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Steckelings UM, Widdop RE, Sturrock ED, Lubbe L, Hussain T, Kaschina E, Unger T, Hallberg A, Carey RM, Sumners C. The Angiotensin AT 2 Receptor: From a Binding Site to a Novel Therapeutic Target. Pharmacol Rev 2022; 74:1051-1135. [PMID: 36180112 PMCID: PMC9553111 DOI: 10.1124/pharmrev.120.000281] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/19/2022] [Accepted: 06/27/2022] [Indexed: 11/22/2022] Open
Abstract
Discovered more than 30 years ago, the angiotensin AT2 receptor (AT2R) has evolved from a binding site with unknown function to a firmly established major effector within the protective arm of the renin-angiotensin system (RAS) and a target for new drugs in development. The AT2R represents an endogenous protective mechanism that can be manipulated in the majority of preclinical models to alleviate lung, renal, cardiovascular, metabolic, cutaneous, and neural diseases as well as cancer. This article is a comprehensive review summarizing our current knowledge of the AT2R, from its discovery to its position within the RAS and its overall functions. This is followed by an in-depth look at the characteristics of the AT2R, including its structure, intracellular signaling, homo- and heterodimerization, and expression. AT2R-selective ligands, from endogenous peptides to synthetic peptides and nonpeptide molecules that are used as research tools, are discussed. Finally, we summarize the known physiological roles of the AT2R and its abundant protective effects in multiple experimental disease models and expound on AT2R ligands that are undergoing development for clinical use. The present review highlights the controversial aspects and gaps in our knowledge of this receptor and illuminates future perspectives for AT2R research. SIGNIFICANCE STATEMENT: The angiotensin AT2 receptor (AT2R) is now regarded as a fully functional and important component of the renin-angiotensin system, with the potential of exerting protective actions in a variety of diseases. This review provides an in-depth view of the AT2R, which has progressed from being an enigma to becoming a therapeutic target.
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Affiliation(s)
- U Muscha Steckelings
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Robert E Widdop
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Edward D Sturrock
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Lizelle Lubbe
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Tahir Hussain
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Elena Kaschina
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Thomas Unger
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Anders Hallberg
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Robert M Carey
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
| | - Colin Sumners
- Institute of Molecular Medicine, Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark (U.M.S.); Cardiovascular Disease Program, Biomedicine Discovery Institute, Department of Pharmacology, Monash University, Clayton, Victoria, Australia (R.E.W.); Department of Integrative Biomedical Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Republic of South Africa (E.D.S., L.L.); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas (T.H.); Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Institute of Pharmacology, Cardiovascular-Metabolic-Renal (CMR) Research Center, DZHK (German Centre for Cardiovascular Research), Berlin, Germany (E.K.); CARIM - School for Cardiovascular Diseases, Maastricht University, The Netherlands (T.U.); Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala University, Uppsala, Sweden (A.H.); Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia (R.M.C.); and Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida (C.S.)
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2
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Kuczeriszka M, Dobrowolski L, Walkowska A, Baranowska I, Sitek JD, Kompanowska-Jezierska E. Role of Ang1-7 in renal haemodynamics and excretion in streptozotocin diabetic rats. Clin Exp Pharmacol Physiol 2021; 49:432-441. [PMID: 34870864 DOI: 10.1111/1440-1681.13618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 11/12/2021] [Accepted: 11/24/2021] [Indexed: 11/28/2022]
Abstract
The contribution of angiotensin (1-7) (Ang1-7) to control of extrarenal and renal function may be modified in diabetes. We investigated the effects of Ang1-7 supplementation on blood pressure, renal circulation and intrarenal reactivity (IVR) to vasoactive agents in normoglycaemic (NG) and streptozotocin diabetic rats (DM). In Sprague Dawley DM and NG rats, 3 weeks after streptozotocin (60 mg/kg i.p.) or solvent injection, Ang1-7 was administered (400 ng/min) over the next 2 weeks using subcutaneously implanted osmotic minipumps. For a period of 5 weeks, blood pressure (BP), 24 h water intake and diuresis were determined weekly. In anaesthetised rats, BP, renal total and cortical (CBF), outer (OMBF) and inner medullary (IMBF) perfusion and urine excretion were determined. To check IVR, a short-time infusion of acetylcholine or norepinephrine was randomly given to the renal artery. Unexpectedly, BP did not differ between NG and DM, and this was not modified by Ang-1-7 supplementation. Baseline IMBF was higher in NG vs. DM, and Ang1-7 treatment did not change it in NG but decreased it in DM. In the latter, Ang1-7 increased cortical IVR to vasoconstrictor and vasodilator stimuli. IMBF decrease after high acetylcholine dose seen in untreated NG was reverted to an increase in Ang1-7 treated rats. Irrespective of the glycaemia level, Ang1-7 did not modify BP. However, it impaired medullary circulation in DM, whereas in NG it rendered the medullary vasculature more sensitive to vasodilators. Possibly, the medullary hypoperfusion in DM was mediated by Ang1-7 activation of angiotensin AT-1 receptors which are upregulated by hyperglycaemia.
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Affiliation(s)
- Marta Kuczeriszka
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Leszek Dobrowolski
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Walkowska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Iwona Baranowska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Joanna D Sitek
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Elżbieta Kompanowska-Jezierska
- Department of Renal and Body Fluid Physiology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
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3
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Ma YP, Yang Y, Jiang SM, Liu L, Zhang Z, Wang YN, Zou GM, Li WG. Angiotensin II type 1 receptor blockers favorably affect renal angiotensin II and MAS receptor expression in patients with diabetic nephropathy. J Renin Angiotensin Aldosterone Syst 2021; 21:1470320320919607. [PMID: 32370637 PMCID: PMC7227143 DOI: 10.1177/1470320320919607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Introduction: The aims of this study were to assess the renal expression of angiotensin II type 1 receptor (AT1R), angiotensin II type 2 receptor (AT2R), and MAS receptor in human type 2 diabetic nephropathy (DN). Materials and methods: In total, 115 patients diagnosed with DN by renal biopsy were enrolled in this study. The protein expression levels of the AT1R, AT2R, and MAS receptors were assessed by immunohistochemistry. Results: The protein expression levels of AT1R, AT2R, and MAS receptor in the renal biopsy tissue were correlated with the pathologic classification of DN. Tubulointerstitial AT1R expression in patients of class IIb was significantly stronger than control samples (p < 0.05). Expression of AT2R and MAS receptors were highest with class IIb DN patients. When DN patients were treated with AT1R blocker (ARB), the expression of AT1R was downregulated (p < 0.05), and the MAS receptor was upregulated in tubular interstitial (p < 0.05). Conclusions: Our results directly observed that renal expression levels of AT1R increase during the early stages of DN, ARB reducing AT1R while increasing MAS receptor. Therefore, ARB should be used as soon as possible in patients with DN.
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Affiliation(s)
- Ye-Ping Ma
- Clinical Medicine School of China-Japan friendship, Peking Union Medical College, Beijing, China.,Department of Nephrology, Beijing Luhe Hospital, Capital Medical University, China
| | - Yue Yang
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Shi-Min Jiang
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Lin Liu
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Zheng Zhang
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Yi-Ning Wang
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Gu-Ming Zou
- Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
| | - Wen-Ge Li
- Clinical Medicine School of China-Japan friendship, Peking Union Medical College, Beijing, China.,Department of Nephrology, China-Japan Friendship Hospital, Beijing, China
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4
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Nasrallah R, Zimpelmann J, Robertson SJ, Ghossein J, Thibodeau JF, Kennedy CRJ, Gutsol A, Xiao F, Burger D, Burns KD, Hébert RL. Prostaglandin E2 receptor EP1 (PGE2/EP1) deletion promotes glomerular podocyte and endothelial cell injury in hypertensive TTRhRen mice. J Transl Med 2020; 100:414-425. [PMID: 31527829 DOI: 10.1038/s41374-019-0317-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/05/2019] [Accepted: 08/20/2019] [Indexed: 12/18/2022] Open
Abstract
Prostaglandin E2 receptor EP1 (PGE2/EP1) promotes diabetic renal injury, and EP1 receptor deletion improves hyperfiltration, albuminuria, and fibrosis. The role of EP1 receptors in hypertensive kidney disease (HKD) remains controversial. We examined the contribution of EP1 receptors to HKD. EP1 null (EP1-/-) mice were bred with hypertensive TTRhRen mice (Htn) to evaluate kidney function and injury at 24 weeks. EP1 deletion had no effect on elevation of systolic blood pressure in Htn mice (HtnEP1-/-) but resulted in pronounced albuminuria and reduced FITC-inulin clearance, compared with Htn or wild-type (WT) mice. Ultrastructural injury to podocytes and glomerular endothelium was prominent in HtnEP1-/- mice; including widened subendothelial space, subendothelial lucent zones and focal lifting of endothelium from basement membrane, with focal subendothelial cell debris. Cortex COX2 mRNA was increased by EP1 deletion. Glomerular EP3 mRNA was reduced by EP1 deletion, and EP4 by Htn and EP1 deletion. In WT mice, PGE2 increased chloride reabsorption via EP1 in isolated perfused thick ascending limb (TAL), but PGE2 or EP1 deletion did not affect vasopressin-mediated chloride reabsorption. In WT and Htn mouse inner medullary collecting duct (IMCD), PGE2 inhibited vasopressin-water transport, but not in EP1-/- or HtnEP1-/- mice. Overall, EP1 mediated TAL and IMCD transport in response to PGE2 is unaltered in Htn, and EP1 is protective in HKD.
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Affiliation(s)
- Rania Nasrallah
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada
| | - Joseph Zimpelmann
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada
| | | | - Jamie Ghossein
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada
| | | | - C R J Kennedy
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada.,Ottawa Hospital Research Institute, Kidney Research Centre, University of Ottawa, Ottawa, ON, Canada
| | - Alex Gutsol
- Ottawa Hospital Research Institute, Kidney Research Centre, University of Ottawa, Ottawa, ON, Canada
| | - Fengxia Xiao
- Ottawa Hospital Research Institute, Kidney Research Centre, University of Ottawa, Ottawa, ON, Canada
| | - Dylan Burger
- Ottawa Hospital Research Institute, Kidney Research Centre, University of Ottawa, Ottawa, ON, Canada
| | - Kevin D Burns
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada.,Ottawa Hospital Research Institute, Kidney Research Centre, University of Ottawa, Ottawa, ON, Canada
| | - Richard L Hébert
- Department of Cellular and Molecular Medicine, Faculty of Medicine, Kidney Research Centre, University of Ottawa, 451 Smyth Road, Room 2514, Ottawa, ON, Canada.
