Approaches to Studying the microRNAome in Skeletal Muscle

Muscle is a highly plastic tissue that needs to rapidly undergo dramatic changes in gene expression patterns in order to maintain homeostasis. This requires a delicate balance between satellite cell proliferation, myotube formation and differentiation, and muscle degeneration/regeneration. The disruption of these pathways drives muscle disorders and diseases; this includes dystrophies, inflammatory myopathies, sarcopenia, and cachexia. Thus, identifying factors that regulate muscle gene expression programs is essential to understanding muscle health and function and may uncover new therapeutic targets. Since the discovery of microRNAs (miRNAs), it has become well established that they are key regulatory factors which fine-tune gene expression patterns in all cell and tissue types. As we gain new insight into the function of miRNAs, their essential role as posttranscriptional regulatory elements that drive proper muscle function becomes increasingly apparent. As has been observed in the X-linked genetic diseases Duchenne and Becker muscular dystrophies (DMD and BMD, respectively), the chronic dysregulation of miRNAs can exacerbate disease. In this chapter we will explore the role of miRNAs in skeletal muscle and the importance of harnessing the power of miRNA profiling to understand how different perturbations to muscle (i.e. exercise, injury, or genetic defects) affect the muscle miRNAome and how the miRNAome, in turn, can yield valuable information about the overall health of muscle.