The role of BDNF exon I region methylation in the treatment of depression with sertraline and its clinical diagnostic value

Brain-derived neurotrophic factor (BDNF) epigenomic modifications and brain-related phenotypes in humans: A systematic review

Epigenomic modifications of the brain-derived neurotrophic factor (BDNF) gene have been postulated to underlie the pathogenesis of neurodevelopmental, psychiatric, and neurological conditions. This systematic review summarizes current evidence investigating the association of BDNF epigenomic modifications (DNA methylation, non-coding RNA, histone modifications) with brain-related phenotypes in humans. A novel contribution is our creation of an open access web-based application, the BDNF DNA Methylation Map, to interactively visualize specific positions of CpG sites investigated across all studies for which relevant data were available. Our literature search of four databases through September 27, 2021 returned 1701 articles, of which 153 met inclusion criteria. Our review revealed exceptional heterogeneity in methodological approaches, hindering the identification of clear patterns of robust and/or replicated results. We summarize key findings and provide recommendations for future epigenomic research. The existing literature appears to remain in its infancy and requires additional rigorous research to fulfill its potential to explain BDNF-linked risk for brain-related conditions and improve our understanding of the molecular mechanisms underlying their pathogenesis.

BDNF as a Mediator of Antidepressant Response: Recent Advances and Lifestyle Interactions

Conventional antidepressants are widely employed in several psychiatric and neurologic disorders, yet the mechanisms underlying their delayed and partial therapeutic effects are only gradually being understood. This narrative review provides an up-to-date overview of the interplay between antidepressant treatment and Brain-Derived Neurotrophic Factor (BDNF) signaling. In addition, the impact of nutritional, environmental and physiological factors on BDNF and the antidepressant response is outlined. This review underlines the necessity to include information on lifestyle choices in testing and developing antidepressant treatments in the future.

Methylation of BDNF and SLC6A4 Gene Promoters in Brazilian Patients With Temporal Lobe Epilepsy Presenting or Not Psychiatric Comorbidities

The relationship between epilepsy and psychiatric comorbidities has been recognized for centuries, but its pathophysiological mechanisms are still misunderstood. It is biologically plausible that genetic or epigenetic variations in genes that codify important neurotransmitters involved in epilepsy as well as in psychiatric disorders may influence the development of the latter in patients with epilepsy. However, this possibility remains poorly investigated. The aim of this study was to evaluate the methylation profile of the BDNF and SLC6A4, two genes importantly involved in neuroplasticity, in patients with temporal lobe epilepsy (TLE) regarding the development or not of psychiatric comorbidities. One hundred and thirty-nine patients with TLE, 90 females and 45 males, were included in the study. The mean age of patients was 44.0 (+12.0) years, and mean duration of epilepsy was 25.7 (+13.3) years. The Structured Clinical Interview for DSM-IV shows that 83 patients (59.7%) had neuropsychiatric disorders and 56 (40.3%) showed no psychiatric comorbidity. Mood disorders were the most common psychiatric disorder observed, being present in 64 (46.0%) of all 139 patients. Thirty-three (23.7%) patients showed anxiety disorders, 10 (7.2%) patients showed history of psychosis and 8 (5.8%) patients showed history of alcohol//drug abuse. Considering all 139 patients, 18 (12.9%) demonstrated methylation of the promoter region of both BDNF and SLC6A4 genes. A significant decreased methylation profile was observed only in TLE patients with mood disorders when compared with TLE patients without a history of mood disorders (O.R. = 3.45; 95% C.I. = 1.08–11.11; p = 0.04). A sub-analysis showed that TLE patients with major depressive disorder mostly account for this result (O.R. = 7.20; 95% C.I. = 1.01–56.16; p = 0.042). A logistic regression analysis showed that the independent factors associated with a history of depression in our TLE patients was female sex (O.R. = 2.30; 95% C.I. = 1.02–5.18; p = 0.044), not controlled seizures (O.R. = 2.51; 95% C.I. = 1.16–5.41; p = 0.019) and decreased methylation in BDNF and SLC6A4 genes (O.R. = 5.32; 95% C.I. = 1.14–25.00; p = 0.033). Our results suggest that BDNF or SLC6A4 genes profile methylation is independently associated with depressive disorders in patients with epilepsy. Further studies are necessary to clarify these matters.

The role of BDNF exon I region methylation in the treatment of depression with sertraline and its clinical diagnostic value

Background

Brain‐derived neurotrophic factor (BDNF) is considered to be one of the best candidate genes for depression. However, whether sertraline treatment affects the methylation level of this gene remains unknown.

Methods

Fifty‐three patients with depression and 51 healthy controls were included in the study. The methylation level of BDNF exon I was determined in blood samples from these subjects. The Hamilton Depression Scale was used to evaluate the depression status of patients. Single nucleotide polymorphism detection was used for genotyping, and a receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the methylation level of this locus in patients with depression.

Results

There was a significant difference in the methylation level of BDNF exon I between the control and depression groups. No effect of sertraline monotherapy on BDNF methylation was found in subjects with depression. Moreover, no interaction was found between BDNF genotype and the per cent methylation of BDNF exon I. However, methylation at this site was positively correlated with diurnal variation and retardation scores. Blood homocysteine concentrations were significantly reduced by sertraline treatment. No influence of genotype on serum BDNF concentration was found in subjects with depression. The ROC curve showed that methylation of BDNF exon I may be used to distinguish patients from healthy people, to a certain extent.

Conclusion

Methylation of BDNF exon I may be used as a biomarker of depression and may be a therapeutic target for previously untreated depression.