Role of glycoproteins having affinity to GlcNAc-oligomer specific DSA lectin, Putative receptor coupled to histamine release including Gi protein pathway of mast cells.

大鼠腹膜肥大细胞有两个激活途径，一个是大鼠依赖的途径，另一个是大鼠不依赖的百日咳毒素敏感的g蛋白（Gi）途径。glcnac -寡聚物特异性凝集素Datura stramonium agglutin （DSA）是gi蛋白途径的大独立作用位点（假定的受体）的激动剂之一。DSA诱导它们的初始激活是细胞内钙浓度的短暂增加，随后细胞骨架的组装，共聚焦荧光显微镜分析方法显示化合物48/80（48/80）。DSA诱导的肥大细胞活化具有糖特异性，可被其他glcnac特异性凝集素（如WGA、STA和LEA）抑制，但不受ConA的抑制。拮抗剂凝集素与相应的糖蛋白结合，本身不激活gi -蛋白途径，但干扰糖蛋白与DSA的相互作用。碱性释放剂48/80、PE16和缓激肽均能促进DSA诱导的组胺释放，进一步表明它们具有相同的作用机制，均与含有glcnac残基的糖蛋白有关。Gi拮抗剂阳离子苯扎氯铵对DSA诱导的组胺释放具有可逆抑制作用，而阴离子聚合物haparin则无此作用。然而，48/80或PE16诱导的组胺释放被苯甲氯铵和阴离子聚合物（肝素、去n -硫酸肝素、聚天冬氨酸和聚谷氨酸）抑制。唾液酸也很重要，因为MAM（唾液酸特异性凝集素）和神经氨酸酶抑制DSA、48/80、PE16、P物质和缓激肽诱导的组胺释放。我们对大鼠腹膜肥大细胞的糖蛋白进行染色。凝集素印迹法检测到至少4种与DSA、WGA和MAM有亲和力且对神经氨酸酶处理敏感的糖蛋白。其中一些可能是假定的与组胺释放偶联的受体，包括gi蛋白途径。这些研究可能对开发治疗上有用的抑制剂和拮抗剂具有重要意义。少

Rat peritoneal mast cells have two activation pathway, an lgE-dependent pathway and an lgE-independent, pertussis toxin-sensitive G-protein (Gi) pathway. GlcNAc-oligomer specific lectin Datura stramonium agglutin (DSA) is one of the agonists of the lgE-independent action sites (putative recepotor) of the Gi-protein pathway. Their initial activation induced by DSA was a transient increase of intracellular calcium concentration followed by assembly of cytoskeleton as was compound 48/80 (48/80) by the method of confocal fluorescence microscopic analysis. Mast cell activation induced by DSA was sugar-specific and inhibited by other GlcNAc-specific lectins, such as WGA, STA and LEA, but not by ConA.Antagonist lectins bound to the corresponding glycoproteins and did not activate the Gi-protein pathway by themselves, but interfered with the interaction between the glycoproteins and DSA.The basic releasers 48/80, PE16 and bradykinin additively enhanced the histamine release induced by DSA, sug … More gesting that they share the same mechanisms of action, in which glycoproteins containing GlcNAc-residues were involved. Cationic benzalkonium chloride, an antagonist of Gi, irreversively inhibited the histamine release induced by DSA, but anionic polymer haparin did not. However, the histamine release induced by 48/80 or PE16 was inhibited by benzalkonium chloride and aniomic polymers (heparin, de-N-sulfated heparin, poly-aspartic acid, and poly-glutamic acid). Sialic acid was also important, since MAM (sialic acid-specific lectin) and neuraminidase inhibited the histamine release induced by DSA, 48/80, PE16, substance P and bradykinin. We stained the glycoproteins of rat peritoneal mast cells. At least four glycoproteins with affinity to DSA, WGA and MAM, and sensitive to neuraminidase-treatment were detected by lectin-blotting. Some of them may be putative receptors coupled to histamine release including the Gi-protein pathway. These studies may have important implications of the development of therapeutically useful inhibitors and antagonists. Less