British Journal of Nutrition

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British Journal of Nutrition (2010), 103:1771-1777 Cambridge University Press
Copyright © The Authors 2010
doi:10.1017/S000711451000005X

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Nutritional Immunology

Effects of epigallocatechin gallate on regulatory T cell number and function in obese v. lean volunteers


Jung-Mi Yuna1, Ishwarlal Jialala1 and Sridevi Devaraja1 c1

a1 Department of Pathology and Laboratory Medicine, University of California, Davis, Medical Center, Sacramento, CA, USA
Article author query
yun jm [PubMed]  [Google Scholar]
jialal i [PubMed]  [Google Scholar]
devaraj s [PubMed]  [Google Scholar]

Abstract

Obesity predisposes to an increased incidence of diabetes and CVD. Also, obesity is a pro-inflammatory state. Regulatory T cells (Tregs) are essential negative regulators of inflammation and are down-regulated in pro-inflammatory states. Animal models of obesity are associated with decreased Tregs. The dietary modulation of Tregs could be used as a therapeutic strategy to control inflammation. Epigallocatechin gallate (EGCG) is a potent anti-inflammatory agent and an active ingredient of green tea and is suggested to have a role as a preventive agent in obesity, diabetes and CVD. The role of EGCG in the modulation of Tregs has, however, not been studied. Thus, the aim of the present study was to determine the effect of EGCG on the number and function of Tregs in obese and lean human subjects in vitro, and to delineate its specific regulation mechanisms. Tregs were isolated from normal-weight and obese subjects. Tregs were cultured in the absence or presence of EGCG (20 μm) for 24 h. Foxp3-expressing Tregs were enumerated using flow cytometry. Histone deacetylase (HDAC) activity and nuclear NF-κBp65 level were measured by ELISA and Western blots. Obese subjects had lower Tregs and IL-10 production than lean subjects. EGCG treatment significantly enhanced the number of Foxp3-expressing Tregs and IL-10 production in vitro (P < 0·05) in both groups. Also, EGCG decreased NF-κB activity and increased HDAC activity and HDAC-2 expression in Tregs (P < 0·05) in both groups. Thus, in part, EGCG enhances the functionality of Tregs, i.e. IL-10 production and number by suppressing the NF-κB signalling pathway via inducing epigenetic changes.

(Received August 12 2009)

(Revised November 09 2009)

(Accepted December 17 2009)

(Online publication February 23 2010)

Key Words:Regulatory T cells; Inflammation; Green tea; Epigenetics

Correspondence:

c1 Corresponding author: Dr Sridevi Devaraj, fax +1 91 67346593, email sridevi.devaraj@ucdmc.ucdavis.edu

Footnotes

Abbreviations: APC, allophycocyanin; EGCG, epigallocatechin gallate; Foxp3, forkhead family transcription factor; HDAC, histone deacetylases; PE, phycoerythrin; Tregs, regulatory T cells


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