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Thongsepee N, Himakhun W, Kankul K, Martviset P, Chantree P, Sornchuer P, Ruangtong J, Hiranyachattada S. Monosodium glutamate altered renal architecture and modulated expression of NMDA-R, eNOS, and nNOS in normotensive and hypertensive rats. Food Chem Toxicol 2024; 189:114763. [PMID: 38797315 DOI: 10.1016/j.fct.2024.114763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Monosodium glutamate (MSG) administration has been shown to pronounce hypertension and oxidative status with increased renal blood flow (RBF), however, the precise mechanisms of action have never been demonstrated. This study aimed to investigate the MSG action by studying the alteration in renal architecture and specific protein expression in 2-kidney-1-clip hypertensive comparing to sham operative normotensive rats. The administered doses of MSG were 80, 160, or 320 mg/kg BW daily for 8 weeks. Using routine chemical staining, the congestion of glomerular capillaries, a lesser renal corpuscles and glomeruli size, a widen Bowman capsule's space, an increase in mesangial cell proliferation and mesangial matrix, renal interstitial fibrosis, focal cloudy swelling of renal tubular epithelial cells were observed. Immunological study revealed an increase in the expression of N-methyl-D-aspartate receptor (NMDA-R) and endothelial nitric oxide synthase (eNOS) but a decrease in neuronal NOS (nNOS). It is suggested that MSG may upregulate the NMDA-R levels which responsible for the oxidative stress, glomerular injury, and renal interstitial fibrosis. The NMDA-R may also stimulate eNOS overexpression which resulted in renal microvascular dilatation, a raise in RBF and GFR, and natriuresis and diuresis promotion. Long-term exposure of MSG may trigger adaptation of tubuloglomerular feedback through nNOS downregulation.
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Affiliation(s)
- Nattaya Thongsepee
- Department of Preclinical Science, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand; Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand.
| | - Wanwisa Himakhun
- Department of Pathology, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand
| | - Kanokwan Kankul
- Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand
| | - Pongsakorn Martviset
- Department of Preclinical Science, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand; Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand
| | - Pathanin Chantree
- Department of Preclinical Science, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand; Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand
| | - Phornphan Sornchuer
- Department of Preclinical Science, Faculty of Medicine, Thammasat University, Pathum Thani, 12120, Thailand; Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand
| | - Jittiporn Ruangtong
- Research Unit in Nutraceuticals and Food Safety, Thammasat University, Pathum Thani, 12120, Thailand
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Nair PC, Mangoni AA, Rodionov RN. Redefining the biological and pathophysiological role of dimethylarginine dimethylaminohydrolase 2. Trends Mol Med 2024; 30:552-561. [PMID: 38553332 DOI: 10.1016/j.molmed.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 06/15/2024]
Abstract
The enzyme dimethylarginine dimethylaminohydrolase (DDAH) 1 metabolizes asymmetric dimethylarginine (ADMA), a critical endogenous cardiovascular risk factor. In the past two decades, there has been significant controversy about whether DDAH2, the other DDAH isoform, is also able to directly metabolize ADMA. There has been evidence that DDAH2 regulates several critical processes involved in cardiovascular and immune homeostasis. However, the molecular mechanisms underpinning these effects are unclear. In this opinion, we discuss the previous and current knowledge of ADMA metabolism by DDAH in light of a recent consortium study, which convincingly demonstrated that DDAH2 is not capable of metabolizing ADMA, unlike DDAH1. Thus, further research in this field is needed to uncover the molecular mechanisms of DDAH2 and its role in various disorders.
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Affiliation(s)
- Pramod C Nair
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia; Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia; South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, SA, Australia; Discipline of Medicine, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.
| | - Arduino A Mangoni
- Discipline of Clinical Pharmacology, College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia; Department of Clinical Pharmacology, Flinders Medical Centre, Southern Adelaide Local Health Network, Bedford Park, SA, Australia
| | - Roman N Rodionov
- Department of Internal Medicine III, Technische Universität Dresden, Dresden, Germany
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3
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Liu R, Juncos LA, Lu Y, Wei J, Zhang J, Wang L, Lai EY, Carlstrom M, Persson AEG. The Role of Macula Densa Nitric Oxide Synthase 1 Beta Splice Variant in Modulating Tubuloglomerular Feedback. Compr Physiol 2023; 13:4215-4229. [PMID: 36715280 PMCID: PMC9990375 DOI: 10.1002/cphy.c210043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Abnormalities in renal electrolyte and water excretion may result in inappropriate salt and water retention, which facilitates the development and maintenance of hypertension, as well as acid-base and electrolyte disorders. A key mechanism by which the kidney regulates renal hemodynamics and electrolyte excretion is via tubuloglomerular feedback (TGF), an intrarenal negative feedback between tubules and arterioles. TGF is initiated by an increase of NaCl delivery at the macula densa cells. The increased NaCl activates luminal Na-K-2Cl cotransporter (NKCC2) of the macula densa cells, which leads to activation of several intracellular processes followed by the production of paracrine signals that ultimately result in a constriction of the afferent arteriole and a tonic inhibition of single nephron glomerular filtration rate. Neuronal nitric oxide (NOS1) is highly expressed in the macula densa. NOS1β is the major splice variant and accounts for most of NO generation by the macula densa, which inhibits TGF response. Macula densa NOS1β-mediated modulation of TGF responses plays an essential role in control of sodium excretion, volume and electrolyte hemostasis, and blood pressure. In this article, we describe the mechanisms that regulate macula densa-derived NO and their effect on TGF response in physiologic and pathologic conditions. © 2023 American Physiological Society. Compr Physiol 13:4215-4229, 2023.
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Affiliation(s)
- Ruisheng Liu
- Department of Molecular Pharmacology & Physiology
- Hypertension and Kidney Research Center, Morsani College of Medicine, University of South Florida, Tampa, FL
| | - Luis A. Juncos
- Department of Internal Medicine, Central Arkansas Veterans Healthcare System, Little Rock, AR
| | - Yan Lu
- Division of Nephrology, University of Alabama at Birmingham, Birmingham AL
| | - Jin Wei
- Department of Molecular Pharmacology & Physiology
| | - Jie Zhang
- Department of Molecular Pharmacology & Physiology
| | - Lei Wang
- Department of Molecular Pharmacology & Physiology
| | - En Yin Lai
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou, China
| | - Mattias Carlstrom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - A. Erik G Persson
- Division of Integrative Physiology, Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Kuang R, O'Keefe SJD, Ramos Del Aguila de Rivers C, Koutroumpakis F, Binion DG. Is Salt at Fault? Dietary Salt Consumption and Inflammatory Bowel Disease. Inflamm Bowel Dis 2023; 29:140-150. [PMID: 35380668 DOI: 10.1093/ibd/izac058] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Indexed: 02/05/2023]
Abstract
Epidemiological trends have led to a growing consensus that diet plays a central role in the etiopathogenesis of inflammatory bowel diseases (IBD). A Western diet high in ultra-processed foods has been associated with an increased prevalence of IBD worldwide. Much attention has focused on components of the Western diet, including the high fat content, lack of fiber, added sugars, and use of additives, such as carrageenan and other emulsifiers. Less attention has been paid to the impact of high salt intake, an integral component of ultra-processed foods, which has increased dramatically in the US diet over the past 50 years. We review a growing body of literature linking the rise in dietary salt intake with the epidemiology of IBD, increased consumption of salt as a component of ultra-processed foods, high salt intake and imbalances in immune homeostasis, the effects of a high-salt diet on other inflammatory disorders, salt's impact on animal colitis models, salt as an underrecognized component in diet modification-induced remission of IBD, and directions for future investigation.
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Affiliation(s)
- Rebecca Kuang
- University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Stephen J D O'Keefe
- University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center (UPMC) Presbyterian Hospital, Pittsburgh, PA, USA
| | | | - Filippos Koutroumpakis
- University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center (UPMC) Presbyterian Hospital, Pittsburgh, PA, USA
| | - David G Binion
- University of Pittsburgh School of Medicine, University of Pittsburgh Medical Center (UPMC) Presbyterian Hospital, Pittsburgh, PA, USA
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Sodium Intake as a Cardiovascular Risk Factor: A Narrative Review. Nutrients 2021; 13:nu13093177. [PMID: 34579054 PMCID: PMC8470268 DOI: 10.3390/nu13093177] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/05/2021] [Accepted: 09/10/2021] [Indexed: 01/11/2023] Open
Abstract
While sodium is essential for human homeostasis, current salt consumption far exceeds physiological needs. Strong evidence suggests a direct causal relationship between sodium intake and blood pressure (BP) and a modest reduction in salt consumption is associated with a meaningful reduction in BP in hypertensive as well as normotensive individuals. Moreover, while long-term randomized controlled trials are still lacking, it is reasonable to assume a direct relationship between sodium intake and cardiovascular outcomes. However, a consensus has yet to be reached on the effectiveness, safety and feasibility of sodium intake reduction on an individual level. Beyond indirect BP-mediated effects, detrimental consequences of high sodium intake are manifold and pathways involving vascular damage, oxidative stress, hormonal alterations, the immune system and the gut microbiome have been described. Globally, while individual response to salt intake is variable, sodium should be perceived as a cardiovascular risk factor when consumed in excess. Reduction of sodium intake on a population level thus presents a potential strategy to reduce the burden of cardiovascular disease worldwide. In this review, we provide an update on the consequences of salt intake on human health, focusing on BP and cardiovascular outcomes as well as underlying pathophysiological hypotheses.
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He FJ, Tan M, Ma Y, MacGregor GA. Salt Reduction to Prevent Hypertension and Cardiovascular Disease: JACC State-of-the-Art Review. J Am Coll Cardiol 2020; 75:632-647. [PMID: 32057379 DOI: 10.1016/j.jacc.2019.11.055] [Citation(s) in RCA: 257] [Impact Index Per Article: 64.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/04/2019] [Accepted: 11/19/2019] [Indexed: 12/21/2022]
Abstract
There is strong evidence for a causal relationship between salt intake and blood pressure. Randomized trials demonstrate that salt reduction lowers blood pressure in both individuals who are hypertensive and those who are normotensive, additively to antihypertensive treatments. Methodologically robust studies with accurate salt intake assessment have shown that a lower salt intake is associated with a reduced risk of cardiovascular disease, all-cause mortality, and other conditions, such as kidney disease, stomach cancer, and osteoporosis. Multiple complex and interconnected physiological mechanisms are implicated, including fluid homeostasis, hormonal and inflammatory mechanisms, as well as more novel pathways such as the immune response and the gut microbiome. High salt intake is a top dietary risk factor. Salt reduction programs are cost-effective and should be implemented or accelerated in all countries. This review provides an update on the evidence relating salt to health, with a particular focus on blood pressure and cardiovascular disease, as well as the potential mechanisms.
