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Mraheil MA, Toque HA, La Pietra L, Hamacher J, Phanthok T, Verin A, Gonzales J, Su Y, Fulton D, Eaton DC, Chakraborty T, Lucas R. Dual Role of Hydrogen Peroxide as an Oxidant in Pneumococcal Pneumonia. Antioxid Redox Signal 2021; 34:962-978. [PMID: 32283950 PMCID: PMC8035917 DOI: 10.1089/ars.2019.7964] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Significance:Streptococcus pneumoniae (Spn), a facultative anaerobic Gram-positive human pathogen with increasing rates of penicillin and macrolide resistance, is a major cause of lower respiratory tract infections worldwide. Pneumococci are a primary agent of severe pneumonia in children younger than 5 years and of community-acquired pneumonia in adults. A major defense mechanism toward Spn is the generation of reactive oxygen species, including hydrogen peroxide (H2O2), during the oxidative burst of neutrophils and macrophages. Paradoxically, Spn produces high endogenous levels of H2O2 as a strategy to promote colonization. Recent Advances: Pneumococci, which express neither catalase nor common regulators of peroxide stress resistance, have developed unique mechanisms to protect themselves from H2O2. Spn generates high levels of H2O2 as a strategy to promote colonization. Production of H2O2 moreover constitutes an important virulence phenotype and its cellular activities overlap and complement those of other virulence factors, such as pneumolysin, in modulating host immune responses and promoting organ injury. Critical Issues: This review examines the dual role of H2O2 in pneumococcal pneumonia, from the viewpoint of both the pathogen (defense mechanisms, lytic activity toward competing pathogens, and virulence) and the resulting host-response (inflammasome activation, endoplasmic reticulum stress, and damage to the alveolar-capillary barrier in the lungs). Future Directions: An understanding of the complexity of H2O2-mediated host-pathogen interactions is necessary to develop novel strategies that target these processes to enhance lung function during severe pneumonia.
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Affiliation(s)
- Mobarak Abu Mraheil
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Haroldo A Toque
- Vascular Biology Center and Medical College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Luigi La Pietra
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Juerg Hamacher
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland.,Internal Medicine V-Pneumology, Allergology, Respiratory and Environmental Medicine, Faculty of Medicine, Saarland University, Saarbrücken, Germany
| | - Tenzing Phanthok
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Alexander Verin
- Vascular Biology Center and Medical College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Joyce Gonzales
- Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Yunchao Su
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - David Fulton
- Vascular Biology Center and Medical College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
| | - Douglas C Eaton
- Department of Medicine, Emory School of Medicine, Atlanta, Georgia, USA
| | - Trinad Chakraborty
- Institute for Medical Microbiology, Justus-Liebig University, Giessen, Germany
| | - Rudolf Lucas
- Vascular Biology Center and Medical College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, USA.,Department of Medicine, Medical College of Georgia at Augusta University, Augusta, Georgia, USA
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2
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Atawia RT, Toque HA, Chen J, Meghil MM, Benson TW, Yiew NKH, Bunch KL, Cutler CW, Weintraub NL, Caldwell RB, Caldwell RW. Obesity‐induced metabolic and vascular dysregulation: Implication of arginase. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.514.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Reem T. Atawia
- Department of Pharmacology and ToxicologyAugusta UniversityAugustaGA
| | - Haroldo A. Toque
- Department of Pharmacology and ToxicologyAugusta UniversityAugustaGA
- Vascular Biology Center, Medical College of Georgia, Augusta UniversityAugustaGA
| | - Jijun Chen
- Department of Pharmacology and ToxicologyAugusta UniversityAugustaGA
| | - Mohamed M. Meghil
- Departments of Oral Biology and PeriodonticsDental College of Georgia, Augusta UniversityAugustaGA
| | - Tyler W. Benson
- Vascular Biology Center, Medical College of Georgia, Augusta UniversityAugustaGA
| | - Nicole K. H. Yiew
- Department of Pharmacology and ToxicologyAugusta UniversityAugustaGA
| | | | - Christopher W. Cutler
- Departments of Oral Biology and PeriodonticsDental College of Georgia, Augusta UniversityAugustaGA
| | - Neal L. Weintraub
- Vascular Biology Center, Medical College of Georgia, Augusta UniversityAugustaGA
| | - Ruth B. Caldwell
- Vascular Biology Center, Medical College of Georgia, VA Medical CenterAugustaGA
- VA Medical CenterAugustaGA
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Madaio MP, Czikora I, Kvirkvelia N, McMenamin M, Yue Q, Liu T, Toque HA, Sridhar S, Covington K, Alaisami R, O'Connor PM, Caldwell RW, Chen JK, Clauss M, Brands MW, Eaton DC, Romero MJ, Lucas R. The TNF-derived TIP peptide activates the epithelial sodium channel and ameliorates experimental nephrotoxic serum nephritis. Kidney Int 2019; 95:1359-1372. [PMID: 30905471 DOI: 10.1016/j.kint.2018.12.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023]
Abstract
In mice, the initial stage of nephrotoxic serum-induced nephritis (NTN) mimics antibody-mediated human glomerulonephritis. Local immune deposits generate tumor necrosis factor (TNF), which activates pro-inflammatory pathways in glomerular endothelial cells (GECs) and podocytes. Because TNF receptors mediate antibacterial defense, existing anti-TNF therapies can promote infection; however, we have previously demonstrated that different functional domains of TNF may have opposing effects. The TIP peptide mimics the lectin-like domain of TNF, and has been shown to blunt inflammation in acute lung injury without impairing TNF receptor-mediated antibacterial activity. We evaluated the impact of TIP peptide in NTN. Intraperitoneal administration of TIP peptide reduced inflammation, proteinuria, and blood urea nitrogen. The protective effect was blocked by the cyclooxygenase inhibitor indomethacin, indicating involvement of prostaglandins. Targeted glomerular delivery of TIP peptide improved pathology in moderate NTN and reduced mortality in severe NTN, indicating a local protective effect. We show that TIP peptide activates the epithelial sodium channel(ENaC), which is expressed by GEC, upon binding to the channel's α subunit. In vitro, TNF treatment of GEC activated pro-inflammatory pathways and decreased the generation of prostaglandin E2 and nitric oxide, which promote recovery from NTN. TIP peptide counteracted these effects. Despite the capacity of TIP peptide to activate ENaC, it did not increase mean arterial blood pressure in mice. In the later autologous phase of NTN, TIP peptide blunted the infiltration of Th17 cells. By countering the deleterious effects of TNF through direct actions in GEC, TIP peptide could provide a novel strategy to treat glomerular inflammation.
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Affiliation(s)
- Michael P Madaio
- Department of Medicine, Augusta University, Augusta, Georgia, USA.
| | - Istvan Czikora
- Vascular Biology Center, Augusta University, Augusta, Georgia, USA; Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Nino Kvirkvelia
- Department of Medicine, Augusta University, Augusta, Georgia, USA
| | | | - Qiang Yue
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ting Liu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Haroldo A Toque
- Vascular Biology Center, Augusta University, Augusta, Georgia, USA
| | - Supriya Sridhar
- Vascular Biology Center, Augusta University, Augusta, Georgia, USA
| | | | - Rabei Alaisami
- Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Paul M O'Connor
- Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Robert W Caldwell
- Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA
| | - Jian-Kang Chen
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Matthias Clauss
- Indiana Center for Vascular Biology and Medicine, RLR-VA Medical Center, Indianapolis, Indiana, USA
| | - Michael W Brands
- Department of Physiology, Augusta University, Augusta, Georgia, USA
| | - Douglas C Eaton
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Maritza J Romero
- Vascular Biology Center, Augusta University, Augusta, Georgia, USA; Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA; Department of Anesthesiology and Perioperative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Rudolf Lucas
- Department of Medicine, Augusta University, Augusta, Georgia, USA; Vascular Biology Center, Augusta University, Augusta, Georgia, USA; Department of Pharmacology and Toxicology, Augusta University, Augusta, Georgia, USA.
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Abstract
Obesity has reached epidemic proportions and its prevalence is climbing. Obesity is characterized by hypertrophied adipocytes with a dysregulated adipokine secretion profile, increased recruitment of inflammatory cells, and impaired metabolic homeostasis that eventually results in the development of systemic insulin resistance, a phenotype of type 2 diabetes. Nitric oxide synthase (NOS) is an enzyme that converts L-arginine to nitric oxide (NO), which functions to maintain vascular and adipocyte homeostasis. Arginase is a ureohydrolase enzyme that competes with NOS for L-arginine. Arginase activity/expression is upregulated in obesity, which results in diminished bioavailability of NO, impairing both adipocyte and vascular endothelial cell function. Given the emerging role of NO in the regulation of adipocyte physiology and metabolic capacity, this review explores the interplay between arginase and NO, and their effect on the development of metabolic disorders, cardiovascular diseases, and mitochondrial dysfunction in obesity. A comprehensive understanding of the mechanisms involved in the development of obesity-induced metabolic and vascular dysfunction is necessary for the identification of more effective and tailored therapeutic avenues for their prevention and treatment.
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Affiliation(s)
- Reem T Atawia
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University. Augusta, GA 30904, USA
| | - Katharine L Bunch
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University. Augusta, GA 30904, USA
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology,and Vascular Biology Center, Medical College of Georgia, Augusta University. Augusta, GA 30904, USA
| | - Ruth B Caldwell
- Vascular Biology Center, Medical College of Georgia, Augusta University. Augusta, GA 30904, USA
| | - Robert W Caldwell
- Vascular Biology Center, Medical College of Georgia, Augusta University. Augusta, GA 30904,USA,
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5
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Chandra S, Fulton DJR, Caldwell RB, Caldwell RW, Toque HA. Hyperglycemia-impaired aortic vasorelaxation mediated through arginase elevation: Role of stress kinase pathways. Eur J Pharmacol 2018; 844:26-37. [PMID: 30502342 DOI: 10.1016/j.ejphar.2018.11.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/15/2018] [Accepted: 11/20/2018] [Indexed: 11/15/2022]
Abstract
Diabetes-induced vascular endothelial dysfunction has been reported to involve hyperglycemia-induced increases in arginase activity. However, upstream mediators of this effect are not clear. Here, we have tested involvement of Rho kinase, ERK1/2 and p38 MAPK pathways in this process. Studies were performed with aortas isolated from wild type or hemizygous arginase 1 knockout (Arg1+/-) mice and bovine aortic endothelial cells exposed to high glucose (HG, 25 mmol/l) or normal glucose (NG, 5.5 mmol/l) conditions for different times. Effects of inhibitors of arginase, p38 MAPK, ERK1/2 or ROCK and ex vivo adenoviral delivery of active Arg1 and inactive (D128-Arg1) cDNA were also determined. Exposure in wild type aorta or endothelial cells to HG significantly increased arginase activity and Arg1 expression and impaired aortic relaxation. Transduction of wild type aorta with active Arg1 cDNA impaired vascular relaxation, whereas inactive Arg1 had no effect. The HG-induced vascular endothelial dysfunction was associated with increased phosphorylation (activation) of ERK1/2 and p38 MAPK. Pretreatment with inhibitors of ERK1/2, p38 MAPK, ROCK or arginase blocked HG-induced elevation of arginase activity and Arg1 expression and prevented the vascular dysfunction. Inhibition of ROCK blunted the HG-induced activation of ERK1/2 and p38 MAPK. In summary, activated ROCK and subsequent activation of ERK1/2 or p38 MAPK elevates arginase activity and Arg1 expression in hyperglycemic states. Targeting this pathway may provide an effective means for preventing diabetes/hyperglycemia-induced vascular endothelial dysfunction.
