Cottrell Graeme S, Amadesi Silvia, Pikios Stella, Camerer Eric, Willardsen J Adam, Murphy Brett R, Caughey George H, Wolters Paul J, Coughlin Shaun R, Peterson Anders, Knecht Wolfgang, Pothoulakis Charalabos, Bunnett Nigel W, Grady Eileen F
Center for the Neurobiology of Digestive Disease, Department of Surgery, University of California, San Francisco, San Francisco, California 94143-0660, USA.
Gastroenterology. 2007 Jun;132(7):2422-37. doi: 10.1053/j.gastro.2007.03.101. Epub 2007 Apr 13.
BACKGROUND & AIMS: We studied the role of protease-activated receptor 2 (PAR(2)) and its activating enzymes, trypsins and tryptase, in Clostridium difficile toxin A (TxA)-induced enteritis.
We injected TxA into ileal loops in PAR(2) or dipeptidyl peptidase I (DPPI) knockout mice or in wild-type mice pretreated with tryptase inhibitors (FUT-175 or MPI-0442352) or soybean trypsin inhibitor. We examined the effect of TxA on expression and activity of PAR(2) and trypsin IV messenger RNA in the ileum and cultured colonocytes. We injected activating peptide (AP), trypsins, tryptase, and p23 in wild-type mice, some pretreated with the neurokinin 1 receptor antagonist SR140333.
TxA increased fluid secretion, myeloperoxidase activity in fluid and tissue, and histologic damage. PAR(2) deletion decreased TxA-induced ileitis, reduced luminal fluid secretion by 20%, decreased tissue and fluid myeloperoxidase by 50%, and diminished epithelial damage, edema, and neutrophil infiltration. DPPI deletion reduced secretion by 20% and fluid myeloperoxidase by 55%. In wild-type mice, FUT-175 or MPI-0442352 inhibited secretion by 24%-28% and tissue and fluid myeloperoxidase by 31%-71%. Soybean trypsin inhibitor reduced secretion to background levels and tissue myeloperoxidase by up to 50%. TxA increased expression of PAR(2) and trypsin IV in enterocytes and colonocytes and caused a 2-fold increase in Ca(2+) responses to PAR(2) AP. AP, tryptase, and trypsin isozymes (trypsin I/II, trypsin IV, p23) caused ileitis. SR140333 prevented AP-induced ileitis.
PAR(2) and its activators are proinflammatory in TxA-induced enteritis. TxA stimulates existing PAR(2) and up-regulates PAR(2) and activating proteases, and PAR(2) causes inflammation by neurogenic mechanisms.
我们研究了蛋白酶激活受体2（PAR(2)）及其激活酶胰蛋白酶和类胰蛋白酶在艰难梭菌毒素A（TxA）诱导的肠炎中的作用。
我们将TxA注入PAR(2)或二肽基肽酶I（DPPI）基因敲除小鼠的回肠肠袢，或注入用类胰蛋白酶抑制剂（FUT-175或MPI-0442352）或大豆胰蛋白酶抑制剂预处理的野生型小鼠的回肠肠袢。我们检测了TxA对回肠和培养的结肠上皮细胞中PAR(2)和胰蛋白酶IV信使核糖核酸表达及活性的影响。我们给一些用神经激肽1受体拮抗剂SR140333预处理的野生型小鼠注射激活肽（AP）、胰蛋白酶、类胰蛋白酶和p23。
TxA增加了液体分泌、液体和组织中的髓过氧化物酶活性以及组织学损伤。PAR(2)基因缺失减轻了TxA诱导的回肠炎，使肠腔液体分泌减少20%，组织和液体中的髓过氧化物酶减少50%，并减轻了上皮损伤、水肿和中性粒细胞浸润。DPPI基因缺失使分泌减少20%，液体中的髓过氧化物酶减少55%。在野生型小鼠中，FUT-175或MPI-0442352使分泌减少24% - 28%，组织和液体中的髓过氧化物酶减少31% - 71%。大豆胰蛋白酶抑制剂将分泌减少到背景水平，组织中的髓过氧化物酶减少多达50%。TxA增加了肠上皮细胞和结肠上皮细胞中PAR(2)和胰蛋白酶IV的表达，并使对PAR(2)激活肽的Ca(2+)反应增加了2倍。激活肽、类胰蛋白酶和胰蛋白酶同工酶（胰蛋白酶I/II、胰蛋白酶IV、p23）导致回肠炎。SR140333预防了激活肽诱导的回肠炎。
PAR(2)及其激活剂在TxA诱导的肠炎中具有促炎作用。TxA刺激现有的PAR(2)并上调PAR(2)和激活蛋白酶，且PAR(2)通过神经源性机制引发炎症。
