David L Mattson

Medical College of Wisconsin, Milwaukee, Wisconsin, United States

Are you David L Mattson?

Claim your profile

Publications (95)414.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Research studying the role of inflammation in hypertension and cardiovascular disease has flourished in recent years; however, the exact mechanisms by which the activated immune cells lead to the development and maintenance of hypertension remain to be elucidated. The objectives of this brief review are to summarize and discuss the most recent findings in the field, with special emphasis on potential therapeutics to treat or prevent hypertension. This review will cover novel immune cell subtypes recently associated to the disease including the novel role of cytokines, toll-like receptors, and inflammasomes in hypertension.
    Current Hypertension Reports 01/2015; 17(1):507. · 3.90 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Environmental exposure of parents or early in life may affect disease development in adults. We found that hypertension and renal injury induced by a high-salt diet were substantially attenuated in Dahl SS/JrHsdMcwiCrl (SS/Crl) rats that had been maintained for many generations on the grain-based 5L2F diet compared with SS/JrHsdMcwi rats (SS/Mcw) maintained on the casein-based AIN-76A diet (mean arterial pressure, 116±9 versus 154±25 mm Hg; urinary albumin excretion, 23±12 versus 170±80 mg/d). RNAseq analysis of the renal outer medulla identified 129 and 82 genes responding to a high-salt diet uniquely in SS/Mcw and SS/Crl rats, respectively, along with minor genetic differences between the SS substrains. The 129 genes responding to salt in the SS/Mcw strain included numerous genes with homologs associated with hypertension, cardiovascular disease, or renal disease in human. To narrow the critical window of exposure, we performed embryo-transfer experiments in which single-cell embryos from 1 colony (SS/Mcw or SS/Crl) were transferred to surrogate mothers from the other colony, with parents and surrogate mothers maintained on their respective original diet. All offspring were fed the AIN-76A diet after weaning. Salt-induced hypertension and renal injury were substantially exacerbated in rats developed from SS/Crl embryos transferred to SS/Mcw surrogate mothers. Conversely, salt-induced hypertension and renal injury were significantly attenuated in rats developed from SS/Mcw embryos transferred to SS/Crl surrogate mothers. Together, the data suggest that maternal diet during the gestational-lactational period has substantial effects on the development of salt-induced hypertension and renal injury in adult SS rats. © 2014 American Heart Association, Inc.
    Hypertension 12/2014; · 7.63 Impact Factor
  • 11th International Symposium on Resistance Arteries (ISRA)., Banff, AB, Canada.; 09/2014
  • David L Mattson
    [Show abstract] [Hide abstract]
    ABSTRACT: The importance of the immune system in hypertension, vascular disease, and renal disease has been appreciated for over 50 years. Recent experimental advances have led to a greater appreciation of the mechanisms whereby inflammation and immunity participate in cardiovascular disease. In addition to the experimental data, multiple studies in patients have demonstrated a strong correlation between the observations made in animals and humans. Of great interest is the development of salt-sensitive hypertension in humans with the concurrent increase in albumin excretion rate. Experiments in our laboratory have demonstrated that feeding a high NaCl diet to Dahl Salt-Sensitive (SS) rats results in a significant infiltration of T-lymphocytes into the kidney that is accompanied by the development of hypertension and renal disease. The development of disease in the Dahl SS closely resembles observations made in patients; studies were therefore performed to investigate the pathological role of infiltrating immune cells in the kidney in hypertension and renal disease. Pharmacological and genetic studies indicate that immune cell infiltration into the kidney amplifies the disease process. Further experiments demonstrated that infiltrating T cells may accentuate the Dahl SS phenotype by increasing intrarenal AngII and oxidative stress. From these and other data, we hypothesize that infiltrating immune cells, which surround the blood vessels and tubules, can serve as a local source of bioactive molecules which mediate vascular constriction, increase tubular sodium reabsorption, and mediate the retention of sodium and water to amplify sodium-sensitive hypertension. Multiple experiments remain to be performed to refine and clarify this hypothesis.