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Affiliation(s)
- Feng J He
- Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
| | - Monique Tan
- Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Yuan Ma
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Graham A MacGregor
- Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
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Wetzel MD, Gao T, Stanley K, Cooper TK, Morris SM, Awad AS. Enhancing kidney DDAH-1 expression by adenovirus delivery reduces ADMA and ameliorates diabetic nephropathy. Am J Physiol Renal Physiol 2020; 318:F509-F517. [PMID: 31904280 PMCID: PMC7052661 DOI: 10.1152/ajprenal.00518.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/13/2019] [Accepted: 12/19/2019] [Indexed: 02/07/2023] Open
Abstract
Endothelial dysfunction, characterized by reduced bioavailability of nitric oxide and increased oxidative stress, is a hallmark characteristic in diabetes and diabetic nephropathy (DN). High levels of asymmetric dimethylarginine (ADMA) are observed in several diseases including DN and are a strong prognostic marker for cardiovascular events in patients with diabetes and end-stage renal disease. ADMA, an endogenous endothelial nitric oxide synthase (NOS3) inhibitor, is selectively metabolized by dimethylarginine dimethylaminohydrolase (DDAH). Low DDAH levels have been associated with cardiac and renal dysfunction, but its effects on DN are unknown. We hypothesized that enhanced renal DDAH-1 expression would improve DN by reducing ADMA and restoring NOS3 levels. DBA/2J mice injected with multiple low doses of vehicle or streptozotocin were subsequently injected intrarenally with adenovirus expressing DDAH-1 (Ad-h-DDAH-1) or vector control [Ad-green fluorescent protein (GFP)], and mice were followed for 6 wk. Diabetes was associated with increased kidney ADMA and reduced kidney DDAH activity and DDAH-1 expression but had no effect on kidney DDAH-2 expression. Ad-GFP-treated diabetic mice showed significant increases in albuminuria, histological changes, glomerular macrophage recruitment, inflammatory cytokine and fibrotic markers, kidney ADMA levels, and urinary thiobarbituric acid reactive substances excretion as an indicator of oxidative stress, along with a significant reduction in kidney DDAH activity and kidney NOS3 mRNA compared with normal mice. In contrast, Ad-h-DDAH-1 treatment of diabetic mice reversed these effects. These data indicate, for the first time, that DDAH-1 mediates renal tissue protection in DN via the ADMA-NOS3-interaction. Enhanced renal DDAH-1 activity could be a novel therapeutic tool for treating patients with diabetes.
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Affiliation(s)
- Michael D Wetzel
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Ting Gao
- Department of Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Kristen Stanley
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Timothy K Cooper
- Department of Comparative Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
| | - Sidney M Morris
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alaa S Awad
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas
- Department of Medicine, Penn State University College of Medicine, Hershey, Pennsylvania
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8
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Ibarra ME, Albertoni Borghese MF, Majowicz MP, Ortiz MC, Loidl F, Rey-Funes M, Di Ciano LA, Ibarra FR. Concerted regulation of renal plasma flow and glomerular filtration rate by renal dopamine and NOS I in rats on high salt intake. Physiol Rep 2017; 5:e13202. [PMID: 28351967 PMCID: PMC5371567 DOI: 10.14814/phy2.13202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/05/2017] [Accepted: 02/20/2017] [Indexed: 11/24/2022] Open
Abstract
Under high sodium intake renal dopamine (DA) increases while NOS I expression in macula densa cells (MD) decreases. To explore whether renal DA and NOS I, linked to natriuresis and to the stability of the tubuloglomerular feedback, respectively, act in concert to regulate renal plasma flow (RPF) and glomerular filtration rate (GFR). Male Wistar rats were studied under a normal sodium intake (NS, NaCl 0.24%) or a high sodium intake (HS, NaCl 1% in drinking water) during the 5 days of the study. For the last two days, the specific D1-like receptor antagonist SCH 23390 (1 mg kg bwt-1 day-1, sc) or a vehicle was administered. HS intake increased natriuresis, diuresis, and urinary DA while it decreased cortical NOS I expression (P < 0.05 vs. NS), Nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in MD (P < 0.001 vs. NS) and cortical nitrates+nitrites (NOx) production (NS 2.04 ± 0.22 vs. HS 1.28 ± 0.10 nmol mg protein-1, P < 0.01). Treatment with SCH 23390 to rats on HS sharply decreased hydroelectrolyte excretion (P < 0.001 vs. HS) while NOS I expression, NADPH-d activity and NOx production increased (P < 0.05 vs. HS for NOS I and P < 0.001 vs. HS for NADPH-d and NOx). SCH 23390 increased RPF and GFR in HS rats (P < 0.01 HS+SCH vs. HS). It did not cause variations in NS rats. Results indicate that when NS intake is shifted to a prolonged high sodium intake, renal DA through the D1R, and NOS I in MD cells act in concert to regulate RPF and GFR to stabilize the delivery of NaCl to the distal nephron.
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Affiliation(s)
- Mariano E Ibarra
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Maria F Albertoni Borghese
- Cátedra de Biología Celular y Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mónica P Majowicz
- Cátedra de Biología Celular y Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María C Ortiz
- Cátedra de Biología Celular y Molecular, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Fabián Loidl
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Manuel Rey-Funes
- Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Luis A Di Ciano
- Laboratorio de Riñón, Instituto de Investigaciones Médicas A. Lanari Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Fernando R Ibarra
- Laboratorio de Riñón, Instituto de Investigaciones Médicas A. Lanari Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Ciencias Fisiológicas, Facultad de Medicina Universidad de Buenos Aires, Buenos Aires, Argentina
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Kalantari S, Nafar M, Samavat S, Parvin M, Nobakht M Gh BF, Barzi F. 1 H NMR-based metabolomics exploring urinary biomarkers correlated with proteinuria in focal segmental glomerulosclerosis: a pilot study. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:821-826. [PMID: 27320161 DOI: 10.1002/mrc.4460] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/22/2016] [Accepted: 05/10/2016] [Indexed: 05/24/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a common glomerulonephritis, and its rates of occurrence are increasing worldwide. Proteinuria is a clinical defining feature of FSGS which correlates with the severity of podocyte injury in patients with nephrotic-range protein excretion. Metabolite biomarkers corresponding with the level of proteinuria could be considered as non-invasive complementary prognostic factors to proteinuria. The urine samples of 15 patients (n = 6 women and n = 9 men) with biopsy-proven FSGS were collected and subjected to nuclear magnetic resonance (NMR) analysis for metabolite profiling. Multivariate statistical analyses, including principal component analysis and orthogonal projection to latent structure discriminant analysis, were applied to construct a predictive model based on patients with proteinuria >3000 mg/day and <3000 mg/day. In addition, random forest was performed to predict differential metabolites, and pathway analysis was performed to find the defective pathways responsible for proteinuria. Ten metabolites, significant in both statistical methods (orthogonal projection to latent structure discriminant analysis and random forest), were considered as prognostic biomarkers for FSGS: citrulline, dimethylamine, proline, acetoacetate, alpha-ketoisovaleric acid, valine, isobutyrate, D-Palmitylcarnitine, histidine, and N-methylnicotinamide. Pathway analysis revealed impairment of the branched-chain amino acid degradation pathways in patients with massive proteinuria. This study shows that metabolomics can reveal the molecular changes corresponding with disease progression in patients with FSGS and provide a new insight for pathogenic pathways. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Shiva Kalantari
- Chronic Kidney Disease Research Center, Labbafinejad Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Nafar
- Chronic Kidney Disease Research Center, Labbafinejad Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shiva Samavat
- Department of Nephrology, Shahid Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahmoud Parvin
- Department of Pathology, Shahid Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - B Fatemeh Nobakht M Gh
- Department of Basic Science, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farnaz Barzi
- Department of Nephrology, Emam Hosein Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Affiliation(s)
- Michael S Lipkowitz
- Division of Nephrology & Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University Medical Center, Washington, DC
| | - Christopher S Wilcox
- Division of Nephrology & Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University Medical Center, Washington, DC.
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Liu G, Hitomi H, Rahman A, Nakano D, Mori H, Masaki T, Ma H, Iwamoto T, Kobori H, Nishiyama A. High sodium augments angiotensin II-induced vascular smooth muscle cell proliferation through the ERK 1/2-dependent pathway. Hypertens Res 2013; 37:13-8. [PMID: 24026042 DOI: 10.1038/hr.2013.108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 05/22/2013] [Accepted: 05/28/2013] [Indexed: 01/19/2023]
Abstract
Angiotensin II (Ang II)-induced vascular injury is exacerbated by high-salt diets. This study examined the effects of high-sodium level on Ang II-induced cell proliferation in rat vascular smooth muscle cells (VSMCs). The cells were cultured in a standard medium containing 137.5 mmol l(-1) of sodium. The high-sodium medium (140 mmol l(-1)) contained additional sodium chloride. Extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was determined by western blot analysis. Cell proliferation was evaluated by [(3)H]-thymidine incorporation. Ang II (100 nmol l(-1)) significantly increased ERK 1/2 phosphorylation and cell proliferation in the both medium containing standard sodium and high sodium. High-sodium level augmented Ang II-induced ERK 1/2 phosphorylation and cell proliferation compared with standard sodium. Pre-treatment with candesartan (1 μmol l(-1), Ang II type 1 receptor blocker) or PD98095 (10 μmol l(-1), ERK kinase iinhibitor) abolished the proliferative effect induced by high sodium/Ang II. Pre-treatment with 5-N,N-hexamethylene amiloride (30 μmol l(-1), Na(+)/H(+) exchanger type 1 (NHE-1) inhibitor), but not SN-6 (10 μmol l(-1), Na(+)/Ca(2+) exchanger inhibitor) or ouabain (1 mmol l(-1), Na(+)/K(+)-ATPase inhibitor) attenuated ERK 1/2 phosphorylation or cell proliferation. Osmotic pressure or chloride had no effect on Ang II-induced proliferative changes. High-sodium level did not affect Ang II receptor expression. Ang II increased intracellular pH via NHE-1 activation, and high-sodium level augmented the pH increase induced by Ang II. These data suggest that high-sodium level directly augments Ang II-induced VSMC proliferation through NHE-1- and ERK 1/2-dependent pathways and may offer new insights into the mechanisms of vascular remodeling by high-sodium/Ang II.
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Affiliation(s)
- Gang Liu
- 1] Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan [2] Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Hirofumi Hitomi
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Asadur Rahman
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Daisuke Nakano
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hirohito Mori
- Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Tsutomu Masaki
- Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hong Ma
- Department of Anesthesiology, First Affiliated Hospital of China Medical University, Shenyang, China
| | - Takahiro Iwamoto
- Department of Pharmacology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Hiroyuki Kobori
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Kagawa, Japan
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12
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Madamanchi NR, Runge MS. Redox signaling in cardiovascular health and disease. Free Radic Biol Med 2013; 61:473-501. [PMID: 23583330 PMCID: PMC3883979 DOI: 10.1016/j.freeradbiomed.2013.04.001] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 03/05/2013] [Accepted: 04/02/2013] [Indexed: 02/07/2023]
Abstract
Spatiotemporal regulation of the activity of a vast array of intracellular proteins and signaling pathways by reactive oxygen species (ROS) governs normal cardiovascular function. However, data from experimental and animal studies strongly support that dysregulated redox signaling, resulting from hyperactivation of various cellular oxidases or mitochondrial dysfunction, is integral to the pathogenesis and progression of cardiovascular disease (CVD). In this review, we address how redox signaling modulates the protein function, the various sources of increased oxidative stress in CVD, and the labyrinth of redox-sensitive molecular mechanisms involved in the development of atherosclerosis, hypertension, cardiac hypertrophy and heart failure, and ischemia-reperfusion injury. Advances in redox biology and pharmacology for inhibiting ROS production in specific cell types and subcellular organelles combined with the development of nanotechnology-based new in vivo imaging systems and targeted drug delivery mechanisms may enable fine-tuning of redox signaling for the treatment and prevention of CVD.
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Affiliation(s)
- Nageswara R Madamanchi
- McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Marschall S Runge
- McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Impact of high salt independent of blood pressure on PRMT/ADMA/DDAH pathway in the aorta of Dahl salt-sensitive rats. Int J Mol Sci 2013; 14:8062-72. [PMID: 23584024 PMCID: PMC3645731 DOI: 10.3390/ijms14048062] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 12/24/2022] Open
Abstract
Endothelial dysfunction participates in the development and progression of salt-sensitive hypertension. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase (NOS). The objectives of this study were to investigate the impact of a high salt diet on the PRMT/ADMA/DDAH (protein arginine methyltransferases; dimethylarginine dimethylaminohydrolase) pathway in Dahl salt-sensitive (DS) rats and SS-13BN consomic (DR) rats, and to explore the mechanisms that regulate ADMA metabolism independent of blood pressure reduction. Plasma levels of nitric oxide (NO) in DS rats given a high salt diet and subjected to intragastric administration of hydralazine (SH + HYD group) were lower than those given a normal salt diet (SN group). There were significant decreases in expression and activity of dimethylarginine dimethylaminohydrolase (DDAH) and endothelial NO synthase (eNOS) in DS rats given a high diet (SH group) in comparison to the SN group. The activity of DDAH and expression of eNOS in the SH + HYD group decreased more significantly than SN group. The mRNA expression of DDAH-1 and DDAH-2 were lowest in the SH group. The results suggest that salt, independent of blood pressure, can affect the PRMT-1/ADMA/DDAH system to a certain degree and lead to endothelial dysfunction in Dahl salt-sensitive rats.
