Cortese J F, Spannhake E W, Eisinger W, Potter J J, Yang V W
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Prostaglandins. 1995 Mar;49(3):155-66. doi: 10.1016/0090-6980(95)00003-s.
Leukotrienes (LTs), the 5-lipoxygenase (5-LOX) metabolites of arachidonic acid, have roles in many biological processes relevant to the gastrointestinal tract, including intestinal inflammation. We screened two well-known human intestinal epithelial cell lines, HT29 and Caco-2, for evidence of LT-associated enzyme transcripts and LT synthesis. Northern blot analysis of total RNA from both intestinal lines demonstrated high levels of transcripts for LTA4 hydrolase, a multisubstrate enzyme that converts the 5-LOX metabolite, LTA4, to LTB4. With total RNA, the 5-LOX transcript was detected only in HT29. Caco-2 failed to show 5-LOX message even with poly A-containing RNA, although the transcript could be amplified with the polymerase chain reaction. Messenger RNA for FLAP, the 5-lipoxygenase-activating protein, was detectable in both cell lines, but only with poly A-containing RNA. In a sonicated cell preparation, HT29, but not Caco-2, revealed detectable levels of 5-HETE and LTB4. These results suggest that certain intestinal epithelial cells possess a limited capacity to synthesize LTs.
白三烯（LTs）是花生四烯酸的5-脂氧合酶（5-LOX）代谢产物，在许多与胃肠道相关的生物过程中发挥作用，包括肠道炎症。我们筛选了两种著名的人肠上皮细胞系HT29和Caco-2，以寻找LT相关酶转录本和LT合成的证据。对这两种肠道细胞系的总RNA进行Northern印迹分析，结果显示LTA4水解酶的转录本水平很高，LTA4水解酶是一种多底物酶，可将5-LOX代谢产物LTA4转化为LTB4。在总RNA中，仅在HT29中检测到5-LOX转录本。即使使用含poly A的RNA，Caco-2也未显示出5-LOX信息，尽管该转录本可以通过聚合酶链反应进行扩增。在两种细胞系中均检测到5-脂氧合酶激活蛋白FLAP的信使RNA，但仅在含poly A的RNA中检测到。在超声处理的细胞制剂中，HT29而非Caco-2显示出可检测水平的5-羟基二十碳四烯酸（5-HETE）和LTB4。这些结果表明某些肠上皮细胞合成LTs的能力有限。
