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Duan XP, Xiao Y, Su XT, Zheng JY, Gurley S, Emathinger J, Yang CL, McCormick J, Ellison DH, Lin DH, Wang WH. Role of Angiotensin II Type 1a Receptor (AT1aR) of Renal Tubules in Regulating Inwardly Rectifying Potassium Channels 4.2 (Kir4.2), Kir4.1, and Epithelial Na + Channel (ENaC). Hypertension 2024; 81:126-137. [PMID: 37909221 PMCID: PMC10842168 DOI: 10.1161/hypertensionaha.123.21389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/12/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND Kir4.2 and Kir4.1 play a role in regulating membrane transport in the proximal tubule (PT) and in the distal-convoluted-tubule (DCT), respectively. METHODS We generated kidney-tubule-specific-AT1aR-knockout (Ks-AT1aR-KO) mice to examine whether renal AT1aR regulates Kir4.2 and Kir4.1. RESULTS Ks-AT1aR-KO mice had a lower systolic blood pressure than Agtr1aflox/flox (control) mice. Ks-AT1aR-KO mice had a lower expression of NHE3 (Na+/H+-exchanger 3) and Kir4.2, a major Kir-channel in PT, than Agtr1aflox/flox mice. Whole-cell recording also demonstrated that the membrane potential in PT of Ks-AT1aR-KO mice was lesser negative than Agtr1aflox/flox mice. The expression of Kir4.1 and Kir5.1, Kir4.1/Kir5.1-mediated K+ currents of DCT and DCT membrane potential in Ks-AT1aR-KO mice, were similar to Agtr1aflox/flox mice. However, angiotensin II perfusion for 7 days hyperpolarized the membrane potential in PT and DCT of the control mice but not in Ks-AT1aR-KO mice, while angiotensin II perfusion did not change the expression of Kir4.1, Kir4.2, and Kir5.1. Deletion of AT1aR did not significantly affect the expression of αENaC (epithelial Na+ channel) and βENaC but increased cleaved γENaC expression. Patch-clamp experiments demonstrated that deletion of AT1aR increased amiloride-sensitive Na+-currents in the cortical-collecting duct but not in late-DCT. However, tertiapin-Q sensitive renal outer medullary potassium channel currents were similar in both genotypes. CONCLUSIONS AT1aR determines the baseline membrane potential of PT by controlling Kir4.2 expression/activity but AT1aR is not required for determining the baseline membrane potential of the DCT and Kir4.1/Kir5.1 activity/expression. However, AT1aR is required for angiotensin II-induced hyperpolarization of basolateral membrane of PT and DCT. Deletion of AT1aR had no effect on baseline renal outer medullary potassium channel activity but increased ENaC activity in the CCD.
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Affiliation(s)
- Xin-Peng Duan
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Yu Xiao
- Department of Physiology, Qiqihar Medical College, Heilongjiang, China
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Xiao-Tong Su
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Jun-Ya Zheng
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Susan Gurley
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | | | - Chao-Ling Yang
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - James McCormick
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - David H. Ellison
- Department of Medicine, Oregon Health & Science University, Portland, Oregon
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, NY
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, NY
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2
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Liu Y, Li L, Wang Z, Yang L. A comprehensive profiling of renin-angiotensin system in mouse and human plasma by a rapid quantitative analysis of 14 angiotensin peptides using ultrahigh-performance liquid chromatography with tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9637. [PMID: 37953545 DOI: 10.1002/rcm.9637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND The renin-angiotensin system produces a series of biologically active angiotensin (Ang) peptides. These Ang peptides are the major regulators of blood pressure and Na homeostasis, and play a critical role in maintaining cardiovascular and fluid homeostasis. The concentration of Ang peptides in the body is at trace levels, making their detection and quantification a challenge. In this study, a rapid and sensitive analytical method using mass spectrometry coupled with ultrahigh-performance liquid chromatography (UHPLC/MS) was developed to simultaneously quantify 14 Ang peptides. METHODS UHPLC/MS was employed to quantify 14 Ang peptides in mouse and human plasma. An HSS T3 column (2.1 × 100 mm, 1.8 μm) with an HSS T3 precolumn and triple-quadrupole mass spectrometer combined with an electrospray ionization source were utilized. Sample pretreatment involved a one-step protein precipitation using methanol. The total analysis time was within 7.5 min and the target peptides were detected in positive ion mode and quantified by selected reaction monitoring mode. RESULTS The method was validated for linearity, detection and quantification limits, precision, stability, recovery and matrix effect. The limits of detection of Ang II, Ang III, Ang-(1-7), Ang-(2-7), Ang-(3-7), Ang-(1-9), bradykinin, Asn1 and Val5 -Ang II are all less than 1 pg mL-1 , indicating high sensitivity. The intra-day and inter-day precision was within 15%, and the accuracy was between 85% and 115%. Meanwhile, the sample and reference solution were stable within 48 h, and the recovery and matrix effect met the quantitative requirements. CONCLUSIONS The method is currently reported to allow the largest number of Ang peptide species to be detected at one time. In addition, the proposed method offers a fast and reliable approach for comprehensive analysis of Ang metabolism in biological samples, facilitating research on the physiological and pathological states of cardiovascular, kidney and respiratory diseases.