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Angiostatin production increases in response to decreased nitric oxide in aging rat kidney. J Transl Med 2013; 93:334-43. [PMID: 23295649 DOI: 10.1038/labinvest.2012.171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The development of interstitial fibrosis occurs with aging. Impaired angiogenesis, associated with progressive loss of the renal microvasculature, is thought to be a cause of age-related nephropathy. However, the mechanism of capillary loss in aging kidney has not been fully elucidated. Angiostatin is a kringle-containing fragment of plasminogen and is a potent inhibitor of angiogenesis in vivo. Whether angiostatin generation is increased in the aging kidney has not been investigated. We examined 4, 10, 16, and 24-month-old Sprague-Dawley rats for angiostatin production and found that angiostatin generation was increased in aged rats. The protein expression and the activity of cathepsin D-the enzyme for angiostatin production--were increased in aged rats. In the aging kidney, nitric oxide (NO) availability is decreased. To investigate the role of NO in angiostatin production, human umbilical vein endothelial cells were treated with L-NG-nitroarginine methyl ester (L-NAME). L-NAME-treated cells showed increased cathepsin D activity and angiostatin production. For in vivo experiments, 16- to 18-month-old rats were treated with L-NAME or molsidomine for 3 months. Angiostatin production was increased in L-NAME-treated kidney, accompanied by increased cathepsin D activity. In contrast, angiostatin production was decreased in molsidomine-treated kidney, accompanied by decreased cathepsin D activity. In conclusion, angiostatin generation by cathepsin D was increased in the aging rat kidney. Decreased NO production activated cathepsin D activity. Increased angiostatin production may be related to capillary loss and interstitial damage in the aging rat kidney.
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Potthoff SA, Sitek B, Stegbauer J, Schulenborg T, Marcus K, Quack I, Rump LC, Meyer HE, Stühler K, Vonend O. The glomerular proteome in a model of chronic kidney disease. Proteomics Clin Appl 2012; 2:1127-39. [PMID: 21136910 DOI: 10.1002/prca.200800010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Adequate kidney function is crucial in sustaining vertebrate homeostasis. Certain diseases can diminish renal function and lead to end-stage renal disease. Diabetes mellitus and hypertension are the main causes of glomerulosclerosis and albuminuria in adults. The molecular mechanisms that trigger these maladaptive changes are still unsatisfyingly described. We previously introduced 2-D DIGE in combination with focused tissue isolation methods to analyze protein expression in glomeruli. Glomeruli, the crucial compartments in albuminuric renal diseases, were extracted using magnetic particles from subtotally nephrectomized FVB mice (n = 6); this 5/6 nephrectomy in FVB mice is a model of chronic kidney disease. Analysis of protein expression levels from glomerular protein lysates was performed using 2-D DIGE and compared with glomerular protein lysates from mice that underwent sham surgery. The comparison of about 2100 detectable spots between both groups revealed 48 protein spots that showed significant differential expression. Of those, 33 proteins could be identified using nanoLC-ESI MS. The metalloproteinase meprin 1 alpha, the beta galactoside-binding-lectin galectin-1 and dimethylarginine dimethylaminohydrolase 1, a key enzyme in NO metabolism, were found to be differentially regulated, thus implying a role in the pathogenesis and pathophysiology of progressive kidney disease. In conclusion, 2-D DIGE protein analysis of smallest sample sizes from specific organ compartments provides focused protein expression results, which help in gaining an understanding of the molecular mechanisms of chronic kidney disease.
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Affiliation(s)
- Sebastian A Potthoff
- Marienhospital Herne, Klinikum der Ruhr-Universität Bochum, Bochum, Germany; Department of Pathology, Vanderbilt University, Nashville, USA
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Lai YL, Aoyama S, Ohata M, Otsuka N, Shiokawa H, Tomono S, Fujiwara Y, Kanazawa H, Miyoshi N, Ohshima H. Dysregulation of dimethylargininedimethylaminohydrolase/asymmetric dimethylarginine pathway in rat type II diabetic nephropathy. J Clin Biochem Nutr 2012; 51:143-9. [PMID: 22962534 PMCID: PMC3432826 DOI: 10.3164/jcbn.11-33] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 01/25/2012] [Indexed: 11/22/2022] Open
Abstract
An impaired generation of nitric oxide has been associated with diabetic renal disease. In order to elucidate the underlying molecular mechanisms into how nitric oxide synthesis is impaired in diabetic renal disease, we examined changes in activities and expressions of some renal enzymes involved in nitric oxide production during the development of diabetic nephropathy in type II diabetic Otsuka Long-Evans Tokushima Fatty rats. Ten-week old Otsuka Long-Evans Tokushima Fatty (n = 40) and control Long-Evans Tokushima Otsuka rats (n = 20) were given drinking water containing 20% sucrose to accelerate the development of diabetic nephropathy. Otsuka Long-Evans Tokushima Fatty rats developed diabetic nephropathy in an age-dependent manner. Renal nitric oxide synthase activities in Otsuka Long-Evans Tokushima Fatty rats gradually declined with the progression of diabetic mellitus and were significantly lower than those of age-matched Long-Evans Tokushima Otsuka rats after 22 weeks of age. The lower activities of renal nitric oxide synthase in Otsuka Long-Evans Tokushima Fatty rats were correlated with relatively higher levels of renal free asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, and were also correlated with decreased activities of dimethylargininedimethylaminohydrolase which metabolizes asymmetric dimethylarginine to citrulline. These results imply that dimethylargininedimethylaminohydrolase dysregulation may play an important role in the development of diabetic nephropathy by increasing asymmetric dimethylarginine levels, which leads to inhibition of renal nitric oxide synthesis.
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Affiliation(s)
- Ying-Ling Lai
- Laboratory of Biochemistry and Global Center of Excellence Program, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
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17
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Yamaleyeva LM, Lindsey SH, Varagic J, Zhang LL, Gallagher PE, Chen AF, Chappell MC. Amelioration of renal injury and oxidative stress by the nNOS inhibitor L-VNIO in the salt-sensitive mRen2.Lewis congenic rat. J Cardiovasc Pharmacol 2012; 59:529-38. [PMID: 22370956 PMCID: PMC3369010 DOI: 10.1097/fjc.0b013e31824dd15b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Salt sensitivity is a key risk factor for cardiovascular disease and renal injury. Alterations in renal nitric oxide may contribute to salt-dependent increases in blood pressure and tissue damage. Therefore, we assessed the expression of nitric oxide synthase (NOS) isoforms in the kidney and the effects of nNOS inhibition on renal injury, inflammation, and oxidative stress in the female mRen2.Lewis rat (mRen), a model of salt-sensitive hypertension. We find that a high-salt diet (4% sodium) significantly reduced endothelial NOS mRNA (2.6-fold) and protein (1.5-fold) but increased nNOS mRNA (2.4-fold) and protein (1.9-fold) in the renal cortex of these animals. Immunostaining for nNOS also seemed higher in macula densa and cortical tubules of the rats fed a high-salt diet. Circulating nitrate and nitrite levels were reduced, including the tissue levels of the NOS cofactor tetrahydrobiopterin. Cortical markers of oxidative stress (4HNE, 8-OH-deoxyguanosine) and fibrosis were increased; however, mRNA levels of the NAD(P)H oxidase components NOX4, p22phox, and p47phox were reduced. Chronic treatment with the nNOS inhibitor N-(1-Imino-3-butenyl)-L-ornithine did not influence systolic blood pressure after 4 weeks but significantly attenuated albuminuria, renal fibrosis, inflammation, and indices of oxidative stress. We conclude that an increase in nNOS expression in conjunction with reduced levels of cortical tetrahydrobiopterin may stimulate oxidative stress and renal injury in the salt-sensitive female mRen2.Lewis rat.
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Affiliation(s)
- Liliya M Yamaleyeva
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1095, USA.
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18
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Wilcox CS. Asymmetric dimethylarginine and reactive oxygen species: unwelcome twin visitors to the cardiovascular and kidney disease tables. Hypertension 2012; 59:375-81. [PMID: 22215715 DOI: 10.1161/hypertensionaha.111.187310] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Plasma levels of asymmetric dimethylarginine or markers of reactive oxygen species are increased in subjects with risk factors for cardiovascular disease or chronic kidney disease. We tested the hypothesis that reactive oxygen species generate cellular asymmetric dimethylarginine that together cause endothelial dysfunction that underlies the risk of subsequent disease. Rat preglomerular vascular smooth muscle cells transfected with p22(phox) had increased NADPH oxidase activity, enhanced activity and expression of protein arginine methyltransferase, and reduced activity and protein expression of dimethylarginine dimethylaminotransferase and of cationic amino acid transferase 1 resulting in increased cellular levels of asymmetric dimethylarginine. Rats infused with angiotensin II had oxidative stress. The endothelial function of their mesenteric arterioles was changed from vasodilatation to vasoconstriction, accompanied by increased vascular asymmetric dimethylarginine. All of these changes were prevented by Tempol. In vivo silencing of dimethylarginine dimethylaminotransferase 1 increased plasma levels of asymmetric dimethylarginine, whereas silencing of dimethylarginine dimethylaminotransferase 2 impaired endothelial function. We suggest that initiation factors, such as angiotensin II, expressed in blood vessels or tissues of subjects with cardiovascular and kidney disease risk factors generate reactive oxygen species from NADPH oxidase that enhances cellular asymmetric dimethylarginine in an amplification loop. This leads to adverse changes in vascular and organ functions, as a consequence of reduced tissue levels of NO and increased reactive oxygen species. Thus, we conclude that reactive oxygen species and asymmetric dimethylarginine form a tightly coupled amplification system that translates cardiovascular/kidney risk into overt disease.
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Affiliation(s)
- Christopher S Wilcox
- Division of Nephrology and Hypertension, Georgetown University Medical Center, 3800 Reservoir Rd, NW, 6 PHC Building, F6003, Washington, DC 20007, USA.
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Abstract
Excess daily salt intake impairs vasodilatation and enhances vasoconstriction, resulting in reduction of regional blood flow and elevation of blood pressure in healthy individuals and hypertensive patients with either salt sensitivity or not tested for salt sensitivity or not evaluated for salt sensitivity. The mechanism may involve decreased production of nitric oxide via endothelial nitric oxide synthase (eNOS), impaired bioavailability of nitric oxide, and elevated plasma levels of asymmetric dimethylarginine (ADMA). Experimental animals, irrespective of salt sensitivity, although less extensive in those with salt-resistance, fed a high-salt diet have deteriorated endothelial functions; the mechanisms involved include an impairment of eNOS activation, a decrease in eNOS expression, and an increase in oxidative stress and ADMA. The imbalance of interactions between nitric oxide and angiotensin II is also involved in salt sensitivity. Deficiency of nitric oxide formed via neuronal NOS and inducible NOS may contribute to salt-induced hypertension. Reduced daily salt intake, therefore, would be the most rational prophylactic measure against the development of hypertension.
