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Futagbi G, Otu PS, Abdul-Rahman M, Aidoo EK, Lo AC, Gyan BA, Afrane YA, Amoah LE. Association of TNF-Alpha, MBL2, NOS2, and G6PD with Malaria Outcomes in People in Southern Ghana. Genet Res (Camb) 2022; 2022:6686406. [PMID: 35291755 PMCID: PMC8901335 DOI: 10.1155/2022/6686406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/11/2022] [Accepted: 02/10/2022] [Indexed: 11/17/2022] Open
Abstract
Background One major issue that has set back the gains of the numerous malaria control interventions that national malaria control programs have implemented is asymptomatic malaria. Certain host genetic factors are known to influence symptomatic malaria; however, not much is known about how host genetics influences the acquisition of asymptomatic malaria. Methods Genomic DNA was extracted from whole blood collected from 60 symptomatic and 149 nonfebrile (asymptomatic, N = 109, and uninfected, N = 40) volunteers aged between 2 and 69 years from a high (Obom) and a low (Asutsuare) malaria transmission setting in Southern Ghana. Restriction fragment length polymorphism (RFLP) was used to determine polymorphisms at the MBL2 54, TNF-α 308, NOS2 954, and G6PD 202/376 gene loci. Results Polymorphisms at the MBL2 54 and TNF-α 308 loci were significantly different amongst the three categories of volunteers in both Asutsuare (p = 0.006) and Obom (p=0.05). In Asutsuare, a low malaria transmission area, the allele G has significantly higher odds (3.15) of supporting asymptomatic malaria as against symptomatic malaria. There were significantly higher odds of TNF-α genotype GA being associated with symptomatic malaria as against asymptomatic malaria in both sites, Obom (p=0.027) and Asutsuare (p=0.027). The allele B of the G6PD gene was more prevalent in symptomatic rather than asymptomatic parasite-infected individuals in both Obom (p=0.001) and Asutsuare (p=0.003). Conclusion Individuals in Southern Ghana carrying the TNF-α 308 GA genotype are more likely to exhibit symptoms of malaria when infected with the malaria parasite as opposed to harboring an asymptomatic infection. Also, the B allele of the G6PD gene is likely to prevent a P. falciparum-infected person from exhibiting symptoms and thereby promote asymptomatic parasite carriage.
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Affiliation(s)
- Godfred Futagbi
- Department of Animal Biology and Conservation Science, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Paulina S Otu
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
| | - Mubarak Abdul-Rahman
- Department of Pathology, University of Ghana Medical School, University of Ghana, Accra, Ghana
| | - Ebenezer K Aidoo
- Department of Medical Laboratory, Accra Technical University, Accra, Ghana
| | - Aminata C Lo
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- Department of Medical Parasitology, Faculty of Medicine, University Cheikh Anta Diop, Dakar, Senegal
| | - Ben A Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, University of Ghana Medical School, University of Ghana, Accra, Ghana
| | - Linda E Amoah
- Immunology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
- West Africa Center for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
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Moreira DR, Uberti ACMG, Gomes ARQ, Ferreira MES, da Silva Barbosa A, Varela ELP, Dolabela MF, Percário S. Dexamethasone increased the survival rate in Plasmodium berghei-infected mice. Sci Rep 2021; 11:2623. [PMID: 33514836 PMCID: PMC7846581 DOI: 10.1038/s41598-021-82032-7] [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: 09/17/2020] [Accepted: 01/11/2021] [Indexed: 01/30/2023] Open
Abstract
The present study aimed to evaluate the effects of dexamethasone on the redox status, parasitemia evolution, and survival rate of Plasmodium berghei-infected mice. Two-hundred and twenty-five mice were infected with Plasmodium berghei and subjected to stimulation or inhibition of NO synthesis. The stimulation of NO synthesis was performed through the administration of L-arginine, while its inhibition was made by the administration of dexamethasone. Inducible NO synthase (iNOS) inhibition by dexamethasone promoted an increase in the survival rate of P. berghei-infected mice, and the data suggested the participation of oxidative stress in the brain as a result of plasmodial infection, as well as the inhibition of brain NO synthesis, which promoted the survival rate of almost 90% of the animals until the 15th day of infection, with possible direct interference of ischemia and reperfusion syndrome, as seen by increased levels of uric acid. Inhibition of brain iNOS by dexamethasone caused a decrease in parasitemia and increased the survival rate of infected animals, suggesting that NO synthesis may stimulate a series of compensatory redox effects that, if overstimulated, may be responsible for the onset of severe forms of malaria.
