Multifunction of mast cells in inflammation tissue

本研究旨在探讨肥大细胞在炎症组织中与其他细胞结合或不结合时的多种功能控制肥大细胞释放和合成组胺的功能。(1)组胺释放活性；合成了化合物48/80的活性三聚体Ca^<2+>依赖性组胺释放剂。三聚体的结合诱导花生四烯酸迅速积聚到PA、PI和PC中，同时在可检测的组胺释放之前，花生四烯酸从PE中减少。(2)组胺合成活性；肥大细胞中的组氨酸脱羧酶首先被纯化到电泳均匀性，其在SDS-PAGE上具有两个相同的亚基，Mr=31 kDa。糖皮质激素与活化的蛋白激酶c一起刺激肥大细胞瘤细胞中酶的重新合成。PGD_2与肥大细胞膜的结合可能通过受体本身的磷酸化-去磷酸化来控制。肥大细胞与其他细胞的相互作用。(1)肥大细胞到内皮细胞；肥大细胞PGD_2/ PGJ_2诱导内皮细胞重新合成一种新的31 kDa蛋白。(2)肥大细胞PGD_2增强了中性粒细胞对内皮细胞的粘附反应，其作用强于LTB_4。(3)经TPA处理后，预分化肥大细胞能够粘附活化的内皮细胞，通过蛋白激酶C的作用刺激未知蛋白的合成。

This research project was intended to investigate the multifunction of mast cells in conjunction with or without other cells in inflammation tissues.1 Control of mast cell function in release and synthesis of histamine. (1) Histamine releasing activity; active tridecamer of compound 48/80, a Ca^<2+>-dependent histamine releaser, was synthesized. The binding of tridecamer induced a rapid accumulation of the arachidonic acid into PA, PI and PC, with concomitant decrease of arachidonic acid from PE prior to the detectable histamine release. (2) Histamine synthesizing activity; histidine decarboxylase in mast cells has first been purified to electrophoretic homogeneity, which has two identical subunits having Mr=31 kDa on SDS-PAGE. The de novo synthesis of the enzyme in mastocytoma cells was stimulated by glucocorticoid in conjunction with activated protein kinase C. (3) Prostaglandin (PG) activity; PGD_2 binding to mast cell membrane is possibly controlled through phosphorylation-dephosphorylation of the receptor itself.2. Interaction of mast cell to other cells. (1) Mast cells to endothelial cells; PGD_2/ PGJ_2 from mast cells induced a de novo synthesis of a new 31 kDa protein in endothelial celts. (2) PGD_2 from mast cells enhanced reaction of neutrophil adhesion to endothelial cells, which activity is more potent than that of LTB_4. (3) Predifferentiated mast cells are capable of adhering to activated endothelial cells by TPA treatment, which stimulates unidentified protein synthesis by the action of protein kinase C.