TY - JOUR
T1 - Changes in IL-15 expression and death-receptor apoptotic signaling in rat gastrocnemius muscle with aging and life-long calorie restriction
AU - Marzetti, Emanuele
AU - Carter, Christy S.
AU - Wohlgemuth, Stephanie E.
AU - Lees, Hazel A.
AU - Giovannini, Silvia
AU - Anderson, Barbara
AU - Quinn, Lebris S.
AU - Leeuwenburgh, Christiaan
PY - 2009
Y1 - 2009
N2 - TNF-α-mediated apoptosis is enhanced in aged rodent muscles, suggesting that this pathway may be involved in sarcopenia. Interleukin-15 (IL-15), a muscle-derived anabolic cytokine, mitigates muscle wasting and apoptosis in cachectic rats. This effect is thought to occur through inhibition of TNF-α-triggered apoptosis. We investigated IL-15 signaling and the TNF-α-mediated pathway of apoptosis in the gastrocnemius muscle of Fischer344xBrown Norway rats across the ages of 8, 18, 29 and 37 months, in relation to life-long calorie restriction (CR, 40% calorie intake reduction). Aging caused loss of muscle mass and increased apoptotic DNA fragmentation, which were mitigated by CR. Protein levels of IL-15 and mRNA abundance of IL-15 receptor α-chain decreased in senescent ad libitum (AL) fed rats, but were maintained in CR rodents. Elevations of TNF-α, TNF-receptor 1, cleaved caspase-8 and -3 were observed at advanced age in AL rats. These changes were prevented or mitigated by CR. Our results indicate that aging is associated with decreased IL-15 signaling in rat gastrocnemius muscle, which may contribute to sarcopenia partly through enhanced TNF-α-mediated apoptosis. Preservation of IL-15 signaling by CR may therefore represent a further mechanism contributing to the anti-aging effect of this dietary intervention in skeletal muscle.
AB - TNF-α-mediated apoptosis is enhanced in aged rodent muscles, suggesting that this pathway may be involved in sarcopenia. Interleukin-15 (IL-15), a muscle-derived anabolic cytokine, mitigates muscle wasting and apoptosis in cachectic rats. This effect is thought to occur through inhibition of TNF-α-triggered apoptosis. We investigated IL-15 signaling and the TNF-α-mediated pathway of apoptosis in the gastrocnemius muscle of Fischer344xBrown Norway rats across the ages of 8, 18, 29 and 37 months, in relation to life-long calorie restriction (CR, 40% calorie intake reduction). Aging caused loss of muscle mass and increased apoptotic DNA fragmentation, which were mitigated by CR. Protein levels of IL-15 and mRNA abundance of IL-15 receptor α-chain decreased in senescent ad libitum (AL) fed rats, but were maintained in CR rodents. Elevations of TNF-α, TNF-receptor 1, cleaved caspase-8 and -3 were observed at advanced age in AL rats. These changes were prevented or mitigated by CR. Our results indicate that aging is associated with decreased IL-15 signaling in rat gastrocnemius muscle, which may contribute to sarcopenia partly through enhanced TNF-α-mediated apoptosis. Preservation of IL-15 signaling by CR may therefore represent a further mechanism contributing to the anti-aging effect of this dietary intervention in skeletal muscle.
KW - Apoptosis
KW - Calorie restriction
KW - Interleukin-15
KW - Sarcopenia
KW - Tumor necrosis factor-α
KW - Apoptosis
KW - Calorie restriction
KW - Interleukin-15
KW - Sarcopenia
KW - Tumor necrosis factor-α
UR - http://hdl.handle.net/10807/221844
U2 - 10.1016/j.mad.2008.12.008
DO - 10.1016/j.mad.2008.12.008
M3 - Article
SN - 0047-6374
VL - 130
SP - 272
EP - 280
JO - Mechanisms of Ageing and Development
JF - Mechanisms of Ageing and Development
ER -