| Objective: The purpose of this study was to detect the expression level of mi RNAs in the serum of patients with mild cognitive impairment(MCI)in aluminum mining areas,explore mi RNAs that may reflect the differential expression of aluminum-induced cognitive impairment,and provide a new biomarker for the clinical diagnosis of aluminum-induced cognitive impairment.To provide reference for further study of the pathogenesis of cognitive dysfunction.Methods:(1)The Simple Mental State Scale(Mo CA)was used to investigate the cognitive ability of older people over 60 years old in aluminum and non-aluminum mining areas;(2)inductively coupled plasma-mass spectrometry,The contents of aluminum(Al),copper(Cu),manganese(Mn)and zinc(Zn)in serum of aged people over 60 years old in aluminum mining and non-aluminum mining areas were measured and compared by ICP-MS.(3)The cognitive ability of older people over 60 years old in aluminum and non-aluminum mining areas was analyzed;(4)The relationship between serum Al,Cu,Zn,Mn and Mo CA score was analyzed.(5)The second generation of high-throughput sequencing technology was used to detect the differentially expressed mi RNAs in serum between the high-aluminum cognitive impairment group and the high-aluminum cognitive normal group;(6)mi RDB,mi RWalk and mi RTar Base databases were used to predict the target genes of different mi RNAs,and the intersection of the three databases was taken as the target genes.(7)GO functional annotation and KEGG pathway enrichment analysis of target genes were performed using DAVID 6.8 database;(8)According to literature review and experimental results,differentially expressed mi RNAs were selected,and the serum expression levels of the elderly in the high-aluminum cognitive impairment group and the high-aluminum cognitive normal group,and the high-aluminum cognitive normal group and the low-aluminum healthy control group were detected by real-time quantitative PCR.(9)Real-time quantitative PCR was used to detect the expression relationship of serum β-secretase 1(BACE1)gene between the high aluminum cognitive impairment group and the high aluminum cognitive normal group.(10)The concentration of serum β-secretase 1(BACE1)protein in the high aluminum cognitive impairment group and the high aluminum cognitive normal group was determined by enzyme-linked immunosorbent assay ELISA.Results:(1)In Mo CA evaluation,the score of aluminum mining area was(20.74±8.07),and that of non-aluminum mining area was(23.8±7.42).Compared with non-aluminum mining area,Mo CA score of aluminum mining area was significantly decreased(t=2.252,P<0.05).(2)Compared with non-aluminum mining area,the level of serum trace metal elements in the elderly aged over 60 years old was higher(P<0.05);There was no statistical significance in serum trace elements of copper,zinc and manganese(P>0.05).(3)There was a negative correlation between aluminum and Mo CA score(P<0.05,B=-0.699),indicating that the more aluminum content,the smaller the Mo CA value,copper,zinc,manganese(P<0.05),the difference was not statistically significant.(4)The second generation of high-throughput sequencing technology was used to detect serum differential mi RNAs between the highaluminum cognitive impairment group and the high-aluminum cognitive normal group.The top8 mi RNAs that were most significantly down-regulated were: hsa-mi R-708-3p,hsa-mi R-485-5p,hsa-mi R-127-5p,hsa-mi R-30c-2-3p,hsa-mi R-135a-5p,hsa-mi R-3059-5p,hsa-mi R-384,hsa-mi R-431-3p;(5)The GO analysis results of the top 8 mi RNAs with the most significant down-regulation showed that the target genes were mainly concentrated in biological processes such as regulation of RNA polymerase II promoter transcription(GO:0006357)and signaling(GO:0007165).The cellular processes are concentrated in synapses between neurons(GO:0098984)and postsynapses(GO:0099572).It was enriched in PDZ domain(GO:0030165),protein binding(GO:0003725)and other molecular functional synapses.(6)PI3K-Akt-m TOR signaling pathway and GMP-Pkg signaling pathway(hsa04022)were predicted for the most significantly down-regulated first 7mi RNAs.(7)Real-time quantitative PCR detection results showed that compared with the high-aluminum cognitive normal group,the serum mi R-384 level of cognitive impairment patients in high-aluminum exposed areas was lower,and the difference was statistically significant(P<0.05),while there was no statistically significant difference between the high-aluminum cognitive normal group and the non-aluminum healthy control group(P>0.05).(8)The results of fluorescence quantitative PCR showed that compared with the high-aluminum cognitive normal group,the level of BACE1 gene in serum of cognitive impairment patients in high-aluminum exposed areas was increased,and the difference was statistically significant(P<0.05).(9)BACE1 protein expression increased with the increase of aluminum dose,and the difference between low-dose group and control group was statistically significant(P<0.05),while the difference between medium-dose and high-dose group and control group was statistically significant(P<0.05).Conclusions:(1)Compared with non-aluminum mining area,Mo CA score in aluminum mining area is significantly lower,suggesting that aluminum can cause cognitive decline;(2)Compared with the non-aluminum mining area,the serum level of aluminum in the aluminum mining area is higher,suggesting that the aluminum mining area poses a potential threat to the health of the surrounding residents;(3)The top eight mi RNAs most significantly downregulated in the high-aluminum cognitive impairment group were hsa-mi R-708-3p,hsa-mi R-485-5p,hsa-mi R-127-5p,hsa-mi R-30c-2-3p,hsa-mi R-135a-5p,hsa-mi R-3059-5p,HSA-Mir-3059-5p,hsa-mi R-384,hsa-mi R-431-3p;(4)The lower the level of mi R-384,the greater the possibility of cognitive impairment caused by aluminum;(5)The serum BACE1 level in the high aluminum cognitive impairment group was increased,suggesting that the higher the serum aluminum content,the higher the BACE1 level.(6)The expression of BACE1 protein increased with the increase of aluminum content. |
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