The Effect Of METTL3 Mediated M6A Modification On Apoptosis Of Macrophagederived Foam Cell And The Progression Of Atherosclerosis

[Background and Objective]:Atherosclerosis(As)is a chronic inflammatory disease,and vascular inflammation is considered to be the key regulatory in the development of As.As the main effector cells of the immune system,macrophages accumulate on the walls of damaged blood vessels,and take up a large amount of lipids to form foam cells.At the same time,a large number of macrophages,T lymphocytes and other inflammatory cells were recruited furtherly.These cells can release various inflammatory mediators to promote the formation of foam cells,forming a vicious cycle that exacerbates the development of As.The related regulatory mechanism of macrophages is an important part of the research on the prevention and treatment of As diseases.In recent years,RNA modification has attracted much attention as an emerging research field.Among them,N6-methyladenosine(m6A)which is the most abundant modification on mRNA plays an important role in regulating gene expression and other life processes.The m6 A modification refers to the methylation modification on the N atom at position 6 of adenine.Methyltransferase like 3(METTL3)is the core component of the m6 A methyltransferase complex and is widely distributed in humans.Recent studies have found that overexpression of METTL3 can modulate lipid levels and reduce intracellular triglycerides.In addition,METTL3 has been proved to play an important role in regulating myocardial remodeling.The role of METTL3 and m6 A modification in the cardiovascular field has been revealed gradually.In order to confirm the connection between METTL3 and As,our team have found that METTL3 expresses widely in plaque areas in atherosclerotic plaques;and the expression of METTL3 increases significantly in the foam cells which is induced by human myeloid leukemia mononuclear cells(THP-1)derived monocytes with oxLDL(ox-LDL)treatment.The above results suggest that METTL3-mediated m6 A modification may be a new regulatory pathway for the development of atherosclerotic diseases,but its specific role and mechanism remain to be elucidated.Therefore,we use METTL3 as the key point to explore the effects and potential mechanisms of METTL3-mediated m6 A modification of foam cells.[Methods]:Taking human carotid atherosclerotic plaque tissue as paraffin section,and detect the expression of METTL3 in atherosclerotic plaque tissue by immunohistochemical staining(IHC);establishing a mouse hyperlipidemia model,then taking model mouse heart to make frozen sections of aortic valve,and atherosclerotic plaques is detected by oil red O staining and HE staining.At the same time,the expression of METTL3 in the plaques with IHC;THP-1monocytes are induced by phorbol myristate acetate(PMA)to form macrophages,and then treated with ox-LDL to construct a foam cell model.Using Western Blot(WB)and EpiQuik m6 A RNA methylation quantification kit to detect METTL3 and overall m6 A levels in foam cells,and completing m6 A highthroughput sequencing,using IGV,KEGG and other data analysis to screen for significant m6 A changes and target genes in foam cells.[Results] : METTL3 expresses widely in human atherosclerotic plaques and mouse heart plaques.After THP-1 is induced into foam cell,METTL3 and overall m6 A modification expression increases.The m6 A sequencing results shows that the m6 A modification level of the apoptotic pathway significantly changes.After interfering with METTL3 in foam cells,the apoptosis rate increases,the expression of BAX protein and mRNA rises,and significant m6 A peak shows on the BAX mRNA.[Conclusion]: 1.METTL3-mediated m6 A modification participates in the regulation of As;2.In the early stage of As,macrophages are transformed into foam cells,METTL3 may inhibit m6 A modification on BAX mRNA,inhibit apoptosis,and promote the development of As plaques.