Fundamental Neurochemistry Review: At the intersection between the brain and the immune system: Non-coding RNAs spanning learning, memory and adaptive immunity.

Non-coding RNAs (ncRNAs) are highly plastic RNA molecules that can sequester cellular proteins and other RNAs, serve as transporters of cellular cargo and provide spatiotemporal feedback to the genome. Mounting evidence indicates that ncRNAs are central to biology, and are critical for neuronal development, metabolism and intra- and intercellular communication in the brain. Their plasticity arises from state-dependent dynamic structure states that can be influenced by cell type and subcellular environment, which can subsequently enable the same ncRNA with discrete functions in different contexts. Here, we highlight different classes of brain-enriched ncRNAs, including microRNA, long non-coding RNA and other enigmatic ncRNAs, that are functionally important for both learning and memory and adaptive immunity, and describe how they may promote cross-talk between these two evolutionarily ancient biological systems.