ITRAQ-based Proteomic Analysis Of APPSw,Ind Micc Provides Insights Into The Early Changes In Alzheimer's Disease

Background Alzheimer's disease is a kind of neurodegenerative disease, mostly attack people over 70 years old. Morbidity increase as aging. In the condition of society gradually into the process of aging, AD become the fourth largest cause in people over 65 years old and a increasingly grave problem of public hygiene. Patients would suffer psychiatric syndromes such as depression, acedia, agitation, aggression, psychosis, and more proverbial behavior symptoms of AD, such as memory impairment, cognitive dysfunction in addition. Patients gradually lose ability of daily living, slip onto unconsciousness and die of complication like infection. Etiologies of AD conclude familial inheritance, head trauma, other somatopathy, social psychological factors. However, people are not conscious about pathogenesis, and lack of early diagnose criteria and intervention means. It's useless in reversing or slowing down the disease by medicine intervention therapy after confirmed diagnosis in the late stage of AD. So, finding early diagnostic biomarker is an urgent arrangement in the study of Alzheimer's disease. Purpose Exploring early alteration of molecular biology in AD model mice from the list of iTRAQ and screening out significantly changed proteins in two kinds of AD model mice brain result and can influence expression of (3-amyloid precursor protein in murine neuroblastoma N2a cell as potential biomarkersand therapeutic targets.Methods Applying isobaric tags for relative and absolute quantitation(iTRAQ) test proteins expression in hippocampus of J20 and wild-type mice and get remarkable changed proteins. Using real-time fluorescence quantitative PCR to examine level of related mRNA in hippocampus of J20 and APP/PSEN1 mice. Detecting the difference of proteins in separated brain regions of APP/PSEN1 mice from wild-type mice by western blot. Constructed shRNA-plasmids and transfected them into N2a/APP cell, verified effect of knock-down by RT-PCR and western blot. By the means of western blot and immunocytochemistry we analyzed the variation of APP expression in N2a/APP after knocking-down of relevant proteins. Results We find over 700 proteins changed in hippo of J20, and over 400 among them have significant variation. We classified them into 32 categories according to their biological function. Proteins associated with metabolic process and extracellular region mainly increase, while all synapsins have a decline. J20 and APP/PSEN1 have distinction in the expression of mRNA and protein. Rac1 notably increase in cerebellum, ?-spectrin remarkably decrease in hippo and cortex of APP/PSENl mice. Knocking-down of ?-spectrin has obvious effect on APP expression in N2a/APP cell line. Conclusion Above results we got a number of potential early biomarker of AD, and we found?-spectrin and may play a role in early APP cellular trafficking.