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Zhang S, Huang Q, Wang Q, Wang Q, Cao X, Zhao L, Xu N, Zhuge Z, Mao J, Fu X, Liu R, Wilcox CS, Patzak A, Li L, Lai EY. Enhanced Renal Afferent Arteriolar Reactive Oxygen Species and Contractility to Endothelin-1 Are Associated with Canonical Wnt Signaling in Diabetic Mice. Kidney Blood Press Res 2018; 43:860-871. [PMID: 29870994 PMCID: PMC6050514 DOI: 10.1159/000490334] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 05/24/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND/AIMS Canonical Wnt signaling is involved in oxidative stress, vasculopathy and diabetes mellitus but its role in diabetic renal microvascular dysfunction is unclear. We tested the hypothesis that enhanced canonical Wnt signaling in renal afferent arterioles from diabetic mice increases reactive oxygen species (ROS) and contractions to endothelin-1 (ET-1). METHODS Streptozotocin-induced diabetes or control C57Bl/6 mice received vehicle or sulindac (40 mg·kg-1·day-1) to block Wnt signaling for 4 weeks. ET-1 contractions were measured by changes of afferent arteriolar diameter. Arteriolar H2O2, O2 -, protein expression and enzymatic activity were assessed using sensitive fluorescence probes, immunoblotting and colorimetric assay separately. RESULTS Compared to control, diabetic mouse afferent arteriole had increased O2- (+ 84%) and H2O2 (+ 91%) and enhanced responses to ET-1 at 10-8 mol·l-1 (-72±4% of versus -43±4%, P< 0.05) accompanied by reduced protein expressions and activities for catalase and superoxide dismutase 2 (SOD2). Arteriolar O2 - was increased further by ET-1 and contractions to ET-1 reduced by PEG-SOD in both groups whereas H2O2 unchanged by ET-1 and contractions were reduced by PEG-catalase selectively in diabetic mice. The Wnt signaling protein β-catenin was upregulated (3.3-fold decrease in p-β-catenin/β-catenin) while the glycogen synthase kinase-3β (GSK-3β) was downregulated (2.6-fold increase in p-GSK-3β/ GSK-3β) in preglomerular vessels of diabetic mice. Sulindac normalized the Wnt signaling proteins, arteriolar O2 -, H2O2 and ET-1 contractions while doubling microvascular catalase and SOD2 expression in diabetic mice. CONCLUSION Increased ROS, notably H2O2 contributes to enhanced afferent arteriolar responses to ET-1 in diabetes, which is closely associated with Wnt signaling. Antioxidant pharmacological strategies targeting Wnt signaling may improve vascular function in diabetic nephropathy.
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Affiliation(s)
- Suping Zhang
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qian Huang
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Department of Physiology, Quanzhou Medical College, Quanzhou, China
| | - Qiaoling Wang
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qin Wang
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyun Cao
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liang Zhao
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Nan Xu
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengbing Zhuge
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Mao
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaodong Fu
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Ruisheng Liu
- Department of Molecular Pharmacology & Physiology, University of South Florida College of Medicine, Tampa, Florida, USA
| | - Christopher S Wilcox
- Division of Nephrology and Hypertension, and Hypertension Center, Georgetown University, Washington, District of Columbia, USA
| | - Andreas Patzak
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lingli Li
- Division of Nephrology and Hypertension, and Hypertension Center, Georgetown University, Washington, District of Columbia, USA
| | - En Yin Lai
- Department of Physiology, and the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China,
- Division of Nephrology and Hypertension, and Hypertension Center, Georgetown University, Washington, District of Columbia, USA,
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Oliveira PAD, Dalton JAR, López-Cano M, Ricarte A, Morató X, Matheus FC, Cunha AS, Müller CE, Takahashi RN, Fernández-Dueñas V, Giraldo J, Prediger RD, Ciruela F. Angiotensin II type 1/adenosine A 2A receptor oligomers: a novel target for tardive dyskinesia. Sci Rep 2017; 7:1857. [PMID: 28500295 PMCID: PMC5431979 DOI: 10.1038/s41598-017-02037-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/06/2017] [Indexed: 01/28/2023] Open
Abstract
Tardive dyskinesia (TD) is a serious motor side effect that may appear after long-term treatment with neuroleptics and mostly mediated by dopamine D2 receptors (D2Rs). Striatal D2R functioning may be finely regulated by either adenosine A2A receptor (A2AR) or angiotensin receptor type 1 (AT1R) through putative receptor heteromers. Here, we examined whether A2AR and AT1R may oligomerize in the striatum to synergistically modulate dopaminergic transmission. First, by using bioluminescence resonance energy transfer, we demonstrated a physical AT1R-A2AR interaction in cultured cells. Interestingly, by protein-protein docking and molecular dynamics simulations, we described that a stable heterotetrameric interaction may exist between AT1R and A2AR bound to antagonists (i.e. losartan and istradefylline, respectively). Accordingly, we subsequently ascertained the existence of AT1R/A2AR heteromers in the striatum by proximity ligation in situ assay. Finally, we took advantage of a TD animal model, namely the reserpine-induced vacuous chewing movement (VCM), to evaluate a novel multimodal pharmacological TD treatment approach based on targeting the AT1R/A2AR complex. Thus, reserpinized mice were co-treated with sub-effective losartan and istradefylline doses, which prompted a synergistic reduction in VCM. Overall, our results demonstrated the existence of striatal AT1R/A2AR oligomers with potential usefulness for the therapeutic management of TD.
