Epigenetic Variation Of FT3 Level In Patients With Coronary Heart Disease And Its Influence On Lipid Metabolism

Coronary artery disease(CAD)is one of the main causes of human death,and its morbidity and mortality are increasing year by year.Risk factors such as thyroid hormone imbalance and dyslipidemia will lead to an increasing burden of coronary heart disease.It can be seen that it is particularly important to accurately assess the prognostic value of thyroid hormones for coronary heart disease and to clarify the lipid metabolism mechanism involved.Therefore,this study firstly evaluated the relationship between FT3 level and prognosis in patients with coronary heart disease in a large-scale coronary follow-up cohort in a single center,and clarified the correlation between FT3 concentration and blood lipid profile.Further,through an epigenome-wide association study of FT3 levels in Chinese patients with coronary heart disease,we found CpG loci that affect FT3 levels in the Chinese population,and further analyzed the relationship between FT3 levels in patients with coronary heart disease and clinical endpoints and events of candidate loci.Mediating effects in blood lipids.Finally,the role of T3 combined with 5-Aza-CdR in lipid accumulation in human hepatoma cells was investigated to explore the effect of T3 and genome-wide demethylation on lipid metabolism.First,in 5104 patients with coronary heart disease,it was observed that there were significant differences in blood lipid levels between the low FT3 group and the normal group.The levels of lipoprotein A and lipoprotein A were significantly positively and negatively correlated,respectively.Next,it was also confirmed that low levels of FT3 were independent predictors associated with increased risk of death and MACE in patients with CAD.In addition,an epigenome-wide association study based on two Chinese coronary heart disease patient cohorts showed that FT3-related DNA methylation variant genes were mainly enriched in metabolic pathways and involved in molecular functions of protein binding.There were significant associations between cg23597162(JAZF1)and cg02833127(SPATA4)and FT3 levels,and the cg02833127 hypomethylation level of SPATA4 gene was an independent risk factor for death and MACE risk in patients with coronary heart disease.Based on previous studies revealing that JAZF1 and SPATA4 play important roles in lipid metabolism,we analyzed the mediating effects of two FT3-related CpG sites on clinical prognosis and blood lipids,and found that methylation of cg02833127 could explain the 42.33%of the association between FT3 and death and 42.38%of the association between FT3 and MACE events,and the mediated proportion of cg02833127 in FT3 and blood lipid APOA levels was 29.62%,it can be seen that the methylation of cg02833127 can be used as a Important mediators of associations between FT3 and clinical endpoint events and changes in APOA levels.Finally,human hepatoma cells were treated with T3 combined with a DNA methyltransferase inhibitor,5-aza-2’-deoxycytidine(5-Aza-CdR),to further observe its effect on lipid accumulation in human hepatoma cells and Effects of lipid-related gene expression.The results of Oil Red O staining showed that T3 could reduce lipid accumulation,and 10 μM T3 had the most significant effect on inhibiting lipid droplets,while the addition of 5-Aza-CdR on the basis of 10μM T3 treatment could make the lipid droplets become more concentrated.Dependency decreases.The results of ELISA further confirmed that T3 combined with 5-Aza-CdR can reduce lipid accumulation,the TG content in cells was significantly reduced after 100μM T3 treatment,while the addition of 1 μM or 25μM of 5-Aza-CdR reversed the increase in APOA levels caused by increased T3 concentration in cells.Finally,RT-PCR results showed that different concentrations of T3 and 5-Aza-CdR could up-regulate C/Ebpβ,down-regulate the expression of PLIN1 and ATGL genes,and T3 and 5-Aza-CdR could synergistically inhibit the expression of JAZF1 and SPATA4 genes.In conclusion,this study found that FT3 is an important prognostic marker in CAD patients,clarified the association between methylation variation and FT3 levels from an epigenetic perspective,and revealed the role of DNA methylation between FT3 levels and dyslipidemia and clinical prognosis.In addition,the effect of T3 combined with 5-Aza-CdR on lipid metabolism in human hepatoma cells was also described.