AIM:To investigate whether melatonin can ameliorate acute myocardial infarction(AMI)by in⁃hibiting ferroptosis.METHODS:H9C2 cells were cultured in AnaeroPack system with low sugar and serum-free medium for 10 h to con...AIM:To investigate whether melatonin can ameliorate acute myocardial infarction(AMI)by in⁃hibiting ferroptosis.METHODS:H9C2 cells were cultured in AnaeroPack system with low sugar and serum-free medium for 10 h to construct a cell model of AMI.Then cells were treated with melatonin and ferroptosis inducer erastin.The cell activity,reactive oxygen species(ROS),lipid peroxidation,mitochondrial membrane potential(MMP),and ferroptosis related protein expression were detected.A rat model of AMI induced by isoprenaline(ISO)injection was established to evaluate the effects of melatonin,in which the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,iron ion and ferroptosis related protein expression were examined.RESULTS:Melatonin decreased the oxidative stress,lipid peroxidation and expression of ferroptosis protein in cardiomyocytes induced by hypoxia,but these effects could be impeded by the ferroptosis inducer erastin.Furthermore,in vivo experiments,we also found that melatonin im⁃proved the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,and alleviated iron ion accu⁃mulation and ferroptosis.CONCLUSION:The cardioprotective effects of melatonin in AMI are associated with the inhi⁃bition of ferroptosis.展开更多
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-di...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 NLRP3 expression 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.展开更多
The integrity and function dysfunction of the blood brain barrier(BBB)is considered to be an early event in the pathogenesis of a variety of neurological diseases in old patients and dysfunction of BBB could be induce...The integrity and function dysfunction of the blood brain barrier(BBB)is considered to be an early event in the pathogenesis of a variety of neurological diseases in old patients and dysfunction of BBB could be induced bycommon stress that old people often face,such as sepsis during which lipopolysaccharide(LPS)is released into circulation and BBB is damaged.Since decreased melatonin level had been shown in the serum and brain of old people and mice,we aim to investigate whether supplement with melatonin could alleviate LPSinduced BBB damage in old mice.Mice(24-28 months old)received one week melatonin(10 mg·kg-1·d-1,intraperitoneally,ip)or saline before challenge with LPS(1 mg·kg-1,ip).Evan′s blue(EB)and immunoglobulin G(Ig G)leakage were used to assess the BBB permeability.Immunofluoresence and Western blotting were used to detect the protein expression and distribution.Our results showed that LPS significantly increased BBB permeability in old mice accompanied by tight junction protein occludin and claudin-5 degradation,inhibition of AMP-activated protein kinase(AMPK)activation and increase of gp91phox protein expression.Interestingly,one week of melatonin treatment significantly decreased LPS-induced BBB hyperpermeability,activated AMPK and inhibited gp91phox expression upregualtion.Moreover,activation of AMPK by metformin significantly inhibited LPS-induced gp91phox expression upregualtion in endothelial cells.Taken together,our findings demonstrate that melatonin alleviates LPS-impaired integrity of BBB by activation of AMPK and inhibition of gp91phox expression in old mice.展开更多
基金Supported by Guangdong Medical Research Foundation(No.A2024382)Guangdong Provincial Bureau of Traditional Chinese Medicine research project(No.20231321)Scientific Research Start Plan of Shunde Hospital,Southern Medical University(No.SRSP2022012,No.SRSP2022016)。
文摘AIM:To investigate whether melatonin can ameliorate acute myocardial infarction(AMI)by in⁃hibiting ferroptosis.METHODS:H9C2 cells were cultured in AnaeroPack system with low sugar and serum-free medium for 10 h to construct a cell model of AMI.Then cells were treated with melatonin and ferroptosis inducer erastin.The cell activity,reactive oxygen species(ROS),lipid peroxidation,mitochondrial membrane potential(MMP),and ferroptosis related protein expression were detected.A rat model of AMI induced by isoprenaline(ISO)injection was established to evaluate the effects of melatonin,in which the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,iron ion and ferroptosis related protein expression were examined.RESULTS:Melatonin decreased the oxidative stress,lipid peroxidation and expression of ferroptosis protein in cardiomyocytes induced by hypoxia,but these effects could be impeded by the ferroptosis inducer erastin.Furthermore,in vivo experiments,we also found that melatonin im⁃proved the myocardial infarction size,cardiac injury,pathological changes,oxidative stress,and alleviated iron ion accu⁃mulation and ferroptosis.CONCLUSION:The cardioprotective effects of melatonin in AMI are associated with the inhi⁃bition of ferroptosis.
基金supported by National Natural Science Foundation of China(8157039981270042)
文摘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 NLRP3 expression 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.
文摘The integrity and function dysfunction of the blood brain barrier(BBB)is considered to be an early event in the pathogenesis of a variety of neurological diseases in old patients and dysfunction of BBB could be induced bycommon stress that old people often face,such as sepsis during which lipopolysaccharide(LPS)is released into circulation and BBB is damaged.Since decreased melatonin level had been shown in the serum and brain of old people and mice,we aim to investigate whether supplement with melatonin could alleviate LPSinduced BBB damage in old mice.Mice(24-28 months old)received one week melatonin(10 mg·kg-1·d-1,intraperitoneally,ip)or saline before challenge with LPS(1 mg·kg-1,ip).Evan′s blue(EB)and immunoglobulin G(Ig G)leakage were used to assess the BBB permeability.Immunofluoresence and Western blotting were used to detect the protein expression and distribution.Our results showed that LPS significantly increased BBB permeability in old mice accompanied by tight junction protein occludin and claudin-5 degradation,inhibition of AMP-activated protein kinase(AMPK)activation and increase of gp91phox protein expression.Interestingly,one week of melatonin treatment significantly decreased LPS-induced BBB hyperpermeability,activated AMPK and inhibited gp91phox expression upregualtion.Moreover,activation of AMPK by metformin significantly inhibited LPS-induced gp91phox expression upregualtion in endothelial cells.Taken together,our findings demonstrate that melatonin alleviates LPS-impaired integrity of BBB by activation of AMPK and inhibition of gp91phox expression in old mice.