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Affiliation(s)
- Paulo A de Oliveira
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil
| | - James A R Dalton
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Network Biomedical Research Center on Mental Health (CIBERSAM), Bellaterra, Spain
| | - Marc López-Cano
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Adrià Ricarte
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Network Biomedical Research Center on Mental Health (CIBERSAM), Bellaterra, Spain
| | - Xavier Morató
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Filipe C Matheus
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil
| | - Andréia S Cunha
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | - Reinaldo N Takahashi
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Jesús Giraldo
- Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, Network Biomedical Research Center on Mental Health (CIBERSAM), Bellaterra, Spain.
| | - Rui D Prediger
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil. .,Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88049-900, Florianópolis, SC, Brazil.
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat, Spain. .,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.
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3
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Zhao L, Gao Y, Cao X, Gao D, Zhou S, Zhang S, Cai X, Han F, Wilcox CS, Li L, Lai EY. High-salt diet induces outward remodelling of efferent arterioles in mice with reduced renal mass. Acta Physiol (Oxf) 2017; 219:652-659. [PMID: 27454938 DOI: 10.1111/apha.12759] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 06/04/2016] [Accepted: 07/19/2016] [Indexed: 01/01/2023]
Abstract
AIM The glomerular filtration rate (GFR) falls progressively in chronic kidney disease (CKD) which is caused by a reduction in the number of functional nephrons. The dysfunctional nephron exhibits a lower glomerular capillary pressure that is induced by an unbalance between afferent and efferent arteriole. Therefore, we tested the hypothesis that oxidative stress induced by CKD differentially impairs the structure or function of efferent vs. afferent arterioles. METHODS C57BL/6 mice received sham operations (sham) or 5/6 nephrectomy (RRM) and three months of normal- or high-salt diet or tempol. GFR was assessed from the plasma inulin clearance, arteriolar remodelling from media/lumen area ratio, myogenic responses from changes in luminal diameter with increases in perfusion pressure and passive wall compliance from the wall stress/strain relationships. RESULTS Mice with RRM fed a high salt (vs. sham) had a lower GFR (553 ± 25 vs. 758 ± 36 μL min-1 g-1 kidney, P < 0.01) and a larger efferent arteriolar diameter (9.6 ± 0.8 vs. 7.4 ± 0.7 μm, P < 0.05) resulting in a lower media/lumen area ratio (1.4 ± 0.1 vs. 2.4 ± 0.2, P < 0.01). These alterations were corrected by tempol. The myogenic responses of efferent arterioles were about one-half that of afferent arterioles and were unaffected by RRM or salt. Passive wall compliance was reduced by high salt in both afferent and efferent arterioles. CONCLUSION A reduction in renal mass with a high-salt diet induces oxidative stress that leads to an outward eutrophic remodelling in efferent arterioles and reduced wall compliance in both afferent and efferent arterioles. This may contribute to the lower GFR in this model of CKD.