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Affiliation(s)
- Yamin Liu
- MOE Key Laboratory of Standardization of Chinese Medicines and SATCM Key Laboratory of New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Linnan Li
- MOE Key Laboratory of Standardization of Chinese Medicines and SATCM Key Laboratory of New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhengtao Wang
- MOE Key Laboratory of Standardization of Chinese Medicines and SATCM Key Laboratory of New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Shanghai R&D Center for Standardization of Chinese Medicines, Shanghai, China
| | - Li Yang
- MOE Key Laboratory of Standardization of Chinese Medicines and SATCM Key Laboratory of New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Shanghai R&D Center for Standardization of Chinese Medicines, Shanghai, China
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3
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Cosarderelioglu C, Kreimer S, Plaza‐Rodriguez AI, Iglesias PA, Talbot CC, Siragy HM, Carey RM, Ubaida‐Mohien C, O'Rourke B, Ferrucci L, Bennett DA, Walston J, Abadir P. Decoding Angiotensin Receptors: TOMAHAQ-Based Detection and Quantification of Angiotensin Type-1 and Type-2 Receptors. J Am Heart Assoc 2023; 12:e030791. [PMID: 37681524 PMCID: PMC10547273 DOI: 10.1161/jaha.123.030791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/20/2023] [Indexed: 09/09/2023]
Abstract
Background The renin-angiotensin system plays a crucial role in human physiology, and its main hormone, angiotensin, activates 2 G-protein-coupled receptors, the angiotensin type-1 and type-2 receptors, in almost every organ. However, controversy exists about the location, distribution, and expression levels of these receptors. Concerns have been raised over the low sensitivity, low specificity, and large variability between lots of commercially available antibodies for angiotensin type-1 and type-2 receptors, which makes it difficult to reconciliate results of different studies. Here, we describe the first non-antibody-based sensitive and specific targeted quantitative mass spectrometry assay for angiotensin receptors. Methods and Results Using a technique that allows targeted analysis of multiple peptides across multiple samples in a single mass spectrometry analysis, known as TOMAHAQ (triggered by offset, multiplexed, accurate mass, high resolution, and absolute quantification), we have identified and validated specific human tryptic peptides that permit identification and quantification of angiotensin type-1 and type-2 receptors in biological samples. Several peptide sequences are conserved in rodents, making these mass spectrometry assays amenable to both preclinical and clinical studies. We have used this method to quantify angiotensin type-1 and type-2 receptors in postmortem frontal cortex samples of older adults (n=28) with Alzheimer dementia. We correlated levels of angiotensin receptors to biomarkers classically linked to renin-angiotensin system activation, including oxidative stress, inflammation, amyloid-β load, and paired helical filament-tau tangle burden. Conclusions These robust high-throughput assays will not only catalyze novel mechanistic studies in the angiotensin research field but may also help to identify patients with an unbalanced angiotensin receptor distribution who would benefit from angiotensin receptor blocker treatment.
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Affiliation(s)
- Caglar Cosarderelioglu
- Division of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMD
- Division of Geriatrics, Department of Internal MedicineAnkara University School of MedicineAnkaraTurkey
| | - Simion Kreimer
- The Mass Spectrometry and Proteomics FacilityJohns Hopkins University School of MedicineBaltimoreMD
| | | | - Pablo A. Iglesias
- Department of Electrical and Computer Engineering, Whiting School of EngineeringJohns Hopkins UniversityBaltimoreMD
| | - C. Conover Talbot
- Institute for Basic Biomedical Sciences, Johns Hopkins University School of MedicineBaltimoreMD
| | - Helmy M. Siragy
- Division of Endocrinology and Metabolism, Department of MedicineUniversity of VirginiaCharlottesvilleVA
| | - Robert M. Carey
- Division of Endocrinology and Metabolism, Department of MedicineUniversity of VirginiaCharlottesvilleVA
| | | | - Brian O'Rourke
- Division of Cardiology, Department of MedicineJohns Hopkins UniversityBaltimoreMD
| | - Luigi Ferrucci
- National Institute on Aging, National Institutes of HealthBaltimoreMD
| | - David A. Bennett
- Rush Alzheimer’s Disease CenterRush University Medical CenterChicagoIL
| | - Jeremy Walston
- Division of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMD
| | - Peter Abadir
- Division of Geriatric Medicine and GerontologyJohns Hopkins University School of MedicineBaltimoreMD
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Kukida M, Amioka N, Ye D, Chen H, Moorleghen JJ, Liang CL, Howatt DA, Katsumata Y, Yanagita M, Sawada H, Daugherty A, Lu HS. Manipulation of components of the renin angiotensin system in renal proximal tubules fails to alter atherosclerosis in hypercholesterolemic mice. Front Cardiovasc Med 2023; 10:1250234. [PMID: 37655218 PMCID: PMC10466789 DOI: 10.3389/fcvm.2023.1250234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/03/2023] [Indexed: 09/02/2023] Open
