomerular cells using immunofluorescence in rat cortical slices fixed in vivo. Cinacalcet was administered acutely via intravenous bolus in anesthetized rats and chronically in conscious rats by oral gavage. Acute administration of cinacalcet decreased basal renin activity from 13.6 ± 2.4 to 6.1 ± 1.1 ng ANG I·ml(-1)·h(-1) (P < 0.001). Likewise, cinacalcet decreased furosemide-stimulated renin from 30.6 ± 2.3 to 21.3 ± 2.3 ng ANG I·ml(-1)·h(-1) (P < 0.001). In parathyroidectomized rats, cinacalcet decreased renin activity from 9.3 ± 1.3 to 5.2 ± 0.5 ng ANG I·ml(-1)·h(-1) (P < 0.05) similar to sham-operated controls (13.5 ± 2.2 to 6.6 ± 0.8 ng ANG I·ml(-1)·h(-1), P < 0.05). Chronic administration of cinacalcet over 7 days had no significant effect on PRA under basal or stimulated conditions. In conclusion, calcium-sensing receptors are expressed in juxtaglomerular cells in vivo, and acute activation of these receptors with cinacalcet inhibits PRA in anesthetized rats, independent of parathyroid hormone.
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Affiliation(s)
- Douglas K Atchison
- Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202, USA
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Pelletier AM, Venkataramana S, Miller KG, Bennett BM, Nair DG, Lourenssen S, Blennerhassett MG. Neuronal nitric oxide inhibits intestinal smooth muscle growth. Am J Physiol Gastrointest Liver Physiol 2010; 298:G896-907. [PMID: 20338922 DOI: 10.1152/ajpgi.00259.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hyperplasia of smooth muscle contributes to the thickening of the intestinal wall that is characteristic of inflammation, but the mechanisms of growth control are unknown. Nitric oxide (NO) from enteric neurons expressing neuronal NO synthase (nNOS) might normally inhibit intestinal smooth muscle cell (ISMC) growth, and this was tested in vitro. In ISMC from the circular smooth muscle of the adult rat colon, chemical NO donors inhibited [(3)H]thymidine uptake in response to FCS, reducing this to baseline without toxicity. This effect was inhibited by the guanylyl cyclase inhibitor ODQ and potentiated by the phosphodiesterase-5 inhibitor zaprinast. Inhibition was mimicked by 8-bromo (8-Br)-cGMP, and ELISA measurements showed increased levels of cGMP but not cAMP in response to sodium nitroprusside. However, 8-Br-cAMP and cilostamide also showed inhibitory actions, suggesting an additional role for cAMP. Via a coculture model of ISMC and myenteric neurons, immunocytochemistry and image analysis showed that innervation reduced bromodeoxyuridine uptake by ISMC. Specific blockers of nNOS (7-NI, NAAN) significantly increased [(3)H]thymidine uptake in response to a standard stimulus, showing that nNOS activity normally inhibits ISMC growth. In vivo, nNOS axon number was reduced threefold by day 1 of trinitrobenzene sulfonic acid-induced rat colitis, preceding the hyperplasia of ISMC described earlier in this model. We conclude that NO can inhibit ISMC growth primarily via a cGMP-dependent mechanism. Functional evidence that NO derived from nNOS causes inhibition of ISMC growth in vitro predicts that the loss of nNOS expression in colitis contributes to ISMC hyperplasia in vivo.
