Analysis of nerve growth factor (NGF) gene methylation in patients with schizophrenia

Abstract

According to the neurotrophin hypothesis, schizophrenia can be caused by neurotrophic factors. One of these neurotrophic factors is the nerve growth factor (NGF), which has a critical role in cognitive functions. The present study aimed to investigate the NGF gene promoter methylation pattern in patients with schizophrenia and healthy individuals. Participants included patients with schizophrenia (84 males and 38 females) and healthy controls (96 males and 48 females). Blood samples were collected from all of the subjects in treated tubes for DNA extraction. The determination of the methylation pattern of the NGF gene CpG island-2 was based on the principle that bisulfite treatment of DNA results in the conversion of unmethylated bases of cytosine into uracil bases. The results showed no significant difference in the DNA methylation status for the NGF gene CpG island-2 in patients with schizophrenia and healthy individuals. Also, no significant difference was observed in the methylated and unmethylated status for the NGF gene CpG island-2 region when patients were compared with clinical parameters. In addition, relative NGF mRNA expression was significantly lower in patients with schizophrenia compared to healthy controls. However, no significant difference was observed in methylated and unmethylated status in the NGF mRNA expression. Although clinical evidence indicates a decrease in serum NGF levels in patients with schizophrenia, in the present study, there was no difference in the methylation status of the NGF gene promoter CpG island-2 between patients with schizophrenia and healthy individuals.