A microRNA (abbreviated miRNA) is a small non-coding RNA molecule (containing about 22 nucleotides) found in plants, animals, and some viruses. Key findings:
miRNA is involved in the normal functioning of eukaryotic cells, so has dysregulation of miRNA been associated with disease - review http://www.mir2disease.org/
The first human disease known to be associated with miRNA deregulation was chronic lymphocytic leukemia. Many miRNAs have subsequently been found to have links with various types of cancer and accordingly are sometimes referred to as "oncomirs".
The global role of miRNA function in the heart has been addressed by conditionally inhibiting miRNA maturation in the murine heart and has revealed that miRNAs play an essential role during its development.
miRNAs appear to regulate the development and function of the nervous system. Some studies find altered miRNA expression in schizophrenia, as well as bipolar disorder, and major depression and anxiety disorders.
miRNAs in gene expression is significant to addiction, specifically alcoholism.
Another class of miRNAs that regulate insulin resistance, obesity, and diabetes.
miRNAs can bind to target messenger RNA (mRNA) transcripts of protein-coding genes and negatively control their translation or cause mRNA degradation.