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Affiliation(s)
- Anne-Marie Pelletier
- Gastrointestinal Diseases Research Unit, Queen's Univ., 76 Stuart St., Kingston, Ontario K7L 2V6
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Castrop H, Höcherl K, Kurtz A, Schweda F, Todorov V, Wagner C. Physiology of Kidney Renin. Physiol Rev 2010; 90:607-73. [PMID: 20393195 DOI: 10.1152/physrev.00011.2009] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Armin Kurtz
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Frank Schweda
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Vladimir Todorov
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Charlotte Wagner
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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Beierwaltes WH. The role of calcium in the regulation of renin secretion. Am J Physiol Renal Physiol 2010; 298:F1-F11. [PMID: 19640903 PMCID: PMC2806121 DOI: 10.1152/ajprenal.00143.2009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 07/23/2009] [Indexed: 12/20/2022] Open
Abstract
Renin is the enzyme which is the rate-limiting step in the formation of the hormone angiotensin II. Therefore, the regulation of renin secretion is critical in understanding the control of the renin-angiotensin-aldosterone system and its many biological and pathological actions. Renin is synthesized, stored in, and released from the juxtaglomerular (JG) cells of the kidney. While renin secretion is positively regulated by the "second messenger" cAMP, unlike most secretory cells, renin secretion from the JG cell is inversely related to the extracellular and intracellular calcium concentrations. This novel relationship is referred to as the "calcium paradox." This review will address observations made over the past 30 years regarding calcium and the regulation of renin secretion, and focus on recent observations which address this scientific conundrum. These include 1) receptor-mediated pathways for changing intracellular calcium; 2) the discovery of a calcium-inhibitable isoform of adenylyl cyclase associated with renin in the JG cells; 3) calcium-sensing receptors in the JG cells; 4) calcium-calmodulin-mediated signals; 5) the role of phosphodiesterases; and 6) connexins, gap junctions, calcium waves, and the cortical extracellular calcium environment. While cAMP is the dominant second messenger for renin secretion, calcium appears to modulate the integrated activities of the enzymes, which balance cAMP synthesis and degradation. Thus this review concludes that calcium modifies the amplitude of cAMP-mediated renin-signaling pathways. While calcium does not directly control renin secretion, increased calcium inhibits and decreased calcium amplifies cAMP-stimulated renin secretion.
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Affiliation(s)
- William H Beierwaltes
- Dept. of Medicine, Hypertension and Vascular Research Div, Henry Ford Hospital, 7121 E&R Bldg, 2799 W. Grand Blvd, Detroit, MI 48202, USA.
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Yingst DR, Araghi A, Doci TM, Mattingly R, Beierwaltes WH. Decreased renal perfusion rapidly increases plasma membrane Na-K-ATPase in rat cortex by an angiotensin II-dependent mechanism. Am J Physiol Renal Physiol 2009; 297:F1324-9. [PMID: 19726543 DOI: 10.1152/ajprenal.90363.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To understand how rapid changes in blood pressure can regulate Na-K-ATPase in the kidney cortex, we tested the hypothesis that a short-term (5 min) decrease in renal perfusion pressure will increase the amount of Na-K-ATPase in the plasma membranes by an angiotensin II-dependent mechanism. The abdominal aorta of anesthetized Sprague-Dawley rats was constricted with a ligature between the renal arteries, and pressure was monitored on either side during acute constriction. Left renal perfusion pressure was reduced to 70 +/- 1 mmHg (n = 6), whereas right renal perfusion pressure was 112 +/- 4 mmHg. In control (nonconstricted) rats (n = 5), pressure to both kidneys was similar at 119 +/- 6 mmHg. After 5 min of reduced perfusion, femoral venous samples were taken for plasma renin activity (PRA) and the kidneys excised. The cortex was dissected, minced, sieved, and biotinylated. Lower perfusion left kidneys showed a 41% increase (P < 0.003) in the amount of Na-K-ATPase in the plasma membrane compared with right kidneys. In controls, there was no difference in cell surface Na-K-ATPase between left and right kidneys (P = 0.47). PRA was 57% higher in experimental animals compared with controls. To test the role of angiotensin II in mediating the increase in Na-K-ATPase, we repeated the experiments (n = 6) in rats treated with ramiprilat. When angiotensin-converting enzyme was inhibited, the cell surface Na-K-ATPase of the two kidneys was equal (P =0.46). These results confirm our hypothesis: rapid changes in blood pressure regulate trafficking of Na-K-ATPase in the kidney cortex.
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Affiliation(s)
- Douglas R Yingst
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Abstract
The renin-angiotensin system (RAS) is critically involved in the regulation of the salt and volume status of the body and blood pressure. The activity of the RAS is controlled by the protease renin, which is released from the renal juxtaglomerular epithelioid cells into the circulation. Renin release is regulated in negative feedback-loops by blood pressure, salt intake, and angiotensin II. Moreover, sympathetic nerves and renal autacoids such as prostaglandins and nitric oxide stimulate renin secretion. Despite numerous studies there remained substantial gaps in the understanding of the control of renin release at the organ or cellular level. Some of these gaps have been closed in the last years by means of gene-targeted mice and advanced imaging and electrophysiological methods. In our review, we discuss these recent advances together with the relevant previous literature on the regulation of renin release.
