The Effect Of Preventing Aβ Deposition By Peptide Vaccine Expressing Aβ3-10 On Tau Protein Phosphorylation And Neurofibrillary Tangles

objective:Alzheimer’s disease(AD)is the highest incidence of dementia worldwide and is an emerging global epidemic disease.Dementia is a major problem facing the aging society.Alzheimer’s disease(AD)is the most common cause of dementia in elderly patients and is characterized by a progressive decline in cognitive function,which typically begins with deterioration of memory.The worldwide prevalence of dementia is estimated to be as high as 44 million and is predicted to reach 66 million by 2030 and115 million by 2050,with approximately two-thirds of those patients living in developing countries.AD is characterized by the accumulation of extracellular β-amyloid(Aβ)plaques,the progressive appearance of intracellular tau pathology,Increase of soluble Aβ and hyperphosphorylated tau 、 Aβ deposition in insoluble amyloid plaques together with neurofibrillary tangle(NFTs)also represent the hallmark of the most common,late onset form of Alzheimer’s disease(LOAD).Intracellular accumulation of NFTs,which are composed of hyperphosphorylated form of the microtubule-associated protein tau,represents a later event during disease progression and strongly correlates with neuronal death and cognitive impairments.At present,various pathological processes are known to be involved in AD.However,the amyloid cascade hypothesis and the amyloid beta(Aβ)toxicity hypothesis have dominated research for decades.And the deposition of Aβ peptide in the brain is considered a central event in AD.This updated theory currently suggests that accumulation of Aβ peptides particularly in a highly toxic oligomeric form is the primary pathogenic driver,that downstream leads to tau hyperphosphorylation,NFT formation and ultimately to synaptic and neuronal loss.Tau is a microtubule-binding protein but dissociates from the microtubules and accumulates in neurons as it becomes highly phosphorylated at multiple sites,resulting in the impairment of microtubule assembly and function,The molecular mechanism underlying amyloid beta’s role in the hyperphosphorylation of tau proteins was not known.Although AD was first discovered over a hundred years ago,and substantial progress has been made in understanding the etiology of the disease,there are still no effective therapeutic or definitive diagnostic approaches available.Numerous therapeutic interventions are under investigation to prevent and treat AD.Among the more exciting and advanced of these approaches is vaccination.Active and passive Immunotherapy targeting only Aβ has been successful in many AD model animal trials,However,there is very limited evidence in human studies of clinical benefits from these approaches.This might have been related to the immunization having begun too late in the disease process.Questions that have come up from previous work which are critical for the development of successful immunotherapy include identification of the ideal target and the timing of therapy.Recent results suggest that the abnormal Tau protein plays a key role in the development of neurodegeneration and learning memory disorders in AD patients.The research on Tau protein mainly focuses on the modification of protein translation,namely abnormal hyperphosphorylation,so far,no approaches targeting both pathologies concurrently has been attempted,until very recently.The design of future more effective immunomodulatory approaches will need to target all aspects of AD pathology,as well as specifically oligomeric Aβ and tau.In order to better understand the pathologic mechanism of AD,we need to carefully analyze the interaction between Tau and Aβ to determine the prospective AD therapy research direction.the best design for a vaccine that is both specific and safe。Therefore,this experiment is aimed at finding the way to inhibit the excessive phosphorylation of tau protein and the timing of vaccination.In order to establish an effective removal of Aβ deposition and inhibition the excessive phosphorylation of tau protein,the present study build Aβ3-10-KLH peptide vaccine avoiding meningoencephalitis,vasogenic edema and micro-cerebral hemorrhages that can occur with the use of vaccine.Present study examined the in vivo effects of Aβ3-10-KLH peptide vaccine in one-month of the APP/PS1/tau triple-transgenic(3x Tg-AD)corresponding to early stages of the disease,showed no behavioral and psychological symptoms of dementia-like behaviors were immunotherapied.In this report we studied effect of immunotherapy of Aβ3-10-KLH peptide vaccine on the cognitive function,and tau pathology in 3x Tg-AD mice.。we found Aβ3-10-KLH vaccine produced high levels of anti-Aβ antibody,and reduces the tau protein phosphorylation of transgenic mouse tissue and nerve fiber tangle.The cognitive function of 3x Tg-AD was improved by the Aβ3-10-KLH vaccine.High levels of anti-Aβ antibody was significantly correlated with reduced tau hyperphosphorylation and improvement in cognition.This study provides a novel vaccine for the treatment of AD,and provides appropriate timing for the active immunization of the vaccine,providing further evidence of the amyloid cascade reaction theory.Our findings demonstrate the potential of using Aβ3-10-KLH peptide vaccine as a therapeutic approach to prevent and treat Alzheimer’s disease.Method:The Keyhole limpet hemocyanin(KLH)was conjugated to the Aβ3-10 peptide and synthesized by Gen Script Co.Ltd.china.The Aβ3-10-KLH polypeptide vaccine was administered by subcutaneous injection to immunize 3x Tg-AD mice.PBS was injected into mice in the same way,as a negative control group,and with a wild type mice control group.This study used ELISA to detect Aβ antibody concentration,used Morris water maze to test 3x Tg-AD mice cognitive function,tau protein phosphorylation and nerve fiber tangles was detected by immunohistochemical staining 、 Western blot 、 Brain homogenate.At the same time the results were compared with those of the PBS-treated group and the wild type mice control group.Results : 1.The anti-Aβ antibody was detected by ELISA and the concentration of anti-Aβ antibody induced by Aβ3-10-KLH vaccine was at a high level.2.After 7immunizations with Aβ3-10-KLH vaccine,the 3x Tg-AD mice were tested by Morris water maze.The PBS-treated mice and wild type mice were used as control groups.The cognitive function of these mice was significantly improved by Aβ3-10-KLH vaccine.3.After7 immunizations with Aβ3-10-KLH vaccine,the brain tissue 3x Tg-AD mice were detected by imnunohistochemical staining 、 Western blot and Brain homogenate.and wild type mice were used as control groups.Total Tau、P-Tau and insoluble tau protein of these Aβ3-10-KLH-treated mice was significantly reduced compared with the PBS-treated mice.Conclusion:1.The anti-Aβ antibody was detected by ELISA and the concentration of antibody induced by Aβ3-10-KLH vaccine was at a high level.2.The early immunization of.Aβ3-10-KLH vaccine could improve the cognitive function of3 x Tg-AD mice.3.Total Tau protein、P-Tau and insoluble tau protein of these mice was significantly reduced by The early immunization of Aβ3-10-KLH vaccine.