| BackgroundCoronary artery disease is a common complex disease that is caused by interactions of environmental and genetic factors. Myocardial infarction (MI) is a restrictive phenotype of coronary artery disease. To date, a group of genes and genetic loci have been associated to MI. However, the genetic causes and underlying molecular mechanisms for MI remain largely unknown. SIRT1, one of highly conserved NAD-dependent class III deacetylases, has been involved in several cellular processes and implicated in human diseases. SIRT1is involved in cell survival and differentiation, genomic stability, transcription, metabolism, stress response and aging. Clinically, SIRT1has been implicated in inflammation, obesity, type2diabetes, cardiovascular diseases, neurodegenerative disease and cancer. Autophagy is one of major cellular degradative pathways, which plays important roles in lipid metabolism. SIRT1has been shown to induce autophagy by deacetylating autophagy-related (ATG) proteins (ATG5and ATG7) and forkhead box O transcription factors (FOXOs). In addition, SIRT1also regulates endothelial angiogenesis and atherosclerosis. Recent studies have shown that SIRT1deacetylates autophagy-related genes, and the expressions of autophagic genes are altered in MI patients. Accordingly, we hypothesized that SIRT1may be linked to the MI pathogenesis.Objective1) Investigating the relation between the variants of SIRT1gene promoter and myocardial infarction by analyzing the genetic analysis of SIRT1promoter in myocardial infarction patients.2) Detecting the SIRT1function and identifing its function changes by determinating the luciferase reporter gene vector series of pGL3. It could provide a theoretical basis for predicting the risk of myocardial infarction at the genetic level and open the door for novel treatment and prevention strategies for myocardial infarction.Methods1) Genomic DNAs were extracted from peripheral leukocytes. SIRT1gene promoter sequence was amplified by using polymerase chain reaction. The SIRT1gene promoter was analyzed by direct sequencing.2) The SIRT1mutant gene was amplified with the pMDR19-T vector and then inserted into the pGL3-Basic Vector. The pGL3-Basic Vector with SIRT1mutant gene and PRL-TK vector together were contransfected to HEK-293. The amount of firefly luciferase and renilla luciferase were measured, and then its ratio was calculated, in order to observing the functional change of SIRT1gene promoter.Results1) The results showed that six single-nucleotide polymorphisms and14sequence variants were identified. Among these, five novel heterozygous variants (g.69643743Ins, g.69643840Ins, g.69643903G>C, g.69644235G>C and g.69644353G>T) and one single-nucleotide polymorphism (rs35706870) were identified in MI patients, but in none of controls. Moreover, five novel heterozygous variants (g.69643672G>A, g.69644226C＞T, g.69644278A>G, g.69644408G>A and g.69644408G>T) were only found in controls. The rest variants were found in MI patients and controls with similar frequencies.2) The difference between the SIRT1mutant gene in myocardial infarction and normal subjects was statistically significant (p<0.05). However, comparing to the normal SIRT1, the SIRT1mutant genes in healthy control was not statistically significant (p>0.05).3) The function of SIRT1gene is changed in myocardial infarction patients, compared to the normal control; the viariation of SIRT1can be weakened or be enhanced.ConclusionTaken together, the variants identified in MI patients may alter the transcriptional activities of SIRT1gene promoter, which may change SIRT1levels, contributing to the MI pathogenesis as a risk factor. |
PDF Full Text Request