Publications by authors named "Christopher R Dunston"

10 Publications

  • Page 1 of 1

Addition of PLA2 to CRP enhances sepsis diagnosis.

J Infect 2016 10 22;73(4):386-8. Epub 2016 Jul 22.

Mologic Ltd, Thurleigh, Bedfordshire, UK.

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http://dx.doi.org/10.1016/j.jinf.2016.07.009DOI Listing
October 2016

CD4(+) T cell surface alpha enolase is lower in older adults.

Mech Ageing Dev 2015 Dec 1;152:56-62. Epub 2015 Oct 1.

Life and Health Sciences, Aston Research Centre for Healthy Ageing, Aston University, Birmingham B4 7ET, UK. Electronic address:

To identify novel cell ageing markers in order to gain insight into ageing mechanisms, we adopted membrane enrichment and comparison of the CD4(+) T cell membrane proteome (purified by cell surface labelling using Sulfo-NHS-SS-Biotin reagent) between healthy young (n=9, 20-25 years) and older (n=10; 50-70 years) male adults. Following two-dimensional gel electrophoresis (2DE) to separate pooled membrane proteins in triplicates, the identity of protein spots with age-dependent differences (p<0.05 and >1.4 fold difference) was determined using liquid chromatography-mass spectrometry (LC-MS/MS). Seventeen protein spot density differences (ten increased and seven decreased in the older adult group) were observed between young and older adults. From spot intensity analysis, CD4(+) T cell surface α-enolase was decreased in expression by 1.5 fold in the older age group; this was verified by flow cytometry (n=22) and qPCR with significantly lower expression of cellular α-enolase mRNA and protein compared to young adult CD4(+) T cells (p<0.05). In an independent age-matched case-control study, lower CD4(+) T cell surface α-enolase expression was observed in age-matched patients with cardiovascular disease (p<0.05). An immune-modulatory role has been proposed for surface α-enolase and our findings of decreased expression suggest that deficits in surface α-enolase merit investigation in the context of immune dysfunction during ageing and vascular disease.
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http://dx.doi.org/10.1016/j.mad.2015.09.005DOI Listing
December 2015

Improving T cell-induced response to subunit vaccines: opportunities for a proteomic systems approach.

J Pharm Pharmacol 2015 Mar 23;67(3):290-9. Epub 2015 Feb 23.

Life & Health Sciences, Aston University, Birmingham, West Midlands, UK; Mologic, Bedford Technology Park, Thurleigh, Bedfordshire, MK44 2YP.

Unlabelled: Prophylactic vaccines are an effective strategy to prevent development of many infectious diseases. With new and re-emerging infections posing increasing risks to food stocks and the health of the population in general, there is a need to improve the rationale of vaccine development. One key challenge lies in development of an effective T cell-induced response to subunit vaccines at specific sites and in different populations.

Objectives: In this review, we consider how a proteomic systems-based approach can be used to identify putative novel vaccine targets, may be adopted to characterise subunit vaccines and adjuvants fully.

Key Findings: Despite the extensive potential for proteomics to aid our understanding of subunit vaccine nature, little work has been reported on identifying MHC 1-binding peptides for subunit vaccines generating T cell responses in the literature to date.

Summary: In combination with predictive and structural biology approaches to mapping antigen presentation, proteomics offers a powerful and as yet un-tapped addition to the armoury of vaccine discovery to predict T-cell subset responses and improve vaccine design strategies.
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http://dx.doi.org/10.1111/jphp.12383DOI Listing
March 2015

Thioredoxin as a putative biomarker and candidate target in age-related immune decline.

Biochem Soc Trans 2014 Aug;42(4):922-7

*School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, U.K.

The oxidoreductase Trx-1 (thioredoxin 1) is highly conserved and found intra- and extra-cellularly in mammalian systems. There is increasing interest in its capacity to regulate immune function based on observations of altered distribution and expression during ageing and disease. We have investigated previously whether extracellular T-cell or peripheral blood mononuclear cell Trx-1 levels serve as a robust marker of ageing. In a preliminary study of healthy older adults compared with younger adults, we showed that there was a significant, but weak, relationship with age. Interestingly, patients with rheumatoid arthritis and cancer have been described by others to secrete or express greater surface Trx-1 than predicted. It is interesting to speculate whether a decline in Trx-1 during ageing protects against such conditions, but correspondingly increases risk of disease associated with Trx-1 depletion such as cardiovascular disease. These hypotheses are being explored in the MARK-AGE study, and preliminary findings confirm an inverse correlation of surface Trx-1 with age. We review recent concepts around the role of Trx-1 and its partners in T-cell function on the cell surface and as an extracellular regulator of redox state in a secreted form. Further studies on the redox state and binding partners of surface and secreted Trx-1 in larger patient datasets are needed to improve our understanding of why Trx-1 is important for lifespan and immune function.
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http://dx.doi.org/10.1042/BST20140162DOI Listing
August 2014

Healthy ageing and depletion of intracellular glutathione influences T cell membrane thioredoxin-1 levels and cytokine secretion.

