Study On Susceptibility Genes And Risk Genetic Variants Of Schizophrenia And Bipolar Disorder

Objective:As being the common severe psychiatric disorder,both of schizophrenia?SCZ?and bipolar disorder?BD?are tipical multi-gene complex diseases with the high degree of heritability range from 80%to 85%,however,their etiology mechanisms are still unclear.Therefore,we aim to screening the susceptibility genes and risk genetic variants which may be related to the occuurence of SCZ and BD by informatic analysis,then detect the mRNA expression level of the genes and the association between the variants and the risk of developing SCZ and BD base on Han Chinese populations in Guangxi,and next preliminarily explore the biological fuction of the risk variants through cell experiment.The present study may provide some more basic data for the molecular machenism of SCZ and BD.Methods:Part one:Screening the shared genes between SCZ and BD using bioinformatic analysisTo identify the susceptibility genes related to SCZ and BD with the help of two online databases:A Catalog of Published Genome-Wide Association Studies and Genetic Association Database.And then,to identify the shared core genes of SCZ and BD by conducting the protein-protein interactions?PPI?network analysis and SCZ-and BD-related GEO gene arrays analysis.Finally,to selecte the polymorphisms of the core genes using Hapmap website,Haploview 4.2software and other related websites for predicting the gene functions.Part two:Association study of susceptibility genes and risk variants of SCZ and BDThe present case-control study included the study subjects in Guangxi,all of them were Han Chinese.The relative expression of the 13 core genes was detected in the 50 SCZ,50 BD and 50 controls using qRT-PCR,and then ROC analysis was used for the potential diagnostic biomarkers of SCZ and BD.The genotype of the 28 polymorphisms was finished by Sequenom MassARRAY genotyping methods among 548 SCZ,512 BD and 598 henthy controls.The data were analyzed by SPSS 16.0 for desktop and the PLINK?http://pngu.mgh.harvard.edu/^purcell/plink/?.Part three:Exploring the biological fuction of the risk variants of SCZ and BDTo predicte the most potential miRNA for the variants at 3'UTR of the genes and transcription factor for the variants at 5'near of the gene.Then,we constructed the expression vectors,conducted dual luciferase reporter assay to dected the combination of mi RNA and the corresponding variant at gene 3'UTR region,as well as the combination of the transcription factor and the promotor variants at gene 5'near region in 293T cell line.The SPSS 16.0 for desktop was used for data analysis.Results:Part one:Screening the shared genes between SCZ and BD using bioinformatic analysis?1?Through online databases screening,GEO gene arrays analysis and PPI network analysis,a total of 13 shared core gene were identified to be related to SCZ and BD,including GNAI1,PRKCA,PRKCB,PRKCZ,CTNNB1,PIK3R1,GRB2,YWHAB,YWHAZ,LYN,FYN,SRC,and TP53 genes.?2?Taking several factors?eg.fuctional regions of the variants?into consideration,28 polymorphisms of the 13 core genes were identified for later exploration.Part two:Association study of susceptibility genes and risk variants of SCZ and BD?1?When compared to the control group,the mRNA expression of GNAI1?PRKCA?PRKCB?CTNNB1?YWHAZ?GRB2?LYN and FYN genes significantly differed in SCZ group and control group?all P<0.05?,while of GNAI1?PRKCA?PRKCB?PRKCZ?CTNNB1?PIK3R1?YWHAB?YWHAZ?FYN and TP53 genes significantly differed in BD group and control group?all P<0.05?.?2?The results of ROC analysis showed that GNAI1 gene?AUC,sensitivity,specificity was 0.81,0.85,0.66,respectively?may be the potential diagnostic biomarker for SCZ,while GNAI1 gene?AUC,sensitivity,specificity was 0.92,0.98,0.74,respectively?,PRKCA gene?AUC,sensitivity,specificity was 0.88,0.91,0.90,respectively?,FYN gene?AUC,sensitivity,specificity was 0.75,0.71,0.82,respectively?,PIK3R1 gene?AUC,sensitivity,specificity was 0.92,0.91,0.80,respectively?,CTNNB1 gene?AUC,sensitivity,specificity