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Chen X, Wang H, Wu C, Li X, Huang X, Ren Y, Pu Q, Cao Z, Tang X, Ding BS. Endothelial H 2S-AMPK dysfunction upregulates the angiocrine factor PAI-1 and contributes to lung fibrosis. Redox Biol 2024; 70:103038. [PMID: 38266576 PMCID: PMC10811458 DOI: 10.1016/j.redox.2024.103038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/28/2023] [Accepted: 01/10/2024] [Indexed: 01/26/2024] Open
Abstract
Dysfunction of the vascular angiocrine system is critically involved in regenerative defects and fibrosis of injured organs. Previous studies have identified various angiocrine factors and found that risk factors such as aging and metabolic disorders can disturb the vascular angiocrine system in fibrotic organs. One existing key gap is what sense the fibrotic risk to modulate the vascular angiocrine system in organ fibrosis. Here, using human and mouse data, we discovered that the metabolic pathway hydrogen sulfide (H2S)-AMP-activated protein kinase (AMPK) is a sensor of fibrotic stress and serves as a key mechanism upregulating the angiocrine factor plasminogen activator inhibitor-1 (PAI-1) in endothelial cells to participate in lung fibrosis. Activation of the metabolic sensor AMPK was inhibited in endothelial cells of fibrotic lungs, and AMPK inactivation was correlated with enriched fibrotic signature and reduced lung functions in humans. The inactivation of endothelial AMPK accelerated lung fibrosis in mice, while the activation of endothelial AMPK with metformin alleviated lung fibrosis. In fibrotic lungs, endothelial AMPK inactivation led to YAP activation and overexpression of the angiocrine factor PAI-1, which was positively correlated with the fibrotic signature in human fibrotic lungs and inhibition of PAI-1 with Tiplaxtinin mitigated lung fibrosis. Further study identified that the deficiency of the antioxidative gas metabolite H2S accounted for the inactivation of AMPK and activation of YAP-PAI-1 signaling in endothelial cells of fibrotic lungs. H2S deficiency was involved in human lung fibrosis and H2S supplement reversed mouse lung fibrosis in an endothelial AMPK-dependent manner. These findings provide new insight into the mechanism underlying the deregulation of the vascular angiocrine system in fibrotic organs.
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Affiliation(s)
- Xiangqi Chen
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Han Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Chuan Wu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaoyan Li
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaojuan Huang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Yafeng Ren
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Qiang Pu
- Department of Thoracic Surgery, National Frontier Center of Disease Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zhongwei Cao
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xiaoqiang Tang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Bi-Sen Ding
- Key Laboratory of Birth Defects and Related Diseases of Women and Children of MOE, State Key Laboratory of Biotherapy, NHC Key Laboratory of Chronobiology, Development and Related Diseases of Women and Children, Key Laboratory of Sichuan Province, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
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Wu M, Wang S, Hai W, Lu X, Li P. Development of a H 2S-responsive NIR Fluorescent Probe for H 2S Detection and H 2S Releasing Monitoring From Prodrug. J Fluoresc 2023; 33:1853-1860. [PMID: 36867290 DOI: 10.1007/s10895-023-03187-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 02/16/2023] [Indexed: 03/04/2023]
Abstract
H2S was deemed as a toxic gradient in the realm of food and environment but plays pivotal pathophysiological roles in organisms. H2S instabilities and disturbances are always responsible for multiple disorders. We fabricated a H2S-responsive NIR fluorescent probe (HT) for H2S detection and evaluation both in vitro and in vivo. HT exhibited rapid H2S response within 5 min, accompanied with visible color change and NIR fluorescence generation, and the fluorescent intensities were linearly correlated with corresponding H2S concentrations. When HT was incubated with A549 cells, the intracellular H2S and H2S fluctuations could be monitored ore rotundo via the responsive fluorescence. Meanwhile, when HT was co-administrated with H2S prodrug ADT-OH, the H2S release from ADT-OH could be visualized and monitored to evaluate its release efficacy.
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Affiliation(s)
- Muyu Wu
- Department of Nuclear Medicine, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Siwen Wang
- Department of Nuclear Medicine, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Wangxi Hai
- Department of Nuclear Medicine, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Xinmiao Lu
- Department of Nuclear Medicine, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, 200025, China.
| | - Peiyong Li
- Department of Nuclear Medicine, School of Medicine, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, 200025, China.
