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The renin-angiotensin system in adipose tissue and its metabolic consequences during obesity. J Nutr Biochem 2013; 24:2003-15. [PMID: 24120291 DOI: 10.1016/j.jnutbio.2013.07.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 05/24/2013] [Accepted: 07/22/2013] [Indexed: 02/07/2023]
Abstract
Obesity is a worldwide disease that is accompanied by several metabolic abnormalities such as hypertension, hyperglycemia and dyslipidemia. The accelerated adipose tissue growth and fat cell hypertrophy during the onset of obesity precedes adipocyte dysfunction. One of the features of adipocyte dysfunction is dysregulated adipokine secretion, which leads to an imbalance of pro-inflammatory, pro-atherogenic versus anti-inflammatory, insulin-sensitizing adipokines. The production of renin-angiotensin system (RAS) components by adipocytes is exacerbated during obesity, contributing to the systemic RAS and its consequences. Increased adipose tissue RAS has been described in various models of diet-induced obesity (DIO) including fructose and high-fat feeding. Up-regulation of the adipose RAS by DIO promotes inflammation, lipogenesis and reactive oxygen species generation and impairs insulin signaling, all of which worsen the adipose environment. Consequently, the increase of circulating RAS, for which adipose tissue is partially responsible, represents a link between hypertension, insulin resistance in diabetes and inflammation during obesity. However, other nutrients and food components such as soy protein attenuate adipose RAS, decrease adiposity, and improve adipocyte functionality. Here, we review the molecular mechanisms by which adipose RAS modulates systemic RAS and how it is enhanced in obesity, which will explain the simultaneous development of metabolic syndrome alterations. Finally, dietary interventions that prevent obesity and adipocyte dysfunction will maintain normal RAS concentrations and effects, thus preventing metabolic diseases that are associated with RAS enhancement.
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Ajibola CF, Fashakin JB, Fagbemi TN, Aluko RE. Renin and angiotensin converting enzyme inhibition with antioxidant properties of African yam bean protein hydrolysate and reverse-phase HPLC-separated peptide fractions. Food Res Int 2013. [DOI: 10.1016/j.foodres.2012.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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53
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Persson PB. Nitric oxide can directly mediate renin cell recruitment. Hypertension 2013; 61:286-7. [PMID: 23297373 DOI: 10.1161/hypertensionaha.111.00483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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54
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The Prorenin and (Pro)renin Receptor: New Players in the Brain Renin-Angiotensin System? Int J Hypertens 2012; 2012:290635. [PMID: 23316344 PMCID: PMC3536329 DOI: 10.1155/2012/290635] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/26/2012] [Accepted: 12/05/2012] [Indexed: 12/22/2022] Open
Abstract
It is well known that the brain renin-angiotensin (RAS) system plays an essential role in
the development of hypertension, mainly through the modulation of autonomic activities
and vasopressin release. However, how the brain synthesizes angiotensin (Ang) II has
been a debate for decades, largely due to the low renin activity. This paper first
describes the expression of the vasoconstrictive arm of RAS components in the brain as
well as their physiological and pathophysiological significance. It then focus on the
(pro)renin receptor (PRR), a newly discovered component of the RAS which has a high
level in the brain. We review the role of prorenin and PRR in peripheral organs and
emphasize the involvement of brain PRR in the pathogenesis of hypertension. Some
future perspectives in PRR research are heighted with respect to novel therapeutic
target for the treatment of hypertension and other cardiovascular diseases.
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55
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Long Y, Zhang LF, Zhang Y, Zhang CY. Single Quantum Dot Based Nanosensor for Renin Assay. Anal Chem 2012; 84:8846-52. [DOI: 10.1021/ac302284s] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Yi Long
- Single-Molecule Detection and
Imaging Laboratory, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Guangdong 518055, China
| | - Ling-fei Zhang
- Single-Molecule Detection and
Imaging Laboratory, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Guangdong 518055, China
- Weihai Municipal Center for Disease Control and Prevention, Shandong
264200, China
| | - Yan Zhang
- Single-Molecule Detection and
Imaging Laboratory, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Guangdong 518055, China
| | - Chun-yang Zhang
- Single-Molecule Detection and
Imaging Laboratory, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Guangdong 518055, China
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Prieto MC, Das S, Somanna NK, Harrison-Bernard LM, Navar LG, Pandey KN. Disruption of Npr1 gene differentially regulates the juxtaglomerular and distal tubular renin levels in null mutant mice. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2012; 4:128-139. [PMID: 23071870 PMCID: PMC3466495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/07/2012] [Indexed: 06/01/2023]
Abstract
Atrial natriuretic peptide (ANP) exerts an inhibitory effect on juxtaglomerular (JG) renin synthesis and release by activating guanylyl cyclase/ natriuretic peptide receptor-A (GC-A/NPRA). Renin has also been localized in connecting tubule cells; however, the effect of ANP/NPRA signaling on tubular renin has not been determined. In the present study, we determined the role of NPRA in regulating both JG and tubular renin using Npr1 (coding for NPRA) gene-disrupted mice, which exhibit a hypertensive phenotype. Renin-positive immunoreactivity in Npr1(-/-) homozygous null mutant mice was significantly reduced compared with Npr1(+/+) wild-type mice (23% vs 69% renin-positive glomeruli). However, after chronic diuretic treatment, Npr1(-/-) mice showed an increment of JG renin immunoreactivity compared with Npr1(+/+) mice (70% vs 81% renin-positive glomeruli). There were no significant differences in the distal tubule renin between Npr1(+/+) and Npr1(-/-) mice. However, after diuretic treatment, Npr1(-/-) mice showed a significant decrease in renin immunoreactivity in principal cells of cortical collecting ducts (p<0.05). The increased JG renin immunoreactivity after reduction in blood pressure in diuretic-treated Npr1(-/-) mice, demonstrates an inhibitory action of ANP/NPRA system on JG renin; however, a decreased expression of distal tubular renin suggests a differential effect of ANP/NPRA signaling on JG and distal tubular renin.
