present study was proposed to study assays for plasma miRNA-206 and progress of
basketball skills to determine the effects of a training basketball program
undergone through twelve successive weeks. Also, to investigate cell metabolism
after strenuous exercise.
significant increase in plasma miRNA 206 after exercise and its resistance
elevation after about 12 weeks of training suggests that miRNA-206 could
possibly be an important tool for monitoring and quantification of cellular adaptation.
This study comprised
three main results; the first is the increased 1.13 fold elevation of plasma
miRNA-206 after acute exhausting exercise, the second is more increased
elevation of miRNA-256 up to 1.39 fold due to the basketball training program
and third is the developed skills due to program. These observations suggest a
potential role for c-miRNAs as biomarkers of exercise physiology and provide
novel insight into the potential regulatory role of c-miRNAin the myriad
physiological processes that accompany exercise.
Results from Baggish
et al. (2011) study assure these findings as they reported significant
changes in circulating miRNAs in response to exercise and demonstrated
that these changes may occur in response either to a single acute bout of
exhaustive exercise or to sustained exercise training. Thus, these molecules
appear integrally linked to both the initial stresses and the longer term adaptations
that are characteristic of exercise.
up-regulation after chronic exercise training may rely upon modulation
of either transcriptional or post-transcriptional processing of intracellular miRNA.
Non-specific release of miRNA from peripheral muscle tissue may also contribute
to increases in circulating miRNA (c-miRNA) levels, as strenuous and/or
eccentric aerobic exercise can acutely cause microscopic damage to muscle cells
Several miRNAs are
highly regulated in vivo and in vitro during muscle development and, in turn, regulate
muscle differentiation (Baggish et al., 2011). The most-studied
miRNAs are miR-133a/b, miR-206, and miR-1, which are induced during
differentiation of myoblasts into myotubes (Proske and Allen, 2005) and
are collectively referred to as the “myomirs.” The myomirs, which are also
highly expressed in vivo, may also be regulated during changes in muscle
phenotype (Davidsen et al., 2011).
Upon transfection in
the continued presence of serum, miR- 206 markedly up-regulated the percentage
of cells expressing myosin heavy chain (MHC) and the muscle-specific
transcription factor myogenin. In addition, 28% of MHC positive cells are
multinucleated after miR-206 treatment, whereas no multinucleated cells were
detected in miR-206 absent control. Therefore, physiological levels of miR-206
induce skeletal myogenesis (Kim et al., 2006).
It appears that
myomiRs may be associated with muscle growth and regeneration (Chen et
al. 2006; Nakasa et al. 2009), implicating a potential role in
skeletal muscle adaptation to exercise. Indeed, myomiR expression is acutely
altered during post-exercise recovery in humans and rats (Drummond et al.
2008; Safdar et al. 2009) while models of muscle overload can significantly
alter myomiR expression to new steady state levels (McCarthy & Esser, 2007).