Functional Genetic Variants Within The LncRNA-MIAT Gene Promoter In Acute Myocardial Infarction

Part1 Association of LncRNA-MIAT gene promoter sequence variants with acute myocardial infarctionBackground:Cardiovascular disease(CVD)is a major disease that seriously affect human health.As known,several nongenetic factors,such as smoking,hyperlipidemia,hypertension,diabetes mellitus(DM),and obesity,are closely associated to the CVD incidence.With the completion of the Human Genome Project,it has been found that CVD is significantly associated with genetic factors,so a large number of studies are currently conducted to analyze the genetic etiology of CVD.Long non-coding RNAs(LncRNAs)play an important role in human diseases.A large number of studies have shown that lncRNA involved in occurrence of CVD,but the molecular mechanisms need to further research.GWAS analysis has shown that LncRNA-MIAT(myocardial infarction association transcript)links with CVD,especially in acute myocardial infarction(AMI).LncRNA-MIAT participates in the process of diseases by many mechanisms as competing endogenous RNAs to regulate expression of gene,promoting cell proliferation,inflammatory protein production,and inhibiting autophagy.Therefore,we speculated that the LncRNA-MIAT levels may be associated with development and prognosis of AMI.In this study,LncRNA-MIAT gene promoter was analyzed in AMI patients and controls,to find and research the DNA sequence variants(DSVs)of promoter of MI AT in two groups.Objective:Case-control study was used to analyze the correlation between DSVs of lncRNA-MIAT gene promoter and AMI by proliferation of DNA and directly sequencing in two groups.Methods:1.220 AMI patients and 220 normal controls were admitted in the Affiliated Hospital of Jining medical University,and everyone receive 5ml fasting hemospasia for extracting genomic DNA2.The human lncRNA-MIAT gene promoter sequence was downloaded from NCBI,the corresponding PCR primers were designed and synthesized.3.The lncRNA-MIAT gene promoter was amplified by Polymerase Chain Reaction(PCR),and the size was confirmed by agarose gel electrophoresis.The PCR products were sent to Shanghai Sangon Biotech for sequencing.The sequence varianrts were found and recorded.4.Statistical analysis was performed using SPSS 20.0 to analyze.Results:Due to incomplete sequencing or unstable baseline chromatograms,218 samples of AMI patients and 212 samples of the control group were finally included in this study.There was no significant difference in triglyceride(TG),low-density lipoprotein(LDL),and BMI.However,significant difference was found in gender,age,total cholesterol(TC),and high-density lipoprotein(HDL).A total of 16 DSVs were found in the study,including 10 single nucleotide polymorphisms(SNPs).Two of the DSVs were only found in the case group,which were g.3997C>T,g.4917G>C There were 5 DSVs only in the control group,which were g.4270C>T,g.4360G>T(rs1055293700),g.4665C>T,g.4874G>A,g.5159G>T.There were 9 DSVs in both groups,all of which are SNPs,inlcuding g.4004C>T(rs56371714),g.4063T>C(rs5752375),g.4112C>T(rs55892869),g.4137T>C(rs9608515),g.4359insG(rs151057042),g.4445A>T(rs215 7598),g.4453insA(rs15 0465374),g.4675C>T(rs5761664),g.4933T>C(rs8142890).Statistical analysis was performed on all SNPs,for the rs1055293700 only appeared in the control group,the other 9 SNPs were statistically analyzed finally.Chi-square test was performed on the gene frequencies of the polymorphisms in two groups.It was found that there was a statistically significant difference of rs5752375 and rs9608515(P values were 0.02and 0.04,respectively)between two groups.The higher frequency of alles was defined as wild type.Logistic regression analysis was used to analyze the association between AMI and all polymorphisms.There was a significant correlation between rs5752375 and rs9608515 polymorphisms and AMI,while the correlation was not found in other SNPs rs56371714,rs55892869,rs151057042,rs2157598,rs150465374,rs5761664,rs8142890.For the rs5752375 locus,the risk