TY - JOUR
T1 - Exercise training attenuates aging-associated mitochondrial dysfunction in rat skeletal muscle
T2 - Role of PGC-1α
AU - Kang, Chounghun
AU - Chung, Eunhee
AU - Diffee, Gary
AU - Ji, Li Li
N1 - Funding Information:
This research was supported by a grant from the Wisconsin Alumni Research Foundation (WARF) and the NIH/NIA Aged Rodent Research Program .
PY - 2013/11
Y1 - 2013/11
N2 - Aged skeletal muscle demonstrates declines in muscle mass and deterioration of mitochondrial content and function. Peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) plays an important role in promoting muscle mitochondrial biogenesis in response to exercise training, but its role in senescent muscle is not clear. In the present study we hypothesize that a downregulation of the PGC-1α signaling pathway contributes to mitochondrial deterioration in aged muscle whereas endurance training ameliorates the deficits. Three groups of Fischer 344/BNF1 rats were used: young, sedentary (Y, 4. months); old, sedentary (O, 22. months); and old trained (OT, 22. months), subjected to treadmill running at 17.5. m/min, 10% grade for 45. min/day, 5. days/week for 12-weeks. PGC-1α mRNA and nuclear PGC-1α protein content in the soleus muscle were both decreased in O vs. Y rats, whereas OT rats showed a 2.3 and 1.8-fold higher PGC-1α content than O and Y rats, respectively (P. <. 0.01). Mitochondrial transcription factor A (Tfam), cytochrome c (Cyt c) and mitochondrial (mt) DNA contents were significantly decreased in O vs. Y rats, but elevated by 2.2 (P. <. 0.01), 1.4 (P. <. 0.05) and 2.4-fold (P. <. 0.01), respectively, in OT vs. O rats. In addition, Tfam and mtDNA showed 1.6 and 1.8-fold (P. <. 0.01) higher levels, respectively, in OT vs. Y rats. These adaptations were accompanied by significant increases in the expression of the phosphorylated form of AMP-activated kinase (AMPK) (P. <. 0.01), p38 mitogen-activated kinase (MAPK) (P. <. 0.05) and silent mating type information regulator 2 homolog 1 (SIRT1) (P. <. 0.01) in OT rats. Furthermore, OT rats showed great levels of phosphorylation in cAMP responsive element binding protein (p-CREB) and DNA binding compared to O and Y rats. These data indicate that endurance training can attenuate aging-associated decline in mitochondrial protein synthesis in skeletal muscle partly due to upregulation of PGC-1α signaling.
AB - Aged skeletal muscle demonstrates declines in muscle mass and deterioration of mitochondrial content and function. Peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) plays an important role in promoting muscle mitochondrial biogenesis in response to exercise training, but its role in senescent muscle is not clear. In the present study we hypothesize that a downregulation of the PGC-1α signaling pathway contributes to mitochondrial deterioration in aged muscle whereas endurance training ameliorates the deficits. Three groups of Fischer 344/BNF1 rats were used: young, sedentary (Y, 4. months); old, sedentary (O, 22. months); and old trained (OT, 22. months), subjected to treadmill running at 17.5. m/min, 10% grade for 45. min/day, 5. days/week for 12-weeks. PGC-1α mRNA and nuclear PGC-1α protein content in the soleus muscle were both decreased in O vs. Y rats, whereas OT rats showed a 2.3 and 1.8-fold higher PGC-1α content than O and Y rats, respectively (P. <. 0.01). Mitochondrial transcription factor A (Tfam), cytochrome c (Cyt c) and mitochondrial (mt) DNA contents were significantly decreased in O vs. Y rats, but elevated by 2.2 (P. <. 0.01), 1.4 (P. <. 0.05) and 2.4-fold (P. <. 0.01), respectively, in OT vs. O rats. In addition, Tfam and mtDNA showed 1.6 and 1.8-fold (P. <. 0.01) higher levels, respectively, in OT vs. Y rats. These adaptations were accompanied by significant increases in the expression of the phosphorylated form of AMP-activated kinase (AMPK) (P. <. 0.01), p38 mitogen-activated kinase (MAPK) (P. <. 0.05) and silent mating type information regulator 2 homolog 1 (SIRT1) (P. <. 0.01) in OT rats. Furthermore, OT rats showed great levels of phosphorylation in cAMP responsive element binding protein (p-CREB) and DNA binding compared to O and Y rats. These data indicate that endurance training can attenuate aging-associated decline in mitochondrial protein synthesis in skeletal muscle partly due to upregulation of PGC-1α signaling.
KW - Aging
KW - Exercise
KW - Mitochondria
KW - PGC-1α
KW - Skeletal muscle
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U2 - 10.1016/j.exger.2013.08.004
DO - 10.1016/j.exger.2013.08.004
M3 - Article
C2 - 23994518
AN - SCOPUS:84884547174
SN - 0531-5565
VL - 48
SP - 1343
EP - 1350
JO - Experimental Gerontology
JF - Experimental Gerontology
IS - 11
ER -