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Potential of Renin-Angiotensin-Aldosterone System Modulations in Diabetic Kidney Disease: Old Players to New Hope! Rev Physiol Biochem Pharmacol 2020; 179:31-71. [PMID: 32979084 DOI: 10.1007/112_2020_50] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Due to a tragic increase in the incidences of diabetes globally, diabetic kidney disease (DKD) has emerged as one of the leading causes of end-stage renal diseases (ESRD). Hyperglycaemia-mediated overactivation of the renin-angiotensin-aldosterone system (RAAS) is key to the development and progression of DKD. Consequently, RAAS inhibition by angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARBs) is the first-line therapy for the clinical management of DKD. However, numerous clinical and preclinical evidences suggested that RAAS inhibition can only halt the progression of the DKD to a certain extent, and they are inadequate to cure DKD completely. Recent studies have improved understanding of the complexity of the RAAS. It consists of two counter-regulatory arms, the deleterious pressor arm (ACE/angiotensin II/AT1 receptor axis) and the beneficial depressor arm (ACE2/angiotensin-(1-7)/Mas receptor axis). These advances have paved the way for the development of new therapies targeting the RAAS for better treatment of DKD. In this review, we aimed to summarise the involvement of the depressor arm of the RAAS in DKD. Moreover, in modern drug discovery and development, an advance approach is the bispecific therapeutics, targeting two independent signalling pathways. Here, we discuss available reports of these bispecific drugs involving the RAAS as well as propose potential treatments based on neurohormonal balance as credible therapeutic strategies for DKD.
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6
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Leite APO, Aragão DS, Nogueira MD, Pereira RO, Jara ZP, Fiorino P, Casarini DE, Farah V. Modulation of renin angiotensin system components by high glucose levels in the culture of collecting duct cells. J Cell Physiol 2019; 234:22809-22818. [DOI: 10.1002/jcp.28845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 11/11/2022]
Affiliation(s)
- A. P. O. Leite
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
- Laboratório de Renal, Cardiovascular e Fisiofarmacologia Metabólica, Centro de Ciência da Saúde e Biologia Universidade Presbiteriana Mackenzie São Paulo Brazil
| | - Danielle S. Aragão
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
| | - Marie D. Nogueira
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
| | - Renata O. Pereira
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
- Laboratório de Renal, Cardiovascular e Fisiofarmacologia Metabólica, Centro de Ciência da Saúde e Biologia Universidade Presbiteriana Mackenzie São Paulo Brazil
| | - Zaira P. Jara
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
- Department of Molecular Cardiology Lerner Research Institute—Cleveland Clinic Cleveland Ohio
| | - Patricia Fiorino
- Laboratório de Renal, Cardiovascular e Fisiofarmacologia Metabólica, Centro de Ciência da Saúde e Biologia Universidade Presbiteriana Mackenzie São Paulo Brazil
| | - Dulce E. Casarini
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
| | - Vera Farah
- Disciplina de Nefrologia, Departamento de Medicina, Escola Paulista de Medicina Universidade Federal de São Paulo São Paulo Brazil
- Laboratório de Renal, Cardiovascular e Fisiofarmacologia Metabólica, Centro de Ciência da Saúde e Biologia Universidade Presbiteriana Mackenzie São Paulo Brazil
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7
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Zhang J, Qu HY, Song J, Wei J, Jiang S, Wang L, Wang L, Buggs J, Liu R. Enhanced hemodynamic responses to angiotensin II in diabetes are associated with increased expression and activity of AT1 receptors in the afferent arteriole. Physiol Genomics 2017; 49:531-540. [PMID: 28842434 DOI: 10.1152/physiolgenomics.00025.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 12/28/2022] Open
Abstract
The prevalence of hypertension is about twofold higher in diabetic than in nondiabetic subjects. Hypertension aggravates the progression of diabetic complications, especially diabetic nephropathy. However, the mechanisms for the development of hypertension in diabetes have not been elucidated. We hypothesized that enhanced constrictive responsiveness of renal afferent arterioles (Af-Art) to angiotensin II (ANG II) mediated by ANG II type 1 (AT1) receptors contributes to the development of hypertension in diabetes. In response to an acute bolus intravenous injection of ANG II, alloxan-induced diabetic mice exhibited a higher mean arterial pressure (MAP) (119.1 ± 3.8 vs. 106.2 ± 3.5 mmHg) and a lower renal blood flow (0.25 ± 0.07 vs. 0.52 ± 0.14 ml/min) compared with nondiabetic mice. In response to chronic ANG II infusion, the MAP measured with telemetry increased by 55.8 ± 6.5 mmHg in diabetic mice, but only by 32.3 ± 3.8 mmHg in nondiabetic mice. The mRNA level of AT1 receptor increased by ~10-fold in isolated Af-Art of diabetic mice compared with nondiabetic mice, whereas ANG II type 2 (AT2) receptor expression did not change. The ANG II dose-response curve of the Af-Art was significantly enhanced in diabetic mice. Moreover, the AT1 receptor antagonist, losartan, blocked the ANG II-induced vasoconstriction in both diabetic mice and nondiabetic mice. In conclusion, we found enhanced expression of the AT1 receptor and exaggerated response to ANG II of the Af-Art in diabetes, which may contribute to the increased prevalence of hypertension in diabetes.
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Affiliation(s)
- Jie Zhang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Helena Y Qu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Jiangping Song
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Jin Wei
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Shan Jiang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Lei Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | - Liqing Wang
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
| | | | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, Tampa, Florida; and
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Garlic Attenuates Plasma and Kidney ACE-1 and AngII Modulations in Early Streptozotocin-Induced Diabetic Rats: Renal Clearance and Blood Pressure Implications. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:8142394. [PMID: 27293465 PMCID: PMC4887627 DOI: 10.1155/2016/8142394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/24/2016] [Indexed: 01/11/2023]
Abstract
Raw garlic aqueous extract (GE) has ameliorative actions on the renin-angiotensin system in type-1 diabetes mellitus (DM); however its effects on plasma and kidney angiotensin I converting enzyme type-1 (ACE-1) and angiotensin II (AngII) require further elucidation. This study investigated the effect of GE on plasma and kidney ACE-1 and AngII concentrations and in relation to systemic and renal clearance indicators significant to blood pressure (BP) homeostasis in early streptozotocin- (STZ-) induced type-1 DM. Normal rats (n = 10) received 0.5 mL normal saline (NR/NS), diabetic rats (n = 10) received 0.5 mL NS (DR/NS), and treated diabetic rats (n = 10) received 50 mg/0.1 mL/100 g body weight GE (DR/GE) as daily intraperitoneal injections for 8 weeks. Compared to NR/NS, DR/NS showed a significant increase in plasma ACE-1 and AngII and conversely a decrease in kidney ACE-1 and AngII. These changes were associated with an increase in BP and clearance functions. Alternatively and compared to DR/NS, DR/GE showed normalization or attenuation in plasma and kidney ACE-1 and AngII. These GE induced rectifications were associated with moderation in BP elevation and renal clearance functions. Garlic attenuates modulations in plasma and kidney ACE-1 and AngII, in addition to BP and renal clearance function in type-1 DM.
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9
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Abadir PM, Siragy HM. Angiotensin type 1 receptor mediates renal production and conversion of prostaglandins E2 to F2α in conscious diabetic rats. J Renin Angiotensin Aldosterone Syst 2015. [PMID: 26195268 DOI: 10.1177/1470320315592566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Previous studies demonstrated that stimulation of angiotensin subtype 1 receptor (AT1R) led to increased renal generation of prostaglandins E2 (PGE2) and renal inflammation. In turn, PGE2 increases AT1R activity. The conversion of PGE2 to the less active metabolite prostaglandin F2α (PGF2α) via 9-ketoreductase interrupts this feedback loop. The effects of diabetes on the interface between AT1R, PGE2 and PGF2α are not well established. We hypothesized that in diabetes, an aberrant AT1R activity enhances the biosynthesis of PGE2 and impairs the activity of PGE 9-ketoreductase, leading to accumulation of PGE2. MATERIALS AND METHODS Using microdialysis technique, we monitored renal interstitial fluid levels of angiotensin II (Ang II), PGE2 and PGF2α in control and AT1R blocker, valsartan, treated diabetic rats (N=8 each). We utilized the PGF2α to PGE2 ratio as indirect measure of PGE 9-ketoreductase activity. RESULTS Diabetes increased renal interstitial fluid levels of Ang II, PGE2 and PGF2α. PGF2α/PGE2 ratio increased by the third week, but declined by the sixth week of diabetes. Valsartan reduced PGE2 and PGF2α levels and increased Ang II and the conversion of PGE2 to PGF2α. CONCLUSION Our results suggest that in diabetes, AT1R increases PGE2 generation and reduces conversion of PGE2 to PGF2α with the progression of diabetes.
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Affiliation(s)
- Peter M Abadir
- Johns Hopkins University, Division of Geriatrics Medicine and Gerontology, Baltimore, USA
| | - Helmy M Siragy
- University of Virginia School of Medicine, Department of Medicine, Charlottesville, USA
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10
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Matavelli LC, Zatz R, Siragy HM. A nonpeptide angiotensin II type 2 receptor agonist prevents renal inflammation in early diabetes. J Cardiovasc Pharmacol 2015; 65:371-6. [PMID: 25590749 PMCID: PMC4390440 DOI: 10.1097/fjc.0000000000000207] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We hypothesized that direct AT2R stimulation improves albuminuria in diabetes by preventing renal inflammation and improving oxidative stress. Normoglycemic controls (NCs) and streptozotocin-induced diabetes Sprague-Dawley rats (DM) were treated for 4 weeks with vehicle (V) or the AT2R agonist Compound 21 (C21). At the end of study, we evaluated blood pressure, urinary albumin to creatinine ratio (UACR), renal interstitial fluid (RIF) levels of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), nitric oxide (NO), cGMP, and 8-isoprostane, and renal expression of TNF-α, IL-6, and AT2R. There were no significant differences in blood pressure between different treatments. DM rats demonstrated increased UACR, RIF TNF-α, IL-6 and 8-isoprostane, and messenger RNA (mRNA) for TNF-α and IL-6. DM rats also had reduced RIF NO and cGMP. C21 treatment of DM rats limited the increase in UACR, normalized RIF TNF-α, IL-6 and 8-isoprostane, and in mRNA for TNF-α and IL-6, and increased RIF NO and cGMP. In NC rats, C21 treatment did not change these parameters. AT2R mRNA and protein expressions increased in DM rats compared with NC but were not influenced by C21 treatment. We conclude that direct AT2R stimulation in diabetic rats improves diabetic albuminuria through the prevention of renal inflammation and improved production of NO and cGMP.
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Affiliation(s)
- Luis C. Matavelli
- Renal Division, Department of Medicine, School of Medicine, University of São Paulo, São Paulo, Brazil
- Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA
| | - Roberto Zatz
- Renal Division, Department of Medicine, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Helmy M. Siragy
- Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA
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11
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Abdo S, Zhang SL, Chan JSD. Reactive Oxygen Species and Nuclear Factor Erythroid 2-Related Factor 2 Activation in Diabetic Nephropathy: A Hidden Target. ACTA ACUST UNITED AC 2015. [PMID: 26213634 PMCID: PMC4511631 DOI: 10.4172/2155-6156.1000547] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hyperglycemia, oxidative stress and renin-angiotensin system (RAS) dysfunction have been implicated in diabetic nephropathy (DN) progression, but the underlying molecular mechanisms are far from being fully understood. In addition to the systemic RAS, the existence of a local intrarenal RAS in renal proximal tubular cells has been recognized. Angiotensinogen is the sole precursor of all angiotensins (Ang). Intrarenal reactive oxygen species (ROS) generation, Ang II level and RAS gene expression are up-regulated in diabetes, indicating that intrarenal ROS and RAS activation play an important role in DN. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is one of the major protective processes that occurs in response to intracellular oxidative stress. Nrf2 stimulates an array of antioxidant enzymes that convert excessive ROS to less reactive or less damaging forms. Recent studies have, however, revealed that Nrf2 activation might have other undesirable effects in diabetic animals and in diabetic patients with chronic kidney disease. This mini-review summarizes current knowledge of the relationship between ROS, Nrf2 and intra renal RAS activation in DN progression as well as possible novel target(s) for DN treatment.
