RESUMEN
BACKGROUND: Serotonin 3A receptor (5-HT3A R) is associated at the genetic and epigenetic levels with a variety of psychiatric disorders and interacts with early-life stress such as childhood maltreatment. We studied the impact of childhood maltreatment on the methylation status of the 5-HT3A R and its association with clinical severity outcomes in relation with a functional genetic polymorphism. METHODS: Clinical severity indexes of 346 bipolar, borderline personality, and adult attention deficit hyperactivity disorders patients were tested for association with the DNA methylation status of eight 5-HT3A R gene CpGs. Relationship between the functional variant rs1062613 (C > T) and methylation status on severity of the disorders were also assessed. RESULTS: Childhood maltreatment was associated with higher severity of the disease (higher number of mood episodes, history of suicide attempts, hospitalization, and younger age at onset) across disorders and within each individual disorder. This effect was mediated by two 5-HT3A R CpGs. Compared to T allele carriers, CC carriers had higher methylation status at one CpG located 1 bp upstream of this variant. CONCLUSIONS: This study shows that epigenetic modification of the 5-HT3A R is involved in the mechanism underlying the relationship between maltreatment in childhood and the severity of several psychiatric disorders in adulthood.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/genética , Trastorno Bipolar/genética , Trastorno de Personalidad Limítrofe/genética , Maltrato a los Niños/psicología , Metilación de ADN , Receptores de Serotonina 5-HT3/genética , Adulto , Trastorno por Déficit de Atención con Hiperactividad/psicología , Trastorno Bipolar/psicología , Trastorno de Personalidad Limítrofe/psicología , Niño , Femenino , Humanos , Masculino , Polimorfismo Genético/genética , Índice de Severidad de la EnfermedadRESUMEN
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 × 10(-7)). In the hippocampus, BDNF promoter I and IV methylation levels were strongly correlated (Pearson, n = 37, r = 0.74, p = 1.4 × 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.