miR-132 and Its Exosomal Form in Alzheimer's Disease: Linking Epigenetic Regulation to Neurodegeneration.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by distinct neuropathological features, including amyloid-beta (Aβ) plaques, neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau, synaptic dysfunction, and chronic neuroinflammation. MicroRNAs (miRNAs), as critical post-transcriptional regulators, exert a profound influence on central nervous system (CNS) function and are increasingly implicated in the pathogenesis of AD. Among these, miR-132 stands out as a brain-enriched miRNA that is consistently downregulated in AD, affecting various aspects of the disease, from Aβ and tau pathologies to synaptic integrity and neuronal survival. Simultaneously, exosomes, nanoscale extracellular vesicles, play a crucial role in intercellular communication and are capable of transporting miRNAs across biological barriers such as the blood-brain barrier. This comprehensive review synthesizes the current understanding of miR-132's intrinsic roles in neuronal health and its dysregulation in AD, elucidates the mechanisms underlying exosome-mediated communication, and explores the complex interplay between exosomal miR-132 and AD pathology. Furthermore, we examine the significant role of epigenetic regulation in modulating miR-132 expression and its broader implications for neurodegeneration. By evaluating the diagnostic potential of miR-132 and its exosomal form as non-invasive biomarkers, as well as their promising therapeutic applications, this review underscores the multifaceted importance of miR-132 in AD. Challenges in current research, particularly with regard to the standardization of exosome isolation methods and the complexity of miRNA regulatory networks, are discussed, highlighting the need for future comprehensive studies to translate these findings into effective clinical strategies for AD management.