Grossmann E M, Longo W E, Mazuski J E, Panesar N, Kaminski D L
Theodore Cooper Surgical Research Institute, Saint Louis University School of Medicine, St. Louis, MO 63110-0250, USA.
J Gastrointest Surg. 2000 Mar-Apr;4(2):193-200. doi: 10.1016/s1091-255x(00)80056-6.
Eicosanoids are involved in gallbladder inflammation, epithelial water transport, and mucous secretion. Phospholipase Asubscript2 enzymes liberate arachidonic acid from membrane phospholipids for the synthesis of eicosanoids. The purpose of this study was to determine the effect of selective cytoplasmic and secretory phospholipase A2 inhibitors on basal and stimulated arachidonic acid and prostaglandin E2 release in gallbladder cells. Western immunoblotting was employed to evaluate both cytosolic and secretory phospholipase A2 enzymes in human gallbladder cells. Cells were incubated for 22 hours with (3)H-labeled arachidonic acid. Arachidonic acid and prostaglandin E2 release was then measured in the supernate after 2 hours of exposure to human interleukin-1beta, alone or after pretreatment for 1 hour with the inhibitors. Unstimulated gallbladder cells express both 85 kDa cytosolic and 14 kDa secretory phospholipase A2++. The 85 kDa phospholipase A2 was induced by interleukin-1beta, whereas there was no apparent change in secretory phospholipase A2 enzyme concentrations. Both the secretory phospholipase A2 inhibitor p-bromophenylacyl bromide and the cytosolic phospholipase A2 inhibitor arachidonyl trifluoromethyl ketone decreased basal and interleukin-1beta-stimulated arachidonic acid release. In contrast, only inhibition of cytosolic phospholipase A2 led to a decrease in interleukin-1beta-stimulated prostaglandin E2 release. Basal and interleukin-1beta-stimulated arachidonic acid release appears to be the result of the activity of both cytosolic and secretory phospholipase A2. Interleukin-1beta-stimulated prostaglandin E2 release appears to be dependent on the activity of cytosolic phospholipase A2.
类二十烷酸参与胆囊炎症、上皮细胞水转运和黏液分泌。磷脂酶A2 可从膜磷脂中释放花生四烯酸用于合成类二十烷酸。本研究的目的是确定选择性胞质和分泌型磷脂酶A2抑制剂对胆囊细胞中基础和刺激状态下花生四烯酸及前列腺素E2释放的影响。采用蛋白质免疫印迹法评估人胆囊细胞中的胞质和分泌型磷脂酶A2 。细胞与³H标记的花生四烯酸孵育22小时。然后在单独暴露于人类白细胞介素-1β 2小时后或先用抑制剂预处理1小时后，测量上清液中花生四烯酸和前列腺素E2的释放量。未受刺激的胆囊细胞同时表达85 kDa的胞质磷脂酶A2和14 kDa的分泌型磷脂酶A2++ 。85 kDa的磷脂酶A2由白细胞介素-1β诱导，而分泌型磷脂酶A2的酶浓度没有明显变化。分泌型磷脂酶A2抑制剂对溴苯甲酰溴和胞质磷脂酶A2抑制剂花生四烯酰三氟甲基酮均降低基础和白细胞介素-1β刺激的花生四烯酸释放。相比之下，只有抑制胞质磷脂酶A2才会导致白细胞介素-1β刺激的前列腺素E2释放减少。基础和白细胞介素-1β刺激的花生四烯酸释放似乎是胞质和分泌型磷脂酶A2共同作用的结果。白细胞介素-1β刺激的前列腺素E2释放似乎依赖于胞质磷脂酶A2的活性。