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3
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Combi Z, Potor L, Nagy P, Sikura KÉ, Ditrói T, Jurányi EP, Galambos K, Szerafin T, Gergely P, Whiteman M, Torregrossa R, Ding Y, Beke L, Hendrik Z, Méhes G, Balla G, Balla J. Hydrogen sulfide as an anti-calcification stratagem in human aortic valve: Altered biogenesis and mitochondrial metabolism of H 2S lead to H 2S deficiency in calcific aortic valve disease. Redox Biol 2023; 60:102629. [PMID: 36780769 PMCID: PMC9947110 DOI: 10.1016/j.redox.2023.102629] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Hydrogen sulfide (H2S) was previously revealed to inhibit osteoblastic differentiation of valvular interstitial cells (VICs), a pathological feature in calcific aortic valve disease (CAVD). This study aimed to explore the metabolic control of H2S levels in human aortic valves. Lower levels of bioavailable H2S and higher levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected in aortic valves of CAVD patients compared to healthy individuals, accompanied by higher expression of cystathionine γ-lyase (CSE) and same expression of cystathionine β-synthase (CBS). Increased biogenesis of H2S by CSE was found in the aortic valves of CAVD patients which is supported by increased production of lanthionine. In accordance, healthy human aortic VICs mimic human pathology under calcifying conditions, as elevated CSE expression is associated with low levels of H2S. The expression of mitochondrial enzymes involved in H2S catabolism including sulfide quinone oxidoreductase (SQR), the key enzyme in mitochondrial H2S oxidation, persulfide dioxygenase (ETHE1), sulfite oxidase (SO) and thiosulfate sulfurtransferase (TST) were up-regulated in calcific aortic valve tissues, and a similar expression pattern was observed in response to high phosphate levels in VICs. AP39, a mitochondria-targeting H2S donor, rescued VICs from an osteoblastic phenotype switch and reduced the expression of IL-1β and TNF-α in VICs. Both pro-inflammatory cytokines aggravated calcification and osteoblastic differentiation of VICs derived from the calcific aortic valves. In contrast, IL-1β and TNF-α provided an early and transient inhibition of VICs calcification and osteoblastic differentiation in healthy cells and that effect was lost as H2S levels decreased. The benefit was mediated via CSE induction and H2S generation. We conclude that decreased levels of bioavailable H2S in human calcific aortic valves result from an increased H2S metabolism that facilitates the development of CAVD. CSE/H2S represent a pathway that reverses the action of calcifying stimuli.
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Affiliation(s)
- Zsolt Combi
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, University of Debrecen, 11003, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - László Potor
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, University of Debrecen, 11003, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Péter Nagy
- Department of Molecular Immunology and Toxicology and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary; Institute of Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary; Department of Anatomy and Histology, ELKH Laboratory of Redox Biology, University of Veterinary Medicine, Budapest, Hungary
| | - Katalin Éva Sikura
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, University of Debrecen, 11003, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Tamás Ditrói
- Department of Molecular Immunology and Toxicology and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary
| | - Eszter Petra Jurányi
- Department of Molecular Immunology and Toxicology and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary; Doctoral School of Molecular Medicine, Semmelweis University, Budapest, Hungary
| | - Klaudia Galambos
- Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary; Department of Molecular Immunology and Toxicology and the National Tumor Biology Laboratory, National Institute of Oncology, Budapest, Hungary
| | - Tamás Szerafin
- Department of Cardiac Surgery, Faculty of Medicine, University of Debrecen, Hungary
| | - Péter Gergely
- Institute of Forensic Medicine, Faculty of Medicine, University of Debrecen, Hungary
| | - Matthew Whiteman
- University of Exeter Medical School, St. Luke's Campus, Magdalen Road, Exeter, EX1 2LU, UK
| | - Roberta Torregrossa
- University of Exeter Medical School, St. Luke's Campus, Magdalen Road, Exeter, EX1 2LU, UK
| | - Yuchao Ding
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Lívia Beke
- Institute of Pathology, Faculty of Medicine, University of Debrecen, Hungary
| | - Zoltán Hendrik
- Institute of Forensic Medicine, Faculty of Medicine, University of Debrecen, Hungary
| | - Gábor Méhes
- Institute of Pathology, Faculty of Medicine, University of Debrecen, Hungary
| | - György Balla
- ELKH-UD Vascular Pathophysiology Research Group, University of Debrecen, 11003, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary; Department of Pediatrics, Faculty of Medicine, University of Debrecen, Hungary
| | - József Balla
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, University of Debrecen, 11003, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary.
