British Journal of Nutrition

Full Papers

Gene Expression

Epigenetic regulation of human buccal mucosa mitochondrial superoxide dismutase gene expression by diet

Roman Thalera1, Heidrun Karlica2a3, Petra Rusta1 and Alexander G. Haslbergera1 c1

a1 Department of Nutritional Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria

a2 Ludwig Boltzmann Institute for Leukaemia Research, Hanusch Krankenhaus, Vienna, Austria

a3 Hanuschkrankenhaus der Wiener Gebietskrankenkasse, Heinrich Collinstraße 30, A-1140 Vienna, Austria

Abstract

The impact of nutrition on the epigenetic machinery has increasingly attracted interest. The aim of the present study was to demonstrate the effects of various diets on methylation and gene expression. The antioxidative enzyme mitochondrial superoxide dismutase (MnSOD) was chosen as the model system because epigenetic regulation has been previously shown in cell lines for this gene. Promoter methylation and gene expression of MnSOD in buccal swabs from three sample groups were analysed. The three groups included: (1) forty vegetarians (aged 20–30 years); (2) age-matched omnivores; (3) elderly omnivores (aged>85 years). A 3-fold increase in the expression of the MnSOD gene was associated with decreased CpG methylation of the analysed promoter region in the vegetarian group compared with the age-matched omnivores group. Expression and promoter methylation of the MnSOD gene in elderly omnivores showed no significant differences compared with younger omnivores. In accordance with previous findings in various tissues, DNA global methylation was found to be significantly higher (30 %) in buccal swabs of younger subjects (independent of the diet), than in those of elderly omnivores. In the control experiment which was designed to verify the findings of the human buccal swab studies, the Caco-2 cell line was treated with zebularine. Results of the control study showed a 6-fold increase of MnSOD expression, an approximately 40 % decreased methylation of specified CpG in the MnSOD promoter and a 50 % reduction of global DNA methylation. These results indicate that diet affects the epigenetic regulation of human MnSOD.

(Received October 30 2007)

(Revised June 24 2008)

(Accepted June 26 2008)

(Online publication August 07 2008)

Correspondence:

c1 Corresponding author: Dr Alexander G. Haslberger, fax +43 1 8795896, email alexander.haslberger@univie.ac.at

Footnotes

Abbreviations: DNMT, DNA methyltransferase; G6PD, glucose-6-phosphate dehydrogenase; MnSOD, mitochondrial superoxide dismutase; SAH, S-adenosylhomocysteine; SAM, S-adenosylmethionine; TA, telomerase activity

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