    American journal of physiology. Renal physiology 07/2014; · 3.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Small GTPase Ras-related protein 1 (Rap1b) controls several basic cellular phenomena, and its deletion in mice leads to several cardiovascular defects, including impaired adhesion of blood cells and defective angiogenesis. We found that Rap1b(-/-) mice develop cardiac hypertrophy and hypertension. Therefore, we examined the function of Rap1b in regulation of blood pressure. RAP1B: (-/-) mice developed cardiac hypertrophy and elevated blood pressure, but maintained a normal heart rate. Correcting elevated blood pressure with losartan, an angiotensin II type 1 receptor, alleviated cardiac hypertrophy in Rap1b(-/-) mice, suggesting a possibility that cardiac hypertrophy develops secondary to hypertension. The indices of renal function and plasma renin activity were normal in Rap1b(-/-) mice. Ex vivo, we examined whether the effect of Rap1b deletion on smooth muscle-mediated vessel contraction and endothelium-dependent vessel dilation, 2 major mechanisms controlling basal vascular tone, was the basis for the hypertension. We found increased contractility on stimulation with a thromboxane analog or angiotensin II or phenylephrine along with increased inhibitory phosphorylation of myosin phosphatase under basal conditions consistent with elevated basal tone and the observed hypertension. Cyclic adenosine monophosphate-dependent relaxation in response to Rap1 activator, Epac, was decreased in vessels from Rap1b(-/-) mice. Defective endothelial release of dilatory nitric oxide in response to elevated blood flow leads to hypertension. We found that nitric oxide-dependent vasodilation was significantly inhibited in Rap1b-deficient vessels. This is the first report to indicate that Rap1b in both smooth muscle and endothelium plays a key role in maintaining blood pressure by controlling normal vascular tone.
    Arteriosclerosis Thrombosis and Vascular Biology 05/2014; · 6.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies implicate infiltrating immune cells in the kidney in the pathogenesis of Dahl salt sensitive hypertension. SH2B3, an adaptor protein shown to participate in vascular and inflammatory signaling, is associated with hypertension in human GWAS (Nature Gen 41:667), though the mechanisms underlying the association are unclear. To address this issue, zinc finger nuclease targeting of the SH2 domain of SH2B3 was performed in the Dahl SS rat (SS/JrHsdMcwi) and resulted in an in-frame, 6 base pair deletion. Following salt stress, the SH2B3 mutants (SS-Sh2b3em1Mcwi) had significantly lower blood pressure (135 ± 1 mmHg vs 168 ± 8 mmHg, n=4-6/group) and attenuated kidney disease as indicated by albumin excretion rate (38 ± 7 mg/day vs 104 ± 9 mg/day) than the Dahl SS. Infiltration of leukocytes in the kidneys was significantly blunted in the SH2B3 mutant compared to the Dahl SS (5.4 ± 0.5 106/kidney vs 2.7 ± 0.3 106/kidney), and qPCR results show a significant reduction of IL-6 (2 fold) and MCP-1(1.8 fold) gene expression in the SH2B3 cortex. Vascular reactivity of mesenteric resistance arteries via wire myography in response serotonin or acetylcholine was not different between the SH2B3 mutant and Dahl SS. The mutation in SH2B3 appears to attenuate Dahl SS hypertension via inflammatory signaling and may reflect an underlying role for inflammation in human hypertension.