was 0.73,0.65,0.92,respectively?,PRKCZ gene?AUC,sensitivity,specificity was 0.76,0.60,0.82,respectively??TP53 gene?AUC,sensitivity,specificity was 0.79,0.65,0.90,respectively?may be the potential diagnostic biomarker for BD.?3?The genotypic distribution of PRKCA gene variant rs7342847?P=0.034?was significantly differ in SCZ and control group;while the genotypic distributions of rs7342847?PRKCA;P=0.034?,rs3756668?PIK3R1;P=0.038?,and rs1042522?TP53;P=0.016?were differ in BD and control group.?4?The association analysis between gene variants and SCZ or BD:?1?PRKCA gene variants rs7342847(added model:P_adj=0.011;dominant model:P_adj=0.041;recessive model:P_adj=0.032;allelic model:P=0.040)and rs8464?allelic model:P=0.049?were associated with SCZ,while rs7342847was associated with BD(dominant model:P_adj=0.031).?2?PRKCB gene variant rs2575390 was significantly associated with SCZ occurrence(added model:P_adj=0.037;dominant model:P_adj=0.022;allelic model:P=0.044).?3?CTNNB1 gene variant rs2953 was sooociated with SCZ(added model:P_adj=0.026;dominant model:P_adj=0.026;allelic model:P=0.025).?4?PIK3R1 gene variant rs3730089 was associated with SCZ was found(recessive model:P_adj=0.040).?5?GRB2 variant rs7219 was associated with the occurrence of SCZ(added model:P_adj=0.026;dominant model:P_adj=0.023;allelic model:P=0.027).?6?TP53 gene variant rs1042522 was significantly associated with BD(added model:P_adj=0.005;dominant model:P_adj=0.019;recessive model:P_adj=0.023;allelic model:P=0.004).Part three:Exploring the biological fuction of the risk variants of SCZ and BDAfter successfully constructed the expression vectors,the results of dual luciferase reporter assay in 293T cell lines showed that:?1?Compared with the vector transfected with rs7342847?at PRKCA gene3'UTR?normal control or with rs7342847 mutation,miRNA-1909 could bind to rs7342847 wildtype,contribubting to the reduction of relative luciferase activity?both P<0.005?.?2?Compared with the vector transfected with rs8464?at PRKCA gene3'UTR?normal control or with rs7342847 mutation,miRNA-450a-1 could bind to rs8464 wildtype,contribubting to the reduction of relative luciferase activity?both P<0.005?.?3?Compared with the vector transfected with rs2953?at CTNNB1 gene3'UTR?normal control or with rs2953 mutation,miRNA-485 could bind to rs7219 wildtype,leading to a reduction of relative luciferase activity?both P<0.005?.?4?Compared with the vector transfected with rs7219?at GRB2 gene3'UTR?wildtype,mi RNA-1288 could bind to rs7219 mutation,reducing a reduction of relative luciferase activity?P=0.001?.?5?Compared the vector transfected with promotor variant rs2575390?at PRKCB gene 5'near?wildtype and promotor variant rs2575390 mutation,no significant change of relative luciferase activity was detected?P>0.05?.Moreover,after tranfected with transcription factor CEBPA,the relative luciferase activity did not show a significant alteration?P>0.05?.Conclusions:?1?The mRNA expression of YWHAZ?GRB2?LYN genes was related to SCZ occurrence,PRKCZ?PIK3R1?YWHAB?TP53 genes was related to BD occurrence,while GNAI1?PRKCA?PRKCB?CTNNB1?FYN genes was related to both SCZ and BD occurrence,indicating that these genes may be involved in the pathogenesis of SCZ and BD.?2?The mRNA expression of GNAI1 gene could be the potential biomarker for SCZ diagnosis,while the mRNA expression of GNAI1?PRKCA?FYN?PIK3R1?CTNNB1?PRKCZ?TP53 genes could be the potential biomarkers for BD diagnosis.?3?Rs8464,rs2575390,rs2953,rs3730089,and rs7219 were associated with SCZ susceptibility,rs3756668 and rs1042522 were associated with BD susceptibility,while rs7342847 was the shared risk variant of SCZ and BD susceptibility.?4?miRNA-1909,miRNA-450a-1,miRNA-485 and miRNA-1288 could respectively bind to rs7342847,rs8464,rs2953 and rs7219 at 3'UTR of their corresponding target genes,and then contributed to a reduction of relative luciferase activity.This indicated that these miRNAs may regulate its targeted gene expression by binding to the variants in gene 3'UTR region,which finally cause SCZ and/or BD.