Distribution and expression of anterior pharynx-defective-1 in mice central nervous system of APP/PS1 transgenic Alzheimer's disease model / 中华老年医学杂志

ObjectiveTo investigate the distribution and expression of y-secretase subunit (APH-1)in the central nervous system (CNS) of APP/PS1 double transgenic Alzheimer's disease (AD) adult mouse model,and to detect the expression difference of APH-1 in developmental brain between AD model mouse and wild-type littermates in order to further clarify the relationship between APH-1 and AD. MethodsOffspring bred by APP/PS1 double transgenic AD mice were genotyped.Immunohistochemical staining was used to detect APH-1 distribution and expression in the CNS of adult APP/PS1 double transgenic AD mouse model,in the brain of AD model mouse and its wild-type littermates on postnatal day 1,7,21 and 120.Results APH-1 was widely expressed in almost all regions of the CNS,especially in the cerebral cortex,hippocampus,olfactory bulb,hypothalamus,ventral striatum,caudate putamen,raphe magnus nucleus,cerebellum,brainstem and spinal cord of the adult APP/PS1 double transgenic mice.APH-1 expression was higher in the cortex of both AD and wild type mouse on postnatal day 1 than on postnatal day 7 and 21 with increased level of APH-1 protein in adult mouse brain.APH-1 expression in the brain of AD mice was higher than in its wild type littermates at any stage(P＜0.05).Conclusions Distribution of APH-1 is ubiquitous and region-dependent in the CNS.The different distribution and expression between APP/PS1 double transgenic mouse model and its wild type littermate indicate that APH-1 may be related to AD.

The effect of valproic acid on behavior and senile plaques in the male and female APP/PS1 double transgenic mouse model / 中华行为医学与脑科学杂志

Objective To investigate whether valproic acid (VPA) affect spatial learning memory and senile plaques in the APP/PS1 double transgenic AD mouse model of different gender. MethodsTwenty 3-month old APP/PS1 double transgenic AD mice,male and female mouse evenly,were randomly divided into VPA-treated and saline-treated groups ( 10 for each group). 30 mg· kg-1 · d-1 of VPA and the same amount of saline were peritoneally injected into mice for 4 weeks. Morris water maze was conducted to check the effect of VPA on the capability of spatial learning and memory of AD mouse model. Immunohistochemical staining was used to examine the effect of VPA on the morphological changes in the brains of mice. ResultsVisible platform test showed that VPA-treated and saline-treated mice had similar escape latency (P＞0.05) and path length (P＞0.05) ,the swimming speed between male and female mice had no difference (P＞0.05). Hidden platform test showed that VPA treated mice had a significantly shorter latency (P＜0.01) and path length (P＜0.01) to reach the platform compared with saline-treated mice. Meanwhile, both in VPA-treated and control groups, the male mice had a shorter correlation escape latency and path-length than female mice had(P＜0.05 ). Immuohistochemical staining showed that the number (11.23±3.78) of senile plaques (SP) in the cerebral cortex and hippocampus of VPA-treated male mice were notably decreased than that(28.17 ±3.46) in the control group ( t= 14.67, P＜0.01 ),furthermore,the number of SP in the cerebral cortex and hippocampus of VPA-treated male mice was significantly reduced,as compared with which (20.36 ±4.21)in the VPA-treated female mice(P＜0.05). ConclusionVPA can significantly lower formation of SP, and remarkably improve the capability of spatial learning and memory of APP/PS1 transgenic mice,which have gender difference.

The effect of proteasomal inhibitors on anterior pharynx decfective-1 expression in neuronal cells / 中华神经科杂志

Objectives To investigate whether degradation of anterior pharynx decfective-1(Aph-1) goes through proteasomal pathway or lysosomal pathway.Methods Various methods such as cell culture,Western blotting,pulse-chase metabolic labeling technique,double immunofluoresecnt staining,combined with proteasomal and lysosomal inhibition were used to check Aph-1 expression level in stable Aph-1-transfected or non-transfected neuronal(SH-SY5Y)cell line.Results Using Western blotting,treating the neuronal cells with proteasome specific inhibitors significantly increased the expression of both endogenous and exogenous Aph-1.The effect of the proteasome inhibitors on Aph-1 expression was dose-and time-dependent Lysosomal pathway was not involved in Aph-1 degradation. Pulse-chase metabolic labeling experiment showed that the turnover of newly-synthesized radiolabeled Aph-1 protein was blocked by Lactacystin.Double immunofluorescent staining revealed colocalization of Aph-1 and ubiquitin in the same cells.Conclusion Degradation of Aph-1 protein is mediated by proteasomal pathway in neuronal cells,and is not related to lysosomal pathway.Aph-1 protein is ubiquitinated before degradation.

Effect of proteasomal inhibitors on nicastrin expression in neuronal cells / 中国病理生理杂志

AIM: To explore the possibility that proteasome is involved in nicastrin(NCT) degradation and NCT is ubiquitinated before degradation.METHODS: Following the generation of NCT stable cell lines,the methods of Western blotting,pulse-chase metabolic labeling technique,double immunofluorescent staining,combined with proteasomal inhibition were used to investigate the NCT expression in NCT stable cell line.RESULTS: Treatment of the cells with proteasomal inhibitors significantly increased both endogenous NCT(produced by the cell itself) and exogenous NCT(produced by the gene transfection) in SH-SY5Y cells.The effect of specific proteasomal inhibitor lactacystin on NCT expression was in time-and dose-dependent manners.Pulse-chase metabolic labeling experiment showed that the turnover of newly-synthesized radio-labeled nicastrin protein was blocked by lactacystin.The results of double immunofluorescent staining showed that NCT and ubiquitin were co-located in the cells.CONCLUSION: The proteasome is involved in the degradation of NCT in neuronal cells,and NCT is ubiquitinated before degradation.