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Affiliation(s)
- L. Zhao
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - Y. Gao
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - X. Cao
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - D. Gao
- Department of Cardiology; The First Affiliated Hospital; Zhejiang University School of Medicine; Hangzhou China
| | - S. Zhou
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - S. Zhang
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - X. Cai
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
- Department of Basic Medicine; Honghe Health Vocational College; Mengzi China
| | - F. Han
- Institute of Pharmacology and Toxicology; College of Pharmaceutical Sciences; Zhejiang University; Hangzhou China
| | - C. S. Wilcox
- Division of Nephrology and Hypertension; Hypertension, Kidney and Vascular Health Center; Georgetown University; Washington DC USA
| | - L. Li
- Division of Nephrology and Hypertension; Hypertension, Kidney and Vascular Health Center; Georgetown University; Washington DC USA
| | - E. Y. Lai
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
- Division of Nephrology and Hypertension; Hypertension, Kidney and Vascular Health Center; Georgetown University; Washington DC USA
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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5
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Gao X, Peleli M, Zollbrecht C, Patzak A, Persson AEG, Carlström M. Adenosine A1 receptor-dependent and independent pathways in modulating renal vascular responses to angiotensin II. Acta Physiol (Oxf) 2015; 213:268-76. [PMID: 25251152 DOI: 10.1111/apha.12399] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/09/2014] [Accepted: 09/17/2014] [Indexed: 11/28/2022]
Abstract
AIM Renal afferent arterioles are the effector site for autoregulation of glomerular perfusion and filtration. There is synergistic interaction between angiotensin II (ANG II) and adenosine (Ado) in regulating arteriolar contraction; however, the mechanisms are not clear. In this context, this study investigated the contribution of A1 receptor-dependent and independent signalling mechanisms. METHODS Isolated perfused afferent arterioles from transgenic mice (A1 (+/+) and A1 (-/-) ) were used for vascular reactivity studies. Cultured vascular smooth muscle cells (VSMC) were used for phosphorylation studies of signalling proteins that induce arteriolar contraction. RESULTS Maximal arteriolar contraction to ANG II was attenuated in A1 (-/-) (22%) compared with A1 (+/+) (40%). Simultaneous incubation with low-dose ado (10(-8) mol L(-1) ) enhanced ANG II-induced contraction in A1 (+/+) (58%), but also in A1 (-/-) (42%). An ado transporter inhibitor (NBTI) abolished this synergistic effect in A1 (-/-) , but not in wild-type mice. Incubation with Ado + ANG II increased p38 phosphorylation in aortic VSMC from both genotypes, but treatment with NBTI only blocked phosphorylation in A1 (-/-) . Combination of ANG II + Ado also increased MLC phosphorylation in A1 (+/+) but not significantly in A1 (-/-) , and NBTI had no effects. In agreement, Ado + ANG II-induced phosphorylation of p38 and MLC in rat pre-glomerular VSMC was not affected by NBTI. However, during pharmacological inhibition of the A1 receptor simultaneous treatment with NBTI reduced phosphorylation of both p38 and MLC to control levels. CONCLUSION Interaction between ANG II and Ado in VSMC normally involves A1 receptor signalling, but this can be compensated by receptor independent actions that phosphorylate p38 MAPK and MLC.
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Affiliation(s)
- X. Gao
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - M. Peleli
- Department of Physiology & Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - C. Zollbrecht
- Department of Physiology & Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - A. Patzak
- Institute of Vegetative Physiology; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - A. E. G. Persson
- Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - M. Carlström
- Department of Physiology & Pharmacology; Karolinska Institutet; Stockholm Sweden
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Persson AEG, Lai EY, Gao X, Carlström M, Patzak A. Interactions between adenosine, angiotensin II and nitric oxide on the afferent arteriole influence sensitivity of the tubuloglomerular feedback. Front Physiol 2013; 4:187. [PMID: 23882224 PMCID: PMC3714451 DOI: 10.3389/fphys.2013.00187] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/28/2013] [Indexed: 11/13/2022] Open
Abstract
Adenosine, via activation of A1 receptors on the afferent arteriole (AA), mediates the tubuloglomerular feedback (TGF) mechanism. Angiotensin II and nitric oxide (NO) can modulate the sensitivity of the TGF mechanism. However, the interaction among these substances in regulating the TGF resetting phenomenon has been debated. Studies in isolated perfused AA have shown a biphasic response to accumulating doses of adenosine alone. In the nanomolar range adenosine has a weak contractile effect (7%), whereas vasodilatation is observed at high concentrations. However, a synergistic interaction between the contractile response by adenosine and that of angiotensin II has been demonstrated. Adenosine in low concentrations strongly enhances the response to angiotensin II. At the same time, angiotensin II in physiological concentrations increases significantly the contractile response to adenosine. Moreover, addition of a NO donor (spermine NONOate) to increase NO bioavailability abolished the contractile response from combined application of angiotensin II and adenosine. These mutual modulating effects of adenosine and angiotensin II, and the effect of NO on the response of AA can contribute to the resetting of the TGF sensitivity.
