Correlation Between Methamphetamine Induced α-synuclein Aggregation And Memory Impairment And The Mechanism Of CHMP2B On Its Expression

Objective:Methamphetamine has become the most widely abused neural activity agonist in China,and it has variety damage on human health.Multiple mechanisms have been revealed to be involved in mediating methamphetamineinduced neurotoxicity,thereby causing neurodegeneration.Meanwhile,α-synuclein,as the pathogenic protein of various neurodegenerative diseases,plays an important role in methamphetamine-mediated neurotoxicity.Because of this,this study intends to use a rodent model of chronic methamphetamine misuse and detect the level of αsynuclein and to observe the changes in learning and memory through behavioral experiments,therefore to investigate the pathological changes of the hippocampus,which has related to memory function,and to explore the correlation between α-syn and methamphetamine-induced memory impairment.In the meantime,cell model and rodent model were used to investigate whether the autophagosome fusion-related protein CHMP2B was involved in the degradation of hippocampal α-synuclein induced by methamphetamine,leading to reveal the possible molecular mechanisms and providing potential targets for further detoxification therapy.Methods:(1)A 14-day gradually escalating METH poisoning rodent model was established.Novel object recognition and Morris water maze experiments were tested to assess the memory function of mice.(2)Brain tissue samples were collected,and immunohistochemical staining was used to observe the pathological changes of methamphetamine in the hippocampus;Western Blot was used to detect the levels of α-synuclein,LC3,P62,and levels of CHMP2B,one of the ESCRT-Ⅲ complex members in the mouse hippocampus.(3)The methamphetamine cytotoxic model was established,and the primary neurons of C57 mice were cultured and treated with 0.2 mmol/L methamphetamine for 24 hours.(4)The expression changes of LC3B,P62 and α-synuclein were detected by immunofluorescence method;the level of CHMP2B,a member of ESCRT-Ⅲcomplex,was detected by Western Blot.(5)The primary hippocampal neurons were transfected with lentivirus to overexpress CHMP2B,and the levels of α-synuclein and autophagy were detected.Results:(1)Compared with the Control group,mice with chronic METH treatment showed a decrease in discrimination index(DI)in the novel object recognition experiment,an increase in escape latency in the water maze experiment,and a decrease in the number of crossing the target platform.(2)The level of α-syn in the hippocampus was significantly increased after the administration of METH,and the levels of α-syn of the model group exposure was negatively correlated with DI.(3)In both vitro and in vivo experiments,under the effect of METH,the levels of LC3B and P62 increased;the level of CHMP2B was decreased while the level ofα-syn was increased.(4)In vitro experiments,after the overexpression of CHMP2B lentivirus transfected primary neurons,the autophagy of METH-treated neuron was enhanced,and the accumulation of α-syn was alleviated.Conclusion:Increased α-syn induced by METH is negatively correlated with learning and memory levels,and the exogenous increase of CHMP2B,an important protein of autophagy-lysosomal fusion,has a certain protective effect on the abnormal expression of α-syn.