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Affiliation(s)
- Minolfa C Prieto
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Subhankar Das
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Naveen K Somanna
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | | | - L Gabriel Navar
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Kailash N Pandey
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
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57
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Shimakage A, Shinbo M, Yamada S. ACE inhibitory substances derived from soy foods. ACTA ACUST UNITED AC 2012. [DOI: 10.14533/jbm.12.72] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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58
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Ajibola CF, Eleyinmi AF, Aluko RE. Kinetics of the inhibition of renin and angiotensin i converting enzyme by polar and non-polar polyphenolic extracts of Vernonia amygdalina and Gongronema latifolium leaves. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2011; 66:320-327. [PMID: 21964876 DOI: 10.1007/s11130-011-0257-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study was to determine the in vitro modulation of the renin-angiotensin system by polyphenolic extracts and fractions of two green leafy vegetables, Vernonia amygdalina (VA) and Gongronema latifolium (GL), that are used for food and medicinal purposes. An 80% acetone extract of each leaf was fractionated on silicic acid-packed column to give two main fractions: acetone eluate (flow-through) and ethanol eluate (column-bound), that consist mostly of chlorophyllic and non-chlorophyllic fractions, respectively. Column fractionation resulted in polyphenolic fractions that displayed higher potency against angiotensin converting enzyme (ACE) and renin than the crude acetone extracts; generally, the chlorophyllic fraction was more active than the non-chlorophyllic fraction. ACE-inhibitory activity was significantly higher (p < 0.05) for the chlorophyllic fraction of VA than GL, with IC(50) values of 0.207 and 0.413 mg/ml, respectively. Similarly, the chlorophyllic fraction of VA had significantly higher (p < 0.05) renin inhibition than GL, with IC(50) values of 0.172 and 0.513 mg/ml, respectively. Kinetics studies showed that the chlorophyllic fractions of VA and GL exhibited mostly mixed-type ACE and renin inhibitions. We concluded that the hydrophobic nature of the chlorophyllic fraction may have contributed to the increased interaction with enzyme protein and inhibition of activities of ACE and renin.
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Affiliation(s)
- Comfort F Ajibola
- Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria
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59
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Abstract
The appearance of multicellular organisms imposed the development of several mechanisms for cell-to-cell communication, whereby different types of cells coordinate their function. Some of these mechanisms depend on the intercellular diffusion of signal molecules in the extracellular spaces, whereas others require cell-to-cell contact. Among the latter mechanisms, those provided by the proteins of the connexin family are widespread in most tissues. Connexin signaling is achieved via direct exchanges of cytosolic molecules between adjacent cells at gap junctions, for cell-to-cell coupling, and possibly also involves the formation of membrane "hemi-channels," for the extracellular release of cytosolic signals, direct interactions between connexins and other cell proteins, and coordinated influence on the expression of multiple genes. Connexin signaling appears to be an obligatory attribute of all multicellular exocrine and endocrine glands. Specifically, the experimental evidence we review here points to a direct participation of the Cx36 isoform in the function of the insulin-producing β-cells of the endocrine pancreas, and of the Cx40 isoform in the function of the renin-producing juxtaglomerular epithelioid cells of the kidney cortex.
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Affiliation(s)
- Domenico Bosco
- Department of Surgery, University of Geneva Medical School, Geneva, Switzerland
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60
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Brandon AE, Boyce AC, Lumbers ER, Kumarasamy V, Gibson KJ. Programming of the renin response to haemorrhage by mild maternal renal impairment in sheep. Clin Exp Pharmacol Physiol 2011; 38:102-8. [PMID: 21182536 DOI: 10.1111/j.1440-1681.2010.05473.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The aim of the present study was to test the hypothesis that the renin response to mechanisms activated by haemorrhage is programmed by exposure to maternal renal dysfunction. 2. In 26-27-day-old lambs born to ewes that had reduced renal function (STNxL, n=10) and lambs born to ewes with normal renal function (ConL, n=6), 1.6 mL/kg per min of blood was removed over 10 min. 3. Under basal conditions, the STNxL group had increased mean arterial pressure (P < 0.05). In response to haemorrhage, mean arterial pressure decreased in the STNxL group (P < 0.001), but there was no significant change in the ConL group. 4. Although plasma renin level increased in both groups (P < 0.05), the peak response was reduced and delayed in the STNxL group. In contrast, the rise in arginine vasopressin (AVP) level was similar in both groups and occurred over the same time course. At 24 h, both plasma renin and AVP level were the same as those measured before haemorrhage in both groups. Kidney renin level was similar in the two groups. 5. The attenuated renin response to haemorrhage in the STNxL group might explain the inability to maintain arterial pressure after haemorrhage. The results of the present study suggest that the renin response of the postnatal kidney to reductions in blood volume can be affected by the intrauterine environment. If these changes persist into adulthood, it suggests that permanent programming has occurred. Thus, the ability of an individual to respond to acute severe reductions in blood volume might be determined during intrauterine life.
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Affiliation(s)
- Amanda E Brandon
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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61
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Kitamura E, Gribanova YE, Farber DB. Regulation of retinoschisin secretion in Weri-Rb1 cells by the F-actin and microtubule cytoskeleton. PLoS One 2011; 6:e20707. [PMID: 21738583 PMCID: PMC3124475 DOI: 10.1371/journal.pone.0020707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 05/10/2011] [Indexed: 11/19/2022] Open
Abstract
Retinoschisin is encoded by the gene responsible for X-linked retinoschisis (XLRS), an early onset macular degeneration that results in a splitting of the inner layers of the retina and severe loss in vision. Retinoschisin is predominantly expressed and secreted from photoreceptor cells as a homo-oligomer protein; it then associates with the surface of retinal cells and maintains the retina cellular architecture. Many missense mutations in the XLRS1 gene are known to cause intracellular retention of retinoschisin, indicating that the secretion process of the protein is a critical step for its normal function in the retina. However, the molecular mechanisms underlying retinoschisin's secretion remain to be fully elucidated. In this study, we investigated the role of the F-actin cytoskeleton in the secretion of retinoschisin by treating Weri-Rb1 cells, which are known to secrete retinoschisin, with cytochalasin D, jasplakinolide, Y-27632, and dibutyryl cGMP. Our results show that cytochalasin D and jasplakinolide inhibit retinoschisin secretion, whereas Y-27632 and dibutyryl cGMP enhance secretion causing F-actin alterations. We also demonstrate that high concentrations of taxol, which hyperpolymerizes microtubules, inhibit retinoschisin secretion. Our data suggest that retinoschisin secretion is regulated by the F-actin cytoskeleton, that cGMP or inhibition of ROCK alters F-actin structure enhancing the secretion, and that the microtubule cytoskeleton is also involved in this process.