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Affiliation(s)
- Shaaban Abdo
- Department of Medicine, University of Montreal and Research Center Hospital of QC, Canada
| | - Shao-Ling Zhang
- Department of Medicine, University of Montreal and Research Center Hospital of QC, Canada
| | - John S D Chan
- Department of Medicine, University of Montreal and Research Center Hospital of QC, Canada
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12
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Kobori H, Kamiyama M, Harrison-Bernard LM, Navar LG. Cardinal role of the intrarenal renin-angiotensin system in the pathogenesis of diabetic nephropathy. J Investig Med 2013. [PMID: 23266706 DOI: 10.231/jim.0b013e31827c28bb] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Diabetes mellitus is one of the most prevalent diseases and is associated with increased incidence of structural and functional derangements in the kidneys, eventually leading to end-stage renal disease in a significant fraction of afflicted individuals. The renoprotective effects of renin-angiotensin system (RAS) blockade have been established; however, the mechanistic pathways have not been fully elucidated. In this review article, the cardinal role of an activated RAS in the pathogenesis of diabetic nephropathy (DN) is discussed with a focus on 4 themes: (1) introduction to RAS cascade, (2) intrarenal RAS in diabetes, (3) clinical outcomes of RAS blockade in DN, and (4) potential of urinary angiotensinogen as an early biomarker of intrarenal RAS status in DN. This review article provides a mechanistic rational supporting the hypothesis that an activated intrarenal RAS contributes to the pathogenesis of DN and that urinary angiotensinogen levels provide an index of intrarenal RAS activity.
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Affiliation(s)
- Hiroyuki Kobori
- Department of Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center, New Orleans, LA, USA.
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13
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You H, Gao T, Cooper TK, Morris SM, Awad AS. Arginase inhibition mediates renal tissue protection in diabetic nephropathy by a nitric oxide synthase 3-dependent mechanism. Kidney Int 2013; 84:1189-97. [PMID: 23760286 PMCID: PMC3783645 DOI: 10.1038/ki.2013.215] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 04/01/2013] [Accepted: 04/04/2013] [Indexed: 01/15/2023]
Abstract
Recently we showed that pharmacological blockade or genetic deficiency of arginase-2 confers kidney protection in diabetic mouse models. Here we tested whether the protective effect of arginase inhibition is nitric oxide synthase-3 (eNOS)-dependent in diabetic nephropathy. Experiments were conducted in eNOS knockout and their wild type littermate mice using multiple low doses of vehicle or streptozotocin and treated with continuous subcutaneous infusion of vehicle or the arginase inhibitor S-(2-Boronoethyl)-L-cysteine by an osmotic pump. Inhibition of arginases for 6 weeks in diabetic wild type mice significantly attenuated albuminuria, the increase in plasma creatinine and blood urea nitrogen, histopathological changes, kidney fibronectin and TNF-α expression, kidney macrophage recruitment, and oxidative stress compared to vehicle-treated diabetic wild type mice. Arginase inhibition in diabetic eNOS knockout mice failed to affect any of these parameters but reduced kidney macrophage recruitment and kidney TNF-α expression compared to vehicle-treated diabetic eNOS knockout mice. Furthermore, diabetic wild type and eNOS knockout mice exhibited increased kidney arginase-2 protein, arginase activity and ornithine levels. Thus, arginase inhibition mediates renal tissue protection in diabetic nephropathy by an eNOS-dependent mechanism and has an eNOS-independent effect on kidney macrophage recruitment.
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Affiliation(s)
- Hanning You
- Division of Nephrology, Department of Medicine, Penn State University College of Medicine, Hershey, Pennsylvania, USA
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14
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Motawi TK, El-Maraghy SA, Senousy MA. Angiotensin-Converting Enzyme Inhibition and Angiotensin AT1 Receptor Blockade Downregulate Angiotensin-Converting Enzyme Expression and Attenuate Renal Injury in Streptozotocin-Induced Diabetic Rats. J Biochem Mol Toxicol 2013; 27:378-87. [DOI: 10.1002/jbt.21500] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/28/2013] [Accepted: 05/03/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Tarek K. Motawi
- Biochemistry Department; Faculty of Pharmacy; Cairo University; Cairo; Egypt
| | | | - Mahmoud A. Senousy
- Biochemistry Department; Faculty of Pharmacy; Cairo University; Cairo; Egypt
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15
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Kobori H, Kamiyama M, Harrison-Bernard LM, Navar LG. Cardinal Role of the Intrarenal Renin-Angiotensin System in the Pathogenesis of Diabetic Nephropathy. J Investig Med 2013; 61:256-264. [DOI: 10.2310/jim.0b013e31827c28bb] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Diabetes mellitus is one of the most prevalent diseases and is associated with increased incidence of structural and functional derangements in the kidneys, eventually leading to end-stage renal disease in a significant fraction of afflicted individuals. The renoprotective effects of renin-angiotensin system (RAS) blockade have been established; however, the mechanistic pathways have not been fully elucidated. In this review article, the cardinal role of an activated RAS in the pathogenesis of diabetic nephropathy (DN) is discussed with a focus on 4 themes: (1) introduction to RAS cascade, (2) intrarenal RAS in diabetes, (3) clinical outcomes of RAS blockade in DN, and (4) potential of urinary angiotensinogen as an early biomarker of intrarenal RAS status in DN. This review article provides a mechanistic rational supporting the hypothesis that an activated intrarenal RAS contributes to the pathogenesis of DN and that urinary angiotensinogen levels provide an index of intrarenal RAS activity.
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Affiliation(s)
- Hiroyuki Kobori
- *Department of Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center
| | - Masumi Kamiyama
- *Department of Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center
| | | | - L. Gabriel Navar
- *Department of Physiology, and Hypertension and Renal Center of Excellence, Tulane University Health Sciences Center
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16
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Jiang L, Teng GMK, Chan EYM, Au SWN, Wise H, Lee SST, Cheung WT. Impact of cell type and epitope tagging on heterologous expression of G protein-coupled receptor: a systematic study on angiotensin type II receptor. PLoS One 2012; 7:e47016. [PMID: 23056563 PMCID: PMC3466278 DOI: 10.1371/journal.pone.0047016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/11/2012] [Indexed: 12/19/2022] Open
Abstract
Despite heterologous expression of epitope-tagged GPCR is widely adopted for functional characterization, there is lacking of systematic analysis of the impact of expression host and epitope tag on GPCR expression. Angiotensin type II (AT2) receptor displays agonist-dependent and -independent activities, coupling to a spectrum of signaling molecules. However, consensus has not been reached on the subcellular distributions, signaling cascades and receptor-mediated actions. To examine the contributions of host cell and epitope tag on receptor expression and activity, epitope-tagged AT2 receptor variants were transiently or stably expressed in HEK293, CHO-K1 and PC12 cells. The epitope-tagged AT2 receptor variants were detected both on the cell membrane and in the perinuclear region. In transiently transfected HEK293 cells, Myc-AT2 existed predominantly as monomer. Additionally, a ladder of ubiquitinated AT2 receptor proteins was detected. By contrast, stably expressed epitope-tagged AT2 receptor variants existed as both monomer and high molecular weight complexes, and the latter was enriched in cell surface. Glycosylation promoted cell surface expression of Myc-AT2 but had no effect on AT2-GFP in HEK293 cells. In cells that stably expressed Myc-AT2, serum starvation induced apoptosis in CHO-K1 cells but not in HEK293 or PC12 cells. Instead, HEK293 and PC12 cells stably expressing Myc-AT2 exhibited partial cell cycle arrest with cells accumulating at G1 and S phases, respectively. Taken together, these results suggest that expression levels, subcellular distributions and ligand-independent constitutive activities of AT2 receptor were cell type-dependent while posttranslational processing of nascent AT2 receptor protein was modulated by epitope tag and mode of expression.
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Affiliation(s)
- Lili Jiang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Gladys M. K. Teng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Elaine Y. M. Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Shannon W. N. Au
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Helen Wise
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Susanna S. T. Lee
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- * E-mail: (WTC); (SL)
| | - Wing-Tai Cheung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- * E-mail: (WTC); (SL)
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17
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Kobori H, Urushihara M. Augmented intrarenal and urinary angiotensinogen in hypertension and chronic kidney disease. Pflugers Arch 2012; 465:3-12. [PMID: 22918624 DOI: 10.1007/s00424-012-1143-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 12/22/2022]
Abstract
Activated intrarenal renin-angiotensin system plays a cardinal role in the pathogenesis of hypertension and chronic kidney disease. Angiotensinogen is the only known substrate for renin, which is the rate-limiting enzyme of the renin-angiotensin system. Because the levels of angiotensinogen are close to the Michaelis-Menten constant values for renin, angiotensinogen levels as well as renin levels can control the renin-angiotensin system activity, and thus, upregulation of angiotensinogen leads to an increase in the angiotensin II levels and ultimately increases blood pressure. Recent studies using experimental animal models have documented the involvement of angiotensinogen in the intrarenal renin-angiotensin system activation and development of hypertension. Enhanced intrarenal angiotensinogen mRNA and/or protein levels were observed in experimental models of hypertension and chronic kidney disease, supporting the important roles of angiotensinogen in the development and the progression of hypertension and chronic kidney disease. Urinary excretion rates of angiotensinogen provide a specific index of the intrarenal renin-angiotensin system status in angiotensin II-infused rats. Also, a direct quantitative method has been developed recently to measure urinary angiotensinogen using human angiotensinogen enzyme-linked immunosorbent assay. These data prompted us to measure urinary angiotensinogen in patients with hypertension and chronic kidney disease, and investigate correlations with clinical parameters. This short article will focus on the role of the augmented intrarenal angiotensinogen in the pathophysiology of hypertension and chronic kidney disease. In addition, the potential of urinary angiotensinogen as a novel biomarker of the intrarenal renin-angiotensin system status in hypertension and chronic kidney disease will be also discussed.
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Affiliation(s)
- Hiroyuki Kobori
- Department of Physiology, Tulane University Health Sciences Center, 1430 Tulane Avenue, #SL39, New Orleans, LA 70112-2699, USA.