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Nakamura T, Sato E, Fujiwara N, Kawagoe Y, Takeuchi M, Maeda S, Yamagishi SI. Atorvastatin reduces proteinuria in non-diabetic chronic kidney disease patients partly via lowering serum levels of advanced glycation end products (AGEs). OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:304-7. [PMID: 21150335 PMCID: PMC3154036 DOI: 10.4161/oxim.3.5.13069] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
There is accumulating evidence that advanced glycation end products (AGEs) play a role in the development and progression of chronic kidney disease (CKD). We have previously found that atorvastatin treatment significantly reduces serum levels of AGEs in type 2 diabetic patients and subjects with non-alcoholic steatohepatitis in a cholesterol loweringindependent manner. In this study, we examined whether atorvastatin could reduce proteinuria partly via reduction of serum levels of AGEs in non-diabetic CKD patients. Ten non-diabetic normotensive stage I or II CKD patients with dyslipidemia were enrolled. Patients were treated with atorvastatin (10 mg/day) for one year. All subjects underwent determination of blood chemistries, proteinuria and serum levels of AGEs at baseline and after one year. Atorvastatin treatment for one year significantly decreased circulating levels of total cholesterol, LDL cholesterol, triglycerides and AGEs, while it increased HDL cholesterol levels. Further, although atorvastatin treatment did not affect estimated glomerular filtration rate, it significantly reduced proteinuria. In univariate analyses, proteinuria levels were correlated with total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol (inversely) and AGEs. Multiple stepwise regression analysis revealed that AGE level was a sole independent correlate of proteinuria. In this initial examination of the patients in this study, our present study suggests that atorvastatin could decrease proteinuria in non-diabetic CKD patients with dyslipidemia partly via reduction of serum levels of AGEs. Atorvastatin may have AGE-lowering effects in CKD patients as well that could contribute to renoprotective properties of this agent.
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Affiliation(s)
- Tsukasa Nakamura
- Division of Nephrology, Department of Internal Medicine, Shinmatsudo Central General Hospital, Chiba, Japan
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21
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Lu D, Fu Y, Lopez-Ruiz A, Zhang R, Juncos R, Liu H, Manning RD, Juncos LA, Liu R. Salt-sensitive splice variant of nNOS expressed in the macula densa cells. Am J Physiol Renal Physiol 2010; 298:F1465-71. [PMID: 20335319 DOI: 10.1152/ajprenal.00650.2009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuronal nitric oxide synthase (nNOS), which is abundantly expressed in the macula densa cells, attenuates tubuloglomerular feedback (TGF). We hypothesize that splice variants of nNOS are expressed in the macula densa, and nNOS-beta is a salt-sensitive isoform that modulates TGF. Sprague-Dawley rats received a low-, normal-, or high-salt diet for 10 days and levels of the nNOS-alpha, nNOS-beta, and nNOS-gamma were measured in the macula densa cells isolated with laser capture microdissection. Three splice variants of nNOS, alpha-, beta-, and gamma-mRNAs, were detected in the macula densa cells. After 10 days of high-salt intake, nNOS-alpha decreased markedly, whereas nNOS-beta increased two- to threefold in the macula densa measured with real-time PCR and in the renal cortex measured with Western blot. NO production in the macula densa was measured in the perfused thick ascending limb with an intact macula densa plaque with a fluorescent dye DAF-FM. When the tubular perfusate was switched from 10 to 80 mM NaCl, a maneuver to induce TGF, NO production by the macula densa was increased by 38 +/- 3% in normal-salt rats and 52 +/- 6% (P < 0.05) in the high-salt group. We found 1) macula densa cells express nNOS-alpha, nNOS-beta, and nNOS-gamma, 2) a high-salt diet enhances nNOS-beta, and 3) TGF-induced NO generation from macula densa is enhanced in high-salt diet possibly from nNOS-beta. In conclusion, we found that the splice variants of nNOS expressed in macula densa cells were alpha-, beta-, and gamma-isoforms and propose that enhanced level of nNOS-beta during high-salt intake may contribute to macula densa NO production and help attenuate TGF.
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Affiliation(s)
- Deyin Lu
- Department of Physiology and Biophysics, Division of Nephrology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA
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22
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Subramani J, Leo MDM, Kathirvel K, Arunadevi R, Singh TU, Prakash VR, Mishra SK. Essential role of nitric oxide in sepsis-induced impairment of endothelium-derived hyperpolarizing factor-mediated relaxation in rat pulmonary artery. Eur J Pharmacol 2009; 630:84-91. [PMID: 20035746 DOI: 10.1016/j.ejphar.2009.12.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 12/01/2009] [Accepted: 12/15/2009] [Indexed: 10/20/2022]
Abstract
Both endothelial nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) are important vasodilators in pulmonary circulation. Sepsis is known to impair endothelium-dependent dilation in the pulmonary vasculature, but the mechanisms are incompletely understood. We have examined the relative contribution of EDHF/NO to the attenuated endothelium-dependent relaxation of pulmonary artery in sepsis, and the role of inducible nitric oxide synthase (iNOS)-derived NO in this mechanism. Sepsis was induced in male adult Wistar rats by caecal ligation and puncture. At 18h after surgery, left and right branches of pulmonary arteries were isolated for tension recording, NO/cyclic guanosine monophosphate (cGMP) measurements, mRNA and protein expressions. Despite a marked decrease in the arterial endothelial nitric oxide synthase (eNOS) mRNA and phosphorylated-eNOS (p-eNOS) protein expressions in sepsis, endothelium-dependent relaxation to acetylcholine (ACh) mediated by NO, acetylcholine-stimulated NO release and tissue cGMP levels were moderately inhibited. Sepsis however abolished the N(G)-Nitro-l-arginine methyl ester (L-NAME)/indomethacin-resistant arterial relaxation (EDHF response) to acetylcholine in this vessel. In vitro treatment of the arterial rings from septic rats with 1400W, a selective inhibitor of iNOS restored the EDHF response, but had no effect on the acetylcholine-induced relaxation mediated by endothelial NO. The functional role of iNOS-derived NO in impairing EDHF-mediated relaxation was coincident with an increased basal NO production, iNOS mRNA and protein expressions in the rat pulmonary artery. In conclusion, the loss of the EDHF response may be primarily responsible for the endothelial dysfunction in sepsis, and its restoration by a selective iNOS inhibitor may improve pulmonary vasodilation.
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Affiliation(s)
- Jaganathan Subramani
- Division of Pharmacology and Toxicology, Indian Veterinary Research Institute, Izatnagar-243 122 (U.P), India
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Ezetimibe decreases serum levels of asymmetric dimethylarginine (ADMA) and ameliorates renal injury in non-diabetic chronic kidney disease patients in a cholesterol-independent manner. Pharmacol Res 2009; 60:525-8. [DOI: 10.1016/j.phrs.2009.04.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 04/15/2009] [Accepted: 04/15/2009] [Indexed: 12/15/2022]
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Bergmann IP, Böger RH, Marti E, Frey FJ, Schwedhelm E, Eisenberger U. Renal Resistance Index in Renal Allograft Recipients: A Role for ADMA. Am J Kidney Dis 2009; 54:327-33. [DOI: 10.1053/j.ajkd.2009.04.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 04/29/2009] [Indexed: 11/11/2022]
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Hultström M, Helle F, Iversen BM. AT1 receptor activation regulates the mRNA expression of CAT1, CAT2, arginase-1, and DDAH2 in preglomerular vessels from angiotensin II hypertensive rats. Am J Physiol Renal Physiol 2009; 297:F163-8. [DOI: 10.1152/ajprenal.00087.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Previously, we found increased expression of l-arginine metabolizing enzymes in both kidneys from two-kidney, one-clip (2K1C) hypertensive rats (Helle F, Hultstrom M, Skogstrand T, Palm F, Iversen BM. Am J Physiol Renal Physiol 296: F78–F86, 2009). In the present study, we investigate whether AT1 receptor activation can induce the changes observed in 2K1C. Four groups of rats were infused with 80 ng/min ANG II or saline for 14 days and/or given 60 mg·kg−1·day−1 losartan. Gene expression was studied in isolated preglomerular vessels by RT-PCR. Dose-responses to ANG II were studied in isolated preglomerular vessels with and without acute NOS inhibition [10−4 mol/l NG-nitro-l-arginine methyl ester (l-NAME)]. Expressions of endothelial nitric oxide synthase (eNOS), caveolin-1, and arginase-2 were not changed by ANG II infusion. CAT1 (0.3 8 ± 0.07 to 0.73 ± 0.12, P < 0.05), CAT2 (1.14 ± 0.29 to 2.74 ± 0.48), DDAH2 (1.09 ± 0.27 to 2.3 ± 0.46), and arginase-1 (1.08 ± 0.17 to 1.82 ± 0.22) were increased in ANG II-infused rats. This was prevented by losartan treatment, which reduced the expression of eNOS (0.97 ± 0.26 to 0.37 ± 0.11 in controls; 0.8 ± 0.16 to 0.36 ± 0.1 in ANG II-infused rats) and caveolin-1 (2.49 ± 0.59 to 0.82 ± 0.24 in controls and 2.59 ± 0.61 to 1.1 ± 0.25 in ANG II-infused rats). ANG II (10−10 mol/l) caused vessels from ANG II-infused animals to contract to 53 ± 15% of baseline diameter and 90 ± 5% of baseline diameter in controls ( P < 0.05) and was further enhanced by l-NAME to 4 ± 4% of baseline diameter ( P < 0.05). In vivo losartan treatment reduced the reactivity of isolated vessels to 91 ± 2% of baseline in response to 10−7 mol/l ANG II compared with 82 ± 3% in controls ( P < 0.05) and prevented the increased responsiveness caused by ANG II infusion. In conclusion, CAT1, CAT2, DDAH2, and arginase-1 expression in renal resistance vessels is regulated through the AT1 receptor. This finding may be of direct importance for NOS and the regulation of preglomerular vascular function.
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Banday AA, Lokhandwala MF. Inhibition of natriuretic factors increases blood pressure in rats. Am J Physiol Renal Physiol 2009; 297:F397-402. [PMID: 19474184 DOI: 10.1152/ajprenal.90729.2008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Renal dopamine and nitric oxide contribute to natriuresis during high-salt intake which maintains sodium and blood pressure homeostasis. We wanted to determine whether concurrent inhibition of these natriuretic factors increases blood pressure during high-sodium intake. Male Sprague-Dawley rats were divided into the following groups: 1) vehicle (V)-tap water, 2) NaCl-1% NaCl drinking water, 3) 30 mM l-buthionine sulfoximine (BSO), an oxidant, 4) BSO plus NaCl, and 5) BSO plus NaCl with 1 mM tempol (antioxidant). Compared with V, NaCl intake for 10 days doubled sodium intake and increased urinary dopamine level but reduced urinary nitric oxide content. NaCl intake also reduced basal renal proximal tubular Na-K-ATPase activity with no effect on blood pressure. However, NaCl intake in BSO-treated rats failed to reduce basal Na-K-ATPase activity despite higher urinary dopamine levels. Also, dopamine failed to inhibit proximal tubular Na-K-ATPase activity and these rats exhibited reduced urinary nitric oxide levels and high blood pressure. Tempol supplementation in NaCl plus BSO-treated rats reduced blood pressure. BSO treatment alone did not affect the urinary nitric oxide and dopamine levels or blood pressure. However, dopamine failed to inhibit proximal tubular Na-K-ATPase activity in BSO-treated rats. BSO treatment also increased basal protein kinase C activity, D1 receptor serine phosphorylation, and oxidative markers like malondialdehyde and 8-isoprostane. We suggest that NaCl-mediated reduction in nitric oxide does not increase blood pressure due to activation of D1 receptor signaling. Conversely, oxidative stress-provoked inhibition of D1 receptor signaling fails to elevate blood pressure due to presence of normal nitric oxide. However, simultaneously decreasing nitric oxide levels with NaCl and inhibiting D1 receptor signaling with BSO elevated blood pressure.