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Affiliation(s)
- Eiko Kitamura
- Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yekaterina E. Gribanova
- Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Debora B. Farber
- Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
- Brain Research Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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62
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Patil J, Stucki S, Nussberger J, Schaffner T, Gygax S, Bohlender J, Imboden H. Angiotensinergic and noradrenergic neurons in the rat and human heart. ACTA ACUST UNITED AC 2011; 167:31-41. [DOI: 10.1016/j.regpep.2010.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/28/2010] [Accepted: 11/25/2010] [Indexed: 11/29/2022]
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63
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Takahashi S, Ono H, Gotoh T, Yoshizawa-Kumagaye K, Sugiyama T. Novel internally quenched fluorogenic substrates for angiotensin I-converting enzyme and carboxypeptidase Y. Biomed Res 2011; 32:407-11. [DOI: 10.2220/biomedres.32.407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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64
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Gauvreau D, Hughes GJ, Lau SYW, McKay DJ, O'Shea PD, Sidler RR, Yu B, Davies IW. Practical synthesis of a renin inhibitor via a diastereoselective Dieckmann cyclization. Org Lett 2010; 12:5146-9. [PMID: 20945851 DOI: 10.1021/ol102131e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A scalable synthesis of a potent renin inhibitor (1) is described. The absolute stereochemistry is set via an unprecedented diastereoselective Dieckmann cyclization directed by a remote chiral protecting group. This transformation enables preparation of chiral 1,3-[3.3.1]-diazabicyclononenes by desymmetrization of alkyl-esters, with selectivities ranging from 4 to 17:1.
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Affiliation(s)
- Danny Gauvreau
- Merck Frosst, Centre for Therapeutic Research, Department of Process Research, 16711 TransCanada Highway, Kirkland, Québec, Canada, H9H 3L1.
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65
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Hiwatashi K, Shirakawa H, Hori K, Yoshiki Y, Suzuki N, Hokari M, Komai M, Takahashi S. Reduction of blood pressure by soybean saponins, renin inhibitors from soybean, in spontaneously hypertensive rats. Biosci Biotechnol Biochem 2010; 74:2310-2. [PMID: 21071835 DOI: 10.1271/bbb.100328] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The effect of commercial purified soybean saponin on renin activity and blood pressure was investigated. Soybean saponin significantly inhibited human renin in vitro with IC(50)=59.9 µg/ml. Orally administered soybean saponin at 80 mg/kg of body weight per day to spontaneously hypertensive rats for 8 weeks significantly decreased the blood pressure.
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Affiliation(s)
- Kazuyuki Hiwatashi
- Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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66
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The occurrence of renin inhibitor in rice: isolation, identification, and structure-function relationship. Biosci Biotechnol Biochem 2010; 74:1713-5. [PMID: 20699562 DOI: 10.1271/bbb.100233] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We found renin inhibitory activity in rice. The physico-chemical data on the isolated inhibitors were identical to those of oleic acid and linoleic acid. Oleic acid and linoleic acid competitively inhibited renin activity, with K(i) values of 15.8 and 19.8 microM respectively. Other unsaturated free fatty acids also inhibited renin activity, but saturated fatty acids had no effect on it.
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67
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Abstract
Renin is the most important enzyme in the renin-angiotensin system. Our previous study led to the identification of soyasaponin I, the first renin inhibitor isolated from soybean. In the present study, the effects of saponins and sapogenols on human renin activities were investigated. Soyasaponins I and II, glycyrrhizin, monoglucuronyl glycyrrhetic acid (MGGA), chikusetsusaponin IV, and Kochia scoparia fruit saponins (momordins) were found to inhibit renin activity. On the other hand, sapogenols (soyasapogenol B and glycyrrhetic acid), saikosaponins b2 and c, and ginsenoside Rb(1) had no effect on renin activity. These results clearly indicate that the 3-O-beta-dglucopyranosiduronic moiety in saponins (glucuronide saponin) is essential for renin inhibition.
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68
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Feliers D, Kasinath BS. Mechanism of VEGF expression by high glucose in proximal tubule epithelial cells. Mol Cell Endocrinol 2010; 314:136-42. [PMID: 19765632 PMCID: PMC2783935 DOI: 10.1016/j.mce.2009.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/31/2009] [Accepted: 09/09/2009] [Indexed: 01/13/2023]
Abstract
Angiotensin II (Ang II) and vascular endothelial growth factor (VEGF) are important mediators of kidney injury in diabetes. VEGF expression is increased in proximal tubules of mice with type 1 diabetes. In mouse proximal tubular epithelial cells (MCT) cultured with 30 mM glucose (HG) for 24h, VEGF expression is increased at the protein and the mRNA level, suggesting a transcriptional mechanism. HG stimulation of VEGF synthesis is prevented by captopril, an inhibitor of angiotensin-converting enzyme, and, by losartan, a specific antagonist of angiotensin type 1 receptor (AT1), suggesting that VEGF synthesis is mediated by Ang II. Synthesis of angiotensinogen (AGT), a precursor of angiotensin II, is increased in MCTs cultured in HG. Although synthesis of renin and ACE is not affected by HG, their activity is increased in the conditioned medium. Concentrations of Ang I and Ang II are also increased in conditioned medium from HG-treated MCTs and captopril prevents increased Ang II, but not Ang I, synthesis. Finally, AT1 is activated in MCTs treated with HG, and its activation is prevented by captopril and losartan. The ERK pathway is activated by HG within minutes of stimulation and lasting for up to 24h. The initial phase of ERK activation is due to HG itself and leads to AGT upregulation and the sustained phase is mediated for the most part by Ang II-activated AT1 receptor and leads to increased VEGF synthesis. These data show that: (1) HG increases AGT synthesis and activation of renin and ACE by MCTs, leading to local production of Ang I and Ang II. (2) Ang II activates endogenous AT1 and stimulates synthesis of VEGF. (3) HG activation of ERK starts within minutes and lasts for up to 24h. Early ERK activation is involved in AGT upregulation and sustained ERK activation, mediated via AT1, is responsible for VEGF synthesis. In conclusion, our study shows that MCTs express an endogenous renin-angiotensin system that is activated by high glucose to stimulate the synthesis of VEGF, through activation of the ERK pathway.
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Affiliation(s)
- Denis Feliers
- O'Brien Kidney Research Center, Department of Medicine/Nephrology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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69
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Bell PD, Komlosi P, Zhang ZR. ATP as a mediator of macula densa cell signalling. Purinergic Signal 2009; 5:461-71. [PMID: 19330465 PMCID: PMC2776136 DOI: 10.1007/s11302-009-9148-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022] Open
Abstract
Within each nephro-vascular unit, the tubule returns to the vicinity of its own glomerulus. At this site, there are specialised tubular cells, the macula densa cells, which sense changes in tubular fluid composition and transmit information to the glomerular arterioles resulting in alterations in glomerular filtration rate and blood flow. Work over the last few years has characterised the mechanisms that lead to the detection of changes in luminal sodium chloride and osmolality by the macula densa cells. These cells are true "sensor cells" since intracellular ion concentrations and membrane potential reflect the level of luminal sodium chloride concentration. An unresolved question has been the nature of the signalling molecule(s) released by the macula densa cells. Currently, there is evidence that macula densa cells produce nitric oxide via neuronal nitric oxide synthase (nNOS) and prostaglandin E(2) (PGE(2)) through cyclooxygenase 2 (COX 2)-microsomal prostaglandin E synthase (mPGES). However, both of these signalling molecules play a role in modulating or regulating the macula-tubuloglomerular feedback system. Direct macula densa signalling appears to involve the release of ATP across the basolateral membrane through a maxi-anion channel in response to an increase in luminal sodium chloride concentration. ATP that is released by macula densa cells may directly activate P2 receptors on adjacent mesangial cells and afferent arteriolar smooth muscle cells, or the ATP may be converted to adenosine. However, the critical step in signalling would appear to be the regulated release of ATP across the basolateral membrane of macula densa cells.