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Zhang Y, Jing M, Cai C, Zhu S, Zhang C, Wang Q, Zhai Y, Ji X, Wu D. Role of hydrogen sulphide in physiological and pathological angiogenesis. Cell Prolif 2022; 56:e13374. [PMID: 36478328 PMCID: PMC9977675 DOI: 10.1111/cpr.13374] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/08/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
The role of hydrogen sulphide (H2 S) in angiogenesis has been widely demonstrated. Vascular endothelial growth factor (VEGF) plays an important role in H2 S-induced angiogenesis. H2 S promotes angiogenesis by upregulating VEGF via pro-angiogenic signal transduction. The involved signalling pathways include the mitogen-activated protein kinase pathway, phosphoinositide-3 kinase pathway, nitric oxide (NO) synthase/NO pathway, signal transducer and activator of transcription 3 (STAT3) pathway, and adenosine triphosphate (ATP)-sensitive potassium (KATP ) channels. H2 S has been shown to contribute to tumour angiogenesis, diabetic wound healing, angiogenesis in cardiac and cerebral ischaemic tissues, and physiological angiogenesis during the menstrual cycle and pregnancy. Furthermore, H2 S can exert an anti-angiogenic effect by inactivating Wnt/β-catenin signalling or blocking the STAT3 pathway in tumours. Therefore, H2 S plays a double-edged sword role in the process of angiogenesis. The regulation of H2 S production is a promising therapeutic approach for angiogenesis-associated diseases. Novel H2 S donors and/or inhibitors can be developed in the treatment of angiogenesis-dependent diseases.
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Affiliation(s)
- Yan‐Xia Zhang
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Mi‐Rong Jing
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Chun‐Bo Cai
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Shuai‐Gang Zhu
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Chao‐Jing Zhang
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Qi‐Meng Wang
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina
| | - Yuan‐Kun Zhai
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,School of StomatologyHenan UniversityKaifengHenanChina
| | - Xin‐Ying Ji
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina,Kaifeng Key Laboratory of Infection and Biological Safety, School of Basic Medical SciencesHenan UniversityKaifengHenanChina
| | - Dong‐Dong Wu
- Henan International Joint Laboratory for Nuclear Protein Regulation, School of Basic Medical SciencesHenan UniversityKaifengHenanChina,Kaifeng Municipal Key Laboratory of Cell Signal Transduction, Henan Provincial Engineering Centre for Tumor Molecular MedicineHenan UniversityKaifengHenanChina,School of StomatologyHenan UniversityKaifengHenanChina
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5
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Gáll T, Nagy P, Garai D, Potor L, Balla GJ, Balla G, Balla J. Overview on hydrogen sulfide-mediated suppression of vascular calcification and hemoglobin/heme-mediated vascular damage in atherosclerosis. Redox Biol 2022; 57:102504. [PMID: 36240620 PMCID: PMC9576974 DOI: 10.1016/j.redox.2022.102504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 12/04/2022] Open
Abstract
Vulnerable atherosclerotic plaques with hemorrhage considerably contribute to cardiovascular morbidity and mortality. Calcification is the main characteristic of advanced atherosclerotic lesions and calcified aortic valve disease (CAVD). Lyses of red blood cells and hemoglobin (Hb) release occur in human hemorrhagic complicated lesions. During the interaction of cell-free Hb with plaque constituents, Hb is oxidized to ferric and ferryl states accompanied by oxidative changes of the globin moieties and heme release. Accumulation of both ferryl-Hb and metHb has been observed in atherosclerotic plaques. The oxidation hotspots in the globin chain are the cysteine and tyrosine amino acids associated with the generation of Hb dimers, tetramers and polymers. Moreover, fragmentation of Hb occurs leading to the formation of globin-derived peptides. A series of these pro-atherogenic cellular responses can be suppressed by hydrogen sulfide (H2S). Since H2S has been explored to exhibit a wide range of physiologic functions to maintain vascular homeostasis, it is not surprising that H2S may play beneficial effects in the progression of atherosclerosis. In the present review, we summarize the findings about the effects of H2S on atherosclerosis and CAVD with a special emphasis on the oxidation of Hb/heme in atherosclerotic plaque development and vascular calcification.
