INFLAMM. /APOPTOSIS--EXPERIMENTAL HEMOLYTIC UREMITIC SYN

炎症。

• 批准号: 7019988
• 负责人: BRUCE E. MAGUN
• 金额: $ 22.12万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7019988
• 关键词: apoptosis; biological signal transduction; cell type; cysteine endopeptidases; disease /disorder model; enzyme inhibitors; gene expression; gene induction /repression; hemolytic anemia; inflammation; laboratory mouse; lipopolysaccharides; macrophage; microarray technology; polymerase chain reaction; protein biosynthesis; renal failure; renal glomerulus; ricin; shiga toxin

DESCRIPTION (provided by applicant): Hemolytic-uremic syndrome (HUS) is the most common cause of renal failure in children. HUS is a severe inflammatory disease, caused by Shiga toxin-producing E. coli, and is marked by the expression of proinflammatory mediators within the kidneys. Shiga toxin is a member of a large family of ribotoxins whose toxicity to cells stems from the depurination of a single adenine within the "sarcin/ricin" loop of 28S ribosomal RNA (28S rRNA). The depurination of 28S rRNA results not only in the inhibition of protein translation, but also the intense and extended activation of the stress-activated protein kinases such as JNK and p38 MAPK. These kinases are central mediators of inflammatory responses that are responsible for inducing the transcription of proinflammatory cytokines and chemokines. An insufficient understanding of the primary target tissues of Shiga toxins and the mechanisms that drive the proinflammatory and cytotoxic responses has impeded the development of interventional remedies for HUS. The administration of Shiga toxins to experimental animals such as rats and mice has failed to recapitulate the renal hallmarks of HUS that involve glomerular pathologies. We have developed a mouse model of HUS that is induced by administration of ricin, a ribotoxin that has an identical ribosomal target as Shiga toxins, but that binds to receptors present on all cells. We will employ ricin in mice and primary cultured cells (macrophages and cells derived from glomeruli) to elucidate the initial targets of action, the cytotoxic consequences, and the cellular and molecular mechanisms that lead to HUS. I. We will determine the activation of gene expression induced by ricin and LPS in glomeruli in experimental HUS, in wild-type mice and in mice that are deficient in TNF and IL-I receptors: II. We will determine the genes that are activated, and the signaling pathways involved, in cultured cells of the renal glomerulus. III. We will characterize the apoptotic mechanisms in experimental HUS by elucidating the involvement of apical caspase 8 and by determining whether caspase inhibitors can ameliorate the cytotoxic consequences of ricin administration.

描述（由申请人提供）：溶血尿毒症综合征（HUS）是儿童肾衰竭的最常见原因。 HUS 是一种严重的炎症性疾病，由产生志贺毒素的大肠杆菌引起，其特征是肾脏内促炎介质的表达。志贺毒素是核毒素大家族的一员，其对细胞的毒性源于 28S 核糖体 RNA (28S rRNA) 的“沙毒素/蓖麻毒蛋白”环内单个腺嘌呤的脱嘌呤。 28S rRNA 的脱嘌呤不仅会抑制蛋白质翻译，还会导致应激激活蛋白激酶（如 JNK 和 p38 MAPK）的强烈和长期激活。这些激酶是炎症反应的中心介质，负责诱导促炎细胞因子和趋化因子的转录。对志贺毒素的主要靶组织以及驱动促炎和细胞毒性反应的机制了解不足，阻碍了 HUS 介入疗法的开发。对大鼠和小鼠等实验动物施用志贺毒素未能重现涉及肾小球病变的 HUS 肾脏特征。我们开发了一种 HUS 小鼠模型，该模型是通过施用蓖麻毒素诱导的，蓖麻毒素是一种核毒素，与志贺毒素具有相同的核糖体靶标，但与所有细胞上存在的受体结合。我们将在小鼠和原代培养细胞（巨噬细胞和肾小球来源的细胞）中使用蓖麻毒素来阐明作用的初始目标、细胞毒性后果以及导致 HUS 的细胞和分子机制。 I.我们将确定实验性HUS、野生型小鼠和缺乏TNF和IL-I受体的小鼠的肾小球中由蓖麻毒素和LPS诱导的基因表达的激活：II。我们将确定培养的肾小球细胞中被激活的基因以及所涉及的信号通路。三．我们将通过阐明顶端 caspase 8 的参与并确定 caspase 抑制剂是否可以改善蓖麻毒素施用的细胞毒性后果来描述实验性 HUS 中的细胞凋亡机制。