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Affiliation(s)
- Anees Ahmad Banday
- Heart and Kidney Institute, College of Pharmacy, Univ. of Houston, 4800 Calhoun Road, Houston, TX 77204, USA.
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Kawada H, Yasuoka Y, Fukuda H, Kawahara K. Low [NaCl]-induced neuronal nitric oxide synthase (nNOS) expression and NO generation are regulated by intracellular pH in a mouse macula densa cell line (NE-MD). J Physiol Sci 2009; 59:165-73. [PMID: 19340543 PMCID: PMC10716943 DOI: 10.1007/s12576-009-0022-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Accepted: 01/14/2009] [Indexed: 10/20/2022]
Abstract
Changes in the luminal NaCl concentration ([NaCl]) at the macula densa (MD) modulate the tubuloglomerular feedback (TGF) responses via an affect on the release of nitric oxide (NO). This study was performed in a newly established mouse macula densa cell line (NE-MD) to investigate the effects of lowering [NaCl] on the neuronal NO synthase (nNOS) protein expression and L-arginine (Arg)-induced NO release. Expression of nNOS protein and release of NO were evaluated by Western blot analysis and an NO-sensitive electrode, respectively. Intracellular pH (pH(i)) was monitored by the BCECF assay. Although there was weak staining of the nNOS protein expression, L-Arg-induced NO generation was negligible in normal (140 mM NaCl) solution. Both were significantly (P < 0.05) increased either in the presence of furosemide (12 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter, or in a low (23 mM) Cl(-) solution. Furosemide- and low Cl(-)-induced NO generation was completely inhibited by 50 microM 7-nitroindasole (7-NI), a nNOS inhibitor. Moreover, these increases were significantly (P < 0.05) inhibited by the addition of 100 microM amiloride, an inhibitor of the Na(+)/H(+) exchanger, or by its analogue 5-(N)-ethyl-N-isopropyl amiloride (EIPA), and also at a lower pH of 7.1. Furthermore, nNOS expression and NO release were not stimulated in as low as 19 mM Na(+) solution. In conclusion, low [Cl(-)], but not low [Na(+)] in the lumen at the MD, increased nNOS protein expression and NO generation. Changes in the luminal [NaCl] may modulate the TGF system via an effect on the NO generation from the MD.
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Affiliation(s)
- Hideaki Kawada
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
| | - Yukiko Yasuoka
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
| | - Hidekazu Fukuda
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
| | - Katsumasa Kawahara
- Department of Cellular and Molecular Physiology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
- Department of Physiology, Kitasato University School of Medicine, Kitasato 1-15-1, Sagamihara, 228-8555 Japan
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Cacanyiova S, Kristek F, Gerova M, Krenek P, Klimas J. Effect of chronic nNOS inhibition on blood pressure, vasoactivity, and arterial wall structure in Wistar rats. Nitric Oxide 2009; 20:304-10. [PMID: 19303939 DOI: 10.1016/j.niox.2009.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 03/04/2009] [Accepted: 03/13/2009] [Indexed: 11/26/2022]
Abstract
While the unequivocal pattern of endothelial nitric oxide (NO) synthase (eNOS) inhibition in cardiovascular control has been recognised, the role of NO produced by neuronal NOS (nNOS) remains unclear. The purpose of the present study was to describe the cardiovascular effects of NO production interference by inhibition of nNOS with 7-nitroindazole (7-NI). Wistar rats (10 weeks old) were used: control and experimental rats were administered 7-NI 10 mg/kg b.w./day in drinking water for 6 weeks. Systolic blood pressure (BP) was measured by the tail-cuff plethysmographic method. Isolated thoracic aortas (TAs) were used to study vasomotor activity of the conduit artery in vitro. The BP response of anaesthetised animals was used to follow the cardiovascular-integrated response in vivo. Geometry of the TA was measured after perfusion fixation (120 mm Hg) by light microscopy. Expression of eNOS was measured in the TA by immunoblot analysis. Although 6 weeks of nNOS inhibition did not alter systolic BP, the heart/body weight ratio was decreased. Relaxation of the TA in response to acetylcholine (10(-9)-10(-5)mol/L) was moderately inhibited. However, no difference in the BP hypotensive response after acetylcholine (0.1, 1, 10 microg) was observed. The contraction of TA in response to noradrenaline (10(-10)-10(-5)mol/L), and the BP pressor response to noradrenaline (0.1, 1 microg) was attenuated. The inner diameter of the TA was increased, and the wall thickness, wall cross-sectional area, and wall thickness/inner diameter ratio were decreased. The expression of eNOS in the TA was increased. In summary, cardiac and TA wall hypotrophy, underlined by decreased contractile efficiency, were observed. The results suggested that two constitutive forms of NOS (nNOS, eNOS) likely participate in regulation of cardiovascular tone by different mechanisms.
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Affiliation(s)
- Sona Cacanyiova
- Institute of Normal and Pathological Physiology, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, Sienkiewiczova 1, 813 71 Bratislava, Slovak Republic
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Friederich M, Nordquist L, Olerud J, Johansson M, Hansell P, Palm F. Identification and distribution of uncoupling protein isoforms in the normal and diabetic rat kidney. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 645:205-12. [PMID: 19227473 DOI: 10.1007/978-0-387-85998-9_32] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Uncoupling protein (UCP)-2 and -3 are ubiquitously expressed throughout the body but there is currently no information regarding the expression and distribution of the different UCP isoforms in the kidney. Due to the known cross-reactivity of the antibodies presently available for detection of UCP-2 and -3 proteins, we measured the mRNA expression of UCP-1, -2 and -3 in the rat kidney in order to detect the kidney-specific UCP isoforms. Thereafter, we determined the intrarenal distribution of the detected UCP isoforms using immunohistochemistry. Thereafter, we compared the protein levels in control and streptozotocin-induced diabetic rats using Western blot. Expressions of the UCP isoforms were also performed in brown adipose tissue and heart as positive controls for UCP-1 and 3, respectively. UCP-2 mRNA was the only isoform detected in the kidney. UCP-2 protein expression in the kidney cortex was localized to proximal tubular cells, but not glomerulus or distal nephron. In the medulla, UCP-2 was localized to cells of the medullary thick ascending loop of Henle, but not to the vasculature or parts of the nephron located in the inner medulla. Western blot showed that diabetic kidneys have about 2.5-fold higher UCP-2 levels compared to controls. In conclusion, UCP-2 is the only isoform detectable in the kidney and UCP-2 protein can be detected in proximal tubular cells and cells of the medullary thick ascending loop of Henle. Furthermore, diabetic rats have increased UCP-2 levels compared to controls, but the mechanisms underlying this increase and its consequences warrants further studies.
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Affiliation(s)
- Malou Friederich
- Department of Medical Cell Biology, BMC, PO 571, Uppsala University, 751 23 Uppsala, Sweden
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Friederich M, Fasching A, Hansell P, Nordquist L, Palm F. Diabetes-induced up-regulation of uncoupling protein-2 results in increased mitochondrial uncoupling in kidney proximal tubular cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:935-40. [PMID: 18439413 DOI: 10.1016/j.bbabio.2008.03.030] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/19/2008] [Accepted: 03/27/2008] [Indexed: 11/28/2022]
Abstract
We have previously reported increased O(2) consumption unrelated to active transport by tubular cells and up-regulated mitochondrial uncoupling protein (UCP)-2 expressions in diabetic kidneys. It is presently unknown if the increased UCP-2 levels in the diabetic kidney results in mitochondrial uncoupling and increased O(2) consumption, which we therefore investigated in this study. The presence of UCP-2 in proximal tubular cells was confirmed by immunohistochemistry and found to be increased (western blot) in homogenized tissue and isolated mitochondria from kidney cortex of diabetic rats. Isolated proximal tubular cells had increased total and ouabain-insensitive O(2) consumption compared to controls. Isolated mitochondria from diabetic animals displayed increased glutamate-stimulated O(2) consumption (in the absence of ADP and during inhibition of the ATP-synthase by oligomycin) compared to controls. Guanosine diphosphate, an UCP inhibitor, and bovine serum albumin which removes fatty acids that are essential for UCP-2 uncoupling activity, independently prevented the increased glutamate-stimulated O(2) consumption in mitochondria from diabetic animals. In conclusion, diabetic rats have increased mitochondrial UCP-2 expression in renal proximal tubular cells, which results in mitochondrial uncoupling and increased O(2) consumption. This mechanism may be protective against diabetes-induced oxidative stress, but will increase O(2) usage. The subsequently reduced O(2) availability may contribute to diabetes-induced progressive kidney damage.
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Affiliation(s)
- Malou Friederich
- Department of Medical Cell Biology, Division of Integrative Physiology, Uppsala University, Uppsala, Sweden
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Wang D, Strandgaard S, Borresen ML, Luo Z, Connors SG, Yan Q, Wilcox CS. Asymmetric dimethylarginine and lipid peroxidation products in early autosomal dominant polycystic kidney disease. Am J Kidney Dis 2008; 51:184-91. [PMID: 18215696 DOI: 10.1053/j.ajkd.2007.09.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 09/27/2007] [Indexed: 12/22/2022]
Abstract
BACKGROUND Patients with autosomal dominant polycystic kidney disease (ADPKD) with normal renal function have endothelial dysfunction and decreased nitric oxide synthase activity in subcutaneous resistance vessels. We investigated asymmetric dimethylarginine (ADMA) as a marker of an inhibitor of nitric oxide synthase and the lipid peroxidation product 13-hydroxyoctadecadienoic acid (HODE) as a marker of oxidative stress in patients with early ADPKD. STUDY DESIGN Cross-sectional study. SETTING & PARTICIPANTS Patients with early ADPKD (n = 27) and age-matched volunteers (n = 30) from a single academic medical center. FACTOR Patients with ADPKD versus controls. OUTCOMES & MEASUREMENT Plasma (P) levels, urinary (U) excretion, and urinary clearance (C) of ADMA and HODE. Because of multiple comparisons, P for significance is considered less than 0.0167. RESULTS Patients with ADPKD had significantly increased P(ADMA) levels (604 +/- 131 versus 391 +/- 67 nmol/L; P < 0.01) and U(ADMA) excretion (22 +/- 4 versus 15.2 +/- 3 nmol/micromol creatinine; P = 0.01), decreased C(ADMA) (25 +/- 3 versus 33 +/- 4 mL/min; P = 0.01), increased P(HODE) levels (316 +/- 64 versus 230 +/- 38 nmol/L; P < 0.01) and U(HODE) excretion (467 +/- 67 versus 316 +/- 40 nmol/micromol creatinine; P < 0.01), and decreased plasma nitrite plus nitrate (P(NOx)) levels (21 +/- 5 versus 32 +/- 6 micromol/L; P < 0.01) and U(NOx) excretion (59 +/- 7 versus 138 +/- 27 micromol/micromol creatinine; P < 0.01). LIMITATIONS Small sample size, cross-sectional nature of study, and limited number of markers of oxidative stress. CONCLUSIONS P(ADMA) and P(HODE) levels are increased in patients with early ADPKD. Increased P(ADMA) level is related to decreased C(ADMA) and is accompanied by oxidative stress.
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Affiliation(s)
- Dan Wang
- Cardiovascular-Kidney-Hypertension Institute, Division of Nephrology and Hypertension and Angiogenesis Section, Lombardi Cancer Institute, Georgetown University, Washington, DC 20007, USA.