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Affiliation(s)
- Danilo Reymão Moreira
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Ana Carolina Musa Gonçalves Uberti
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Antonio Rafael Quadros Gomes
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Michelli Erica Souza Ferreira
- grid.411204.20000 0001 2165 7632Laboratory of Pathophysiology and Therapeutic Research, Centro de Ciências Sociais Saúde e Tecnologia – CCSST, Federal University of Maranhão, Campus Avançado - Bom Jesus, Prédio de Medicina, Av. da Universidade, S/N, Imperatriz, MA 65915-240 Brazil
| | - Aline da Silva Barbosa
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Everton Luiz Pompeu Varela
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Maria Fani Dolabela
- grid.271300.70000 0001 2171 5249Institute of Health Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
| | - Sandro Percário
- grid.271300.70000 0001 2171 5249Oxidative Stress Research Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Corrêa, 01, Belém, PA 66075-110 Brazil
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Kinetic and Cross-Sectional Studies on the Genesis of Hypoargininemia in Severe Pediatric Plasmodium falciparum Malaria. Infect Immun 2019; 87:IAI.00655-18. [PMID: 30718287 DOI: 10.1128/iai.00655-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 01/05/2019] [Indexed: 12/12/2022] Open
Abstract
The low bioavailability of nitric oxide (NO) and its precursor, arginine, contributes to the microvascular pathophysiology of severe falciparum malaria. To better characterize the mechanisms underlying hypoargininemia in severe malaria, we measured the plasma concentrations of amino acids involved in de novo arginine synthesis in children with uncomplicated falciparum malaria (UM; n = 61), children with cerebral falciparum malaria (CM; n = 45), and healthy children (HC; n = 109). We also administered primed infusions of l-arginine uniformly labeled with 13C6 and 15N4 to 8 children with severe falciparum malaria (SM; age range, 4 to 9 years) and 7 healthy children (HC; age range, 4 to 8 years) to measure the metabolic flux of arginine, hypothesizing that arginine flux is increased in SM. Using two different tandem mass spectrometric methods, we measured the isotopic enrichment of arginine in plasma obtained at 0, 60, 90, 120, 150, and 180 min during the infusion. The plasma concentrations of glutamine, glutamate, proline, ornithine, citrulline, and arginine were significantly lower in UM and CM than in HC (P ≤ 0.04 for all pairwise comparisons). Of these, glutamine concentrations were the most markedly decreased: median, 457 μM (interquartile range [IQR], 400 to 508 μM) in HC, 300 μM (IQR, 256 to 365 μM) in UM, and 257 μM (IQR, 195 to 320 μM) in CM. Arginine flux during steady state was not significantly different in SM than in HC by the respective mass spectrometric methods: 93.2 μmol/h/kg of body weight (IQR, 84.4 to 129.3 μmol/h/kg) versus 88.0 μmol/h/kg (IQR, 73.0 to 102.2 μmol/h/kg) (P = 0.247) by the two mass spectrometric methods in SM and 93.7 μmol/h/kg (IQR, 79.1 to 117.8 μmol/h/kg) versus 81.0 μmol/h/kg (IQR, 75.9 to 88.6 μmol/h/kg) (P = 0.165) by the two mass spectrometric methods in HC. A limited supply of amino acid precursors for arginine synthesis likely contributes to the hypoargininemia and NO insufficiency in falciparum malaria in children.