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Affiliation(s)
- Tamás Gáll
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, 11003, University of Debrecen, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - Péter Nagy
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Budapest, Hungary; Institute of Oncochemistry, University of Debrecen, Hungary
| | - Dorottya Garai
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Budapest, Hungary
| | - László Potor
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, 11003, University of Debrecen, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | | | - György Balla
- Department of Pediatrics, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, 11003, University of Debrecen, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary
| | - József Balla
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Hungary; ELKH-UD Vascular Pathophysiology Research Group, 11003, University of Debrecen, Hungary; Kálmán Laki Doctoral School, University of Debrecen, Debrecen, Hungary.
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Li J, Li M, Li L, Ma J, Yao C, Yao S. Hydrogen sulfide attenuates ferroptosis and stimulates autophagy by blocking mTOR signaling in sepsis-induced acute lung injury. Mol Immunol 2022; 141:318-327. [PMID: 34952420 DOI: 10.1016/j.molimm.2021.12.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 10/21/2021] [Accepted: 12/01/2021] [Indexed: 12/14/2022]
Abstract
Sepsis often leads to multiple organ failure or even death and is a significant health problem that contributes to a heavy economic burden. The lung is the first organ to be affected by sepsis. Presently, there is no specific drug or method to treat sepsis and sepsis-induced acute lung injury (ALI). H2S, along with CO and NO, is a physiological gas that acts as a signaling molecule and plays an active role in fighting various lung infections. GYY4137 is a novel H2S donor that is stable in vivo and in vitro. However, particularly in the context of ferroptosis, GYY4137 affects cecal ligation and puncture (CLP)-induced ALI by a mechanism that is not understood. Ferroptosis is a new form of cell necrosis. The primary mechanism is the accumulation of cellular lipid ROS in an iron-dependent manner. The principal objective of this project was to investigate the effects of GYY4137 on ferroptosis and autophagy in a mouse model of sepsis-induced ALI. We divided the experimental mice randomly into 5 groups: (1) sham group; (2) CLP group; (3) CLP + DMSO group: (4) CLP + GYY4137 (25 mg/kg) group; and (5) CLP + GYY4137 (50 mg/kg) group. (6) CLP + Rapamycin (2.0 mg/Kg) group. (7) CLP + Chloroquine (80 mg/Kg) group. (8) the Chloroquine (80 mg/Kg) + GYY (50 mg/Kg) group. The findings showed that GYY4137 significantly protected against CLP-induced ALI by improving sepsis-induced lung histopathological changes, diminishing lung tissue damage, ameliorating oxidative stress, and attenuating the severity of lung injury in mice. In this study, we found that GYY4137 could alleviate septicemia-induced ferroptosis in ALI by increasing the expression of GPx4 and SLC7A11 in lung tissue after CLP. One unexpected finding was the extent to which the levels of ferritin and ferritin light chain increased after CLP, which may be a compensatory mechanism for storing abnormally increased iron. We also found that the expression of p-mTOR, P62, and Beclin1 was significantly increased and that LC3II/LC3I declined after LPS stimulation, but the effect was inhibited by treatment with GYY4137, indicating that GYY4137 could inhibit the activation of autophagy in sepsis-induced ALI by blocking mTOR signaling.
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Affiliation(s)
- Jianhua Li
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Department of Critical Care Medicine, The First Affiliated Hospital, College of Medicine, Shihezi University, Shihezi 832000, China
| | - Mengyu Li
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ling Li
- Department of Traumatology, The First Affiliated Hospital, College of Medicine, Shihezi University, Shihezi 832000, China
| | - Jiamin Ma
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chengye Yao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Shanglong Yao
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Anesthesia and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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GYY4137 alleviates sepsis-induced acute lung injury in mice by inhibiting the PDGFRβ/Akt/NF-κB/NLRP3 pathway. Life Sci 2021; 271:119192. [PMID: 33577850 DOI: 10.1016/j.lfs.2021.119192] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/15/2021] [Accepted: 01/31/2021] [Indexed: 12/29/2022]
Abstract
AIMS GYY4137 [GYY, morpholin-4-ium-4-methoxyphenyl (morpholino) phosphinodithioate] is a novel and perfect hydrogen sulfide (H2S) donor that is stable in vivo and in vitro. H2S, along with CO and NO, has been recognized as the third physiological gas signaling molecule that plays an active role in fighting various lung infections. However, the mechanism by which GYY4137 affects cecal ligation and puncture (CLP)-induced acute lung injury (ALI) is not understood. This study aimed to investigate whether GYY4137 inhibits the activation of the pyrin domain-containing protein 3 (NLRP3) inflammasome by inhibiting the PDGFRβ/Akt/NF-κB pathway. MAIN METHODS The model of CLP-induced ALI was established in vivo. The mice were subsequently treated with GYY4137 (25 μg/g and 50 μg/g) to simulate the realistic conditions of pathogenesis. Western blotting and immunohistochemical staining were used to examine protein expression, hematoxylin and eosin staining was used for the histopathological analysis, and the levels of inflammatory factors were determined using enzyme-linked immunosorbent assays (ELISAs). KEY FINDINGS GYY4137 significantly increased the 7-day survival of mice with septic peritonitis and protected against CLP-induced ALI, including decreasing neutrophil infiltration, improving sepsis-induced lung histopathological changes, diminishing lung tissue damage, and attenuating the severity of lung injury in mice. The protective effect of GYY4137 was undoubtedly dose-dependent. We discovered that GYY4137 reduced the levels of the p-PDGFRβ, p-NF-κB, ASC, NLRP3, caspase-1, and p-Akt proteins in septic mouse lung tissue. Akt regulates the generation of proinflammatory cytokines in endotoxemia-associated ALI by enhancing the nuclear translocation of NF-κB. SIGNIFICANCE These results indicate a new molecular mechanism explaining the effect of GYY4137 on the treatment of CLP-induced ALI in mice.
