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Sánchez AG, Ibargoyen MN, Mastrogiovanni M, Radi R, Keszenman DJ, Peluffo RD. Fast and biphasic 8-nitroguanine production from guanine and peroxynitrite. Free Radic Biol Med 2022; 193:474-484. [PMID: 36332879 DOI: 10.1016/j.freeradbiomed.2022.10.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/12/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Guanine (Gua), among purines, is a preferred oxidation/nitration target because of its low one-electron redox potential. The reactive oxygen/nitrogen species peroxynitrite (ONOO-), produced in vivo by the reaction between nitric oxide (•NO) and superoxide radical (O2•‒), is responsible for several oxidative modifications in biomolecules, including nitration, nitrosation, oxidation, and peroxidation. In particular, the nitration of Gua, although detected, as well as its reaction kinetics have been seldom investigated. Thus, we studied the concentration- and temperature-dependent formation of 8-nitroguanine (8-NitroGua) in phosphate buffer (pH 7.40) using stopped-flow spectrophotometry. Traces showed a biexponential behavior, with best-fit rate constants: kfast = 4.4 s-1 and kslow = 0.41 s-1 (30 °C, 400 μM both Gua and ONOO-). kfast increased linearly with the concentration of both reactants whereas kslow was concentration-independent. Linear regression analysis of kfast as a function of Gua and ONOO- concentration yielded values of 2.5-6.3 × 103 M-1s-1 and 1.5-3.5 s-1 for the second-order (slope) and first-order (ordinate) rate constants, respectively (30 °C). Since ONOO- is a short-lived species, its decay kinetics was also taken into account for this analysis. The 8-NitroGua product was stable for at least 4 h, so no spontaneous denitration was observed. Stopped-flow assays using antioxidants and free-radical scavengers suggested a mixed direct/indirect reaction mechanism for 8-NitroGua formation. Gua nitration by ONOO- was also observed in the presence of physiologically relevant CO2 concentrations. The reaction product identity, its yield (∼4.2%, with 400 μM ONOO- and 200 μM Gua), and the reaction mechanism were unequivocally determined by HPLC-MS/MS experiments. In conclusion, 8-NitroGua production at physiologic pH reached significant levels in a few hundred milliseconds, suggesting that the process might be kinetically relevant in vivo and can likely cause permanent nitrative damage to DNA bases.
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Affiliation(s)
- Ana G Sánchez
- Grupo de Biofisicoquímica, Departamento de Ciencias Biológicas, CENUR Litoral Norte, Universidad de la República, Rivera 1350, 50000, Salto, Uruguay
| | - M Natalia Ibargoyen
- Grupo de Biofisicoquímica, Departamento de Ciencias Biológicas, CENUR Litoral Norte, Universidad de la República, Rivera 1350, 50000, Salto, Uruguay
| | - Mauricio Mastrogiovanni
- Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Avda. General Flores 2125, 11800, Montevideo, Uruguay
| | - Rafael Radi
- Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Avda. General Flores 2125, 11800, Montevideo, Uruguay
| | - Deborah J Keszenman
- Grupo de Biofisicoquímica, Departamento de Ciencias Biológicas, CENUR Litoral Norte, Universidad de la República, Rivera 1350, 50000, Salto, Uruguay
| | - R Daniel Peluffo
- Grupo de Biofisicoquímica, Departamento de Ciencias Biológicas, CENUR Litoral Norte, Universidad de la República, Rivera 1350, 50000, Salto, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Avda. General Flores 2125, 11800, Montevideo, Uruguay; Department of Pharmacology, Physiology and Neuroscience, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, Newark, NJ, 07103, USA.