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4
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Yu H, Chaimbault P, Clarot I, Chen Z, Leroy P. Labeling nitrogen species with the stable isotope 15N for their measurement by separative methods coupled with mass spectrometry: A review. Talanta 2019; 191:491-503. [DOI: 10.1016/j.talanta.2018.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/30/2018] [Accepted: 09/04/2018] [Indexed: 02/09/2023]
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Marealle AI, Siervo M, Wassel S, Bluck L, Prentice AM, Minzi O, Sasi P, Kamuhabwa A, Soka D, Makani J, Cox SE. A pilot study of a non-invasive oral nitrate stable isotopic method suggests that arginine and citrulline supplementation increases whole-body NO production in Tanzanian children with sickle cell disease. Nitric Oxide 2018; 74:19-22. [PMID: 29305240 PMCID: PMC5832986 DOI: 10.1016/j.niox.2017.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 11/25/2017] [Accepted: 12/29/2017] [Indexed: 12/24/2022]
Abstract
Background Low bioavailability of nitric oxide (NO) is implicated in the pathophysiology of sickle cell disease (SCD). We designed a nested pilot study to be conducted within a clinical trial testing the effects of a daily ready-to-use supplementary food (RUSF) fortified with arginine (Arg) and citrulline (Citr) vs. non-fortified RUSF in children with SCD. The pilot study evaluated 1) the feasibility of a non-invasive stable isotope method to measure whole-body NO production and 2) whether Arg+Citr supplementation was associated with increased whole-body NO production. Subjects Twenty-nine children (70% male, 9–11years, weight 16.3–31.3 kg) with SCD. Methods Sixteen children received RUSF+Arg/Citr (Arg, 0.2 g/kg/day; Citr, 0.1 g/kg/day) in combination with daily chloroquine (50 mg) and thirteen received the base RUSF in combination with weekly chloroquine (150 mg). Plasma amino acids were assessed using ion-exchange elution (Biochrom-30, Biochrom, UK) and whole-body NO production was measured using a non-invasive stable isotopic method. Results The RUSF+Arg/Citr intervention increased plasma arginine (P = .02) and ornithine (P = .003) and decreased the ratio of asymmetric dimethylarginine to arginine (P = .01), compared to the base RUSF. A significant increase in whole-body NO production was observed in the RUSF-Arg/Citr group compared to baseline (weight-adjusted systemic NO synthesis 3.38 ± 2.29 μmol/kg/hr vs 2.35 ± 1.13 μmol/kg/hr, P = .04). No significant changes were detected in the base RUSF group (weight-adjusted systemic NO synthesis 2.64 ± 1.14 μmol/kg/hr vs 2.53 ± 1.12 μmol/kg/hr, P = .80). Conclusions The non-invasive stable isotopic method was acceptable and the results provided supporting evidence that Arg/Citr supplementation may increase systemic NO synthesis in children with SCD. This method for measuring whole-body NO synthesis is feasible in young children. The isotopic decay of the stable isotope tracer demonstrated good linear fit. Arginine and citrulline supplementation may increase whole-body NO synthesis.
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Affiliation(s)
- Alphonce I Marealle
- Muhimbili Wellcome Programme, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania; School of Pharmacy, Department of Clinical Pharmacy & Pharmacology, Muhimbili University of Health & Allied Sciences, Dar es Salaam, Tanzania
| | - Mario Siervo
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, UK
| | | | - Les Bluck
- MRC Human Nutrition Research, Cambridge, UK
| | - Andrew M Prentice
- MRC Unit, The Gambia and MRC International Nutrition Group, London School of Hygiene & Tropical Medicine, London, UK
| | - Omary Minzi
- School of Pharmacy, Department of Clinical Pharmacy & Pharmacology, Muhimbili University of Health & Allied Sciences, Dar es Salaam, Tanzania
| | - Philip Sasi
- School of Medicine, Department of Clinical Pharmacology, Muhimbili University of Health & Allied Sciences, Dar es Salaam, Tanzania
| | - Appolinary Kamuhabwa
- School of Pharmacy, Department of Clinical Pharmacy & Pharmacology, Muhimbili University of Health & Allied Sciences, Dar es Salaam, Tanzania
| | - Deogratias Soka
- Muhimbili Wellcome Programme, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Julie Makani
- Muhimbili Wellcome Programme, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Sharon E Cox
- Muhimbili Wellcome Programme, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania; School of Tropical Medicine & Global Health, Nagasaki University, Nagasaki, Japan; Dept of Population Health, London School of Hygiene & Tropical Medicine, London, UK.