Abstract
Background and objective Whole body manipulation of the renin-angiotensin system (RAS) consistently exerts profound effects on experimental atherosclerosis development. A deficit in the literature has been a lack of attention to the effects of sex. Also, based on data with gene-deleted mice, the site of RAS activity that influences lesion formation is at an unknown distant location. Since angiotensin (AngII) concentrations are high in kidney and the major components of the RAS are present in renal proximal tubule cells (PTCs), this study evaluated the role of the RAS in PTCs in atherosclerosis development. Methods and results Mice with an LDL receptor -/- background were fed Western diet to induce hypercholesterolemia and atherosclerosis. We first demonstrated the role of AT1 receptor antagonism on atherosclerosis in both sexes. Losartan, an AngII type 1 (AT1) receptor blocker, had greater blood pressure-lowering effects in females than males, but equivalent effects between sexes in reducing atherosclerotic lesion size. To determine the roles of renal AT1a receptor and angiotensin-converting enzyme (ACE), either component was deleted in PTCs after weaning using a tamoxifen-inducible Cre expressed under the control of an Ndrg1 promoter. Despite profound deletion of AT1a receptor or ACE in PTCs, the absence of either protein did not influence development of atherosclerosis in either sex. Conversely, mice expressing human angiotensinogen and renin in PTCs or expressing human angiotensinogen in liver but human renin in PTCs did not change atherosclerotic lesion size in male mice. Conclusion Whole-body AT1R inhibition reduced atherosclerosis equivalently in both male and female mice; however, PTC-specific manipulation of the RAS components had no effects on hypercholesterolemia-induced atherosclerosis.
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Affiliation(s)
- Masayoshi Kukida
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Naofumi Amioka
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Dien Ye
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Hui Chen
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Jessica J. Moorleghen
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Ching-Ling Liang
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Deborah A. Howatt
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
| | - Yuriko Katsumata
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Biostatistics, University of Kentucky, Lexington, KY, United States
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan
| | - Hisashi Sawada
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
- Saha Aortic Center, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Alan Daugherty
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
- Saha Aortic Center, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
| | - Hong S. Lu
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, United States
- Saha Aortic Center, University of Kentucky, Lexington, KY, United States
- Department of Physiology, University of Kentucky, Lexington, KY, United States
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5
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DeLaney K, Jia D, Iyer L, Yu Z, Choi SB, Marvar PJ, Nemes P. Microanalysis of Brain Angiotensin Peptides Using Ultrasensitive Capillary Electrophoresis Trapped Ion Mobility Mass Spectrometry. Anal Chem 2022; 94:9018-9025. [PMID: 35696295 DOI: 10.1021/acs.analchem.2c01062] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While the role of the renin-angiotensin system (RAS) in peripheral circulation is well characterized, we still lack an in-depth understanding of its role within the brain. This knowledge gap is sustained by lacking technologies for trace-level angiotensin detection throughout tissues, such as the brain. To provide a bridging solution, we enhanced capillary electrophoresis (CE) nanoflow electrospray ionization (ESI) with large-volume sample stacking and employed trapped ion mobility time-of-flight (timsTOF) tandem HRMS detection. A dynamic pH junction helped stack approximately 10 times more of the sample than optimal using the field-amplified reference. In conjunction, the efficiency of ion generation was maximized by a cone-jet nanospray on a low sheath-flow tapered-tip nano-electrospray emitter. The platform provided additional peptide-dependent information, the collision cross section, to filter chemical noise and improve sequence identification and detection limits. The lower limit of detection reached sub-picomolar or ∼30 zmol (∼18,000 copies) level. All nine targeted angiotensin peptides in mouse tissue samples were detectable and quantifiable from the paraventricular nucleus (PVN) of the hypothalamus even after removal of circulatory blood components (perfusion). We anticipate CE-ESI with timsTOF HRMS to be broadly applicable for the ultrasensitive detection of brain peptidomes in pursuit of a better understanding of the brain.