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Jackson EK, Menshikova EV, Ritov VB, Gillespie DG, Mi Z. Biochemical Pathways of 8-Aminoguanine Production In Sprague-Dawley and Dahl Salt-Sensitive Rats. Biochem Pharmacol 2022; 201:115076. [PMID: 35551915 DOI: 10.1016/j.bcp.2022.115076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/30/2022] [Accepted: 05/03/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND 8-Aminoguanine exerts natriuretic and antihypertensive activity. Whether and how "free" 8-aminoguanine exists in vivo is unclear. Because 8-nitroguanosine is naturally occurring, we tested the hypothesis that 8-aminoguanine can arise from: pathway 1, 8-nitroguanosine→8-aminoguanosine→8-aminoguanine; and pathway 2, 8-nitroguanosine→8-nitroguanine→8-aminoguanine. METHODS 8-Aminoguanine biosynthesis was explored in rats using renal microdialysis, mass spectrometry and enzyme kinetics. RESULTS In Sprague-Dawley rats, 8-nitroguanosine infusions increased kidney levels of 8-nitroguanine, 8-aminoguanosine and 8-aminoguanine; 8-nitroguanine infusions increased 8-aminoguanine. Purine nucleoside phosphorylase (PNPase) converted 8-nitroguanosine to 8-nitroguanine and 8-aminoguanosine to 8-aminoguanine. Forodesine (PNPase inhibitor) reduced metabolism of 8-nitroguanosine by pathway 2 and shunted metabolism of 8-nitroguanosine to 8-aminoguanosine. In Dahl salt-sensitive rats, 8-nitroguanosine infusions increased kidney levels of 8-nitroguanine, 8-aminoguanosine and 8-aminoguanine. These results indicate that both pathways 1 and 2 participate in the biosynthesis of 8-aminoguanine in Sprague-Dawley and Dahl rats. Endogenous 8-aminoguanine in kidneys and urine were elevated many-fold in Dahl, compared to Sprague-Dawley, rats. The increased levels of 8-aminoguanine in Dahl rats were not due to alterations in pathways 1 and 2 but were associated with increased urine levels of endogenous 8-nitroguanosine suggesting that the "upstream" production of 8-nitroguanosine was increased in Dahl rats. Dahl rats are known to have high levels of peroxynitrite, and peroxynitrite is known to nitrate guanosine in biomolecules. Here we confirm that a peroxynitrite donor increases kidney levels of 8-aminoguanine. CONCLUSION 8-Aminoguanine occurs naturally via two distinct pathways and kidney levels of 8-aminoguanine are increased in Dahl rats, likely due to increased production of 8-nitroguanosine, a by-product of peroxynitrite chemistry.
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Affiliation(s)
- Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219.
| | - Elizabeth V Menshikova
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Vladimir B Ritov
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Delbert G Gillespie
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Zaichuan Mi
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
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Wan FC, Zhang C, Jin Q, Wei C, Zhao HB, Zhang XL, You W, Liu XM, Liu GF, Liu YF, Tan XW. Protective effects of astaxanthin on lipopolysaccharide-induced inflammation in bovine endometrial epithelial cells†. Biol Reprod 2021; 102:339-347. [PMID: 31566218 DOI: 10.1093/biolre/ioz187] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 08/21/2019] [Accepted: 09/12/2019] [Indexed: 01/20/2023] Open
Abstract
Astaxanthin (AST), a natural antioxidant carotenoid, has been shown to exert anti-inflammatory effects. However, to our knowledge, no study has specifically addressed the potential protective effects of AST against bovine endometritis. The purpose of this study was to examine whether treatment with AST could protect endometrial epithelial cells against lipopolysaccharide (LPS)-induced inflammatory injury. Treatment of bovine endometrial (BEND) epithelial cell line with AST reduced LPS-induced production of interleukin-6 and tumor necrosis factor-alpha, increased the cellular activity of superoxide dismutase and catalase, decreased the proportion of apoptotic cells, and promoted the production of insulin-like growth factor and epithelial growth factor. The effects of AST were mediated through the downregulation of B-cell lymphoma 2 (Bcl-2) associated X, apoptosis regulator (Bax), and cleaved caspase-3 and through the upregulation of Bcl-2. Moreover, AST significantly increased the expression of the tight junction proteins (TJP) claudin, cadherin-1, and TJP1, which play an essential role in the maintenance of host endometrial defense barrier against pathogen infection. Collectively, these results demonstrated that treatment with AST protected against oxidative stress, prevented cell apoptosis, promoted BEND cells viability, and increased the production of growth factors, in addition to activating the endometrial defense barrier. Therefore, AST is a promising therapeutic agent for the prevention and treatment of endometritis. This finding is of utmost importance in the present times when the excessive use of antibiotics has resulted in the development of antibiotic-resistant bacteria.