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Affiliation(s)
- Surabhi Chandra
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA; Department of Biology, University of Nebraska-Kearney, Kearney, NE, USA.
| | - David J R Fulton
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA; Vascular Biology Center, Augusta University, Augusta, GA, USA
| | - Ruth B Caldwell
- Vascular Biology Center, Augusta University, Augusta, GA, USA; Cell Biology and Anatomy, Augusta University, Augusta, GA, USA; Veterans Administration Medical Center, Augusta, GA, USA
| | - R William Caldwell
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA; Vascular Biology Center, Augusta University, Augusta, GA, USA
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA; Vascular Biology Center, Augusta University, Augusta, GA, USA
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6
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Fouda AY, Xu Z, Shosha E, Lemtalsi T, Chen J, Toque HA, Tritz R, Cui X, Stansfield BK, Huo Y, Rodriguez PC, Smith SB, Caldwell RW, Narayanan SP, Caldwell RB. Arginase 1 promotes retinal neurovascular protection from ischemia through suppression of macrophage inflammatory responses. Cell Death Dis 2018; 9:1001. [PMID: 30254218 PMCID: PMC6156564 DOI: 10.1038/s41419-018-1051-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/24/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022]
Abstract
The lack of effective therapies to limit neurovascular injury in ischemic retinopathy is a major clinical problem. This study aimed to examine the role of ureohydrolase enzyme, arginase 1 (A1), in retinal ischemia-reperfusion (IR) injury. A1 competes with nitric oxide synthase (NOS) for their common substrate l-arginine. A1-mediated l-arginine depletion reduces nitric oxide (NO) formation by NOS leading to vascular dysfunction when endothelial NOS is involved but prevents inflammatory injury when inducible NOS is involved. Studies were performed using wild-type (WT) mice, global A1+/− knockout (KO), endothelial-specific A1 KO, and myeloid-specific A1 KO mice subjected to retinal IR injury. Global as well as myeloid-specific A1 KO mice showed worsened IR-induced neuronal loss and retinal thinning. Deletion of A1 in endothelial cells had no effect, while treatment with PEGylated (PEG) A1 improved neuronal survival in WT mice. In addition, A1+/− KO mice showed worsened vascular injury manifested by increased acellular capillaries. Western blotting analysis of retinal tissue showed increased inflammatory and necroptotic markers with A1 deletion. In vitro experiments showed that macrophages lacking A1 exhibit increased inflammatory response upon LPS stimulation. PEG-A1 treatment dampened this inflammatory response and decreased the LPS-induced metabolic reprogramming. Moreover, intravitreal injection of A1 KO macrophages or systemic macrophage depletion with clodronate liposomes increased neuronal loss after IR injury. These results demonstrate that A1 reduces IR injury-induced retinal neurovascular degeneration via dampening macrophage inflammatory responses. Increasing A1 offers a novel strategy for limiting neurovascular injury and promoting macrophage-mediated repair.
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Affiliation(s)
- Abdelrahman Y Fouda
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Vascular Biology Center, Augusta University, Augusta, GA, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Zhimin Xu
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Vascular Biology Center, Augusta University, Augusta, GA, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Esraa Shosha
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Vascular Biology Center, Augusta University, Augusta, GA, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Tahira Lemtalsi
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Vascular Biology Center, Augusta University, Augusta, GA, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Jijun Chen
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA
| | - Haroldo A Toque
- Vascular Biology Center, Augusta University, Augusta, GA, USA.,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA
| | - Rebekah Tritz
- Vascular Biology Center, Augusta University, Augusta, GA, USA
| | - Xuezhi Cui
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.,Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Brian K Stansfield
- Vascular Biology Center, Augusta University, Augusta, GA, USA.,Department of Pediatrics, Augusta University, Augusta, GA, USA
| | - Yuqing Huo
- Vascular Biology Center, Augusta University, Augusta, GA, USA.,Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA
| | | | - Sylvia B Smith
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.,Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA.,Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - R William Caldwell
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.,Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA
| | - S Priya Narayanan
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Vascular Biology Center, Augusta University, Augusta, GA, USA.,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA.,Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA
| | - Ruth B Caldwell
- Charlie Norwood VA Medical Center, Augusta, GA, USA. .,Vascular Biology Center, Augusta University, Augusta, GA, USA. .,James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA. .,Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, USA. .,Department of Ophthalmology, Augusta University, Augusta, GA, USA.
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7
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Caldwell RW, Rodriguez PC, Toque HA, Narayanan SP, Caldwell RB. Arginase: A Multifaceted Enzyme Important in Health and Disease. Physiol Rev 2018; 98:641-665. [PMID: 29412048 PMCID: PMC5966718 DOI: 10.1152/physrev.00037.2016] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 12/15/2022] Open
Abstract
The arginase enzyme developed in early life forms and was maintained during evolution. As the last step in the urea cycle, arginase cleaves l-arginine to form urea and l-ornithine. The urea cycle provides protection against excess ammonia, while l-ornithine is needed for cell proliferation, collagen formation, and other physiological functions. In mammals, increases in arginase activity have been linked to dysfunction and pathologies of the cardiovascular system, kidney, and central nervous system and also to dysfunction of the immune system and cancer. Two important aspects of the excessive activity of arginase may be involved in diseases. First, overly active arginase can reduce the supply of l-arginine needed for the production of nitric oxide (NO) by NO synthase. Second, too much l-ornithine can lead to structural problems in the vasculature, neuronal toxicity, and abnormal growth of tumor cells. Seminal studies have demonstrated that increased formation of reactive oxygen species and key inflammatory mediators promote this pathological elevation of arginase activity. Here, we review the involvement of arginase in diseases affecting the cardiovascular, renal, and central nervous system and cancer and discuss the value of therapies targeting the elevated activity of arginase.
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Affiliation(s)
- R William Caldwell
- Department of Pharmacology & Toxicology, Vision Discovery Institute, Department of Medicine-Hematology and Oncology, Department of Occupational Therapy, School of Allied Health Sciences, and Vascular Biology Center, Medical College of Georgia, Augusta University , Augusta, Georgia ; and VA Medical Center, Augusta, Georgia
| | - Paulo C Rodriguez
- Department of Pharmacology & Toxicology, Vision Discovery Institute, Department of Medicine-Hematology and Oncology, Department of Occupational Therapy, School of Allied Health Sciences, and Vascular Biology Center, Medical College of Georgia, Augusta University , Augusta, Georgia ; and VA Medical Center, Augusta, Georgia
| | - Haroldo A Toque
- Department of Pharmacology & Toxicology, Vision Discovery Institute, Department of Medicine-Hematology and Oncology, Department of Occupational Therapy, School of Allied Health Sciences, and Vascular Biology Center, Medical College of Georgia, Augusta University , Augusta, Georgia ; and VA Medical Center, Augusta, Georgia
| | - S Priya Narayanan
- Department of Pharmacology & Toxicology, Vision Discovery Institute, Department of Medicine-Hematology and Oncology, Department of Occupational Therapy, School of Allied Health Sciences, and Vascular Biology Center, Medical College of Georgia, Augusta University , Augusta, Georgia ; and VA Medical Center, Augusta, Georgia
| | - Ruth B Caldwell
- Department of Pharmacology & Toxicology, Vision Discovery Institute, Department of Medicine-Hematology and Oncology, Department of Occupational Therapy, School of Allied Health Sciences, and Vascular Biology Center, Medical College of Georgia, Augusta University , Augusta, Georgia ; and VA Medical Center, Augusta, Georgia
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8
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Nunes KP, Bomfim GF, Toque HA, Szasz T, Clinton Webb R. Toll-like receptor 4 (TLR4) impairs nitric oxide contributing to Angiotensin II-induced cavernosal dysfunction. Life Sci 2017; 191:219-226. [DOI: 10.1016/j.lfs.2017.10.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/10/2017] [Accepted: 10/10/2017] [Indexed: 10/18/2022]
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Bhatta A, Yao L, Xu Z, Toque HA, Chen J, Atawia RT, Fouda AY, Bagi Z, Lucas R, Caldwell RB, Caldwell RW. Obesity-induced vascular dysfunction and arterial stiffening requires endothelial cell arginase 1. Cardiovasc Res 2017; 113:1664-1676. [PMID: 29048462 PMCID: PMC6410953 DOI: 10.1093/cvr/cvx164] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 03/16/2017] [Accepted: 08/09/2017] [Indexed: 02/04/2023] Open
Abstract
AIMS Elevation of arginase activity has been linked to vascular dysfunction in diabetes and hypertension by a mechanism involving decreased nitric oxide (NO) bioavailability due to L-arginine depletion. Excessive arginase activity also can drive L-arginine metabolism towards the production of ornithine, polyamines, and proline, promoting proliferation of vascular smooth muscle cells and collagen formation, leading to perivascular fibrosis. We hypothesized that there is a specific involvement of arginase 1 expression within the vascular endothelial cells in this pathology. METHODS AND RESULTS To test this proposition, we used models of type 2 diabetes and metabolic syndrome. Studies were performed using wild type (WT), endothelial-specific arginase 1 knockout (EC-A1-/-) and littermate controls(A1con) mice fed high fat-high sucrose (HFHS) or normal diet (ND) for 6 months and isolated vessels exposed to palmitate-high glucose (PA/HG) media. Some WT mice or isolated vessels were treated with an arginase inhibitor, ABH [2-(S)-amino-6-boronohexanoic acid. In WT mice, the HFHS diet promoted increases in body weight, fasting blood glucose, and post-prandial insulin levels along with arterial stiffening and fibrosis, elevated blood pressure, decreased plasma levels of L-arginine, and elevated L-ornithine. The HFHS diet or PA/HG treatment also induced increases in vascular arginase activity along with oxidative stress, reduced vascular NO levels, and impaired endothelial-dependent vasorelaxation. All of these effects except obesity and hypercholesterolemia were prevented or significantly reduced by endothelial-specific deletion of arginase 1 or ABH treatment. CONCLUSION Vascular dysfunctions in diet-induced obesity are prevented by deletion of arginase 1 in vascular endothelial cells or arginase inhibition. These findings indicate that upregulation of arginase 1 expression/activity in vascular endothelial cells has an integral role in diet-induced cardiovascular dysfunction and metabolic syndrome.
