MicroRNAs in Neurodegenerative Disorders

MicroRNAs (miRNAs) are a class of small, noncoding RNAs (21–23 nucleotides in length) that can downregulate gene expression at the posttranscriptional level by either degrading or blocking the translation of messenger RNA targets. MicroRNAs are enriched in the brain and expressed in a spatially and temporally controlled manner. They play a key role in neuronal development, differentiation, biochemical pathways, and synaptic plasticity, and their expression is also tightly regulated. Mounting evidence shows that aberrant expression and dysfunction of brain-enriched microRNAs could be involved in the molecular pathogenesis of neurodegenerative disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS). Here, we review recent research into aberrant miRNA expression in neurodegenerative disorders.