    The FASEB Journal 04/2014; 28(1):1136.15. · 5.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The CD3 ζ chain (CD247), a gene involved in T-cell signaling, has been shown to associate with blood pressure in human genetic studies. To test the functional role of CD247 in hypertension and renal disease, zinc-finger nucleases targeting CD247 were injected into Dahl salt-sensitive (SS/JrHsdMcwi) embryos. The resulting 11-bp frameshift deletion in exon 1 of CD247 led to a predicted premature stop codon. Western blotting confirmed the absence of CD247 protein in the thymus, and flow cytometry (n=5-9 per group) demonstrated that the mutant rats (CD247(-/-)) have a >99% reduction in circulating CD3(+) T cells compared with littermate controls (CD247(+/+)). Studies were performed on age-matched, littermate male, CD247(+/+) and CD247(-/-) rats fed a 4.0% NaCl diet for 3 weeks. The infiltration of CD3(+) T cells into the kidney after high salt was significantly blunted in CD247(-/-) (1.4±0.4×10(5) cells per kidney) when compared with that in the CD247(+/+) (8.7±2.0×10(5) cells per kidney). Accompanying the reduced infiltration of T cells, mean arterial blood pressure was significantly lower in CD247(-/-) than in CD247(+/+) (134±1 versus 151±2 mm Hg). As an index of kidney disease, urinary albumin and protein excretion rates were significantly reduced in CD247(-/-) (17±1 and 62±2 mg/d, respectively) when compared with that in CD247(+/+) (49±3 and 121±5 mg/d, respectively). Glomerular and renal tubular damage were also attenuated in the CD247(-/-). These studies demonstrate that functional T cells are required for the full development of Dahl salt-sensitive hypertension and indicate that the association between CD247 and hypertension in humans may be related to altered immune cell function.
    Hypertension 03/2014; 63(3):559-64. · 7.63 Impact Factor
  • Satarupa Das, David L Mattson
    [Show abstract] [Hide abstract]
    ABSTRACT: Administration of exogenous L-Arginine (L-Arg) attenuates Angiotensin II (AngII)-mediated hypertension and kidney disease in rats. The present study assessed renal hemodynamics and pressure-diuresis-natriuresis in anesthetized rats infused with vehicle, AngII (20 ng/kg/min, iv) or AngII + L-Arg (300 μg/kg/min, iv). Increasing renal perfusion pressure (RPP) from approximately 100 to 140 mmHg resulted in a 9-10 fold increase in urine flow and sodium excretion rate in control animals. In comparison, AngII infusion significantly reduced renal blood flow (RBF) and glomerular filtration rate (GFR) by 40-42% and blunted the pressure-dependent increase in urine flow and sodium excretion rate by 54-58% at elevated RPP. Supplementation of L-Arg reversed the vasoconstrictor effects of AngII and restored pressure-dependent diuresis to levels not significantly different from control rats.Experiments in isolated aortic rings were performed to assess L-Arg effects on the vasculature. Dose-dependent contraction to AngII (10(-10) M to 10(-7) M) was observed with a maximal force equal to 27±3% of the response to 10(-5) M phenylephrine. Contraction to 10(-7) M AngII was blunted by 75±3% with 10(-4) M L-Arg. The influence of L-Arg to blunt AngII mediated contraction was eliminated by endothelial denudation or incubation with nitric oxide synthase inhibitors. Moreover, the addition of 10(-3) M cationic or neutral amino acids, which compete with L-Arg for cellular uptake, blocked the effect of L-Arg. Anionic amino acids did not influence the effects of L-Arg on AngII-mediated contraction. These studies indicate that L-Arg blunts AngII-mediated vascular contraction by an endothelial- and NOS-dependent mechanism involving cellular uptake of L-Arg. This article is protected by copyright. All rights reserved.