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18
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Garlic (Allium sativum) down-regulates the expression of angiotensin II AT1 receptor in adrenal and renal tissues of streptozotocin-induced diabetic rats. Inflammopharmacology 2012; 21:147-59. [DOI: 10.1007/s10787-012-0139-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 05/16/2012] [Indexed: 01/11/2023]
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19
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Yesudas R, Snyder R, Abbruscato T, Thekkumkara T. Functional role of sodium glucose transporter in high glucose-mediated angiotensin type 1 receptor downregulation in human proximal tubule cells. Am J Physiol Renal Physiol 2012; 303:F766-74. [PMID: 22647632 DOI: 10.1152/ajprenal.00651.2011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previously, we have demonstrated human angiotensin type 1 receptor (hAT(1)R) promoter architecture with regard to the effect of high glucose (25 mM)-mediated transcriptional repression in human proximal tubule epithelial cells (hPTEC; Thomas BE, Thekkumkara TJ. Mol Biol Cell 15: 4347-4355, 2004). In the present study, we investigated the role of glucose transporters in high glucose-mediated hAT(1)R repression in primary hPTEC. Cells were exposed to normal glucose (5.5 mM) and high glucose (25 mM), followed by determination of hyperglycemia-mediated changes in receptor expression and glucose transporter activity. Exposure of cells to high glucose resulted in downregulation of ANG II binding (4,034 ± 163.3 to 1,360 ± 154.3 dpm/mg protein) and hAT(1)R mRNA expression (reduced 60.6 ± 4.643%) at 48 h. Under similar conditions, we observed a significant increase in glucose uptake (influx) in cells exposed to hyperglycemia. Our data indicated that the magnitude of glucose influx is concentration and time dependent. In euglycemic cells, inhibiting sodium-glucose cotransporters (SGLTs) with phlorizin and facilitative glucose transporters (GLUTs) with phloretin decreased glucose influx by 28.57 ± 0.9123 and 54.33 ± 1.202%, respectively. However, inhibiting SGLTs in cells under hyperglycemic conditions decreased glucose influx by 53.67 ± 2.906%, while GLUT-mediated glucose uptake remained unaltered (57.67 ± 3.180%). Furthermore, pretreating cells with an SGLT inhibitor reversed high glucose-mediated downregulation of the hAT(1)R, suggesting an involvement of SGLT in high glucose-mediated hAT(1)R repression. Our results suggest that in hPTEC, hyperglycemia-induced hAT(1)R downregulation is largely mediated through SGLT-dependent glucose influx. As ANG II is an important modulator of hPTEC transcellular sodium reabsorption and function, glucose-mediated changes in hAT(1)R gene expression may participate in the pathogenesis of diabetic renal disease.
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Affiliation(s)
- Rekha Yesudas
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center,1300 Coulter Dr., Amarillo, TX 79106, USA
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20
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Velazquez-Roman JA, Villafaña S, Lopez Sanchez P, Fernandez-Vallín E, Bobadilla Lugo RA. Effect of Pregnancy and Diabetes on Vascular Receptors for Angiotensin II. Clin Exp Hypertens 2011; 33:167-73. [DOI: 10.3109/10641963.2010.531843] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Chawla T, Sharma D, Singh A. Role of the renin angiotensin system in diabetic nephropathy. World J Diabetes 2010; 1:141-5. [PMID: 21537441 PMCID: PMC3083897 DOI: 10.4239/wjd.v1.i5.141] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 09/01/2010] [Accepted: 09/08/2010] [Indexed: 02/05/2023] Open
Abstract
Diabetic nephropathy has been the cause of lot of morbidity and mortality in the diabetic population. The renin angiotensin system (RAS) is considered to be involved in most of the pathological processes that result in diabetic nephropathy. This system has various subsystems which contribute to the disease pathology. One of these involves angiotensin II (Ang II) which shows increased activity during diabetic nephropathy. This causes hypertrophy of various renal cells and has a pressor effect on arteriolar smooth muscle resulting in increased vascular pressure. Ang II also induces inflammation, apoptosis, cell growth, migration and differentiation. Monocyte chemoattractant protein-1 production responsible for renal fibrosis is also regulated by RAS. Polymorphism of angiotensin converting enzyme (ACE) and Angiotensinogen has been shown to have effects on RAS. Available treatment modalities have proven effective in controlling the progression of nephropathy. Various drugs (based on antagonism of RAS) are currently in the market and others are still under trial. Amongst the approved drugs, ACE inhibitors and angiotensin receptor blockers (ARBs) are widely used in clinical practice. ARBs are shown to be superior to ACE inhibitors in terms of reducing proteinuria but the combined role of ARBs with ACE inhibitors in diabetic nephropathy is under debate.
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Affiliation(s)
- Tanuj Chawla
- Tanuj Chawla, Department of Pharmacology, Lady Hardinge Medical College and Associated Hospitals, New Delhi 110001, India
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22
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Siragy HM. The angiotensin II type 2 receptor and the kidney. J Renin Angiotensin Aldosterone Syst 2009; 11:33-6. [PMID: 19861347 DOI: 10.1177/1470320309347786] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent knowledge demonstrated that the renin-angiotensin system (RAS) functions as a local renal paracrine system. All components of the RAS are present within the kidney and include angiotensinogen, renin, angiotensin I, angiotensin-converting enzymes, angiotensin II, the angiotensin II type 1 (AT(1)) receptor and the angiotensin II type 2 (AT(2)) receptor. Angiotensin II is the major effector hormone of the RAS and contributes to a variety of renal and cardiovascular physiologic and pathologic mechanisms through stimulation of AT(1) and AT(2) receptors. Angiotensin receptor blockers were developed based on the advanced knowledge of the AT(1) receptor contribution to development of a variety of kidney, vascular and cardiac diseases including but not limited to hypertension, diabetic nephropathy, heart failure, myocardial infarction and atherosclerosis. In contrast, knowledge concerning the role of the AT(2) receptor in health and disease is still emerging. The AT(2) receptor is believed to counterbalance the effects of the AT(1) receptor through influencing cellular differentiation, vasodilation, inhibition of cellular proliferation and hypertrophy, nitric oxide production and natriuresis. Thus, the pursuit of a specific AT(2) receptor agonist is a potentially fruitful area for combating renal and cardiovascular diseases. This review focuses on the role of the AT(2) receptor in the kidney.
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Affiliation(s)
- Helmy M Siragy
- Hypertension Centre, University of Virginia, Charlottesville, Virginia 22908, USA.
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23
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Mii A, Shimizu A, Masuda Y, Ishizaki M, Kawachi H, Iino Y, Katayama Y, Fukuda Y. Angiotensin II receptor blockade inhibits acute glomerular injuries with the alteration of receptor expression. J Transl Med 2009; 89:164-77. [PMID: 19139720 DOI: 10.1038/labinvest.2008.128] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Angiotensin II receptor blockade (ARB) suppresses the progression of chronic kidney disease. However, the renoprotective effect of ARB in the active phase of glomerulonephritis (GN) has not been evaluated in detail. We examined the alteration of angiotensin II receptors' expression and the action of ARB on acute glomerular injuries in GN. Thy-1 GN was induced in rats that were divided into three groups (n=7, in each group); high dose (3 mg/kg/day) or low dose (0.3 mg/kg/day) olmesartan (Thy-1 GN+HD- or LD-ARB group), and vehicle (Thy-1 GN group). Renal function and histopathology were assessed by week 2. In the Thy-1 GN group, diffuse mesangiolysis and focal aneurysmal ballooning developed by day 3. Marked mesangial proliferation and activation progressed with glomerular epithelial injury. We confirmed that both angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R) were expressed on glomerular endothelial, mesangial, epithelial cells, and macrophages, and increased 7 days after disease induction. However, ARB treatment caused a decrease in AT1R and a further increase in AT2R expression in glomeruli. ARB prevented capillary destruction and preserved eNOS expression after diffuse mesangiolysis. Mesangial proliferation and activation was suppressed markedly with low levels of PDGF-B expression. Glomerular desmin expression, which is a marker for injured glomerular epithelial cells, was diminished significantly with retained expression of nephrin and podoplanin. Glomerular macrophage infiltration was also inhibited. Proteinuria was suppressed significantly. Furthermore, these effects of ARB showed dose dependency. These results provide insights that ARB affects individual glomerular cells and macrophages through angiotensin II receptors, with the alteration of both AT1R and AT2R expressions, and leads to inhibition of the acute destructive and proliferative glomerular lesions in GN.
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Affiliation(s)
- Akiko Mii
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
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Hosojima M, Sato H, Yamamoto K, Kaseda R, Soma T, Kobayashi A, Suzuki A, Kabasawa H, Takeyama A, Ikuyama K, Iino N, Nishiyama A, Thekkumkara TJ, Takeda T, Suzuki Y, Gejyo F, Saito A. Regulation of megalin expression in cultured proximal tubule cells by angiotensin II type 1A receptor- and insulin-mediated signaling cross talk. Endocrinology 2009; 150:871-8. [PMID: 18927221 DOI: 10.1210/en.2008-0886] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Impairment of proximal tubular endocytosis of glomerular-filtered proteins including albumin results in the development of proteinuria/albuminuria in patients with chronic kidney disease. However, the mechanisms regulating the proximal tubular function are largely unknown. This study aimed to investigate the role of angiotensin II type 1A receptor (AT(1A)R)- and insulin-mediated signaling pathways in regulating the expression of megalin, a multiligand endocytic receptor in proximal tubule cells (PTCs). Opossum kidney PTC-derived OK cells that stably express rat AT(1A)R but are deficient in endogenous angiotensin II receptors (AT(1A)R-OK cells) were used for this study. Treatment of the cells with angiotensin II suppressed mRNA and protein expression of megalin at 3- and 24-h incubation time points, respectively. Cellular uptake and degradation of albumin and receptor-associated protein, megalin's endocytic ligands were suppressed 24 h after angiotensin II treatment. The AT(1A)R-mediated decrease in megalin expression was partially prevented by ERK inhibitors. Insulin competed with the AT(1A)R-mediated ERK activation and decrease in megalin expression. Inhibitors of phosphatidylinositol 3-kinase (PI3K), a major component of insulin signaling, also suppressed megalin expression, and activation of the insulin receptor substrate (IRS)/PI3K system was prevented by angiotensin II. Collectively the AT(1A)R-mediated ERK signaling is involved in suppressing megalin expression in the OK cell line, and insulin competes with this pathway. Conversely, the insulin-IRS/PI3K signaling, with which angiotensin II competes, tends to stimulate megalin expression. In conclusion, there is AT(1A)R- and insulin-mediated competitive signaling cross talk to regulate megalin expression in cultured PTCs.
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MESH Headings
- Angiotensin II/pharmacology
- Animals
- Cells, Cultured
- Endocytosis/drug effects
- Endocytosis/genetics
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Extracellular Signal-Regulated MAP Kinases/physiology
- Gene Expression Regulation/drug effects
- Insulin/pharmacology
- Insulin Receptor Substrate Proteins/metabolism
- Insulin Receptor Substrate Proteins/physiology
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Low Density Lipoprotein Receptor-Related Protein-2/genetics
- Low Density Lipoprotein Receptor-Related Protein-2/metabolism
- Models, Biological
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphatidylinositol 3-Kinases/physiology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Rats
- Receptor Cross-Talk/drug effects
- Receptor Cross-Talk/physiology
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/physiology
- Signal Transduction/drug effects
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Affiliation(s)
- Michihiro Hosojima
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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25
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Schulman IH, Raij L. The angiotensin II type 2 receptor: what is its clinical significance? Curr Hypertens Rep 2009; 10:188-93. [PMID: 18765088 DOI: 10.1007/s11906-008-0036-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Angiotensin (Ang) II exerts its important physiologic functions through two distinct receptor subtypes, the type 1 (AT1) and type 2 (AT2) receptors. AT1 and AT2 receptors have demonstrated counterregulatory interactions in the cardiovascular and renal systems. The cross-talk between AT1 and AT2 receptors has been suggested to participate in regulating blood pressure, cardiovascular growth, fibrosis, and remodeling, as well as renal blood flow, growth, fibrosis, and sodium excretion. The AT1 receptor is distributed ubiquitously and abundantly in adult tissues, whereas expression of the AT2 receptor is high in the fetus but low in adult tissues. However, mounting evidence indicates that AT2 receptor cardiovascular expression increases in response to injury and AT1 receptor blocker therapy. This article reviews recent experimental and clinical data elucidating the role of the AT2 receptor in cardiovascular and renal homeostasis.
