MicroRNAs Role in the Central Nervous System Development and Abnormalities

Initially, non-coding RNAs were thought to be “junk RNAs”. MicroRNAs (miRNAs), a group of small non-coding RNA molecules, were discovered in 1993. However, their functions have been found to be associated with diverse biological procedures, including development, metabolism, immunity, hematopoietic differentiation, etc.It is estimated that miRNAs regulate theactivity of approximately 60% of human protein-coding genes. Abnormal miRNA expression may lead to a number of diseases, such as neoplasms, age-related diseases, and neurological disorders. Advances in miRNA research have suggested that miRNAs not only help to understand molecular mechanisms of human CNS diseases, but also have potential to serve as biomarkers for early detection of neurological and/or neurodegenerative alterations.

Around 70% of the identified miRNAs are found in the brain. Some miRNAs are specifically expressed and enriched in brain , suggesting their specific roles in regulating brain functions. Specifically, miRNAs are implicated in brain development: they regulate embryonic neuralinduction, development, differentiation, neuronal subtype specification,migration and integration, synaptogenesis and synaptic plasticity. Any interference of miRNA regulations may be associated with aberrant neural development and neurological disorders.