    Clinical and Experimental Pharmacology and Physiology 01/2014; · 2.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Transient receptor potential vanilloid type 4 (TRPV4) is an endothelial Ca(2+) entry channel contributing to endothelium-mediated dilation in conduit and resistance arteries. We investigated the role of TRPV4 in the regulation of blood pressure and endothelial function under hypertensive conditions. TRPV4-deficient (TRPV4(-/-)) and wild-type (WT) control mice were given l-NAME (0.5 g/L) in drinking water for 7 days or subcutaneously infused with angiotensin (Ang) II (600 ng/kg per minute) for 14 days, and blood pressure measured by radiotelemetry. TRPV4(-/-) mice had a lower baseline mean arterial pressure (MAP) (12-h daytime MAP, 94 ± 2 vs. 99 ± 2 mmHg in WT controls). l-NAME treatment induced a slightly greater increase in MAP in TRPV4(-/-) mice (day 7, 13 ± 4%) compared to WT controls (6 ± 2%), but Ang II-induced increases in MAP were similar in TRPV4(-/-) and WT mice (day 14, 53 ± 6% and 37 ± 11%, respectively, P < 0.05). Chronic infusion of WT mice with Ang II reduced both acetylcholine (ACh)-induced dilation (dilation to 10(-5) mol/L ACh, 71 ± 5% vs. 92 ± 2% of controls) and the TRPV4 agonist GSK1016790A-induced dilation of small mesenteric arteries (10(-8) mol/L GSK1016790A, 14 ± 5% vs. 77 ± 7% of controls). However, Ang II treatment did not affect ACh dilation in TRPV4(-/-) mice. Mechanistically, Ang II did not significantly alter either TRPV4 total protein expression in mesenteric arteries or TRPV4 agonist-induced Ca(2+) response in mesenteric endothelial cells in situ. These results suggest that TRPV4 channels play a minor role in blood pressure regulation in l-NAME- but not Ang II-induced hypertension, but may be importantly involved in Ang II-induced endothelial dysfunction.
    Physiological reports. 01/2014; 2(1):e00199.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Multiple genes and pathways are involved in the pathogenesis of hypertension. Epigenomic studies of hypertension are beginning to emerge and hold great promise of providing novel insights into the mechanisms underlying hypertension. Epigenetic marks or mediators including DNA methylation, histone modifications, and noncoding RNA can be studied at a genome or near-genome scale using epigenomic approaches. At the single gene level, several studies have identified changes in epigenetic modifications in genes expressed in the kidney that correlate with the development of hypertension. Systematic analysis and integration of epigenetic marks at the genome-wide scale, demonstration of cellular and physiological roles of specific epigenetic modifications, and investigation of inheritance are among the major challenges and opportunities for future epigenomic and epigenetic studies of hypertension.
    Seminars in Nephrology 07/2013; 33(4):392–399. · 2.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Various stimuli, including hormones and growth factors, modulate epithelial sodium channels (ENaCs), which fine-tune Na(+) absorption in the kidney. Members of the EGF family are important for maintaining transepithelial Na(+) transport, but whether EGF influences ENaC, perhaps mediating salt-sensitive hypertension, is not well understood. Here, the ENaC inhibitor benzamil attenuated the development of hypertension in Dahl salt-sensitive rats. Feeding these salt-sensitive rats a high-salt diet led to lower levels of EGF in the kidney cortex and enhanced the expression and activity of ENaC compared with feeding a low-salt diet. To directly evaluate the role of EGF in the development of hypertension and its effect on ENaC activity, we infused EGF intravenously while continuously monitoring BP of the salt-sensitive rats. Infusion of EGF decreased ENaC activity, prevented the development of hypertension, and attenuated glomerular and renal tubular damage. Taken together, these findings indicate that cortical EGF levels decrease with a high-salt diet in salt-sensitive rats, promoting ENaC-mediated Na(+) reabsorption in the collecting duct and the development of hypertension.
    Journal of the American Society of Nephrology 04/2013; · 9.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hypertension and renal damage in Dahl SS rats are associated with increased infiltrating immune cells in the kidney. To examine the role of infiltrating immune cells in this disease process, a zinc finger nuclease targeting bases 672-706 of recombination activating gene 1 (Rag1) was injected into the pronucleus of Dahl SS (SS/JrHsdMcwi) strain embryos and implanted in pseudopregnant females. This strategy yielded a rat strain with a 13 base frame-shift mutation in the target region of Rag1 and a deletion of immunoreactive Rag1 protein in the thymus. Flow cytometry demonstrated that the Rag1 null mutant rats have a significant reduction in T- and B-lymphocytes in the circulation and spleen. Studies were performed on SS and Rag1 null rats fed a 4.0% NaCl diet for three weeks. The infiltration of T-cells into the kidney following high salt was significantly blunted in the Rag1 null rats (1.7±0.6 x 10(5) cells/kidney) compared to the Dahl SS (5.6±0.9 x 10(5) cells/kidney). Accompanying the reduction in infiltration of immune cells in the kidney, mean arterial blood pressure and urinary albumin excretion rat were significantly lower in Rag1 null mutants (158±3 mmHg and 60±16 mg/day, respectively) than in SS rats (180±11 mmHg and 251±37 mg/day). Finally, a histological analysis revealed that the glomerular and tubular damage in the kidneys of the SS rats fed high salt was also attenuated in the Rag1 mutants. These studies demonstrate the importance of renal infiltration of immune cells in the pathogenesis of hypertension and renal damage in Dahl SS rats.
