Studies On The Effects Of MiR-320a On The Occurrence And Progress Of Atherosclerosis

Atherosclerotic cardiovascular disease(CVD)is a chronic disease and the pathogenesis of atherosclerosis(As)is a multistage process involving multiple genes and molecular regulatory pathways.However,despite ongoing research regarding the mechanisms in As,the intracellular molecular events in the initiation and the progression of cardiovascular diseases have not yet been fully elucidated.The recent emergence of microRNAs(miRNAs)as critical fine tuners of many biological processes has provided novel molecular insights into their impact on the process of atherosclerosis.In our previous study,we found that expression of miR-320a was up-regulated in the serum of As patients.But the roles of miR-320a implicated in regulating critical aspects of atherosclerosis are still unclear.Objectives:(1)Quantitative real-time PCR(qRT-PCR)was used to examine the expression of miR-320a in As group and the normal control group.(2)To investigate how miR-320a contributes to the key links in the progress of atherosclerosis including cytokines secretion,cholesterol efflux and cellular cholesterol content in foam cell model.(3)To further testify the influence of miR-320a in the occurance and development of atherosclerosis in animal model.(4)To evaluate miR-320a’s clinical relevance to the atherosclerosis development and to provide experimental evidence for atherosclerotic cardiovascular disease treatment.Methods:(1)Total RNA was extracted from the serum of 92 As patients and 100 normal people,as well as the foam cell model.Quantitative real-time PCR(qRT-PCR)was used to determine the expression of miR-320a and to verify the ealy results of miRNA profiling microarray analysis.(2)Bioinformatics Analysis was applied to predict the target gene of miR-320a and luciferase reproter assay system was used to verify the targeting effect.(3)Liposome transfection,si-RNA technology and ABCG1 plasmids was used to up/down-regulate the expression of miR-320a and its target gene—ABCG1,then the functional analyses including cytokines secretion,cholesterol efflux and cellular cholesterol content was applied to detect the function of miR-320a.(4)Up-/down-regulated expression of miR-320a was achieved by lenti-virus transfection via tail vein and further in vitro analyses verified the influence of miR-320a on As plaque.Results:(1)qRT-PCR results showed that the expression of miR-320a was significantly higher in CVD patients compared with normal control group and its expression in foam cell was obviously increased.(2)ABCGI was the target gene predicted by Bioinformatics Analysis and the results of luciferase reproter assay system and Western Blot verified that miR-320a could negatively regulated the expression of ABCGI.(3)MiR-320a could down regulate the expression of ABCG1,and induced the secretion of cytokines and cellular cholesterol content,while the cholesterol efflux was inhibited.(4)Over expression of miR-320a in As mouse model could accelerate the process of As while down-regulate its expression led to supress atherosclerotic plaque formation.Conclusions:MiR-320a could negatively regulate the expression of ABCG1 and was the important regulatory factor in the development of As via induced the cellular cholesterol content and cytokines secretion.MiR-320a may the novel therapy target for atherosclerosis.