| First Author | Boppart MD | Year | 2008 |
| Journal | Am J Physiol Regul Integr Comp Physiol | Volume | 295 |
| Issue | 5 | Pages | R1623-30 |
| PubMed ID | 18784336 | Mgi Jnum | J:148634 |
| Mgi Id | MGI:3846008 | Doi | 10.1152/ajpregu.00089.2008 |
| Citation | Boppart MD, et al. (2008) Exercise promotes alpha7 integrin gene transcription and protection of skeletal muscle. Am J Physiol Regul Integr Comp Physiol 295(5):R1623-30 |
| abstractText | The alpha7beta1 integrin is increased in skeletal muscle in response to injury-producing exercise, and transgenic overexpression of this integrin in mice protects against exercise-induced muscle damage. The present study investigates whether the increase in the alpha7beta1 integrin observed in wild-type mice in response to exercise is due to transcriptional regulation and examines whether mobilization of the integrin at the myotendinous junction (MTJ) is a key determinant in its protection against damage. A single bout of downhill running exercise selectively increased transcription of the alpha7 integrin gene in 5-wk-old wild-type mice 3 h postexercise, and an increased alpha7 chain was detected in muscle sarcolemma adjacent to tendinous tissue immediately following exercise. The alpha7B, but not alpha7A isoform, was found concentrated and colocalized with tenascin-C in muscle fibers lining the MTJ. To further validate the importance of the integrin in the protection against muscle damage following exercise, muscle injury was quantified in alpha7(-/-) mice. Muscle damage was extensive in alpha7(-/-) mice in response to both a single and repeated bouts of exercise and was largely restricted to areas of high MTJ concentration and high mechanical force near the Achilles tendon. These results suggest that exercise-induced muscle injury selectively increases transcription of the alpha7 integrin gene and promotes a rapid change in the alpha7beta integrin at the MTJ. These combined molecular and cellular alterations are likely responsible for integrin-mediated attenuation of exercise-induced muscle damage. |