Chem Cent J 2013 Sep 5;7(1):150. Epub 2013 Sep 5.

Life and Health Sciences, Aston University, Aston Triangle Birmingham B4 7ET, UK.

Background: During ageing an altered redox balance has been observed in both intracellular and extracellular compartments, primarily due to glutathione depletion and metabolic stress. Maintaining redox homeostasis is important for controlling proliferation and apoptosis in response to specific stimuli for a variety of cells. For T cells, the ability to generate specific response to antigen is dependent on the oxidation state of cell surface and cytoplasmic protein-thiols. Intracellular thiols are maintained in their reduced state by a network of redox regulating peptides, proteins and enzymes such as glutathione, thioredoxins and thioredoxin reductase. Here we have investigated whether any relationship exists between age and secreted or cell surface thioredoxin-1, intracellular glutathione concentration and T cell surface thioredoxin 1 (Trx-1) and how this is related to interleukin (IL)-2 production.

Results: Healthy older adults have reduced lymphocyte surface expression and lower circulating plasma Trx-1 concentrations. Using buthionine sulfoximine to deplete intracellular glutathione in Jurkat T cells we show that cell surface Trx-1 is lowered, secretion of Trx-1 is decreased and the response to the lectin phytohaemagglutinin measured as IL-2 production is also affected. These effects are recapitulated by another glutathione depleting agent, diethylmaleate.

Conclusion: Together these data suggest that a relationship exists between the intracellular redox compartment and Trx-1 proteins. Loss of lymphocyte surface Trx-1 may be a useful biomarker of healthy ageing.
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http://dx.doi.org/10.1186/1752-153X-7-150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3766689PMC
September 2013

Terminal galactose residues on transferrin are increased in midlife adults compared to young adults.

Proteomics 2012 Nov 12;12(21):3147-53. Epub 2012 Oct 12.

Life and Health Sciences, Aston University, Birmingham, UK.

Humans undergo biological ageing at different rates. This associates with functional decline in a number of physiological systems and increasing incidence of age-related pathologies. The discovery of robust biomarkers of ageing could be used to identify early divergence from a path of healthy ageing towards age-related disease. In the present study, we undertook proteomic analysis of plasma from healthy young men (mean age = 21.4 ± 1.5 years) and healthy midlife men (mean age = 57.0 ± 1.6 years). We identified 12 spots including transferrin, complement C3b and transthyretin that differed in abundance between the age groups. Transferrin spots showed an acidic pI shift in older males. Sandwich ELISAs were used to investigate the changes further. C3b levels were below the level of detection by ELISA and plasma concentrations of total transferrin or transthyretin were not different between the age groups studied here. However, analysis of transferrin N-glycan structures showed an increase in terminal galactose residues in older men, suggesting that the loss of terminal N-acetyl neuraminic acid residues contributes to the more acid pI of transferrin spots observed with age. Terminal galactosylation of transferrin may be a biomarker of healthy ageing and is now under investigation in the MARK-AGE study.
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http://dx.doi.org/10.1002/pmic.201100506DOI Listing
November 2012

Palmitate promotes monocyte atherogenicity via de novo ceramide synthesis.

Free Radic Biol Med 2012 Aug 26;53(4):796-806. Epub 2012 May 26.

School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.

Elevated plasma free fatty acids (FAs) are associated with increased risk of cardiovascular disease. This study investigates the effects of the saturated FA palmitate and unsaturated FA oleate on monocyte phenotype and function. Incubation of human U937 and THP-1 monocytes with palmitate for 24h increased cell surface expression of integrin CD11b and scavenger receptor CD36 in a concentration-dependent manner with some decrease in mitochondrial reducing capacity at high concentration (300 μM). Monocytes incubated with palmitate, but not oleate, showed increased uptake of oxidized LDL and increased adhesion to rat aortic endothelium, particularly at bifurcations. The palmitate-induced increase in CD11b and CD36 expression was associated with increased cellular C16 ceramide and sphingomyelin, loss of reduced glutathione, and increased reactive oxygen species (ROS). Increased monocyte surface CD11b and CD36 was inhibited by fumonisin B1, an inhibitor of de novo ceramide synthesis, but not by the superoxide dismutase mimetic MnTBap. In contrast, MnTBap prevented the mitochondrial ROS increase and metabolic inhibition due to 300μM palmitate. This study demonstrates that in viable monocytes, palmitate but not oleate increases expression of surface CD11b and CD36. Palmitate increases monocyte adhesion to the aortic wall and promotes uptake of oxidized LDL and this involves de novo ceramide synthesis.
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http://dx.doi.org/10.1016/j.freeradbiomed.2012.05.026DOI Listing
August 2012

Free radicals and redox signalling in T-cells during chronic inflammation and ageing.