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Onozato ML, Tojo A, Leiper J, Fujita T, Palm F, Wilcox CS. Expression of NG,NG-dimethylarginine dimethylaminohydrolase and protein arginine N-methyltransferase isoforms in diabetic rat kidney: effects of angiotensin II receptor blockers. Diabetes 2008; 57:172-80. [PMID: 17909098 DOI: 10.2337/db06-1772] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) is generated by protein arginine N-methyltransferase (PRMT)-1 and is metabolized by N(G),N(G)-dimethylarginine dimethylaminohydrolase (DDAH). We tested the hypothesis that increased serum ADMA (S(ADMA)) in the streptozotocin (STZ)-induced diabetic rat model of diabetes is mediated by an angiotensin receptor blocker-sensitive change in DDAH or PRMT expression. RESEARCH DESIGN AND METHODS Data were compared from four groups of rats: sham-injected controls, untreated STZ-induced diabetic rats at 4 weeks, STZ-induced diabetic rats administered the angiotensin II (Ang II) receptor blocker telmisartan for 2 weeks, and control rats administered telmisartan for 2 weeks. RESULTS Immunostaining and Western blotting of microdissected nephron segments localized DDAH I in the proximal tubules and DDAH II in the glomeruli, afferent arterioles, macula densa, and distal nephron. Renal Ang II and S(ADMA) increased with diabetes but were normalized by 2 weeks of telmisartan. DDAH I expression was decreased in diabetic kidneys, while DDAH II expression was increased. These changes were reversed by telmisartan, which also reduced expression of PRMT-1 and -5. Telmisartan increased expressions of DDAH I but decreased DDAH II in Ang II-stimulated kidney slices ex vivo. CONCLUSIONS Renal Ang II and S(ADMA) are increased in insulinopenic diabetes. They are normalized by an Ang II receptor blocker, which increases the renal expression of DDAH I, decreases PRMT-1, and increases renal NO metabolites.
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Jacobi J, Maas R, Cordasic N, Koch K, Schmieder RE, Böger RH, Hilgers KF. Role of asymmetric dimethylarginine for angiotensin II-induced target organ damage in mice. Am J Physiol Heart Circ Physiol 2007; 294:H1058-66. [PMID: 18156199 DOI: 10.1152/ajpheart.01103.2007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to investigate the role of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) and its degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH) in angiotensin II (ANG II)-induced hypertension and target organ damage in mice. Mice transgenic for the human DDAH1 gene (TG) and wild-type (WT) mice (each, n = 28) were treated with 1.0 microg kg(-1) min(-1) ANG II, 3.0 microg kg(-1) min(-1) ANG II, or phosphate-buffered saline over 4 wk via osmotic minipumps. Blood pressure, as measured by tail cuff, was elevated to the same degree in TG and WT mice. Plasma levels of ADMA were lower in TG than WT mice and were not affected after 4 wk by either dose of ANG II in both TG and WT animals. Oxidative stress within the wall of the aorta, measured by fluorescence microscopy using the dye dihydroethidium, was significantly reduced in TG mice. ANG II-induced glomerulosclerosis was similar between WT and TG mice, whereas renal interstitial fibrosis was significantly reduced in TG compared with WT animals. Renal mRNA expression of protein arginine methyltransferase (PRMT)1 and DDAH2 increased during the infusion of ANG II, whereas PRMT3 and endogenous mouse DDAH1 expression remained unaltered. Chronic infusion of ANG II in mice has no effect on the plasma levels of ADMA after 4 wk. However, an overexpression of DDAH1 alleviates ANG II-induced renal interstitial fibrosis and vascular oxidative stress, suggesting a blood pressure-independent effect of ADMA on ANG II-induced target organ damage.
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Affiliation(s)
- Johannes Jacobi
- Department of Nephrology and Hypertension, Friedrich Alexander University Erlangen-Nuremberg, Erlangen, Germany
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Palm F, Onozato ML, Luo Z, Wilcox CS. Dimethylarginine dimethylaminohydrolase (DDAH): expression, regulation, and function in the cardiovascular and renal systems. Am J Physiol Heart Circ Physiol 2007; 293:H3227-45. [PMID: 17933965 DOI: 10.1152/ajpheart.00998.2007] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Asymmetric (N(G),N(G))-dimethylarginine (ADMA) inhibits nitric oxide (NO) synthases (NOS). ADMA is a risk factor for endothelial dysfunction, cardiovascular mortality, and progression of chronic kidney disease. Two isoforms of dimethylarginine dimethylaminohydrolase (DDAH) metabolize ADMA. DDAH-1 is the predominant isoform in the proximal tubules of the kidney and in the liver. These organs extract ADMA from the circulation. DDAH-2 is the predominant isoform in the vasculature, where it is found in endothelial cells adjacent to the cell membrane and in intracellular vesicles and in vascular smooth muscle cells among the myofibrils and the nuclear envelope. In vivo gene silencing of DDAH-1 in the rat and DDAH +/- mice both have increased circulating ADMA, whereas gene silencing of DDAH-2 reduces vascular NO generation and endothelium-derived relaxation factor responses. DDAH-2 also is expressed in the kidney in the macula densa and distal nephron. Angiotensin type 1 receptor activation in kidneys reduces the expression of DDAH-1 but increases the expression of DDAH-2. This rapidly evolving evidence of isoform-specific distribution and regulation of DDAH expression in the kidney and blood vessels provides potential mechanisms for nephron site-specific regulation of NO production. In this review, the recent advances in the regulation and function of DDAH enzymes, their roles in the regulation of NO generation, and their possible contribution to endothelial dysfunction in patients with cardiovascular and kidney diseases are discussed.
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Affiliation(s)
- Fredrik Palm
- Division of Nephrology and Hypertension, Georgetown University, 3800 Reservoir Road N.W., Washington, DC 20007, USA
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Abstract
In the kidney nitric oxide (NO) has numerous important functions including the regulation of renal haemodynamics, maintenance of medullary perfusion, mediation of pressure-natriuresis, blunting of tubuloglomerular feedback, inhibition of tubular sodium reabsorption and modulation of renal sympathetic neural activity. The net effect of NO in the kidney is to promote natriuresis and diuresis. Significantly, deficient renal NO synthesis has been implicated in the pathogenesis of hypertension. All three isoforms of nitric oxide synthase (NOS), namely neuronal NOS (nNOS or NOS1), inducible NOS (iNOS or NOS2) and endothelial NOS (eNOS or NOS3) are reported to contribute to NO synthesis in the kidney. The regulation of NO synthesis in the kidney by NOSs is complex and incompletely understood. Historically, many studies of NOS regulation in the kidney have emphasized the role of variations in gene transcription and translation. It is increasingly appreciated, however, that the constitutive NOS isoforms (nNOS and eNOS) are also subject to rapid regulation by post-translational mechanisms such as Ca(2+) flux, serine/threonine phosphorylation and protein-protein interactions. Recent studies have emphasized the role of post-translational regulation of nNOS and eNOS in the regulation of NO synthesis in the kidney. In particular, a role for phosphorylation of nNOS and eNOS at both activating and inhibitory sites is emerging in the regulation of NO synthesis in the kidney. This review summarizes the roles of NO in renal physiology and discusses recent advances in the regulation of eNOS and nNOS in the kidney by post-translational mechanisms such as serine/threonine phosphorylation.
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Affiliation(s)
- P F Mount
- The Austin Research Institute, Austin Hospital, Victoria, Australia.
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Cheng HF, Zhang MZ, Harris RC. Nitric oxide stimulates cyclooxygenase-2 in cultured cTAL cells through a p38-dependent pathway. Am J Physiol Renal Physiol 2006; 290:F1391-7. [PMID: 16380459 DOI: 10.1152/ajprenal.00315.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
To examine the interaction of nitric oxide (NO) and cyclooxygenase (COX-2) and the signaling pathway involved, primary cultured rabbit cortical thick ascending limb (cTAL) were used. In these cells, immunoreactive COX-2 and vasodilatory prostaglandins were increased by a NO donor, S-nitros- N-acetylpenicillamine (SNAP; 2.5 ± 0.3-fold control, n = 6, P < 0.01). SNAP increased expression of phosphorylated p38 (pp38; 2.4 ± 0.3-fold control; n = 5; P < 0.01), which was inhibited by the p38 inhibitor SB-203580 (1.3 ± 0.1-fold control, n = 5, P < 0.01). SB-203580 inhibited SNAP-induced COX-2 expression [1.4 ± 0.2-fold control, n = 6, not significant (NS) vs. control] and levels of PGE2significantly. In cTAL cells transfected with a luciferase reporter driven by the wild-type mouse COX-2 promoter, SNAP stimulated luciferase activity, which was reversed by SB-203580 (control vs. SNAP vs. SNAP + SB-203580: 1.4 ± 0.2-, 8.3 ± 1.4-, and 0.4 ± 0.1-fold control, respectively, n = 4, P < 0.01). Electrophoretic mobility shift assay indicated that SNAP stimulated nuclear factor (NF)-κB binding activity in cTAL that was also inhibited by the p38 inhibitor. SNAP was not able to stimulate a mutant COX-2 promoter construct that is not activated by NF-κB (0.9 ± 0.1, 1.2 ± 0.1, and 1.0 ± 0.2 respectively, n = 4, NS). Low chloride increased COX-2 expression (2.7 ± 0.4-fold control, n = 6, P < 0.01) and pp38 expression (2.8 ± 0.3-fold; n = 5, P < 0.01), which were reversed by the specific NO synthase (NOS) inhibitor 7-nitroindazole. Administration of a low-salt diet increased immunoreactive COX-2 and neuronal NOS (nNOS) in the macula densa and surrounding cTAL of kidneys of wild-type mice but did not significantly elevate COX-2 expression in nNOS−/−mice. In summary, these studies indicate that, in cTAL, NO can increase COX-2 expression in cTAL and macula densa through p38-dependent signaling pathways via activation of NF-κB.
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Affiliation(s)
- Hui-Fang Cheng
- George M. O'Brien Kidney and Urologic Diseases Center and Division of Nephrology, Vanderbilt Univ. School of Medicine, and Nashville Veterans Affairs Hospital, Nashville, TN 37232, USA
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Tojo A, Onozato ML, Fujita T. Role of macula densa neuronal nitric oxide synthase in renal diseases. Med Mol Morphol 2006; 39:2-7. [PMID: 16575507 DOI: 10.1007/s00795-006-0310-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 01/13/2006] [Indexed: 10/24/2022]
Abstract
Macula densa cells have an important role in the regulation of glomerular blood flow and glomerular filtration by its regulation of afferent arteriolar vascular tone. Nitric oxide derived from neuronal nitric oxide synthase (nNOS) in macula densa can dilate afferent arterioles. Macula densa nNOS is important for renin secretion, and its expression is regulated by dietary salt, renal angiotensin II, intracellular pH, and other factors. In salt-sensitive hypertension, nNOS is suppressed, whereas in SHR or in the early phase of diabetes, nNOS is increased in macula densa along with NADPH oxidase, which limits NO bioavailability. Renal damage induced by hypertension, diabetes, and hyperlipidemia could be prevented by enhancement of nNOS in macula densa with ACEI, dipyridamole, alpha(1)-receptor blocker, a low-salt diet, or sodium bicarbonate. Sodium bicarbonate is a safe and clinically available enhancer of nNOS in macula densa that increases glomerular blood flow and prevents the reduction of GFR in radiocontrast nephropathy and chronic renal failure. In conclusion, the enhancement of nNOS in the macula densa can be a promising strategy to prevent reduction of renal function.
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Affiliation(s)
- Akihiro Tojo
- Division of Nephrology and Endocrinology, University of Tokyo, Bunkyo-ku, Japan.