of TT genotype was 3.91 times higher than CC genotype in AMI[OR=3.91,95CI(1.27,12.02),p=0.02].For rs9608515 locus,TT genotype was higher than CC genotype,the risk of AMI increased 3.11 times[OR=3.11,95CI(1.10,8.74),p=0.03].After adjusting for risk factors such as gender,age,smoking,hypertension and diabetes,the ratio of LDL and HDL,the correlation was analyzed again.The difference was still statistically significant in rs5752375 and rs9608515 polymorphisms,and no relation was found in other polymorphisms.For the rs5752375 locus,the TT genotype was found to be a risk factor for AMI compared with the CC genotype[OR=7.11,95%CI(1.64,30.79),P=0.01];for the rs9608515 locus,the TT genotype is a risk factor for the onset of AMI[OR=5.56,95%CI(1.43,21.64),P=0.01].The other sites rs56371714,rs55892869,rs151057042,rs2157598,rs150465374,rs5761664,rs8142890 were still not associated with AMI.Conclusion:The lncRNA-MIAT gene promoter polymorphisms,rs5752375 and rs9608515,were significantly associated with AMI in Chinese Han population,and TT genotype of two polymorphisms was a risk factor for AMI,while no significant statistical correlation was found in other SNPs,This data might be of great value for the early diagnosis of AMI.Part 2 Functional genetic variants of the lncRNA-MIAT gene promoter in acute myocardial infarctionBackground:AMI is the most serious type of CAD,and early diagnosis and treatment have significant correlation with prognosis.At present,the diagnosis of AMI is mainly based on myocardial enzymology,electrocardiogram and symptom of patient,but these indicators mainly appear after occurance of disease,so there is no evidence for early diagnosis.Furthermore,coronary interventional therapy was used and the stents is widely used for the treatment of AMI,however,the individual differences among patients always occurance,the prognosis of some patients is still poor.At present,with the introduction of precision medicine,accurate diagnosis and precise treatment of AMI is a new direction of current research.Precision medicine attempts to provide evidence for individual medical services through early diagnosis,early prevention,and early treatment by molecular biology methods.In the first part of this study,some new lncRNA-MIAT-related sequence variants(DSVs)were discovered in AMI patients.Therefore,this part of the experiment performed a functional analysis of newly discovered DSVs.Objective:Functional analysis of DSVs carried out by constructing a luciferase reporter gene vector,transfecting the cultured cells and measuring their transcriptonal activities of lncRNA-MIAT gene promoter.Methods:1.Download the human MIAT gene promoter sequence from NCBI,design the PCR primer sequence,and add the appropriate restriction enzymes sites at both ends,and submit the designed primer sequences to Shanghai Sangon Biotech for synthesis;2.The sample containing the DSVs of the MIAT gene promoter sequence was amplified,the size was verified by agarose gel electrophoresis,and the product of PCR was subjected to gel recovery and purification;3.The gel-recovery product of the appropriate size of the fragment was separately ligated into the T-Vector(pMDTM19)to construct an expression vector of the MIAT gene promoter;4.The constructed vector was transformed into DH5a competent cells and cultured in LB solid culture dish.Single colonies were selected for colony PCR,and the appropriate size of the individual colonies were cultured and sent to Shanghai Sangon Biotech for sequencing.Conditional expression vectors were selected.5.The plasmid was purified and digested by appropriate restriction enzymes to verify the size of the digested product by agarose gel electrophoresis;6.The target fragment of the MIAT promoter after the recovery of the gel is respectively subcloned into PGL3 expression vector;7.Filtering the eligible vectors by the same method 4;8.The constructed PGL3 reporter vector and the internal reference pRL-TK were co-transfected into HEK293 and H9c2 cells respectively,and the transcriptional activity