The miR-146a-5p and miR-125b-5p levels as biomarkers for early prediction of Alzheimer's disease

Abstract

BackgroundAlzheimer's disease (AD) is an age-related neurodegenerative disease. Prediction and diagnosis of AD, particularly at the early stages, remain challenging due to the lack of biological biomarkers for diagnosis. microRNAs play an essential role in controlling the gene expression level at the post-transcriptional level of mature mRNA and repression of many target genes. In addition, evidence detects that miRNA has a significant role in the biogenesis of AD, which enhances their utility as promising biomarkers for early disease diagnosis, mainly if directly analyzed from circulation. Therefore, we aimed to possibly use miR-125b-5p and miR-146a-5p levels in circulation as novel biomarkers to detect AD. Materials and methodsLevels of miRNAs from the plasma of 30 Alzheimer's participants were compared with miRNA levels of 30 non-dementia cohorts matched by gender and age. Total RNA was purified, cDNA was synthesized, followed by screening for miR-125b-5p and miR-146a-5p expression by real-time quantitative reverse transcriptase PCR (RT-qPCR) to estimate variations in miR-125b-5p and miR-146a-5p expression levels using relative quantification. ResultsmiR-146a-5p levels were significantly down-regulated in AD patients compared to healthy subjects (P = 0.0013). Similarly, miR-125b-5p levels were detected at a low expression in the dementia cohort (P ≤0.0001). In addition, the mini-mental state examination MMSE score shows a significant difference (P ≤0.0001). Receiver operating characteristic (ROC) analysis confirmed that both miRNAs could use as a diagnostic biomarker for AD. ConclusionOur findings revealed that alterations of circulating plasma levels of miR-125b-5p and miR-146a-5p might serve as early noninvasive diagnostic markers for predicting AD patients.