A study for drug-discovery based on physiological actions of prostanoid receptors

我们建立了每种类型前列腺素受体缺陷的小鼠，并通过检查每只敲除小鼠的表型来阐明前列腺素的生理作用：FP缺陷小鼠由于卵巢持续产生黄体酮而无法分娩，这表明PGF2α在正常分娩所需的黄体溶解中发挥作用。 IP缺陷小鼠表现出血栓形成倾向增加、炎症反应减少，并且没有表现出乙酸诱导的扭体反应，表明PG12参与促进炎症和痛觉。 EP3缺陷小鼠对内源性和外源性热原均未表现出发热反应； PGE2 通过 EP3 介导热原诱导的发热。 EP4缺陷小鼠在出生后三天内因动脉导管未通而死亡。 PGE2 通过 EP4 在新生儿动脉导管闭合中发挥重要作用。缺乏 EP2 的雌性小鼠由于排卵和受精受损而表现出生育能力下降； PGE2 … 更多通过 EP2 刺激卵丘扩张以及由此导致的 cAMP 水平增加，有助于排卵和受精。通过这些研究，我们证明了受体亚型特异性活性的重要性。此外，通过分析通过定点诱变方法产生的CHO细胞中表达的突变EP3受体，我们发现精氨酸残基（小鼠EP3受体中的Arg-306）的正电荷与配体中游离羧基残基的负电荷之间的离子相互作用对于Gs和Gq蛋白的激活至关重要，但这些残基中的氢相互作用足以激活Gs和Gq蛋白。 Gi蛋白的激活。基于这些发现，我们开发了四种 EP 受体亚型激动剂（EP1：ONO-DI-004、EP2：ONO-AE1-259、EP3：ONO-EA-248、EP4：ONO-AE1-329）和 EP1 特异性拮抗剂（ONO-8711），其受体特异性优异。这些化合物有潜力被开发为具有更特异治疗效果和更少副作用的强效药物。较少的

We established mice deficient in each type of prostanoid receptors, and clarified physiological roles of prostanoids by examining phenotypes in each knockout mice : FP-deficient mice fail to deliver their pups due to persistent production of progesterone in ovaries, indicating that PGF2α plays a role in luteolysis required for normal parturition. IP-deficient mice showed increased tendency of thrombosis, reduced responses of inflammation, and did not show acetic acid-induced writhing responses, indicating that PG12 participates in promotion of inflammation and pain sensation. EP3-deficent mice did not show febrile responses to both endogenous and exogenous pyrogen; PGE2 mediates pyrogen-induced fever generation via EP3. EP4-deficient mice died within three days after birth due to patency of ductus arteriosus. PGE2 plays an essential role in neonatal closure of ductus arteriosus via EP4. EP2-deficent female mice showed reduced fertility due to impaired ovulation and fertilization; PGE2 … More contributes to ovulation and fertilization through stimulation of cumulus expansion via EP2 and the resultant increase in cAMP level. Through these studies, we demonstrated importance of receptor subtype-specific activities.Furthermore, by the analysis of mutant EP3 receptor expressed in CHO cells generated by the method of site-directed mutagenesis, we found that ionic interaction between plus charge of arginine-residue (Arg-306 in mouse EP3 receptor) and minus charge of free carboxyl-residue in ligands is essential for the activation of Gs and Gq proteins, but hydrogen interaction in these residues is enough for the activation of Gi protein. Based on these findings, we developed four agonists for EP receptor subtype (EP1 : ONO-DI-004, EP2 : ONO-AE1-259, EP3 : ONO-EA-248, EP4 : ONO-AE1-329) and an EP1-specific antagonist (ONO-8711) which are excellent in their receptor-specificity. These compounds have potential to be developed as powerful drugs with more specific therapeutic effects and less side effects. Less