Nitric oxide and AMPK cooperatively regulate PGC-1α in skeletal muscle cells
Nitric oxide and AMPK cooperatively regulate PGC-1α in skeletal muscle cells
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DOI：
10.1113/jphysiol.2010.194035
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发表时间：
2010-09-15
影响因子：
5.5
通讯作者：
Criswell, David S.
中科院分区：
文献类型：
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作者：
Lira, Vitor A.;Brown, Dana L.;Criswell, David S.
一氧化氮(NO)通过上调过氧化物酶体增殖物激活受体-γ共激活因子1α(PGC-1α)诱导骨骼肌细胞线粒体生物合成。此外，我们还发现一氧化氮与代谢感受器酶AMPK相互作用。因此，我们验证了一氧化氮和AMPK协同作用上调PGC-1αmRNA表达和刺激线粒体生物发生的假说。给予一氧化氮供体S-亚硝基-N-青霉胺(SNAP，25mM)或二乙烯三胺-NONO(DETA-NO，50mU)处理的L6肌管显示AMPK磷酸化、PGC-1α基因和蛋白以及基础和解偶联线粒体呼吸增加(P<；0.05)。用AMPK抑制剂化合物C对培养物进行预处理可以阻止这些影响。用siRNA敲除L6肌管AMPKα1可减少AMPKα蛋白含量，并阻止DETA-NO上调PGC-1αmRNA的表达。同时，下调AMPKα2的siRNA对总AMPKα蛋白含量和PGC-1αmRNA没有影响。这些结果表明，NO对PGC-1α表达的影响是由AMPKα1介导的。矛盾的是，我们发现AMPK激活化合物AICAR诱导L6肌管释放NO，而AICAR诱导的PGC-1α表达上调可被NG-硝基L精氨酸甲酯(L，1 mM)抑制一氧化氮合酶所阻止。此外，分离的小鼠趾长伸肌与2 mM的AICAR孵育20min或电刺激(10 Hz，13V)10min可诱导AMPKα的磷酸化(P<；0.05)，而一氧化氮合酶抑制剂L-NG-单甲基精氨酸(L-NMMA，1 mM)可完全阻止这一作用。这些数据表明，AMPKα1亚型是骨骼肌细胞中NO诱导效应的中介。此外，这项研究支持提出的AMPK和NOS之间协同作用的模型，该模型对于维持骨骼肌细胞的代谢功能至关重要。
Nitric oxide (NO) induces mitochondrial biogenesis in skeletal muscle cells via upregulation of the peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1 alpha). Further, we have shown that nitric oxide interacts with the metabolic sensor enzyme, AMPK. Therefore, we tested the hypothesis that nitric oxide and AMPK act synergistically to upregulate PGC-1 alpha mRNA expression and stimulate mitochondrial biogenesis in culture. L6 myotubes treated with nitric oxide donors, S-nitroso-N-penicillamine (SNAP, 25 mu m) or diethylenetriamine-NONO (DETA-NO, 50 mu m), exhibited elevated AMPK phosphorylation, PGC-1 alpha mRNA and protein, and basal and uncoupled mitochondrial respiration (P < 0.05). Pre-treatment of cultures with the AMPK inhibitor, Compound C, prevented these effects. Knockdown of AMPK alpha 1 in L6 myotubes using siRNA reduced AMPK alpha protein content and prevented upregulation of PGC-1 alpha mRNA by DETA-NO. Meanwhile, siRNA knockdown of AMPK alpha 2 had no effect on total AMPK alpha protein content or PGC-1 alpha mRNA. These results suggest that NO effects on PGC-1 alpha expression are mediated by AMPK alpha 1. Paradoxically, we found that the AMPK-activating compound, AICAR, induced NO release from L6 myotubes, and that AICAR-induced upregulation of PGC-1 alpha mRNA was prevented by inhibition of NOS with NG-nitro-l-arginine methyl ester (l-NAME, 1 mm). Additionally, incubation of isolated mouse extensor digitorum longus (EDL) muscles with 2 mm AICAR for 20 min or electrical stimulation (10 Hz, 13 V) for 10 min induced phosphorylation of AMPK alpha (P < 0.05), which was completely prevented by pre-treatment with the NOS inhibitor, l-NG-monomethyl arginine (l-NMMA, 1 mm). These data identify the AMPK alpha 1 isoform as the mediator of NO-induced effects in skeletal muscle cells. Further, this study supports a proposed model of synergistic interaction between AMPK and NOS that is critical for maintenance of metabolic function in skeletal muscle cells.