From life to death: microRNAs in the fine tuning of the heart

The heart is one of the most important vital organs, and any malfunctioning of the heart and its blood vessels may contribute to cardiovascular disorders. Diseases of the cardiovascular system represent the most common cause of human morbidity and mortality around the globe. Thus, there is always a need for innovative new therapies and diagnostics for cardiovascular disorders. In the past decades, a plethora of tiny, endogenous, single- stranded RNA sequences called microRNAs (miRNAs) has been studied meticulously in cardiovascular development and pathophysiology, providing a new dimension to the heart's biology. miRNAs posttranscriptional inhibit the gene expression of specific mRNA targets through Watson- Crick base pairing between the miRNA "seed region" and the 3' untranslated regions (UTRs) of target mRNAs. Better recognized as "master switches", miRNAs are emerging as vital regulators of mammalian cardiovascular development and disease and thus are helpful in understanding therapeutic targets and diagnostics for a variety of cardiovascular disorders. In this review, a detailed discussion of the roles of various microRNAs in cardiovascular development and pathophysiology with potential therapeutics is considered.