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Wang D, Chabrashvili T, Borrego L, Aslam S, Umans JG. Angiotensin II infusion alters vascular function in mouse resistance vessels: roles of O and endothelium. J Vasc Res 2005; 43:109-19. [PMID: 16340215 DOI: 10.1159/000089969] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Accepted: 09/01/2005] [Indexed: 11/19/2022] Open
Abstract
We hypothesized that prolonged angiotensin II (AngII) infusion would alter vascular reactivity by enhancing superoxide anion (O-.2) generation. Male C57BL/6 mice were infused with AngII at 400 ng/kg/min (n=16, AngII mice) or vehicle (n=16, sham mice) for 2 weeks via subcutaneous osmotic minipumps. Contraction and relaxation of mesenteric resistance vessels (MRVs) were assessed using a Mulvany-Halpern myograph. AngII infusion increased systolic blood pressure, MRV NADPH oxidase activity and expression of p22phox mRNA. Contraction to norepinephrine was unchanged, but AngII infusion increased contractile responses to AngII (41+/-5 vs. 10+/-4%, p<0.001) and endothelin-1 (ET-1; 95+/-10 vs. 70+/-9%, p<0.05), which was normalized by tempol (10(-4) M, a stable membrane-permeable superoxide dismutase mimetic) and ebselen [10(-5) M, a peroxynitrite (ONOO-) scavenger]. Endothelium removal enhanced MRV contraction to AngII and ET-1 in sham mice but blunted these contractile responses in AngII mice. Relaxation to ACh was impaired in AngII mice (60.1+/-8.8 vs. 83.2+/-3.5%, p<0.01), which normalized by tempol, whereas relaxation to sodium nitroprusside was similar in both groups. N-nitro-L-arginine (NNLA, a nitric oxide synthase inhibitor), partially inhibited acetylcholine relaxation of vessels from sham mice but not from AngII mice. The residual endothelium-dependent hyperpolarizing-factor-like relaxation was not different between groups. In conclusion,the AngII slow pressor response in mouse MRVs consisted of specific contractile hyperresponsiveness and impairment in the NO-mediated component of endothelium-dependent relaxation, which was mediated by O-.2 and ONOO- in the vascular smooth muscle cell.
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Affiliation(s)
- Dan Wang
- Division of Nephrology and Hypertension, Department of Medicine, Georgetown University, Washington, DC 20007, USA.
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Wilcox CS. Oxidative stress and nitric oxide deficiency in the kidney: a critical link to hypertension? Am J Physiol Regul Integr Comp Physiol 2005; 289:R913-35. [PMID: 16183628 DOI: 10.1152/ajpregu.00250.2005] [Citation(s) in RCA: 357] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is growing evidence that oxidative stress contributes to hypertension. Oxidative stress can precede the development of hypertension. In almost all models of hypertension, there is oxidative stress that, if corrected, lowers BP, whereas creation of oxidative stress in normal animals can cause hypertension. There is overexpression of the p22(phox) and Nox-1 components of NADPH oxidase and reduced expression of extracellular superoxide dismutase (EC-SOD) in the kidneys of ANG II-infused rodents, whereas there is overexpression of p47(phox) and gp91(phox) and reduced expression of intracellular SOD with salt loading. Several mechanisms have been identified that can make oxidative stress self-sustaining. Reactive oxygen species (ROS) can enhance afferent arteriolar tone and reactivity both indirectly via potentiation of tubuloglomerular feedback and directly by microvascular mechanisms that diminish endothelium-derived relaxation factor/nitric oxide responses, generate a cyclooxygenase-2-dependent endothelial-derived contracting factor that activates thromboxane-prostanoid receptors, and enhance vascular smooth muscle cells reactivity. ROS can diminish the efficiency with which the kidney uses O(2) for Na(+) transport and thereby diminish the P(O(2)) within the kidney cortex. This may place a break on further ROS generation yet could further enhance vasculopathy and hypertension. There is a tight relationship between oxidative stress in the kidney and the development and maintenance of hypertension.
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Affiliation(s)
- Christopher S Wilcox
- Division of Nephrology and Hypertension, Georgetown University Medical Center, 3800 Reservoir Rd., NW, Washington, DC 20007, USA.
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Mount PF, Fraser SA, Watanabe Y, Lane N, Katsis F, Chen ZP, Kemp BE, Power DA. Phosphorylation of neuronal and endothelial nitric oxide synthase in the kidney with high and low salt diets. Nephron Clin Pract 2005; 102:p36-50. [PMID: 16244499 DOI: 10.1159/000089092] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Accepted: 07/04/2005] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Renal nitric oxide (NO) synthesis increases with increasing salt intake, however, the mechanisms underlying this are poorly understood. We hypothesized that activating or inhibitory phosphorylation of neuronal and endothelial nitric oxide synthase (nNOS, eNOS) regulates renal NO production in response to altered dietary salt. METHODS Sprague-Dawley rats were fed low, normal or high salt diets for 12 h or 2 weeks, and kidney NOS phosphorylation was analyzed by Western blot using phosphopeptide antibodies against the sites nNOS-Ser(1412), nNOS-Ser(847), eNOS-Ser(1176) and eNOS-Thr(494). RESULTS At 12 h, total nNOS increased 1.4-fold (p < 0.01) in the high salt group and decreased by 26% (p < 0.05) in the low salt group. Changes in expression of phospho-nNOS at 12 h were accounted for by the changes in total nNOS. No change in total or phospho-eNOS was seen at 12 h. At 2 weeks, in the low salt group expression of total nNOS increased 1.8-fold (p < 0.05) whereas expression of nNOS phosphorylated at the inhibitory site Ser(847) increased 4.3-fold (p < 0.01). Total eNOS was increased 3-fold in the low salt group (p < 0.01), with parallel increases in eNOS phosphorylated at both activating and inhibitory sites (p < 0.05). In the 2-week high salt group no changes in NOS expression or phosphorylation were seen, despite the observed increased excretion of urinary NO metabolites. CONCLUSION In summary, changes in phospho-nNOS and phospho-eNOS expression occurred in parallel with changes in total expression, thus, the overall activating and inhibitory effects of nNOS and eNOS phosphorylation at the sites studied were not changed by altered dietary salt.
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Affiliation(s)
- Peter F Mount
- The Austin Research Institute, Austin Hospital, Heidelberg, Australia.
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Asaba K, Tojo A, Onozato ML, Goto A, Quinn MT, Fujita T, Wilcox CS. Effects of NADPH oxidase inhibitor in diabetic nephropathy. Kidney Int 2005; 67:1890-8. [PMID: 15840036 DOI: 10.1111/j.1523-1755.2005.00287.x] [Citation(s) in RCA: 240] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND We used apocynin to test the hypothesis that superoxide anion (O(-) (2)) from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase underlies the development of diabetic nephropathy in the rat. METHODS Rats received apocynin (16 mg/kg/day) from 2 to 8 weeks after inducing diabetes mellitus (DM) with streptozotocin. RESULTS DM increased excretion of hydrogen peroxide (H(2)O(2)), lipid peroxidation products (LPO), nitric oxide products (NOx), and protein. The kidneys of rats with DM had increased expression of p47phox and gp91phox and endothelial nitric oxide synthase (eNOS), and increased mesangial matrix with expression of fibronectin and collagen I. Apocynin prevented the increase in excretion of H(2)O(2), LPO, and protein in diabetic rats, increased renal NOx generation, and prevented the increased renal expression of gp91phox and the membrane fraction of p47phox, and reverted the mesangial matrix expansion. CONCLUSION Activation of NADPH oxidase with translocation of p47phox to the membrane underlies the oxidative stress and limited NO generation, despite enhanced eNOS expression in a model of diabetic nephropathy. Apocynin prevents these changes and the associated proteinuria.
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Affiliation(s)
- Kensuke Asaba
- Division of Nephrology and Endocrinology, University of Tokyo, Tokyo, Japan
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Tojo A, Onozato ML, Kobayashi N, Goto A, Matsuoka H, Fujita T. Antioxidative effect of p38 mitogen-activated protein kinase inhibitor in the kidney of hypertensive rat. J Hypertens 2005; 23:165-74. [PMID: 15643139 DOI: 10.1097/00004872-200501000-00027] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase is regulated by angiotensin II, interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha via p38 mitogen-activated protein kinase (MAPK). We hypothesized that p38 MAPK inhibitor, FR167653, may suppress NAD(P)H oxidase and its oxygen radical production and ameliorate renal damage in Dahl salt-sensitive rats with heart failure (DSHF). METHODS DSHF rats were fed with 8% NaCl diet from 6 to 18 weeks old. Eleven-week-old DSHF rats received either vehicle or FR167653 (2 mg/kg per day) for 7 weeks and the renal NAD(P)H oxidase p47phox and nitric oxide synthase (NOS), superoxide production and renal damage were evaluated in comparison with the control Dahl salt-resistant rat fed with 8% NaCl diet. RESULTS In the kidney of DSHF rat, phosphorylated p38 MAPK was enhanced with an increased IL-1beta and TNF-alpha production compared with control rats. Treatment with FR167653 significantly suppressed p38 MAPK, IL-1beta and TNF-alpha. Renal NAD(P)H oxidase p47phox expression and superoxide production were significantly increased in the DSHF rats and treatment with FR167653 suppressed NAD(P)H oxidase expression and reduced superoxide formation. Renal endothelial and inducible NOS were reduced in DSHF rats compared with control rats, but FR167653 increased NOS and NO production in the kidney. Proteinuria, glomerulosclerosis and interstitial macrophage migration via intercellular adhesion molecule-1 (ICAM-1) were enhanced in DSHF rat and they were ameliorated by FR167653. CONCLUSION The inhibition of p38 MAPK by FR167653 reduced renal IL-1beta and TNF-alpha production and ameliorated renal damage in hypertensive rat via suppression of NAD(P)H oxidase and enhanced NO bioavailability.
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Affiliation(s)
- Akihiro Tojo
- Division of Nephrology and Endocrinology, University of Tokyo, Tokyo, Japan.
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Yasuoka Y, Kawada H, Suzuki Y, Sato M, Endou H, Obinata M, Kawahara K. Establishment of a Mouse Macula Densa Cell Line with an nNOS Promoter Driving EGFP Expression. ACTA ACUST UNITED AC 2005; 55:365-72. [PMID: 16412259 DOI: 10.2170/jjphysiol.r2138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 01/04/2006] [Indexed: 11/05/2022]
Abstract
We describe a unique method for establishing a functionally intact macula densa cell line from immortalized renal cells in culture. The macula densa is involved in the tubuloglomerular feedback (TGF) system in the kidney and specifically expresses neuronal nitric oxide synthase (nNOS). A 347 bp portion of the nNOS promoter was used to drive the expression of enhanced green fluorescence protein (EGFP). An immortalized distal tubule (DT) cell line was derived from distal tubules microdissected from the kidneys of SV40 large T antigen transgenic mice. Immunofluorescence labeling using an antibody against nNOS revealed no specific EGFP expression in immunofluorescence-negative DT cells. The established cell line (NE-MD) showed a time-dependent increase in signals of the nNOS protein when they were incubated with 12 microM furosemide (an inhibitor of Na(+)-K(+)-2Cl(-) symporter) for 5 h. In conclusion, this newly developed macula densa cell line will be useful in studies of the TGF stem.