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Affiliation(s)
- P Darwin Bell
- Department of Medicine, Division of Nephrology, Children's Research Institute, Medical University of South Carolina, Charleston, SC, USA,
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70
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Rehsia NS, Dhalla NS. Potential of endothelin-1 and vasopressin antagonists for the treatment of congestive heart failure. Heart Fail Rev 2009; 15:85-101. [DOI: 10.1007/s10741-009-9152-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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71
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Ortiz-Capisano MC, Liao TD, Ortiz PA, Beierwaltes WH. Calcium-dependent phosphodiesterase 1C inhibits renin release from isolated juxtaglomerular cells. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1469-76. [PMID: 19741056 DOI: 10.1152/ajpregu.00121.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Renin release from the juxtaglomerular (JG) cell is stimulated by the second messenger cAMP and inhibited by calcium. We previously showed JG cells contain a calcium sensing receptor (CaSR), which, when stimulated, decreases cAMP formation and inhibits renin release. We hypothesize CaSR activation decreases cAMP and renin release, in part, by stimulating a calcium calmodulin-activated phosphodiesterase 1 (PDE1). We incubated our primary culture of JG cells with two selective PDE1 inhibitors [8-methoxymethil-IBMX (8-MM-IBMX; 20 microM) and vinpocetine (40 microM)] and the calmodulin inhibitor W-7 (10 microM) and measured cAMP and renin release. Stimulation of the JG cell CaSR with the calcimimetic cinacalcet (1 microM) resulted in decreased cAMP from a basal of 1.13 +/- 0.14 to 0.69 +/- 0.08 pM/mg protein (P < 0.001) and in renin release from 0.89 +/- 0.16 to 0.38 +/- 0.08 microg ANG I/mlxh(-1)xmg protein(-1) (P < 0.001). However, the addition of 8-MM-IBMX with cinacalcet returned both cAMP (1.10 +/- 0.19 pM/mg protein) and renin (0.57 +/- 0.16 microg ANG I/mlxh(-1)xmg protein(-1)) to basal levels. Similar results were obtained with vinpocetine, and also with W-7. Combining 8-MM-IBMX and W-7 had no additive effect. To determine which PDE1 isoform is involved, we performed Western blot analysis for PDE1A, B, and C. Only Western blot analysis for PDE1C showed a characteristic band apparent at 80 kDa. Immunofluorescence showed cytoplasmic distribution of PDE1C and renin in the JG cells. In conclusion, PDE1C is expressed in isolated JG cells, and contributes to calcium's inhibitory modulation of renin release from JG cells.
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Affiliation(s)
- M Cecilia Ortiz-Capisano
- Department of Medicine, Hypertension and Vascular Research Division, Henry Ford Hospital, Detroit, Michigan 48202, USA
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72
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The influence of heart failure self-care on health outcomes: hypothetical cardioprotective mechanisms. J Cardiovasc Nurs 2009; 24:179-87; quiz 188-9. [PMID: 19279494 DOI: 10.1097/jcn.0b013e31819b5419] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lapses in self-care are commonly cited as a major cause of poor outcomes in persons with heart failure (HF). Not surprisingly, self-care is assumed to be central to improving health outcomes in this patient population. Empirically, however, this assumption is not well supported, and mechanistically, relationships between self-care and outcomes in HF have not yet been described. In this review, it is proposed that effective self-care maintenance (adherence) and self-care management (symptom evaluation and management) practices are complementary to optimal medical management in delaying HF progression and improving health outcomes in this population. Potential mechanisms through which effective HF self-care practices are complementary to pharmacological therapy in improving outcomes include (a) facilitating partial blockade and partial deactivation of deleterious neurohormones, (b) limiting inflammatory processes, (c) decreasing the need for administration of detrimental pharmacological agents, and (d) minimizing myocardial hibernation. Because these mechanisms are hypothetical, research findings are required to establish their validity. Several strategic research questions are proposed.
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73
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Fowler JD, Johnson ND, Haroldson TA, Brintnall JA, Herrera JE, Katz SA, Bernlohr DA. Regulated renin release from 3T3-L1 adipocytes. Am J Physiol Endocrinol Metab 2009; 296:E1383-91. [PMID: 19293336 PMCID: PMC2692391 DOI: 10.1152/ajpendo.00025.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Whereas adipose tissue possesses a local renin-angiotensin system, the synthesis and regulated release of renin has not been addressed. To that end, we utilized differentiating 3T3-L1 cells and analyzed renin expression and secretion. Renin mRNA expression and protein enzymatic activity were not detectable in preadipocytes. However, upon differentiation, renin mRNA and both intracellular and extracellular renin activity were upregulated. In differentiated adipocytes, forskolin treatment resulted in a 28-fold increase in renin mRNA, whereas TNFalpha treatment decreased renin mRNA fourfold. IL-6, insulin, and angiotensin (Ang) II were without effect. In contrast, forskolin and TNFalpha each increased renin protein secretion 12- and sevenfold, respectively. Although both forskolin and TNFalpha induce lipolysis in adipocytes, fatty acids, prostaglandin E(2), and lipopolysaccharide had no effect on renin mRNA or secretion. To evaluate the mechanism(s) by which forskolin and/or TNFalpha are able to regulate renin secretion, a general lipase inhibitor (E600) and PKA inhibitor (H89) were used. Both inhibitors attenuated forskolin-induced renin release, whereas they had no effect on TNFalpha-regulated secretion. In contrast, E600 potentiated forskolin-stimulated renin mRNA levels, whereas H89 had no effect. Neither inhibitor had any influence on TNFalpha regulation of renin mRNA. Relative to lean controls, renin expression was reduced 78% in the epididymal adipose tissue of obese male C57Bl/6J mice, consistent with TNFalpha-mediated downregulation of renin mRNA in the culture system. In conclusion, the expression and secretion of renin are regulated under a complex series of hormonal and metabolic determinants in mature 3T3-L1 adipocytes.