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Affiliation(s)
- A E G Persson
- Department of Medical Cell Biology, Uppsala University Uppsala, Sweden
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Patinha D, Fasching A, Pinho D, Albino-Teixeira A, Morato M, Palm F. Angiotensin II contributes to glomerular hyperfiltration in diabetic rats independently of adenosine type I receptors. Am J Physiol Renal Physiol 2013; 304:F614-22. [PMID: 23283998 DOI: 10.1152/ajprenal.00285.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Increased angiotensin II (ANG II) or adenosine can potentiate each other in the regulation of renal hemodynamics and tubular function. Diabetes is characterized by hyperfiltration, yet the roles of ANG II and adenosine receptors for controlling baseline renal blood flow (RBF) or tubular Na(+) handling in diabetes is presently unknown. Accordingly, the changes in their functions were investigated in control and 2-wk streptozotocin-diabetic rats after intrarenal infusion of the ANG II AT1 receptor antagonist candesartan, the adenosine A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), or their combination. Compared with controls, the baseline blood pressure, RBF, and renal vascular resistance (RVR) were similar in diabetics, whereas the glomerular filtration rate (GFR) and filtration fraction (FF) were increased. Candesartan, DPCPX, or the combination increased RBF and decreased RVR similarly in all groups. In controls, the GFR was increased by DPCPX, but in diabetics, it was decreased by candesartan. The FF was decreased by candesartan and DPCPX, independently. DPCPX caused the most pronounced increase in fractional Na(+) excretion in both controls and diabetics, whereas candesartan or the combination only affected fractional Li(+) excretion in diabetics. These results suggest that RBF, via a unifying mechanism, and tubular function are under strict tonic control of both ANG II and adenosine in both control and diabetic kidneys. Furthermore, increased vascular AT1 receptor activity is a contribution to diabetes-induced hyperfiltration independent of any effect of adenosine A1 receptors.
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Affiliation(s)
- Daniela Patinha
- Uppsala Univ., Dept. of Medical Cell Biology, Biomedical Center, Box 571, 751 23 Uppsala, Sweden
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8
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Li L, Lai EY, Huang Y, Eisner C, Mizel D, Wilcox CS, Schnermann J. Renal afferent arteriolar and tubuloglomerular feedback reactivity in mice with conditional deletions of adenosine 1 receptors. Am J Physiol Renal Physiol 2012; 303:F1166-75. [PMID: 22896040 DOI: 10.1152/ajprenal.00222.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adenosine 1 receptors (A1AR) have been shown in previous experiments to play a major role in the tubuloglomerular feedback (TGF) constrictor response of afferent arterioles (AA) to increased loop of Henle flow. Overexpression studies have pointed to a critical role of vascular A1AR, but it has remained unclear whether selective deletion of A1AR from smooth muscle cells is sufficient to abolish TGF responsiveness. To address this question, we have determined TGF response magnitude in mice in which vascular A1AR deletion was achieved using the loxP recombination approach with cre recombinase being controlled by a smooth muscle actin promoter (SmCre/A1ARff). Effective vascular deletion of A1AR was affirmed by absence of vasoconstrictor responses to adenosine or cyclohexyl adenosine (CHA) in microperfused AA. Elevation of loop of Henle flow from 0 to 30 nl/min caused a 22.1 ± 3.1% reduction of stop flow pressure in control mice and of 7.2 ± 1.5% in SmCre/A1ARff mice (P < 0.001). Maintenance of residual TGF activity despite absence of A1AR-mediated responses in AA suggests participation of extravascular A1AR in TGF. Support for this notion comes from the observation that deletion of A1ARff by nestin-driven cre causes an identical TGF response reduction (7.3 ± 2.4% in NestinCre/A1ARff vs. 20.3 ± 2.7% in controls), whereas AA responsiveness was reduced but not abolished. A1AR on AA smooth muscle cells are primarily responsible for TGF activation, but A1AR on extravascular cells, perhaps mesangial cells, appear to contribute to the TGF response.
