REGULATION OF EPITHELIAL PERMEABILITY BY GROWTH FACTORS

生长因子对上皮通透性的调节

• 批准号: 3244051
• 负责人: JAMES A MCROBERTS
• 金额: $ 14.83万
• 依托单位: LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1994-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3244051
• 关键词: antireceptor antibody; biological signal transduction; colitis; cytokine; cytoskeletal proteins; cytoskeleton; disease /disorder model; electrical conductance; gap junctions; gastrointestinal absorption /transport; gastrointestinal epithelium; glucose; glucose metabolism; growth factor; growth factor receptors; high performance liquid chromatography; hormone regulation /control mechanism; human tissue; inflammatory bowel diseases; insulin; insulin receptor; insulinlike growth factor; intestinal mucosa; iron; laboratory rabbit; peptide hormone metabolism; protein kinase; protein purification; radioimmunoassay; receptor binding; second messengers; tissue /cell culture

The barrier function of intestinal epithelial cells is mediated largely by tight junctions between adjacent cells. Tight junctional permeability is regulated by a number of disparate factors including several inflammatory mediators, by processes which involve changes in the cellular cytoskeleton. There is accumulating evidence that increased junctional permeability could play an important role in the etiology, progression and maintenance of chronic diarrheal and inflammatory bowel diseases. In particular, an inherited disorder in junctional permeability may predispose individuals to Crohn's disease. In order to understand the molecular basis for increased junctional permeability, a better basic understanding is needed of the physical nature of this paracellular pathway and the mechanisms and factors which regulate its permeability. This application will identify the role and mechanism of insulin and insulin-like growth factors (IGFs) in regulation of junctional permeability. Using monolayer cultures of the differentiated human colonic epithelial cell line, T84, we have shown that insulin and IGFs cause a specific, reversible and dose dependent increase in junctional permeability. Using monolayer cultures of the differentiated human colonic epithelial cell line, T84, we have shown that insulin and IGFs cause a specific, reversible and dose dependent increase in junctional permeability. Using this model system, we will investigate how these peptide hormones regulate permeability by 1) identifying the receptors which mediate the effect; 2) identifying intracellular mechanisms involved in transducing the response; and 3) identifying changes in the cellular cytoskeleton which accompany changes in permeability. We will then determine whether autocrine production of IGF-like peptides accounts for the inability of T84 cells to retain high transepithelial resistance when grown in defined, serum-free media. Completion of this aim will result in defined, serum-free media conditions useful in examining the production and response of cultured epithelial cells to other growth factors and cytokines. Finally, we will extend our observations to non-tumorigenic cell lines in culture and to tissues from rabbits with experimentally induced colitis to determine whether insulin-like growth factors are likely to mediate increased mucosal permeability in vivo. These experiments are likely to elucidate the factors and mechanisms involved in regulating junctional permeability. This could lead to a more rational approach in understanding the etiology and in improving treatment for inflammatory bowel disease.

肠上皮细胞的屏障功能在很大程度上由 相邻细胞之间的紧密连接。紧密连接渗透率是 由许多不同的因素调节，包括几个炎症性因素 介体，通过涉及细胞细胞骨架变化的过程。 越来越多的证据表明，交界处渗透性的增加可能 在糖尿病的病因、进展和维持中起重要作用 慢性腹泻和炎症性肠病。特别是，一个 遗传性连接通透性障碍可能使个体倾向于 克罗恩病。为了了解增生性疾病的分子基础 对于结合部渗透性，需要更好地基本了解 这种细胞旁途径的物理性质、机制和影响因素 调节其渗透性的物质。此应用程序将标识角色 胰岛素和胰岛素样生长因子(IGFS)的作用机制 结合部通透性的调节。使用单层培养的 分化的人结肠上皮细胞系T84，我们已经证明 胰岛素和IGFS引起特异性、可逆性和剂量依赖性的增加 在结合部渗透性方面。使用分化细胞的单层培养 人结肠上皮细胞系T84，我们已经证明胰岛素和 IGFS引起特异性、可逆性和剂量依赖性的交界区增加 渗透性。使用这个模型系统，我们将调查这些 多肽激素通过1)识别受体来调节通透性 2)确定所涉及的细胞内机制 在传递反应中；以及3)识别细胞中的变化 伴随着渗透性变化的细胞骨架。到时候我们会的 确定胰岛素样生长因子样肽的自分泌产生是否在 T84细胞不能保持较高的跨上皮抵抗 在固定的、无血清的培养基中生长。完成这一目标将导致 明确的、无血清的介质条件可用于检查生产和 培养的上皮细胞对其他生长因子的反应和 细胞因子。最后，我们将把我们的观察扩展到非致瘤性。 培养的细胞系和兔的实验组织 诱导结肠炎以确定胰岛素样生长因子是否可能 以介导体内粘膜通透性的增加。这些实验是 可能阐明参与调控的因素和机制 结合部渗透率。这可能导致一种更合理的方法 认识炎症性疾病的病因，提高治疗水平 肠病。