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MESH Headings
- Animals
- Arginase/antagonists & inhibitors
- Arginase/genetics
- Arginase/metabolism
- Arginine/blood
- Blood Glucose/metabolism
- Blood Pressure
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Experimental/prevention & control
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/physiopathology
- Diabetes Mellitus, Type 2/prevention & control
- Diet, High-Fat
- Dietary Sucrose
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Enzyme Inhibitors/pharmacology
- Fibrosis
- Genetic Predisposition to Disease
- Insulin/blood
- Male
- Metabolic Syndrome/enzymology
- Metabolic Syndrome/genetics
- Metabolic Syndrome/physiopathology
- Metabolic Syndrome/prevention & control
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/metabolism
- Obesity/drug therapy
- Obesity/enzymology
- Obesity/genetics
- Obesity/physiopathology
- Ornithine/blood
- Oxidative Stress
- Phenotype
- Signal Transduction
- Vascular Diseases/enzymology
- Vascular Diseases/genetics
- Vascular Diseases/physiopathology
- Vascular Diseases/prevention & control
- Vascular Stiffness/drug effects
- Vasodilation
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Affiliation(s)
- Anil Bhatta
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
| | - Lin Yao
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
- School of Pharmaceutical Sciences, South China Research Centre for
Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR
China
| | - Zhimin Xu
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
| | - Haroldo A. Toque
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
| | - Jijun Chen
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
| | - Reem T. Atawia
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
| | - Abdelrahman Y. Fouda
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
| | - Zsolt Bagi
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
- Department of Medicine, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
| | - Rudolf Lucas
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
| | - Ruth B. Caldwell
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta
University, Augusta, GA 30912, USA
- Veterans Administration Medical Centre, Augusta, GA 30912, USA
| | - Robert W. Caldwell
- Department of Pharmacology and Toxicology, Medical College of Georgia,
Augusta University, Augusta, GA 30912, USA
- Vascular Biology Centre, Medical College of Georgia, Augusta University,
Augusta, GA 30912, USA
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10
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Yao L, Bhatta A, Xu Z, Chen J, Toque HA, Chen Y, Xu Y, Bagi Z, Lucas R, Huo Y, Caldwell RB, Caldwell RW. Obesity-induced vascular inflammation involves elevated arginase activity. Am J Physiol Regul Integr Comp Physiol 2017; 313:R560-R571. [PMID: 28835451 PMCID: PMC5792147 DOI: 10.1152/ajpregu.00529.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 08/08/2017] [Accepted: 08/08/2017] [Indexed: 01/29/2023]
Abstract
Obesity-induced vascular dysfunction involves pathological remodeling of the visceral adipose tissue (VAT) and increased inflammation. Our previous studies showed that arginase 1 (A1) in endothelial cells (ECs) is critically involved in obesity-induced vascular dysfunction. We tested the hypothesis that EC-A1 activity also drives obesity-related VAT remodeling and inflammation. Our studies utilized wild-type and EC-A1 knockout (KO) mice made obese by high-fat/high-sucrose (HFHS) diet. HFHS diet induced increases in body weight, fasting blood glucose, and VAT expansion. This was accompanied by increased arginase activity and A1 expression in vascular ECs and increased expression of tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), interleukin-10 (IL-10), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) mRNA and protein in both VAT and ECs. HFHS also markedly increased circulating inflammatory monocytes and VAT infiltration by inflammatory macrophages, while reducing reparative macrophages. Additionally, adipocyte size and fibrosis increased and capillary density decreased in VAT. These effects of HFHS, except for weight gain and hyperglycemia, were prevented or reduced in mice lacking EC-A1 or treated with the arginase inhibitor 2-(S)-amino-6-boronohexanoic acid (ABH). In mouse aortic ECs, exposure to high glucose (25 mM) and Na palmitate (200 μM) reduced nitric oxide production and increased A1, TNF-α, VCAM-1, ICAM-1, and MCP-1 mRNA, and monocyte adhesion. Knockout of EC-A1 or ABH prevented these effects. HFHS diet-induced VAT inflammation is mediated by EC-A1 expression/activity. Limiting arginase activity is a possible therapeutic means of controlling obesity-induced vascular and VAT inflammation.
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Affiliation(s)
- Lin Yao
- School of Pharmaceutical Sciences, South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, People's Republic of China
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Anil Bhatta
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Zhimin Xu
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Jijun Chen
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Yongjun Chen
- South China Research Center for Acupuncture and Moxibustion, Guangzhou University of Chinese Medicine, Guangzhou, People's Republic of China
| | - Yimin Xu
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Zsolt Bagi
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Rudolf Lucas
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Yuqing Huo
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Ruth B Caldwell
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
- Department of Cell Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia
- Veterans Administration Medical Center, Augusta, Georgia; and
| | - R William Caldwell
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia;
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, Georgia
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11
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Toque HA, Fernandez-Flores A, Mohamed R, Caldwell RB, Ramesh G, Caldwell RW. Netrin-1 is a novel regulator of vascular endothelial function in diabetes. PLoS One 2017; 12:e0186734. [PMID: 29059224 PMCID: PMC5653335 DOI: 10.1371/journal.pone.0186734] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 10/08/2017] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Netrin-1, a secreted laminin-like protein identified as an axon guidance molecule, has been shown to be of critical importance in the cardiovascular system. Recent studies have revealed pro-angiogenic, anti-apoptotic and anti-inflammatory properties of netrin-1 as well as cardioprotective actions against myocardial injury in diabetic mice. AIM To examine the role of netrin-1 in diabetes-and high glucose (HG)-induced vascular endothelial dysfunction (VED) using netrin-1 transgenic mice (Tg3) and cultured bovine aortic endothelial cells (BAEC). MAIN OUTCOME Overexpression of netrin-1 prevented diabetes-induced VED in aorta from diabetic mice and netrin-1 treatment attenuated HG-induced impairment of nitric oxide synthase (NOS) function in BAECs. METHODS AND RESULTS Experiments were performed in Tg3 and littermate control (WT) mice rendered diabetic with streptozotocin (STZ) and in BAECs treated with HG (25 mmol/L). Levels of netrin-1 and its receptor DCC, markers of inflammation and apoptosis and vascular function were assessed in aortas from diabetic and non-diabetic Tg3 and WT mice. Vascular netrin-1 in WT mice was reduced under diabetic conditions. Aortas from non-diabetic Tg3 and WT mice showed similar maximum endothelium-dependent relaxation (MEDR) (83% and 87%, respectively). MEDR was markedly impaired in aorta from diabetic WT mice (51%). This effect was significantly blunted in Tg3 diabetic aortas (70%). Improved vascular relaxation in Tg3 diabetic mice was associated with increased levels of phospho-ERK1/2 and reduced levels of oxidant stress, NFκB, COX-2, p16INK4A, cleaved caspase-3 and p16 and p53 mRNA. Netrin-1 treatment prevented the HG-induced decrease in NO production and elevation of oxidative stress and apoptosis in BAECs. CONCLUSIONS Diabetes decreases aortic levels of netrin-1. However, overexpression of netrin-1 attenuates diabetes-induced VED and limits the reduction of NO levels, while increasing expression of p-ERK1/2, and suppressing oxidative stress and inflammatory and apoptotic processes. Enhancement of netrin-1 function may be a useful therapeutic means for preventing vascular dysfunction in diabetes.
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Affiliation(s)
- Haroldo A. Toque
- Department of Pharmacology & Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
- * E-mail:
| | - Aracely Fernandez-Flores
- Department of Pharmacology & Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Riyaz Mohamed
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - Ruth B. Caldwell
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
| | - Ganesan Ramesh
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
| | - R. William Caldwell
- Department of Pharmacology & Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States of America
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12
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Xu Y, Wang Y, Yan S, Yang Q, Zhou Y, Zeng X, Liu Z, An X, Toque HA, Dong Z, Jiang X, Fulton DJ, Weintraub NL, Li Q, Bagi Z, Hong M, Boison D, Wu C, Huo Y. Regulation of endothelial intracellular adenosine via adenosine kinase epigenetically modulates vascular inflammation. Nat Commun 2017; 8:943. [PMID: 29038540 PMCID: PMC5643397 DOI: 10.1038/s41467-017-00986-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/10/2017] [Indexed: 02/08/2023] Open
Abstract
The molecular mechanisms underlying vascular inflammation and associated inflammatory vascular diseases are not well defined. Here we show that endothelial intracellular adenosine and its key regulator adenosine kinase (ADK) play important roles in vascular inflammation. Pro-inflammatory stimuli lead to endothelial inflammation by increasing endothelial ADK expression, reducing the level of intracellular adenosine in endothelial cells, and activating the transmethylation pathway through increasing the association of ADK with S-adenosylhomocysteine (SAH) hydrolase (SAHH). Increasing intracellular adenosine by genetic ADK knockdown or exogenous adenosine reduces activation of the transmethylation pathway and attenuates the endothelial inflammatory response. In addition, loss of endothelial ADK in mice leads to reduced atherosclerosis and affords protection against ischemia/reperfusion injury of the cerebral cortex. Taken together, these results demonstrate that intracellular adenosine, which is controlled by the key molecular regulator ADK, influences endothelial inflammation and vascular inflammatory diseases. The molecular mechanisms underlying vascular inflammation are unclear. Here the authors show that pro-inflammatory stimuli lead to endothelial inflammation by increasing adenosine kinase expression, and that its knockdown in endothelial cells inhibits atherosclerosis and cerebral ischemic injury in mice.
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Affiliation(s)
- Yiming Xu
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA. .,School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436, China.
| | - Yong Wang
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,College of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Siyuan Yan
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Science, Beijing, 100101, China
| | - Qiuhua Yang
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Yaqi Zhou
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Xianqiu Zeng
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Zhiping Liu
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Xiaofei An
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.,Department of Endocrinology, Jiangsu Province Hospital of Chinese Medicine, Nanjing, 210029, China
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, USA
| | - Zheng Dong
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Xuejun Jiang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Science, Beijing, 100101, China
| | - David J Fulton
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Neal L Weintraub
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Qinkai Li
- Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Zsolt Bagi
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA
| | - Mei Hong
- Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Detlev Boison
- Robert S. Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, 97232, USA
| | - Chaodong Wu
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, 77840, USA
| | - Yuqing Huo
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA. .,Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. .,Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, USA.
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13
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Rojas M, Lemtalsi T, Toque HA, Xu Z, Fulton D, Caldwell RW, Caldwell RB. NOX2-Induced Activation of Arginase and Diabetes-Induced Retinal Endothelial Cell Senescence. Antioxidants (Basel) 2017; 6:antiox6020043. [PMID: 28617308 PMCID: PMC5488023 DOI: 10.3390/antiox6020043] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 05/30/2017] [Accepted: 06/09/2017] [Indexed: 12/19/2022] Open
Abstract
Increases in reactive oxygen species (ROS) and decreases in nitric oxide (NO) have been linked to vascular dysfunction during diabetic retinopathy (DR). Diabetes can reduce NO by increasing ROS and by increasing activity of arginase, which competes with nitric oxide synthase (NOS) for their commons substrate l-arginine. Increased ROS and decreased NO can cause premature endothelial cell (EC) senescence leading to defective vascular repair. We have previously demonstrated the involvement of NADPH oxidase 2 (NOX2)-derived ROS, decreased NO and overactive arginase in DR. Here, we investigated their impact on diabetes-induced EC senescence. Studies using diabetic mice and retinal ECs treated with high glucose or H2O2 showed that increases in ROS formation, elevated arginase expression and activity, and decreased NO formation led to premature EC senescence. NOX2 blockade or arginase inhibition prevented these effects. EC senescence was also increased by inhibition of NOS activity and this was prevented by treatment with a NO donor. These results indicate that diabetes/high glucose-induced activation of arginase and decreases in NO bioavailability accelerate EC senescence. NOX2-generated ROS contribute importantly to this process. Blockade of NOX2 or arginase represents a strategy to prevent diabetes-induced premature EC senescence by preserving NO bioavailability.
