Antagonism of Protease-Activated Receptor 2 Protects against Experimental Colitis
Antagonism of Protease-Activated Receptor 2 Protects against Experimental Colitis
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DOI：
10.1124/jpet.111.187062
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发表时间：
2012-02-01
影响因子：
3.5
通讯作者：
Fairlie, David P.
中科院分区：
文献类型：
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作者：
Lohman, Rink-Jan;Cotterell, Adam J.;Fairlie, David P.
许多胰蛋白酶样丝氨酸蛋白酶如β-类胰蛋白酶参与结肠炎和炎性肠病的发病机制。个别蛋白酶的抑制剂在治疗此类病症中显示出有限的功效，但也可能破坏蛋白酶的消化和防御功能。在这里，我们研究是否掩盖他们的共同目标，蛋白酶激活受体2（PAR 2），是一种有效的治疗策略，用于治疗急性和慢性实验性结肠炎大鼠。在Wistar大鼠的急性（PAR 2激动剂诱导的）与慢性[2，4，6-三硝基苯磺酸（TNBS）诱导的]结肠炎模型中，评价了新型PAR 2拮抗剂（5-异恶唑酰基-Cha-Ile-螺[茚-1，4 '-哌啶]; GB 88）对结肠细胞中细胞内钙释放的阻断和抗炎活性。测量疾病进展（疾病活动指数、体重减轻和死亡率）和死后结肠组织病理学（炎症、肠壁厚度和髓过氧化物酶）。PAR 2和类胰蛋白酶共定位采用免疫组织化学方法进行研究。GB 88是比另一种已报道的化合物N-1-3-甲基丁酰-N-4-6-氨基己酰-哌嗪（ENMD-1068）更有效的结肠细胞PAR 2激活拮抗剂（IC 50 8 μ M vs 5 mM）。口服GB 88（10 mg/kg）可抑制PAR 2激动剂SLIGRL-NH 2诱导的大鼠急性结肠炎症，并显著降低水肿、粘蛋白耗竭、PAR 2受体内化和肥大细胞增多症。大鼠中慢性TNBS诱导的结肠炎通过GB 88（10 mg/kg/天p.o.）改善，其比临床使用的药物柳氮磺胺吡啶（100 mg/kg/天p.o.）更有效地降低死亡率和病理学（包括结肠阻塞、溃疡、壁厚度和髓过氧化物酶释放）。PAR 2拮抗剂在急性和慢性实验性结肠炎中的这些疾病改善性质强烈支持PAR 2和PAR 2活化蛋白酶的致病作用以及PAR 2拮抗剂在结肠炎性疾病中的治疗潜力。
Many trypsin-like serine proteases such as beta-tryptase are involved in the pathogenesis of colitis and inflammatory bowel diseases. Inhibitors of individual proteases show limited efficacy in treating such conditions, but also probably disrupt digestive and defensive functions of proteases. Here, we investigate whether masking their common target, protease-activated receptor 2 (PAR2), is an effective therapeutic strategy for treating acute and chronic experimental colitis in rats. A novel PAR2 antagonist (5-isoxazoyl-Cha-Ile-spiro[indene-1,4'-piperidine]; GB88) was evaluated for the blockade of intracellular calcium release in colonocytes and anti-inflammatory activity in acute (PAR2 agonist-induced) versus chronic [2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced] models of colitis in Wistar rats. Disease progression (disease activity index, weight loss, and mortality) and postmortem colonic histopathology (inflammation, bowel wall thickness, and myeloperoxidase) were measured. PAR2 and tryptase colocalization were investigated by using immunohistochemistry. GB88 was a more potent antagonist of PAR2 activation in colonocytes than another reported compound, N-1-3-methylbutyryl-N-4-6-aminohexanoyl-piperazine (ENMD-1068) (IC50 8 mu M versus 5 mM). Acute colonic inflammation induced in rats by the PAR2 agonist SLIGRL-NH2 was inhibited by oral administration of GB88 (10 mg/kg) with markedly reduced edema, mucin depletion, PAR2 receptor internalization, and mastocytosis. Chronic TNBS-induced colitis in rats was ameliorated by GB88 (10 mg/kg/day p.o.), which reduced mortality and pathology (including colon obstruction, ulceration, wall thickness, and myeloperoxidase release) more effectively than the clinically used drug sulfasalazine (100 mg/kg/day p.o.). These disease-modifying properties for the PAR2 antagonist in both acute and chronic experimental colitis strongly support a pathogenic role for PAR2 and PAR2-activating proteases and therapeutic potential for PAR2 antagonism in inflammatory diseases of the colon.