Analysis Of β-amyloid Induced Intracellular Effect

Alzheimer’s disease (AD) as we know is a senile dementia, it is the mostage-related neurodegenerative condition. According to the research, prevalence ratesof AD range from~10%of individuals>65and up to50%of individuals greater than85years of age. With the study of AD pathogenesis mechanism, people foundbeta-amyloid played an important role in the occurrence and development of AD. Butit is still not really clear about the beta-amyloid induce intracellular effect, especiallythe role of protease in the AD pathogenesis mechanism.ILKAP (integrin-linked kinase-associated phosphatase) is an important proteinphosphatase which was discovered in recent years. According to the reports, ILKAPplay a really important role in the Integrin and JNK/MAPK signaling pathway. And aswe know, GSK3β which is important in the Integrin signaling pathway and JNK areimplicated in AD pathogenesis mechanism.Our group found palladin played a specific role in mediating the ILKAP tomodulate ILK-Integrinβ signaling pathway. In order to investigate how beta-amyloidinduce intracellular effects in which ILKAP and palladin are involved, we analyze thechanges of ILKAP and palladin when the beta-amyloid exist in the extracellularmatrix of SH–SY5Y.First of all, we prepare4different Abeta42species (monomers, oligomers,profibrils and fibrils). Though different Abeta42aggregates have different toxicity, themost Abeta42toxic aggregates are its oligomers and profibrils. We detected the cellsurvival rate and cell morphological changes after incubated for12h,36h and60h at4different Abeta42concentrations as extracellular matrix. We found that with theincrease of Abeta42concentration and the extension of the incubation time, the cellsurvival rate decreased and the number of changing cell morphology increased. Inorder to study the changes of ILKAP and palladin, we detect the changes of theirlocation and expression level by the immunofluorescence and western blot to. We found that with the increase of Abeta42concentration and the extension of theincubation time, ILKAP and palladin were translocated near to the plasma membrane.With the increase of Abeta42concentration, the expression level of ILKAP andpalladin increased at first stage and then decreased. It is suggested that the ILKAP orpalladin played a certain role during the neurotoxic injury caused by Abeta42inSH-SY5Y.It has been reported that there are some relationship between ILKAP and otherproteins that are involved in AD pathogenesis. So, the results of this thesis willprovide some evidence for beta-amyloid induce intracellular effect, and provided atheoretical basis for exploring AD pathogenesis mechanism.