| Alzheimer’s disease(AD)is a chronic neurodegenerative disease with progressive memory loss,cognitive dysfunction and personality changes as the major symptoms,which is the most common form of dementia.The pathological features include senile plaques by the accumulation of beta amyloid(Aβ),neurofibrillary tangles(NFTs)by the abnormal aggregation of tau protein,and loss of neurous in cerebral cortex and hippocampus.Among them,the deposition of Aβ plays an important role in the pathogenesis and pathological progression of AD.China is the only country with an aging population of more than 100 million currently.Therefore,the number of patients with AD is increasing rapidly and it is the most important health problem in the aging society.So it is urgent to improve the recognition rate and early diagnosis rate of dementia.The current diagnostic criteria for AD are based on clinical manifestations,combining with history,mental status,cognitive and psychological test results,and excluding other diseases that may lead to dementia.The diagnostic criteria of AD published by NIA-AA in 2011 included biomarkers,that is the functional imaging showing a decrease in glucose metabolism or a decrease in Aβ42 and/or an increase in tau protein in the cortex of a particular area of the brain.However,due to limited resource and operational difficulties,these biomarkers can’t be widely used in early screening of AD.Therefore,the clinical diagnosis of AD is far behind the occurrence and development of AD.It is impossible to achieve early diagnosis and prevention.Exosome is a circular or elliptical monolayer with a diameter of about 40~150nm,which can be released by many types of cells.Exosomes can exist stably in body fluids.at the same time,it can effectively avoid the mononuclear macrophage phagocytosis and freely pass through the vessel wall and extracellular matrix because of its small volume.Exosomes can be widely distributed in plasma,milk,urine and other body fluids,which can finally realize the cycle of fusion with surrounding cell membrane.Exosomes can carry types of bioactive molecules,including a wide variety of proteins,lipids,and nucleic acid components.They can regulate the information of the receptor cells by multiple pathways and multisites and then more satisfy the need of body.Exosome’s communication skills are not all beneficial result,sometimes the transportation of pathogenicity protein or denatured protein by exosomes vector will aggravate the development of nervous system diseases.For example,it have shown that exosomes can transport alpha synuclein related to Parkinson’s disease through intercellular transport in vitro experiments.Some researchs have shown that exosomes can release amyloid beta associated with alzheimer’s disease,adding to the sedimentary process of these proteins in the brain.Exosomes contain a variety of proteins and genetic material which could be considered biomarkers of disease.The research of exosomes gradually is used for clinical diagnosis and treatment.Some researchers think that miRNA can be used as diagnostic markers of lung cancer,the proteins map of urine samples may also help the diagnosis of renal disease.The exosomes can be used to treat the patients with Alzheimer’s disease by reducing the amyloid beta protein.Objective:First we will extract and identify the exosomes in the serum of patients with Alzheimer’s disease and normal elderly people.Then we will screen and identify exosomes proteins related with Alzheimer’s disease by use proteomics technology,which can provide a theoretical basis for exploring early diagnostic marker of Alzheimer’s disease and find the biological target for preventing and treating AD.Methods:The Exo Quick kit was used to extract exosomes from the serum of patients with Alzheimer’s disease and normal elderly people.The morphological characteristics were observed by transmission electron microscope,and western blot was used to identify the marker CD63 in the surface of exosomes,BCA method was used for quantitative analysis of the exosomes proteins.The isolated differential proteins from exosomes were identified by two-dimensional gel electrophoresis and mass spectrometry.Results:1.Transmission electron microscopy showed that the exosomes in serum were round or oval,with an average diameter of 30-150 nm and a complete lipid envelope.2.The results of western blot showed that the specific marker CD63 was positive in serum derived exosomes.3.Two dimensional gel electrophoresis showed that there were about 26 differential proteins expressed over 3 times,of which 10 were up regulated in AD patients and 16 down regulated,and 3 protein points were selected for mass spectrometric analysis and identified as vitamin D binding protein(Vitamin D-binding protein,VTDB),CD5 antigen(CD5 antigen-like,CD5L),immunoglobulin heavy chain(Immunoglobulin heavy constant mu,IGHM).Conclusions:1.Exosome was successfully isolated from the peripheral serum from patients with Alzheimer’s disease by using the kit method,which provides a good technical basis for further study of the relationship between exosome protein and Alzheimer’s disease.2.Screening and identification of 3 differential proteins: vitamin D binding protein(Vitamin D-binding protein,VTDB),CD5 antigen(CD5 antigen-like,CD5L),and Methods: immunoglobulin heavy chain(Immunoglobulin heavy constant mu,IGHM)may be associated with the pathogenesis of Alzheimer’s disease,and can provide candidate proteins for exploring biomarkers of Alzheimer’s disease. |
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