Figure 1.

Scheme of oligonucleotide-based RNA delivery. A, AntimiRs (miRNA inhibitors) can be modified with different chemical modifications, including locked nucleic acids (LNAs) and sugar backbone modifications (2’-O-Me, 2’-F/MOE, and 2’-O-MOE), while miRNA can also be enhanced via miRNA mimics. To inhibit mRNAs or long noncoding RNAs (lncRNAs), short hairpin RNAs (shRNAs), or LNA/GapmeR are commonly used. B, Adenovirus, adenoassociated virus (AAV), and lentivirus particles can be used as a vector to silence or overexpress target genes. In addition to viral-based delivery, liposomes or nanoparticles are another way through which to deliver antimiRs or miRNA mimics. C, Various delivery approaches can be applied in different species. For example, atrium injection is performed in rabbits and dogs with atrial fibrillation. For pigs, intravenous injection, catheter-based injection, and intracoronary injection are commonly used. Subcutaneous injection can be also used. Clinically, subcutaneous injection, intravenous injection, and intradermal injection are more attractive and easier delivery routes in humans.