MicroRNA (miRNA) (miRNA)

MicroRNAs (miRNAs) are a class of small, single-stranded non-coding RNA molecules, typically 21 to 25 nucleotides in length, that serve as critical post-transcriptional regulators of gene expression. They function as guides for the RNA-induced silencing complex (RISC), targeting specific messenger RNAs (mRNAs) for degradation or translational inhibition, thereby modulating vast networks of genes involved in cell growth, differentiation, and survival. Dysregulation of miRNA expression is a common feature in numerous human diseases, particularly cancer, where they can act as either oncogenes (oncomiRs) or tumor suppressors. In the context of drug development, miRNAs are treated both as therapeutic agents and as targets for inhibition. 'MicroRNA delivery' refers to the complex technological challenge of transporting these unstable nucleic acids into specific target cells while avoiding nuclease degradation and immune detection. Therapeutic interventions utilize miRNA mimics to replenish deficient levels of protective RNAs or antagomirs (antisense oligonucleotides) to neutralize disease-associated miRNAs. Despite their promise for treating 'undruggable' targets, the clinical advancement of miRNA-based therapies is heavily dependent on the development of specialized delivery systems, such as lipid nanoparticles and viral vectors, to ensure systemic stability and minimize off-target toxicity.

Other names

miRMicro-RNASmall non-coding RNAmiRNA mimicAntagomirAntimiR

MicroRNAs function by binding to complementary sequences on the 3' untranslated regions (UTRs) of target messenger RNAs (mRNAs), leading to mRNA degradation or translational repression. Therapeutic strategies include miRNA replacement therapy using synthetic mimics to restore lost tumor-suppressive functions and miRNA inhibition therapy using antisense oligonucleotides (antagomirs) to block the activity of overexpressed oncogenic microRNAs (oncomiRs).