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Affiliation(s)
- Modesto Rojas
- Vascular Biology Center, Augusta University, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, USA.
- VA Medical Center, One Freedom Way, Augusta, GA 30904-6285, USA.
| | - Tahira Lemtalsi
- Vascular Biology Center, Augusta University, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, USA.
- VA Medical Center, One Freedom Way, Augusta, GA 30904-6285, USA.
| | - Haroldo A Toque
- Department of Pharmacology & Toxicology, Augusta University, 1459 Laney Walker, Boulevard, Augusta, GA 30912-2500, USA.
| | - Zhimin Xu
- Vascular Biology Center, Augusta University, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, USA.
- VA Medical Center, One Freedom Way, Augusta, GA 30904-6285, USA.
| | - David Fulton
- Vascular Biology Center, Augusta University, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, USA.
- Department of Pharmacology & Toxicology, Augusta University, 1459 Laney Walker, Boulevard, Augusta, GA 30912-2500, USA.
| | - Robert William Caldwell
- Department of Pharmacology & Toxicology, Augusta University, 1459 Laney Walker, Boulevard, Augusta, GA 30912-2500, USA.
| | - Ruth B Caldwell
- Vascular Biology Center, Augusta University, 1459 Laney Walker Boulevard, Augusta, GA 30912-2500, USA.
- VA Medical Center, One Freedom Way, Augusta, GA 30904-6285, USA.
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14
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Subramani K, Lu S, Warren M, Chu X, Toque HA, Caldwell RW, Diamond MP, Raju R. Mitochondrial targeting by dichloroacetate improves outcome following hemorrhagic shock. Sci Rep 2017; 7:2671. [PMID: 28572638 PMCID: PMC5453974 DOI: 10.1038/s41598-017-02495-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 04/12/2017] [Indexed: 12/16/2022] Open
Abstract
Hemorrhagic shock is a leading cause of death in people under the age of 45 and accounts for almost half of trauma-related deaths. In order to develop a treatment strategy based on potentiating mitochondrial function, we investigated the effect of the orphan drug dichloroacetate (DCA) on survival in an animal model of hemorrhagic shock in the absence of fluid resuscitation. Hemorrhagic shock was induced in rats by withdrawing 60% of the blood volume and maintaining a hypotensive state. The studies demonstrated prolonged survival of rats subjected to hemorrhagic injury (HI) when treated with DCA. In separate experiments, using a fluid resuscitation model we studied mitochondrial functional alterations and changes in metabolic networks connected to mitochondria following HI and treatment with DCA. DCA treatment restored cardiac mitochondrial membrane potential and tissue ATP in the rats following HI. Treatment with DCA resulted in normalization of several metabolic and molecular parameters including plasma lactate and p-AMPK/AMPK, as well as Ach-mediated vascular relaxation. In conclusion we demonstrate that DCA can be successfully used in the treatment of hemorrhagic shock in the absence of fluid resuscitation; therefore DCA may be a good candidate in prolonged field care following severe blood loss.
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Affiliation(s)
- Kumar Subramani
- Department of Laboratory Sciences, Augusta University, Augusta, GA, 30912, United States of America
| | - Sumin Lu
- Department of Laboratory Sciences, Augusta University, Augusta, GA, 30912, United States of America
| | - Marie Warren
- Department of Laboratory Sciences, Augusta University, Augusta, GA, 30912, United States of America
| | - Xiaogang Chu
- Department of Laboratory Sciences, Augusta University, Augusta, GA, 30912, United States of America
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, United States of America
| | - R William Caldwell
- Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, 30912, United States of America
| | - Michael P Diamond
- Department of Obstetrics and Gynaecology, Augusta University, Augusta, GA, 30912, United States of America
| | - Raghavan Raju
- Department of Laboratory Sciences, Augusta University, Augusta, GA, 30912, United States of America. .,Department of Surgery, Augusta University, Augusta, GA, 30912, United States of America. .,Department of Biochemistry and Molecular Biology, Augusta University, Augusta, GA, 30912, United States of America.
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15
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Bhatta A, Sangani R, Kolhe R, Toque HA, Cain M, Wong A, Howie N, Shinde R, Elsalanty M, Yao L, Chutkan N, Hunter M, Caldwell RB, Isales C, Caldwell RW, Fulzele S. Deregulation of arginase induces bone complications in high-fat/high-sucrose diet diabetic mouse model. Mol Cell Endocrinol 2016; 422:211-220. [PMID: 26704078 PMCID: PMC4824063 DOI: 10.1016/j.mce.2015.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/03/2015] [Accepted: 12/04/2015] [Indexed: 01/21/2023]
Abstract
A balanced diet is crucial for healthy development and prevention of musculoskeletal related diseases. Diets high in fat content are known to cause obesity, diabetes and a number of other disease states. Our group and others have previously reported that activity of the urea cycle enzyme arginase is involved in diabetes-induced dysregulation of vascular function due to decreases in nitric oxide formation. We hypothesized that diabetes may also elevate arginase activity in bone and bone marrow, which could lead to bone-related complications. To test this we determined the effects of diabetes on expression and activity of arginase, in bone and bone marrow stromal cells (BMSCs). We demonstrated that arginase 1 is abundantly present in the bone and BMSCs. We also demonstrated that arginase activity and expression in bone and bone marrow is up-regulated in models of diabetes induced by HFHS diet and streptozotocin (STZ). HFHS diet down-regulated expression of healthy bone metabolism markers (BMP2, COL-1, ALP, and RUNX2) and reduced bone mineral density, bone volume and trabecular thickness. However, treatment with an arginase inhibitor (ABH) prevented these bone-related complications of diabetes. In-vitro study of BMSCs showed that high glucose treatment increased arginase activity and decreased nitric oxide production. These effects were reversed by treatment with an arginase inhibitor (ABH). Our study provides evidence that deregulation of l-arginine metabolism plays a vital role in HFHS diet-induced diabetic complications and that these complications can be prevented by treatment with arginase inhibitors. The modulation of l-arginine metabolism in disease could offer a novel therapeutic approach for osteoporosis and other musculoskeletal related diseases.
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Affiliation(s)
- Anil Bhatta
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Rajnikumar Sangani
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA
| | - Ravindra Kolhe
- Departments of Pathology, Georgia Regents University, Augusta, GA 30912, USA
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Michael Cain
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA
| | - Abby Wong
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA
| | - Nicole Howie
- School of Dentistry, Georgia Regents University, Augusta, GA 30912, Augusta, GA 30912, USA
| | - Rahul Shinde
- Departments of Pathology, Georgia Regents University, Augusta, GA 30912, USA
| | - Mohammed Elsalanty
- School of Dentistry, Georgia Regents University, Augusta, GA 30912, Augusta, GA 30912, USA
| | - Lin Yao
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | | | - Monty Hunter
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA
| | - Ruth B Caldwell
- Cell Biology and Anatomy and Vascular Biology Center, Georgia Regents University; Charlie Norwood VA Medical Center, Augusta, GA 30912, USA
| | - Carlos Isales
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA; Institute of Regenerative and Reparative Medicine, Georgia Regents University, Augusta, GA 30912, USA
| | - R William Caldwell
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA.
| | - Sadanand Fulzele
- Departments of Orthopaedic Surgery, Georgia Regents University, Augusta, GA 30912, USA; Institute of Regenerative and Reparative Medicine, Georgia Regents University, Augusta, GA 30912, USA.
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16
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Caldwell RB, Toque HA, Narayanan SP, Caldwell RW. Arginase: an old enzyme with new tricks. Trends Pharmacol Sci 2015; 36:395-405. [PMID: 25930708 DOI: 10.1016/j.tips.2015.03.006] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/23/2015] [Accepted: 03/30/2015] [Indexed: 01/05/2023]
Abstract
Arginase has roots in early life-forms. It converts L-arginine to urea and ornithine. The former provides protection against NH3; the latter serves to stimulate cell growth and other physiological functions. Excessive arginase activity in mammals has been associated with cardiovascular and nervous system dysfunction and disease. Two relevant aspects of this elevated activity may be involved in these disease states. First, excessive arginase activity reduces the supply of L-arginine needed by nitric oxide (NO) synthase to produce NO. Second, excessive production of ornithine leads to vascular structural problems and neural toxicity. Recent research has identified inflammatory agents and reactive oxygen species (ROS) as drivers of this pathologic elevation of arginase activity and expression. We review the involvement of arginase in cardiovascular and nervous system dysfunction, and discuss potential therapeutic interventions targeting excess arginase.
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Affiliation(s)
- Ruth B Caldwell
- Veterans Affairs Medical Center, One Freedom Way, Augusta, GA 30904, USA; Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA; Vascular Biology Center, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA.
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA
| | - S Priya Narayanan
- Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA; Vascular Biology Center, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA; Department of Occupational Therapy, School of Allied Health Sciences, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA
| | - R William Caldwell
- Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA; Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA.
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17
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Bhatta A, Yao L, Toque HA, Shatanawi A, Xu Z, Caldwell RB, Caldwell RW. Correction: angiotensin II-induced arterial thickening, fibrosis and stiffening involves elevated arginase function. PLoS One 2015; 10:e0127110. [PMID: 25898276 PMCID: PMC4405341 DOI: 10.1371/journal.pone.0127110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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18
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Nunes KP, Teixeira CE, Priviero FBM, Toque HA, Webb RC. Beneficial effect of the soluble guanylyl cyclase stimulator BAY 41-2272 on impaired penile erection in db/db-/- type II diabetic and obese mice. J Pharmacol Exp Ther 2015; 353:330-9. [PMID: 25740897 DOI: 10.1124/jpet.114.220970] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Type 2 diabetes mellitus (DM2) and obesity are major risk factors for erectile dysfunction (ED). In diabetes, increased oxidative stress leads to decreased nitric oxide (NO) bioavailability, and diabetic patients appear to be less responsive to conventional therapy with phosphodiesterase type 5 inhibitors. We investigated whether the soluble guanylyl cyclase stimulator BAY 41-2272 (5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4ylamine) is effective in improving impaired corpus cavernosum (CC) relaxation in obese DM2 mice by reducing oxidative stress. Adult db/db(-/-) mice or their lean db(/+) littermates were used to assess vascular function, cGMP levels, antioxidant status, NADPH oxidase expression, and superoxide formation in the absence or presence of BAY 41-2272. Results showed that BAY 41-2272 (10(-8) to 10(-5) M) potently relaxed CC from db(/+) or db/db(-/-) mice in a similar manner. BAY 41-2272 significantly enhanced both endothelium-dependent and nitrergic relaxation induced by electrical field stimulation (EFS), and improved the impaired relaxation to acetylcholine and EFS in the diabetic animals in a concentration-dependent manner (10(-8) to 10(-7) M). BAY 41-2272 increased cGMP levels and potentiated relaxation responses to exogenous NO in CC. Total antioxidant status was reduced in plasma and urine whereas expression of vascular NADPH oxidase subunits (gp91phox, p22phox, and p47phox) was increased in the CC of db/db(-/-) mice, suggesting a state of oxidative stress. These effects were prevented by BAY 41-2272 in a concentration-dependent manner. These results suggest that BAY 41-2272 improves CC relaxation in db/db(-/-) mice by increasing cGMP and augmenting antioxidant status, making this drug is a potential novel candidate to treat ED.
