Low levels of lipopolysaccharide modulate mitochondrial oxygen consumption in skeletal muscle.
Low levels of lipopolysaccharide modulate mitochondrial oxygen consumption in skeletal muscle.
复制标题
DOI：
10.1016/j.metabol.2014.11.007
复制
发表时间：
2015-03
期刊：
影响因子：
--
通讯作者：
Hulver MW
中科院分区：
文献类型：
--
作者：
Frisard MI;Wu Y;McMillan RP;Voelker KA;Wahlberg KA;Anderson AS;Boutagy N;Resendes K;Ravussin E;Hulver MW
我们以前已经证明，在骨骼肌中的Toll样受体4（TLR 4）的激活导致增加依赖葡萄糖作为能源和伴随的基础条件下脂肪酸氧化的减少。在此，我们研究了脂多糖（LPS），TLR 4的主要配体，在骨骼肌细胞培养和分离的线粒体线粒体的线粒体耗氧量的影响。将骨骼肌细胞培养物暴露于LPS，并使用Seahorse Bioscience细胞外通量分析仪评估氧消耗。小鼠也暴露于LPS，并在从骨骼肌分离的线粒体中评估氧消耗。急性LPS暴露导致C2 C12和人初级肌管中氰化物4-（三氟甲氧基）苯腙（FCCP）刺激的最大呼吸（状态3u）显著减少，寡霉素诱导的状态4（状态4 O）呼吸增加。这些发现与解偶联蛋白3（UCP 3）、超氧化物歧化酶2（SOD 2）和丙酮酸脱氢酶活性的mRNA增加有关。在抗氧化剂N-乙酰半胱氨酸和过氧化氢酶的存在下，LPS介导的底物氧化和最大线粒体呼吸的变化被阻止，这表明活性氧在介导这些效应中的潜在作用。从注射LPS的小鼠的红色腓肠肌和股四头肌中分离的线粒体也表现出呼吸控制率（RCR）降低，以及ADP和FCCP刺激的呼吸。骨骼肌中的LPS暴露改变了线粒体耗氧量和底物偏好，这在抗氧化剂存在时是不存在的。
We have previously demonstrated that activation of toll-like receptor 4 (TLR4) in skeletal muscle results in an increased reliance on glucose as an energy source and a concomitant decrease in fatty acid oxidation under basal conditions. Herein, we examined the effects of lipopolysaccharide (LPS), the primary ligand for TLR4, on mitochondrial oxygen consumption in skeletal muscle cell culture and isolated mitochondria. Skeletal muscle cell cultures were exposed to LPS and oxygen consumption was assessed using a Seahorse Bioscience extracellular flux analyzer. Mice were also exposed to LPS and oxygen consumption was assessed in mitochondria isolated from skeletal muscle. Acute LPS exposure resulted in significant reductions in cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP)-stimulated maximal respiration (state 3u) and increased oligomycin induced state 4 (state 4O) respiration in C2C12 and human primary myotubes. These findings were observed in conjunction with increased mRNA of uncoupling protein 3 (UCP3), superoxide dismutase 2 (SOD2), and pyruvate dehydrogenase activity. The LPS-mediated changes in substrate oxidation and maximal mitochondrial respiration were prevented in the presence of the antioxidants N-acetylcysteine and catalase, suggesting a potential role of reactive oxygen species in mediating these effects. Mitochondria isolated from red gastrocnemius and quadriceps femoris muscle from mice injected with LPS also demonstrated reduced respiratory control ratio (RCR), and ADP- and FCCP-stimulated respiration. LPS exposure in skeletal muscle alters mitochondrial oxygen consumption and substrate preference, which is absent when antioxidants are present.