microRNAs in Brain Endothelium and Inflammation

Blood-brain barrier (BBB) dysfunction, characterised by increased permeability across brain endothelium and/or leukocyte extravasation into CNS tissue, is associated with changes in the gene expression profile of brain endothelium and is therefore potentially controlled by epigenetic factors. MicroRNAs (miRNAs) are single-stranded, short, non-coding RNA molecules that mediate post-transcriptional gene silencing. Recent studies have demonstrated alterations of miRNA expression at the BBB in experimental autoimmune encephalomyelitis, in multiple sclerosis, and in cytokine-stimulated human brain endothelial cells. These results suggest that brain endothelial miRNAs play a role in the pathophysiology of the BBB in inflammation. In this chapter, we will first give an overview of miRNA biology and then review the current knowledge of the role of miRNAs in regulating BBB function, particularly in the context of multiple sclerosis.