INTESTINAL GOBLET CELL FUNCTION

肠杯状细胞功能

• 批准号: 3232121
• 负责人: ROBERT D SPECIAN
• 金额: $ 10.75万
• 依托单位: LOUISIANA STATE UNIV HSC SHREVEPORT
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-04-01 至 1997-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3232121
• 关键词: antiinfective agents; cytotoxicity; enzyme activity; enzyme mechanism; gastrointestinal absorption /transport; gastrointestinal epithelium; gel; immunocytochemistry; immunotherapy; intestinal mucosa; ischemia; laboratory rabbit; laboratory rat; monoclonal antibody; mucins; orphan disease /drug; oxidative stress; peroxidases; reperfusion; secretion; superoxides; xanthine oxidase

The intestinal mucosa serves to absorb nutrients, solutes and fluid, but simultaneously exclude luminal macromolecules and bacteria. The mucosal barrier is composed of epithelial cells and their tight junctions; failure of the mucosal barrier can lead to the dissemination of bacteria and ultimately, multiple organ failure syndrome. Also protecting the epithelium, is the mucus gel, composed of mucins, cellular debris, and adherent IgA. Maintenance of the mucus gel is accomplished by the baseline secretion of mucins from goblet cells. Numerous pathophysiologic conditions, including cystic fibrosis and ulcerative colitis, demonstrate altered mucin production/secretion; no physiologic significance,, however, has been assigned to these phenomena. We propose to characterize the role of mucins and an oxidant-generating enzyme of goblet cell origin, intestinal peroxidase (IPO), in the pathogenesis of ischemia/reperfusion (I/R), using the total occlusion of the superior mesenteric artery as our model. First, we will determine the role of luminal xanthine oxidase and IPO, as well as their oxidants, superoxide anion radical and hypohalous acid, in the progression of mucosal injury, using isotopic and morphological end-points. Second, we will characterize the response of goblet cells to I/R-induced mucosal injury, especially, the secretion of mucins and mucin species, as well as the secretion of IPO. We will also determine the ability of mucins to scavenge IPO-generated hypohalous acids to protect the epithelium. Third, we will characterize the chemistry and physiology of IPO, including: isolation and chemical composition; kinetic, bactericidal and cytotoxic analysis; and the binding affinity of IPO to a reconstituted mucin gel in vitro. Finally, we will use the information gained from the characterization of mucins and IPO to attempt to interrupt the pathogenesis of I/R-induced mucosal injury in vivo. Using the occlusion of the SMA as a model, we will attempt to ameliorate mucosal damage by inactivation of IPO activity with anti-IPO antibodies. We will also attempt to scavenge reactive oxygen species in vivo with mucins. Finally, we will attempt to mimic I/R -induced mucosal injury With exogenous IPO and substrate. We hypothesize that the mucus gel is far more versatile and bioactive than previously thought. That under normal conditions, mucin-IPO interactions result in an antimicrobial-barrier in the intestine, but that under conditions of ischemia/reperfusion, this defense system results in the initiation of I/R-induced mucosal damage.

肠粘膜用于吸收营养物质、溶质和液体，但 同时排除管腔大分子和细菌。 粘膜 屏障由上皮细胞及其紧密连接组成; 粘膜屏障的失效可导致细菌的传播 最终导致多器官衰竭综合征 还保护 上皮是粘液凝胶，由粘蛋白、细胞碎片和 粘附性伊加。 粘液凝胶的维持是通过 杯状细胞粘液分泌的基线。 许多 病理生理状况，包括囊性纤维化和溃疡性结肠炎 结肠炎，显示粘蛋白产生/分泌改变;无生理性 然而，这些现象具有重要意义。 我们提出 为了表征粘蛋白和氧化剂生成酶的作用， 杯状细胞起源，肠过氧化物酶（IPO），在发病机制 缺血/再灌注（I/R），使用上级完全闭塞 肠系膜动脉为模型。 首先，我们将确定 鲁米那黄嘌呤氧化酶和IPO，以及它们的氧化剂，超氧化物 阴离子自由基和次卤酸，在粘膜损伤的进展中， 使用同位素和形态学终点。 二是 表征杯状细胞对I/R诱导的粘膜损伤的反应， 特别是粘蛋白和粘蛋白种类的分泌，以及 发行IPO。 我们还将确定粘蛋白的能力， AIPO产生的次卤酸，以保护上皮。 第三，我们将描述IPO的化学和生理特征， 包括：分离和化学成分;动力学，杀菌和 细胞毒性分析;以及IPO与重构的 体外粘蛋白凝胶。 最后，我们将使用从 粘蛋白和IPO的表征，试图中断 I/R诱导的体内粘膜损伤的发病机制。 使用遮挡 SMA作为模型，我们将尝试通过以下方法改善粘膜损伤： 用抗IPO抗体灭活IPO活性。 我们还将 试图用粘蛋白在体内抑制活性氧。 最后，我们将尝试模拟I/R诱导的粘膜损伤， 外源IPO和底物。 我们假设粘液凝胶 比以前认为的更通用和更有生物活性。 在正常情况下， 在某些条件下，粘蛋白-IPO相互作用会导致抗微生物屏障， 肠，但在缺血/再灌注条件下，这 免疫防御系统导致I/R诱导的粘膜损伤的开始。