Micro RNA expression in rodent skeletal muscle mitochondria

MiRNAs are non-coding RNAs that regulate gene expression. MiRNAs mostly localise within the cytosol but are also found in the mitochondria where they can regulate the expression of mitochondrial-encoded transcripts. Aberrant miRNA expression is linked to mitochondrial dysfunction in chronic metabolic conditions. However, the role of miRNAs in the regulation of mitochondrial function in healthy tissue, such as in response to endurance exercise training, is not known. The aim of this study was to use a small RNA library preparation approach to profile the entire population of miRNAs in rat skeletal muscle mitochondria and investigate if mitochondrial miRNA expression was altered following4 weeks of endurance training Male Wistar-Kyoto (WKY) rats were obtained from the Australian Resource Centre (Murdoch, WA, Australia) at 4 weeks of age. At 5 weeks of age, the rats were randomly allocated to one of two groups: sedentary (n=12) or endurance trained (n=13). The endurance training protocol consisted of treadmill running 5 days per week for 4-weeks. Sedentary rats were handled identically and were placed on a stationary treadmill for the same amount of time as their trained counterparts during the 4-week training protocol.