Mitochondrial MicroRNAs and Their Potential Role in Cell Function

Mitochondria are cellular powerhouses and central organelles to the regulation of many biological processes, including cell death and metabolism, with mitochondrial dysfunction being a hallmark of many different diseases. MicroRNAs (miRNAs) are a growing class of endogenous non-coding RNAs, which function as master regulators and fine-tuners of the genome, primarily via post-transcriptional mechanisms. miRNAs and RNA interference components have recently been demonstrated to be present in mitochondria from several species. However, miRNA transport mechanisms, biological targets, and function at the mitochondrial level are not well understood, and are only now beginning to emerge. In this review, we describe the biogenesis of miRNAs and present the major findings regarding miRNAs localized to mitochondria, their origin and their putative biological function(s).