MicroRNAs and their antagonists as novel therapeutics

During the past decade, it has been realized that microRNAs (miRNAs) regulate expression of about half of human genes and thereby act as key mediators of most pathways involved in human health and disease. Given that miRNAs are often deregulated in disease processes, it comes as no surprise that therapeutic targeting of miRNA expression and function is a subject of intense investigation. Recently, the field has seen considerable progress, and the first miRNA drugs, in the form of miRNA antagonists, have entered clinical trials. In this chapter we will (1) explore how miRNAs function in health and how they change during disease development, focusing on the mode of miRNA regulation (often, this involves moderate control of many targets); (2) describe the strategies used to manipulate miRNA expression and the challenges associated in a clinical setting; (3) provide an overview of miRNAs and their antagonists as therapeutics; and (4) finally, discuss the therapeutic potential of miRNA manipulation and the caveats that come with it.