Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Poster number: P.1.g.014 The effects of electroconvulsive seizure on the transcription of PAR family of bZIP genes via changes in Egr1 expression in the rat frontal cortex Tak Youn, Se Hyun Kim, Hong Geun Park, In-Won Chung, Yong Sik Kim Department of Psychiatry and Institute of Clinical Psychopharmacology, Dongguk University Ilsan Hospital, Goyang, Gyeonggi, Republic of Korea. INTRODUCTION Electroconvulsive therapy (ECT) • widely used to treat psychiatric disorders such as depression, mania, and schizophrenia. ECT affects vaious brain fucntions including affective, cognitive, and perceptive domains, as well as physiological and molecular functions such as excitability of neurons, neurogenesis, and cell survival in the brain The PAR family of bZIP genes • Defined by the presence of a proline and acidic amino acid–rich protein (PAR) domain is consist of three polypeptides, D-box binding protein (Dbp), thyrotroph embryonic factor (Tef), and hepatic leukaemia factor (Hlf) • Dbp plays an important function in the control of brain excitability, and was suggested as the candidate gene of mood disorder • Tef affects transcription of prolactin genes and thyroid-stimulating hormonebeta gene • Hlf was originally isolated from the leukemic blasts of pro-B cell acute lympho-blastic leukemia, and plays important role in cell survival and proliferation • Dbp, Tef, and Hlf display similar circadian and tissue-specific expression but have different target promoter preferences We hypothesized that the wide range of effects of ECT could be associated with genes with different functions under control of common regulatory mechanisms. In this study, we investigated the effect of a single and repeated treatment of electroconvulsive seizure (ECS), an amimal model of ECT, on the transcription of PAR family of bZIP genes in the rat frontal cortex. METHODS Male Sprague-Dawley rats (150-200g) ECS treatments • Single ECS treatment was applied to examine the acute changes. To investigate the chronic changes, ECS and sham groups were treated once per day for 10 days at the same time during a day (12:00-13:00) for a total of ten times (E10X). The rats were decapitated 24 h after the last treatment. Quantitative real-time PCR • mRNA expression level was examined with qPCR. Immunoblot analysis • Protein level was examine with immunoblot analysis. Analysis of Egr1 binding motif on the promoter regions of PAR bZips • The promoter regions of PAR bZip genes were analyzed to find Egr1 binding motif on them. The nucleic acid sequence of each gene’s promoter region which includes 2000 bps upstream from transcription starting site (TSS) was obtained from the web site UCSC Genome Bioinformatics (genome.ucsc.edu) and transcription factor binding motifs were searched by using MatInspector program (Genomtix, www.genomatix.de). Chromatin immunoprecipitation (ChIP) • Egr1 occupancy of the promoter regions of examined genes were examined with ChIP anlysis RESULTS Acute and chornic effects of ECS on the expression of Dbp, Tef, and Hlf • Single treatment of ECS (E1X) induced time-dependent changes in the mRNA expression level of Dbp, Tef, and Hlf in rat frontal cortex Transcription factor binding sites analysis • We examined the transcription factor binding sites within the promoter regions (encompassing 1,500 bp from transcription start site) of Dbp, Tef, and Hlf genes. The binding sites for early growth response-1 (Egr1), Rev-Erbα, and RAR-related orphan receptor alpha (Rorα) were commonly found in the promoter regions. Acute and chronic effects of ECS on Egr1 expression • mRNA level of Egr1 was gradually increased until 60 min and decreased thereafter by E1X • Dcreased at 24 h after E10X as previously reported • These findings suggest that Egr1 could negatively regulate the transcription of Dbp, Tef, and Hlf genes. Increased Egr1 binding to the Egr1 motif on PAR bZip promoter regions • In 2000 bps upstream from transcription starting site (TSS) on PAR bZip promoter region, Egr1 binding motifs were observed two at Dbp promoter region, one at Hlf promoter region, and four at the Tef promoter region. • Egr1 binding level to the motif on promoter region of PAR bZip genes were investigated by ChIP assay at the time when peak of Egr1 expression observed, 30 min after single ECS, in the rat frontal cortex. Compared to sham, Egr1 binding to the motif on Dbp gene promoter region (t = 2.76, p < 0.05) was increased as well as to the motif on Hlf (t = 2.96, p < 0.05) and Tef promoter (-34, t = 2.51, p < 0.05; -492, t = 2.16, p = 0.07; -546, t = 2.82, p < 0.05; -767, t = 4.68, p < 0.05) region at 30 min after ECS Expression levels of PAR bZips mRNA at the reduced expression of Egr-1 in frontal cortex of Egr1 KO mouse • In order to know PAR bZip expression level of mRNA in the condition of reduced Egr1 expression, we examined the expression level of PAR bZip in frontal cortex of egr1 KO mouse. In egr1 KO mouse frontal cortex, Dbp, Tef, and Hlf were increased (t = 2.38, p < 0.05; t = 3.55, p < 0.05; t = 2.48, p < 0.05; respectively) compared to wild type • mRNA levels of three genes were significantly decreased at 60 min after ECS. The repeated ECS treatments for 10 days (E10X) significantly upregulated mRNA levels of Dbp, Tef, and Hlf compared to those in sham control group at 24 h after E10X in rat frontal cortex The expression of three genes showed same pattern of changes in response to ECS treatment, indicating possible common regulatory mechanisms. CONCLUSION ECS treatments affects the transcription of Tef, Hlf, and Dbp, via negative transcriptional regulation of Eg1 in the rat frontal cortex. The common effects of ECS on the different members of PAR family of bZIP genes could provide understanding on the various effects of ECT on various cognitive, mood, and physical domains, which will require further functional studies.