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Bai YP, Hu CP, Yuan Q, Peng J, Shi RZ, Yang TL, Cao ZH, Li YJ, Cheng G, Zhang GG. Role of VPO1, a newly identified heme-containing peroxidase, in ox-LDL induced endothelial cell apoptosis. Free Radic Biol Med 2011; 51:1492-500. [PMID: 21820048 PMCID: PMC3570029 DOI: 10.1016/j.freeradbiomed.2011.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [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: 08/04/2010] [Revised: 07/07/2011] [Accepted: 07/11/2011] [Indexed: 12/19/2022]
Abstract
Myeloperoxidase (MPO) is an important enzyme involved in the genesis and development of atherosclerosis. Vascular peroxidase 1 (VPO1) is a newly discovered member of the peroxidase family that is mainly expressed in vascular endothelial cells and smooth muscle cells and has structural characteristics and biological activity similar to those of MPO. Our specific aims were to explore the effects of VPO1 on endothelial cell apoptosis induced by oxidized low-density lipoprotein (ox-LDL) and the underlying mechanisms. The results showed that ox-LDL induced endothelial cell apoptosis and the expression of VPO1 in endothelial cells in a concentration- and time-dependent manner concomitant with increased intracellular reactive oxygen species (ROS) and hypochlorous acid (HOCl) generation, and up-regulated protein expression of the NADPH oxidase gp91(phox) subunit and phosphorylation of p38 MAPK. All these effects of ox-LDL were inhibited by VPO1 gene silencing and NADPH oxidase gp91(phox) subunit gene silencing or by pretreatment with the NADPH oxidase inhibitor apocynin or diphenyliodonium. The p38 MAPK inhibitor SB203580 or the caspase-3 inhibitor DEVD-CHO significantly inhibited ox-LDL-induced endothelial cell apoptosis, but had no effect on intracellular ROS and HOCl generation or the expression of NADPH oxidase gp91(phox) subunit or VPO1. Collectively, these findings suggest for the first time that VPO1 plays a critical role in ox-LDL-induced endothelial cell apoptosis and that there is a positive feedback loop between VPO1/HOCl and the now-accepted dogma that the NADPH oxidase/ROS/p38 MAPK/caspase-3 pathway is involved in ox-LDL-induced endothelial cell apoptosis.
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Affiliation(s)
- Yong-Ping Bai
- Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China
- Department of Geriatric Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Chang-Ping Hu
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
| | - Qiong Yuan
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
| | - Jun Peng
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
| | - Rui-Zheng Shi
- Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Tian-Lun Yang
- Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Ze-Hong Cao
- Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yuan-Jian Li
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha 410078, China
| | - Guangjie Cheng
- Division of Pulmonary, Allergy & Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Corresponding authors. Fax: +1 086 731 84327695; +1 205 935 8565. (G. Cheng), (G.-G. Zhang)
| | - Guo-Gang Zhang
- Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China
- Corresponding authors. Fax: +1 086 731 84327695; +1 205 935 8565. (G. Cheng), (G.-G. Zhang)
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Cheng G, Li H, Cao Z, Qiu X, McCormick S, Thannickal VJ, Nauseef WM. Vascular peroxidase-1 is rapidly secreted, circulates in plasma, and supports dityrosine cross-linking reactions. Free Radic Biol Med 2011; 51:1445-53. [PMID: 21798344 PMCID: PMC3439998 DOI: 10.1016/j.freeradbiomed.2011.07.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [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: 02/21/2011] [Revised: 06/10/2011] [Accepted: 07/04/2011] [Indexed: 02/07/2023]
Abstract
Members of the peroxidase-cyclooxygenase superfamily catalyze biochemical reactions essential to a broad spectrum of biological processes, including host defense, thyroid hormone biosynthesis, and modification of extracellular matrix, as well as contributing to the pathogenesis of chronic inflammatory diseases. We recently identified a novel member of this family, vascular peroxidase-1 (VPO1), that is highly expressed in the human cardiovascular system. Its biosynthesis and enzymatic properties are largely unknown. Here, we report that VPO1 was rapidly and efficiently secreted into the extracellular space when the gene was stably expressed in human embryonic kidney (HEK) cells. Secreted VPO1 is a monomer with complex N-linked oligosaccharides and exhibits peroxidase activity. Biosynthesis of endogenous VPO1 by cultured human umbilical vein endothelial cells (HUVECs) shares features exhibited by heterologous expression of recombinant VPO1 (rVPO1) in HEK cells. The proinflammatory agents lipopolysaccharide and tumor necrosis factor-α induce expression of VPO1 mRNA and protein in HUVECs. Furthermore, murine and bovine sera and human plasma contain enzymatically active VPO1. rVPO1 exhibits spectral and enzymatic properties characteristic of the peroxidase-cyclooxygenase family, except with regard to its heat stability. rVPO1 catalyzes tyrosyl radical formation and promotes dityrosine cross-linking. Taken together, these data demonstrate that VPO1 is a glycosylated heme peroxidase that is actively secreted into circulating plasma by vascular endothelial cells and shares several features with other members of the peroxidase-cyclooxygenase family, including the catalysis of dityrosine formation.
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Affiliation(s)
- Guangjie Cheng
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, AL, USA
- Correspondence: Guangjie Cheng, Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, BMR2, Room 410, 1530 3rd Avenue South, Birmingham, AL, 35294 USA; Phone 205-975-8919; Fax 205-975-3043, ; or William M. Nauseef, Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa and Veterans Affairs Medical Center, Coralville, Iowa City, IA, USA; Phone 319-335-4278; Fax 319-335-4194;
| | - Hong Li
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, AL, USA
| | - Zehong Cao
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, AL, USA
| | - Xiaoyun Qiu
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, AL, USA
| | - Sally McCormick
- Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa and Veterans Affairs Medical Center, Coralville, Iowa City, IA, USA
| | - Victor J. Thannickal
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, Birmingham, AL, USA
| | - William M. Nauseef
- Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa and Veterans Affairs Medical Center, Coralville, Iowa City, IA, USA
- Correspondence: Guangjie Cheng, Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama School of Medicine, BMR2, Room 410, 1530 3rd Avenue South, Birmingham, AL, 35294 USA; Phone 205-975-8919; Fax 205-975-3043, ; or William M. Nauseef, Inflammation Program, Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa and Veterans Affairs Medical Center, Coralville, Iowa City, IA, USA; Phone 319-335-4278; Fax 319-335-4194;
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