Background: There is a positive association between solar UVexposure and micronucleus frequency in peripheral blood lymphocytes (PBL) andthis association may be stronger when serum vitamin D (25(OH)D) levels areinsufficient (<50 nmol/L). Micronucleus formation can result from globalhypomethylation of DNA repeat sequences. The aim of this analysis was toevaluate the relationship between solar UV exposure and methylation pattern inLINE-1 repetitive elements in PBL DNA and to see if serum 25(OH)D levels modifyit.
Method: Personal solar UV exposure was estimated from hours of outdoor exposure over 6 weeks recalled at the time of blood collection in 208 male and female participants living in South Australia. Methylation in LINE-1 repetitive elements was assessed in PBL using pyrosequencing.
Results: Methylation in LINE-1 decreased with increasing solar UV exposure (% decrease = 0.5% per doubling of sUV; 95%CI: −0.7 to −0.2 pvalue = 0.00003). Although there was no correlation between LINE-1 methylation and micronucleus frequency, there was a 4.3% increase (95%CI: 0.6–8.1 p-value = 0.02) in nucleoplasmic bridges and a 4.3% increase in necrosis (CI: 1.9–6.8 p-value = 0.0005) for every 1% increase in LINE-1 methylation. Serum 25(OH)D was not associated with DNA methylation; or did it modify the association of solar UV with DNA methylation.
Conclusion: Exposure to solar UV radiation may reduce DNA methylation in circulating lymphocytes. This association does not appear to be influenced or mediated by vitamin D status.
|Number of pages||5|
|Journal||Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis|
|Publication status||Published - Jul 2014|
- Solar UV exposure
- Vitamin D
- Global methylation
- LINE-1 repetitive elements
- DNA damage