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Yao X, Liu W, Zhu W, Tiemuer A, Zhou F, Yang S, Yu H, Qian X, Liu Y. Near-infrared fluorescent chemodosimeter for real-time in vivo evaluation of H2S-release efficiency of prodrug. Chem Commun (Camb) 2020; 56:8111-8114. [DOI: 10.1039/d0cc02814b] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A promising platform for evaluating H2S-release in pharmaceutical development, and enabling a great method for monitoring H2S in future clinical medicine.
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Affiliation(s)
- Xufeng Yao
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Wangwang Liu
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Wenchao Zhu
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Aliya Tiemuer
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Fangyuan Zhou
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Shikui Yang
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Hui Yu
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Xiaoli Qian
- School of Engineering
- China Pharmaceutical University
- P. R. China
| | - Yi Liu
- School of Engineering
- China Pharmaceutical University
- P. R. China
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9
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Malik A, Jee B, Gupta SK. Preeclampsia: Disease biology and burden, its management strategies with reference to India. Pregnancy Hypertens 2018; 15:23-31. [PMID: 30825923 DOI: 10.1016/j.preghy.2018.10.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 11/19/2022]
Abstract
Preeclampsia is the cause of significant maternal and fetal mortality and morbidity. It is characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. Preeclamptic women and children born from preeclamptic pregnancies are at greater risk to develop severe cardiovascular complications and metabolic syndromes later in life. The incidence of preeclampsia is estimated to be seven times higher in developing countries as compared to the developed countries. This review summarizes the pathophysiology of preeclampsia, emerging new hypothesis of its origin, risk factors that make women susceptible to developing preeclampsia and the potential of various biomarkers being studied to predict preeclampsia. The health care of developing countries is continuously challenged by substantial burden of maternal and fetal mortality. India despite being a fast developing country, is still far behind in achieving the required maternal mortality rates as per Millennium Development Goals set by the World Health Organization. Further, this review discusses the prevalence of preeclampsia in India, health facilities to manage preeclampsia, current guidelines and protocols followed and government policies to combat this complication in Indian condition.
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Affiliation(s)
- Ankita Malik
- Reproductive Cell Biology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
| | - Babban Jee
- Department of Health Research, Ministry of Health and Family Welfare, Government of India, New Delhi 110 001, India
| | - Satish Kumar Gupta
- Reproductive Cell Biology Lab, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067, India.
