Molecular basis of prostanoid receptor-mediated pathogenesis and its drug application

(1)通过每种受体缺乏小鼠阐明前列腺素的病理生理作用：我们发现EP2缺乏在apc KO小鼠中减少了肠息肉的形成数量和大小。我们还发现野生型小鼠肠息肉中COX-2、EP2和VEGF表达加快，而EP2和Ape双敲除小鼠肠息肉中COX-2和VEGF表达微弱，提示COX-2和EP2之间存在正反馈调节。我们将dextransulfate （DSS）诱导的结肠炎模型引入ep缺陷小鼠。结果，只有ep4缺陷小鼠在3%DSS处理后出现严重结肠炎，而野生型小鼠没有明显的结肠炎。EP4已被证明能促进上皮细胞再生并抑制白细胞和淋巴细胞的活化。(2)前列腺素受体EP3发挥的信号转导新途径：EP3已被证明与Gi活性偶联，抑制腺苷酸周期和更多lase。EP3有多种异构体，它们的c端结构和激动剂依赖性Gi活性不同。我们发现，在COS-7细胞中表达的EP3受体以激动剂依赖的方式增强了其他受体刺激的Gs活性。EP3受体对Gs的超激活不受百日咳毒素处理的影响，表明这种超激活不是由gi介导的。无论EP3受体的c端结构如何，在任何类型的小鼠EP3受体亚型中都观察到Gs依赖于EP3激动剂的超激活。这种EP3信号可能反映了PGE2生理功能的某些方面，如痛觉。(3) EP4受体特异性配体的开发：研究了通过在PGE1 α链中引入杂原子来提高EP4受体的选择性和激动剂活性。在所合成的化合物中，16-苯基-omega-四烷-3,7-二硫apge1具有中等的ep4受体选择性和激动剂活性，被确定为新的化学先导物，可以通过修饰芳香部分进行进一步优化。在此基础上，我们还成功地合成了具有高选择性的ep4特异性拮抗剂。少

Results obtained by Kyoto University Group(1) Elucidation of patho-physiological roles of prostanoids by using each receptor-deficient mice :We found that EP2 deficiency attenuated intestinal polyp formation both in number and size in-Apc KO mice. We also showed acceleration of COX-2, EP2 and VEGF expression in the intestinal polyps of wild-type mice, but faint expression of COX-2 or VEGF in those of EP2 and Ape double-knockout mice, suggesting that there exists positive feedback regulation between COX-2 and EP2. We introduced dextransulfate (DSS)-induced colitis model into EP-deficient mice. As a result, only EP4-deficient mice showed severe colitis upon 3%DSS treatment that did not induce significant colitisin wild-type mice. EP4 has been shown to promote epithelial regeneration and to inhibit activation of leukocytes and lymphocytes.(2) The new signal transduction pathway exerted by prostanoid receptor EP3 :EP3 has been shown to be coupled to Gi activity, inhibition of adenylate cyc … More lase. EP3 has multiple isoforms that are different in their C-terminal structure and in their agonist-dependent Gi activity. We found that EP3 receptors expressed in COS-7 cells showed augmentation of other receptor-stimulated Gs activity in an agonist-dependent manner. The superactivation of Gs by EP3 receptors was not affected by the treatment of pertussis toxin, suggesting that the superactivation is not Gi-mediated. The EP3 agonist-dependent supeactivation of Gs is observed in any type of mouse EP3 receptor isoforms, irrespective of C-termnal structure of EP3 receptor. This EP3 signaling may reflect some aspects of the physiological function of PGE2, such as pain sensation.]Results obtained by Ono Pharmaceutical Co. Group(3) Development of EP4 receptor-specific ligands :Improvement of EP4-receptor selectivity and the agonist activity by introduction of heteroatoms into the alpha chain of PGE1 was investigated. Of the compounds produced, 16-phenyl-omega-tetranor-3,7-dithiaPGE1 possessing moderate EP4-receptor selectivity and agonist activity, was identified as a new chemical lead for further optimization by modification of the aromatic moiety Based on the information, we also successfully generated an EP4-specific antagonist with a high selectivity. Less