The Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin at Madison, Madison, WI 53706, USA.
Free Radic Biol Med. 2009 Nov 15;47(10):1394-400. doi: 10.1016/j.freeradbiomed.2009.08.007. Epub 2009 Aug 14.
The peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha)-activated signal transduction pathway has previously been shown to stimulate mitochondrial biogenesis in skeletal muscle in response to endurance exercise. In vitro data indicate that PGC-1alpha signaling may be sensitive to reactive oxygen species (ROS) but its role in vivo is not clear. The objectives of this study were (1) to investigate whether the PGC-1alpha pathway could be activated by a single bout of anaerobic exercise in rats, wherein a major portion of ROS was generated via the cytosolic xanthine oxidase (XO), and (2) to examine whether allopurinol (ALP), a specific XO inhibitor, would attenuate PGC-1alpha expression and signaling owing to decreased ROS generation. Female Sprague-Dawley rats were randomly divided into three groups: (1) subjected to sprinting on a treadmill at 35 m/min, 15% grade, for 3 min followed by 3 min slow running at 15 m/min, 0% grade, repeated until exhaustion (88 +/- 4 min; Exer; N= 9); (2) subjected to the same exercise protocol (88 +/- 4 min) but injected with two doses of ALP (0.4 mmol/kg, ip) 24 and 1 h before the experiment (Exer+ ALP; N= 9); and (3) rested control (C; N= 9). Exercise increased XO activity and ROS generation in the Exer rat vastus lateralis muscle (P< 0.05), whereas the Exer+ ALP group displayed only 7% XO activity and similar ROS level compared with the C group. PGC-1alpha protein content showed a 5.6-fold increase (P< 0.01) in Exer vs C, along with a 200% (P< 0.01) increase in both nuclear respiratory factor (NRF)-1 and mitochondrial transcription factor A (Tfam) content. ALP treatment decreased PGC-1alpha, NRF-1, and Tfam levels by 45, 19, and 20% (P< 0.05), respectively. Exercise doubled the content of the phosphorylated cAMP-responsive element-binding protein in the Exer group (P< 0.01) and tripled phosphorylated p38 mitogen-activated protein kinase (P< 0.01), whereas these effects were reduced by 60 and 30% (P< 0.01, P< 0.05), respectively, in Exer+ ALP rats. Nuclear factor-kappaB binding and phospho-IkappaB content were also increased in Exer rats (P< 0.01) and these increases were abolished by ALP treatment. The data indicate that contraction-activated PGC-1alpha signaling pathways in skeletal muscle are redox sensitive and that nonmitochondrial ROS play an important role in stimulating mitochondrial biogenesis.
过氧化物酶体增殖物激活受体-γ共激活因子 1α（PGC-1α）激活的信号转导途径先前已被证明可在耐力运动中刺激骨骼肌中的线粒体生物发生。体外数据表明，PGC-1α信号可能对活性氧物种（ROS）敏感，但在体内的作用尚不清楚。本研究的目的是：（1）研究大鼠单次无氧运动是否可以激活 PGC-1α 途径，其中大部分 ROS 通过胞质黄嘌呤氧化酶（XO）产生；（2）研究别嘌呤醇（ALP）是否可以抑制 PGC-1α 表达和信号传导，因为它会降低 ROS 的产生。将雌性 Sprague-Dawley 大鼠随机分为三组：（1）在 35 m/min、15%坡度的跑步机上进行短跑，持续 3 分钟，然后以 15 m/min、0%坡度进行 3 分钟慢跑，直到力竭（88 +/- 4 分钟；Exer；N=9）；（2）进行相同的运动方案（88 +/- 4 分钟），但在实验前 24 和 1 小时注射两剂 ALP（0.4 mmol/kg，ip）（Exer+ALP；N=9）；和（3）休息对照（C；N=9）。运动增加了 Exer 大鼠股外侧肌中的 XO 活性和 ROS 生成（P<0.05），而 Exer+ALP 组与 C 组相比，XO 活性仅为 7%，ROS 水平相似。PGC-1α 蛋白含量在 Exer 中增加了 5.6 倍（P<0.01），同时核呼吸因子（NRF）-1 和线粒体转录因子 A（Tfam）的含量增加了 200%（P<0.01）。ALP 处理使 PGC-1α、NRF-1 和 Tfam 的水平分别降低了 45%、19%和 20%（P<0.05）。运动使 Exer 组的磷酸化 cAMP 反应元件结合蛋白含量增加了一倍（P<0.01），并使磷酸化 p38 丝裂原活化蛋白激酶（p38 MAPK）增加了两倍（P<0.01），而 Exer+ALP 大鼠中的这些作用分别降低了 60%和 30%（P<0.01，P<0.05）。NF-κB 结合和磷酸化 IkappaB 含量也在 Exer 大鼠中增加（P<0.01），而 ALP 处理则消除了这些增加。数据表明，骨骼肌中收缩激活的 PGC-1α 信号通路对氧化还原敏感，并且非线粒体 ROS 在刺激线粒体生物发生中起重要作用。
