Since their discovery a little over 20 years ago, miRNAs have emerged as an exciting and promising research and applied science target due to their involvement in many important cellular processes and their clear links to disease states. Bioline has developed a range of products to support miRNA research, including a range of expertly designed qPCR panels for analyzing important miRNAs in the areas of cancer, stem cells and biofluid analysis.
Studies in the human genome have seen dysfunction in miRNA regulation linked to many different disease states and research continues in attempts to unravel the complex ways in which miRNAs interact with other genetic elements affecting gene expression on a number of different levels.
The most studied mechanism of miRNA mediated gene regulation involves the mature miRNA and an RNA-induced silencing complex, this miRNA-RISC complex then binds to mRNA leading to degradation or translation inhibition. Each miRNA has the potential to target a number of different genes, plus research has also demonstrated ribonucleoprotein binding in a RISC-independent manner, as well as direct binding to DNA.1 Thus the regulation of gene expression by miRNAs is a complex and multi-level phenomenon.
It is not a straight forward practice, however, as qPCR analysis of miRNAs requires a number of challenges to be overcome including:
Deep sequencing using next generation sequencing (NGS) platforms is another popular method for profiling miRNA populations and, more importantly, identifying and discovering novel miRNAs. NGS technologies typically produce read lengths compatible with the length of mature miRNAs and the direct transcript count allows for determination of expression levels based on abundance.
The connection between specific miRNAs and disease state is not surprising, given the clearly important role they play in most cellular processes and studies have now shown tissue-specific miRNA expression profiles that directly link to the physiological state of the originating cell. Moreover, comprehensive miRNA expression profiling has identified disease-specific expression patterns reflecting the lineage and differentiation status of various cancers. Thus miRNA-based research holds significant promise in the applications of prognostic and diagnostic oncology and many other therapeutic areas.
miRNAs have been classified as oncogenes, with a demonstrated role in the negative regulation of tumor suppressor genes, as well as controlling cellular differentiation, proliferation and survival. Found in a range of different biological fluids including plasma, serum and saliva, miRNAs exhibit excellent stability thanks to their small size and presence within microvesicles, as well as other potential mechanisms that protect them from the degradation that often affects other circulating RNA.
1. Iorio MV & Croce CM. MicroRNA dysregulation in cancer: diagnostics, monitoring and therapeutics. A comprehensive review. EMBO Mol Med 2012:4(3);143-159.