PS45. SLC1A2 Promoter is Hypomethylated in Bipolar Disorder with Comorbid Addiction

s | 15 College of Medicine, 73 Inchon-ro, Seongbuk-gu, Seoul 136–705, Republic of Korea Tel: +82-2-920-6721, Fax: +82-2-929-7679, E-mail: [email protected] Abstract Previous studies have suggested an association between CACNA1C and susceptibility of bipolar disorder. In this study, we examined the association of CACNA1C variants with bipolar disorder in the Korean population. We selected 2 CACNA1C single nucleotide polymorphisms (SNPs), namely, rs723672 and rs1051375, based on their functions and minor allele frequencies described in previous studies. After purifying DNA from blood samples collected from 340 healthy controls and 287 patients with bipolar disorder, the genotypes of 2 CACNA1C SNPs were analyzed. Genotype frequencies of both rs723672 and rs1051375 SNPs were significantly different in patients and controls (p = 0.0462 and 1.732 × 10–14, respectively). Dominant, recessive, and allele models showed significant differences between patients and controls with respect to the rs1051375 SNP (p = 1.72 × 10–11, 4.17 × 10-10, and 4.95 × 10–16, respectively). Our results suggested that CACNA1C SNPs rs723672 and rs1051375 were associated with bipolar disorder in the Korean population. In addition, our results highlighted the importance of CACNA1C in determining susceptibility to bipolar disorder.Previous studies have suggested an association between CACNA1C and susceptibility of bipolar disorder. In this study, we examined the association of CACNA1C variants with bipolar disorder in the Korean population. We selected 2 CACNA1C single nucleotide polymorphisms (SNPs), namely, rs723672 and rs1051375, based on their functions and minor allele frequencies described in previous studies. After purifying DNA from blood samples collected from 340 healthy controls and 287 patients with bipolar disorder, the genotypes of 2 CACNA1C SNPs were analyzed. Genotype frequencies of both rs723672 and rs1051375 SNPs were significantly different in patients and controls (p = 0.0462 and 1.732 × 10–14, respectively). Dominant, recessive, and allele models showed significant differences between patients and controls with respect to the rs1051375 SNP (p = 1.72 × 10–11, 4.17 × 10-10, and 4.95 × 10–16, respectively). Our results suggested that CACNA1C SNPs rs723672 and rs1051375 were associated with bipolar disorder in the Korean population. In addition, our results highlighted the importance of CACNA1C in determining susceptibility to bipolar disorder. PS44 Funcional analysis of EHD1, a new candidate gene for bipolar disorder. Takumi Nakamura1, Tadafumi Kato2, Kazuo Nakajima2, Tomoyo Sawada2, Takashi Tsuboi1 1The University of Tokyo, Japan, 2RIKEN Brain Science Institute, Japan Abstract Bipolar disorder is a common neuropsychiatric disorder characterized by manic and depressive episodes with life time prevalence of around 1%. Although the pathogenesis of bipolar disorder is not well understood, genetic factors are known to be important in bipolar disorder. Recently, a de novo frameshift mutation in EHD1 (Eps15 homology domain 1), predicted to generate a truncated EHD1 protein, was reported by a trio-based exome sequencing study of bipolar disorder. EHD1 possesses the EH domain including the EF-hand calcium binding domain, and plays important roles in the recycling of receptors from endosomes to the plasmaBipolar disorder is a common neuropsychiatric disorder characterized by manic and depressive episodes with life time prevalence of around 1%. Although the pathogenesis of bipolar disorder is not well understood, genetic factors are known to be important in bipolar disorder. Recently, a de novo frameshift mutation in EHD1 (Eps15 homology domain 1), predicted to generate a truncated EHD1 protein, was reported by a trio-based exome sequencing study of bipolar disorder. EHD1 possesses the EH domain including the EF-hand calcium binding domain, and plays important roles in the recycling of receptors from endosomes to the plasma membrane and the cell differentiation. In the present study, we analyzed the function of mutant EHD1 protein which is predicted to be generated by a mutation identified in a bipolar disorder patient. We determined the recycling endocytosis activity in EHD1 mutant-expressing PC12 cells by using Alexa488-conjugated transferrin and fluorescence activated cell sorting. Our preliminarily experiment showed that the EHD1 mutant might inhibit the activity of recycling endocytosis. We also found that the EHD1 mutant-expressing PC12 cells significantly inhibited the efficiency of nerve