Analysis Of MiRNAs Associated With Alzheimer’s Disease And Their Clinical Value

Part I Analysis of miRNAs related with Alzheimer’s and prediction of hub genes based on bioinformaticsObjective:To explore miRNAs related to Alzheimer’s disease(AD)and their hub genes on the basis of bioinformatics,in order to discover their potential mechanisms in AD.Methods:Dataset GSE46579 of AD related miRNAs expression was obtained from the Gene Expression Omnibus(GEO).The differentially expressed miRNAs was screened by "limma" package of R language software.miRDB,miRWalk and Target Scan databases were used to predict the Target genes of differentially expressed miRNAs,and the intersection was taken respectively.DAVID database was used to analyze the GO function and KEGG signal pathway enrichment of target genes of differentially expressed miRNAs.The String database was used to construct the Protein Protein Interaction(PPI)network of target genes of different miRNAs.Cytohubba,the tool of Cytoscape,was used to screen the hub gene.Results:Seven miRNAs related to Alzheimer’s disease were selected from the dataset GSE46579,including miR-1285-5p,miR-144-5p,miR-148a-3p,miR-101-3p,miR-173p,miR-660-5p,miR-144-3p.The potential intersection target genes of miRNAs were predicted by three online databases as follows:49,1,25,19,176,17,7.GO enrichment analysis showed that the target genes of differentially expressed miRNAs were mainly involved in 22 biological processes(BP),16 cell composition(CC)and 22 molecular functions(MF).KEGG analysis showed that the target genes of differentially expressed miRNAs were mainly concentrated in 16 signaling pathways,including mTOR signaling pathway,AMPK signaling pathway,Glioma,Hippo signaling pathway and so on.PPI network show core protein are PRPF19,SNRPD3,CDC5L,IGF1R,EIF4A3,CDH1,SNW1,RAB11A,SMAD4,IGF1.Conclusions:miR-1285-5p,miR-144-5p,miR-148a-3p,miR-101-3p,miR-17-3p,miR660-5p,miR-144-3p;PRPF19,SNRPD3,CDC5L,IGF1R,EIF4A3,CDH1,SNW1,RAB11A,SMAD4,IGF1 may participate in the development process of Alzheimer’s disease through multiple signaling pathways.They may be important for the prevention,diagnosis and treatment of Alzheimer’s disease.Part Ⅱ The relative expression of miR-144-5p in serum of patients with AD and its clinical significanceObjective:To verify the expression levels of miR-144-5p in peripheral blood of patients with AD and normal controls by serological test,and discuss the possibility of miR-144-5p as a clinical biomarker for AD.Methods:Fifty patients with Alzheimer’s disease patients(AD group)and forty Normal controls(NC group)who met the criteria in our hospital were enrolled in this study.The expression levels of serum miR-144-5p was detected by real time fluorescence quantitative PCR(qRT-PCR).Next,the relationship between the expression levels of miR-144-5p in serum of patients with AD and the Mini Mental State Examination(MMSE)scores were analyzed.Clinical Dementia Rating(CDR)score was used as the standard,patients in the AD group were divided into mild,moderate and severe groups;and differences between the expression levels of serum miR-144-5p of patients with AD and different severity of AD were analyzed.ROC curve was used to evaluate the value of the expression levels of serum miR-144-5p in the diagnosis of AD.Results:1.The expression level of miR-144-5p in serum of the AD group was 5.17312.675,and that of the NC group was 8.750± 1.735.The expression level of miR-144-5p in serum of the AD group was significantly lower than that of the NC group,and the difference between the two groups was statistically significant(P<0.001).2.There is a positive correlation between the expression level of miR-144-5p in AD patients’serum and their MMSE score(r=0.846,P<0.001).3.The expression level of miR-144-5p in mild,moderate and severe AD groups showed an overall downward trend,and there were significant statistical differences in the expression level of miR-144-5p between severe and mild AD groups,as well as between moderate and severe AD groups(P<0.001).Although the expression level of miR-144-5p in moderate and severe AD groups showed a downward trend.But there was no statistical difference(P>0.05).4.The area under the ROC curve of miR-144-5p in serum for AD diagnosis was 0.869(95%CI:0.797～0.940,P<0.001).Conclusions:In this study,the expression level of miR-144-5p in serum of patients with AD was lower than that of normal people,and it was positively correlated with the degree of cognitive disorder,suggesting that miR-144-5p had a potential as a serological biomarker of AD.