Effect And Mechanism Of SULT2B1b On Proliferation And Inflammation Of Macrophage Induced By Ox-LDL

BackgroundCoronary artery disease(CAD)is a major disease that seriously endangers human health.Studies have confirmed that dyslipidemia and inflammatory immune response are the main etiology of arteriosclerosis(AS).Macrophage which is important immune cell plays an important role in lipid metabolism and vascular inflammatory immune response.In the process of arteriosclerosis formation,macrophages are activated by some risk factors such as oxidized low-density lipoprotein(ox-LDL),and after phagocytosing ox-LDL,they transform into foam cells to release numerous pro-inflammatory and inflammatory factors and stimulate self-proliferation which promoting the progression of AS.As Lipid-lowering therapy which is most useful therapy for CAD is can only bring a 30%reduction in major cardiovascular events(MACE),it is highly desirable to find out some new therapies to reduce residual risk.As the inflammatory response of macrophages plays an important role in the formation and development of AS,the inflammatory response of macrophages is expected to become a new target for the treatment of AS.Sulfotransferase family cytosolic 2B member 1(SULT2B1b)is an important cholesterol sulfotransferase that is closely related to lipid metabolism.In our previous study,we found that low expression of SULT2B1b can promotes the expression of liver X receptor-?(LXR-?)in lymphocytes,which drives an increased rate of cholesterol efflux and a decrease in intracellular cholesterol content.And we also found that both mRNA and protein levels of SULT2B1b were significantly increased in lymphocytes from patients with acute myocardial infarction(AMI)compared the patients without CAD.These results suggest that the expression level of sult2blb in lymphocytes may affect the progression of AS by regulating the inflammatory response.However,the inflammatory effects and mechanisms of SULT2B1b on macrophages are not well defined.Recent studies have found that small molecular RNAs(miRNAs)can negatively regulate biological gene expression through translational repression or degradation of mRNA,and have regulatory effects on blood lipid metabolism and macrophages inflammatory responses.ObjectivesThis study was to investigate the effect of low expression SULT2B1b on the proliferation and inflammatory response of macrophages treated with ox-LDL,combined with the differential expression levels of miRNAs from macrophages,and find out the mechanism of low expression SULT2Blb on the inflammatory response of macrophages treated with ox-LDL which provide a new therapeutic direction for AS.MethodsRAW264.7 cells were stimulated with ox-LDL after transfection with adenovirus low expressing of SULT2Blb(ad-shSULT2Blb)as well as control adenovirus(AD GFP).The RT-qPCR,Western Blotting,CCK-8,EdU,immunofluorescence,miRNA sequencing,online bioinformatics database prediction,dual luciferase assay,CO immunoprecipitation,electrophoretic mobility shift assay(EMSA)were performed to detect the proliferation of RAW264.7 cells,the expression of IL-6 and TNF-?.And we used these methods to find the miRNA who was differentially expressed acted as downstream factor of SULT2B1b.We also clarified the specific mechanism by which low expression of SULT2B1b affected the proliferation and inflammatory response of macrophages stimulated ox-LDL.Res?ltsWe found that:1.Low expression of SULT2B1b not only inhibited the proliferation of RAW264.7 cells treated by ox-LDL,but also reduced the expression of IL-6 and TNF-?;2.miRNA sequencing results showed that low expression of SULT2B1b increase the expression of miR-148a-3p,and miR-148a-3p analogues could enhance the SULT2Blb's inhibition on the proliferation of RAW264.7 cells and the expression of IL-6 and TNF-?;meanwhile miR-148a-3p inhibitor can weaken the above inhibition function;3.IKBKB is the direct target gene of miR-148a-3p and is negatively regulated.Low expression of SULT2B1b can promoted the expression of miR-148a-3p which will regulates the expression of I?B,IKK? and p-P65 by acting on IKBKB site,inhibit the NF-?B pathway induced by ox-LDL.ConclusionDecreased SULT2B1b expression can reduce the inflammatory response and proliferation of ox-LDL-treated macrophages by upregulating miR-148a-3p expression which negatively regulate IKBKB.Decreased SULT2B1b expression can also promote the expression of I?B,reduce the expression of IKK? and p-P65,and inhibit the NF-?B pathway activated by ox-LDL.Therefore,reducing the expression of SULT2Blb in macrophages and inhibiting the inflammatory response of macrophages may be a new target of treatment of AS.