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Implications of plasma thiol redox in disease. Clin Sci (Lond) 2018; 132:1257-1280. [DOI: 10.1042/cs20180157] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/09/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022]
Abstract
Thiol groups are crucially involved in signaling/homeostasis through oxidation, reduction, and disulphide exchange. The overall thiol pool is the resultant of several individual pools of small compounds (e.g. cysteine), peptides (e.g. glutathione), and thiol proteins (e.g. thioredoxin (Trx)), which are not in equilibrium and present specific oxidized/reduced ratios. This review addresses mechanisms and implications of circulating plasma thiol/disulphide redox pools, which are involved in several physiologic processes and explored as disease biomarkers. Thiol pools are regulated by mechanisms linked to their intrinsic reactivity against oxidants, concentration of antioxidants, thiol-disulphide exchange rates, and their dynamic release/removal from plasma. Major thiol couples determining plasma redox potential (Eh) are reduced cysteine (CyS)/cystine (the disulphide form of cysteine) (CySS), followed by GSH/disulphide-oxidized glutathione (GSSG). Hydrogen peroxide and hypohalous acids are the main plasma oxidants, while water-soluble and lipid-soluble small molecules are the main antioxidants. The thiol proteome and thiol-oxidoreductases are emerging investigative areas given their specific disease-related responses (e.g. protein disulphide isomerases (PDIs) in thrombosis). Plasma cysteine and glutathione redox couples exhibit pro-oxidant changes directly correlated with ageing/age-related diseases. We further discuss changes in thiol-disulphide redox state in specific groups of diseases: cardiovascular, cancer, and neurodegenerative. These results indicate association with the disease states, although not yet clear-cut to yield specific biomarkers. We also highlight mechanisms whereby thiol pools affect atherosclerosis pathophysiology. Overall, it is unlikely that a single measurement provides global assessment of plasma oxidative stress. Rather, assessment of individual thiol pools and thiol-proteins specific to any given condition has more solid and logical perspective to yield novel relevant information on disease risk and prognosis.
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Kumar MR, Farmer PJ. Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of H 2S. Redox Biol 2018; 14:485-491. [PMID: 29096321 PMCID: PMC5680521 DOI: 10.1016/j.redox.2017.10.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/08/2017] [Accepted: 10/15/2017] [Indexed: 12/29/2022] Open
Abstract
Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated during the oxidation of hydrogen sulfide, H2S, in aqueous solution. Unlike their alkyl homologs, there is a little data on their generation and speciation during H2S oxidation. These SOS may exhibit both nucleophilic and electrophilic reactivity, which we attribute to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivatization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC MS. In this report, we compare SOS formation from H2S oxidation by a variety of biologically relevant oxidants. These SOS appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects of H2S.
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Affiliation(s)
- Murugaeson R Kumar
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798, United States
| | - Patrick J Farmer
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798, United States.
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Tian D, Dong J, Jin S, Teng X, Wu Y. Endogenous hydrogen sulfide-mediated MAPK inhibition preserves endothelial function through TXNIP signaling. Free Radic Biol Med 2017; 110:291-299. [PMID: 28669627 DOI: 10.1016/j.freeradbiomed.2017.06.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 06/03/2017] [Accepted: 06/26/2017] [Indexed: 12/20/2022]
Abstract
Mounting evidence demonstrated deficient cystathionine-γ-lyase (CSE)/H2S implicated the development of cardiovascular disease. The present study aimed to evaluating the favorable action of CSE derived H2S on endothelial function in CSE-/- mice. CSE-/- mice exhibited attenuated endothelium-dependent relaxations, coupled with reduction of endothelial nitric oxide synthase (eNOS) phosphorylation at site of Ser1177, increase of thioredoxin interacting protein (TXNIP) level and MAPK phosphorylation, which were corrected by sodium hydrosulfide chronic treatment for 8 weeks. Impaired relaxations to ACh and upregulated TXNIP of CSE-/- mice aorta were partially corrected by p38 inhibitor, extracellular regulated protein kinase (ERK) inhibitor and c-Jun N-terminal kinase (JNK) inhibitor and totally corrected by combined treatment. Pharmacological inhibition of CSE with DL-propargylglycine (PPG) in vivo and ex vivo induced endothelial dysfunction. PPG stimulated the phosphorylation of p38, JNK and ERK in human umbilical vein endothelial cells (HUVECs). MAPK inhibition by combined treatment of p38, JNK and ERK inhibitors normalized the endothelial changes of eNOS phosphorylation and TXNIP protein level in CSE-/- mice aorta and PPG-treated HUVECs. NaHS offered similar effect with MAKP inhibitors. TXNIP siRNA prevented against endothelial function by PPG and TXNIP overexpression mimics the detrimental effect of PPG treatment on endothelial function, whereas MAPK inhibitor or NaHS has no beneficial effect. In a word, Endogenous CSE/H2S benefits against endothelial dysfunction through suppressing MAPK/TXNIP cascade. CSE deficiency and consequently lowered endogenous H2S level should be considered as risk factors and biomarkers for endothelial dysfunction.
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Affiliation(s)
- Danyang Tian
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Jinghui Dong
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Sheng Jin
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Xu Teng
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Yuming Wu
- Department of Physiology, Hebei Medical University, Shijiazhuang, China; Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang 050017, China.
