Study On The Molecular Mechanism Of Trehalose On APP Metabolism In Alzheimer's Disease And The Mechanism Of IL-17 On The Imbalance Of Immune Cell Expression In Human Metapneumovirus Infection

PART ? TREHALOSE FOR ALZHEIMER'S DISEASE IN MOLECULAR MECHANISM RESEARCH OF APP METABOLISMObjective: Alzheimer's disease(AD)is a commonneurodegenerative disease,caused by metabolic disorder of APP probably.Recent study showed that trehalose can be used for the treatment of neurodegenerative diseases with autophagy regulation and abnormal proteins clearance.However,the role of trehalose in AD therapy is still unclear.This study is to investigate the effect of trehalose on Alzheimer's disease-related APP molecules.Methods: Firstly,the amyloid precursor protein(APP),CTF,PS1 and A? were determined by western blotting and ELISA with different concentration of trehalose in 20E2 and HAW cell lines.Secondly,the APP was detected by western blotting with trehalose and/or chloroquine for 24 hours in 20E2 and HAW cell lines.Thirdly,HEK cell line was treated with different concentration of trehalose,and the cell viability of HEK cell line was measured by MTS.Lastly,the APP23 transgenic mice(AD model mice)were treated with trehalose.9 month-old of positive transgenic mice were divided into control group and trehalose treatment group randomly and treated with water and trehalose solution respectively,for 1month.APP and A? were determined by western blotting,ELISA and immunohistochemitry.The memory ability was valued by morriswater maze test.Results: In vitro study,the expression of APP,CTF and LC3II/LC3 I were significantly increased in the 50 m M trehalose group,while PS1 was not change in 20E2 and HAW cell lines.The expression of APP and CTF were increased in100 m M trehalose group compared with 50 m M trehalose group.The A?40 and A?42expression of 20E2 cell were decreased obviously in trehalose treatment group compared with control group.Compared with control group,the expression of APP was increased in trehalose group,trehalose and chloroquine group and chloroquine group.However,the expression of APP showed no statistical difference between chloroquine group and trehalose combine with chloroquine group.The expression of LC3II/LC3 I was obviously increased in trehalose group compared with control group.And the cell viability of HEK cell line showed no statistical difference with different concentration of trehalose treatment.In vivo experiment,the expression of APP and CTF were significantly increased,while PS1 and BACE1 were not change in brain tissue in trehalose treatment group.The expression of LC3II/LC3 I was increased while the expression of A?40 and senile plaque were sharply reduced.However,the morris water maze test showed no statistical difference.Conclusion: Our study showed the trehalose affect the APP processing both in vitro and in vivo.Trehalose treatment can reduce the expression of A? and senile plaque in APP23 transgenic mice(AD model mice).However,the learning and memory impairments cannot be improved by trehalse therapy apparently.PART ? SKEWED BALANCE OF IMMUNE CELL IN IL-17 DEFECT WITH HUMAN METAPNEUMOVIRUS INFECTIONObjective : Human metapneumovirus(h MPV)is a commoncause of respiratory infections in children.However,the mechanisms underlying the development of h MPV-induced pulmonary pathology remain unknown.Studies showed that IL-17 plays an important role in some inflammatory diseases of the airways,including asthma and chronic obstructive pulmonary disease.Our research is to characterize the role of interleukin(IL)-17 in human metapneumovirus(h MPV)-induced pulmonary inflammation.Methods: Wild-type(WT)and IL-17 knockout(KO)mice were infected with h MPV and the viral titer was measured by real-time quantitative PCR.Airway hyperresponsiveness was examined using whole-body plethysmography.Lung infection was characterized according to differential cell counts in the bronchiolar lavage fluid(BALF)and the histopathologic score.The percentages of regulatory T cell(Treg),Th1,and Th2 cells were evaluated by flow cytometry.Results: Although there was no significant difference in viral titer and histopathologic score between WT and IL-17 KO mice after h MPV infection,the total cell and neutrophil counts in BALF frominfected IL-17 KO mice were lower than those in BALF from infected WT mice.Also,the index of ventilatory function indicated that the Penh values in response to MCh exposure(25–50 mg/ml)were lower in IL-17 KO-infected mice than in WT-infected mice.Flow cytometry revealed that h MPV infection increased the percentage of Treg cells,but reduced the percentages of Th1 and Th2 cells,in IL-17 KO mice compared with WT mice.Conclusion: HMPV-infected IL-17 KO mice showed a skewed Treg profile.The percentage of Treg cells was increased upon infection,whereas the percentages of Th1 and Th2 cells were reduced,leading to a predominant anti-inflammatory response.