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Affiliation(s)
- Kellen DeLaney
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
| | - Dashuang Jia
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
| | - Laxmi Iyer
- Department of Pharmacology & Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, D.C. 20037, United States
| | - Zhe Yu
- Department of Pharmacology & Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, D.C. 20037, United States
| | - Sam B Choi
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
| | - Paul J Marvar
- Department of Pharmacology & Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, D.C. 20037, United States
| | - Peter Nemes
- Department of Chemistry & Biochemistry, University of Maryland, 8051 Regents Drive, College Park, Maryland 20742, United States
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6
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Leite APDO, Li XC, Nwia SM, Hassan R, Zhuo JL. Angiotensin II and AT 1a Receptors in the Proximal Tubules of the Kidney: New Roles in Blood Pressure Control and Hypertension. Int J Mol Sci 2022; 23:2402. [PMID: 35269547 PMCID: PMC8910592 DOI: 10.3390/ijms23052402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023] Open
Abstract
Contrary to public perception, hypertension remains one of the most important public health problems in the United States, affecting 46% of adults with increased risk for heart attack, stroke, and kidney diseases. The mechanisms underlying poorly controlled hypertension remain incompletely understood. Recent development in the Cre/LoxP approach to study gain or loss of function of a particular gene has significantly helped advance our new insights into the role of proximal tubule angiotensin II (Ang II) and its AT1 (AT1a) receptors in basal blood pressure control and the development of Ang II-induced hypertension. This novel approach has provided us and others with an important tool to generate novel mouse models with proximal tubule-specific loss (deletion) or gain of the function (overexpression). The objective of this invited review article is to review and discuss recent findings using novel genetically modifying proximal tubule-specific mouse models. These new studies have consistently demonstrated that deletion of AT1 (AT1a) receptors or its direct downstream target Na+/H+ exchanger 3 (NHE3) selectively in the proximal tubules of the kidney lowers basal blood pressure, increases the pressure-natriuresis response, and induces natriuretic responses, whereas overexpression of an intracellular Ang II fusion protein or AT1 (AT1a) receptors selectively in the proximal tubules increases proximal tubule Na+ reabsorption, impairs the pressure-natriuresis response, and elevates blood pressure. Furthermore, the development of Ang II-induced hypertension by systemic Ang II infusion or by proximal tubule-specific overexpression of an intracellular Ang II fusion protein was attenuated in mutant mice with proximal tubule-specific deletion of AT1 (AT1a) receptors or NHE3. Thus, these recent studies provide evidence for and new insights into the important roles of intratubular Ang II via AT1 (AT1a) receptors and NHE3 in the proximal tubules in maintaining basal blood pressure homeostasis and the development of Ang II-induced hypertension.
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Affiliation(s)
- Ana Paula de Oliveira Leite
- Tulane Hypertension and Renal Center of Excellence, 1430 Tulane Avenue, New Orleans, LA 70112, USA; (A.P.d.O.L.); (X.C.L.); (S.M.N.); (R.H.)
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Xiao C. Li
- Tulane Hypertension and Renal Center of Excellence, 1430 Tulane Avenue, New Orleans, LA 70112, USA; (A.P.d.O.L.); (X.C.L.); (S.M.N.); (R.H.)
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Sarah M. Nwia
- Tulane Hypertension and Renal Center of Excellence, 1430 Tulane Avenue, New Orleans, LA 70112, USA; (A.P.d.O.L.); (X.C.L.); (S.M.N.); (R.H.)
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Rumana Hassan
- Tulane Hypertension and Renal Center of Excellence, 1430 Tulane Avenue, New Orleans, LA 70112, USA; (A.P.d.O.L.); (X.C.L.); (S.M.N.); (R.H.)
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Jia L. Zhuo
- Tulane Hypertension and Renal Center of Excellence, 1430 Tulane Avenue, New Orleans, LA 70112, USA; (A.P.d.O.L.); (X.C.L.); (S.M.N.); (R.H.)
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112, USA
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7
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Ni J, Yang F, Huang X, Meng J, Chen J, Bader M, Penninger JM, Fung E, Yu X, Lan H. Dual deficiency of angiotensin-converting enzyme-2 and Mas receptor enhances angiotensin II-induced hypertension and hypertensive nephropathy. J Cell Mol Med 2020; 24:13093-13103. [PMID: 32971570 PMCID: PMC7701568 DOI: 10.1111/jcmm.15914] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/03/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022] Open
Abstract
Angiotensin-converting enzyme-2 (ACE2) and Mas receptor are the major components of the ACE2/Ang 1-7/Mas axis and have been shown to play a protective role in hypertension and hypertensive nephropathy individually. However, the effects of dual deficiency of ACE2 and Mas (ACE2/Mas) on Ang II-induced hypertensive nephropathy remain unexplored, which was investigated in this study in a mouse model of hypertension induced in either ACE2 knockout (KO) or Mas KO mice and in double ACE2/Mas KO mice by subcutaneously chronic infusion of Ang II. Compared with wild-type (WT) animals, mice lacking either ACE2 or Mas significantly increased blood pressure over 7-28 days following a chronic Ang II infusion (P < .001), which was further exacerbated in double ACE2/Mas KO mice (P < .001). Furthermore, compared to a single ACE2 or Mas KO mice, mice lacking ACE2/Mas developed more severe renal injury including higher levels of serum creatinine and a further reduction in creatinine clearance, and progressive renal inflammation and fibrosis. Mechanistically, worsen hypertensive nephropathy in double ACE2/Mas KO mice was associated with markedly enhanced AT1-ERK1/2-Smad3 and NF-κB signalling, thereby promoting renal fibrosis and renal inflammation in the hypertensive kidney. In conclusion, ACE2 and Mas play an additive protective role in Ang II-induced hypertension and hypertensive nephropathy. Thus, restoring the ACE2/Ang1-7/Mas axis may represent a novel therapy for hypertension and hypertensive nephropathy.