of the MIAT promoter was examined.Results:The eligible vectors containing DSVs were successfully constructed,which were PGL3-WT,PGL3-4917C,PGL3-3997A and PGL3-4874A.The constructed luciferase reporter and the internal reference pRL-TK were transfected into HEK293 cells and H9c2 cells,and the fluorescence values were observed and statistically analyzed.It was found that the DSVs which found in AMI could change the transcriptional activity of the lncRNA-MIAT gene promoter.However this effect was not observed in control.It was also found that the transcriptional activity of DSVs has cell specific.The change of transcriptional activity of g.4917G>C was observed in HEK-293 cells,and this phenomenon was not observed in H9c2 cells.Both g.3997C>T and g.4917G>C reduced the transcriptional activity of the lncRNA-MIAT promoter in H9c2 cells.Conclusion:The DSVs of lncRNA-MIAT gene promoter in AMI patient can change its transcriptional activity,affect the expression of this gene.Part 3 Study of molecular mechanism between myocardial infarction and DSVs of LncRNA-MIAT gene promoterBackground:Based on the previous study,it was found that the lncRNA-MIAT gene promoter variants can change the transcriptional activity of the promoter.Therefore,this part uses bioinformatics and gel migration experiments to further explore the influence of related sequence variants on promoter transcriptional activity,revealing the molecular mechanism between AMI and DSVs of LncRNA-MIAT gene promoter.Objective To study the mechanism between AMI and DSVs of LncRNA-MIAT gene promoter,providing a new idea for the pathogenesis of AMI.Methods1.Analyze the transcription factor of the LncRNA-MIAT promoter variant by using the JASPAR program(http://jaspar.genereg.net/)online site;2.According to the location of the two sequence variants in AMI,the biotin labeled probe was designed and synthesized by Shanghai Sangon Biotech;3.Extract the nuclear proteins of two different source cells(HEK-293 cells,H9c2 cells);4.The labeled biotin probe was separately bound to the nuclear protein,and the reaction mixture was subjected to a gel migration experiment(EMSA).The EMSA experiment showed the different migration in the gel.The gel was transferred to a membrane,and to observe the binding of the biotin-labeled probe to the nuclear protein according to the principle of biotin luminescence.Results:According to the online analysis of LncRNA-MIAT gene promoter with JASPAR program,it is predicted that the presence of DSVs in AMI may alter transcription factor binding,mainly in the addition of partial transcription factors,elimination of partial transcription factors or alteration of transcription factors binding.DSV g.3997C>T may eliminate the binding sites of transcription factors,such as E2F1,KLF5,SP1,SP8,TBX15,ZNF740 and ZBTB7C,create the binding of transcription factors such as FOXD2,EGR2,EGR3,NFIC,NFIX,SP3,and change the binding of transcription factors such as KLF9,KLF4,KLF16,EGR1,MG A.DSVg.4917G>C may eliminate the binding of KLF16,TFDP1,MZF1,SP3,PAX5,SP8,THAP1,TBX4,TBX5,TBX15,MGA,create the binding of ELK1,E2F4,ELK4,ETV5,ELF1,TEAD1,RORC,TFAP2C,TFAP2B,and ZBTB7A,and altere the binding of E2F6,E2F1,E2F4,EGR1,CTCFL,KLF5,SP1,SP2,TFAP2A,and ZNF263.The results of EMSA showed that the newly discovered LncRNA-MIAT gene promoter DSVs in AMI can change the binding of transcription factors,and the effect of g.3997G>C on transcription factor binding is obvious.Conclusions:According to the analysis of the JASPAR program website,the LncRNA-MIAT gene promoter variants may change the transcription factor binding site.EMSA experiments further confirmed that the LncRNA-MIAT gene promoter DSVs may change the binding of transcription factors and affect the expression of LncRNA-MIAT gene.Therefore,LncRNA-MIAT gene promoter DSVs plays an importatn role in in the pathogenesis of myocardial infarction.Conclusion:The lncRNA-MIAT gene promoter DSVs found in AMI patients may alter the binding of transcription factors and affect the expression of the lncRNA-MIAT gene.