Bio-pharmacological study for the action of bioactive molecules which control the reciprocal relationship between mast cells and other inflammatory cells

本论文主要研究了控制肥大细胞与其他炎症细胞相互作用的生物活性分子的作用机制的基本问题，主要集中在以下三个方面。1.肥大细胞合成组胺的研究。(1)从小鼠肥大细胞瘤P-815细胞中分离L-组氨酸脱羧酶，并测定其cDNA衍生的氨基酸序列。(2)从头合成的L-组氨酸脱羧酶及其mRNA的协同作用，发现在培养的肥大细胞与两种不同的兴奋剂处理;地塞米松和12-O-十四烷酰佛波醇13-乙酸酯，或二丁酰cAMP和钙离子载体A23187。(3)怀疑L-组氨酸脱羧酶可能存在翻译后加工。2.肥大细胞与内皮细胞及血小板相互作用之研究。(1)PGD_2是肥大细胞代谢产物DELTA^<12>-PGJ_2，抑制内皮细胞生长，但诱导内皮细胞产生31 kDa的血红素加氧酶蛋白。(2)内皮细胞PGI_2通过Gs-coupled腺苷酸环化酶刺激cAMP合成。(3)PGI_2受体对凝血酶或ATP诱导的肥大细胞瘤细胞内Ca_（2+）动员的差异调节(4)用不可逆特异性光亲和探针鉴定肥大细胞瘤细胞和血小板的PGI_2受体。3.前列腺素E受体亚型的结构与功能研究。以及它们在各种组织中的mRNA表达。(1)小鼠前列腺素E受体EP_3亚型和EP_2亚型cDNA的克隆与表达(2)通过选择性剪接获得了两种具有不同C端结构域的PGE受体EP_3亚型的功能性cDNA。两种形式决定了配体结合亲和力和激动剂诱导的脱敏敏感性。

We have investigated the basic problems about the action mechanisms of bioactive molecules which control the reciprocal relation between mast cells and other inflammatory cells, focused on following three points. 1. Studies on histamine synthesis in mast cells. (1) Isolation of L-histidine decarboxylase from mouse mastocytoma P-815 cells was performed, and is cDNA-derived amino acid sequence was determined. (2) Synergistic effects of de novo synthesis of L-histidine decarboxylase and its mRNA was found in cultured mast cells treated with two different stimulants; dexamethasone and 12-O-tetradecanoylphorbol 13-acetate, or dibutyryl cAMP and calcium ionophore A23187. (3) Possible post-translational processing of L-histidine decarboxylase was suspected. 2. Studies on cellular interaction between mast cells and endothelial cells or platelets. (1) PGD_2, is metabolite DELTA^<12>-PGJ_2, from mast cells inhibited cell growth of, but induced 31kDa protein, which was hemeoxygenase, in endothelial cells. (2) PGI_2 from endothelial cells stimulated cAMP synthesis via Gs-coupled adenylate cyclase. (3) Differential regulation of thrombin- or ATP-induced mobilization of intracellular Ca_<2+> by PGI_2 receptor in mastocytoma cells. (4) PGI_2 receptors in mastocytoma cells and platelets were identified by use of irreversible specific photoaffinity probe. 3. Studies on structure and function of prostaglandin E receptor subtypes. and on their mRNA expression in various tissues. (1) Cloning and expression of cDNAs for mouse prostaglandin E receptors, EP_3 subtype and EP_2 subtypes. (2) Functional cDNA for two isoforms of PGE receptor EP_3 subtype with different C-terminal domains which were derived from alternative splicing were obtained. Two forms determined ligand-binding affinity and sensitivity of agonist-induced desensitization.