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Affiliation(s)
- Jason D Fowler
- Department of Integrative Biology, University of Minnesota, Minneapolis, Minnesota 55455, USA
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74
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Bezençon O, Bur D, Weller T, Richard-Bildstein S, Remeň L, Sifferlen T, Corminboeuf O, Grisostomi C, Boss C, Prade L, Delahaye S, Treiber A, Strickner P, Binkert C, Hess P, Steiner B, Fischli W. Design and Preparation of Potent, Nonpeptidic, Bioavailable Renin Inhibitors. J Med Chem 2009; 52:3689-702. [DOI: 10.1021/jm900022f] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Olivier Bezençon
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Daniel Bur
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Thomas Weller
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Sylvia Richard-Bildstein
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Luboš Remeň
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Thierry Sifferlen
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Olivier Corminboeuf
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Corinna Grisostomi
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Christoph Boss
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Lars Prade
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Stéphane Delahaye
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Alexander Treiber
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Panja Strickner
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Christoph Binkert
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Patrick Hess
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Beat Steiner
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
| | - Walter Fischli
- Drug Discovery and Preclinical Research, Actelion Pharmaceuticals Ltd., Gewerbestrasse 16, CH-4123 Allschwil, Switzerland
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75
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Current concepts of neurohormonal activation in heart failure: mediators and mechanisms. AACN Adv Crit Care 2009; 19:364-85; quiz 386-7. [PMID: 18981739 DOI: 10.1097/01.aacn.0000340718.93742.c4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neurohormonal activation is a commonly cited array of phenomena in the body's physiologic response to heart failure. Although various neurohormones and pharmacologic agents that moderate their pathophysiologic effects have been reviewed in the nursing literature, both the mechanisms of neurohormonal system activation and cellular and organ system effects have been described only in brief. Accordingly, this article reviews mechanisms of neurohormonal activation and describes cellular and cardiovascular effects of the (1) sympathetic nervous system, (2) renin-angiotensin-aldosterone system, (3) kallikrein-kininogen-kinin system, (4) vasopressinergic system, (5) natriuretic peptide systems, and (6) endothelin in the context of heart failure. This article implicitly details the physiologic basis for numerous current and potential future pharmacologic agents used in the management of heart failure. It is intended that this article be used as a reference for advanced clinical nursing practice, research, and education.
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76
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Takahashi S, Hori K, Shinbo M, Hiwatashi K, Gotoh T, Yamada S. Isolation of human renin inhibitor from soybean: soyasaponin I is the novel human renin inhibitor in soybean. Biosci Biotechnol Biochem 2008; 72:3232-6. [PMID: 19060406 DOI: 10.1271/bbb.80495] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We found human renin inhibitory activity in soybean and isolated the active compound, soybean renin inhibitor (SRI). The physico-chemical data on the isolated SRI were identical with those of soyasaponin I. SRI showed significant inhibition against recombinant human renin, with an IC(50) value of 30 microg/ml. Kinetic studies with SRI indicated partial noncompetitive inhibition, with a K(i) value of 37.5 microM. On the other hand, SRI weakly inhibited pepsin, papain, and bromeline activities, but did not inhibit other proteinases, such as trypsin, kallikrein, angiotensin converting enzyme, and aminopeptidase M. Moreover, a significant (p<0.05) decrease in the systolic blood pressure of spontaneously hypertensive rats was observed when partially purified SRI was orally administrated at 40 mg/kg/d for 7 weeks. This is the first demonstration of a renin inhibitor from soybean, soyasaponin I.
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Affiliation(s)
- Saori Takahashi
- Institute for Food and Brewing, Akita Prefectural Agricultural, Forestry, and Fisheries Research Center, Arayamachi, Akita, Japan.
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77
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Pentz ES, Lopez MLSS, Cordaillat M, Gomez RA. Identity of the renin cell is mediated by cAMP and chromatin remodeling: an in vitro model for studying cell recruitment and plasticity. Am J Physiol Heart Circ Physiol 2007; 294:H699-707. [PMID: 18055510 DOI: 10.1152/ajpheart.01152.2007] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The renin-angiotensin system (RAS) regulates blood pressure and fluid-electrolyte homeostasis. A key step in the RAS cascade is the regulation of renin synthesis and release by the kidney. We and others have shown that a major mechanism to control renin availability is the regulation of the number of cells capable of making renin. The kidney possesses a pool of cells, mainly in its vasculature but also in the glomeruli, capable of switching from smooth muscle to endocrine renin-producing cells when homeostasis is threatened. The molecular mechanisms governing the ability of these cells to turn the renin phenotype on and off have been very difficult to study in vivo. We, therefore, developed an in vitro model in which cells of the renin lineage are labeled with cyan fluorescent protein and cells actively making renin mRNA are labeled with yellow fluorescent protein. The model allowed us to determine that it is possible to culture cells of the renin lineage for numerous passages and that the memory to express the renin gene is maintained in culture and can be reenacted by cAMP and chromatin remodeling (histone H4 acetylation) at the cAMP-responsive element in the renin gene.
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Affiliation(s)
- Ellen Steward Pentz
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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78
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Wang J, Qi S, Cheng W, Li L, Wang F, Li YZ, Zhang SP. Identification, expression and tissue distribution of a renalase homologue from mouse. Mol Biol Rep 2007; 35:613-20. [PMID: 17846919 DOI: 10.1007/s11033-007-9131-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Accepted: 08/14/2007] [Indexed: 11/25/2022]
Abstract
FAD (flavin adenine dinucleotide)-dependent monoamine oxidases play very important roles in many biological processes. A novel monoamine oxidase, named renalase, has been identified in human kidney recently and is found to be markedly reduced in patients with end-stage renal disease (ESRD). Here, we reported the identification of a renalase homologue from mouse, termed mMAO-C (mouse monoamine oxidase-C) after the monoamine oxidase-A and -B (MAO-A and -B). This gene locates on the mouse chromosome 19C1 and its coding region spans 7 exons. The deuced amino acid sequences were predicted to contain a typical secretive signal peptide and a conserved amine oxidase domain. Phylogenetic analysis and multiple sequences alignment indicated that mMAO-C-like sequences exist in all examined species and share significant similarities. This gene has been submitted to the NCBI GenBank database (Accession number: DQ788834). With expression vectors generated from the cloned mMAO-C gene, exogenous protein was effectively expressed in both prokaryotic and eukaryotic cells. Recombinant mMAO-C protein was secreted out of human cell lines, indicating the biological function of its signal peptide. Moreover, tissue expression pattern analysis revealed that mMAO-C gene is predominantly expressed in the mouse kidney and testicle, which implies that kidney and testicle are the main sources of renalase secretion. Shortly, this study provides an insight into understanding the physiological and biological functions of mMAO-C and its homologues in endocrine.