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Affiliation(s)
- Jun Ni
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
- Department of Immunology and MicrobiologyShanghai Institute of ImmunologyShanghai Jiao Tong University School of MedicineShanghaiChina
| | - Fuye Yang
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
- Department of NephrologyThe Second Affiliated Hospital of Zhejiang University School of MedicineHangzhouChina
| | - Xiao‐Ru Huang
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
- Guangdong‐Hong Kong Joint Laboratory on Immunological and Genetic Kidney DiseasesGuangdong Provincial Key Laboratory Coronary Heart Disease PreventionGuangdong Cardiovascular InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Jinxiu Meng
- Guangdong‐Hong Kong Joint Laboratory on Immunological and Genetic Kidney DiseasesGuangdong Provincial Key Laboratory Coronary Heart Disease PreventionGuangdong Cardiovascular InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Jiaoyi Chen
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
| | - Michael Bader
- Max‐Delbrück Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany
| | - Josef M. Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of SciencesViennaAustria
| | - Erik Fung
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
| | - Xue‐Qing Yu
- Guangdong‐Hong Kong Joint Laboratory on Immunological and Genetic Kidney DiseasesGuangdong Provincial Key Laboratory Coronary Heart Disease PreventionGuangdong Cardiovascular InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhouChina
| | - Hui‐Yao Lan
- Department of Medicine & TherapeuticsLi Ka Shing Institute of Health SciencesLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong Kong SARChina
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8
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El Habhab A, Altamimy R, Abbas M, Kassem M, Amoura L, Qureshi AW, El Itawi H, Kreutter G, Khemais‐Benkhiat S, Zobairi F, Schini‐Kerth VB, Kessler L, Toti F. Significance of neutrophil microparticles in ischaemia-reperfusion: Pro-inflammatory effectors of endothelial senescence and vascular dysfunction. J Cell Mol Med 2020; 24:7266-7281. [PMID: 32520423 PMCID: PMC7339165 DOI: 10.1111/jcmm.15289] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 02/14/2020] [Accepted: 03/08/2020] [Indexed: 12/15/2022] Open
Abstract
Endothelial senescence is an emerging cause of vascular dysfunction. Because microparticles are effectors of endothelial inflammation and vascular injury after ischaemia-reperfusion, we examined leucocyte-derived microparticles of spleen origin as possible contributors. Microparticles were generated from primary rat splenocytes by either lipopolysaccharide or phorbol-myristate-acetate/calcium ionophore, under conditions mimicking innate and adaptive immune responses. Incubation of primary porcine coronary endothelial cells with either type of microparticles, but not with those from unstimulated splenocytes, leads to a similar threefold raise in senescence-associated β-galactosidase activity within 48 hours, indicating accelerated senescence, to endothelial oxidative stress, and a fivefold and threefold increase in p21 and p16 senescence markers after 24 hours. After 12-hour incubation, the endothelial-dependent relaxation of coronary artery rings was reduced by 50%, at distinct optimal microparticle concentration. In vitro, microparticles were pro-thrombotic by up-regulating the local angiotensin system, by prompting tissue factor activity and a secondary generation of pro-coagulant endothelial microparticles. They initiated an early pro-inflammatory response by inducing phosphorylation of NF-κB, MAP kinases and Akt after 1 hour, and up-regulated VCAM-1 and ICAM-1 at 24 hours. Accordingly, VCAM-1 and COX-2 were also up-regulated in the coronary artery endothelium and eNOS down-regulated. Lipopolysaccharide specifically favoured the shedding of neutrophil- and monocyte-derived microparticles. A 80% immuno-depletion of neutrophil microparticles reduced endothelial senescence by 55%, indicating a key role. Altogether, data suggest that microparticles from activated splenocytes prompt early pro-inflammatory, pro-coagulant and pro-senescent responses in endothelial cells through redox-sensitive pathways. The control of neutrophil shedding could preserve the endothelium at site of ischaemia-reperfusion-driven inflammation and delay its dysfunction.
