Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects
<p>Abstract</p> <p>Background</p> <p>Oxidative stress may lead to an increased level of unrepaired cellular DNA damage, which is discussed as one risk for tumor initiation. Mismatch repair (MMR) enzymes act as proofreading complexes that maintain the genomic integrity a...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2012-10-01
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| Series: | Clinical Epigenetics |
| Subjects: | |
| Online Access: | http://www.clinicalepigeneticsjournal.com/content/4/1/19 |
| _version_ | 1818565235857948672 |
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| author | Switzeny Olivier J Müllner Elisabeth Wagner Karl-Heinz Brath Helmut Aumüller Eva Haslberger Alexander G |
| author_facet | Switzeny Olivier J Müllner Elisabeth Wagner Karl-Heinz Brath Helmut Aumüller Eva Haslberger Alexander G |
| author_sort | Switzeny Olivier J |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Oxidative stress may lead to an increased level of unrepaired cellular DNA damage, which is discussed as one risk for tumor initiation. Mismatch repair (MMR) enzymes act as proofreading complexes that maintain the genomic integrity and MMR-deficient cells show an increased mutation rate. One important gene in the MMR complex is the MutL homolog 1 (<it>MLH1</it>) gene. Since a diet rich in antioxidants has the potential to counteract harmful effects by reactive oxygen species (ROS), we investigated the impact of an antioxidant, folate, and vitamin rich diet on the epigenetic pattern of <it>MLH1</it>. These effects were analyzed in individuals with non-insulin depended diabetes mellitus type 2 (NIDDM2) and impaired fasting glucose (IFG).</p> <p>Methods</p> <p>In this post-hoc analysis of a randomized trial we analyzed DNA methylation of <it>MLH1</it>, <it>MSH2</it>, and <it>MGMT</it> at baseline and after 8 weeks of intervention, consisting of 300 g vegetables and 25 ml plant oil rich in polyunsaturated fatty acids per day. DNA methylation was quantified using combined bisulfite restriction enzyme analysis (COBRA) and pyrosequencing. <it>MLH1</it> and <it>DNMT1</it> mRNA expression were investigated by qRT-PCR. DNA damage was assessed by COMET assay. Student’s two-tailed paired t test and one-way ANOVA with Scheffé corrected Post hoc test was used to determine significant methylation and expression differences. Two-tailed Pearson test was used to determine correlations between methylation level, gene expression, and DNA strand break amount.</p> <p>Results</p> <p>The intervention resulted in significantly higher CpG methylation in two particular <it>MLH1</it> promoter regions and the <it>MGMT</it> promoter. DNA strand breaks and methylation levels correlated significantly. The expression of <it>MLH1</it>, <it>DNMT1</it>, and the promoter methylation of <it>MSH2</it> remained stable. CpG methylation levels and gene expression did not correlate.</p> <p>Conclusion</p> <p>This vitamin and antioxidant rich diet affected the CpG methylation of <it>MLH1</it>. The higher methylation might be a result of the ROS scavenging antioxidant rich diet, leading to lower activity of DNA demethylating enzymes. Our results suggest the hypothesis of CpG demethylation via DNA repair enzymes under these circumstances. NIDDM2 and IFG patients benefit from this simple dietary intervention involving epigenetic and DNA repair mechanisms.</p> |
| first_indexed | 2024-12-14T01:38:39Z |
| format | Article |
| id | doaj.art-ca62c1fbcaf2409a9e93190bfeaf55e0 |
| institution | Directory Open Access Journal |
| issn | 1868-7083 |
| language | English |
| last_indexed | 2024-12-14T01:38:39Z |
| publishDate | 2012-10-01 |
| publisher | BMC |
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| series | Clinical Epigenetics |
| spelling | doaj.art-ca62c1fbcaf2409a9e93190bfeaf55e02022-12-21T23:21:48ZengBMCClinical Epigenetics1868-70832012-10-01411910.1186/1868-7083-4-19Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjectsSwitzeny Olivier JMüllner ElisabethWagner Karl-HeinzBrath HelmutAumüller EvaHaslberger Alexander G<p>Abstract</p> <p>Background</p> <p>Oxidative stress may lead to an increased level of unrepaired cellular DNA damage, which is discussed as one risk for tumor initiation. Mismatch repair (MMR) enzymes act as proofreading complexes that maintain the genomic integrity and MMR-deficient cells show an increased mutation rate. One important gene in the MMR complex is the MutL homolog 1 (<it>MLH1</it>) gene. Since a diet rich in antioxidants has the potential to counteract harmful effects by reactive oxygen species (ROS), we investigated the impact of an antioxidant, folate, and vitamin rich diet on the epigenetic pattern of <it>MLH1</it>. These effects were analyzed in individuals with non-insulin depended diabetes mellitus type 2 (NIDDM2) and impaired fasting glucose (IFG).</p> <p>Methods</p> <p>In this post-hoc analysis of a randomized trial we analyzed DNA methylation of <it>MLH1</it>, <it>MSH2</it>, and <it>MGMT</it> at baseline and after 8 weeks of intervention, consisting of 300 g vegetables and 25 ml plant oil rich in polyunsaturated fatty acids per day. DNA methylation was quantified using combined bisulfite restriction enzyme analysis (COBRA) and pyrosequencing. <it>MLH1</it> and <it>DNMT1</it> mRNA expression were investigated by qRT-PCR. DNA damage was assessed by COMET assay. Student’s two-tailed paired t test and one-way ANOVA with Scheffé corrected Post hoc test was used to determine significant methylation and expression differences. Two-tailed Pearson test was used to determine correlations between methylation level, gene expression, and DNA strand break amount.</p> <p>Results</p> <p>The intervention resulted in significantly higher CpG methylation in two particular <it>MLH1</it> promoter regions and the <it>MGMT</it> promoter. DNA strand breaks and methylation levels correlated significantly. The expression of <it>MLH1</it>, <it>DNMT1</it>, and the promoter methylation of <it>MSH2</it> remained stable. CpG methylation levels and gene expression did not correlate.</p> <p>Conclusion</p> <p>This vitamin and antioxidant rich diet affected the CpG methylation of <it>MLH1</it>. The higher methylation might be a result of the ROS scavenging antioxidant rich diet, leading to lower activity of DNA demethylating enzymes. Our results suggest the hypothesis of CpG demethylation via DNA repair enzymes under these circumstances. NIDDM2 and IFG patients benefit from this simple dietary intervention involving epigenetic and DNA repair mechanisms.</p>http://www.clinicalepigeneticsjournal.com/content/4/1/19MLH1ROSDNA methylationDemethylationNutritional interventionDiabetesAntioxidantPyrosequencing |
| spellingShingle | Switzeny Olivier J Müllner Elisabeth Wagner Karl-Heinz Brath Helmut Aumüller Eva Haslberger Alexander G Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects Clinical Epigenetics MLH1 ROS DNA methylation Demethylation Nutritional intervention Diabetes Antioxidant Pyrosequencing |
| title | Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects |
| title_full | Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects |
| title_fullStr | Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects |
| title_full_unstemmed | Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects |
| title_short | Vitamin and antioxidant rich diet increases <it>MLH1</it> promoter DNA methylation in DMT2 subjects |
| title_sort | vitamin and antioxidant rich diet increases it mlh1 it promoter dna methylation in dmt2 subjects |
| topic | MLH1 ROS DNA methylation Demethylation Nutritional intervention Diabetes Antioxidant Pyrosequencing |
| url | http://www.clinicalepigeneticsjournal.com/content/4/1/19 |
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