| Parkinson’s disease is a very common neurodegenerative disease relating dopaminergic neurons degeneration,and intracellular α-synuclin(α-syn)protein expression is significantly increased,gathering to form inclusion-Lewy body.In the midbrain substantia nigra of Parkinson’s patients,the level of autophagy increased and the expression of autophagy-related protein also increased,leading to autophagic apoptosis of neurons,dopaminergic neuron damage and degeneration.β-synuclin(β-syn),as a homologues of α-syn,has been confirmed to inhibit α-syn protein aggregation in vitro cell experiments.What roles and through which way of β-syn to protect the neurons in vivo,are the themes in this project.In the study,first we constructed the MPTP Parkinsonian chronic mouse model.The wild type β-syn plasmid was obtained by PCR-related experiment,and the β-syn plasmid was packaged into human adenovirus with GFP tag to make β-syn and GFP protein fusion,then the virus infected neurons of the midbrain substantia nigra in the MPTP mice through the microinjection.Parkinson’s disease is often accompanied by the decline of motor abilities.Therefore,behavior is an important index to detect Parkinson’s disease.In this study,the behavioral indexes of MPTP mice were tested by footsteps and Rota Rode.The results showed that MPTP resulted in a decrease in the step distance of the mice and a shortening of the time on the Rota Rode.Compared with the control virus group,the footsteps and the time on the Rota Rod increased in the virus group containing β-syn.That is,β-syn can improve the MPTP-induced behavioral decline.The results of immunofluorescence staining showed that the virus could successfully infect neurons in the injection site and could be projected into other brain regions such as hippocampus and striatum.The overexpression of β-syn in the brain was observed by immunofluorescence staining.Immunohistochemistry and immunoblotting were used to detect the expression of α-syn protein.MPTP could lead to abnormal overexpression of α-syn protein and increase the degree of aggregation,on which β-syn overexpression produced an inhibitory effect.Immunostaining and immunoblotting results showed that MPTP could lead to the degradation and reduction of dopaminergic neurons,the decrease of neuronal discharges in the substantia nigra.However,β-syn producted a protective effect on the dopaminergic neurons and promoted the neuron to increase frequency of discharge.The results showed that MPTP could increase the expression of autophagy-related protein and increase the degree of autophagy.Compared with the control virus group,autophagy-related protein decreased,and autophagy was inhibited in the group injected virus content β-syn.In the autophagy study,autophagy has been found to be affected by a variety of factors and a variety of signal paths.The mTOR signal pathway was studied by immunoblot and statistical,displaying that MPTP promoted the autophagy-related factors mTOR,p-4EBP1 expression to increase.Compared with the control virus group,the expression of mTOR and p-4EBP1 was decreased and the expression of inhibitory factor p-mTOR was increased,indicating that β-syn could inhibit the role of mTOR pathway in autophagy,and reduce MPTP-induced autophagic apoptotic cells.In conclusion,β-syn can reduce the expression and abnormal aggregation of α-syn caused by MPTP,reduce the damage and apoptosis of dopaminergic neurons,play a role in promoting the neuronal discharge and reduce the degree of autophagy in the substantia nigra brain area by inhibiting the mTOR pathway to promote autophagy.Thus,β-syn plays a very important role in the study of Parkinson’s disease and brings new targets and directions to the treatment of Parkinson’s disease. |
