Smith-Swintosky V L, Cheo-Isaacs C T, D'Andrea M R, Santulli R J, Darrow A L, Andrade-Gordon P
R. W. Johnson Pharmaceutical Research Institute, Spring House, Pennsylvania 19477-0776, U.S.A.
J Neurochem. 1997 Nov;69(5):1890-6. doi: 10.1046/j.1471-4159.1997.69051890.x.
Protease-activated receptor-2 (PAR-2) is a seven-transmembrane G protein-coupled receptor that possesses a structure and activation mechanism similar to those of the thrombin receptor. It is activated by low concentrations of trypsin (300 pM) and a synthetic hexapeptide [sequence of serine, leucine, isoleucine, glycine, arginine, leucine (SLIGRL), the rodent PAR-2 "tethered ligand"] representing the first six amino acids following the putative PAR-2 cleavage site. Previous studies have indicated that alpha-thrombin and SFLLRN (synthetic hexapeptide sequence of serine, phenylalanine, leucine, leucine, arginine, asparagine; the human thrombin receptor "tethered ligand") induce neurite retraction and neurotoxicity. Because of the strong similarities between thrombin receptor and PAR-2, we have proposed that PAR-2 may also participate in neurodegeneration. In the present study, we used reverse transcriptase polymerase chain reaction and immunocytochemistry to provide the first evidence that PAR-2 is present in the rat hippocampus. Moreover, we found SLIGRL to be toxic to hippocampal neurons in a concentration-dependent manner (> or = 100 microM). Calcium signaling studies were performed to aid in determining the mechanism by which PAR-2 activation is neurotoxic.
蛋白酶激活受体-2（PAR-2）是一种七跨膜G蛋白偶联受体，其结构和激活机制与凝血酶受体相似。它可被低浓度的胰蛋白酶（300 pM）和一种合成六肽[丝氨酸、亮氨酸、异亮氨酸、甘氨酸、精氨酸、亮氨酸（SLIGRL）序列，即啮齿动物PAR-2的“拴系配体”]激活，该六肽代表假定的PAR-2裂解位点后的前六个氨基酸。先前的研究表明，α-凝血酶和SFLLRN（丝氨酸、苯丙氨酸、亮氨酸、亮氨酸、精氨酸、天冬酰胺的合成六肽序列；人类凝血酶受体的“拴系配体”）可诱导神经突回缩和神经毒性。由于凝血酶受体与PAR-2之间存在很强的相似性，我们推测PAR-2可能也参与神经退行性变。在本研究中，我们使用逆转录聚合酶链反应和免疫细胞化学方法首次证明PAR-2存在于大鼠海马体中。此外，我们发现SLIGRL对海马神经元具有浓度依赖性毒性（≥100 μM）。进行了钙信号研究以帮助确定PAR-2激活产生神经毒性的机制。