growth factor-induced differentiation. These findings suggest that the mutation of EHD1 found in a patient with bipolar disorder impairs the function of EHD1 in differentiation of PC12 cells. The present results could be shed light on the pathophysiological mechanisms of bipolar disorder at the cellular level. PS45 SLC1A2 Promoter is Hypomethylated in Bipolar Disorder with Comorbid Addiction Marin Veldic1, Jennifer Ayers-Ringler1, Nicoli Carneiro1, Doo-Sup Choi1, YuBin Choi1, Mark Frye1, Yun-Fan Jia1, 1Mayo Clinic, USA Abstract Specific Objective: SLC1A2 encoding excitatory amino acid transporter 2 (EAAT2), the principal transporter clearing synaptic glutamate, is a candidate gene for bipolar disorder (BD). The aim of this study was to examine the differences in methylation of the SLC1A2 promoter between BD and non-psychiatric subjects (NPS). Methods: 150 BD subjects from the Mayo Clinic Bipolar Biobank were equally divided into five groups: (1) BD without comorbid alcohol use disorder (AD), nicotine use disorder (ND), or binge eating disorder (BE); (2) BD+AD; (3) BD+ND; (4) BD+ND+AD; and (5) BD+BE. Mayo Clinic Community Biobank provided NPS samples (n=32). First, we performed bisulfite conversion and methylation-sensitive high-resolution melt (HRM) PCR to examine methylation status of the two SLC1A2 promoter regions. To validate our findings, we employed TA cloning and DNA sequencing to map the whole 156 CpG sites in the approximately 2kb promoter region of the SLC1A2. One-way analysis of variance (ANOVA) and general linear regression model were used for the statistical analysis. Summary of Results: HRM analysis in the CpG island between -1759 and -1468 revealed difference between the groups (p=0.0003). BD with comorbidities were hypomethylated compared to BD, while females showed hypermethylation (p=0.036). HRM PCR in CpG island between -785 and -654 revealed hypomethylation in BD with comorbidities in comparison to BD (p<0.0001). BD was a predictor of hypermethylation (p=0.035). In our complete sequencing study, we identified that CpG site #6 was hypermethylated in BD compared to NPS (p=0.05). CpG sites #3 (p=0.05) and #156 (p=0.04) were hypomethylated in BD+AD+ND compared to NPS. CpG sites #6 (p=0.01) and #48 (p=0.03) were hypomethylated in BD+AD+ND compared to BD. Conclusions: DNA methylation is altered in two distinct regions of SLC1A2 promoter of BD patients. Addiction comorbidities have a significant impact on the level of promoter hypomethylation. HRM analysis was validated through bisulfite sequencing. PS46 Distinct and shared morphometric biomarkers of depressed individuals with bipolar disorder and major depressive disorder Koji Matsuo1, Yusuke Fujita1, Kenichiro Harada1, Takeshi Inoue2, Hiroshi Kunugi3, Ichiro Kusumi4, Hisashi Narita4, Go Okada5, Yasumasa Okamoto5, Miho Ota3, Masahiro Takamura5, Yoshifumi Watanabe1, Hirotaka Yamagata1, Shigeto Yamawaki1 1Yamaguchi University, Japan, 2Tokyo Medical University, Japan, 3National Center of Neurology and Psychiatry, Japan, 4Hokkaido University,Japan, 5Hiroshima University, Japan Abstract Objective: Diagnostic differentiation between depressed patients with bipolar disorder or major depressive disorder is a critical issue, as misdiagnosis may result in inappropriate treatment and poor outcome. Specific biomarkers of each disorder that would allow differential diagnosis have not been identified. The aim of study is to determine whether depressed patients with bipolar disorder or major depressive disorder show distinct morphometric abnormalities. Methods: 569 depressed patients with major depressive disorder, 140 depressed patients with bipolar disorder, and 717 age-matched healthy participants were studied. We examined gray matter volume using voxel-based morphometry. Group classification was performed using a support vector machine algorithm.Objective: Diagnostic differentiation between depressed patients with bipolar disorder or major depressive disorder is a critical issue, as misdiagnosis may result in inappropriate treatment and poor outcome. Specific biomarkers of each disorder that would allow differential diagnosis have not been identified. The aim of study is to determine whether depressed patients with bipolar disorder or major depressive disorder show distinct morphometric abnormalities. Methods: 569 depressed patients with major depressive disorder, 140 depressed patients with bipolar disorder, and 717 age-matched healthy participants were studied. We examined gray matter volume using voxel-based morphometry. Group classification was performed using a support vector machine algorithm.