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Massimo G, Khambata RS, Chapman T, Birchall K, Raimondi C, Shabbir A, Dyson N, Rathod K, Borghi C, Ahluwalia A. Corrigendum to "Natural mutations of human XDH promote the nitrite (NO 2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health?" [Redox Biol. 4 (67) (2023) 102864]. Redox Biol 2023; 67:102925. [PMID: 37867029 PMCID: PMC10638451 DOI: 10.1016/j.redox.2023.102925] [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: 10/24/2023] Open
Affiliation(s)
- G Massimo
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - R S Khambata
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - T Chapman
- LifeArc, Accelerator Building Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - K Birchall
- LifeArc, Accelerator Building Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - C Raimondi
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - A Shabbir
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Nicki Dyson
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - K Rathod
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - C Borghi
- Department of Medical and Surgical Sciences, Faculty of Medicine, University of Bologna, Via Massarenti, N.9, 40138, Italy
| | - A Ahluwalia
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.
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Massimo G, Khambata RS, Chapman T, Birchall K, Raimondi C, Shabbir A, Dyson N, Rathod KS, Borghi C, Ahluwalia A. Natural mutations of human XDH promote the nitrite (NO 2-)-reductase capacity of xanthine oxidoreductase: A novel mechanism to promote redox health? Redox Biol 2023; 67:102864. [PMID: 37713777 PMCID: PMC10511815 DOI: 10.1016/j.redox.2023.102864] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 08/06/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/17/2023] Open
Abstract
Several rare genetic variations of human XDH have been shown to alter xanthine oxidoreductase (XOR) activity leading to impaired purine catabolism. However, XOR is a multi-functional enzyme that depending upon the environmental conditions also expresses oxidase activity leading to both O2·- and H2O2 and nitrite (NO2-) reductase activity leading to nitric oxide (·NO). Since these products express important, and often diametrically opposite, biological activity, consideration of the impact of XOR mutations in the context of each aspect of the biochemical activity of the enzyme is needed to determine the potential full impact of these variants. Herein, we show that known naturally occurring hXDH mutations do not have a uniform impact upon the biochemical activity of the enzyme in terms of uric acid (UA), reactive oxygen species (ROS) and nitric oxide ·NO formation. We show that the His1221Arg mutant, in the presence of xanthine, increases UA, O2·- and NO generation compared to the WT, whilst the Ile703Val increases UA and ·NO formation, but not O2·-. We speculate that this change in the balance of activity of the enzyme is likely to endow those carrying these mutations with a harmful or protective influence over health that may explain the current equipoise underlying the perceived importance of XDH mutations. We also show that, in presence of inorganic NO2-, XOR-driven O2·- production is substantially reduced. We suggest that targeting enzyme activity to enhance the NO2--reductase profile in those carrying such mutations may provide novel therapeutic options, particularly in cardiovascular disease.
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Affiliation(s)
- G Massimo
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - R S Khambata
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - T Chapman
- LifeArc, Accelerator Building Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - K Birchall
- LifeArc, Accelerator Building Open Innovation Campus, Stevenage, SG1 2FX, UK
| | - C Raimondi
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - A Shabbir
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Nicki Dyson
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - K S Rathod
- William Harvey Research Institute, Barts & the London Faculty of Medicine & Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - C Borghi
- Department of Medical and Surgical Sciences, Faculty of Medicine, University of Bologna, Via Massarenti, N.9, 40138, Italy
| | - A Ahluwalia
- Department of Medical and Surgical Sciences, Faculty of Medicine, University of Bologna, Via Massarenti, N.9, 40138, Italy.
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Shabbir A, Lau C, Rathod KS, Chhetri I, Haque A, Godec T, Khambata RS, Kapil V, Ahluwalia A. Inorganic nitrate attenuates the systemic inflammatory response in typhoid vaccine-induced endothelial dysfunction in healthy volunteers. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.3009] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Inflammatory responses underlie the development of endothelial dysfunction in CVD, however, therapeutics that might target this pathway have not been forthcoming. A key pathogenic mechanism mediating endothelial dysfunction is a reduction in bioavailable (eNOS-derived) nitric oxide (NO). Activation of the non-canonical pathway for in-vivo NO generation might offer an approach to improve NO levels and recover vascular function in pre-clinical models of CVD. Whether this might occur in humans is unknown.
Purpose
We hypothesize that consumption of inorganic nitrate will lead to increases in bioavailable NO and thus attenuate the inflammatory pathways leading to typhoid vaccine-induced endothelial dysfunction in healthy volunteers.
Methods
Healthy male volunteers were recruited (n=78) and randomized to receive either beetroot juice containing 8–10mmol nitrate or placebo (nitrate-deplete) juice once daily for 6 days. Participants underwent serial measurements of BP, FMD and GTN-induced brachial artery dilatation, and haematology and biochemistry, before and after typhoid vaccination. Blood, urine and saliva nitrite and nitrate were quantified using ozone chemiluminescence, and leukocyte flow cytometry analysis was conducted.
Results
8-hours post-vaccine endothelial function was depressed in placebo-treated volunteers, however this was prevented in nitrate-treated volunteers. This dysfunction was due to impaired endothelial function since responses to GTN were unaffected either by vaccination or dietary intervention (p=0.981). Dietary nitrate resulted in an increase in plasma (p<0.0001), urine (p=0.0006) and saliva (p<0.0001) nitrate, and urine (p=0.0354) and saliva (p<0.0001) nitrite levels. There was a reduction in the proportions of CD14++/CD16+intermediate monocytes in nitrate-treated participants after vaccine (p=0.016, change from baseline between groups). In the nitrate-treated group, less CD14++/CD16+ intermediate monocyte CD62L expression was identified post-vaccine (p=0.0122), compared to placebo, with no difference in soluble plasma CD62L between groups (p=0.875). CD11b median fluorescence intensity was increased in CD3+/CD4+ T-lymphocytes in nitrate-treated volunteers (p=0.0095).
Conclusions
Dietary nitrate reduced BP, as previously shown, indicating efficacy of the intervention. Importantly, we also now show for the first time that inorganic nitrate suppresses the systemic inflammatory response, specifically by reducing the numbers and activation state of CD14++/CD16+ intermediate monocytes. Furthermore, an increased expression of CD3+/CD4+ T-cell CD11b and preserved FMD in healthy volunteers treated with nitrate, suggests an anti-inflammatory phenotype, induced by the intervention, leading to improved endothelial function. Inorganic dietary nitrate modulates endothelial function through the attenuation of inflammatory responses and may be of potential therapeutic benefit in patients with established CAD.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- A Shabbir
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - C Lau
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - K S Rathod
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - I Chhetri
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - A Haque
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - T Godec
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - R S Khambata
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - V Kapil
- St Bartholomews and Queen Mary University, London, United Kingdom
| | - A Ahluwalia
- St Bartholomews and Queen Mary University, London, United Kingdom
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Kapil V, Khambata RS, Jones DA, Rathod K, Primus C, Massimo G, Fukuto JM, Ahluwalia A. The Noncanonical Pathway for In Vivo Nitric Oxide Generation: The Nitrate-Nitrite-Nitric Oxide Pathway. Pharmacol Rev 2020; 72:692-766. [DOI: 10.1124/pr.120.019240] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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