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Affiliation(s)
- Fa-Chun Wan
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China.,College of Life Sciences, Shandong Normal University, Ji'nan City, China
| | - Chen Zhang
- College of Life Sciences, Shandong Normal University, Ji'nan City, China
| | - Qing Jin
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Chen Wei
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Hong-Bo Zhao
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Xiang-Lun Zhang
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Wei You
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Xiao-Mu Liu
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Gui-Fen Liu
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Yi-Fan Liu
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
| | - Xiu-Wen Tan
- Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji'nan City, China.,Shandong Key Lab of Animal Disease Control and Breeding, Ji'nan City, China.,Shandong Provincial Testing Center of Beef Cattle Performance, Ji'nan City, China
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Verigos KE, Sagredou S, Orfanakos K, Dalezis P, Trafalis DT. 8-Hydroxy-2'-Deoxyguanosine and 8-Nitroguanine Production and Detection in Blood Serum of Breast Cancer Patients in Response to Postoperative Complementary External Ionizing Irradiation of Normal Tissues. Dose Response 2021; 18:1559325820982172. [PMID: 33424517 PMCID: PMC7758665 DOI: 10.1177/1559325820982172] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/18/2020] [Accepted: 11/25/2020] [Indexed: 11/16/2022] Open
Abstract
It is widely known that ionizing irradiation is strongly linked to the production of reactive oxygen (ROS) and nitrative species (RNS) through which DNA damage products like 8-hydroxy-2-deoxyguanosine (8-OHdG) and 8-nitroguanine (8-NG) are generated, respectively. In the present study, we aimed to investigate the formation of 8-OHdG and 8-NG upon irradiation and to further explore whether alterations in their concentration levels are related to the administered radiation doses and exposure time. Our research work was conducted in blood serum samples collected from 33 breast cancer patients who received adjuvant radiotherapy. The detection of 8-OHdG and 8-NG was assessed by enzyme-linked immunosorbent assay. Our results suggest that both, 8-OHdG and 8-NG, were formed during the radiation regimen. Significant correlations with radiation dose were also demonstrated by the dose-response curves of 8-OHdG and 8-NG, fitted by logarithmic distribution and polynomial regression, respectively. More precisely, 8-OHdG and 8-NG concentrations (ng/mL) were considerably increased when patients received ionizing radiation up to 30 Gy whereas irradiation over 30 Gy did not induce any further increases. The current study supports a) the production of 8-OHdG and 8-NG during radiotherapy and b) significant correlations between either 8-OHdG or 8-NG levels and radiation doses, indicating a radiation-dose-dependent relationship.
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Affiliation(s)
- Kosmas E Verigos
- Laboratory of Pharmacology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Department of Radiation Therapy, 401 General Military Hospital, Athens, Greece
| | - Sofia Sagredou
- Laboratory of Pharmacology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Kyriakos Orfanakos
- Laboratory of Pharmacology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Radiation Therapy Clinic-A, "Metaxa" Cancer Hospital, Piraeus, Greece
| | - Panayiotis Dalezis
- Laboratory of Pharmacology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios T Trafalis
- Laboratory of Pharmacology, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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Ahmed N, Chakrabarty A, Guengerich FP, Chowdhury G. Protective Role of Glutathione against Peroxynitrite-Mediated DNA Damage During Acute Inflammation. Chem Res Toxicol 2020; 33:2668-2674. [PMID: 32894672 DOI: 10.1021/acs.chemrestox.0c00299] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Inflammation is an immune response to protect against various types of infections. When unchecked, acute inflammation can be life-threatening, as seen with the current coronavirus pandemic. Strong oxidants, such as peroxynitrite produced by immune cells, are major mediators of the inflammation-associated pathogenesis. Cellular thiols play important roles in mitigating inflammation-associated macromolecular damage including DNA. Herein, we have demonstrated a role of glutathione (GSH) and other thiols in neutralizing the effect of peroxynitrite-mediated DNA damage through stable GSH-DNA adduct formation. Our observation supports the use of thiol supplements as a potential therapeutic strategy against severe COVID-19 cases and a Phase II (NCT04374461) open-label clinical trial launched in early May 2020 by the Memorial Sloan Kettering Cancer Center.
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Affiliation(s)
| | | | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, United States
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