| BackgroundNeurodegenerative disease(NDD)is a group of diseases caused by neuron degeneration and death,which is closely related to aging.With the development of population aging,the incidence rate of neurodegenerative diseases is sharply increasing.Neurodegenerative diseases have become an important social and medical problem,causing a heavy burden to patients,families and society.Alzheimer's disease and Parkinson's disease are the first two most common neurodegenerative diseases.The existing treatment may help to alleviate the symptoms related to the disease,but it is not able currently to completely cure or reverse the progress of the disease.Therefore,it is of great significance to study the pathogenesis and therapeutic target.Carboxy1 terminus of the Hsp70 interacting protein(CHIP)is a protein encoded by STUB1 gene,which is widely expressed in brain,skeletal muscle,testis,heart and other tissues.CHIP containing the function of assisting chaperone and E3 ubiquitin ligase is a critical element in protein quality control system.CHIP could regulate the process of neuron energy production and redox,and increase the co-localization with mitochondria under stress,which also plays an important role in energy metabolism.CHIP involved in many neurodegenerative diseases.The mutation of CHIP itself can cause hereditary ataxia,accompanied by cognitive dysfunction and gonadal hypoplasia;the rats with point mutation of CHIP show obvious cognitive decline,in which the pathological results show that neurons in hippocampus are lost,and proteomic analysis shows that the level of CHIP in brain tissue of this model decreases,while Tau,PDE9A and other proteins related to Alzheimer's disease are markedly elevated.With the development of age and symptoms,the level of CHIP protein in brain decreased gradually.Therefore,up-regulation of CHIP expression may play a protective role in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.Adeno-associated virus(AAV)is a common vector in gene therapy,which has the characteristics of high safety and low immunogenicity,and can mediate the long-term expression of foreign genes.Different serotypes of AAV have different tissue affinity and expression efficiency.Due to the existence of blood-brain barrier,the carrier is difficult to enter the central nervous system through blood circulation.AAV/BBB is a new serotype that can penetrate the blood-brain barrier.The use of AAV/BBB to mediate the overexpression of CHIP protein in rat brain can effectively improve the behavioral and pathological damage of experimental cerebral hemorrhage rats,but it has not been reported in neurodegenerative diseases.In this study,in order to explore the protective effects of CHIP on Alzheimer's disease and Parkinson's disease,we used AAV/BBB to mediate the overexpression of CHIP in APPswe/PS1?E9 mice model of Alzheimer's disease and MPTP-lesioned mice model of Parkinson's disease.And the effects of CHIP overexpression on the behavior,pathology and related proteins of these two animal models were detected.Objective1.Using AAV vector to mediate the overexpression of CHIP in the mouse model of Alzheimer's disease,and further detected the effects of CHIP on the behavior,histopathology and protein expression of the mouse model of Alzheimer's disease.2.Using AAV vector to mediate the overexpression of CHIP in wild-type mice.MPTP was used to construct the animal model of acute Parkinson's disease,and the effect of CHIP on the expression level of behavioral and histopathological proteins in Parkinson's disease mice were detected.Methods1.AAV-mediated CHIP overexpression was performed in mouse brain through tail vein injection.2.The behavioral changes of APPswe/PS1?E9 mice were detected by nesting test and Morris water maze test.The behavioral changes of MPTP-induced acute Parkinson's disease mice were detected by pole test,rotarod test and open field test.3.The histopathological changes of the two animal models were detected by immunofluorescence,immunohistochemistry and Golgi staining,and the levels of mRNA and protein expression were detected by rt-PCR and Western Blot.Results1.Overexpressed CHIP was performed in brain of APPswe/PS1?E9 mice by tail vein injection of AAV/BBB vector virus.2.In behavioral experiments,CHIP overexpression improved the nesting ability of APPswe/PS1?E9 mice,shortened the latency of Morris water maze place navigation test,and increased the number of times crossing the platform in spatial probe Test.3.CHIP overexpression reduced the number of amyloid plaques in the cortex and hippocampus of APPswe/PS1?E9 mice,and decreased the levels of A?,Tau protein and phosphorylated Tau protein.4.CHIP overexpression inhibited the level of ?-secretase BACE 1,but had no significant effect on ?-secretase ADAM10,?-secretase PS1,or A? degrading enzyme,such as IDE and NEP.5.CHIP overexpressed in brain tissue of wild-type mice by tail vein injection of AAV/BBB vector virus,and mice showed Parkinson-like manifestations after Subsequently intraperitoneal inj ection of MPTP.6.Overexpression of CHIP shortened the time spent in pole test,prolonged the latency of rotarod test,and increased spontaneous activity in open field test of acute MPTP-lesioned mouse model of Parkinson's disease,which did not affect the behavioral performance of wild-type mice,7.CHIP overexpression improved MPTP-induced dopaminergic neuron death and TH protein reduction in the substantia nigra region of the midbrain8.CHIP overexpression inhibited MPTP-induced elevation of DRP1,a critical mitochondrial division-related protein in the substantia nigra and striatum.Conclusion1.CHIP overexpression ameliorated the behavior of APPswe/PS1?E9 mice,improved Alzheimer's disease-related protein and histopathology.CHIP had protective effect on mouse model of Alzheimer's disease.2.Overexpression of CHIP improved the behavioral dysfunction of MPTP-lesioned mice,reduced the damage of dopaminergic neurons,and inhibited the increase of DRP1 induced by MPTP.CHIP played a protective role on acute MPTP-lesioned mouse model of Parkinson's disease. |
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