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Alkaitis MS, Wang H, Ikeda AK, Rowley CA, MacCormick IJC, Chertow JH, Billker O, Suffredini AF, Roberts DJ, Taylor TE, Seydel KB, Ackerman HC. Decreased Rate of Plasma Arginine Appearance in Murine Malaria May Explain Hypoargininemia in Children With Cerebral Malaria. J Infect Dis 2017; 214:1840-1849. [PMID: 27923948 DOI: 10.1093/infdis/jiw452] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/16/2016] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Plasmodium infection depletes arginine, the substrate for nitric oxide synthesis, and impairs endothelium-dependent vasodilation. Increased conversion of arginine to ornithine by parasites or host arginase is a proposed mechanism of arginine depletion. METHODS We used high-performance liquid chromatography to measure plasma arginine, ornithine, and citrulline levels in Malawian children with cerebral malaria and in mice infected with Plasmodium berghei ANKA with or without the arginase gene. Heavy isotope-labeled tracers measured by quadrupole time-of-flight liquid chromatography-mass spectrometry were used to quantify the in vivo rate of appearance and interconversion of plasma arginine, ornithine, and citrulline in infected mice. RESULTS Children with cerebral malaria and P. berghei-infected mice demonstrated depletion of plasma arginine, ornithine, and citrulline. Knock out of Plasmodium arginase did not alter arginine depletion in infected mice. Metabolic tracer analysis demonstrated that plasma arginase flux was unchanged by P. berghei infection. Instead, infected mice exhibited decreased rates of plasma arginine, ornithine, and citrulline appearance and decreased conversion of plasma citrulline to arginine. Notably, plasma arginine use by nitric oxide synthase was decreased in infected mice. CONCLUSIONS Simultaneous arginine and ornithine depletion in malaria parasite-infected children cannot be fully explained by plasma arginase activity. Our mouse model studies suggest that plasma arginine depletion is driven primarily by a decreased rate of appearance.
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Affiliation(s)
- Matthew S Alkaitis
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville.,Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Headington
| | - Honghui Wang
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - Allison K Ikeda
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville
| | - Carol A Rowley
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville
| | - Ian J C MacCormick
- Department of Eye and Vision Science, University of Liverpool.,Centre for Clinical Brain Sciences, University of Edinburgh.,Malawi-Liverpool-Wellcome Trust Clinical Research Programme
| | - Jessica H Chertow
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville
| | | | - Anthony F Suffredini
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland
| | - David J Roberts
- Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Headington.,National Health Service Blood and Transplant, John Radcliffe Hospital, Oxford, United Kingdom
| | - Terrie E Taylor
- Michigan State University, East Lansing.,Blantyre Malaria Project, Malawi
| | - Karl B Seydel
- Michigan State University, East Lansing.,Blantyre Malaria Project, Malawi
| | - Hans C Ackerman
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville
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Lima-Junior JDC, Pratt-Riccio LR. Major Histocompatibility Complex and Malaria: Focus on Plasmodium vivax Infection. Front Immunol 2016; 7:13. [PMID: 26858717 PMCID: PMC4728299 DOI: 10.3389/fimmu.2016.00013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/12/2016] [Indexed: 01/13/2023] Open
Abstract