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Affiliation(s)
- Jian Wang
- Laboratory for Functional Genomic Research, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, China
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79
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Abstract
PURPOSE OF REVIEW Renalase is a secreted amine oxidase that metabolizes catecholamines. The approach used to identify this novel renal hormone will be discussed, as will the experimental data suggesting it regulates cardiovascular function, and its deficiency contributes to heightened cardiovascular risks in patients with chronic kidney disease. RECENT FINDINGS The sympathetic nervous system is activated in chronic kidney disease and end-stage renal disease, and patients have a significant increase in cardiovascular disease. Parenteral administration of either native or recombinant renalase lowers blood pressure and heart rate by metabolizing circulating catecholamines. Plasma levels are markedly reduced in patients with chronic kidney disease and end-stage renal disease. Renalase deficiency occurs in salt-sensitive Dahl rats as they develop hypertension. Renalase inhibition by antisense RNA increases baseline blood pressure, and leads to an exaggerated blood pressure response to adrenergic stress. Most recently, two single nucleotide polymorphisms in the renalase gene were found to be associated with essential hypertension in humans. SUMMARY The renalase pathway is a previously unrecognized mechanism for regulating circulating catecholamines, and, therefore, cardiac function, and blood pressure. Abnormalities in the renalase pathway are evident in animal models of chronic kidney disease and hypertension. Collectively, these data suggest that renalase replacement may be an important therapeutic modality.
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Affiliation(s)
- Jianchao Xu
- Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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80
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Abstract
Renin maintains blood pressure through vasoconstriction when there is inadequate salt to maintain volume. In populations where blood pressure is more often high than low, and vascular death more common than haemorrhage or dehydration, therapeutic reductions in renin secretion or response are valuable. Whether long-term benefits are due entirely to blood pressure reduction remains unproved. The pathway can be blocked at its rate-limiting step (beta blockade or direct renin inhibition), the synthesis of the active product, angiotensin II, or at the receptor for angiotensin. Because renin and sodium are the two main factors in blood pressure control, and renin levels vary inversely with sodium load, blood pressure control requires a combination of natriuresis and blocking the consequential increase in renin activity. Being a large and stable molecule, renin is among the easiest and cheapest of hormone measurements. Understanding the simple biochemistry and physiology of renin permits optimal use of the drugs acting to raise or suppress this hormone.
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Affiliation(s)
- Morris J Brown
- Clinical Pharmacology Unit, Addenbrookes Hospital, Cambridge, UK.
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81
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Renalase is a novel renal hormone that regulates cardiovascular function. ACTA ACUST UNITED AC 2007; 1:99-103. [DOI: 10.1016/j.jash.2006.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Accepted: 12/05/2006] [Indexed: 11/22/2022]
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82
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Hassinen M, Paajanen V, Haverinen J, Eronen H, Vornanen M. Cloning and expression of cardiac Kir2.1 and Kir2.2 channels in thermally acclimated rainbow trout. Am J Physiol Regul Integr Comp Physiol 2007; 292:R2328-39. [PMID: 17289820 DOI: 10.1152/ajpregu.00354.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Potassium currents are plastic entities that modify electrical activity of the heart in various physiological conditions including chronic thermal stress. We examined the molecular basis of the inward rectifier K+ current (IK1) in rainbow trout acclimated to cold (4 degrees C, CA) and warm (18 degrees C, WA) temperature. Inward rectifier K+ channel (Kir)2.1 and Kir2.2 transcripts were expressed in atrium and ventricle of the trout heart, K(ir)2.1 being the major component in both cardiac chambers. The relative expression of Kir2.2 was, however, higher (P < 0.05) in atrium than ventricle. The density of ventricular IK1 was approximately 25% larger (P < 0.05) in WA than CA trout. Furthermore, the IK1 of the WA trout was 10 times more sensitive to Ba2+ (IC50 0.18 +/- 0.42 microM) than the IK1 of the CA trout (1.17 +/- 0.44 microM) (P < 0.05), and opening kinetics of single Kir2 channels was slower in WA than CA trout (P < 0.05). When expressed in COS-1 cells, the homomeric Kir2.2 channels demonstrated higher Ba2+ sensitivity (2.88 +/- 0.42 microM) than Kir2.1 channels (24.99 +/- 7.40 microM) (P < 0.05). In light of the different Ba2+ sensitivities of rainbow trout (om)Kir2.1 and omKir2.2 channels, it is concluded that warm acclimation increases either number or activity of the omK(ir)2.2 channels in trout ventricular myocytes. The functional changes in I(K1) are independent of omKir2 transcript levels, which remained unaltered by thermal acclimation. Collectively, these findings suggest that thermal acclimation modifies functional properties and subunit composition of the trout Kir2 channels, which may be needed for regulation of cardiac excitability at variable temperatures.
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Affiliation(s)
- Minna Hassinen
- Department of Biology, University of Joensuu, 80101 Joensuu, Finland
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83
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Perlstein TS, Gerhard-Herman M, Hollenberg NK, Williams GH, Thomas A. Insulin Induces Renal Vasodilation, Increases Plasma Renin Activity, and Sensitizes the Renal Vasculature to Angiotensin Receptor Blockade in Healthy Subjects. J Am Soc Nephrol 2007; 18:944-51. [PMID: 17287426 DOI: 10.1681/asn.2006091026] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Insulin stimulates the renin-angiotensin system and induces renal vasodilation. The relationship between these opposing influences of insulin on renal vascular tone has not been explored. A hyperinsulinemic euglycemic clamp and sham insulin clamp each of 270 min duration were performed in 15 healthy individuals during high sodium balance. An angiotensin receptor blocker was administered at time 180 min. Renal plasma flow and plasma renin activity were measured serially. The response to insulin or sham insulin infusion was defined as the change from time 0 to 180 min; the response to angiotensin receptor blockade (ARB) was defined as the change from time 180 to 270 min. Insulin infusion increased plasma renin activity (P < 0.01) and renal plasma flow (P < 0.01); the latter effect plateaued by time 150 min. ARB caused a greater vasodilator response during insulin infusion compared with during sham insulin infusion (P = 0.02). Increasing renin response to insulin predicted blunting of the renal vasodilator response to insulin infusion (R(2) = 0.36, P = 0.02) and sensitizing of the renal vasodilator response to ARB during insulin infusion (R(2) = 0.59, P < 0.01). Insulin-induced activation of the renin-angiotensin system modulates insulin-induced renal vasodilation in healthy individuals. Further studies are warranted to address this balance in states of insulin resistance and the possible implications for the association of insulin resistance with risk for chronic kidney disease.