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Affiliation(s)
- Ivonne Hernandez Schulman
- University of Miami Miller School of Medicine, Nephrology-Hypertension Section, Veterans Affairs Medical Center, 1201 Northwest 16 Street, Room A-1009, Miami, FL 33125, USA.
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Siddiqui AH, Ali Q, Hussain T. Protective role of angiotensin II subtype 2 receptor in blood pressure increase in obese Zucker rats. Hypertension 2008; 53:256-61. [PMID: 19114640 DOI: 10.1161/hypertensionaha.108.126086] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Earlier, we reported that there was an increase in angiotensin II type 2 (AT(2)) receptor expression in the renal proximal tubule, and selective activation of the AT(2) receptor by AT(2) agonist inhibits Na,K-ATPase activity in the proximal tubules and increases urinary Na excretion in obese Zucker rats. We hypothesized that the AT(2) receptor has a protective role against blood pressure increase in obese Zucker rats. To test this hypothesis, we treated obese Zucker rats with the AT(2) receptor antagonist PD123319 (PD; 30 microg/kg per minute) using osmotic pumps. Age-matched lean rats and vehicle-treated obese Zucker rats served as controls. On day 15 of the treatment with PD, arterial blood pressure was measured by cannulation of the left carotid artery under anesthesia. Control obese rats exhibited higher mean arterial pressure (122.0+/-3.4 mm Hg) compared with lean control rats (97.0+/-4.8 mm Hg). The PD treatment of obese rats raised mean arterial pressure further by 13 mm Hg. The plasma renin activity was significantly increased in the PD-treated obese compared with control-obese or lean rats. Western blot analysis revealed that the PD treatment in obese rats caused an approximately 3-fold increase in the renin expression in the kidney cortex but had no effect on the expression of the cortical angiotensin II type 1 and AT(2) receptors. The present study suggests that the renal AT(2) receptors provide a protective role against blood pressure increase in obese Zucker rats, and this protective effect, in part, could be because of the ability of the AT(2) receptors to keep the kidney renin expression low in obese rats.
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Affiliation(s)
- Athar H Siddiqui
- Heart and Kidney Institute, College of Pharmacy, University of Houston, Houston, TX 77204-5037, USA
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27
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Dharmani M, Mustafa MR, Achike FI, Sim MK. Involvement of AT(1) angiotensin receptors in the vasomodulatory effect of des-aspartate-angiotensin I in the rat renal vasculature. Peptides 2008; 29:1773-80. [PMID: 18603328 DOI: 10.1016/j.peptides.2008.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/13/2008] [Accepted: 05/20/2008] [Indexed: 10/22/2022]
Abstract
Angiotensin II is known to act primarily on the angiotensin AT(1) receptors to mediate its physiological and pathological actions. Des-aspartate-angiotensin I (DAA-I) is a bioactive angiotensin peptide and have been shown to have contrasting vascular actions to angiotensin II. Previous work in this laboratory has demonstrated an overwhelming vasodepressor modulation on angiotensin II-induced vasoconstriction by DAA-I. The present study investigated the involvement of the AT(1) receptor in the actions of DAA-I on angiotensin II-induced vascular actions in the renal vasculature of normotensive Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and streptozotocin (STZ)-induced diabetic rats. The findings revealed that the angiotensin receptor in rat kidney homogenate was mainly of the AT(1) subtype. The AT(1) receptor density was significantly higher in the kidney of the SHR. The increase in AT(1) receptor density was also confirmed by RT-PCR and Western blot analysis. In contrast, AT(1) receptor density was significantly reduced in the kidney of the streptozotocin-induced diabetic rat. Perfusion with 10(-9)M DAA-I reduced the AT(1) receptor density in the kidneys of WKY and SHR rats suggesting that the previously observed vasodepressor modulation of the nonapeptide could be due to down-regulation or internalization of AT(1) receptors. RT-PCR and Western blot analysis showed no significant changes in the content of AT(1) receptor mRNA and protein. This supports the suggestion that DAA-I causes internalization of AT(1) receptors. In the streptozotocin-induced diabetic rat, no significant changes in renal AT(1) receptor density and expression were seen when its kidneys were similarly perfused with DAA-I.
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Affiliation(s)
- M Dharmani
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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28
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Abdel-Rahman EM, Abadir PM, Siragy HM. Regulation of renal 12(S)-hydroxyeicosatetraenoic acid in diabetes by angiotensin AT1 and AT2 receptors. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1473-8. [PMID: 18799632 DOI: 10.1152/ajpregu.90699.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Diabetes is associated with increased production of 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE]. The mechanisms involved in this process remain unclear. We hypothesized that hyperglycemia and angiotensin II (ANG II) regulate renal 12(S)-HETE production via a balance between angiotensin AT(1) and AT(2) receptors activities. Using a microdialysis technique, renal interstitial fluid (RIF) levels of ANG II and 12(S)-HETE were monitored in normal control and streptozotocin-induced diabetic rats at baseline and then weekly thereafter for 12 wk. In a second group of normal and diabetic rats, 3 wk after development of diabetes, we monitored RIF 12(S)-HETE levels in response to acute AT(1) receptor blockade with valsartan or AT(2) receptor blockade with PD123319 individually or combined. Two weeks after induction of diabetes there was a 404% increase in ANG II (P < 0.05), a 149% increase in 12S-HETE (P < 0.05), and a 649% increase in urinary albumin excretion (P < 0.05). These levels remained elevated throughout the study. PD123319 given alone had no effect on 12(S)-HETE. Valsartan decreased 12(S)-HETE by 61.6% (P < 0.0001), a response that was abrogated when PD123319 was given with valsartan. These data demonstrate that hyperglycemia increases renal ANG II and 12(S)-HETE levels. The increase in 12(S)-HETE is mediated via AT(1) receptor. The attenuation of the effects of AT(1) receptor blockade by PD123319 suggests that AT(2) receptor contributes to the downregulation of renal 12(S)-HETE production.
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Affiliation(s)
- Emaad M Abdel-Rahman
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908-1409, USA
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29
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Jones ES, Vinh A, McCarthy CA, Gaspari TA, Widdop RE. AT2 receptors: functional relevance in cardiovascular disease. Pharmacol Ther 2008; 120:292-316. [PMID: 18804122 PMCID: PMC7112668 DOI: 10.1016/j.pharmthera.2008.08.009] [Citation(s) in RCA: 196] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 08/07/2008] [Indexed: 12/24/2022]
Abstract
The renin angiotensin system (RAS) is intricately involved in normal cardiovascular homeostasis. Excessive stimulation by the octapeptide angiotensin II contributes to a range of cardiovascular pathologies and diseases via angiotensin type 1 receptor (AT1R) activation. On the other hand, tElsevier Inc.he angiotensin type 2 receptor (AT2R) is thought to counter-regulate AT1R function. In this review, we describe the enhanced expression and function of AT2R in various cardiovascular disease settings. In addition, we illustrate that the RAS consists of a family of angiotensin peptides that exert cardiovascular effects that are often distinct from those of Ang II. During cardiovascular disease, there is likely to be an increased functional importance of AT2R, stimulated by Ang II, or even shorter angiotensin peptide fragments, to limit AT1R-mediated overactivity and cardiovascular pathologies.
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Affiliation(s)
- Emma S Jones
- Department of Pharmacology, Monash University, Clayton, Victoria 3800, Australia
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30
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Shao Y, He M, Zhou L, Yao T, Huang Y, Lu LM. Chronic angiotensin (1-7) injection accelerates STZ-induced diabetic renal injury. Acta Pharmacol Sin 2008; 29:829-37. [PMID: 18565281 DOI: 10.1111/j.1745-7254.2008.00812.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
AIM The renin-angiotensin system (RAS) plays a critical role in blood pressure control and body fluid and electrolyte homeostasis. In the past few years, angiotensin (Ang) (1-7) has been reported to counteract the effects of Ang II and was even considered as a new therapeutical target in RAS. The present study aimed to investigate the effect of Ang (1-7) administration on a diabetic animal model and the modulation on local RAS. METHODS Streptozotocin (STZ) injection-induced diabetic rats were used in the experiment. The animals were divided into 3 groups: (1) control; (2) STZ-induced diabetes; and (3) STZ-induced diabetes with chronic Ang (1-7) treatment [D+Ang(1-7)]. In the D+Ang(1-7) group, a dose of 25 microg x kg(-1) x h(-1) of Ang (1-7) was continually injected through the jugular vein by embedding miniosmotic pump for 6 weeks. Plasma glucose, ratio of kidney to body weight, and 24 h urine protein and serum creatinine were monitored by conventional measurement. Plasma and renal Ang II levels were measured by radioimmunoassay. Ang-converting enzyme (ACE), ACE2, Ang II type 1 (AT1) receptor, Ang II type 2 (AT2) receptor, Ang (1-7) Mas receptor, and TGF- beta1 mRNA levels were measured by real time PCR; ACE, ACE2, and TGF- beta1 protein levels were analyzed by Western blotting. RESULTS The renal function of diabetic rats was significantly retrogressed when compared with that of control rats. After the treatment by constant Ang (1-7) vein injection for 6 weeks, renal function was found to be even worse than diabetic rats, and both TGF-beta1 mRNA and protein levels were elevated in the D+Ang(1-7) group compared with the diabetic rats. The real-time PCR result also showed an increase in ACE mRNA expression and decrease in ACE2 mRNA level in the D+Ang(1-7) group when compared with diabetic rats. The number of AT1 receptors increased in the Ang (1-7)-injected group, while the number of AT2 and Mas receptors decreased. CONCLUSION Exogenous Ang (1-7) injection did not ameliorate STZinduced diabetic rat renal injury; on the contrary, it accelerated the progressive diabetic nephropathies.
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Affiliation(s)
- Ying Shao
- Department of Physiology and Pathophysiology, Shanghai Medical College, Fudan University, Shanghai 200032, China
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31
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Siragy HM, Huang J. Renal (pro)renin receptor upregulation in diabetic rats through enhanced angiotensin AT1 receptor and NADPH oxidase activity. Exp Physiol 2008; 93:709-14. [PMID: 18192338 DOI: 10.1113/expphysiol.2007.040550] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recent studies have demonstrated the presence of the (pro)renin receptor (PRR) in the glomerular mesangium and the subendothelial layer of the renal arteries. We hypothesized that diabetes upregulates PRR expression through enhanced angiotensin subtype 1 (AT1) receptor-NADPH oxidase cascade activity. Using real-time polymerase chain reaction, Western blot analysis and immunostaining, we studied renal localization of the PRR in the streptozotocin-induced diabetic rat model and in response to 1 week of treatment with the AT1 receptor blocker valsartan (10 mg kg(-1) day(-1)), the angiotensin AT2 receptor blocker PD123319 (0.5 mg kg(-1) day(-1)) or the NADPH oxidase inhibitor diphenylene iodonium (DPI; 0.5 mg kg(-1) day(-1)) 6 weeks post-induction of diabetes. Both PRR mRNA and protein were expressed constitutively in the kidneys of normal rat renal cortex and medulla, mainly in glomerular mesangium, proximal, distal and collecting tubules. Compared with normal rats (100%), diabetic rats demonstrated an increase in renal PRR mRNA (184%), protein (228%) and immunostaining. Valsartan and DPI prevented the increase in the PRR mRNA (106 and 126%, respectively), protein (97 and 140%, respectively) and immunostaining that was seen in the kidneys of diabetic rats. The AT2 blocker PD123319 did not have significant effects on PRR mRNA (157%) or protein expression (200%) in the kidneys of diabetic rats. These results demonstrate that the PRR is constitutively expressed in renal glomeruli and tubules. Expression of the PRR is upregulated in diabetes via enhancement of AT1 receptor-NADPH oxidase activity.
