Targeting of microRNAs that are overexpressed or replacement of microRNAs whose expression is lost are two distinct and novel approaches to treat disease(s) driven by microRNA dysregulation. This can be achieved by chemical modification of either a single stranded oligonucleotide called an anti-miR or a double stranded nucleic acid molecule termed a microRNA mimic. With hundreds of microRNAs identified and knowledge of their role in disease becoming clearer there is the prospect, over the coming years, to harness engineered microRNA therapeutics to revolutionise the way diseases are treated. Both types of engineered microRNA therapeutics have advanced into clinical development with human proof of concept achieved with an anti-miR targeting miR-122 (one of the most abundant microRNAs in human hepatocytes that is utilised by the hepatitis C virus to enable its function and replication). Rather than targeting individual proteins or enzymes involved in human disease, an opportunity now exists to modulate multiple different proteins/enzymes which act in concert in the progression of disease.
