Alternative Splicing, Methylation State, and Expression Profile of Tropomyosin-Related Kinase B in the Frontal Cortex of Suicide Completers

This study tested the hypothesis that tropomyosin-related kinase B expression is downregulated in suicide completers & that this downregulation is mediated by an epigenetic process. 39 French-Canadian men underwent screening using the HG-U133 plus 2 microarray chip. 9 frontal cortical regions & the cerebellum were assessed using a microarray screening approach for extreme expression differences across subjects & a conventional screening approach. 10 of 28 suicide completers demonstrated significant decreases in different probe sets specific to tropomyosin-related kinase B in Brodmann areas 8 & 9. These findings were generalizable to other frontal regions but not to the cerebellum. This reduction was associated with the methylation state of the promoter region. (74 refs.) JA