Therapeutic potential of RNA interference in pain medicine.

In recent years RNA interference (RNAi) has rapidly become the most widely used tool for gene knockdown due to its high specificity and potency. RNAi is an evolutionarily conserved mechanism for silencing gene expression by targeted degradation of mRNA. In the past decade, hundreds of molecular targets have been identified for their roles in pain modulation. But most molecular targets are not readily druggable with small molecules. RNAi represents a therapeutic approach applicable to these non-druggable targets. There is a rapid increase in the number of studies that use small interfering RNAs (siRNAs) to validate new targets for pain regulation. In this review, we will discuss these pain-related RNAi studies (Table 1). We will also compare the advantages and disadvantages of RNAi with antisense knockdown (Table 2), because antisense oligodeoxynucleotides have been extensively used for target validation in pain research. Although in vivo delivery of siRNA remains to be a challenge, RNAi has a great potential to become a major therapeutic tool for pain management.