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Affiliation(s)
- Lingli Li
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Drive-MSC 1370, Bethesda, MD 20892, USA
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Lee DL, Bell TD, Bhupatkar J, Solis G, Welch WJ. Adenosine A1-receptor knockout mice have a decreased blood pressure response to low-dose ANG II infusion. Am J Physiol Regul Integr Comp Physiol 2012; 303:R683-8. [PMID: 22874421 DOI: 10.1152/ajpregu.00116.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenosine, acting on A(1)-receptors (A(1)-AR) in the nephron, increases sodium reabsorption, and also increases renal vascular resistance (RVR), via A(1)-ARs in the afferent arteriole. ANG II increases blood pressure and RVR, and it stimulates adenosine release in the kidney. We tested the hypothesis that ANG II-infused hypertension is potentiated by A(1)-ARs' influence on Na(+) reabsorption. Mean arterial pressure (MAP) was measured by radiotelemetry in A(1)-AR knockout mice (KO) and their wild-type (WT) controls, before and during ANG II (400 ng·kg(-1)·min(-1)) infusion. Baseline MAP was not different between groups. ANG II increased MAP in both groups, but on day 12, MAP was lower in A(1)-AR KO mice (KO: 128 ± 3 vs. 139 ± 3 mmHg, P < 0.01). Heart rates were significantly different during days 11-14 of ANG II. Basal sodium excretion was not different (KO: 0.15 ± 0.03 vs. WT: 0.13 ± 0.04 mmol/day, not significant) but was higher in KO mice 12 days after ANG II despite a lower MAP (KO: 0.22 ± 0.03 vs. WT: 0.11 ± 0.02 mmol/day, P < 0.05). Phosphate excretion was also higher in A(1)-AR KO mice on day 12. Renal expression of the sodium-dependent phosphate transporter and the Na(+)/glucose cotransporter were lower in the KO mice during ANG II treatment, but the expression of the sodium hydrogen exchanger isoform 3 was not different. These results indicate that the increase in blood pressure seen in A(1)-AR KO mice is lower than that seen in WT mice but was increased by ANG II nonetheless. The presence of A(1)-ARs during a low dose of ANG II-infusion limits Na(+) and phosphate excretion. This study suggests that A(1)-AR antagonists might be an effective antihypertensive agent during ANG II and volume-dependent hypertension.
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Affiliation(s)
- Dexter L Lee
- Department of Physiology and Biophysics, Howard University, Washington, DC, USA
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Oppermann M, Qin Y, Lai EY, Eisner C, Li L, Huang Y, Mizel D, Fryc J, Wilcox CS, Briggs J, Schnermann J, Castrop H. Enhanced tubuloglomerular feedback in mice with vascular overexpression of A1 adenosine receptors. Am J Physiol Renal Physiol 2009; 297:F1256-64. [PMID: 19741017 DOI: 10.1152/ajprenal.00264.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adenosine 1 receptors (A1AR) in the kidney are expressed in the vasculature and the tubular system. Pharmacological inhibition or global genetic deletion of A1AR causes marked reductions or abolishment of tubuloglomerular feedback (TGF) responses. To assess the function of vascular A1AR in TGF, we generated transgenic mouse lines in which A1AR expression in smooth muscle was augmented by placing A1AR under the control of a 5.38-kb fragment of the rat smooth muscle alpha-actin promoter and first intron (12). Two founder lines with highest expression in the kidney [353 +/- 42 and 575 +/- 43% compared with the wild type (WT)] were used in the experiments. Enhanced expression of A1AR at the expected site in these lines was confirmed by augmented constrictor responses of isolated afferent arterioles to administration of the A1AR agonist N6-cyclohexyladenosine. Maximum TGF responses (0-30 nl/min flow step) were increased from 8.4 +/- 0.9 mmHg in WT (n = 21) to 14.2 +/- 0.7 mmHg in A1AR-transgene (tg) 4 (n = 22; P < 0.0001), and to 12.6 +/- 1.2 mmHg in A1AR-tg7 (n = 12; P < 0.02). Stepwise changes in perfusion flow caused greater numerical TGF responses in A1AR-tg than WT in all flow ranges with differences reaching levels of significance in the intermediate flow ranges of 7.5-10 and 10-15 nl/min. Proximal-distal single-nephron glomerular filtration rate (SNGFR) differences (free-flow micropuncture) were also increased in A1AR-tg, averaging 6.25 +/- 1.5 nl/min compared with 2.6 +/- 0.51 nl/min in WT (P = 0.034). Basal plasma renin concentrations as well as the suppression of renin secretion after volume expansion were similar in A1AR-tg and WT mice, suggesting lack of transgene expression in juxtaglomerular cells. These data indicate that A1AR expression in vascular smooth muscle cells is a critical component for TGF signaling and that changes in renal vascular A1AR expression may determine the magnitude of TGF responses.
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Affiliation(s)
- Mona Oppermann
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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