Molecular Mechanism Of Chloroquine On APP Metabolism In Alzheimer's Disease

Objective To investigate the genotype distribution of apolipoprotein E(Apo E)in patients with Alzheimer's disease(AD)and healthy elderly in Chongqing and to discuss the relation between AD and Apo E,thus predicting the likelihood of AD occurrence in crowd and offering basis for the prevention of AD.Materials and Methods Participants included 4251 normal subjects,404 AD patients and 390 age corresponding healthy elderly residing in Chongqing city were genotyped.The whole blood of patients with Alzheimer's disease(AD);The whole blood of healthy elderly;Extracted genomic DNA from human blood;Polymerase chain reaction-restriction fragment length polymorphism;Agarose gel electrophoresis;Hin P1 I restriction enzyme for digestion;Polyacrylamide gel electrophoresis and Silver staining.Results The results showed that the ?3 allele presented the highest frequency(82%),followed by ?4(6.25%)and ?2(11.75%)in general population.?3/?3 genotype carriers were the most common ones(64.19%)and the ?4/?4 had the lowest frequency(0.59%).The frequency of Apo E?4 allele frequency in AD(15.35%)was significantly higher than control(10.00%).Conclusion Those carriers of two ?4 allele have five time higher risk to develop AD.Our study demonstrates that Apo E?4 allele is a risk factor of AD for Chinese population.Objective Neurodegenerative disease is a kind of progressive damage to the central nervous system neurons and death cause movement dysfunction and a class of diseases characterized by impaired cognitive function.Neurodegenerative disease is the fourth cause of death.Alzheimer's disease(AD),as one of the common neurodegenerative disease,seriously affects the health of human beings throughout the world and the economy.Although a mass of the basic researches and clinical trials about the AD were performed,its pathogenesis is still unknown.In recent years,studies have reported that chloroquine as autophagy regulator for the treatment of neurodegenerative diseases is valuable to explore.But the role of chloroquine in the treatment of neurodegenerative disease has not been verified by a lot of researches.In this study we examined how chloroquine affected APP metabolism for Alzheimer's disease in vivo and in vitro.Materials and methods Different cell lines(SH-SY5 Y,2EB2,20E2)were used to detect the amyloid amyloid protein(APP)processing with different concentration of chloroquine respectively.The APP23/PS45 double transgenic mice were intervened with chloroquine.6 week-old of positive transgenic mice were randomly divided into control group and experimental group(drug intervention group).Mice in chloroquine group were intraperitoneally injected with 50 mg/kg chloroquine,and in the control group,mice were given the same volume of PBS buffer for four weeks consecutively.Morris water maze test was used to explore the spatial learning and memory ability.The levels of APP,CTF,BACE1,ADAM10 and PS1 protein were determined by Western blotting,the concentration of A?40 and A?42 was measured by ELISA and immunohistochemical staining was used to detect the number of senile plaques.Results In vitro study,with the increasing drug concentration of chloroquine,APP had no significant difference,and APP processing product CTF was given priority to C89 increasing,the level of BACE1 was also increased in 2EB2 cells.In 20E2 cells,APP and cutting products CTF were both increased.In SH-SY5 Y cells,the APP and cutting products CTF,ADAM10,BACE1 protein levels were increased,but no significant difference was found about the PS1 protein.In vivo experiment,compared with control group,the escape latency,total swimming distance and the times of crossing the platform had no significant difference in the experimental group.The levels of protein APP,?-CTF,?-CTF and BACE1 were increased.However,the level of PS1 had no significant differnce.A?40 / A?42 were reduced.The number of senile plaques was also decreased.Conclusion We found that chloroquine can affect the APP processing either in vitro or in vivo.Chloroquine treatment reduces the deposition of A? to form neuritic plaques in the brain of AD model mice APP23/PS45,but we did not find chloroquine can improve learing and memory impairments in the AD model mice.Our study suggests that chloroquine may used as a drug for AD treatment.However,further extensive studies should be conducted for improving cognitive deficits.