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Affiliation(s)
- Ali El Habhab
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Raed Altamimy
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Malak Abbas
- UMR CNRS 7213Laboratory of Biophotonics and PharmacologyFaculty of PharmacyUniversity of StrasbourgIllkirch-GraffenstadenFrance
| | - Mohamad Kassem
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Lamia Amoura
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Abdul Wahid Qureshi
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Hanine El Itawi
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Guillaume Kreutter
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
| | - Sonia Khemais‐Benkhiat
- UMR CNRS 7213Laboratory of Biophotonics and PharmacologyFaculty of PharmacyUniversity of StrasbourgIllkirch-GraffenstadenFrance
| | - Fatiha Zobairi
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
- Faculty of MedicineFederation of Translational Medicine (FMTS)StrasbourgFrance
| | - Valérie B. Schini‐Kerth
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
- Faculty of PharmacyUniversity of StrasbourgIllkirch-GraffenstadenFrance
| | - Laurence Kessler
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
- Department of Diabetes and Nutrition EndocrinologyUniversity Hospital of StrasbourgStrasbourgFrance
- Faculty of MedicineFederation of Translational Medicine (FMTS)StrasbourgFrance
| | - Florence Toti
- INSERM (French National Institute of Health and Medical Research)UMR 1260Regenerative Nanomedicine (RNM)University of StrasbourgIllkirch-GraffenstadenFrance
- Faculty of PharmacyUniversity of StrasbourgIllkirch-GraffenstadenFrance
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9
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A microanalytical capillary electrophoresis mass spectrometry assay for quantifying angiotensin peptides in the brain. Anal Bioanal Chem 2019; 411:4661-4671. [PMID: 30953113 DOI: 10.1007/s00216-019-01771-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/23/2019] [Accepted: 03/08/2019] [Indexed: 01/04/2023]
Abstract
The renin-angiotensin system (RAS) of the brain produces a series of biologically active angiotensinogen-derived peptides involved in physiological homeostasis and pathophysiology of disease. Despite significant research efforts to date, a comprehensive understanding of brain RAS physiology is lacking. A significant challenge has been the limited set of bioanalytical assays capable of detecting angiotensin (Ang) peptides at physiologically low concentrations (2-15 fmol/g of wet tissue) and sufficient chemical specificity for unambiguous molecular identifications. Additionally, a complex brain anatomy calls for microanalysis of specific tissue regions, thus further taxing sensitivity requirements for identification and quantification in studies of the RAS. To fill this technology gap, we here developed a microanalytical assay by coupling a laboratory-built capillary electrophoresis (CE) nano-electrospray ionization (nano-ESI) platform to a high-resolution mass spectrometer (HRMS). Using parallel reaction monitoring, we demonstrated that this technology achieved confident identification and quantification of the Ang peptides at approx. 5 amol to 300 zmol sensitivity. This microanalytical assay revealed differential Ang peptide profiles between tissues that were micro-sampled from the subfornical organ and the paraventricular nucleus of the hypothalamus, important brain regions involved in thirst and water homeostasis and neuroendocrine regulation to stress. Microanalytical CE-nano-ESI-HRMS extends the analytical toolbox of neuroscience to help better understand the RAS.
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10
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Renin angiotensin system and its role in biomarkers and treatment in gliomas. J Neurooncol 2018; 138:1-15. [PMID: 29450812 DOI: 10.1007/s11060-018-2789-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 02/01/2018] [Indexed: 12/14/2022]
Abstract
Gliomas are the most common primary intrinsic tumor in the brain and are classified as low- or high-grade according to the World Health Organization (WHO). Patients with high-grade gliomas (HGG) who undergo surgical resection with adjuvant therapy have a mean overall survival of 15 months and 100% recurrence. The renin-angiotensin system (RAS), the primary regulator of cardiovascular circulation, exhibits local action and works as a paracrine system. In the context of this local regulation, the expression of RAS peptides and receptors has been detected in different kinds of tumors, including gliomas. The dysregulation of RAS components plays a significant role in the proliferation, angiogenesis, and invasion of these tumors, and therefore in their outcomes. The study and potential application of RAS peptides and receptors as biomarkers in gliomas could bring advantages against the limitations of current tumoral markers and should be considered in the future. The targeting of RAS components by RAS blockers has shown potential of being protective against cancer and improving immunotherapy. In gliomas, RAS blockers have shown a broad spectrum for beneficial effects and are being considered for use in treatment protocols. This review aims to summarize the background behind how RAS plays a role in gliomagenesis and explore the evidence that could lead to their use as biomarkers and treatment adjuvants.