    AJP Regulatory Integrative and Comparative Physiology 01/2013; · 3.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: MicroRNAs (miRNAs) play important roles in biological development and disease. Much less is known about their role in normal adult physiology. The proximal convoluted tubule (PCT) and the medullary thick ascending limb (mTAL) in the kidney consist of epithelial cells with different transport activities. We identified 55 possible miRNA-target pairs of which the miRNAs and their predicted target proteins, many of which are involved in epithelial transport, were inversely enriched in PCT and mTAL. Some miRNAs appeared to have synergistic effects on shared targets. miR-192 and its predicted target the β-1 subunit of Na(+)/K(+)-ATPase (Atp1b1), an enzyme providing the driving force for tubular transport, were inversely enriched in kidney regions. In mice, knockdown of miR-192 led to up-regulation of Atp1b1 protein. When mice were fed with a high-salt diet, knockdown of miR-192 blunted the adaptational increase of urine output. Interestingly, miR-192 appeared to target Atp1b1 through the 5'-, rather than 3'-untranslated region. The study suggests a novel physiological mechanism in which miR-192 suppresses Na(+)/K(+)-ATPase and contributes to renal handling of fluid balance. It supports an important role of miRNAs in determining cellular characteristics that may appear subtle yet are physiologically critical.
    Nucleic Acids Research 12/2012; · 8.81 Impact Factor
  • Niwanthi W Rajapakse, David L Mattson
    [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE OF REVIEW: L-Arginine (L-Arg) is the substrate for nitric oxide (NO) formation. Reduced NO bioavailability, particularly within the renal circulation, has been identified as a key factor in the pathogenesis of hypertension. This review focuses on the pathogenic role of abnormal L-Arg transport, particularly within the kidney, in hypertension. RECENT FINDINGS: Most recent studies have attempted to restore NO bioavailability in cardiovascular diseases with the use of antioxidants to reduce NO inactivation, but this approach has failed to provide beneficial effects in the clinical setting. We argue that this may be due to reduced NO formation in hypertension, which has largely been overlooked as a means of restoring NO bioavailability in cardiovascular diseases. Recent data indicate that renal L-Arg transport plays an important role in regulating both renal perfusion and function and the long-term set point of arterial pressure in health. Perturbations in the renal L-Arg transport system can give rise to abnormal renal perfusion and function, initiating hypertension and related renal damage. SUMMARY: Accordingly, we propose that L-Arg transporters are a new treatment target in hypertension and in disease states where renal NO bioavailability is disturbed.
    Current opinion in nephrology and hypertension 10/2012; · 3.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Low renal nitric oxide (NO) bioavailability contributes to the development and maintenance of chronic hypertension. We investigated whether impaired l-arginine transport contributes to low renal NO bioavailability in hypertension. Responses of renal medullary perfusion and NO concentration to renal arterial infusions of the l-arginine transport inhibitor l-lysine (10 μmol·kg(-1)·min(-1); 30 min) and subsequent superimposition of l-arginine (100 μmol·kg(-1)·min(-1); 30 min), the NO synthase inhibitor N(G)-nitro-l-arginine (2.4 mg/kg; iv bolus), and the NO donor sodium nitroprusside (0.24 μg·kg(-1)·min(-1)) were examined in Sprague-Dawley rats (SD) and spontaneously hypertensive rats (SHR). Renal medullary perfusion and NO concentration were measured by laser-Doppler flowmetry and polarographically, respectively, 5.5 mm below the kidney surface. Renal medullary NO concentration was less in SHR (53 ± 3 nM) compared with SD rats (108 ± 12 nM; P = 0.004). l-Lysine tended to reduce medullary perfusion (-15 ± 7%; P = 0.07) and reduced medullary NO concentration (-9 ± 3%; P = 0.03) while subsequent superimposition of l-arginine reversed these effects of l-lysine in SD rats. In SHR, l-lysine and subsequent superimposition of l-arginine did not significantly alter medullary perfusion or NO concentration. Collectively, these data suggest that renal l-arginine transport is impaired in SHR. Renal l-[(3)H]arginine transport was less in SHR compared with SD rats (P = 0.01). Accordingly, we conclude that impaired arginine transport contributes to low renal NO bioavailability observed in the SHR kidney.
