Methamphetamine Mediates Apoptosis Of Vascular Smooth Muscle Cells Through Chop-related Endoplasmic Reticulum Stress Pathway

Methamphetamine(METH)is the most common abuse among amphetamine-type stimulants.Because of its simple production,low price,easy access,long-lasting effect and strong excitability,methamphetamine has become one of the most serious new drugs.The cardiovascular toxicity of methamphetamine has been widely concerned.Cardiovascular complications such as acute coronary syndrome,hypertension,aortic dissection,and pulmonary hypertension are associated with methamphetamine abuse.Smooth muscle cells constitute an important component of the blood vessel wall,and its function and structure changes are the cytopathological basis of the above diseases.It is suspected that METH may cause damage to vascular smooth muscle cells,which in turn causes cardiovascular damage.Previous studies in our laboratory found that METH induced apoptosis in vascular endothelial cells via mitochondrial Nuprl-Chop/P53-PUMA/Beclinl pathway.The expression of apoptosis maker gene of vascular smooth muscle cells is rising in amphetamine-induced aortic aneurysm and aortic dissection aneurysm models,so we suspect that METH causes apoptosis in vascular smooth muscle cells through a similar molecular pathway.Endoplasmic reticulum stress(ERS)is an important intracellular apoptosis signal pathway studied by our group.CHOP plays a key role in regulating ERS-mediated apoptosis,and external factors.When ERS is induced,it is regulated by related transcription factors,up-regulates its protein expression level,and then induces apoptosis by activating its downstream apoptosis-related gene expression.Therefore,Chop-related endoplasmic reticulum stress pathway is the focus of this topic.AimsTo explore the molecular pathway of CHOP-related endoplasmic reticulum stress pathway mediated apoptosis of smooth muscle cells,provide a theoretical basis for METH-induced cardiovascular toxicity damage regulation mechanism,and provide strategies and possible targets for METH cardiovascular system injury research and intervention therapy.MethodsThis experiment established a model of METH exposure in vivo and in vitro,interfering with the expression of the target gene CHOP by endoplasmic reticulum inhibitors 4-PBA and RNAi,and then using Western Blot,flow cytometry,TUNEL staining,co-immunoprecipitation and other techniques to detect related protein in endoplasmic stress and apoptosis-related pathways,to explored the role of CHOP-mediated signaling pathway in METH-induced smooth muscle cell injury.ResultPart 1 Methamphetamine induces apoptosis and endoplasmic reticulum stress in vascular smooth muscle1.METH can induce the expression of cleaved PARP and cleaved caspase-3 protein in the in vivo and in vitro experiments,and induce apoptosis of vascular smooth muscle cells.2.METH can induce the expression of stress-related factors XBP-1,eIF2a,P-eIF2?,ATF-6 and ATF-6 ? protein in vivo and in vitro,and then endoplasmic reticulum stress.3.The endogenous stress signaling pathway is involved in METH-induced apoptosis of vascular smooth muscle cells.4.CHOP-related pathways are involved in endoplasmic reticulum stress-mediated METH-induced apoptosis of vascular smooth muscle cells.Part 2 The mechanism of action of Chop in vascular smooth muscle apoptosis induced by methamphetamine and endoplasmic reticulum stress1.METH activates vascular AKT-FOXO3a signaling pathway by activating endoplasmic reticulum stress,and decreases the expression levels of phosphorylated AKT and FOXO3a.2.METH inhibits the phosphorylation level of AKT by CHOP-mediated endoplasmic reticulum stress pathway,which increases the dephosphorylation level of FOXO3a,and increases the dephosphorylation of FOXO3a into the nucleus.On the other hand,METH induces an increase in CHOP entry into the nucleus and interacts with FOXO3a in the nucleus.3.METH enhances the interaction between FOXO3a and CHOP in the nucleus,thereby activating the mitochondrial apoptotic pathway to increase the expression of proapoptotic molecules PUMA,BIM,Bax,and inhibiting the expression of anti-apoptotic factor Bcl2,thereby increasing vascular apoptosis.ConclusionCHOP-related endoplasmic reticulum stress pathway plays a key regulatory role in METH-induced vascular smooth muscle cell apoptosis,providing strategies and possible targets for the study and intervention of METH cardiovascular system injury.