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Affiliation(s)
- Helmy M Siragy
- Department of Medicine, University of Virginia Health System, Charlottesville, VA 22908-1409, USA.
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32
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Mathur G, Noronha B, Rodrigues E, Davis G. The role of angiotensin II type 1 receptor blockers in the prevention and management of diabetes mellitus. Diabetes Obes Metab 2007; 9:617-29. [PMID: 17697055 DOI: 10.1111/j.1463-1326.2006.00644.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Angiotensin II Receptor blockers (ARBs) are an important addition to the current range of medications available for treating a wide spectrum of diseases including cardiovascular diseases. Coronary heart disease (CHD) is the most common cause of death in the United Kingdom and worldwide. More importantly, the presence of the metabolic syndrome and the likelihood of diabetes mellitus taking on epidemic proportions in the years to come all threaten to maintain the mortality rate due to CHD. This review article focuses on the clinical studies that have helped define the trends in the usage of these agents in the prevention and treatment of diabetes mellitus and its complications and also explores possible mechanisms of action and future developments.
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Affiliation(s)
- G Mathur
- Cardiovascular Research Group, Aintree Cardiac Centre, University Hospital Aintree, Liverpool, UK
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33
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Ronchi FA, Irigoyen MC, Casarini DE. Association of somatic and N-domain angiotensin-converting enzymes from Wistar rat tissue with renal dysfunction in diabetes mellitus. J Renin Angiotensin Aldosterone Syst 2007; 8:34-41. [PMID: 17487824 DOI: 10.3317/jraas.2007.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Diabetes mellitus (DM) is characterised by alterations in the intrarenal renin-angiotensin system (RAS). Insulin treatment may reverse these changes by an unknown mechanism. We aimed to verify the association between somatic ACE with 136 kDa (sACE) and N-domain ACE with 69 kDa (nACE) from Wistar (W) rat tissue with DM. Three groups were studied: control (CT), insulin treated diabetic (DT) and untreated (D). ACE activity was determined using Hippuryl-His-Leu and Z-Phe-His-Leu as substrates. In D group, urine ACE activity increased for both substrates when compared with CT and DT, despite the decreased activity of renal tissues. Immunostaining of renal tissue demonstrated that ACE is more strongly expressed in the proximal-tubule of D than in the same nephron portion in the other groups. Angiotensin (Ang) 1-7 and Ang II are less expressed in DT group when compared with CT and D. Ang II levels decreased in the D and DT groups showed when compared to the control. Ang 1-7 was detected in all studied groups with low levels in DT. The modulation of angiotensin peptides suggests that sACE, nACE, ACE 2 and NEP could have important functions in renal RAS regulation through a counter-regulatory mechanism to protect the kidney in diabetes mellitus.
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Igarashi M, Hirata A, Nozaki H, Kadomoto-Antsuki Y, Tominaga M. Role of angiotensin II type-1 and type-2 receptors on vascular smooth muscle cell growth and glucose metabolism in diabetic rats. Diabetes Res Clin Pract 2007; 75:267-77. [PMID: 16934905 DOI: 10.1016/j.diabres.2006.06.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Revised: 06/07/2006] [Accepted: 06/26/2006] [Indexed: 12/31/2022]
Abstract
This study investigates the mechanisms whereby angiotensin II (Ang II) signaling contributes to cell growth and glucose metabolism in cultured vascular smooth muscle cells (VSMCs) from male Wistar fatty rats (WF) and their littermates (Wistar lean rats, WL). The levels of the medial outgrowth rate of VSMCs and Ang II type-1 receptors (AT1R) in aortae from WF were more enhanced than those in aortae from WL, but the level of Ang II type-2 receptors (AT2R) was not different. A mixture of insulin and Ang II additively increased the values of [(3)H]-thymidine incorporation in WF and WL, which was inhibited by olmesartan, an AT1 receptor blockade (ARB), but not by PD123,319, an AT2 receptor blockade. Similarly, insulin and Ang II phosphorylated extracellular-regulated protein kinase 1/2, retinoblastoma tumor suppressor protein, and cyclic AMP response element binding protein, and these levels were higher in WF than in WL. In contrast, the phosphorylation was suppressed by olmesartan but not PD123,319. Insulin-stimulated Akt phosphorylation and 2-deoxy-d-glucose uptake in WF were significantly reduced by Ang II, and the reduction was ameliorated by olmesartan but not PD123,319. Differently from the result of Akt, the phosphorylation of the insulin-stimulated insulin receptor beta-subunit was not affected by Ang II, olmesartan, or PD123,319. However, the phosphorylation of insulin-stimulated insulin-related substrate (IRS)-1 was suppressed by Ang II, and the suppression was ameliorated by olmesartan, but not PD123,319, in both WF and WL. In contrast, the phosphorylation of IRS-1 on Ser(307) was elevated by the Ang II, and the elevation was suppressed by olmesartan, but not by PD123,319, in both WF and WL. These findings demonstrated that Ang II signaling contributes to cell proliferation and inhibition of the insulin signaling pathways through AT1R, but not trough AT2R, in both non-diabetic and diabetic VSMCs.
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MESH Headings
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensin II Type 2 Receptor Blockers
- Animals
- Aorta/physiopathology
- Blood Glucose/metabolism
- Cells, Cultured
- DNA Replication
- Deoxyglucose/metabolism
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/physiopathology
- Imidazoles/pharmacology
- Male
- Muscle, Smooth, Vascular/growth & development
- Muscle, Smooth, Vascular/physiopathology
- Nuclear Proteins/metabolism
- Obesity
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 1/physiology
- Receptor, Angiotensin, Type 2/drug effects
- Receptor, Angiotensin, Type 2/physiology
- Tetrazoles/pharmacology
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Affiliation(s)
- Masahiko Igarashi
- Department of Laboratory Medicine, Yamagata University School of Medicine, 2-2-2, Iida-nishi, Yamagata 990-9585, Japan.
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35
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Li T, Liu J, Zhang X, Ji G. Antidiabetic activity of lipophilic (−)-epigallocatechin-3-gallate derivative under its role of α-glucosidase inhibition. Biomed Pharmacother 2007; 61:91-6. [PMID: 17187956 DOI: 10.1016/j.biopha.2006.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
(-)-Epigallocatechin-3-gallate (EGCG), a component of catechins, has been shown to reduce blood glucose levels. In the present study, we investigated the antidiabetic activity and its mechanism of lipophilic EGCG derivative (L-EGCGd) in streptozotocin (STZ)-induced diabetic rats. L-EGCGd was chemically modified from traditional hydrophilic EGCG. After 30 days treatment, plasma levels of glucose were significantly reduced by 40.5+/-7.0% and 17.0+/-2.8% in groups administered 50 or 25 mg kg(-1)d(-1) L-EGCGd, respectively, as compared with that in the diabetic control group. Lipid metabolites, such as total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDLC) were effectively attenuated by L-EGCGd administration, but plasma HDLC levels did not change significantly. The oral glucose tolerance test (OGTT) greatly revealed the improved ability of glucose tolerance with treatment of L-EGCGd. L-EGCGd only retarded the postprandial rise in blood glucose with sucrose loading but not glucose loading. And activity of alpha-glucosidase was inhibited by 50% at the concentration of 246.6 microg ml(-1) L-EGCGd. As a result, we first demonstrated that the purified form of compound L-EGCGd possessed the hypoglycemic effect under its role of alpha-glucosidase inhibition, and therefore should be possibly accepted as an alternative oral medication protecting patients against postprandial hyperglycemic toxicity on the treatment of diabetes and its complications.
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Affiliation(s)
- Ting Li
- School of Pharmacy, East China University of Science and Technology, Mailbox 268, 130 Meilong Road, Shanghai 200237, P.R. China
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36
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Konoshita T, Wakahara S, Mizuno S, Motomura M, Aoyama C, Makino Y, Kawai Y, Kato N, Koni I, Miyamori I, Mabuchi H. Tissue gene expression of renin-angiotensin system in human type 2 diabetic nephropathy. Diabetes Care 2006; 29:848-52. [PMID: 16567826 DOI: 10.2337/diacare.29.04.06.dc05-1873] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Recent studies have proved that blockade of the renin-angiotensin system (RAS) retards the progression of diabetic nephropathy, whereas hyporeninemia is known as a typical state in diabetic subjects. The purpose of this study is to determine whether expression levels of RAS differ between nondiabetic and diabetic renal tissues with accurate quantitative method. RESEARCH DESIGN AND METHODS Subjects were 66 nondiabetic and 8 diabetic patients with biopsy-proven renal diseases. The eight diabetic subjects suffered from type 2 diabetes with overt proteinuria. Renal histology revealed typical diffuse or nodular lesions with linear IgG deposit on immunofluorescent staining and thickened basement membrane on electronic microscopy. Total RNA from a small part of the renal cortical biopsy specimens was reverse-transcribed, and the resultant cDNA was amplified for new major components of RAS (i.e., renin, renin receptor, angiotensinogen, ACE, ACE2, angiotensin II type 1 receptor, and angiotensin II type 2 receptor) and measured. RESULTS Among these components, a significant upregulation was observed in the ACE gene in diabetic renal tissue. CONCLUSIONS The results suggest that renal tissue RAS might be activated in the respect that ACE gene expression is upregulated in spite of a tendency to low renin expression in type 2 diabetic nephropathy.
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Affiliation(s)
- Tadashi Konoshita
- Third Department of Internal Medicine, Fukui University School of Medicine, Matsuoka, Fukui 910-1193, Japan.
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37
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Hakam AC, Siddiqui AH, Hussain T. Renal angiotensin II AT2 receptors promote natriuresis in streptozotocin-induced diabetic rats. Am J Physiol Renal Physiol 2005; 290:F503-8. [PMID: 16204414 DOI: 10.1152/ajprenal.00092.2005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Angiotensin II AT2 receptors have been implicated to play a role in the regulation of renal/cardiovascular functions under pathological conditions. The present study is designed to investigate the function of the AT2 receptors on renal sodium excretion and AT(2) receptor expression in the cortical membranes of streptozotocin (STZ)-induced diabetic rats. The STZ treatment led to a significant weight loss, hyperglycemia, and decrease in plasma insulin levels compared with control rats. STZ-induced diabetic rats had significantly elevated basal urine flow, urinary sodium excretion rate (U(Na)V), urinary fractional sodium excretion, and urinary cGMP compared with control rats. Infusion of PD-123319, an AT2 receptor antagonist, caused a significant decrease in U(Na)V (mumol/min) in STZ-induced diabetic rats (1 +/- 0.09 vs. 0.45 +/- 0.1) but not in control rats (0.35 +/- 0.05 vs. 0.4 +/- 0.07). The decrease in U(Na)V was associated with a significant decrease in urinary cGMP levels (pmol/min) in STZ-induced diabetic rats (21 +/- 2 vs. 10 +/- 0.8) but not in control rats (11.75 +/- 3 vs. 12.6 +/- 2). The infusion of PD-123319 did not alter glomerular filtration rate (STZ: 0.3 +/- 0.02 vs. 0.25 +/- 0.03; control: 1.4 +/- 0.05 vs. 1.5 +/- 0.09 ml/min) or mean arterial pressure (STZ: 82 +/- 3 vs. 79 +/- 3.5; control: 90 +/- 4 vs. 89 +/- 4 mmHg), suggesting a tubular effect of the drug. Western blot analysis using an AT2 receptor antibody revealed a significantly enhanced expression of the AT2 receptor protein ( approximately 45 kDa) in brush-border ( approximately 50-fold) and basolateral membranes ( approximately 80-fold) of STZ-induced diabetic compared with control rats. In conclusion, our data suggest that the tubular AT2 receptors in diabetic rats are profoundly enhanced and possibly via a cGMP pathway promote sodium excretion in this model of diabetes.