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Affiliation(s)
- Todd S Perlstein
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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84
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De Godoy MAF, Rattan S. Autocrine regulation of internal anal sphincter tone by renin-angiotensin system: comparison with phasic smooth muscle. Am J Physiol Gastrointest Liver Physiol 2005; 289:G1164-75. [PMID: 16020656 DOI: 10.1152/ajpgi.00115.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The myogenic control mechanisms that govern the basal tone in the internal anal sphincter (IAS) are not known. The present studies determined the autocrine regulation of ANG II in the IAS. The studies were performed in the freshly isolated smooth muscle cells (SMC) of the IAS. We determined the presence of ANG II precursor angiotensinogen (Angen), and the enzymes that convert it into ANG II, using functional, molecular biology, and immunocytochemical studies in rats. ANG II levels in the SMC were determined using ELISA. The IAS SMC generate ANG II at a rate severalfold higher than those from the adjoining smooth muscle of rectum (RSM). RT-PCR data show that IAS exclusively expresses significant higher levels of renin, Angen, and angiotensin-converting enzyme (ACE). These data were confirmed using Western blot analyses and immunocytochemistry. In the IAS SMC, H-77 (10 microM; renin inhibitor) and captopril (1 microM; ACE inhibitor) decreased the basal as well as Angen-increased levels of ANG II. The following functional data corroborate the role of renin-angiotensin system (RAS) in the IAS tone. Angen produced concentration-dependent shortening of the IAS SMC that was inhibited by H-77 and captopril. In addition, H-77 or captopril caused a concentration-dependent fall in the IAS tone vs. nontonic tissues. Basal tone in IAS is partially under the autocrine control of cellular RAS evident by the expression of mRNA coding Angen, renin, and ACE and translation to the respective proteins in the SMC.
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Affiliation(s)
- Márcio A F De Godoy
- Dept. of Medicine, Division of Gastroenterology and Hepatology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Klar J, Sigl M, Obermayer B, Schweda F, Krämer BK, Kurtz A. Calcium inhibits renin gene expression by transcriptional and posttranscriptional mechanisms. Hypertension 2005; 46:1340-6. [PMID: 16286572 DOI: 10.1161/01.hyp.0000192025.86189.46] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of this study was to investigate the role of cytosolic calcium for renin gene expression in juxtaglomerular cells. For this purpose, we used the immortalized juxtaglomerular mouse cell line As4.1. To increase cytosolic calcium concentration, we treated the cells with thapsigargin and cyclopiazonic acid, inhibitors of the endoplasmatic reticulum Ca- ATPase. Thapsigargin and cyclopiazonic acid inhibited renin gene expression in a characteristic time and concentration-dependent manner. This effect was concentration-dependently blocked by BAPTA-AM, an intracellular Ca2+ chelator. Pharmacological blocking of protein kinase C activity by calphostin, Gö6976, and Gö6983 did not change the effect of thapsigargin on renin gene expression. Experiments with renin1C-promoter-reporter constructs revealed that thapsigargin inhibited renin gene transcription. Analysis of deletion constructs of the renin1C promoter indicated that regulatory elements involved in the calcium-mediated inhibition of renin gene transcription are located in the enhancer region of the renin gene and that > or =3 transcription factor-binding sites are involved in this process. In addition, thapsigargin reduced the renin mRNA half-life from 10 hours (control conditions) to 4 hours. Knockdown studies with small interfering RNA directed to dynamin-1 mRNA revealed that dynamin-1 is likely to be involved in the calcium-mediated destabilization of renin mRNA. These data suggest that calcium inhibits renin gene expression in juxtaglomerular cells via a concerted action of inhibition of renin gene transcription and destabilization of renin mRNA.
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Affiliation(s)
- Jürgen Klar
- Institut für Physiologie, Universität Regensburg, D-93040 Regensburg, Germany.
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86
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Morello F, de Boer RA, Steffensen KR, Gnecchi M, Chisholm JW, Boomsma F, Anderson LM, Lawn RM, Gustafsson JA, Lopez-Ilasaca M, Pratt RE, Dzau VJ. Liver X receptors alpha and beta regulate renin expression in vivo. J Clin Invest 2005; 115:1913-22. [PMID: 16007255 PMCID: PMC1159146 DOI: 10.1172/jci24594] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 05/10/2005] [Indexed: 12/21/2022] Open
Abstract
The renin-angiotensin-aldosterone system controls blood pressure and salt-volume homeostasis. Renin, which is the first enzymatic step of the cascade, is critically regulated at the transcriptional level. In the present study, we investigated the role of liver X receptor alpha (LXR(alpha)) and LXR(beta) in the regulation of renin. In vitro, both LXRs could bind to a noncanonical responsive element in the renin promoter and regulated renin transcription. While LXR(alpha) functioned as a cAMP-activated factor, LXR(beta) was inversely affected by cAMP. In vivo, LXRs colocalized in juxtaglomerular cells, in which LXR(alpha) was specifically enriched, and interacted with the renin promoter. In mouse models, renin-angiotensin activation was associated with increased binding of LXR(alpha) to the responsive element. Moreover, acute administration of LXR agonists was followed by upregulation of renin transcription. In LXR(alpha) mice, the elevation of renin triggered by adrenergic stimulation was abolished. Untreated LXR(beta) mice exhibited reduced kidney renin mRNA levels compared with controls. LXR(alpha)LXR(beta) mice showed a combined phenotype of lower basal renin and blunted adrenergic response. In conclusion, we show herein that LXR(alpha) and LXR(beta) regulate renin expression in vivo by directly interacting with the renin promoter and that the cAMP/LXR(alpha) signaling pathway is required for the adrenergic control of the renin-angiotensin system.
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87
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Al Kadi H, Nasrat H, Broughton Pipkin F. A prospective, longitudinal study of the renin–angiotensin system, prostacyclin and thromboxane in the first trimester of normal human pregnancy: association with birthweight. Hum Reprod 2005; 20:3157-62. [PMID: 16006463 DOI: 10.1093/humrep/dei184] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Very early human pregnancy is a state of cardiovascular underfilling. The renin-angiotensin system (RAS) is directly concerned with sodium and water homeostasis. Angiotensinogen is known to be the rate-limiting component in the generation of angiotensin I, and hence angiotensin II, in pregnancy. The usual measurement of 'renin activity' does not differentiate between enzyme and substrate. We hypothesized that the RAS is activated from the start of pregnancy; plasma renin concentration (PRC) and angiotensinogen will show differential regulation and might stimulate the rise in prostacyclin. METHODS A prospective study of 12 nulliparous normal women. PRC and angiotensinogen and excretion of prostacyclin and thromboxane metabolites were measured pre-pregnancy and four to six times after conception to 13 weeks. RESULTS By 6 weeks gestation, mean PRC was markedly raised and remained stable to 13 weeks. The initial angiotensinogen response varied, but rose consistently after 6-8 weeks. Regression analysis showed angiotensinogen in the first trimester to be strongly associated with corrected birthweight centile (P < 0.001). Excretion of eicosanoid metabolites was very variable, but rose significantly from 6 weeks; the ratio between prostacyclin and thromboxane excretion did not alter over this time. There was no correlation between the various hormones measured. CONCLUSION Angiotensinogen is known to be rate-limiting in pregnancy. Its association with birthweight may be through effects on early plasma volume expansion and may have implications for intrauterine growth restriction and pre-eclampsia.
