Soluble proteins produced by probiotic bacteria regulate intestinal epithelial cell survival and growth
Soluble proteins produced by probiotic bacteria regulate intestinal epithelial cell survival and growth
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DOI：
10.1053/j.gastro.2006.11.022
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发表时间：
2007-02-01
期刊：
影响因子：
29.4
通讯作者：
Polk, D. Brent
中科院分区：
文献类型：
--
作者：
Yan, Fang;Cao, Hanwei;Polk, D. Brent
背景与目的：炎症细胞因子水平升高和肠上皮细胞凋亡导致上皮完整性破坏是炎症性肠病的主要病理因素。鼠李糖乳杆菌GG （Lactobacillus rhamnosus GG， LGG）和从LGG肉汤培养上清（LGG-s）中提取的因子通过调节信号通路，防止细胞因子诱导的人和小鼠肠上皮细胞凋亡。在这里，我们纯化并表征了调节肠上皮细胞抗凋亡和增殖反应的2种分泌的LGG蛋白。方法：从LGG-s中纯化LGG蛋白，对其进行分析，并在LGG条件细胞培养基（CM）中制备相应蛋白的免疫缺失多克隆抗体。用纯化蛋白处理小鼠结肠上皮细胞和培养的结肠外植体，无论是否存在肿瘤坏死因子（TNF）。检测Akt活化、细胞增殖、组织损伤、细胞凋亡和caspase-3活化。结果：从LGG-s中纯化出2个新蛋白p75（75千道尔顿）和p40（40千道尔顿）。这些纯化蛋白制剂均能激活Akt，抑制细胞因子诱导的上皮细胞凋亡，促进人和小鼠结肠上皮细胞和培养的小鼠结肠外植体的细胞生长。p75和p40显著降低了tnf诱导的结肠上皮损伤。igg - cm中p75和p40的免疫缺失逆转了igg - cm对Akt的激活及其对细胞因子诱导的肠上皮细胞凋亡和损失的抑制作用。结论：p75和p40是首批被证实通过特定信号通路促进肠上皮稳态的益生菌蛋白。这些发现表明，益生菌成分可能有助于预防细胞因子介导的胃肠道疾病。
Backgground & Aims: Increased inflammatory cytokine levels and intestinal epithelial cell apoptosis leading to disruption of epithelial integrity are major pathologic factors in inflammatory bowel diseases. The probiotic bacterium Lactobacillus rhamnosus GG (LGG) and factors recovered from LGG broth culture supernatant (LGG-s) prevent cytokine-induced apoptosis in human and mouse intestinal epithelial cells by regulating signaling pathways. Here, we purify and characterize 2 secreted LGG proteins that regulate intestinal epithelial cell antiapoptotic and proliferation responses. Methods: LGG proteins were purified from LGG-s, analyzed, and used to generate polyclonal antibodies for immunodepletion of respective proteins from LGG-conditioned cell culture media (CM). Mouse colon epithelial cells and cultured colon explants were treated with purified proteins in the absence or presence of tumor necrosis factor (TNF). Akt activation, proliferation, tissue injury, apoptosis, and caspase-3 activation were determined. Results: We purified 2 novel proteins, p75 (75 kilodaltons) and p40 (40 kilodaltons), from LGG-s. Each of these purified protein preparations activated Akt, inhibited cytokine-induced epithelial cell apoptosis, and promoted cell growth in human and mouse colon epithelial cells and cultured mouse colon explants. TNF-induced colon epithelial damage was significantly reduced by p75 and p40. Immunodepletion of p75 and p40 from LGG-CM reversed LGG-CM activation of Akt and its inhibitory effects on cytokine-induced apoptosis and loss of intestinal epithelial cells. Conclusions: p75 and p40 are the first probiotic bacterial proteins demonstrated to promote intestinal epithelial homeostasis through specific signaling pathways. These findings suggest that probiotic bacterial components may be useful for preventing cytokine-mediated gastrointestinal diseases.