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Affiliation(s)
- Amer C Hakam
- Department of Pharmacological and Pharmaceutical Sciences, Science and Research Bldg. 2, University of Houston, 4800 Calhoun, Houston, TX 77204-5037, USA
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Giacchetti G, Sechi LA, Rilli S, Carey RM. The renin-angiotensin-aldosterone system, glucose metabolism and diabetes. Trends Endocrinol Metab 2005; 16:120-6. [PMID: 15808810 DOI: 10.1016/j.tem.2005.02.003] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In diabetes mellitus (DM), the circulating renin-angiotensin system (RAS) is suppressed, but the renal tissue RAS is activated. Hyperglycemia increases tissue angiotensin II (Ang II), which induces oxidative stress, endothelial damage and disease pathology including vasoconstriction, thrombosis, inflammation and vascular remodeling. In early DM, the type 1 Ang II (AT(1)) receptor is upregulated but the type 2 Ang II (AT(2)) receptor is downregulated. This imbalance can predispose the individual to tissue damage. Hyperglycemia also increases the production of aldosterone, which has an unknown contribution to tissue damage. The insulin resistance state is associated with upregulation of the AT(1) receptor and an increase in oxygen free radicals in endothelial tissue caused by activation of NAD(P)H oxidase. Treatment with an AT(1) receptor blocker normalizes oxidase activity and improves endothelial function. An understanding of the tissue renin-angiotensin-aldosterone system, which is a crucial factor in the progression of tissue damage in DM, is imperative for protection against tissue damage in this chronic disease.
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Affiliation(s)
- Gilberta Giacchetti
- The Division of Endocrinology, Department of Internal Medicine, Universita Politecnica della Marche, 60020 Ancona, Italy
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Singh R, Singh AK, Leehey DJ. A novel mechanism for angiotensin II formation in streptozotocin-diabetic rat glomeruli. Am J Physiol Renal Physiol 2005; 288:F1183-90. [PMID: 15701818 DOI: 10.1152/ajprenal.00159.2003] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recent evidence suggests that the intrarenal renin-angiotensin system (RAS) may play an important role in the development of glomerular changes associated with diabetic nephropathy. In this study, the glomerular RAS was examined in male Sprague-Dawley rats made diabetic with streptozotocin (STZ), and the findings compared with those obtained in control nondiabetic rats. In diabetic rat glomerular extracts, angiotensinogen and angiotensin II (ANG II) levels were increased significantly by 2.2- and 1.9-fold, respectively, compared with nondiabetic controls. No significant differences in ANG I and angiotensin-converting enzyme (ACE) levels were observed between these groups. The HPLC analysis of the glomerular extracts demonstrated that exogenous ANG I was converted into various ANG peptides including ANG II, ANG1-9, and ANG1-7. A significant increase in formation of ANG II from exogenous ANG I was observed in STZ rats compared with control rats. Preincubation of glomerular extracts with captopril resulted in a 20-30% decrease in ANG II conversion from exogenous ANG I in diabetic and control rats. The possible role of ANG1-9 in formation of ANG II was examined by HPLC. Exogenous ANG1-9 in glomerular extracts was converted into ANG II, this conversion being significantly higher in STZ rats than in control rats. These findings provide new information that ANG1-9 is produced in rat glomerular extracts, can be converted to ANG II, and that this conversion is also stimulated in diabetic rat glomeruli. Thus this study demonstrates that in diabetic rats, glomerular ANG II levels are increased due to an increase in angiotensinogen and an increase in the formation of ANG II.
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Affiliation(s)
- Rekha Singh
- Department of Medicine, Veterans Affairs Hospital, 111-L, Hines, IL 60141, USA
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Siragy HM, Carey RM. The Angiotensin Receptors: AT1 and AT2. Hypertension 2005. [DOI: 10.1016/b978-0-7216-0258-5.50101-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Schrijvers BF, De Vriese AS, Flyvbjerg A. From hyperglycemia to diabetic kidney disease: the role of metabolic, hemodynamic, intracellular factors and growth factors/cytokines. Endocr Rev 2004; 25:971-1010. [PMID: 15583025 DOI: 10.1210/er.2003-0018] [Citation(s) in RCA: 242] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
At present, diabetic kidney disease affects about 15-25% of type 1 and 30-40% of type 2 diabetic patients. Several decades of extensive research has elucidated various pathways to be implicated in the development of diabetic kidney disease. This review focuses on the metabolic factors beyond blood glucose that are involved in the pathogenesis of diabetic kidney disease, i.e., advanced glycation end-products and the aldose reductase system. Furthermore, the contribution of hemodynamic factors, the renin-angiotensin system, the endothelin system, and the nitric oxide system, as well as the prominent role of the intracellular signaling molecule protein kinase C are discussed. Finally, the respective roles of TGF-beta, GH and IGFs, vascular endothelial growth factor, and platelet-derived growth factor are covered. The complex interplay between these different pathways will be highlighted. A brief introduction to each system and description of its expression in the normal kidney is followed by in vitro, experimental, and clinical evidence addressing the role of the system in diabetic kidney disease. Finally, well-known and potential therapeutic strategies targeting each system are discussed, ending with an overall conclusion.
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Affiliation(s)
- Bieke F Schrijvers
- Medical Department M/Medical Research Laboratories, Clinical Institute, Aarhus University Hospital, Nørrebrogade 44, DK-8000 Aarhus C, Denmark
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Li N, Zimpelmann J, Cheng K, Wilkins JA, Burns KD. The role of angiotensin converting enzyme 2 in the generation of angiotensin 1-7 by rat proximal tubules. Am J Physiol Renal Physiol 2004; 288:F353-62. [PMID: 15467007 DOI: 10.1152/ajprenal.00144.2004] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ANG converting enzyme (ACE) 2 (ACE2) is a homologue of ACE, which is not blocked by conventional ACE inhibitors. ACE2 converts ANG 1-10 (ANG I) to ANG 1-9, which can be hydrolyzed by ACE to form the biologically active peptide ANG 1-7. ACE2 is expressed in the kidney, but its precise intrarenal localization is unclear, and the role of intrarenal ACE2 in the production of ANG 1-7 is unknown. The present studies determined the relative distribution of ACE2 in the rat kidney and defined its role in the generation of ANG 1-7 in proximal tubule. In microdissected rat nephron segments, semiquantitative RT-PCR revealed that ACE2 mRNA was widely expressed, with relatively high levels in proximal straight tubule (PST). Immunohistochemistry demonstrated ACE2 protein in tubular segments, glomeruli, and endothelial cells. Utilizing mass spectrometry, incubation of isolated PSTs with ANG I (10(-6) M) led to generation of ANG 1-7 (sensitivity of detection > 1 x 10(-9) M), accompanied by the formation of ANG 1-8 (ANG II) and ANG 1-9. The ACE2 inhibitor DX600 completely blocked ANG I-mediated generation of ANG 1-7. Incubation of PSTs with ANG 1-9 also led to generation of ANG 1-7, an effect blocked by the ACE inhibitor captopril or enalaprilat, but not by DX600. Incubation of PSTs with ANG II or luminal perfusion of ANG II did not result in detection of ANG 1-7. The results indicate that ACE2 is widely expressed in rat nephron segments and contributes to the production of ANG 1-7 from ANG I in PST. ANG II may not be a major substrate for ACE2 in isolated PST. The data suggest that ACE2-mediated production of ANG 1-7 represents an important component of the proximal tubular renin-ANG system.
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Affiliation(s)
- Ningjun Li
- Department of Medicine, Ottawa Hospital, and the Kidney Research Centre, Ottawa Health Research Institute, University of Ottawa, Ontario, Canada
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Awad AS, Webb RL, Carey RM, Siragy HM. Renal nitric oxide production is decreased in diabetic rats and improved by AT1 receptor blockade. J Hypertens 2004; 22:1571-7. [PMID: 15257181 DOI: 10.1097/01.hjh.0000133718.86451.6a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Diabetes mellitus is associated with increased incidence of cardiovascular complications. Lack of nitric oxide production may exacerbate these complications. We hypothesized that diabetes decreases renal nitric oxide (NO) production, an effect that is reversed via inhibition of angiotensin subtype-1 receptor. METHODS We monitored changes in renal interstitial fluid nitric oxide by a microdialysis technique in the renal cortex of conscious Sprague-Dawley rats. Rats (n = 8 each group) were given streptozotocin 30 mg/kg intravenously to induce diabetes. Changes in renal interstitial fluid angiotensin II and NO were evaluated at baseline before and over 12 weeks during the development of diabetes and at 4 and 8 h after oral administration of the angiotensin subtype-1 (AT1) receptor blockers, losartan (30 mg/kg) or valsartan (10 mg/kg). RESULTS Renal interstitial fluid angiotensin II significantly increased after development of diabetes. In contrast, basal renal interstitial fluid nitric oxide decreased significantly over 12 weeks after development of diabetes. Both losartan and valsartan caused a further increase in renal angiotensin II levels. Some 4 h after administration, there was significantly greater increase in renal nitric oxide after administration of valsartan than of losartan. At 8 h post- treatment, only valsartan caused a significant increase in renal nitric oxide levels. CONCLUSION These results demonstrate that diabetes mellitus is associated with an increase in renal production of angiotensin II, while renal production of nitric oxide is reduced. The decrease in renal NO is reversed by AT1 receptor blockade.