The importance of host and parasite genetic factors in malaria resistance or susceptibility has been investigated since the middle of the last century. Nowadays, of all diseases that affect man, malaria still plays one of the highest levels of selective pressure on human genome. Susceptibility to malaria depends on exposure profile, epidemiological characteristics, and several components of the innate and adaptive immune system that influences the quality of the immune response generated during the Plasmodium lifecycle in the vertebrate host. But it is well known that the parasite's enormous capacity of genetic variation in conjunction with the host genetics polymorphism is also associated with a wide spectrum of susceptibility degrees to complicated or severe forms of the disease. In this scenario, variations in genes of the major histocompatibility complex (MHC) associated with host resistance or susceptibility to malaria have been identified and used as markers in host-pathogen interaction studies, mainly those evaluating the impact on the immune response, acquisition of resistance, or increased susceptibility to infection or vulnerability to disease. However, due to the intense selective pressure, number of cases, and mortality rates, the majority of the reported associations reported concerned Plasmodium falciparum malaria. Studies on the MHC polymorphism and its association with Plasmodium vivax, which is the most widespread Plasmodium and the most prevalent species outside the African continent, are less frequent but equally important. Despite punctual contributions, there are accumulated evidences of human genetic control in P. vivax infection and disease. Herein, we review the current knowledge in the field of MHC and derived molecules (HLA Class I, Class II, TNF-α, LTA, BAT1, and CTL4) regarding P. vivax malaria. We discuss particularly the results of P. vivax studies on HLA class I and II polymorphisms in relation to host susceptibility, naturally acquired immune response against specific antigens and the implication of this knowledge to overcome the parasite immune evasion. Finally, the potential impact of such polymorphisms on the development of vaccine candidate antigens against P. vivax will be studied.
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Inducible nitric oxide synthase (iNOS) regulatory region variation in non-human primates. INFECTION GENETICS AND EVOLUTION 2015; 31:236-44. [PMID: 25675838 DOI: 10.1016/j.meegid.2015.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/07/2015] [Accepted: 01/19/2015] [Indexed: 01/26/2023]
Abstract
Inducible nitric oxide synthase (iNOS) is an enzyme that plays a key role in intracellular immune response against respiratory infections. Since various species of nonhuman primates exhibit different levels of susceptibility to infectious respiratory diseases, and since variation in regulatory regions of genes is thought to play a key role in expression levels of genes, two candidate regulatory regions of iNOS were mapped, sequenced, and compared across five species of nonhuman primates: African green monkeys (Chlorocebus sabaeus), pig-tailed macaques (Macaca nemestrina), cynomolgus macaques (Macaca fascicularis), Indian rhesus macaques (Macaca mulatta), and Chinese rhesus macaques (M. mulatta). In addition, we conducted an in silico analysis of the transcription factor binding sites associated with genetic variation in these two candidate regulatory regions across species. We found that only one of the two candidate regions showed strong evidence of involvement in iNOS regulation. Specifically, we found evidence of 13 conserved binding site candidates linked to iNOS regulation: AP-1, C/EBPB, CREB, GATA-1, GATA-3, NF-AT, NF-AT5, NF-κB, KLF4, Oct-1, PEA3, SMAD3, and TCF11. Additionally, we found evidence of interspecies variation in binding sites for several regulatory elements linked to iNOS (GATA-3, GATA-4, KLF6, SRF, STAT-1, STAT-3, OLF-1 and HIF-1) across species, especially in African green monkeys relative to other species. Given the key role of iNOS in respiratory immune response, the findings of this study might help guide the direction of future studies aimed to uncover the molecular mechanisms underlying the increased susceptibility of African green monkeys to several viral and bacterial respiratory infections.
