MicroRNA molecules, master regulators, biomarkers, and potential therapies

Abstract

A group of small noncoding RNAs-known as microRNAs-are master posttranscriptional regulators of cellular processes during specification and also preserve tissue homeostasis in adults. Most of the microRNA molecules (miRNAs) are tissue and stage specific, so that patterns of miRNA expression can be useful biomarkers in neoplastic, degenerative, and inflammatory diseases. Environmental factors have a great impact on the pathogenesis of rheumatic diseases, due to their ability to induce epigenetic modifications in gene expression patterns. A common vehicle of exogenously induced epigenetic modifications is oxidative stress. A number of miRNA are induced by redox-sensitive transcription factors and/or by epigenetic modifications. These miRNAs participate in the cellular response to oxidative stress either by protecting cells or promoting damage. In this sense, high-throughput miRNA expression studies can identify miRNA signatures that will help assess the risk of oxidative stress-dependent damage in defined cell populations. Importantly, a single miRNA can regulate an entire molecular pathway through the binding and translational inhibition of several end products. Furthermore, some miRNAs control the activity of transcriptional regulators. This ability makes miRNA attractive as therapeutic agents, an emerging field that is starting to be explored.