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Affiliation(s)
- Kenia Pedrosa Nunes
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Cleber E Teixeira
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Fernanda B M Priviero
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Haroldo A Toque
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - R Clinton Webb
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
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Silva FH, Lanaro C, Leiria LO, Rodrigues RL, Davel AP, Claudino MA, Toque HA, Antunes E. Oxidative stress associated with middle aging leads to sympathetic hyperactivity and downregulation of soluble guanylyl cyclase in corpus cavernosum. Am J Physiol Heart Circ Physiol 2014; 307:H1393-400. [DOI: 10.1152/ajpheart.00708.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Impairment of nitric oxide (NO)-mediated cavernosal relaxations in middle age contributes to erectile dysfunction. However, little information is available about the alterations of sympathetic neurotransmission and contraction in erectile tissue at middle age. This study aimed to evaluate the alterations of the contractile machinery associated with tyrosine hydroxylase (TH) in rat corpus cavernosum (RCC) at middle age, focusing on the role of superoxide anion. Male Wistar young (3.5-mo) and middle-aged (10-mo) rats were used. Electrical-field stimulation (EFS)- and phenylephrine-induced contractions were obtained in RCC strips. Levels of reactive-oxygen species (ROS) and TH mRNA expression, as well as protein expressions for α1/β1-subunits of soluble guanylyl cyclase (sGC), in RCC were evaluated. The neurogenic contractile responses elicited by EFS (4–32 Hz) were greater in RCC from the middle-aged group that was accompanied by elevated TH mRNA expression ( P < 0.01). Phenylephrine-induced contractions were also greater in the middle-aged group. A 62% increase in ROS generation in RCC from middle-aged rats was observed. The mRNA expression for the α1A-adrenoceptor remained unchanged among groups. Protein levels of α1/β1-sGC subunits were decreased in RCC from the middle-aged compared with young group. The NADPH oxidase inhibitor apocynin (85 mg·rat−1·day−1, 4 wk) fully restored the enhanced ROS production, TH mRNA expressions, and α1/β1-subunit sGC expression, indicating that excess of superoxide anion plays a major role in the sympathetic hyperactivity and hypercontractility in erectile tissue at middle age. Reduction of oxidative stress by dietary antioxidants may be an interesting approach to treat erectile dysfunction in aging population.
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Affiliation(s)
- Fábio H. Silva
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Carolina Lanaro
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Luiz Osório Leiria
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Renata Lopes Rodrigues
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Ana Paula Davel
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Mário A. Claudino
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
| | - Haroldo A. Toque
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, Georgia
| | - Edson Antunes
- Department of Pharmacology, Faculty of Medical Sciences and Department of Anatomy, Cellular Biology, Physiology and Biophysics, Institute of Biology, University of Campinas, Campinas, São Paulo, Brazil; and
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Wang L, Bhatta A, Toque HA, Rojas M, Yao L, Xu Z, Patel C, Caldwell RB, Caldwell RW. Arginase inhibition enhances angiogenesis in endothelial cells exposed to hypoxia. Microvasc Res 2014; 98:1-8. [PMID: 25445030 DOI: 10.1016/j.mvr.2014.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 10/29/2014] [Accepted: 11/02/2014] [Indexed: 10/24/2022]
Abstract
Hypoxia-induced arginase elevation plays an essential role in several vascular diseases but influence of arginase on hypoxia-mediated angiogenesis is completely unknown. In this study, in vitro network formation in bovine aortic endothelial cells (BAEC) was examined after exposure to hypoxia for 24h with or without arginase inhibition. Arginase activity, protein levels of the two arginase isoforms, eNOS, and VEGF as well as production of NO and ROS were examined to determine the involvement of arginase in hypoxia-mediated angiogenesis. Hypoxia elevated arginase activity and arginase 2 expression but reduced active p-eNOS(Ser1177) and NO levels in BAEC. In addition, both VEGF protein levels and endothelial elongation and network formation were reduced with continued hypoxia, whereas ROS levels increased and NO levels decreased. Arginase inhibition limited ROS, restored NO formation and VEGF expression, and prevented the reduction of angiogenesis. These results suggest a fundamental role of arginase activity in regulating angiogenic function.
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Affiliation(s)
- Lin Wang
- Department of Plastic Surgery, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, PR China; Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Anil Bhatta
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Haroldo A Toque
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Modesto Rojas
- Vascular Biology Center, Georgia Regents University, Charlie Norwood VA Medical Center, Augusta GA, 30912, USA
| | - Lin Yao
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA
| | - Zhimin Xu
- Vascular Biology Center, Georgia Regents University, Charlie Norwood VA Medical Center, Augusta GA, 30912, USA
| | - Chintan Patel
- Vascular Biology Center, Georgia Regents University, Charlie Norwood VA Medical Center, Augusta GA, 30912, USA
| | - Ruth B Caldwell
- Vascular Biology Center, Georgia Regents University, Charlie Norwood VA Medical Center, Augusta GA, 30912, USA
| | - R William Caldwell
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, GA 30912, USA.
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Chen YJ, Liu YL, Zhong Q, Yu YF, Su HL, Toque HA, Dang YH, Chen F, Xu M, Chen T. Tetrahydropalmatine protects against methamphetamine-induced spatial learning and memory impairment in mice. Neurosci Bull 2014; 28:222-32. [PMID: 22622821 DOI: 10.1007/s12264-012-1236-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE The purpose of this study was to investigate the effect of methamphetamine (MA) on spatial learning and memory and the role of tetrahydropalmatine (THP) in MA-induced changes in these phenomena in mice. METHODS Male C57BL/6 mice were randomly divided into eight groups, according to different doses of MA, different doses of THP, treatment with both MA and THP, and saline controls. Spatial learning and memory were assessed using the Morris water maze. Western blot was used to detect the expression of extracellular signal-regulated protein kinase (ERK) in the mouse prefrontal cortex (PFC) and hippocampus. RESULTS Repeated MA treatment significantly increased the escape latency in the learning phase and decreased the number of platform site crossings in the memory-test phase. ERK1/2 expression was decreased in the PFC but not in the hippocampus of the MA-treated mice. Repeated THP treatment alone did not affect the escape latency, the number of platform site crossings or the total ERK1/2 expression in the brain. Statistically significantly shorter escape latencies and more platform site crossings occurred in MA+THP-treated mice than in MA-treated mice. CONCLUSION Repeated MA administration impairs spatial learning and memory in mice, and its co-administration with THP prevents this impairment, which is probably attributable to changed ERK1/2 expression in the PFC. This study contributes to uncovering the mechanism underlying MA abuse, and to exploring potential therapies.
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Affiliation(s)
- Yan-Jiong Chen
- Department of Immunology and Pathogenic Biology, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
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Rojas M, Zhang W, Xu Z, Lemtalsi T, Chandler P, Toque HA, Caldwell RW, Caldwell RB. Requirement of NOX2 expression in both retina and bone marrow for diabetes-induced retinal vascular injury. PLoS One 2013; 8:e84357. [PMID: 24358357 PMCID: PMC3866146 DOI: 10.1371/journal.pone.0084357] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 11/14/2013] [Indexed: 12/11/2022] Open
Abstract
Objective Diabetic retinopathy, a major cause of blindness, is characterized by increased expression of vascular endothelial growth factor (VEGF), leukocyte attachment to the vessel walls and increased vascular permeability. Previous work has shown that reactive oxygen species (ROS) produced by the superoxide generating enzyme NOX2/NADPH oxidase play a crucial role in the vascular pathology. The aim of this work was to identify the cellular sources of the damaging NOX2 activity by studies using bone marrow chimera mice. Methods Bone marrow cells were collected from the femurs and tibias of wild type and NOX2 deficient (NOX2-/-) donor mice and injected intravenously into lethally irradiated NOX2-/- and wild type recipients. Following recovery from radiation, mice were rendered diabetic by streptozotocin injections. The following groups of bone marrow chimeras were studied: non-diabetic WT→WT, diabetic WT→WT, diabetic WT→NOX2-/-, diabetic NOX2-/-→WT. After 4 weeks of diabetes, early signs of retinopathy were examined by measuring ROS, expression of VEGF and ICAM-1, leukocyte attachment to the vessel wall and vascular permeability. Results The retinas of the diabetic WT→WT chimeras showed significant increases in ROS as compared with the non-diabetic chimeras. These diabetes-induced alterations were correlated with increases in expression of VEGF and ICAM-1, leukocyte adhesion and vascular permeability. Each of these diabetes-induced alterations were significantly attenuated in the diabetic WT→NOX2-/- and NOX2-/-→WT chimera groups (p<0.05). Conclusion NOX2-generated ROS produced by both bone marrow-derived cells and resident retinal cells contribute importantly to retinal vascular injury in the diabetic retina. Targeting NOX2 in bone marrow and/or retinal cells may represent a novel therapeutic strategy for the treatment/prevention of vascular injury in the diabetic retina.
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Affiliation(s)
- Modesto Rojas
- VA Medical Center, Augusta, Georgia, United States of America
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Wenbo Zhang
- VA Medical Center, Augusta, Georgia, United States of America
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Zhimin Xu
- VA Medical Center, Augusta, Georgia, United States of America
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Tahira Lemtalsi
- VA Medical Center, Augusta, Georgia, United States of America
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Phillip Chandler
- Immunotherapy Center, Georgia Reagents University, Augusta, Georgia, United States of America
| | - Haroldo A. Toque
- Department of Pharmacology & Toxicology, Georgia Reagents University, Augusta, Georgia, United States of America
| | - Robert W. Caldwell
- Department of Pharmacology & Toxicology, Georgia Reagents University, Augusta, Georgia, United States of America
| | - Ruth B. Caldwell
- VA Medical Center, Augusta, Georgia, United States of America
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
- * E-mail:
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Narayanan SP, Rojas M, Suwanpradid J, Toque HA, Caldwell RW, Caldwell RB. Arginase in retinopathy. Prog Retin Eye Res 2013; 36:260-80. [PMID: 23830845 PMCID: PMC3759622 DOI: 10.1016/j.preteyeres.2013.06.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/14/2013] [Accepted: 06/25/2013] [Indexed: 12/12/2022]
Abstract
Ischemic retinopathies, such as diabetic retinopathy (DR), retinopathy of prematurity and retinal vein occlusion are a major cause of blindness in developed nations worldwide. Each of these conditions is associated with early neurovascular dysfunction. However, conventional therapies target clinically significant macula edema or neovascularization, which occur much later. Intra-ocular injections of anti-VEGF show promise in reducing retinal edema, but the effects are usually transient and the need for repeated injections increases the risk of intraocular infection. Laser photocoagulation can control pathological neovascularization, but may impair vision and in some patients the retinopathy continues to progress. Moreover, neither treatment targets early stage disease or promotes repair. This review examines the potential role of the ureahydrolase enzyme arginase as a therapeutic target for the treatment of ischemic retinopathy. Arginase metabolizes l-arginine to form proline, polyamines and glutamate. Excessive arginase activity reduces the l-arginine supply for nitric oxide synthase (NOS), causing it to become uncoupled and produce superoxide and less NO. Superoxide and NO react and form the toxic oxidant peroxynitrite. The catabolic products of polyamine oxidation and glutamate can induce more oxidative stress and DNA damage, both of which can cause cellular injury. Studies indicate that neurovascular injury during retinopathy is associated with increased arginase expression/activity, decreased NO, polyamine oxidation, formation of superoxide and peroxynitrite and dysfunction and injury of both vascular and neural cells. Furthermore, data indicate that the cytosolic isoform arginase I (AI) is involved in hyperglycemia-induced dysfunction and injury of vascular endothelial cells whereas the mitochondrial isoform arginase II (AII) is involved in neurovascular dysfunction and death following hyperoxia exposure. Thus, we postulate that activation of the arginase pathway causes neurovascular injury by uncoupling NOS and inducing polyamine oxidation and glutamate formation, thereby reducing NO and increasing oxidative stress, all of which contribute to the retinopathic process.
