Molecular Genetic Studies On The Dysregulation Of MEF2C Gene Expression And Acute Myocardial Infarction

Background:Coronary artery disease(CAD)is a common cause of morbidity and morbidity in cardiovascular disease.Especially in todays fast-paced life.It is one of the leading causes of global human death and dysfunction.Acute myocardial infarction(AMI)which is mainly caused by atherosclerotic plaque rupture is a serious type of coronary heart disease?MEF2C gene which is a member of the MEF2 subfamily is considered to be one of the important transcription factors for early heart development[1]-[2].In the process of gene expression,The change of promoter level may influence gene expression level.Therefore,this study explores the relationship between the development of myocardial infarction and MEF2C gene by studying the genetic variation of the gene promoter.Objective:We investigated the sequence variation of MEF2C gene promoter in AMI patients and normal controls,constructing expression vectors and detecting the changes of expression level to explore the pathogenesis of this gene in AMI.Methods:1.A total of 406 patients with AMI and 422 normal controls were recruited.Clinical data were collected and the whole gene promoter DNA was extracted.2.Primers were designed according to the promoter sequence of the MEF2C gene in the NCBI gene database.We amplified the target fragment by PCR to find the DNA sequence variants with directly sequencing.The MEF2C promoter wild-type fragment and sequence mutation site were constructed into PGL3-basic rEporter gene vector.The rEporter gene vector and the internal reference plasmid PRL-TK were instantly co-transfected into HEK293 cells and H9C2 cells by lipofectamine to detect luciferase activity.3.A biotin-labeled probe sequence for the mutation site in the AMI group was designed and the binding of the transcription factor was examined by EMSA.Results:1.Eleven DSVs were found by sequencing:Two novel heterozygous DSVs[g.88884584G>A?g.88883666C>G]and one SNP[g.88884379A>G(rs114694170)]were only identitied in AMI.Three novel heterozygous DSVs[g.88884127G>C?g.88884117G>C?g.88883924G>T]and two SNPs[g.88884426C>A(rs777-237657)?g.88884274G>A(rs137991329)]were found in normal controls,but in AMI?Three SNPs[g.88884587G>T(rs3814288)>g.88883758T>C Crs80043958)?g.88883519C>T(rs78821200)]were found either in AMI or in controls with similar statistics(P>0.05).2.With the detection of luciferase activity in transfected HEK293 cells and H9C2 cells,The DSVs significantly reduced the transcriptional activity of MEF2C promoter in the AMI(P<0.01).The DSVs found only in the control group did not significantly alter the transcriptional activity of the MEF2C promoter(P>0.05).3.EMSA test found that:in the AMI group,g.88884584G>A did not significantly change the binding site of the relevant transcription factor,but g.88883666C>G may eliminate the binding site of PPARG::RXRA?YY1 transcription factor.g.88884379A>G(rs114694170)may weaken the binding site of SP1B.NFATC2 transcription factor.Conclusion:The sequence variations of MEF2C gene promoter which may alter its transcriptional activity and the binding of the relevant transcription factors play an important role in the development and progression of myocardial infarction.