INFLAMM. /APOPTOSIS--EXPERIMENTAL HEMOLYTIC UREMITIC SYN

描述（由申请人提供）：溶血性尿毒综合征（HUS）是儿童肾衰竭的最常见原因。溶血性尿毒综合征是由产滋贺毒素的大肠杆菌引起的严重炎症性疾病。大肠杆菌，并通过肾脏内促炎介质的表达来标记。滋贺毒素是核糖毒素大家族的成员，其对细胞的毒性源于28 S核糖体RNA（28 S rRNA）的“八叠球菌毒素/蓖麻毒素”环内的单个腺嘌呤的脱嘌呤。28 SrRNA的脱嘌呤不仅导致蛋白质翻译的抑制，而且还导致应激激活蛋白激酶如JNK和p38 MAPK的强烈和延长的激活。这些激酶是负责诱导促炎细胞因子和趋化因子转录的炎症反应的中心介质。对滋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的认识不足阻碍了HUS干预疗法的发展。将滋贺毒素给予实验动物如大鼠和小鼠未能概括涉及肾小球病理的HUS的肾脏特征。我们已经开发了一种通过施用蓖麻毒素诱导的HUS小鼠模型，蓖麻毒素是一种核糖体靶点与滋贺毒素相同的核糖体毒素，但与所有细胞上存在的受体结合。我们将采用蓖麻毒素在小鼠和原代培养细胞（巨噬细胞和细胞来源于肾小球），以阐明最初的行动目标，细胞毒性的后果，以及导致HUS的细胞和分子机制。I.我们将确定在实验性HUS中，野生型小鼠和TNF和IL-1受体缺乏的小鼠中，由蓖麻毒素和LPS诱导的肾小球中基因表达的激活：II.我们将确定在肾小球培养细胞中被激活的基因和相关的信号通路。三.我们将通过阐明顶端半胱天冬酶8的参与和确定半胱天冬酶抑制剂是否可以改善蓖麻毒素给药的细胞毒性后果来表征实验性HUS中的细胞凋亡机制。

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.