¹³C magnetic resonance spectroscopy detection of changes in serine isotopomers reflects changes in mitochondrial redox status.
¹³C magnetic resonance spectroscopy detection of changes in serine isotopomers reflects changes in mitochondrial redox status.
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13C磁共振波谱检测丝氨酸同位素的变化反映了线粒体氧化还原状态的变化。
DOI：
10.1002/mrm.23296
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发表时间：
2012
影响因子：
3.3
通讯作者：
Macdonald,JeffreyM
中科院分区：
文献类型：
--
作者：
Johnson,CBryce;Tikunov,AndreyP;Lee,Haakil;Wolak,JustynaE;Pediaditakis,Peter;Romney,DougA;Holmuhamedov,Ekhson;Gamcsik,MichaelP;Macdonald,JeffreyM
甘氨酸裂解系统（glycine cleavage system，GCS）是肝脏中甘氨酸催化的主要途径，仅存在于线粒体基质中，并受氧化型烟酰胺腺嘌呤二核苷酸（nicotinamide adenine dinucleotide，NAD+）/还原型烟酰胺腺嘌呤二核苷酸（nicotinamide adenine dinucleotide，NADH）比率的调节。甘氨酸与丝氨酸羟甲基转移酶一起形成丝氨酸的1位和2位，而3位仅由GCS形成。因此，我们试图利用这一途径来表明，在肝脏中的丝氨酸同位素的定量测量可用于监测NAD+/NADH比率使用13 C NMR光谱。用GCS活性调节剂处理大鼠肝细胞，然后加入2 - 13 C-甘氨酸，并将新合成的丝氨酸同位素异构体比例的变化与对照组进行比较。半胱胺是GCS的竞争性抑制剂，它阻止了线粒体3 - 13 C-丝氨酸和2，3 - 13 C-丝氨酸同位素异构体的形成，同时减少了55%的2 - 13 C-丝氨酸，表明这种抑制剂可以抑制线粒体3 - 13 C-丝氨酸和2，3 - 13 C-丝氨酸同位素异构体的形成。20%的甘氨酸衍生的丝氨酸在胞质溶胶中产生。激活GCS活性的胰高血糖素和线粒体解偶联剂羰基氰化物-3-氯苯腙都增加了丝氨酸同位素异构体，而鱼藤酮，复合物I的抑制剂，具有相反的作用。这些结果表明，13 C磁共振波谱监测2 - 13 C-甘氨酸诱导的大鼠离体肝细胞中丝氨酸同位素异构体的形成反映了线粒体氧化还原状态的变化。Magn Reson Med，2012年。© 2011 Wiley Periodicals，Inc.
The glycine cleavage system (GCS), the major pathway of glycine catabolism in liver, is found only in the mitochondria matrix and is regulated by the oxidized nicotinamide adenine dinucleotide (NAD+)/reduced nicotinamide adenine dinucleotide (NADH) ratio. In conjunction with serine hydroxymethyltransferase, glycine forms the 1 and 2 positions of serine, while the 3 position is formed exclusively by GCS. Therefore, we sought to exploit this pathway to show that quantitative measurements of serine isotopomers in liver can be used to monitor the NAD+/NADH ratio using13C NMR spectroscopy. Rat hepatocytes were treated with modulators of GCS activity followed by addition of 2‐13C‐glycine, and the changes in the proportions of newly synthesized serine isotopomers were compared to controls. Cysteamine, a competitive inhibitor of GCS, prevented formation of mitochondrial 3‐13C‐serine and 2,3‐13C‐serine isotopomers while reducing 2‐13C‐serine by 55%, demonstrating that ca. 20% of glycine‐derived serine is produced in the cytosol. Glucagon, which activates GCS activity, and the mitochondrial uncoupler carbonyl cyanide‐3‐chlorophenylhydrazone both increased serine isotopomers, whereas rotenone, an inhibitor of complex I, had the opposite effect. These results demonstrate that13C magnetic resonance spectroscopy monitoring of the formation of serine isotopomers in isolated rat hepatocytes given 2‐13C‐glycine reflects the changes of mitochondrial redox status. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.