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11
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Wu C, Daugherty A, Lu H. A Color Segmentation-Based Method to Quantify Atherosclerotic Lesion Compositions with Immunostaining. Methods Mol Biol 2017; 1614:21-30. [PMID: 28500592 DOI: 10.1007/978-1-4939-7030-8_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
There is an increasing recognition that atherosclerotic lesion composition, rather than size, is the determinant of acute events. Immunostaining is a commonly used method to characterize atherosclerotic lesion compositions. Here, we describe a color segmentation-based approach in HSI (hue, saturation, and intensity) color mode, which minimizes subjectivity and produces accurate and consistent quantifications of atherosclerotic lesion compositions.
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Affiliation(s)
- Congqing Wu
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, 40536, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Hong Lu
- Department of Physiology, University of Kentucky, Lexington, KY, USA.
- Saha Cardiovascular Research Center, University of Kentucky, BBSRB Room 249, 741 S. Limestone, BBSRB B249, Lexington, KY, 40536, USA.
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12
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Foster SR, Bräuner-Osborne H. Investigating Internalization and Intracellular Trafficking of GPCRs: New Techniques and Real-Time Experimental Approaches. Handb Exp Pharmacol 2017; 245:41-61. [PMID: 29018878 DOI: 10.1007/164_2017_57] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The ability to regulate the interaction between cells and their extracellular environment is essential for the maintenance of appropriate physiological function. For G protein-coupled receptors (GPCRs), this regulation occurs through multiple mechanisms that provide spatial and temporal control for signal transduction. One of the major mechanisms for GPCR regulation involves their endocytic trafficking, which serves to internalize the receptors from the plasma membrane and thereby attenuate G protein-dependent signaling. However, there is accumulating evidence to suggest that GPCRs can signal independently of G proteins, as well as from intracellular compartments including endosomes. It is in this context that receptor internalization and intracellular trafficking have attracted renewed interest within the GPCR field. In this chapter, we will review the current understanding and methodologies that have been used to investigate internalization and intracellular signaling of GPCRs, with a particular focus on emerging real-time techniques. These recent developments have improved our understanding of the complexities of GPCR internalization and intracellular signaling and suggest that the broader biological relevance and potential therapeutic implications of these processes remain to be explored.
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Affiliation(s)
- Simon R Foster
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
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13
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Poduri A, Rateri DL, Howatt DA, Balakrishnan A, Moorleghen JJ, Cassis LA, Daugherty A. Fibroblast Angiotensin II Type 1a Receptors Contribute to Angiotensin II-Induced Medial Hyperplasia in the Ascending Aorta. Arterioscler Thromb Vasc Biol 2015; 35:1995-2002. [PMID: 26160957 PMCID: PMC4552596 DOI: 10.1161/atvbaha.115.305995] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 06/29/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Angiotensin II (Ang II) infusion causes aortic medial thickening via stimulation of angiotensin II type 1a (AT1a) receptors. The purpose of this study was to determine the cellular loci of AT1a receptors that mediate this Ang II-induced aortic pathology. APPROACH AND RESULTS Saline or Ang II was infused into AT1a receptor floxed mice expressing Cre under control of cell-specific promoters. Initially, AT1a receptors were depleted in aortic smooth muscle cell and endothelium by expressing Cre under control of SM22 and Tie2 promoters, respectively. Deletion of AT1a receptors in either cell type had no effect on Ang II-induced medial thickening. To determine whether this effect was related to neural stimulation, AT1a receptors were depleted using an enolase 2-driven Cre. Depletion of AT1a receptors in neural cells attenuated Ang II-induced medial thickening of the ascending, but not descending aorta. Lineage tracking studies, using ROSA26-LacZ, demonstrated that enolase 2 was also expressed in adventitial cells adjacent to the region of attenuated thickening. To determine whether adventitial fibroblasts contributed to this attenuation, AT1a receptors in fibroblasts were depleted using S100A4 driven Cre. Similar to enolase 2-Cre, Ang II-induced medial thickening was attenuated in the ascending, but not the descending aorta. Lineage tracking demonstrated an increase of S100A4-LacZ positive cells in the media of the ascending region during Ang II infusion. CONCLUSIONS AT1a receptor depletion in fibroblasts attenuates Ang II-induced medial hyperplasia in the ascending aorta.
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MESH Headings
- Angiotensin II/toxicity
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/pathology
- Atherosclerosis/genetics
- Atherosclerosis/metabolism
- Atherosclerosis/prevention & control
- DNA/genetics
- Disease Models, Animal
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Gene Expression Regulation
- Genotype
- Hyperplasia/drug therapy
- Hyperplasia/genetics
- Hyperplasia/pathology
- Infusions, Intravenous
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- RNA, Messenger/genetics
- Receptor, Angiotensin, Type 1/administration & dosage
- Receptor, Angiotensin, Type 1/biosynthesis
- Receptor, Angiotensin, Type 1/genetics
- Tunica Media/drug effects
- Tunica Media/metabolism
- Tunica Media/pathology
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Affiliation(s)
- Aruna Poduri
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Debra L Rateri
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Deborah A Howatt
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Anju Balakrishnan
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Jessica J Moorleghen
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Lisa A Cassis
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington
| | - Alan Daugherty
- From the Saha Cardiovascular Research Center (A.P., D.L.R., D.A.H., A.B., J.J.M., A.D.) and Department of Molecular and Biomedical Pharmacology (L.A.C.), University of Kentucky, Lexington.