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Affiliation(s)
- S. Priya Narayanan
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Modesto Rojas
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Jutamas Suwanpradid
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Haroldo A. Toque
- Department of Pharmacology & Toxicology, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - R. William Caldwell
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Department of Pharmacology & Toxicology, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
| | - Ruth B. Caldwell
- Vision Discovery Institute, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- Vascular Biology Center, Georgia Regents University, 1459 Laney Walker Boulevard, Augusta, 30912, USA
- VA Medical Center, One Freedom Way, Augusta, GA, USA
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Toque HA, Nunes KP, Yao L, Xu Z, Kondrikov D, Su Y, Webb RC, Caldwell RB, Caldwell RW. Akita spontaneously type 1 diabetic mice exhibit elevated vascular arginase and impaired vascular endothelial and nitrergic function. PLoS One 2013; 8:e72277. [PMID: 23977269 PMCID: PMC3747112 DOI: 10.1371/journal.pone.0072277] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 07/15/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Elevated arginase (Arg) activity is reported to be involved in diabetes-induced vascular endothelial dysfunction. It can reduce L-arginine availability to nitric oxide (NO) synthase (NOS) and NO production. Akita mice, a genetic non-obese type 1 diabetes model, recapitulate human diabetes. We determined the role of Arg in a time-course of diabetes-associated endothelial dysfunction in aorta and corpora cavernosa (CC) from Akita mice. METHODS AND RESULTS Endothelium-dependent relaxation, Arg and NOS activity, and protein expression levels of Arg and constitutive NOS were assessed in aortas and CC from Akita and non-diabetic wild type (WT) mice at 4, 12 and 24 wks of age. Systolic blood pressure (SBP) was assessed by tail cuff. In aorta and CC, Akita mice exhibited a progressive impairment of vascular endothelial and nitrergic function increased Arg activity and expression (Arg1 in aorta and both Arg1 and Arg2 in CC) compared with that of age-matched WT mice. Treatment of aorta and CC from Akita mice with an Arg inhibitor (BEC or ABH) reduced diabetes-induced elevation of Arg activity and restored endothelial and nitrergic function. Reduced levels of phospho-eNOS at Ser(1177) (in aorta and CC) and nNOS expression (in CC) were observed in Akita mice at 12 and 24 wks. Akita mice also had decreased NOS activity in aorta and CC at 12 and 24 wks that was restored by BEC treatment. Further, Akita mice exhibited moderately increased SBP at 24 wks and increased sensitivity to PE-induced contractions in aorta and sympathetic nerve stimulation in CC at 12 and 24 wks. CONCLUSIONS Over 24 wks of diabetes in Akita mice, both aortic and cavernosal tissues exhibited increased Arg activity/expression, contributing to impaired endothelial and nitrergic function and reduced NO production. Our findings demonstrate involvement of Arg activity in diabetes-induced impairment of vascular function in Akita mouse.
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Affiliation(s)
- Haroldo A Toque
- Department of Pharmacology and Toxicology, Georgia Regents University, Augusta, Georgia, United States of America.
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Toque HA, Nunes KP, Rojas M, Bhatta A, Yao L, Xu Z, Romero MJ, Webb RC, Caldwell RB, Caldwell RW. Arginase 1 mediates increased blood pressure and contributes to vascular endothelial dysfunction in deoxycorticosterone acetate-salt hypertension. Front Immunol 2013; 4:219. [PMID: 23908657 PMCID: PMC3725429 DOI: 10.3389/fimmu.2013.00219] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/15/2013] [Indexed: 11/23/2022] Open
Abstract
Enhanced arginase (ARG) activity has been identified as a factor that reduces nitric oxide production and impairs endothelial function in vascular pathologies. Using a gene deletion model, we investigated involvement of arginase isoforms arginase 1 and 2 (ARG1 and ARG2) in hypertension and endothelial dysfunction in a mineralocorticoid-salt mouse model. Hypertension was induced in wild type (WT), partial ARG1+/− knockout (KO), and complete ARG2−/− KO mice by uninephrectomy and deoxycorticosterone acetate (DOCA)-salt treatment for 6-weeks. (Control uninephrectomized mice drank tap water.) After 2 weeks of DOCA-salt treatment, systolic blood pressure (SBP) was increased by ∼15 mmHg in all mouse genotypes. SBP continued to rise in DOCA-salt WT and ARG2−/− mice to ∼130 mmHg at 5–6 weeks, whereas in ARG1+/− mice SBP waned toward control levels by 6 weeks (109 ± 4 vs. 101 ± 3 mmHg, respectively). DOCA-salt treatment in WT mice increased vascular ARG activity (aorta by 1.5-fold; mesenteric artery (MA) by 2.6-fold and protein levels of ARG1 (aorta: 1.49-fold and MA: 1.73-fold) vs. WT Sham tissues. ARG2 protein increased in WT-DOCA MA (by 2.15-fold) but not in aorta compared to those of WT Sham tissues. Maximum endothelium-dependent vasorelaxation to acetylcholine was significantly reduced in DOCA-salt WT mice and largely or partially maintained in DOCA ARG1+/− and ARG2−/− mice vs. their Sham controls. DOCA-salt augmented contractile responses to phenylephrine in aorta of all mouse genotypes. Additionally, treatment of aorta or MA from WT-DOCA mice with arginase inhibitor (100 μM) improved endothelium-mediated vasorelaxation. DOCA-salt-induced coronary perivascular fibrosis (increased by 2.1-fold) in WT was prevented in ARG1+/− and reduced in ARG2−/− mice. In summary, ARG is involved in murine DOCA-salt-induced impairment of vascular function and hypertension and may represent a novel target for antihypertensive therapy.
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Affiliation(s)
- Haroldo A Toque
- Department of Pharmacology and Toxicology, Georgia Regents University , Augusta, GA , USA
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Toque HA, Nunes KP, Yao L, Liao JK, Webb RC, Caldwell RB, Caldwell RW. Activated Rho kinase mediates diabetes-induced elevation of vascular arginase activation and contributes to impaired corpora cavernosa relaxation: possible involvement of p38 MAPK activation. J Sex Med 2013; 10:1502-15. [PMID: 23566117 DOI: 10.1111/jsm.12134] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Activated RhoA/Rho kinase (ROCK) has been implicated in diabetes-induced erectile dysfunction. Earlier studies have demonstrated involvement of ROCK pathway in the activation of arginase in endothelial cells. However, signaling pathways activated by ROCK in the penis remain unclear. AIM We tested whether ROCK and p38 MAPK are involved in the elevation of arginase activity and subsequent impairment of corpora cavernosal (CC) relaxation in diabetes. METHODS Eight weeks after streptozotocin-induced diabetes, vascular functional studies, arginase activity assay, and protein expression of RhoA, ROCK, phospho-p38 MAPK, p38 MAPK, phospho-MYPT-1(Thr850), MYPT-1 and arginase levels were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT + D), partial ROCK 2(+/-) knockout (KO), and ROCK 2(+/-) KO + D mice. MAIN OUTCOME MEASURES The expression of RhoA, ROCK 1 and 2, phosphorylation of MYPT-1(Thr850) and p38 MAPK, arginase activity/expression, endothelial- and nitrergic-dependent relaxation of CC was assayed. RESULTS Diabetes significantly reduced maximum relaxation (Emax ) to both endothelium-dependent acetylcholine (WT + D: Emax; 61 ± 4% vs. WT: Emax; 75 ± 2%) and nitrergic nerve stimulation. These effects were associated with increased expression of active RhoA, ROCK 2, phospho-MYPT-1(Thr850), phospho-p38 MAPK, arginase II, and activity of corporal arginase (1.6-fold) in WT diabetic CC. However, this impairment in CC of WT + D mice was absent in heterozygous ROCK 2(+/-) KO + D mice for acetylcholine (Emax : 80 ± 5%) and attenuated for nitrergic nerve-induced relaxation. CC of ROCK 2(+/-) KO + D mice showed much less ROCK activity, did not exhibit p38 MAPK activation, and had reduced arginase activity and arginase II expression. These findings indicate that ROCK 2 mediates diabetes-induced elevation of arginase activity. Additionally, pretreatment of WT diabetic CC with inhibitors of arginase (ABH) or p38 MAPK (SB203580) partially prevented impairment of ACh- and nitrergic nerve-induced relaxation and elevation of arginase activity. CONCLUSION ROCK 2, p38 MAPK and arginase play key roles in diabetes-induced impairment of CC relaxation.
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Affiliation(s)
- Haroldo A Toque
- Department of Pharmacology & Toxicology, Georgia Health Sciences University, Augusta, GA 30912-2300, USA.
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Bhatta A, Toque HA, Caldwell RB, Caldwell RW. Diabetes/high glucose induced arginase increases arterial smooth muscle cell proliferation and collagen synthesis/fibrosis through ornithine decarboxylase and ornithine aminotransferase pathways. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.651.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Anil Bhatta
- Pharmacology and ToxicologyGeorgia Health Sciences UniversityAugustaGA
| | - Haroldo A Toque
- Pharmacology and ToxicologyGeorgia Health Sciences UniversityAugustaGA
| | - Ruth B Caldwell
- Vascular Biology CenterGeorgia Health Sciences UniversityAugustaGA
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Elms SC, Toque HA, Rojas M, Xu Z, Caldwell RW, Caldwell RB. The role of arginase I in diabetes-induced retinal vascular dysfunction in mouse and rat models of diabetes. Diabetologia 2013; 56:654-62. [PMID: 23232640 PMCID: PMC3565067 DOI: 10.1007/s00125-012-2789-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 11/07/2012] [Indexed: 10/27/2022]
Abstract
AIMS/HYPOTHESIS A reduction in retinal blood flow occurs early in diabetes and is likely to be involved in the development of diabetic retinopathy. We hypothesise that activation of the arginase pathway could have a role in the vascular dysfunction of diabetic retinopathy. METHODS Experiments were performed using a mouse and rat model of streptozotocin (STZ)-induced diabetes for in vivo and ex vivo analysis of retinal vascular function. For in vivo studies, mice were infused with the endothelial-dependent vasodilator acetylcholine (ACh) or the endothelial-independent vasodilator sodium nitroprusside (SNP), and vasodilation was assessed using a fundus microscope. Ex vivo assays included pressurised vessel myography, western blotting and arginase activity measurements. RESULTS ACh-induced retinal vasodilation was markedly impaired in diabetic mice (40% of control values), whereas SNP-induced dilation was not altered. The diabetes-induced vascular dysfunction was markedly blunted in mice lacking one copy of the gene encoding arginase I and in mice treated with the arginase inhibitor 2(S)-amino-6-boronohexanoic acid. Ex vivo studies performed using pressure myography and central retinal arteries isolated from rats with STZ-induced diabetes showed a similar impairment of endothelial-dependent vasodilation that was partially blunted by pretreatment of the isolated vessels with another arginase inhibitor, (S)-2-boronoethyl-L-cysteine. The diabetes-induced vascular alterations were associated with significant increases in both arginase I protein levels and total arginase activity. CONCLUSIONS/INTERPRETATION These results indicate that, in the mouse and rat model, diabetes-induced increases in arginase I were involved in the diabetes-induced impairment of retinal blood flow by a mechanism involving vascular endothelial cell dysfunction.