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Affiliation(s)
- Alaa S Awad
- Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
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Tejera N, Gómez-Garre D, Lázaro A, Gallego-Delgado J, Alonso C, Blanco J, Ortiz A, Egido J. Persistent proteinuria up-regulates angiotensin II type 2 receptor and induces apoptosis in proximal tubular cells. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:1817-26. [PMID: 15111328 PMCID: PMC1615640 DOI: 10.1016/s0002-9440(10)63740-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/09/2004] [Indexed: 11/22/2022]
Abstract
Apoptosis is implicated in the progressive cell loss and fibrosis both at glomerular and tubulointerstitial level. In this study, we examined the potential mechanisms by which persistent proteinuria (protein-overload model) could induce apoptosis. After uninephrectomy (UNX), Wistar rats received daily injections of 0.5 g of bovine serum albumin (BSA)/100 g body weight or saline. Both at day 8 and day 28, rats receiving BSA had proteinuria and renal lesions characterized by tubular atrophy and/or dilation and mononuclear cell infiltration. In relation to control-UNX rats, renal cortex of nephritic rats showed an increment in AT2 mRNA (reverse transcriptase-polymerase chain reaction) and protein (Western blot) expression. In both groups, AT2 receptor immunostaining was mainly localized in proximal tubular cells. Rats with persistent proteinuria showed a significantly increased number of terminal dUTP nick-end labeling positive apoptotic cells compared with UNX-controls, both in glomeruli and tubulointerstitium. Double staining for apoptosis and AT2 receptor showed that most terminal dUTP nick-end labeling positive cells were found in tubules expressing AT2 receptor. Using an antibody that recognizes the active form caspase-3, we observed an increment in caspase-3 activation in rats receiving BSA with respect to those receiving saline. Rats with persistent proteinuria showed a diminution in the phosphorylation of Bcl-2 with respect to UNX-controls both at day 8 and day 28. By contrast, no changes were observed either in the Bax or in the Bcl-2 protein levels. The administration of BSA to UNX rats induced a diminution in the phosphorylation of ERK with respect to UNX-control at all times studied. The changes observed in ERK activities took place without alterations of ERK1/2 protein levels. In summary, our data suggest that persistent proteinuria causes apoptosis in tubular cells through the activation of AT2 receptor, which can, in turn, inhibit MAP kinase (ERK1/2) activation and Bcl-2 phosphorylation.
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Affiliation(s)
- Nuria Tejera
- Renal and Vascular Laboratory, Fundación Jiménez Díaz-Universidad Autónoma, Madrid, Spain
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Abstract
Angiotensin II, via activation of AT1 receptors in the kidney regulates sodium/fluid homeostasis and blood pressure. An exaggerated action of angiotensin II mediated via activation of AT1 receptors has been implicated in the increased renal sodium retention and the resetting of the pressure natriuresis in obesity related hypertension. Treatment of obese Zucker rats with AT1 receptor blockers reduces blood pressure to a greater extent and produces greater natriuresis. Also, there is an increased membranal AT1 receptor numbers and angiotensin II produces greater activation of sodium transporters in the isolated tubules from obese Zucker rats. Interestingly, AT2 receptors, which are believed to be beneficial to the renal and cardiovascular function in terms of their action on kidney and blood vessels, are greatly increased in proximal tubular membranes of obese Zucker rats. Whole animal and in vitro studies indicate that higher plasma insulin level, generally associated with obesity, is responsible for the up-regulation of both AT1 and AT2 receptors in the kidney. Determining the consequence of selective blocking of AT1 receptors and/or activation of the AT2 receptors on renal and cardiovascular function, and the effect of lowering insulin on these receptors present an important area of further investigation in obesity.
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Affiliation(s)
- Tahir Hussain
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas 77204, USA.
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Mezzano S, Droguett A, Burgos ME, Ardiles LG, Flores CA, Aros CA, Caorsi I, Vío CP, Ruiz-Ortega M, Egido J. Renin-angiotensin system activation and interstitial inflammation in human diabetic nephropathy. KIDNEY INTERNATIONAL. SUPPLEMENT 2003:S64-70. [PMID: 12969130 DOI: 10.1046/j.1523-1755.64.s86.12.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The molecular mechanisms of renal injury in diabetic nephropathy (DN) are not completely understood, although inflammatory cells play a key role. The renin-angiotensin system (RAS) is involved in kidney damage; however, few studies have examined the localization of RAS components in human DN. Our aim was to investigate in renal biopsies the expression of RAS and their correlation with proinflammatory parameters and renal injury. METHODS The biopsies from 10 patients with type 2 diabetes mellitus and overt nephropathy were studied for the expression of RAS components by immunohistochemistry (IH). In addition, by Southwestern histochemistry we studied the in situ detection of the activated nuclear factor kappa B (NFkappaB), and by IH and/or in situ hybridization (ISH), the expression of monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T cell expressed and secreted (RANTES), whose genes are regulated by NFkappaB. RESULTS Angiotensin-converting enzyme (ACE) immunostaining was elevated in tubular cells and appeared in interstitial cells. Elevated levels of angiotensin II (Ang II) immunostaining were observed in tubular and infiltrating interstitial cells. There was also a down-regulation of AT1 and up-regulation of AT2 receptors. An activation of NFkappaB and a marked up-regulation of NFkappaB-dependent chemokines mainly in tubular cells was observed. Elevated levels of NFkappaB, chemokines, and Ang II in tubules were correlated with proteinuria and interstitial cell infiltration. CONCLUSIONS Our results show that in human DN, RAS components are modified in renal compartments, showing elevated local Ang II production, activation of tubular cells, and induction of proinflammatory parameters. These data suggest that Ang II contributes to the renal inflammatory process, and may explain the molecular mechanisms of the beneficial effect of RAS blockade.
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Affiliation(s)
- Sergio Mezzano
- Division of Nephrology, School of Medicine, Universidad Austral, Valdivia, Chile.
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Abstract
The renin-angiotensin system (RAS) is a coordinated cascade of proteins and peptide hormones, the principal effector of which is angiotensin II (ANG II). Evidence now indicates that the kidney regulates its function via a self-contained RAS in a paracrine fashion. In diabetic nephropathy, the intrarenal generation of ANG II is increased, in spite of suppression of the systemic RAS. This increase can contribute to the progression of diabetic nephropathy via several hemodynamic, tubular and growth-promoting actions. ANG II induces insulin resistance. ANG II type-1 (AT(1)) and type-2 (AT(2)) receptors are downregulated in chronic diabetes, but decreased AT(2) receptor expression might contribute to early diabetic nephropathy by reducing AT(2) receptor-mediated beneficial actions that are counter-regulatory to those of the AT(1) receptor. AT(2) receptor stimulation might account for part of the renal protection seen with AT(1) receptor blockade. A rat model of accelerated diabetic nephropathy is the (mREN-2) 27 renin transgenic rat treated with streptozotocin in which both the intrarenal and extrarenal RAS is activated.
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Affiliation(s)
- Robert M Carey
- Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Box 801414, University of Virginia Health System, Charlottesville, VA 22908-1414, USA.
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Burns KD, Li N. The role of angiotensin II-stimulated renal tubular transport in hypertension. Curr Hypertens Rep 2003; 5:165-71. [PMID: 12642017 DOI: 10.1007/s11906-003-0074-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The kidney contains a renin-angiotensin system that appears to regulate systemic blood pressure. Angiotensin II (Ang II) has stimulatory effects on sodium transport in multiple nephron segments via binding to plasma membrane AT(1) receptors. In the proximal tubule, Ang II production is substantial. The stimulatory effect of Ang II on proximal sodium transport is enhanced by renal nerves, and is associated with internalization of apical and basolateral receptors. In the cortical collecting duct, AT(1) receptors stimulate transport through apical sodium channels, and in the inner medulla, urea transport is enhanced by Ang II, contributing to increased sodium and water reabsorption. AT(1) receptors may also be linked to increased expression of certain tubular sodium transporters. In contrast to the stimulatory effects of AT(1) receptors on sodium transport, AT(2) receptors expressed in the adult kidney are linked to increased urinary sodium excretion and decreased blood pressure. This suggests that renal tubular AT(1) receptor activation serves as a protective mechanism to increase sodium reabsorption and blood pressure when extracellular fluid volume is threatened, whereas AT(2) receptors dampen this response. The interplay between these two receptor pathways in the kidney could have significant effects on long-term blood pressure control.
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Affiliation(s)
- Kevin D Burns
- Division of Nephrology, The Ottawa Hospital and University of Ottawa, 1967 Riverside Drive, Room 535A, Ontario K1H 7W9, Canada.
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Tikellis C, Johnston CI, Forbes JM, Burns WC, Burrell LM, Risvanis J, Cooper ME. Characterization of renal angiotensin-converting enzyme 2 in diabetic nephropathy. Hypertension 2003; 41:392-7. [PMID: 12623933 DOI: 10.1161/01.hyp.0000060689.38912.cb] [Citation(s) in RCA: 269] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
ACE2, initially cloned from a human heart, is a recently described homologue of angiotensin-converting enzyme (ACE) but contains only a single enzymatic site that catalyzes the cleavage of angiotensin I to angiotensin 1-9 [Ang(1-9)] and is not inhibited by classic ACE inhibitors. It also converts angiotensin II to Ang(1-7). Although the role of ACE2 in the regulation of the renin-angiotensin system is not known, the renin-angiotensin system has been implicated in the pathogenesis of diabetic complications and in particular in diabetic nephropathy. Therefore, the aim of this study was to assess the possible involvement of this new enzyme in the kidney from diabetic Sprague-Dawley rats to compare and contrast it to ACE. ACE2 and ACE gene and protein expression were measured in the kidney after 24 weeks of streptozocin diabetes. ACE2 and ACE mRNA levels were decreased in diabetic renal tubules by approximately 50% and were not influenced by ACE inhibitor treatment with ramipril. By immunostaining, both ACE2 and ACE protein were localized predominantly to renal tubules. In the diabetic kidney, there was reduced ACE2 protein expression that was prevented by ACE inhibitor therapy. The identification of ACE2 in the kidney, its modulation in diabetes, and the recent description that this enzyme plays a biological role in the generation and degradation of various angiotensin peptides provides a rationale to further explore the role of this enzyme in various pathophysiological states including diabetic complications.
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Affiliation(s)
- Christos Tikellis
- Department of Medicine, University of Melbourne, Austin and Repatriation Medical Centre, Melbourne, Australia
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50
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Wei Y, Wang W. Angiotensin II stimulates basolateral K channels in rat cortical collecting ducts. Am J Physiol Renal Physiol 2003; 284:F175-81. [PMID: 12388389 DOI: 10.1152/ajprenal.00211.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We used the patch-clamp technique to study the effects of angiotensin II (ANG II) on basolateral K channels in cortical collecting ducts (CCDs). Application of ANG II (100 pM-100 nM) increased the activity of basolateral 18-pS K channels. This effect of ANG II was completely abolished by losartan, which is an antagonist of type 1 angiotensin (AT(1)) receptors. In contrast, inhibition of type 2 angiotensin (AT(2)) receptors did not block the stimulatory effect of ANG II. Also, application of ANG II significantly increased intracellular Ca(2+) concentrations, which were measured with fura 2 dye. To explore the role of Ca(2+)-dependent pathways in the regulation of basolateral K channels, the effects of ANG II on channel activity were examined in the presence of arachidonyltrifluoromethyl ketone to inhibit phospholipase A(2) (PLA(2)), GF-109203X [a protein kinase C (PKC) inhibitor], and N(G)-nitro-l-arginine methyl ester (l-NAME) to inhibit nitric oxide synthase. Inhibition of either PLA(2) or PKC did not block the effect of ANG II on basolateral K-channel activity. However, the stimulatory effect of ANG II was absent in the CCDs treated with l-NAME. Moreover, addition of the membrane-permeant 8-bromo-guanosine 3',5'-cyclic monophosphate (8-bromo-cGMP) not only increased channel activity but also abolished the stimulatory effect of ANG II on channel activity. We conclude that ANG II increases basolateral K-channel activity via the stimulation of AT(1) receptors, and the stimulatory effect of ANG II is mediated by a nitric oxide-dependent cGMP pathway.
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Affiliation(s)
- Yuan Wei
- Department of Pharmacology, New York Medical College, Valhalla 10595, USA
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