Effect of (Poly)phenols on cytokine release and glutathione metabolism in Jurkat T-Lymphocytes.


Richardson, S (2016) Effect of (Poly)phenols on cytokine release and glutathione metabolism in Jurkat T-Lymphocytes. PhD thesis, University of Liverpool.

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Abstract

Chronic inflammation and increases in oxidative stress are observed in normal ageing and age related diseases, these are characterised by increases in aberrant NF-κB activation, expression of inflammatory genes and circulating cytokines. Dietary polyphenols found in fruits and vegetables, have been examined for potential antioxidant and anti-inflammatory effects in in vitro/vivo studies. 29 (poly)phenols were screened for their anti-inflammatory effects in Jurkat T-cells following 48h treatment. At 1μM, a physiologically relevant dose, resveratrol (RES) decreased IL2 release by 42% ± 7% and IL8 by 32% ± 8% compared with DMSO treated control (p<0.05). Cells were also stimulated with PMA/PHA to induce cytokine release at the 24h time-point, 1μM isorhamnetin (ISO) reduced cytokine release, IL2 by 50% ± 4%, IL8 by 58% ± 6% and TNFα by 63% ± 7%, and curcumin (CUR) reduced IL2 by 43% ± 14%, IL8 by 30% ± 7% and TNFα by 22% ± 5 compared with PMA/PHA treated control (p<0.05). These 3 compounds; CUR, ISO and RES, were investigated further using a proteomic approach. Several proteins were modified in the glutathione metabolism pathway with all treatments significantly (sig.) increasing glutathione reductase (GSR), an enzyme which converts oxidized to reduced glutathione. CUR increased GSR by 1.2 fold, ISO 1.2 fold and RES 1.1 fold (p<0.003). ISO also caused sig. increases in other redox related proteins thioredoxin and peroxiredoxins. These data were validated with sig. increases in GSR gene expression with CUR and ISO at 24h, along with sig. increases in Nrf2 activation, CUR (1.5 fold) and ISO (1.9 fold). These modulations to inflammatory and redox markers in the Jurkat cell model were replicated in another cell line, THP-1 monocytes. A sig. reduction in cytokine release was observed with 30µM ISO for both IL8 and TNFα compared with the DMSO, correlating with the reduction observed in the Jurkat cells. Nrf2 was also sig. activated between 3 and 48h, however no sig. effect on the expression of GSR was observed. This suggests that ISO may have similar effects on inflammation but differed in terms of redox related proteins between the two cell types. CUR, ISO and RES sig. lowered cytokine release in both unstimulated and stimulated T-cells, and proteomics identified sig. increases in GSR. For CUR and ISO this increase was validated using western blot and qPCR analysis, with sig. increases in Nrf2 activation bring observed. The reduction in cytokine release was replicated in THP-1 following ISO treatment, along with increases in Nrf2 activation, but no changes in glutathione proteins were observed. These data support the potential use of these compounds in enhancing cellular antioxidant potential and the use of the compounds as part of a healthy ageing diet.

Item Type: Thesis (PhD)
Divisions: Faculty of Health and Life Sciences
Depositing User: Symplectic Admin
Date Deposited: 15 Dec 2016 14:47
Last Modified: 19 Jan 2023 07:32
DOI: 10.17638/03002632
Supervisors:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3002632
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