In vivo effects of uncoupling protein-3 gene disruption on mitochondrial energy metabolism
In vivo effects of uncoupling protein-3 gene disruption on mitochondrial energy metabolism
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DOI：
10.1074/jbc.m102540200
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发表时间：
2001-06-08
影响因子：
4.8
通讯作者：
Shulman, GI
中科院分区：
文献类型：
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作者：
Cline, GW;Vidal-Puig, AJ;Shulman, GI
为了阐明解偶联蛋白3（UCP 3）在骨骼肌中的作用，我们采用核磁共振和同位素标记实验来评价UCP 3敲除（UCP 3 KO）小鼠体内能量代谢调节的作用。全身能量消耗由双标记的身体水分的周转确定。通过测量ATP合成速率（使用P-31 NMR磁化转移实验）和三羧酸（TCA）循环通量（根据[2-C-13]乙酸盐输注期间谷氨酸盐的C-4和C-2中C-13富集的时间过程计算），评价骨骼肌中线粒体氧化磷酸化的偶联。在全身水平，我观察到能量消耗没有变化。然而，在细胞水平，骨骼肌UCP 3 KO在禁食条件下使从P-i合成ATP的速率增加4倍以上（野生型，2.2 +/-0.6对敲除，9.1 +/-1.4 μ mol/g肌肉/min，p < 0.001），TGA循环通量速率没有变化（野生型，0.74 ± 0.04，而敲除型，0.71 ± 0.03 μ mol/g肌肉/min）。与对照组（4.5 +/-0.4）相比，UCP 3 KO小鼠肌肉中ATP与ADP的比率（5.9 ± 0.3）的显著（p < 0.05）增加可能是由于ATP产生效率的增加。本文提供的数据提供了UCP 3在体内骨骼肌中解偶联活性的第一个证据。
To clarify the role of uncoupling protein-3 (UCP3) in skeletal muscle, we used NMR and isotopic labeling experiments to evaluate the effect of UCP3 knockout (UCP3KO) in mice on the regulation of energy metabolism in vivo. Whole body energy expenditure was determined from the turnover of doubly labeled body water. Coupling of mitochondrial oxidative phosphorylation in skeletal muscle was evaluated from measurements of rates of ATP synthesis (using P-31 NMR magnetization transfer experiments) and tricarboxylic acid (TCA) cycle flux (calculated from the time course of C-13 enrichment in C-4 and C-2 of glutamate during an infusion of [2-C-13]acetate), At the whole body level, me observed no change in energy expenditure. However, at the cellular level, skeletal muscle UCP3KO increased the rate of ATP synthesis from P-i more than 4-fold under fasting conditions (wild type, 2.2 +/- 0.6 versus knockout, 9.1 +/- 1.4 mu mol/g of muscle/min, p < 0.001) with no change in TGA cycle flux rate (wild type, 0.74 0.04 versus knockout, 0.71 +/- 0.03 mu mol/g of muscle/min). The increased efficiency elf ATP production may account for the significant (p < 0.05) increase in the ratio of ATP to ADP in the muscle of UCP3KO mice (5.9 0.3) compared with controls (4.5 +/- 0.4). The data presented here provide the first evidence of uncoupling activity by UCP3 in skeletal muscle in vivo.