Melatonin prevents endothelial cell pyroptosis via regulation of long noncoding RNA MEG3/miR-223/NLRP3 axis / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the anti-pyroptotic effects of melatonin in atherosclerotic endothelium and to elucidate the potential mechanisms.METHODS ApoE-/-mice were randomly divid-ed into four groups (n=8) the normal-diet group (ND), the normal-diet group treated with melatonin (10 mg·kg-1)(ND+MLT),the high-fat-diet group(HFD),and the high-fat-diet group treated with melatonin (HFD+MLT).After 12 weeks,the expression levels of pyroptosis related genes including NLRP3,ASC, cleaved-caspase 1,GSDMD-N,IL-1β and IL-18 were examined in aortic endothelium by Western blotting, qRT-PCR and immunofluorescent staining.Besides,levels of MEG3 and miR-223 were also tested by qRT-PCR.The interaction between MEG3 and miR-223 was detected by luciferase assay.For in vitro study,human aortic endothelial cells(HAECs)were transiently transfected with miR-223 mimic,miR-223 inhibitor (AMO-223), MEG3-overexpressing plasmid or negative controls. After 6 h of transfection, the medium was replaced by fresh medium with or without ox-LDL(25 μg·mL-1)for 24 h and then treated with or without melatonin (10 μmol·L-1) for 48 h. Cell pyroptosis was evaluated by Hoechst 33342/PI staining and differentially expressed pyroptosis related genes. RESULTS Melatonin markedly reduced the atherosclerotic plaque in aorta of ApoE-/- mice. Meanwhile, melatonin also attenuated the expression NLRP3, ASC, cleaved-caspase1, NF-κB/GSDMD, GSDMD-N termini, IL-1β, and IL-18 in aortic endo-thelium.Consistent anti-pyroptotic effects were also observed in ox-LDL-treated HAECs.We found that lncRNAMEG3 enhanced pyroptosis in HAECs. Moreover, MEG3 acted as an endogenous sponge by sequence complementarity to suppress the function of miR-223 and to increase NLRP3expression and enhance endothelial cell pyroptosis. Furthermore, knockdown of miR-223 blocked the anti-pyroptotic actions of melatonin in ox-LDL-treated HAECs. CONCLUSION Melatonin prevents endothelial cell pyroptosis via MEG3/miR-223/NLRP3 axis in atherosclerosis and therefore melatonin replacement might be considered a new strategy for protecting endothelium against pyroptosis thereby for the treat-ment of atherosclerosis associated with pyroptosis.