Deniel Nicolas, Marion-Letellier Rachel, Charlionet Roland, Tron François, Leprince Jérôme, Vaudry Hubert, Ducrotté Philippe, Déchelotte Pierre, Thébault Sandrine
Groupe Aden EA3234, Université de Rouen, IFRMP23, 22 boulevard Gambetta, 76183 Rouen cedex 1, France.
Mol Cell Proteomics. 2007 Oct;6(10):1671-9. doi: 10.1074/mcp.M600428-MCP200. Epub 2007 Jun 2.
Glutamine plays a key role in the metabolism of rapidly dividing cells, including enterocytes and lymphocytes, which may contribute to its beneficial clinical effects. Gut mucosal homeostasis is achieved through a balance between cell proliferation and apoptosis. In T cells, glutamine up-regulates antiapoptotic proteins and down-regulates proapoptotic proteins. In gut mucosa, glutamine prevents apoptosis in rat epithelial cell lines, whereas glutamine starvation induces apoptosis through caspase activation. Finally glutamine specifically prevents tumor necrosis factor-alpha-related apoptosis in the human intestinal cell line HT-29. Comparative functional proteomics enables the characterization of each differentially expressed protein in intestinal cells in response to modifications of nutritional environment. The influence of glutamine on intestinal proteome expression in apoptotic conditions has not been studied and evaluated. This comparative proteomics study was performed in the human epithelial intestinal cell line HCT-8 under experimental apoptotic conditions to investigate the influence of glutamine on protein expression during apoptosis. The pharmaconutritional effects of glutamine were determined under 2 mm (physiological concentration) and 10 mm (pharmaconutritional concentration) conditions. About 1,800 protein spots were revealed in both conditions. Comparative assessments indicated that 28 proteins were differentially expressed significantly (i.e. at least 2-fold modulated and Student's t test with p </= 0.05) in response to an increase of glutamine concentration in the culture medium. Twenty-four proteins were identified by mass spectrometry and associated databases. From these proteins, 34% are involved in cell cycle and apoptosis mechanisms, 17% are involved in signal transduction, and 13% are involved in cytoskeleton organization. These data were integrated in a proposed schema of the interactome under apoptotic conditions. In conclusion, this study provides the first holistic picture of proteome modulation by glutamine in a human enterocytic cell line under apoptotic conditions and supports further evaluation of nutritional modulation of human intestinal proteome in various pathological conditions where apoptosis may be involved.
谷氨酰胺在快速分裂细胞（包括肠上皮细胞和淋巴细胞）的代谢中起关键作用，这可能是其产生有益临床效果的原因。肠道黏膜稳态是通过细胞增殖和凋亡之间的平衡来实现的。在T细胞中，谷氨酰胺上调抗凋亡蛋白并下调促凋亡蛋白。在肠道黏膜中，谷氨酰胺可防止大鼠上皮细胞系发生凋亡，而谷氨酰胺缺乏则通过半胱天冬酶激活诱导凋亡。最后，谷氨酰胺可特异性地防止人肠道细胞系HT - 29中与肿瘤坏死因子-α相关的凋亡。比较功能蛋白质组学能够对肠道细胞中每种因营养环境改变而差异表达的蛋白质进行表征。谷氨酰胺对凋亡条件下肠道蛋白质组表达的影响尚未得到研究和评估。本比较蛋白质组学研究在人上皮性肠细胞系HCT - 8的实验性凋亡条件下进行，以研究谷氨酰胺对凋亡过程中蛋白质表达的影响。在2 mM（生理浓度）和10 mM（药理营养浓度）条件下测定了谷氨酰胺的药理营养作用。在这两种条件下均检测到约1800个蛋白质斑点。比较评估表明，随着培养基中谷氨酰胺浓度的增加，有28种蛋白质差异表达显著（即至少2倍调节且Student t检验p≤0.05）。通过质谱和相关数据库鉴定出了24种蛋白质。在这些蛋白质中，34%参与细胞周期和凋亡机制，17%参与信号转导，13%参与细胞骨架组织。这些数据被整合到凋亡条件下相互作用组的拟议模式中。总之，本研究提供了在凋亡条件下谷氨酰胺对人肠细胞系蛋白质组调节的首张整体图谱，并支持在可能涉及凋亡的各种病理条件下进一步评估人肠道蛋白质组的营养调节作用。