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NOS2 variants reveal a dual genetic control of nitric oxide levels, susceptibility to Plasmodium infection, and cerebral malaria. Infect Immun 2013; 82:1287-95. [PMID: 24379293 DOI: 10.1128/iai.01070-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Nitric oxide (NO) is a proposed component of malaria pathogenesis, and the inducible nitric oxide synthase gene (NOS2) has been associated to malaria susceptibility. We analyzed the role of NOS2 polymorphisms on NO bioavailability and on susceptibility to infection, Plasmodium carrier status and clinical malaria. Two distinct West African sample collections were studied: a population-based collection of 1,168 apparently healthy individuals from the Príncipe Island and a hospital-based cohort of 269 Angolan children. We found that two NOS2 promoter single-nucleotide polymorphism (SNP) alleles associated to low NO plasma levels in noninfected individuals were also associated to reduced risk of pre-erythrocytic infection as measured anti-CSP antibody levels (6.25E-04 < P < 7.57E-04). In contrast, three SNP alleles within the NOS2 cistronic region conferring increased NO plasma levels in asymptomatic carriers were strongly associated to risk of parasite carriage (8.00E-05 < P < 7.90E-04). Notwithstanding, three SNP alleles in this region protected from cerebral malaria (7.90E-4 < P < 4.33E-02). Cohesively, the results revealed a dual regimen in the genetic control of NO bioavailability afforded by NOS2 depending on the infection status. NOS2 promoter variants operate in noninfected individuals to decrease both NO bioavailability and susceptibility to pre-erythrocytic infection. Conversely, NOS2 cistronic variants (namely, rs6505469) operate in infected individuals to increase NO bioavailability and confer increased susceptibility to unapparent infection but protect from cerebral malaria. These findings corroborate the hypothesis that NO anti-inflammatory properties impact on different steps of malaria pathogenesis, explicitly by favoring infection susceptibility and deterring severe malaria syndromes.
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Inhaled nitric oxide and cerebral malaria: basis of a strategy for buying time for pharmacotherapy. Pediatr Infect Dis J 2012; 31:e250-4. [PMID: 22760538 DOI: 10.1097/inf.0b013e318266c113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
There are approximately 225-600 million new malaria infections worldwide annually, with severe and cerebral malaria representing major causes of death internationally. The role of nitric oxide (NO) in the host response in cerebral malaria continues to be elucidated, with numerous known functions relating to the cytokine, endovascular and cellular responses to infection with Plasmodium falciparum. Evidence from diverse modes of inquiry suggests NO to be critical in modulating the immune response and promoting survival in patients with cerebral malaria. This line of investigation has culminated in the approval of 2 phase II randomized prospective clinical trials in Uganda studying the use of inhaled NO as adjuvant therapy in children with severe malaria. The strategy underlying both trials is to use the sytemic antiinflammatory properties of inhaled NO to "buy time" for chemical antiparasite therapy to lower the parasite load. This article reviews the nexus of malaria and NO biology with a primary focus on cerebral malaria in humans.
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Siervo M, Stephan BCM, Feelisch M, Bluck LJC. Measurement of in vivo nitric oxide synthesis in humans using stable isotopic methods: a systematic review. Free Radic Biol Med 2011; 51:795-804. [PMID: 21672626 DOI: 10.1016/j.freeradbiomed.2011.05.032] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 04/22/2011] [Accepted: 05/25/2011] [Indexed: 11/16/2022]
Abstract
Stable isotopic methods are considered the "gold standard" for the measurement of rates of in vivo NO production. However, values reported for healthy human individuals differ by more than 1 order of magnitude. The reason for the apparent variability in NO production is unclear. The primary aim of this review was to evaluate and compare the rates of in vivo NO production in health and disease using stable isotope methods. Articles were retrieved using the PubMed electronic database. Information on concentrations, isotopic enrichments of fluxes, and conversion rates of molecules involved in the NO metabolic pathway was extracted from selected articles; 35 articles were included in the final analysis. Three protocols were identified, including the arginine-citrulline, the arginine-nitrate, and the oxygen-nitrate protocols. The arginine-citrulline protocol showed a wider variability compared to the arginine-nitrate and oxygen-nitrate protocols. The direction of the association between disease state and rate of NO production was essentially determined by the etiopathogenesis of the disorder (inflammatory, metabolic, vascular). Considerable variation in methodologies used to assess whole-body NO synthesis in humans exists. The precision of several aspects of the techniques and the validity of some assumptions made remain unknown, and there is a paucity of information about physiological rates of NO production from childhood over adolescence to old age.
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Affiliation(s)
- M Siervo
- Elsie Widdowson Laboratory, MRC Human Nutrition Research, Cambridge CB1 9NL, UK.
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