Decoding microRNA-Protein Interaction Networks in Alzheimer's Disease: Molecular Mechanisms and Clinical Implications.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by memory loss, cognitive decline, and neuronal dysfunction. Despite thorough research efforts, effective disease-modifying treatments have yet to be discovered. MicroRNAs (miRNAs), small noncoding RNAs that control gene expression after transcription, have become key factors in AD development. Changes in miRNA levels influence critical molecular pathways such as amyloid precursor protein (APP) processing, tau phosphorylation, oxidative stress, neuroinflammation, and synaptic plasticity, all of which contribute to neuronal damage. By increasing β-secretase (BACE1) activity, downregulation of miR-29a/b and miR-107 encourages the buildup of amyloid-β (Aβ) and the development of plaques. Through the deregulation of the CDK5 and MAPK pathways, overexpression of miR-125b and decreased levels of miR-132/212 lead to tau hyperphosphorylation. While oxidative stress-associated miRNAs like miR-34a and miR- 21 worsen mitochondrial malfunction and neuronal death, pro-inflammatory miRNAs like miR-146a and miR-155 cause NF-κB-mediated signalling and glial activation. Circulating miRNAs found in blood and cerebral fluid are potential, minimally invasive indicators for tracking the course of a disease and making early diagnoses. Additionally, therapeutic manipulation with antagomiRs or miRNA mimics has the potential to prevent neurodegeneration and restore normal gene regulation. This review deciphers the molecular mechanisms underlying miRNA dysregulation in AD and explores their translational potential as biomarkers and therapeutic targets. A comprehensive understanding of miRNA-protein interaction networks could facilitate the development of targeted, precision- based interventions for Alzheimer's disease.