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Ahmed A, Ramma W. Unravelling the theories of pre-eclampsia: are the protective pathways the new paradigm? Br J Pharmacol 2016; 172:1574-86. [PMID: 25303561 PMCID: PMC4354257 DOI: 10.1111/bph.12977] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 09/30/2014] [Accepted: 10/05/2014] [Indexed: 01/03/2023] Open
Abstract
Pre-eclampsia is a vascular disorder of pregnancy where anti-angiogenic factors, systemic inflammation and oxidative stress predominate, but none can claim to cause pre-eclampsia. This review provides an alternative to the ‘two-stage model’ of pre-eclampsia in which abnormal spiral arteries modification leads to placental hypoxia, oxidative stress and aberrant maternal systemic inflammation. Very high maternal soluble fms-like tyrosine kinase-1 (sFlt-1 also known as sVEGFR) and very low placenta growth factor (PlGF) are unique to pre-eclampsia; however, abnormal spiral arteries and excessive inflammation are also prevalent in other placental disorders. Metaphorically speaking, pregnancy can be viewed as a car with an accelerator and brakes, where inflammation, oxidative stress and an imbalance in the angiogenic milieu act as the ‘accelerator’. The ‘braking system’ includes the protective pathways of haem oxygenase 1 (also referred as Hmox1 or HO-1) and cystathionine-γ-lyase (also known as CSE or Cth), which generate carbon monoxide (CO) and hydrogen sulphide (H2S) respectively. The failure in these pathways (brakes) results in the pregnancy going out of control and the system crashing. Put simply, pre-eclampsia is an accelerator–brake defect disorder. CO and H2S hold great promise because of their unique ability to suppress the anti-angiogenic factors sFlt-1 and soluble endoglin as well as to promote PlGF and endothelial NOS activity. The key to finding a cure lies in the identification of cheap, safe and effective drugs that induce the braking system to keep the pregnancy vehicle on track past the finishing line.
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Affiliation(s)
- Asif Ahmed
- Vascular Therapeutics Unit, Aston Medical School, Aston University, Birmingham, UK
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Huang S, Li H, Ge J. A cardioprotective insight of the cystathionine γ-lyase/hydrogen sulfide pathway. IJC HEART & VASCULATURE 2015; 7:51-57. [PMID: 28785645 PMCID: PMC5497180 DOI: 10.1016/j.ijcha.2015.01.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 11/29/2014] [Accepted: 01/20/2015] [Indexed: 11/29/2022]
Abstract
Traditionally, hydrogen sulfide (H2S) was simply considered as a toxic and foul smelling gas, but recently H2S been brought into the spot light of cardiovascular research and development. Since the 1990s, H2S has been mounting evidence of physiological properties such as immune modification, vascular relaxation, attenuation of oxidative stress, inflammatory mitigation, and angiogenesis. H2S has since been recognized as the third physiological gaseous signaling molecule, along with CO and NO [65,66]. H2S is produced endogenously through several key enzymes, including cystathionine β-lyase (CBE), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MST)/cysteine aminotransferase (CAT). These specific enzymes are expressed accordingly in various organ systems and CSE is the predominant H2S-producing enzyme in the cardiovascular system. The cystathionine γ-lyase (CSE)/H2S pathway has demonstrated various cardioprotective effects, including anti-atherosclerosis, anti-hypertension, pro-angiogenesis, and attenuation of myocardial ischemia-reperfusion injury. CSE exhibits its anti-atherosclerotic effect through 3 mechanisms, namely reduction of chemotactic factor inter cellular adhesion molecule-1 (ICAM-1) and CX3CR1, inhibition of macrophage lipid uptake, and induction of smooth muscle cell apoptosis via MAPK pathway. The CSE/H2S pathway's anti-hypertensive properties are demonstrated via aortic vasodilation through several mechanisms, including the direct stimulation of KATP channels of vascular smooth muscle cells (VSMCs), induction of MAPK pathway, and reduction of homocysteine buildup. Also, CSE/H2S pathway plays an important role in angiogenesis, particularly in increased endothelial cell growth and migration, and in increased vascular network length. In myocardial ischemia-reperfusion injuries, CSE/H2S pathway has shown a clear cardioprotective effect by preserving mitochondria function, increasing antioxidant production, and decreasing infarction injury size. However, CSE/H2S pathway's role in inflammation mitigation is still clouded, due to both pro and anti-inflammatory results presented in the literature, depending on the concentration and form of H2S used in specific experiment models.
