Bioinformatics Analysis To Explore The Correlation Of SNAP25 And RPH3A On The Alzheimer’s Disease Risk

Objective: Alzheimer’s disease(AD)is a neurodegenerative disease characterized by cognitive and behavioral disorders.With the increasing of population aging,the incidence of AD is increasing year by year,which brings heavy burden to society and families.The main pathological features of AD were the senile plaques formed by amyloid β-protein(Aβ)deposition and nerve fiber tangles formed by Tau protein hyperphosphorylation.However,the pathogenesis of AD remains unclear.A large number of studies have shown that the pathogenesis of AD is closely related to synaptic function,vesicle transport and neurotransmitter release.Previous studies have shown that synaptic loss and abnormal function are considered to be pathological changes in the early stage of AD,and these changes are associated with cognitive dysfunction.Synaptic associated proteins play an important role in synaptic function and neuronal signal transduction.Therefore,this study mined AD synaptic associated proteins through bioinformatics analysis to explore potential pathways and targeted genes for AD diagnosis and treatment.Further prediction of AD risk genes by bioinformatics and molecular biology experiments provides scientific theoretical basis for exploring therapeutic targets of AD.·Methods: RNA sequencing microarray data sets GSE5281,GSE122063 and GSE39420 were downloaded from the Comprehensive gene expression database(GEO),and co-expression differential genes(DEGs)were identified.Functional enrichment analysis was performed by gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG).The protein-protein interaction Network(PPI)was constructed and analyzed using STRING,Cytoscape software and R language software to establish important AD-relateds key genes in the modules.The expression levels of synaptosomal associated protein 25(SNAP25)and Synaptic vesicle-associated proteins(Rabphilin-3A,RPH3A)in the brain of wild-type mice and AD model-APP/PS1 transgenic mice were analyzed by Western blot at different ages.The distribution and expression of SNAP25 and RPH3 A in the cerebral cortex of 9-month-old APP/PS1 transgenic mice and Wild Type mice(WT)were analyzed by immunofluorescence to verify the results of bioinformatics analysis.Results: A total of 127 differential genes(DEGs)composed of 10 up-regulated genes and 117 down-regulated genes were screened in GSE5281,GSE122063 and GSE39420 data sets.By KEGG,GO and DO enrichment analysis,DEGs enrichment is associated with syntaxin-1 binding,syntaxin binding,SNARE complex binding and calcium-dependent phospholipid binding,and is closely related to synaptic biological processes,SNARE complex binding and neurotransmitter release.SNAP25 was identified as the first significant gene in DEGs by analyzing GOplot string plot,double circle plot drawn by CytoNCA and Hub gene analysis.The PPI protein network construction,the relationship between the key modules and the Go-enriched gene and the function of the network map show that SNAP25 and RPH3 A are correlated in the binding process of synaptopsnare complex.The results of Western blot showed that the expression levels of SNAP25 and RPH3 A in the cerebral cortex of APP/PS1 transgenic mice were significantly lower than wild-type mice at 6 and 9 months of age.Immunofluorescence results showed that the cortical neurons of APP/PS1 mice decreased at 9 months,and the expression levels of SNAP25 and RPH3 A in synapses were significantly lower than those of wild-type mice.Conclusion: Synaptic associated proteins SNAP25 and RPH3 A may participate in the pathological mechanism of AD through SNARE complex in regulating synapses and intrapsynaptic vesicles,providing scientific basis for SNAP25 and RPH3 A to become risk genes for AD pathogenesis,and providing new therapeutic directions and targets for the diagnosis and treatment of AD.