MicroRNAs (miRNAs) — 21- to 23-nucleotide single-stranded RNAs that regulate gene expression — have roles in numerous diseases, and are therefore attractive therapeutic targets. Li and Rana discuss strategies in the design of miRNA-targeting oligonucleotides with increased efficacy and improvedin vivodelivery characteristics, and highlight some of the challenges that lie ahead in the clinical development of these therapeutics.