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Affiliation(s)
- Yukiko Yasuoka
- Department of Physiology, Kitasato University School of Medicine, Sagamihara 228-8555, Japan
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Okubo K, Hayashi K, Wakino S, Matsuda H, Kubota E, Honda M, Tokuyama H, Yamamoto T, Kajiya F, Saruta T. Role of Asymmetrical Dimethylarginine in Renal Microvascular Endothelial Dysfunction in Chronic Renal Failure with Hypertension. Hypertens Res 2005; 28:181-9. [PMID: 16025746 DOI: 10.1291/hypres.28.181] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We examined whether endothelial function of the renal microcirculation was impaired in a model of chronic renal failure (CRF), and further assessed the role of asymmetrical dimethylarginine (ADMA) and its degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH), in mediating the deranged nitric oxide (NO) synthesis in CRF. CRF was established in male mongrel dogs by subtotal nephrectomy, and the animals were used in experiments after a period of 4 weeks. The endothelial function of the renal afferent and efferent arterioles was evaluated according to the response to acetylcholine, using an intravital needle-lens charge-coupled device camera. Intrarenal arterial infusion of acetylcholine (0.01 microg/kg/min) elicited 22+/-2% and 20+/-2% dilation of the afferent and efferent arterioles in normal dogs. In dogs with CRF, this vasodilation was attenuated (afferent, 12+/-2%; efferent, 11+/-1%), and the attenuation paralleled the diminished increments in urinary nitrite+nitrate excretion. In the animals with CRF, plasma concentrations of homocysteine (12.2+/-0.7 vs. 6.8+/-0.4 micromol/l) and ADMA were elevated (2.60+/-0.13 vs. 1.50+/-0.08 micromol/l). The inhibition of S-adenosylmethionine-dependent protein arginine N-methyltransferase by adenosine dialdehyde decreased plasma ADMA levels, and improved the acetylcholine-induced changes in urinary nitrite+nitrate excretion and arteriolar vasodilation. Acute methionine loading impaired the acetylcholine-induced renal arteriolar vasodilation in CRF, but not normal dogs, and the impairment in CRF dogs coincided with the changes in plasma ADMA levels. Real-time polymerase chain reaction revealed downregulation of the mRNA expression of DDAH-II in the dogs with CRF. Collectively, these results provide direct in vivo evidence of endothelial dysfunction in canine CRF kidneys. The endothelial dysfunction was attributed to the inhibition of the NO production by elevated ADMA, which involved the downregulation of DDAH-II. The deranged NO metabolic pathway including ADMA and DDAH is a novel mechanism for the aggravation of renal function.
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Affiliation(s)
- Ken Okubo
- Department of Internal Medicine, School of Medicine, Keio University. Tokyo, Japan. ; *Department of Urology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Abstract
Cellular injury or organ dysfunction from oxidative stress occurs when reactive oxygen species (ROS) accumulate in excess of the host defense mechanisms. The deleterious effect of ROS occurs from 2 principal actions. First, ROS can inactivate mitochondrial enzymes, damage DNA, or lead to apoptosis or cellular hypertrophy. Second, nitric oxide (NO), which is a principal endothelial-derived relaxing factor, reacts with superoxide anion (O2-) to yield peroxynitrite (ONOO-), which is a powerful oxidant and nitrosating agent. The inactivation of NO by O2- creates NO deficiency. Oxidative stress can promote the production of vasoconstrictor molecules and primary salt retention by the kidney. Several hypertensive animal models showed increased activity of nicotine adenine dinucleotide phosphate (NADPH) oxidase, which is the chief source of O2- in the vessel wall and kidneys. NO regulates renal blood flow, tubuloglomerular feedback (TGF), and pressure natriuresis. Animal models of NO deficiency develop hypertension, proteinuria, and glomerulosclerosis. Evidence is presented that chronic renal failure (CRF) is a state of NO deficiency secondary to decreased kidney NO production and/or increased bioinactivation of NO by O2-. Patients with CRF show decreased endothelium-dependent vasodilatation to acetylcholine, have increased markers of oxidative stress, and diminished antioxidant activity. Therapy for oxidative stress has focused on antioxidants and agents that modify the renin-angiotensin system. The effects of such treatments are more compelling in animal models than in human studies.
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Affiliation(s)
- Paul S Modlinger
- Division of Nephrology and Hypertension, Georgetown University Medical Center, Washington, DC 20007, USA
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Paliege A, Mizel D, Medina C, Pasumarthy A, Huang YG, Bachmann S, Briggs JP, Schnermann JB, Yang T. Inhibition of nNOS expression in the macula densa by COX-2-derived prostaglandin E2. Am J Physiol Renal Physiol 2004; 287:F152-9. [PMID: 15010356 DOI: 10.1152/ajprenal.00287.2003] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
It is well established that cyclooxygenase-2 (COX-2) and the neuronal form of nitric oxide synthase (nNOS) are coexpressed in macula densa cells and that the expression of both enzymes is stimulated in a number of high-renin states. To further explore the role of nNOS and COX-2 in renin secretion, we determined plasma renin activity in mice deficient in nNOS or COX-2. Plasma renin activity was significantly reduced in nNOS −/− mice on a mixed genetic background and in COX-2 −/− mice on either BALB/c or C57/BL6 congenic backgrounds. In additional studies, we accumulated evidence to show an inhibitory influence of PGE2on nNOS expression. In a cultured macula densa cell line, PGE2significantly reduced nNOS mRNA expression, as quantified by real-time RT-PCR. In COX-2 −/− mice, nNOS mRNA expression in the kidney, determined by real-time RT-PCR, was upregulated throughout the postnatal periods, ranging from postnatal day ( PND) 3 to PND 60. The induction of nNOS protein expression and NOS activity in COX-2 −/− mice was localized to macula densa cells using immunohistochemistry and NADPH-diaphorase staining methods, respectively. Therefore, these findings reveal that the absence of either COX-2 or nNOS is associated with suppressed renin secretion. Furthermore, the inhibitory effect of PGE2on nNOS mRNA expression indicates a novel interaction between NO and prostaglandin-mediated pathways of renin regulation.
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Affiliation(s)
- Alex Paliege
- National Institute of Diabetes and Kidney Disease, National Institutes of Health, Bethesda, MD 20892, USA
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Suliman HB, Ali M, Piantadosi CA. Superoxide dismutase-3 promotes full expression of the EPO response to hypoxia. Blood 2004; 104:43-50. [PMID: 15016652 DOI: 10.1182/blood-2003-07-2240] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractExtracellular superoxide dismutase (SOD3) is the primary extracellular enzymatic scavenger of superoxide (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(^{{\cdot}}\mathrm{O}_{2}^{-}\) \end{document}). SOD3's expression is highest in the kidney, but its distribution and biologic functions there are unknown. To investigate the function of renal SOD3, we colocalized it with erythropoietin (EPO) to proximal tubules using in situ hybridization and immunohistochemistry. We then exposed wild-type (Wt) and SOD3 knock-out (KO) mice to hypoxia and found a late hematocrit response in the KO strain. EPO mRNA expression was attenuated in KO mice during the first 6 hours of hypoxia preceded at 2 hours by less accumulation of nuclear hypoxia-inducible transcription factor 1 α (HIF-1α) protein. Meanwhile KO mice exposed to hypoxia showed increases in renal mRNA for superoxide-producing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX4) and early significant increases in glutathione disulfide (GSSG)/glutathione (GSH), a marker of oxidative stress, compared with Wt mice. Plasma nitrite/nitrate and renal 3-nitrotyrosine (3-NTyr), indicating peroxynitrite formation, increased later in hypoxia, and renal endothelial nitric oxide synthase protein induction was similar in both strains. These data show that hypoxic activation of HIF-1α and its target gene EPO in mouse kidney is regulated closely by the oxidant/antioxidant equilibrium involving SOD3, thus identifying renal SOD3 as a regulatory element in the body's innate adaptation to hypoxia.
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Affiliation(s)
- Hagir B Suliman
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
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Khosla UM, Johnson RJ. Hypertension in the hemodialysis patient and the "lag phenomenon": insights into pathophysiology and clinical management. Am J Kidney Dis 2004; 43:739-51. [PMID: 15042553 DOI: 10.1053/j.ajkd.2003.12.036] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Mukundan H, Resta TC, Kanagy NL. 17-β Estradiol Independently Regulates Erythropoietin Synthesis and NOS Activity during Hypoxia. J Cardiovasc Pharmacol 2004; 43:312-7. [PMID: 14716223 DOI: 10.1097/00005344-200402000-00023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We reported previously that 17-beta estradiol (E2-beta) attenuates hypoxic induction of erythropoietin (EPO) synthesis in rats. We hypothesized this attenuation is mediated by increased nitric oxide (NO) bio-availability. To investigate this hypothesis, ovariectomized estrogen-depleted rats were instrumented with arterial and venous catheters and treated with either E2-beta (20 microg/24 hrs) or vehicle (polypropylene glycol) for 7 days. Rats were placed in Plexiglas boxes and administered a bolus of either the NO synthase inhibitor, Nomega-nitro-L-arginine (l-NNA, 15 mg/kg) or saline. Following this bolus, saline or l-NNA was continuously infused (15 mg/kg/h) throughout the 8 hours of hypoxic exposure (12% O2). Hypoxia increased plasma NO metabolites (NOx) in both saline groups but more in E2-beta-treated rats. l-NNA prevented this increase in both groups. Renal endothelial NO synthase (NOS) expression was unaltered by hypoxia, l-NNA, or E2-beta. Despite preventing increases in plasma NOx during hypoxia, l-NNA did not affect E2-beta attenuation of EPO synthesis. We conclude that E2-beta independently attenuates hypoxic induction of EPO and augments hypoxic increases in NO synthesis.
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Affiliation(s)
- Harshini Mukundan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico, Health Sciences Center Albuquerque, New Mexico 87131, USA
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Wang D, Chen Y, Chabrashvili T, Aslam S, Borrego Conde LJ, Umans JG, Wilcox CS. Role of Oxidative Stress in Endothelial Dysfunction and Enhanced Responses to Angiotensin II of Afferent Arterioles from Rabbits Infused with Angiotensin II. J Am Soc Nephrol 2003; 14:2783-9. [PMID: 14569088 DOI: 10.1097/01.asn.0000090747.59919.d2] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
ABSTRACT. The hypothesis that O2·− enhances angiotensin II (AngII)-induced vasoconstriction and impairs acetylcholine-induced vasodilation of afferent arterioles (Aff) in AngII–induced hypertension was investigated. Rabbits (n = 6 per group) received 12 to 14 d of 0.154 M NaCl (Sham), subpressor AngII (60 ng/kg per min; AngII 60) or slow pressor AngII (200 ng/kg per min; AngII 200). Individual Aff were perfused in vitro at 60 mmHg. AngII 200 increased mean arterial pressure (mean ± SD; 103 ± 9 versus 73 ± 6 mmHg; P < 0.01), plasma lipid peroxides (2.6 ± 0.3 versus 2.0 ± 0.3 nM; P < 0.05), renal cortical NADPH- and NADH-dependent O2·− generation, and Aff mRNA for p22phox 5-fold (P < 0.001) but decreased that for AT1-receptor 2.4-fold (P < 0.01). AngII 60 increased only NADH-dependent O2·− generation by renal cortex. Aff from AngII 200 rabbits had diminished acetylcholine relaxations (+50 ± 4 versus +85 ± 6%; P < 0.001), but these became similar in the presence of nitro-l-arginine (10−4 M). Aff from AngII 60 and AngII 200 rabbits had unchanged norepinephrine contractions (10−7 M) but significantly (P < 0.05) enhanced AngII contractions (10−8 M: Sham −52 ± 5 versus AngII 60 to 77 ± 5 versus AngII 200 to 110 ± 10%). The superoxide dismutase mimetic tempol (10−4 M) moderated the AngII responses of Aff from AngII 200 rabbits to levels of AngII 60 rabbits (−64 ± 7%). The AngII slow pressor response enhances renal cortical O2·− and p22phox expression. Increased O2·− generation in Aff mediates an impaired nitric oxide synthase–dependent endothelium-derived relaxing factor response and paradoxically enhances contractions to AngII despite downregulation of the mRNA for AT1 receptors. A subpressor dose of AngII enhances Aff responses to AngII independent of O2·−. E-mail: wilcoxch@georgetown.edu
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Affiliation(s)
- Dan Wang
- Division of Nephrology and Hypertension and Center for Hypertension and Renal Disease Research, Georgetown University, Washington, DC 20007, USA
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