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Key Words
- Akt, protein kinase B
- Angiogenesis
- Atherosclerosis
- BCA, brachiocephalic artery
- CAM, chorioallantoic membrane
- CAT, cysteine aminotransferase
- CBS, cystathionine β-lyase
- CLP, cecal ligation and puncture
- CSE KO, CSE knock out
- CSE, cystathionine γ-lyase
- CTO, chronic total occlusion
- CX3CL1, chemokine (C-X3-C Motif) ligand 1
- CX3CR1, CX3C chemokine receptor 1
- Cystathionine γ-lyase
- EC, endothelial cell
- ERK, extracellular signal-regulated kinase
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- GSH-Px, glutathione peroxidase
- GYY4137, morpholin-4-Ium-4-methoxyphenyl(morpholino) phosphinodithioate
- H2S, hydrogen sulfide
- HUVECs, human umbilical vein endothelial cells
- Hydrogen sulfide
- ICAM-1, inter cellular adhesion molecule-1
- IMT, intima–media complex thickness
- Ischemia–reperfusion injury
- LPS, lipopolysaccharide
- MAPK, mitogen-activated protein kinase
- MPO, myeloperoxidase
- MST, 3-mercaptopyruvate sulfurtransferase
- NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells
- Nrf2, nuclear factor erythroid 2-related factor 2
- PAG, DL-propagylglycine
- PPAR-γ, peroxisome proliferator-activated receptor
- PTPN1, protein tyrosine phosphatase, non-receptor type 1
- ROS, reactive oxygen species
- S-diclofenac, 2-[(2,6-dichlorophenyl)amino]benzeneacetic acid 4-(3H-1,2-dithiole-3-thione-5-Yl)-phenyl ester
- SAH, S-adenosylhomocysteine
- SAM, S-adenosylmethionine
- SMCs, smooth muscle cells
- SOD, superoxide dismutase
- VEGF, vascular endothelial growth factor
- VSMCs, vascular smooth muscle cells
- Vasorelaxation
- l-NAME, NG-nitro-l-arginine methyl ester
- oxLDL, oxidized low density lipoprotein
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Affiliation(s)
- Steve Huang
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Hua Li
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Departments of Physiology and Medicine/CVRL, UCLA School of Medicine, Los Angeles, CA 90095, USA
| | - Junbo Ge
- Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
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Pálinkás Z, Furtmüller PG, Nagy A, Jakopitsch C, Pirker KF, Magierowski M, Jasnos K, Wallace JL, Obinger C, Nagy P. Interactions of hydrogen sulfide with myeloperoxidase. Br J Pharmacol 2014; 172:1516-32. [PMID: 24824874 DOI: 10.1111/bph.12769] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/24/2014] [Accepted: 04/22/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE The actions of hydrogen sulfide in human physiology have been extensively studied and, although it is an essential mediator of many biological functions, the underlying molecular mechanisms of its actions are ill-defined. To elucidate the roles of sulfide in inflammation, we have investigated its interactions with human myeloperoxidase (MPO), a major contributor to inflammatory oxidative stress. EXPERIMENTAL APPROACH The interactions of sulfide and MPO were investigated using electron paramagnetic resonance, electronic circular dichroism, UV-vis and stopped-flow spectroscopies. KEY RESULTS We found favourable reactions between sulfide and the native-ferric enzyme as well as the MPO redox intermediates, ferrous MPO, compound I and compound II. Sulfide was a potent reversible inhibitor of MPO enzymic activity with an IC50 of 1 µM. In addition, the measured second-order rate constants for the reactions of sulfide with compound I [k = (1.1 ± 0.06) × 10(6) M(-1) s(-1)] and compound II [k = (2.0 ± 0.03) × 10(5) M(-1) s(-1)] suggest that sulfide is a potential substrate for MPO in vivo. CONCLUSION AND IMPLICATIONS Endogenous levels of sulfide are likely to inhibit the activity of circulating and endothelium-bound MPO. The fully reversible inhibition suggests a mediatory role of sulfide on the oxidant-producing function of the enzyme. Furthermore, the efficient HOCl oxidation of sulfide to give polysulfides (recently recognized as important components of sulfide biology) together with MPO-catalysed sulfide oxidation and the lack of interaction between MPO and sulfide oxidation products, predict a modulatory role of MPO in sulfide signalling.
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Affiliation(s)
- Zoltán Pálinkás
- Department of Molecular Immunology and Toxicology, National Institute of Oncology, Budapest, Hungary
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