Relationship Between SMAD4 Gene Polymorphism Loci Rs12455792 And The Generation And Development Of Thoracic Aortic Aneurysm And Dissection

Objective: This study was designed to analyze the relationship between candidate SNPs and susceptibility to thoracic aortic aneurysm and aortic dissection of Han population in China,and to summarize significant SNPs.Furthermore,this thesis aims to explore the mechanism of gene polymorphism and TAAD’s generation and development from function science.Methods: GWAS study was conducted according to the current well-known Hyper Gen study,and 20 SNPs associated with aortic diameter expansion or thoracic aortic dissection were selected as candidate SNPs.In 202 cases of thoracic aortic aneurysm and dissection and 400 cases of normal control,from Department of Cardiovascular Surgery,the First Affiliated Hospital of Soochow University,genomic DNA was extracted,SNP was classified with MALDI-TOF technology,and significant SNPs associated with TAAD generation of Han population in China were summarized.The mechanism of gene polymorphism and TAAD’s generation and development from function science was explored through bioinformatics prediction for significant SNPs,luciferase reporter,Western Blot,Movat dyed dyeing,apoptosis detection and other experiments.Result:In 20 candidate SNPs,rs12775710G>A,rs10757278G>A,rs12455792C>T,rs12913975G>A,rs1333049G>C,rs875971T>C were significant SNPs,and this loci was involved in the transcriptional regulation of SMAD4;risk bring to TAAD by rs12455792C>T locus mutation with SMAD4(CT and TT)is higher than that by wild type(CC genotype);rs12455792C>T locus mutation(CT and TT)risk the TAAD is higher than that of wild type(CC genotype);compared with the transfection of SMAD4 TRS-C allele SMAD4 TRS-C allele group,transfection group relative luciferase activity was significantly increased;compared with CC,SMAD4 with rs12455792C>T,TAAD expression in patients with T CT and TT loci in organization protein were significantly decreased,while the degradation of Versican the product(95 k Da and 70 k Da)was significantly increased;after transfection of si RNA-SMAD4 in HASMCs,there was a significant increase in the amount of protease expression of ADAMTS-4 cells,while the expression of ADAMTS-1 decreased.based on si RNA-SMAD4 after transfection,adding the ADAMTS-4 inhibitor would decease the expression of ADAMTS-4 evidently,and the expression of Versican degradation products was also decreased;aortic tissue Movat staining showed that the five rs12455792C>T,carrying different genotype groups(CC type,CT type,TT type)tissue of patients with TAAD were mainly black and brown.Compared with the CC type,the number of CT type and TT type in SMC film decreased,fiber density was significantly increased;after the transfection of si RNA-SMAD4 HASMCs early apoptosis ratio and late apoptosis ratio were significantly increased.Conclusion: The rs12455792C>T locus of SMAD4 gene is a genetic predisposing factor of TAAD in the Han population in China,and the susceptible allele is T.Compared with wild type(type CC),rs12455792C>T mutant(type CT and TT)can reduce the transcriptional activity of SMAD4 gene and reduce the expression of SMAD4.Low expression of SMAD4 may increase the apoptosis of VSMC and promote the accumulation of fiber in the aortic layer by increasing the protease ADAMTS-4,degrading Versican,thus participating in the development and development of TAAD.