Mast cell tryptase regulates rat colonic myocytes through proteinase-activated receptor
Mast cell tryptase regulates rat colonic myocytes through proteinase-activated receptor
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DOI：
10.1172/jci119658
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发表时间：
1997-09-15
影响因子：
15.9
通讯作者：
Bunnett, NW
中科院分区：
文献类型：
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作者：
Corvera, CU;Dery, O;Bunnett, NW
蛋白酶活化受体-2 （PAR-2）是一种G蛋白偶联受体，可被胰蛋白酶样酶裂解和激活。PAR-2在小肠肠细胞中高度表达，在小肠肠细胞中被肠道胰蛋白酶激活。然而，PAR-2在结肠中的位置、激活机制和生物学功能尚不清楚。我们用免疫荧光法将PAR-2定位到大鼠结肠外肌层。通过免疫荧光和RT-PCR检测，原代培养的肌细胞也表达PAR-2。胰蛋白酶、SLIGRL-NH2（对应于PAR-2拴系配体）、肥大细胞胰蛋白酶和脱颗粒肥大细胞滤液刺激肌细胞中[Ca2+](i)的迅速增加。胰蛋白酶抑制剂BABIM可抑制对胰蛋白酶和肥大细胞滤液的反应，胰蛋白酶可使PAR-2脱敏。PAR-2的激活抑制了大鼠结肠条带的节律性收缩幅度。这种反应不受吲哚美辛、l -n - g -硝基精氨酸甲酯、缓激肽B-2受体拮抗剂和河豚毒素的影响。因此，PAR-2在结肠肌细胞中高度表达，在那里它可能被肥大细胞胰蛋白酶裂解和激活。这可能导致肥大细胞脱颗粒时结肠运动障碍。
Proteinase-activated receptor-2 (PAR-2) is a G protein-coupled receptor that is cleaved and activated by trypsin-like enzymes. PAR-2 is highly expressed by small intestinal enterocytes where it is activated by luminal trypsin. The location, mechanism of activation, and biological functions of PAR-2 in the colon, however, are unknown. We localized PAR-2 to the muscularis externa of the rat colon by immunofluorescence. Myocytes in primary culture also expressed PAR-2, assessed by immunofluorescence and RT-PCR. Trypsin, SLIGRL-NH2 (corresponding to the PAR-2 tethered ligand), mast cell tryptase, and a filtrate of degranulated mast cells stimulated a prompt increase in [Ca2+](i) in myocytes. The response to tryptase and the mast cell filtrate was inhibited by the tryptase inhibitor BABIM, and abolished by desensitization of PAR-2 with trypsin. PAR-2 activation inhibited the amplitude of rhythmic contractions of strips of rat colon. This response was unaffected by indomethacin, L-N-G-nitroarginine methyl ester, a bradykinin B-2 receptor antagonist and tetrodotoxin. Thus, PAR-2 is highly expressed by colonic myocytes where it may be cleaved and activated by mast cell tryptase. This may contribute to motility disturbances of the colon during conditions associated with mast cell degranulation.