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Herget S, Lohse MJ, Nikolaev VO. Real-time monitoring of phosphodiesterase inhibition in intact cells. Cell Signal 2008; 20:1423-31. [PMID: 18467075 DOI: 10.1016/j.cellsig.2008.03.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Revised: 03/04/2008] [Accepted: 03/12/2008] [Indexed: 01/17/2023]
Abstract
Phosphodiesterases (PDEs) are hydrolytic enzymes, which convert cyclic AMP (cAMP) and cyclic GMP (cGMP) into their corresponding monophosphates. PDE-dependent hydrolysis shape gradients of these second messengers in cells, which may form the basis of their compartmentation and play a key role in a vast number of physiological and pathological processes. Here, we present a novel approach for real-time monitoring of local cAMP and cGMP levels associated with particular PDEs. We used HEK 293 cells expressing genetic constructs encoding a PDE of interest (PDE3A, PDE4A1 or PDE5A) fused to cAMP and cGMP sensors, which allow to directly visualize changes in cyclic nucleotide concentrations in the vicinity of PDE molecules by fluorescence resonance energy transfer (FRET). FRET was detected by imaging of single cells on 96-well plates and demonstrated specific effects of PDE inhibitors on local cyclic nucleotide levels. In addition, this approach reported physiological regulation of PDE3A activity, its activation by PKA-dependent phosphorylation and inhibition by cGMP. In conclusion, our assay provides a unique and highly sensitive method to analyze PDE activity in living cells. It allows to sense cAMP gradients around particular PDE molecules and to study the pharmacological effects of selective inhibitors on localized cAMP signalling.
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Affiliation(s)
- Sabine Herget
- Institute of Pharmacology and Toxicology, University of Würzburg, 97078 Würzburg, Germany
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Pentz ES, Lopez MLSS, Cordaillat M, Gomez RA. Identity of the renin cell is mediated by cAMP and chromatin remodeling: an in vitro model for studying cell recruitment and plasticity. Am J Physiol Heart Circ Physiol 2007; 294:H699-707. [PMID: 18055510 DOI: 10.1152/ajpheart.01152.2007] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The renin-angiotensin system (RAS) regulates blood pressure and fluid-electrolyte homeostasis. A key step in the RAS cascade is the regulation of renin synthesis and release by the kidney. We and others have shown that a major mechanism to control renin availability is the regulation of the number of cells capable of making renin. The kidney possesses a pool of cells, mainly in its vasculature but also in the glomeruli, capable of switching from smooth muscle to endocrine renin-producing cells when homeostasis is threatened. The molecular mechanisms governing the ability of these cells to turn the renin phenotype on and off have been very difficult to study in vivo. We, therefore, developed an in vitro model in which cells of the renin lineage are labeled with cyan fluorescent protein and cells actively making renin mRNA are labeled with yellow fluorescent protein. The model allowed us to determine that it is possible to culture cells of the renin lineage for numerous passages and that the memory to express the renin gene is maintained in culture and can be reenacted by cAMP and chromatin remodeling (histone H4 acetylation) at the cAMP-responsive element in the renin gene.
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Affiliation(s)
- Ellen Steward Pentz
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Compartmentalized cAMP signalling in regulated exocytic processes in non-neuronal cells. Cell Signal 2007; 20:590-601. [PMID: 18061403 DOI: 10.1016/j.cellsig.2007.10.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 10/16/2007] [Indexed: 01/04/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) is a central second messenger controlling a plethora of vital functions. Studies of cAMP dynamics in living cells have revealed markedly inhomogeneous concentrations of the second messenger in different compartments. Moreover, cAMP effectors such as cAMP-dependent protein kinase (PKA) and cAMP-activated GTP-exchange factors (Epacs) are tethered to specific cellular sites. Both the tailoring of cAMP concentrations, and the activities of cAMP-dependent signalling systems at specific cellular locations are prerequisites for most, if not all, cAMP-dependent processes. This review focuses on the role of compartmentalized cAMP signalling in exocytic processes in non-neuronal cells. Particularly, the insertion of aquaporin-2 into the plasma membrane of renal principal cells as an example for a cAMP-dependent exocytic process in a non-secretory cell type, renin secretion from juxtaglomerular cells as a cAMP-triggered exocytosis from an endocrine cell, insulin release from pancreatic beta-cells as a Ca2+-mediated and cAMP-potentiated exocytic processes in an endocrine cell, and cAMP- or Ca2+ -triggered H+ secretion from gastric parietal cells as an exocytic process in an exocrine cell are discussed. The selected examples of cAMP-regulated exocytic pathways are reviewed with regard to key proteins involved: adenylyl cyclases, phosphodiesterases, PKA, A kinase anchoring proteins (AKAPs) and Epacs.
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