Cornish Anthony S, Jijon Humberto, Yachimec Christine, Madsen Karen L
Division of Gastroenterology, University of Alberta, Edmonton, Canada.
Shock. 2002 Jul;18(1):93-6. doi: 10.1097/00024382-200207000-00017.
In the intestine, epithelial cells continually produce and secrete low levels of nitric oxide (NO). Salmonella sp. invade epithelium by responding to environmental stimuli. The aims of this study were to determine the effect of reactive nitrogen intermediates (RNIs) on S. dublin and S. typhimurium growth and invasion of T84 epithelial monolayers. Intracellular NO formation was inhibited by 7-nitroindazole (7-NI) or N(G)-monomethyl-L-arginine, monoacetate (L-NMMA); extracellular NO and peroxynitrite were scavenged with ferro-hemoglobin or urate. The effect of authentic peroxynitrite (ONOO-); 3-morpholino-sydnonimine (SIN-1), which releases ONOO- via NO and superoxide; spermine NONOate, which releases only NO; or superoxide generated by xanthine oxidase and pterin on S. dublin and S. typhimurium growth and invasion were examined. Inhibition of NO synthesis and scavenging of extracellular NO or peroxynitrite reduced S. dublin invasion into T84 monolayers and enhanced bacterial growth. Pre-exposure of S. dublin to ONOO- and SIN-1 increased subsequent bacterial invasion into T84 monolayers. Conversely, exposure of bacteria to spermine NONOate or superoxide did not affect S. dublin invasion. In contrast, S. typhimurium invasion was not affected by pre-treatment with NO donors. In conclusion, exposure of S. dublin to ONOO- enhances the ability of the bacteria to invade epithelial cells. These results suggest that luminal ONOO- may have a novel role as an extracellular signal between invasive bacteria and epithelial cells.
在肠道中，上皮细胞持续产生并分泌低水平的一氧化氮（NO）。沙门氏菌属通过对环境刺激作出反应来侵袭上皮细胞。本研究的目的是确定活性氮中间体（RNI）对都柏林沙门氏菌和鼠伤寒沙门氏菌生长以及对T84上皮单层细胞侵袭的影响。用7-硝基吲唑（7-NI）或N（G）-单甲基-L-精氨酸单乙酸盐（L-NMMA）抑制细胞内NO的形成；用铁血红蛋白或尿酸清除细胞外NO和过氧亚硝酸盐。检测了真实的过氧亚硝酸盐（ONOO-）、通过NO和超氧化物释放ONOO-的3-吗啉代-sydnonimine（SIN-1）、仅释放NO的精胺NONOate或黄嘌呤氧化酶和蝶呤产生的超氧化物对都柏林沙门氏菌和鼠伤寒沙门氏菌生长及侵袭的影响。抑制NO合成以及清除细胞外NO或过氧亚硝酸盐可减少都柏林沙门氏菌对T84单层细胞的侵袭并促进细菌生长。将都柏林沙门氏菌预先暴露于ONOO-和SIN-1可增加随后细菌对T84单层细胞的侵袭。相反，将细菌暴露于精胺NONOate或超氧化物并不影响都柏林沙门氏菌的侵袭。相比之下，用NO供体预处理对鼠伤寒沙门氏菌的侵袭没有影响。总之，将都柏林沙门氏菌暴露于ONOO-可增强细菌侵袭上皮细胞的能力。这些结果表明，管腔内的ONOO-可能作为侵袭性细菌与上皮细胞之间的一种新型细胞外信号发挥作用。
