The Dynamic Regulatory Role of miR-132 in Adult Hippocampal Neurogenesis and Neural Stem Cell Development

Introduction: Neurogenesis and neural stem cell development in the adult hippocampus remains an understudied and controversial area of research. These processes are known to be regulated by the dynamic interplay of transcription factors, cell-niche signalling, and recently, microRNAs. microRNA-132 (miR-132) is one example of a miRNA that offers critical insight into neurogenesis and neural stem cell development. The aim of this study was to systematically review the current literature regarding the role of miR-132-mediated post-transcriptional regulation of adult hippocampal neurogenesis (AHN) and neural stem cell (NSC) development. Methods: The literature search consisted of research articles found in PubMed, MEDLINE, Google Scholar, Cochrane, and Scopus databases using combinations of the Medical Subject Headings (MeSH) keywords “micro-RNA 132”, “miR-132”, “adult hippocampal neurogenesis”, and “neural stem cell development” to filter initial results. The study abstracted data in regards to the modalities of miR-132-mediated post-transcriptional regulation and the histophysiological implications associated with AHN and NSC development. Results: miR-132 has been implicated in mediating AHN as well as NSC differentiation and integration into the adult hippocampal dentate gyrus. Knockdown and overexpression of micro-RNA 132 in studies have demonstrated that miR-132 acts as a regulator of several downstream pathways and biochemical targets, including p250-GAP, methyl CpG-binding protein 2, AMPA glutamate receptors, and the RAS/MAPK axon signaling pathway. The fine-tuned modulation of neuronal plasticity associated with miR-132 suggests a role in higher level cognition, learning, and neurodegeneration within the context of Alzheimer’s disease. Discussion: The findings that miR-132 serves as a regulator of AHN and NSC development have significant clinical implications, specifically towards better understanding the pathological basis of neurodegenerative disorders as well as the development of novel miRNA-based therapeutics.   Conclusion: The systematic review aggregated key findings on multiple potential biochemical targets and downstream feedback regulation pathways associated with miR-132 expression. Further research is needed to elucidate the mechanism of each pathway and the potential interplay between multiple proteins regulated by miR-132 that are associated with clinical disorders such as Alzheimer’s disease.