Lo C J, Cryer H G, Fu M, Lo F R
Department of Surgery, University of California, Los Angeles, USA.
J Trauma. 1998 Jul;45(1):19-23; discussion 23-4. doi: 10.1097/00005373-199807000-00004.
Prostaglandin E2 (PGE2) is a major contributor to the production and maintenance of immunosuppression after overwhelming injury, leading to increased infectious morbidity and mortality in trauma patients. Elucidation of the cellular pathways involved in PGE2 production could lead to potential therapeutic interventions. The purpose of this study was to determine the role of cyclooxygenase II (COX-2) in PGE2 production by Mphi and to investigate the cellular mechanism of COX-2 gene activation.
Mouse macrophages (Mphi), RAW 264.7, were exposed to Escherichia coli lipopolysaccharide (LPS) in the presence of cyclooxygenase inhibitors (ibuprofen or NS398). COX-1 and COX-2 mRNA expression and PGE2 production were measured by Northern blot assay and enzyme-linked immunosorbent assay, respectively. Nuclear factor kappaB (NFkappaB) activity was measured by electrophoretic mobility shift assay. To elucidate the role of NFkappaB in LPS-induced COX-2 gene activation, Mphi were exposed to LPS in the presence of an NFkappaB inhibitor, TPCK.
LPS increased Mphi COX-2 mRNA expression but had no effect on COX-1 mRNA expression. Both ibuprofen and NS398 inhibited COX-2 mRNA as well as PGE2 production by LPS-stimulated Mphi. In addition, LPS-induced NFkappaB activity was attenuated by these agents. Inhibition of NFkappaB with TPCK reduced COX-2 but not COX-1 gene expression and decreased PGE2 production by LPS-stimulated Mphi.
Our data indicate that COX-2 gene expression by LPS-stimulated Mphi is dependent on NFkappaB. Cyclooxygenase inhibitors reduced PGE2 production by inhibiting both COX-2 mRNA expression and preventing NFkappaB activation.
前列腺素E2（PGE2）是严重创伤后免疫抑制产生和维持的主要促成因素，导致创伤患者感染发病率和死亡率增加。阐明参与PGE2产生的细胞途径可能会带来潜在的治疗干预措施。本研究的目的是确定环氧化酶II（COX-2）在巨噬细胞产生PGE2中的作用，并研究COX-2基因激活的细胞机制。
将小鼠巨噬细胞（RAW 264.7）在环氧化酶抑制剂（布洛芬或NS398）存在的情况下暴露于大肠杆菌脂多糖（LPS）。分别通过Northern印迹分析和酶联免疫吸附测定法测量COX-1和COX-2 mRNA表达以及PGE2的产生。通过电泳迁移率变动分析测量核因子κB（NFκB）活性。为了阐明NFκB在LPS诱导的COX-2基因激活中的作用，将巨噬细胞在NFκB抑制剂TPCK存在的情况下暴露于LPS。
LPS增加了巨噬细胞COX-２mRNA表达，但对COX-1 mRNA表达没有影响。布洛芬和NS398均抑制LPS刺激的巨噬细胞的COX-2 mRNA以及PGE2的产生。此外，这些药物减弱了LPS诱导的NFκB活性。用TPCK抑制NFκB可降低LPS刺激的巨噬细胞的COX-2但不降低COX-1基因表达，并减少PGE2的产生。
我们的数据表明，LPS刺激的巨噬细胞的COX-2基因表达依赖于NFκB。环氧化酶抑制剂通过抑制COX-2 mRNA表达和阻止NFκB激活来减少PGE2的产生。
