Diversity and Differential Expression of microRNAs in the Human Skeletal Muscle with Distinct Fiber Type Composition

The ratio of fast- and slow-twitch fibers in human skeletal muscle tissue is variable and largely determined by genetic factors. In this study we investigated the contribution of miRNAs in skeletal muscle fiber type composition. The study involved biopsy samples of the vastus lateralis muscle from ten male athletes under the age of 40 years from two groups: five endurance athletes (stayers) with the predominance of slow-twitch fibers, and five power athletes or sprinters with the predominance of fast-twitch fibers. Small RNA was extracted from tissue samples. Small RNA sequencing showed that miRNA profiles differed between the sample groups.