Elevated BACE1 mRNA Level is Associated with Lower miR-15a-5p and miR-19b-3p Expressions in Peripheral Blood Mononuclear Cells of Patients with Late-Onset Alzheimer's Disease: Wet Lab Results and Bioinformatics Analysis.

BACE1 promotes aggregation of β-amyloid in Alzheimer's patients' brains. MicroRNAs play roles in gene expression regulation. Furthermore, BACE1 is a target for microRNAs. There is a crosstalk between the peripheral and central immune systems in the etiology of Alzheimer's disease. This study investigates the alterations in expression of BACE1, along with miR-15a-5p and miR-19b-3p genes, in peripheral blood mononuclear cells (PBMCs) of late-onset Alzheimer's disease (LOAD) patients. The levels of BACE1 mRNA, miR-15a-5p, and miR-19b-3p were measured in PBMCs using a real-time quantitative PCR method. Cytoscape software was used to identify the putative target genes of these microRNAs. Significant increase in BACE1 levels (mean ± SD: 2.076 ± 0.5308), and decrease in both miR-15a-5p and miR-19b-3p expressions (0.3656 ± 0.1056 and 0.7296 ± 0.1933, respectively) were observed. Altered BACE1, miR-15a-5p, and miR-19b-3p expressions suggest novel indicators for early LOAD diagnosis. We illustrated target genes by which these microRNAs may regulate BACE1 expression.