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1 Medical Sciences, McMaster University, Hamilton, Canada
2 Kinesiology, McMaster University, Hamilton, Canada
3 Buck Institute for Age Research, Novato, California, United States
4 Neuromuscular Disease Unit, Departments of Pediatrics and Medicine, McMaster University, Hamilton, Canada
* To whom correspondence should be addressed. E-mail: tarnopol{at}mcmaster.ca.
We used cDNA microarrays to screen for differentially expressed genes during recovery from exercise-induced muscle damage in humans. Male subjects (n = 4) performed 300 maximal eccentric contractions, and skeletal muscle biopsy samples were analyzed at 3 h and 48 h after exercise. In total, 113 genes increased 3 h post exercise, and 34 decreased. At 48 h post-exercise, 59 genes increased and 29 decreased. Based on these data, we chose 19 gene changes and conducted secondary analyses using real-time RT-PCR, from muscle biopsy samples taken from 11 additional subjects who performed an identical bout of exercise. Real-time RT-PCR analyses confirmed that exercise-induced muscle damage led to a rapid (3 h) increase in sterol response element binding protein 2 (SREBP-2), followed by a delayed (48 h) increase in the SREBP-2 gene targets Acyl CoA:cholesterol acyltransferase (ACAT)-2 and insulin induced gene 1 (insig-1). The expression of the IL-1 receptor, a known regulator of SREBP-2, was also elevated after exercise. Taken together, these expression changes suggest a transcriptional program for increasing cholesterol and lipid synthesis and/or modification. Additionally, damaging exercise induced the expression of protein kinase H11, capping protein Z alpha (capZ
), and modulatory calcineurin-interacting protein 1 (MCIP1), as well as cardiac ankryin repeat protein 1 (CARP1), DNAJB2, c-myc, and junD, each of which are likely involved in skeletal muscle growth, remodeling, and stress management. In summary, we have identified novel genes that respond to skeletal muscle damage, which are likely involved in recovery from and/or adaptation to damaging exercise.
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