[Influence of methylenetetrahydrofolate reductase gene polymorphisms on antidepressant response].

OBJECTIVE: To assess the influence of polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene on response to antidepressant treatment. METHODS: Two hundred and eight one Chinese Han patients have received single antidepressant drugs for at least 6 weeks, among whom 275 were followed up for 8 weeks. Hamilton depression scale 17 (HAMD-17) was used to evaluate the severity of depressive symptoms and therapeutic effects. Single nucleotide polymorphisms (SNPs) of the MTHFR gene were determined using gene chips. Associations of single loci and haplotypes with response to treatment were analyzed using an Unphased 3.0.13 software. RESULTS: No significant differences in gender, age, year of education, family history, episode times, and antidepressant agents were found between responders and non-responders (all P U+003E 0.05), while the baseline scores of HAMD-17 was significantly different(t=2.891, P=0.004). There was also no significant difference between age, years of education, family history, baseline scores of HAMD-17 and antidepressant agents between remitters and non-remitters (both P U+003E 0.05), while proportion of male patients was significantly higher in non-remission group than remission group (t=2.381, P=0.018), and episode times in non-remission group was significantly higher (t=-1.983, P=0.049). Single locus association analysis has found no significant association between SNPs rs1801131 and rs1801133 in the MTHFR gene with antidepressant response (P U+003E 0.05). On the other hand, haplotype A-C of MTHFR gene (rs1801131 and rs1801133) was significantly associated with antidepressant response in total group (U+03C7 2=11.39, P=0.0007), male subgroup (U+03C7 2=8.767, P=0.003) and serotonin noradrenaline reuptake inhibitors (SNRIs) subgroup (U+03C7 2=10.51, P=0.001). CONCLUSION: Particular haplotype of MTHFR gene may be related with antidepressant effect, in which the haplotype (rs1801131, rs1801133) A-C type may be associated with better antidepressant efficacy, particularly in males and patients receiving SNRIs drugs.

Influence of genetic polymorphisms involved in the hypothalamic-pituitary-adrenal axis and their interactions with environmental factors on antidepressant response.

AIMS: To investigate the role of genetic polymorphisms in candidate genes associated with the HPA axis and their interactions with environmental stressors in antidepressant response. METHODS: The remission of depressive symptoms after 8 weeks of antidepressant treatment was tested against 21 single nucleotide polymorphisms (SNPs) in five candidate genes associated with the HPA axis in a Chinese Han sample suffering from unipolar depression (n = 273). Any history of childhood trauma and recent negative life events were measured using the Childhood Trauma Questionnaire-Short Form (CTQ-SF) (n = 206) and the Life Event Scale (48 item, LES) (n = 207), respectively. Reporter gene assays were used to evaluate the possible effects of the most significant SNP on gene expression. RESULTS: A functional polymorphism at 3'UTR of the corticotropin-releasing hormone receptor 1 (CRHR1) gene (rs28364032) and three haplotypes containing it showed significant relationships with antidepressant remission. Further laboratory-based genomic studies showed that the G-to-A change of rs28364032 resulted in a 10-12% decrease in the intensity of luciferase activity. However, we failed to find association of environments and their interaction with HPA system-related genes with antidepressant remission. CONCLUSIONS: Our results support a definite role for CRHR1 in the pharmacogenetics of antidepressant drugs. This may contribute to interpatient differences in their responses to antidepressant drugs.

Kinase gene haplotypes and gene-gene interactions in the Ras-Raf-MAPK signaling pathway: association with antidepressant remission.

Signal transduction has been reported to be involved in antidepressant treatment outcomes; however, its mechanisms remain unclear. The aims of this study were to explore the associations between antidepressant remission and single nucleotide polymorphisms (SNPs), haplotypes, and gene-gene interactions in the Ras-Raf-MAPK intracellular signaling pathway. A total of 302 inpatients with major depressive disorder (DSM-IV Axis I) were assessed using the 17-item Hamilton Depression Rating Scale before and after 8 weeks of antidepressant treatment to determine the remission rate in the samples. Twenty-four SNPs at five kinase genes (Ras-Raf-MEK-ERK-RSK), which are a part of the Ras-Raf-MAPK signaling pathway, were identified to investigate a genetic association with antidepressant drug outcome. Correlations between 24 SNPs at the five kinase genes in the Ras-Raf-MAPK signaling pathway and antidepressant drug outcome were not found. The percentage of the CCAGA haplotype that RSK(2/3/4)-RSKL(1/2) gene loci SNPs constructed was markedly lower in the remitter group when compared with the nonremitter group in female depressed patients (P=0.04), whereas the proportion of AAAGGG haplotype that RSK(2/3/4)-RSKL(1/2) gene loci SNPs constructed in the remitter group was significantly greater than that in the nonremitter group in male patients (P=0.02). In addition, MEK1 (rs28730804) and RSK3 (rs2229712) in the Ras-Raf-MAPK signaling pathway showed a gene-gene interaction that affected antidepressant drug outcome in female depressed patients (P=0.041). Although this study did not find that SNPs at the five kinase genes in the Ras-Raf-MAPK signaling pathway are important markers for antidepressant outcome, certain haplotypes that SNPs at the RSK(2/3/4)-RSKL(1/2) gene constructed may be important markers for antidepressant drug efficacy. We observed a gene-gene interaction in this signaling pathway that influenced antidepressant efficacy in female depressed patients. Therefore, it is likely that in female depressed patients, different haplotypes and gene-gene interaction in the Ras-Raf-MAPK signaling pathway are involved in mediating the pharmacological action of an antidepressant, and eventually influence antidepressant efficacy.