Study On The Regulation Of Brain Microenvironmental Changes And MicroRNA In The Pathogenesis Of Alzheimer’s Disease

Background:Alzheimer’s disease（AD）has become an important disease threatening the health of the elderly,with a very high morbidity and mortality and imposes a great burden on families and society.is recognized as a pathological factor that may lead to AD.β-amyloid peptide（Aβ）is recognized as a pathological factor that may lead to AD.Theβ-site amyloid precursor protein cleaving enzyme 1（BACE1）is the rate-limiting enzyme in the process of cleavage of amyloid precursor protein（APP）to Aβ.Studies have shown that BACE1 mRNA[instructive relationship]can be regulated by noncoding RNA（ncRNA）in brain tissue,affecting the synthesis of BACE1 protein,and thus affecting the occurrence and development of Alzheimer’s disease.The endoplasmic reticulum stress,oxidative stress,Inflammatory environment,hypoxia,glucose deficiency and other microenvironment changes in the brain may cause changes in neuronal function,thereby promoting the pathogenesis of Alzheimer’s disease.Objective:To investigate the relationship between microRNA（miRNA）andβ-site amyloid precursor protein cleaving enzyme 1（BACE1）protein,BACE1 mRNA expression under the simulating brain microenvironmental changes in Sprague Dawley（SD）rat primary neuronal cells.Method:Screening for target miRNAs associated with AD based on pre-clinical microarray and bioinformatics techniques.The primary neuronal cells of SD rats were simulated with endoplasmic reticulum stress（ERS）by using thapsigargin（Tg）,lipopolysaccharide（LPS）and hydrogen peroxide（H₂O₂）,respectively.Inflammatory environment,cultured under mild oxidative stress conditions.In addition,miRNA-107,miRNA-22-5p,miRNA-134-3p,miRNA-1185-2-3p,miRNA-1909-3p mimics and inhibitor were transfected under various microenvironment conditions.The expression of BACE1 protein was detected by western blot under different microenvironment conditions.The expression of BACE1 mRNA and target miRNAs under different microenvironment conditions were detected by RT-PCR,and the relationship between them was analyzed.Results:After treatment of SD rat primary neuronal cells in the endoplasmic reticulum stress（ERS）group treated with 0.125μmol/Lol/Lol/L Tg,and BACE1protein and BACE1 mRNA levels were significantly up-regulated（p<0.05）;BACE1protein and BACE1 mRNA levels were significantly up-regulated in the Inflammatory environment group treated with 0.01 mg/ml LPS（p<0.05）;and in the mild oxidative stress group treated with H₂O₂ 0.25 mmol/Lol/L,BACE1 No significant changes were observed in either protein or BACE1 mRNA（p>0.05）.After transfecting miRNA-107,miRNA-22-5p,miRNA-134-3p,miRNA-1185-2-3p,miRNA-1909-3p inhibitor with the above three microenvironment changes,except miRNA-134-3p,BACE1 protein expression increased;after transfection of miRNA mimics,it was found that miRNA-107,miRNA-22-5p,miRNA-1185-2-3p group,BACE1 protein level decreased（p<0.05）,while miRNA-134-3p,miRNA-1909-3p no significant difference between the two groups（p>0.05）.Conclusion:Our results suggest that although microenvironmental changes can promote the pathogenesis of AD disease by altering BACE1 expression,changes in single microenvironmental conditions may not cause changes in BACE1 expression.The results of this study of microRNAs with down-regulated expression in AD patients contribute to our understanding of the pathogenesis of AD and may be the basis for new therapeutic strategies for the treatment of AD.However,further research is needed to determine which factors regulate the expression of BACE1 protein.