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Affiliation(s)
- S C Elms
- Vascular Biology Center, Georgia Health Sciences University, 1459 Laney Walker Boulevard, Augusta, GA 30912, USA
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30
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Silva FH, Mónica FZ, Báu FR, Brugnerotto AF, Priviero FBM, Toque HA, Antunes E. Superoxide anion production by NADPH oxidase plays a major role in erectile dysfunction in middle-aged rats: prevention by antioxidant therapy. J Sex Med 2013; 10:960-71. [PMID: 23347406 DOI: 10.1111/jsm.12063] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION.: Prevalence of erectile dysfunction (ED) increases progressively with aging, but the ED pathophysiology at its early stages is still poorly investigated. AIM.: This study aimed to evaluate the functional and molecular alterations of erectile function at middle age, focusing on the contribution of oxidative stress in erectile tissue for the ED. METHODS.: Young (3.5-month) and middle-aged (10-month) male Wistar rats were used. Rat corpus cavernosum (RCC) was dissected free and mounted in 10-mL organ baths containing Krebs solution. Intracavernosal pressure (ICP) in anesthetized rats was evaluated. MAIN OUTCOME MEASURES.: Concentration-response curves to endothelium-dependent and endothelium-independent agents, as well as to electrical field stimulation (EFS), were obtained in RCC strips. Measurement of cyclic guanosine monophosphate (cGMP) and expressions of neuronal nitric oxide synthase (nNOS) and endothelial NOS (eNOS), gp91(phox) and superoxide dismutase-1 (SOD-1) expressions in RCC were evaluated. RESULTS.: ICP was significantly reduced in middle-aged compared with young rats. RCC relaxations to acetylcholine (10(-8) to 10(-2) M), sodium nitroprusside (10(-8) to 10(-2) M), sildenafil (10(-9) to 10(-5) M), BAY 41-2272 (10(-9) to 10(-5) M), and EFS (4-32 Hz) were decreased in middle-aged group, which were nearly normalized by apocynin (NADPH oxidase inhibitor; 10(-4) M) or SOD (75 U/mL). Prolonged treatment with apocynin (85 mg/rat/day, 4 weeks) also restored the impaired relaxations in middle-aged rats. Relaxations to 8-bromoguanosine 3',5'-cyclic monophosphate sodium salt (8-Br-cGMP; 10(-8) to 3 × 10(-4) M) remained unchanged between groups. Basal and stimulated cGMP production were lower in middle-aged group, an effect fully restored by apocynin and SOD. Protein expression of nNOS and phosphorylated eNOS (p-eNOS) (Ser-1177) reduced, whereas gp(91phox) mRNA expression increased in RCC from middle-aged rats. CONCLUSIONS.: ED in middle-aged rats is associated with decreased NO bioavailability in erectile tissue due to upregulation of NADPH oxidase subunit gp91(phox) and downregulation of nNOS/p-eNOS. Antioxidant therapies may be a good pharmacological approach to prevent ED at its early stages.
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Affiliation(s)
- Fábio H Silva
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas, Campinas, SP, Brazil
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31
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Yao L, Chandra S, Toque HA, Bhatta A, Rojas M, Caldwell RB, Caldwell RW. Prevention of diabetes-induced arginase activation and vascular dysfunction by Rho kinase (ROCK) knockout. Cardiovasc Res 2012; 97:509-19. [PMID: 23250919 DOI: 10.1093/cvr/cvs371] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS We determined the role of the Rho kinase (ROCK) isoforms in diabetes-induced vascular endothelial dysfunction and enhancement of arginase activity and expression. METHODS AND RESULTS Studies were performed in aortic tissues from haplo-insufficient (H-I) ROCK1 and ROCK2 mice and wild-type (WT) mice rendered diabetic with streptozotocin and in bovine aortic endothelial cells (BAECs) treated with high glucose (HG, 25 mM). Protein expression of both ROCK isoforms was substantially elevated in aortas of WT mice after 8 weeks of diabetes and in BAECs after 48 h in HG. Impairment of endothelium-dependent vasorelaxation of aortas was observed in diabetic WT mice. However, there was no impairment in aortas of diabetic ROCK1 H-I mice and less impairment in aortas of diabetic ROCK2 H-I mice, compared with non-diabetic mice. These vascular effects were associated with the prevention of diabetes-induced decrease in nitric oxide (NO) production and a rise in arginase activity/expression. Acute treatment with the arginase inhibitor, BEC, improved endothelium-dependent vasorelaxation of aortas of both diabetic WT and ROCK2, but not of ROCK1 mice. CONCLUSION Partial deletion of either ROCK isoform, but to a greater extent ROCK1, attenuates diabetes-induced vascular endothelial dysfunction by preventing increased arginase activity and expression and reduction in NO production in type 1 diabetes. Limiting ROCK and arginase activity improves vascular function in diabetes.
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Affiliation(s)
- Lin Yao
- Department of Pharmacology and Toxicology, Georgia Health Sciences University, Augusta, GA 30912-2300, USA
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32
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Toque HA, Nunes KP, yao L, Bhatta A, Anea CB, Rudic RD, Webb RC, Caldwell RB, Caldwell RW. Abstract 270: Arginase I Deletion Blocks Age-Related Enhancement of Vascular Stiffness and Endothelial Dysfunction. Hypertension 2012. [DOI: 10.1161/hyp.60.suppl_1.a270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular stiffening, decreased nitric oxide (NO) bioavailability and vascular endothelial dysfunction (ED) are markers of the aging cardiovascular system. Increased vascular stiffness and ED are predictors for adverse cardiovascular outcomes. Increased vascular arginase activity has been noted to accompany aging-induced endothelial dysfunction (ED). Therefore, we hypothesized that enhanced arginase activity is involved in age-related increases in arterial stiffness and ED and that limiting the activity of arginase I (Arg I) would reduce this pathology. We tested this hypothesis by analysis of vascular stiffness and ED in aortas from old (12-month) and young (3-month) male wild type (WT) mice and mice lacking one copy of arginase I (Arg I
+/-
KO).
In vivo
studies measured vascular stiffness by pulse wave velocity (PWV) and systolic blood pressure (SBP) by tail cuff. Vascular endothelial function studies also were performed
ex vivo
using myography. Arginase activity assay showed that activity in the aged WT mice was 1.47-fold greater than that in the young WT mice. PWV was markedly increased in old WT mice (1.96±0.28 m/s) compared to young WT mice (1.08±0.10 m/s). By contrast, PWV remained normal in old Arg I
+/-
KO mice (1.15±0.08 m/s). Endothelium (NO)-dependent vasorelaxation to acetylcholine (ACh) was significantly reduced in the old WT mice as compared with young WT mice (maximum relaxation (MR) of 60±3%
vs
78±4%, respectively). This age-induced impairment was markedly blunted in aged Arg I
+/-
KO mice (MR: 71±3%). The arginase inhibitor BEC (100 μM) also reversed the impairment in ACh-induced vasorelaxation in old WT mice (P<0.05). No differences were observed in endothelial-independent relaxation to SNP among the groups. SBP was also unchanged. In conclusion, deletion of one copy of Arg I prevents ED and reduces vascular stiffness in aging. Thus, reduction of arginase I function may serve as a therapeutic target for normalizing arterial stiffness and preventing vascular dysfunction in aging.
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Affiliation(s)
| | | | - Lin yao
- Georgia Health Sciences Univ, Augusta, GA
| | | | | | - R. D Rudic
- Georgia Health Sciences Univ, Augusta, GA
| | - R. C Webb
- Georgia Health Sciences Univ, Augusta, GA
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Nunes KP, Toque HA, Borges MH, Richardson M, Webb RC, de Lima ME. Erectile function is improved in aged rats by PnTx2-6, a toxin from Phoneutria nigriventer spider venom. J Sex Med 2012; 9:2574-81. [PMID: 22925420 DOI: 10.1111/j.1743-6109.2012.02878.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Age-associated erectile dysfunction (ED) involves a decrease in nitric oxide (NO) availability and impaired relaxation. PnTx2-6, a toxin from the Phoneutria nigriventer spider, has been demonstrated to improve erectile function via NO/cyclic guanosine monophosphate (cGMP) pathway. This spider's venom is characterized by several symptoms, including erection. PnTx2-6 has been implicated in this phenomenon. Animal venoms have been postulated as potential drugs to treat ED. AIM PnTx2-6 toxin improves erectile function in aged rats via NO/cGMP. We investigated the effect of PnTx2-6 in the erectile function of aged rats. MAIN OUTCOME MEASURES ED was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio during electrical field stimulation (EFS) of the pelvic ganglion of aged and adult rats (70 vs. 14 weeks). In functional studies, EFS-induced relaxation of corpus cavernosum (CC) strips were performed with or without PnTx2-6 (10-8M). RESULTS The decrease in erectile function associated with age was partially restored 15-20 minutes after injection of PnTx2-6 and further improved by sildenafil. PnTx2-6 enhanced EFS-induced relaxation, as well as cGMP levels in CC, from young and aged rats. Relaxation due to PnTx2-6 was further increased after 30 minutes incubation with Y-27632, a Rho-kinase inhibitor (10-6 M), in aging CC. Nitric oxide synthase (NOS) activity in aged and young cavernosal tissue was increased by incubation with PnTx2-6 (10 minutes). However, this toxin did not modify NOS expression. CONCLUSION PnTx2-6 improves penile relaxation in aged rats, via increased NOS activity and NO release, resulting in enhanced cGMP levels.
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Affiliation(s)
- Kenia P Nunes
- Department of Physiology, Georgia Health Sciences University, Augusta, GA, USA.
