Xia Harry Hua-Xiang, Lam Shiu Kum, Chan Annie O O, Lin Marie Chia Mi, Kung Hsiang Fu, Ogura Keiji, Berg Douglas E, Wong Benjamin Chun-Yu
Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
World J Gastroenterol. 2005 Apr 7;11(13):1946-50. doi: 10.3748/wjg.v11.i13.1946.
Helicobacter pylori (H pylori) is associated with increased gastric inflammatory and epithelial expression of macrophage migration inhibitory factor (MIF) and gastric epithelial cell proliferation. This study aimed at determining whether H pylori directly stimulates release of MIF in monocytes, whether the cag pathogenicity island (PAI) is involved for this function, and whether MIF stimulated by H pylori increases gastric epithelial cell proliferation in vitro.
A cytotoxic wild-type H pylori strain (TN2), its three isogenic mutants (TN2Deltacag, TN2DeltacagA and TN2DeltacagE) were co-cultured with cells of a human monocyte cell line, THP-1, for 24 h at different organism/cell ratios. MIF in the supernatants was measured by an ELISA. Cells of a human gastric cancer cell line, MKN45, were then co-cultured with the supernatants, with and without monoclonal anti-MIF antibody for 24 h. The cells were further incubated for 12 h after addition of 3H-thymidine, and the levels of incorporation of 3H-thymidine were measured with a liquid scintillation counter.
The wild-type strain and the isogenic mutants, TN2DeltacagA and TN2 DeltacagE, increased MIF release at organism/cell ratios of 200/1 and 400/1, but not at the ratios of 50/1 and 100/1. However, the mutant TN2delta cag did not increase the release of MIF at any of the four ratios. 3H-thymidine readings for MKN-45 cells were significantly increased with supernatants derived from the wild-type strain and the mutants TN2DeltacagA and TN2DeltacagE, but not from the mutant TN2Deltacag. Moreover, in the presence of monoclonal anti-MIF antibody, the stimulatory effects of the wild-type strain on cell proliferation disappeared.
H pylori stimulates MIF release in monocytes, likely through its cag PAI, but not related to cagA or cagE. H pylori-stimulated monocyte culture supernatant increases gastric cell proliferation, which is blocked by anti-MIF antibody, suggesting that MIF plays an important role in H pylori-induced gastric epithelial cell proliferation.
幽门螺杆菌（H pylori）与胃炎症增加、巨噬细胞移动抑制因子（MIF）的上皮表达以及胃上皮细胞增殖有关。本研究旨在确定幽门螺杆菌是否直接刺激单核细胞释放MIF，空泡毒素相关基因（cag）致病岛（PAI）是否参与此功能，以及幽门螺杆菌刺激产生的MIF是否在体外增加胃上皮细胞增殖。
将一株具有细胞毒性的野生型幽门螺杆菌菌株（TN2）及其三个同基因突变体（TN2Deltacag、TN2DeltacagA和TN2DeltacagE）与人单核细胞系THP-1的细胞以不同的菌/细胞比例共培养24小时。通过酶联免疫吸附测定法（ELISA）检测上清液中的MIF。然后将人胃癌细胞系MKN45的细胞与含有和不含有单克隆抗MIF抗体的上清液共培养24小时。加入3H-胸腺嘧啶核苷后，细胞再孵育12小时，并用液体闪烁计数器测量3H-胸腺嘧啶核苷的掺入水平。
野生型菌株以及同基因突变体TN2DeltacagA和TN2DeltacagE在菌/细胞比例为200/1和400/1时可增加MIF释放，但在50/1和100/1比例时则不然。然而，突变体TN2delta cag在这四个比例中的任何一个下均未增加MIF释放。来自野生型菌株以及突变体TN2DeltacagA和TN2DeltacagE的上清液使MKN-45细胞的3H-胸腺嘧啶核苷读数显著增加，但来自突变体TN2Deltacag的上清液则不然。此外，在存在单克隆抗MIF抗体的情况下，野生型菌株对细胞增殖的刺激作用消失。
幽门螺杆菌可能通过其cag PAI刺激单核细胞释放MIF，但与cagA或cagE无关。幽门螺杆菌刺激的单核细胞培养上清液可增加胃细胞增殖，而抗MIF抗体可阻断这种增殖，这表明MIF在幽门螺杆菌诱导的胃上皮细胞增殖中起重要作用。
