Differential Regulation of Protein Synthesis and mTOR Signaling in Skeletal Muscle and Visceral Tissues of Neonatal Pigs After a Meal
Differential Regulation of Protein Synthesis and mTOR Signaling in Skeletal Muscle and Visceral Tissues of Neonatal Pigs After a Meal
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DOI：
10.1203/pdr.0b013e3182276cfa
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发表时间：
2011-09-01
影响因子：
3.6
通讯作者：
Davis, Teresa A.
中科院分区：
文献类型：
--
作者：
Gazzaneo, Maria C.;Orellana, Renan A.;Davis, Teresa A.
新生儿餐后蛋白质合成（PS）增加，但餐后不同组织中PS变化的时间过程尚不清楚。我们的目的是评估新生猪（n = 6/组; 5至7日龄）餐后4小时内组织PS、哺乳动物雷帕霉素复合物靶蛋白1（mTORC 1）活化和多核糖体中核糖体蛋白（rp）mRNA比例的变化。结果表明，与混合纤维型肌肉相比，糖酵解型肌肉中PS的持续增加更持久，而氧化型肌肉没有变化。PS在肝脏、空肠和胰腺中增加，但在肾脏和心脏中不增加。喂食不影响AMP活化蛋白激酶或RAS相关GTP结合B活化。结节性硬化症复合体2磷酸化，富含脯氨酸的Akt底物的40 kD，mTOR，真核起始因子4 E结合蛋白，和rp S6激酶1在所有组织喂养后增加。rp S4和S8的mRNA编码的肝多聚核糖体的比例增加30分钟内喂养。这些结果表明，喂养刺激mTORC 1信号在肌肉和内脏，但mTORC 1激活单独是不足以刺激PS在所有组织。（儿科研究70：253-260，2011）
Protein synthesis (PS) increases after a meal in neonates, but the time course of the changes in PS in different tissues after a meal is unknown. We aimed to evaluate the changes in tissue PS, mammalian target of rapamycin complex 1 (mTORC1) activation, and proportion of ribosomal protein (rp) mRNAs in polysomes over 4 h after a bolus meal in neonatal pigs (n = 6/group; 5- to 7-d-old). The results show a more sustained increase in PS in glycolytic compared with mixed fiber type muscles and no changes in oxidative muscles. PS increased in liver, jejunum, and pancreas but not in kidney and heart. Feeding did not affect AMP-activated protein kinase or RAS-related GTP binding B activation. Phosphorylation of tuberous sclerosis complex 2, proline-rich Akt substrate of 40 kD, mTOR, eukaryotic initiation factor 4E binding protein, and rp S6 kinase 1 increased in all tissues after feeding. The proportion of mRNAs encoding rp S4 and S8 in liver polysomes increased within 30 min postfeeding. These results suggest that feeding stimulates mTORC1 signaling in muscle and viscera, but mTORC1 activation alone is not sufficient to stimulate PS in all tissues. (Pediatr Res 70: 253-260, 2011)