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Nunes KP, Toque HA, Caldwell RB, William Caldwell R, Clinton Webb R. Extracellular Signal‐Regulated Kinase (ERK) Inhibition Decreases Arginase Activity and Improves Corpora Cavernosal Relaxation in Streptozotocin (STZ)‐Induced Diabetic Mice. J Sex Med 2011; 8:3335-44. [DOI: 10.1111/j.1743-6109.2011.02499.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Ma W, Han W, Greer PA, Tuder RM, Toque HA, Wang KKW, Caldwell RW, Su Y. Calpain mediates pulmonary vascular remodeling in rodent models of pulmonary hypertension, and its inhibition attenuates pathologic features of disease. J Clin Invest 2011; 121:4548-66. [PMID: 22005303 DOI: 10.1172/jci57734] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 08/25/2011] [Indexed: 11/17/2022] Open
Abstract
Pulmonary hypertension is a severe and progressive disease, a key feature of which is pulmonary vascular remodeling. Several growth factors, including EGF, PDGF, and TGF-β1, are involved in pulmonary vascular remodeling during pulmonary hypertension. However, increased knowledge of the downstream signaling cascades is needed if effective clinical interventions are to be developed. In this context, calpain provides an interesting candidate therapeutic target, since it is activated by EGF and PDGF and has been reported to activate TGF-β1. Thus, in this study, we examined the role of calpain in pulmonary vascular remodeling in two rodent models of pulmonary hypertension. These data showed that attenuated calpain activity in calpain-knockout mice or rats treated with a calpain inhibitor resulted in prevention of increased right ventricular systolic pressure, right ventricular hypertrophy, as well as collagen deposition and thickening of pulmonary arterioles in models of hypoxia- and monocrotaline-induced pulmonary hypertension. Additionally, inhibition of calpain in vitro blocked intracellular activation of TGF-β1, which led to attenuated Smad2/3 phosphorylation and collagen synthesis. Finally, smooth muscle cells of pulmonary arterioles from patients with pulmonary arterial hypertension showed higher levels of calpain activation and intracellular active TGF-β. Our data provide evidence that calpain mediates EGF- and PDGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells via an intracrine TGF-β1 pathway in pulmonary hypertension.
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Affiliation(s)
- Wanli Ma
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Health Sciences University, Augusta, Georgia, USA
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Abstract
Endothelial dysfunction is a key event in the development of vascular disease, and it precedes clinically obvious vascular pathology. Abnormal activation of the RhoA/Rho kinase (ROCK) pathway has been found to elevate vascular tone through unbalancing the production of vasodilating and vasoconstricting substances. Inhibition of the RhoA/ROCK pathway can prevent endothelial dysfunction in a variety of pathological conditions. This review, based on recent molecular, cellular, and animal studies, focuses on the current understanding of the ROCK pathway and its roles in endothelial dysfunction.
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Affiliation(s)
- Lin Yao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta, GA, USA
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37
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Nunes KP, Toque HA, Borges MN, De Lima ME, Webb RC. PnTx2‐6 Toxin, From Phoneutria nigriventer Spider Venom, Attenuates The Erectile Dysfunction In Aged Rats. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1049.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | - Maria Elena De Lima
- Biochemistry and ImmunologyFederal University of Minas GeraisBelo HorizonteBrazil
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Toque HA, Tostes RC, Yao L, Xu Z, Webb RC, Caldwell RB, Caldwell RW. Arginase II deletion increases corpora cavernosa relaxation in diabetic mice. J Sex Med 2010; 8:722-33. [PMID: 21054801 DOI: 10.1111/j.1743-6109.2010.02098.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Diabetes-induced erectile dysfunction involves elevated arginase (Arg) activity and expression. Because nitric oxide (NO) synthase and Arg share and compete for their substrate L-arginine, NO production is likely linked to regulation of Arg. Arg is highly expressed and implicated in erectile dysfunction. AIM It was hypothesized that Arg-II isoform deletion enhances relaxation function of corpora cavernosal (CC) smooth muscle in a streptozotocin (STZ) diabetic model. METHODS Eight weeks after STZ-induced diabetes, vascular functional studies, Arg activity assay, and protein expression levels of Arg and constitutive NOS (using Western blots) were assessed in CC tissues from nondiabetic wild type (WT), diabetic (D) WT (WT + D), Arg-II knockout (KO), and Arg-II KO+D mice (N = 8-10 per group). MAIN OUTCOME MEASURES Inhibition or lack of arginase results in facilitation of CC relaxation in diabetic CC. RESULTS Strips of CC from Arg-II KO mice exhibited an enhanced maximum endothelium-dependent relaxation (from 70 + 3% to 84 + 4%) and increased nitrergic relaxation (by 55%, 71%, 42%, 42%, and 24% for 1, 2, 4, 8 and 16 Hz, respectively) compared with WT mice. WT + D mice showed a significant reduction of endothelium-dependent maximum relaxation (44 + 8%), but this impairment of relaxation was significantly prevented in Arg-II KO+D mice (69 + 4%). Sympathetic-mediated and alpha-adrenergic agent-induced contractile responses also were increased in CC strips from D compared with non-D controls. Contractile responses were significantly lower in Arg-II KO control and D versus the WT groups. WT + D mice increased Arg activity (1.5-fold) and Arg-II protein expression and decreased total and phospho-eNOS at Ser-1177, and nNOS levels. These alterations were not seen in Arg-II KO mice. Additionally, the Arg inhibitor BEC (50 µM) enhanced nitrergic and endothelium-dependent relaxation in CC of WT + D mice. CONCLUSION These studies show for the first time that Arg-II deletion improves CC relaxation in type 1 diabetes.
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Affiliation(s)
- Haroldo A Toque
- Medical College of Georgia, Department of Pharmacology and Toxicology, Augusta, GA 30912-2300, USA.
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Toque HA, da Silva FH, Calixto MC, Lintomen L, Schenka AA, Saad MJ, Zanesco A, Antunes E. High-fat diet associated with obesity induces impairment of mouse corpus cavernosum responses. BJU Int 2010; 107:1628-34. [DOI: 10.1111/j.1464-410x.2010.09704.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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40
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Toque HA, Romero MJ, Tostes RC, Shatanawi A, Chandra S, Carneiro ZN, Inscho EW, Webb RC, Caldwell RB, Caldwell RW. p38 Mitogen-activated protein kinase (MAPK) increases arginase activity and contributes to endothelial dysfunction in corpora cavernosa from angiotensin-II-treated mice. J Sex Med 2010; 7:3857-67. [PMID: 20807329 DOI: 10.1111/j.1743-6109.2010.01996.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Angiotensin II (AngII) activates p38 mitogen-activated protein kinase (MAPK) and elevates arginase activity in endothelial cells. Upregulation of arginase activity has been implicated in endothelial dysfunction by reducing nitric oxide (NO) bioavailability. However, signaling pathways activated by AngII in the penis are largely unknown. AIM We hypothesized that activation of p38 MAPK increases arginase activity and thus impairs penile vascular function in AngII-treated mice. METHODS Male C57BL/6 mice were implanted with osmotic minipumps containing saline or AngII (42 µg/kg/h) for 14 days and cotreated with p38 MAPK inhibitor, SB 203580 (5 µg/kg/day), beginning 2 days before minipump implantation. Systolic blood pressure (SBP) was measured. Corpus cavernosum (CC) tissue was used for vascular functional studies and protein expression levels of p38 MAPK, arginase and constitutive NO synthase (NOS), and arginase activity. MAIN OUTCOME MEASURES Arginase expression and activity; expression of phospho-p38 MAPK, endothelial NOS (eNOS) and neuronal NOS proteins; endothelium-dependent and nitrergic nerve-mediated relaxations were determined in CC from control and AngII-infused mice. RESULTS AngII increased SBP (22%) and increased CC arginase activity and expression (∼twofold), and phosphorylated P38 MAPK levels (30%) over control. Treatment with SB 203580 prevented these effects. Endothelium-dependent NO-mediated relaxation to acetylcholine was significantly reduced by AngII and this effect was prevented by SB 203580 (P < 0.01). AngII (2 weeks) did not alter nitrergic function. However, SB 203580 significantly increased nitrergic relaxation in both control and AngII tissue at lower frequencies. Maximum contractile responses for phenylephrine and electrical field stimulation were increased by AngII (56% and 171%, respectively) and attenuated by SB 203580 treatment. AngII treatment also decreased eNOS phosphorylation at Ser-1177 compared to control. Treatment with SB 203580 prevented all these changes. CONCLUSION p38 MAPK inhibition corrects penile arginase activity and protects against erectile dysfunction caused by AngII.
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Affiliation(s)
- Haroldo A Toque
- Department of Pharmacology & Toxicology, Medical College of Georgia, Augusta, GA 30912, USA.
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Toque HA, Priviero FBM, Zemse SM, Antunes E, Teixeira CE, Webb RC. Effect of the phosphodiesterase 5 inhibitors sildenafil, tadalafil and vardenafil on rat anococcygeus muscle: functional and biochemical aspects. Clin Exp Pharmacol Physiol 2008; 36:358-66. [PMID: 18986324 DOI: 10.1111/j.1440-1681.2008.05071.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The anococcygeus muscle is part of the erectile machinery in male rodents. Phosphodiesterase (PDE) 5 inhibitors enhance and prolong the effects of cGMP, which has a key role in penile erection. The aim of the present study was to provide a functional and biochemical comparison of the three PDE5 inhibitors, namely sildenafil, tadalafil and vardenafil, in the rat anococcygeus muscle. 2. Muscle strips were mounted in 4 mL organ baths and isometric force recorded. Levels of cGMP were measured using an enzyme immunoassay kit. Western blots were used to determine PDE5 protein expression. 3. The PDE5 inhibitors concentration-dependently relaxed carbachol-precontracted anococcygeus muscle; however, vardenafil was more potent (pEC(50) = 8.11 +/- 0.05) than sildenafil (7.72 +/- 0.06) or tadalafil (7.69 +/- 0.05). Addition of N(G)-nitro-l-arginine methyl ester (100 micromol/L) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 micromol/L) to the organ baths caused significant rightward shifts in concentration-response curves for all PDE5 inhibitors. 4. Sildenafil, tadalafil and vardenafil (all at 0.1 micromol/L) caused leftward shifts in the glyceryl trinitrate (GTN) concentration-response curves (by 4.0-, 3.7- and 5.5-fold, respectively). In addition, all three PDE5 inhibitors significantly potentiated relaxation responses to both GTN (0.01-10 micromol/L) and electrical field stimulation (EFS; 1-32 Hz), with vardenafil having more pronounced effects. 5. All three PDE5 inhibitors reduced EFS-evoked contractions in a concentration-dependent manner over the concentration range 0.001-1 micromol/L. There were no significant differences between the effects of the three PDE5 inhibitors. 6. Vardenafil (0.01-0.1 micromol/L) was more potent in preventing cGMP degradation in vitro than sildenafil (0.01-0.1 micromol/L) and tadalafil (0.01-0.1 micromol/L). 7. Under control conditions, the expression of PDE5 was higher in the anococcygeus muscle than in the corpus cavernosum. 8. In conclusion, PDE5 inhibitors enhance exogenous and endogenous nitric oxide-mediated relaxation in the rat anococcygeus muscle. The potency of vardenafil was greater than that of either sildenafil or tadalafil.
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Affiliation(s)
- Haroldo A Toque
- Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, Campinas, São Paulo, Brazil.
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