    AJP Renal Physiology 03/2012; 302(12):F1554-62. · 4.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: NAD(P)H oxidase has been shown to be important in the development of salt-sensitive hypertension. Here, we show that the expression of a subunit of NAD(P)H oxidase, p67(phox), was increased in response to a high-salt diet in the outer renal medulla of the Dahl salt-sensitive (SS) rat, an animal model for human salt-sensitive hypertension. The higher expression of p67(phox), not the other subunits observed, was associated with higher NAD(P)H oxidase activity and salt sensitivity in SS rats compared with a salt-resistant strain. Genetic mutations of the SS allele of p67(phox) were found in the promoter region and contributed to higher promoter activity than that of the salt-resistant strain. To verify the importance of p67(phox), we disrupted p67(phox) in SS rats using zinc-finger nucleases. These rats exhibited a significant reduction of salt-sensitive hypertension and renal medullary oxidative stress and injury. p67(phox) could represent a target for salt-sensitive hypertension therapy.
    Cell metabolism 02/2012; 15(2):201-8. · 17.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The nephron number at birth is a quantitative trait that correlates inversely with the risk of hypertension and chronic kidney disease later in life. During kidney development, the nephron number is controlled by multiple factors including genetic, epigenetic, and environmental modifiers. Premature birth, which represents more than 12% of annual live births in the United States, has been linked to low nephron number and the development of hypertension later in life. In this report, we describe the development of a mouse model of prematurity-induced reduction of nephron number. Premature mice, delivered 1 and 2 days early, have 17.4 ± 2.3% (n = 6) and 23.6 ± 2% (n = 10) fewer nephrons, respectively, when compared with full-term animals (12,252 ± 571 nephrons/kidney, n = 10). After 5 weeks of age, the mice delivered 2 days premature show lower real-time glomerular filtration rate (GFR, 283 ± 13 vs 389 ± 26 μL/min). The premature mice also develop hypertension (mean arterial pressure [MAP], 134 ± 18 vs 120 ± 14 mm Hg) and albuminuria (286 ± 83 vs 176 ± 59 μg albumin/mg creatinine). This mouse model provides a proof of concept that prematurity leads to reduced nephron number and hypertension, and this model will be useful in studying the pathophysiology of prematurity-induced nephron number reductions and hypertension.
    Translational research : the journal of laboratory and clinical medicine. 02/2012; 159(2):80-9.