Biochem Soc Trans 2011 Oct;39(5):1273-8

School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.

During chronic inflammation and ageing, the increase in oxidative stress in both intracellular and extracellular compartments is likely to influence local cell functions. Redox changes alter the T-cell proteome in a quantitative and qualitative manner, and post-translational modifications to surface and cytoplasmic proteins by increased reactive species can influence T-cell function. Previously, we have shown that RA (rheumatoid arthritis) T-cells exhibit reduced ROS (reactive oxygen species) production in response to extracellular stimulation compared with age-matched controls, and basal ROS levels [measured as DCF (2',7'-dichlorofluorescein) fluorescence] are lower in RA T-cells. In contrast, exposing T-cells in vitro to different extracellular redox environments modulates intracellular signalling and enhances cytokine secretion. Together, these data suggest that a complex relationship exists between intra- and extra-cellular redox compartments which contribute to the T-cell phenotype.
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http://dx.doi.org/10.1042/BST0391273DOI Listing
October 2011

Proteomic analysis of the anti-inflammatory action of minocycline.

Proteomics 2011 Jan 6;11(1):42-51. Epub 2010 Dec 6.

Life and Health Sciences, Aston University, Aston Triangle, Birmingham, UK.

Minocycline possesses anti-inflammatory properties independently of its antibiotic activity although the underlying molecular mechanisms are unclear. Lipopolysaccharide (LPS)-induced cytokines and pro-inflammatory protein expression are reduced by minocycline in cultured macrophages. Here, we tested a range of clinically important tetracycline compounds (oxytetracycline, doxycycline, minocycline and tigecycline) and showed that they all inhibited LPS-induced nitric oxide production. We made the novel finding that tigecycline inhibited LPS-induced nitric oxide production to a greater extent than the other tetracycline compounds tested. To identify potential targets for minocycline, we assessed alterations in the macrophage proteome induced by LPS in the presence or absence of a minocycline pre-treatment using 2-DE and nanoLC-MS. We found a number of proteins, mainly involved in cellular metabolism (ATP synthase β-subunit and aldose reductase) or stress response (heat shock proteins), which were altered in expression in response to LPS, some of which were restored, at least in part, by minocycline. This is the first study to document proteomic changes induced by minocycline. The observation that minocycline inhibits some, but not all, of the LPS-induced proteomic changes shows that minocycline specifically affects some signalling pathways and does not completely inhibit macrophage activation.
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http://dx.doi.org/10.1002/pmic.201000273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3430857PMC
January 2011

Activation of the neutrophil respiratory burst by plasma from periodontitis patients is mediated by pro-inflammatory cytokines.

J Clin Periodontol 2011 Jan 21;38(1):1-7. Epub 2010 Oct 21.

School of Life and Health Sciences, Aston University, Birmingham, UK.

Aim: To determine the effect of periodontitis patients' plasma on the neutrophil oxidative burst and the role of albumin, immunoglobulins (Igs) and cytokines.

Materials And Methods: Plasma was collected from chronic periodontitis patients (n=11) and periodontally healthy controls (n=11) and used with/without depletion of albumin and Ig or antibody neutralization of IL-8, GM-CSF or IFN-α to prime/stimulate peripheral blood neutrophils, isolated from healthy volunteers. The respiratory burst was measured by lucigenin-dependent chemiluminescence. Plasma cytokine levels were determined by ELISA.

Results: Plasmas from patients were significantly more effective in both directly stimulating neutrophil superoxide production and priming for subsequent formyl-met-leu-phe (fMLP)-stimulated superoxide production than plasmas from healthy controls (p<0.05). This difference was maintained after depletion of albumin and Ig. Plasma from patients contained higher mean levels of IL-8, GM-CSF and IFN-α. Individual neutralizing antibodies against IL-8, GM-CSF or IFN-α inhibited the direct stimulatory effect of patients' plasma, whereas the ability to prime for fMLP-stimulated superoxide production was only inhibited by neutralization of IFN-α. The stimulating and priming effects of control plasma were unaffected by antibody neutralization.

Conclusions: This study demonstrates that plasma cytokines may have a role in inducing the hyperactive (IL-8, GM-CSF, IFN-α) and hyper-reactive (IFN-α) neutrophil phenotype seen in periodontitis patients.
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http://dx.doi.org/10.1111/j.1600-051X.2010.01628.xDOI Listing
January 2011