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14
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Grobe N, Di Fulvio M, Kashkari N, Chodavarapu H, Somineni HK, Singh R, Elased KM. Functional and molecular evidence for expression of the renin angiotensin system and ADAM17-mediated ACE2 shedding in COS7 cells. Am J Physiol Cell Physiol 2015; 308:C767-77. [PMID: 25740155 PMCID: PMC4420792 DOI: 10.1152/ajpcell.00247.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/24/2015] [Indexed: 12/29/2022]
Abstract
The renin angiotensin system (RAS) plays a vital role in the regulation of the cardiovascular and renal functions. COS7 is a robust and easily transfectable cell line derived from the kidney of the African green monkey, Cercopithecus aethiops. The aims of this study were to 1) demonstrate the presence of an endogenous and functional RAS in COS7, and 2) investigate the role of a disintegrin and metalloproteinase-17 (ADAM17) in the ectodomain shedding of angiotensin converting enzyme-2 (ACE2). Reverse transcription coupled to gene-specific polymerase chain reaction demonstrated expression of ACE, ACE2, angiotensin II type 1 receptor (AT1R), and renin at the transcript levels in total RNA cell extracts. Western blot and immunohistochemistry identified ACE (60 kDa), ACE2 (75 kDa), AT1R (43 kDa), renin (41 kDa), and ADAM17 (130 kDa) in COS7. At the functional level, a sensitive and selective mass spectrometric approach detected endogenous renin, ACE, and ACE2 activities. ANG-(1-7) formation (m/z 899) from the natural substrate ANG II (m/z 1,046) was detected in lysates and media. COS7 cells stably expressing shRNA constructs directed against endogenous ADAM17 showed reduced ACE2 shedding into the media. This is the first study demonstrating endogenous expression of the RAS and ADAM17 in the widely used COS7 cell line and its utility to study ectodomain shedding of ACE2 mediated by ADAM17 in vitro. The transfectable nature of this cell line makes it an attractive cell model for studying the molecular, functional, and pharmacological properties of the renal RAS.
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Affiliation(s)
- Nadja Grobe
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Mauricio Di Fulvio
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Nada Kashkari
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Harshita Chodavarapu
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Hari K Somineni
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Richa Singh
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
| | - Khalid M Elased
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, Ohio
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15
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Singh RR, Lankadeva YR, Denton KM, Moritz KM. Improvement in renal hemodynamics following combined angiotensin II infusion and AT1R blockade in aged female sheep following fetal unilateral nephrectomy. PLoS One 2013; 8:e68036. [PMID: 23840884 PMCID: PMC3698080 DOI: 10.1371/journal.pone.0068036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 05/24/2013] [Indexed: 01/13/2023] Open
Abstract
Renin-angiotensin system (RAS) is a powerful modulator of renal hemodynamic and fluid homeostasis. Up-regulation in components of intra-renal RAS occurs with ageing. Recently we reported that 2 year old uninephrectomised (uni-x) female sheep have low renin hypertension and reduced renal function. By 5 years of age, these uni-x sheep had augmented decrease in renal blood flow (RBF) compared to sham. We hypothesised that this decrease in RBF in 5 year old uni-x sheep was due to an up-regulation in components of the intra-renal RAS. In this study, renal responses to angiotensin II (AngII) infusion and AngII type 1 receptor (AT1R) blockade were examined in the same 5 year old sheep. We also administered AngII in the presence of losartan to increase AngII bioavailability to the AT2R in order to understand AT2R contribution to renal function in this model. Uni-x animals had significantly lower renal cortical content of renin, AngII (∼40%) and Ang 1-7 (∼60%) and reduced cortical expression of AT1R gene than sham animals. In response to both AngII infusion and AT1R blockade via losartan, renal hemodynamic responses and tubular sodium excretion were significantly attenuated in uni-x animals compared to sham. However, AngII infusion in the presence of losartan caused ∼33% increase in RBF in uni-x sheep compared to ∼14% in sham (P<0.05). This was associated with a significant decrease in renal vascular resistance in the uni-x animals (22% vs 15%, P<0.05) without any changes in systemic blood pressure. The present study shows that majority of the intra-renal RAS components are suppressed in this model of low renin hypertension. However, increasing the availability of AngII to AT2R by AT1R blockade improved renal blood flow in uni-x sheep. This suggests that manipulation of the AT2R maybe a potential therapeutic target for treatment of renal dysfunction associated with a congenital nephron deficit.
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Affiliation(s)
- Reetu R Singh
- School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia.
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