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Affiliation(s)
- H Al Kadi
- Department of Physiology, Faculty of Medicine, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Saudi Arabia
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88
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Xu J, Li G, Wang P, Velazquez H, Yao X, Li Y, Wu Y, Peixoto A, Crowley S, Desir GV. Renalase is a novel, soluble monoamine oxidase that regulates cardiac function and blood pressure. J Clin Invest 2005; 115:1275-80. [PMID: 15841207 PMCID: PMC1074681 DOI: 10.1172/jci24066] [Citation(s) in RCA: 271] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 02/15/2005] [Indexed: 11/17/2022] Open
Abstract
The kidney not only regulates fluid and electrolyte balance but also functions as an endocrine organ. For instance, it is the major source of circulating erythropoietin and renin. Despite currently available therapies, there is a marked increase in cardiovascular morbidity and mortality among patients suffering from end-stage renal disease. We hypothesized that the current understanding of the endocrine function of the kidney was incomplete and that the organ might secrete additional proteins with important biological roles. Here we report the identification of a novel flavin adenine dinucleotide-dependent amine oxidase (renalase) that is secreted into the blood by the kidney and metabolizes catecholamines in vitro (renalase metabolizes dopamine most efficiently, followed by epinephrine, and then norepinephrine). In humans, renalase gene expression is highest in the kidney but is also detectable in the heart, skeletal muscle, and the small intestine. The plasma concentration of renalase is markedly reduced in patients with end-stage renal disease, as compared with healthy subjects. Renalase infusion in rats caused a decrease in cardiac contractility, heart rate, and blood pressure and prevented a compensatory increase in peripheral vascular tone. These results identify renalase as what we believe to be a novel amine oxidase that is secreted by the kidney, circulates in blood, and modulates cardiac function and systemic blood pressure.
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Affiliation(s)
- Jianchao Xu
- Section of Nephrology, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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89
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Hartman D, Sagnella GA, Chesters CA, Macgregor GA. Direct Renin Assay and Plasma Renin Activity Assay Compared. Clin Chem 2004; 50:2159-61. [PMID: 15339872 DOI: 10.1373/clinchem.2004.033654] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Deirdré Hartman
- Blood Pressure Unit, Department of Cardiac and Vascular Medicine, St. George's Hospital Medical School, London, UK.
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90
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Peti-Peterdi J, Fintha A, Fuson AL, Tousson A, Chow RH. Real-time imaging of renin release in vitro. Am J Physiol Renal Physiol 2004; 287:F329-35. [PMID: 15082450 DOI: 10.1152/ajprenal.00420.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renin release from juxtaglomerular granular cells is considered the rate-limiting step in activation of the renin-angiotensin system that helps to maintain body salt and water balance. Available assays to measure renin release are complex, indirect, and work with significant internal errors. To directly visualize and study the dynamics of both the release and tissue activity of renin, we isolated and perfused afferent arterioles with attached glomeruli dissected from rabbit kidneys and used multiphoton fluorescence imaging. Acidotropic fluorophores, such as quinacrine and LysoTrackers, clearly and selectively labeled renin granules. Immunohistochemistry of mouse kidney with a specific renin antibody and quinacrine staining colocalized renin granules and quinacrine fluorescence. A low-salt diet for 1 wk caused an approximately fivefold increase in the number of both individual granules and renin-positive granular cells. Time-lapse imaging showed no signs of granule trafficking or any movement, only the dimming and disappearance of fluorescence from individual renin granules within 1 s in response to 100 μM isoproterenol. There appeared to be a quantal release of the granular contents; i.e., an all-or-none phenomenon. Using As4.1 cells, a granular cell line, we observed further classic signs of granule exocytosis, the emptying of granule content associated with a flash of quinacrine fluorescence. Using a fluorescence resonance energy transfer-based, 5-(2-aminoethylamino)naphthalene-1-sulfonic acid (EDANS)-conjugated renin substrate in the bath, an increase in EDANS fluorescence (renin activity) was observed around granular cells in response to isoproterenol. Fluorescence microscopy is an excellent tool for the further study of the mechanism, regulation, and dynamics of renin release.
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Affiliation(s)
- János Peti-Peterdi
- Nephrology Research and Training Center, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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91
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Leichtle A, Rauch U, Albinus M, Benöhr P, Kalbacher H, Mack AF, Veh RW, Quast U, Russ U. Electrophysiological and molecular characterization of the inward rectifier in juxtaglomerular cells from rat kidney. J Physiol 2004; 560:365-76. [PMID: 15284349 PMCID: PMC1665251 DOI: 10.1113/jphysiol.2004.070359] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Renin, the key element of the renin-angiotensin-aldosterone system, is mainly produced by and stored in the juxtaglomerular cells in the kidney. These cells are situated in the media of the afferent arteriole close to the vessel pole and can transform into smooth muscle cells and vice versa. In this study, the electrophysiological properties and the molecular identity of the K+ channels responsible for the resting membrane potential (approximately -60 mV) of the juxtaglomerular cells were examined. In order to increase the number of juxtaglomerular cells, afferent arterioles from NaCl-depleted rats were used, and > 90% of the afferent arterioles were renin positive at the distal end of the arteriole. Whole-cell and cell-attached single-channel patch-clamp experiments showed that juxtaglomerular cells are endowed with a strongly inwardly rectifying K+ channel (Kir). The channel was highly sensitive to inhibition by Ba2+ (inhibition constant 37 microM at 0 mV), but relatively insensitive to Cs+ and, with 142 mM K+ in the pipette, had a single-channel conductance of 31.5 pS. Immunocytochemical studies showed the presence of Kir2.1 but no signal for Kir2.2 in the media of the afferent arteriole. In PCR analyses using isolated juxtaglomerular cells, the mRNA for Kir2.1 and Kir2.2 was detected. Collectively, the results show that Kir2.1 is the dominant component of the channel. The current carried by these channels plays a decisive role in setting the membrane potential of juxtaglomerular cells.
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Affiliation(s)
- Anke Leichtle
- Department of Pharmacology and Toxicology, Medical Faculty, University of Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany
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