  • Biophysical Journal 01/2012; 102(3):651-. · 3.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sodium reabsorption via the epithelial Na(+) channel (ENaC) in the aldosterone-sensitive distal nephron plays a central role in the regulation of body fluid volume. Previous studies have indicated that arachidonic acid (AA) and its metabolite 11,12-EET but not other regioisomers of EETs inhibit ENaC activity in the collecting duct. The goal of this study was to investigate the endogenous metabolism of AA in cultured mpkCCD(c14) principal cells and the effects of these metabolites on ENaC activity. Liquid chromatography/mass spectrometry analysis of the mpkCCD(c14) cells indicated that these cells produce prostaglandins, 8,9-EET, 11,12-EET, 14,15-EET, 5-HETE, 12/8-HETE, and 15-HETE, but not 20-HETE. Single-channel patch-clamp experiments revealed that 8,9-EET, 14,15-EET, and 11,12-EET all decrease ENaC activity. Neither 5-, 12-, nor 15-HETE had any effect on ENaC activity. Diclofenac and ibuprofen, inhibitors of cyclooxygenase, decreased transepithelial Na(+) transport in the mpkCCD(c14) cells. Inhibition of cytochrome P-450 (CYP450) with MS-PPOH activated ENaC-mediated sodium transport when cells were pretreated with AA and diclofenac. Coexpression of CYP2C8, but not CYP4A10, with ENaC in Chinese hamster ovary cells significantly decreased ENaC activity in whole-cell experiments, whereas 11,12-EET mimicked this effect. Thus both endogenously formed EETs and their exogenous application decrease ENaC activity. Downregulation of ENaC activity by overexpression of CYP2C8 was PKA dependent and was prevented by myristoylated PKI treatment. Biotinylation experiments and single-channel analysis revealed that long-term treatment with 11,12-EET and overexpression of CYP2C8 decreased the number of channels in the membrane. In contrast, the acute inhibitory effects are mediated by a decrease in the open probability of the ENaC. We conclude that 11,12-EET, 8,9-EET, and 14,15-EET are endogenously formed eicosanoids that modulate ENaC activity in the collecting duct.
    AJP Renal Physiology 06/2011; 301(3):F672-81. · 4.42 Impact Factor
  • N W Rajapakse, D L Mattson
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine whether reduced renal arginine transport increases the responsiveness of the renal circulation to angiotensin II in salt sensitivity, renal perfusion responses to angiotensin II were examined in the presence of L-arginine transport inhibitor, L-lysine and subsequent L-arginine in Sprague Dawley (SD) and Dahl salt-sensitive (Dahl S) rats. Laser Doppler probes and a transonic flow probe were used to measure regional renal perfusion and total renal perfusion respectively. Renal perfusion responses to intravenous (i.v.) angiotensin II were sequentially examined under control conditions and during i.v. infusion of L-lysine, L-arginine or nitric oxide synthase inhibitor, N(G)-nitro-L-arginine. Angiotensin II (10 and 100 ng kg(-1) min(-1) , i.v.) reduced total renal (-10 ± 3 and -36 ± 5%) and cortical (-10 ± 2 and -28 ± 4%) but not medullary perfusion in SD rats. In these rats L-lysine enhanced the renal perfusion response (P = 0.003), whereas subsequent L-arginine reversed this effect (P = 0.04). Angiotensin II reduced total renal, cortical and medullary perfusion in Dahl S rats. In Dahl S rats fed high salt, L-lysine did not affect renal perfusion responses to angiotensin II, but subsequent L-arginine blunted the renal blood flow response (P = 0.01) and increased the medullary perfusion during angiotensin II infusion (P = 0.006). Intact renal L-arginine transport attenuates the vasoconstrictor effects of circulating angiotensin II in the renal cortex in SD rats. L-arginine also plays an important role in protecting the renal medullary circulation from the ischemic effects of angiotensin II in Dahl S rats.
    Acta Physiologica 06/2011; 203(3):391-400. · 4.25 Impact Factor

Publication Stats

2k Citations
414.13 Total Impact Points


  • 1993–2013
    • Medical College of Wisconsin
      • Department of Physiology
      Milwaukee, Wisconsin, United States
  • 2012
    • Baker IDI Heart and Diabetes Institute
      Melbourne, Victoria, Australia
  • 2008
    • Monash University (Australia)
      • Department of Physiology
      Melbourne, Victoria, Australia
  • 2004–2006
    • University of North Carolina at Chapel Hill
      • Department of Pathology and Laboratory Medicine
      Chapel Hill, NC, United States
  • 2002
    • University of Maryland, Baltimore
      • Division of Nephrology
      Baltimore, MD, United States
  • 2000–2002
    • Semmelweis University
      Budapeŝto, Budapest, Hungary
  • 1997
    • University of São Paulo
      San Paulo, São Paulo, Brazil
  • 1995
    • University of Greifswald
      • Institute of Physiology
      Greifswald, Mecklenburg-Vorpommern, Germany