Association Of Regulatory Region In The Human Serotonin Receptor 1B(HTR1B)gene With Schizophrenia And The Forensic Significance

Background: Schizophrenia is a chronic,disabling psychotic disorder that involves sensory perception,cognition,emotion,and behavior,and is characterized by inconsistency or disconnection between mental activity and the environment.About 210 million people worldwide suffer from schizophrenia,which has caused a serious social burden.The etiology of schizophrenia is complex,the Etiology of schizophrenia is not clear and also lack of efficient treatment.Therefore,it is still important to further explore the Etiology of schizophrenia.In forensic medicine,schizophrenia is also the most common mental illness in psychiatry judicial identification,accounting for 1/3 ? 1/2 of the total cases involved in legal issues.Schizophrenia is a complex genetic disease involves in multiple genes,and the cause of schizophrenia remains unclear.But it's generally believed to be related to several neurotransmitter system disorders,including dopamine,5-hydroxytryptamine,glutamate,gamma-aminobutyric acid.Among them,the serotonin system is one of the most important neurotransmitter systems systems in humans,and plays a vital role in various brain activities.As one of the most important part of the serotonin system,the 5-hydroxytryptamine receptors can divided to seven categories including 14 subtypes.Among them,5-hydroxytryptamine 1B receptor(5-HT1B)is suggested to be associated with a variety of emotional and psychological disorders,including attention deficit hyperactivity disorder(ADHD),antisocial personality disorder,aggressive behavior,bipolar disorder,anxiety/depression,schizophrenia,substance abuse disorder,5-HT1 B is also a common target for antipsychotics drugs.However,the results derive on the genetic correlation between HTR1 B and schizophrenia are not unified.Also there are inefficient studies on mechanisms in HTR1 B regulation Therefore,this study attempts to explore the polymorphism of HTR1 B in the northern Han Chinese population,and its relationship between HTR1 B and schizophrenia.In the meantime,the polymorphisms of HTR1 B 5'and 3'regulatory regions and the potential functional regions have been explored for their effects on regulation of gene expression.Methods: This study was conducted on 310 schizophrenic patients and 313 healthy people from the northern Han Chinese population.For HTR1 B gene 5 ' regulatory region of 2285 bp and 3' regulatory region of 1277 bp two fragments of DNA sequencing,the survey for HTR1 B polymorphism and its relationship with schizophrenia if northern Han Chinese population was performed by DNA sequencing of a 2285 bp fragment in the 5'-regulatory region and a 1277 bp fragment of the 3' regulatory region of HTR1 B.Based on the result of DNA sequencing analysis,recombinant vectors of the 5' and 3' regulatory region haplotype were established.Gene expression was quantified using dual luciferase reporter assay system to research the effect of HTR1 B polymorphisms on gene expression.In addition,based on the idea of gene segmentation research,recombinant vectors of different length fragments of the 5' and 3' regulatory region of the HTR1 B were constructed.The dual luciferase reporter assay system was also used to investigate the effects of potential functional sequence of HTR1 B on regulation of gene expression.Results: This study detected the 14 SNPs,wherein rs1778258 A allele and genotype AG+AA distribution in male patients with schizophrenia is significantly higher than female patients(p=0.012,p=0.015).Both A allele and genotype AG+AA increased the risk of disease(OR=1.986,OR= 2.061).The results of linkage analysis showed that rs17273700,rs11568817,rs9361234,and rs58138557 have a strong linkage in the northern Han Chinese population,and these four SNPs are more closely linked to rs130058 in schizophrenic patients than healthy people.In addition,rs6297 and rs1778258 also have a considerable chain relationship.When exploring the function of the 5' regulatory region of the HTR1 B gene,it was found that 5' regulatory region polymorphism has a regulatory effect on transcriptional activity.Among the six haplotypes found in the northern Han Chinese population consisting of rs4140535,rs1778258,rs17273700,rs1228814,rs11568817,and rs130058,all other haplotypes have differences in transcriptional activity compared to the major haplotype.Then rs17273700-rs11568817 C-G and rs1228814 A were suggested to promote HTR1 B gene expression,while rs4140535 C,rs1778258 A and rs130058 T inhibit HTR1 B gene expression.Moreover,this study suggests that the core transcriptionally promoter region of the HTR1 B gene is located within + 341 ? + 505 bp from transcriptional initiation to downstream.There are expression activation regions in 5' regulatory region-603?-316 bp from transcriptional initiation to upstream,and there are expression suppression regions in-1587?-1371 bp,-1149?-894 bp,-894?-603 bp,-39? +130bp,+130? +341bp regions.The HTR1 B 3' regulatory region polymorphism is also associated with gene expression activity.Among the haplotypes in the northern Han Chinese population consisting of rs6297,rs3827804,rs140792648,rs9361234,rs76194807,rs58138557,and rs13212041,the relative fluorescence intensity of haplotype A-G-Del-C-T-Ins-A is higher than the major haplotype A-G-Del-C-G-Ins-A,and the relative fluorescence intensity of the haplotype G-G-Del-C-G-Ins-G is lower than the major haplotype.rs76194807 and rs6297 are considered as potential functional polymorphims,rs76194807 T up-regulates gene expression levels,while rs6297 G down-regulates gene expression levels.Then,it suggests that there are potential regulatory sequences that have inhibitory effects on gene expression in +3143bp ?+3285bp,+2887? +3008bp,especially +2440? +2769bp,+1953? +2311bp from transcriptional initiation to downstream of HTR1 B.Conclusion: 1.HTR1 B gene is potentially correlated with schizophrenia in the northern Han Chinese population.2.The 5 ' regulatory region polymorphisms are involved in regulating gene expression,and,including the core transcriptional promoter region,there are multiple potential functional sequences on the 5' regulatory region of the HTR1 B.3.HTR1 B 3' regulatory region polymorphisms regulate gene expression.Multiple potential functional sequences exist in the 3' regulatory region of the HTR1 B,which likely to contain inhibitory regulatory elements.