BDNF promoter I methylation correlates between post-mortem human peripheral and brain tissues

Several psychiatric disorders have been associated with CpG methylation changes in CG rich promoters of the brain-derived neurotrophic factor (BDNF) mainly by extracting DNA from peripheral blood cells. Whether changes in peripheral DNA methylation can be used as a proxy for brain-specific alterations remains an open question. In this study we aimed to compare DNA methylation levels in BDNF promoter regions in human blood cells, muscle and brain regions using bisulfite-pyrosequencing. We found a significant correlation between the levels of BDNF promoter I methylation measured in quadriceps and vPFC tissues extracted from the same individuals (n=98, Pearson, r=0.48, p=4.5 x 10(-7)). In the hippocampus, BDNF promoter I and IV methylation levels were strongly correlated (Pearson, n=37, r=0.74, p =1.4 x 10(-7)). We found evidence for sex-dependent effect on BDNF promoter methylation levels in the various tissues and blood samples. Taken together, these data indicate a strong intra-individual correlation between peripheral and brain tissue. They also suggest that sex determines methylation patterns in BDNF promoter region across different types of tissue, including muscle, brain, and blood. (C) 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.