ACETAMINOPHEN COVALENT BINDING AND HEPATOXICITY

急性过量服用解热止痛剂，对乙酰氨基酚(APAP)可以 导致严重的、致命的肝脏坏死。肝毒性是APAP的结果 激活到与肝脏蛋白质共价结合的电泳体。 虽然，APAP的蛋白质共价结合与 毒性不明，选择性芳基化一种58 kDa的APAP结合蛋白 (58-ABP)与毒性的关联比完全共价结合更好。 58-ABP是抗APAP抗体检测到的最突出的靶点 APAP对小鼠和人肝脏的毒性作用。在小鼠体内，58-ABP 芳基化与靶组织损伤(肝脏、 肺和肾)在不同的实验范式。芳基化的蛋白质是 在中毒的APAP暴露后的小鼠血浆中也检测到这种情况，这可能 镜像检测人血浆中APAP蛋白加合物 下毒了。我们的工作假设是58-ABP的芳基化是 对APAP诱导的靶器官毒性很重要。IS是否播放了一个 目前还不能解决启动或保护作用。最新结果 提出了新的问题，这些问题是拟议研究的基础。1) 是否存在58-ABP结合的阈值，如果超过该阈值，则会关联 有毒性吗？2)58-ABP是否也是其他药物的靶标 对蛋白质的共价作用？3)这种物质的毒理学意义是什么？ 血浆中芳基化58-ABP的出现？拟议的研究将 广泛使用抗APAP和抗58抗体，这是一种针对猪瘟的新抗体 58-ABP。这将允许对存在的 共价结合阈值。会产生抗体来对抗绑定 溴苯允许比较其与APAP的结合和与 溴苯中毒。用抗-58免疫沉淀将有助于 检测58-ABP与其他外源物质的结合。体外研究将 确定其他试剂是否结合在58-ABP和APAP上的同一位点，以及 培养和体内研究将揭示这种结合是否会导致中毒 在同时曝光期间的相互作用。我们还将确定是否 APAP或其他异物反应后血浆中58-ABP的出现 细胞分泌芳基化蛋白或因以下原因引起的附带损失 细胞死亡。对结合但不会造成毒性的试剂的研究将 也包括在内，以确定这些制剂是否针对相同的蛋白质 有毒化合物。总的来说，这些研究将提供新的见解 探讨APAP和其他有毒物质选择性芳基化58-ABP的重要性 用于靶器官毒性的化学品。他们还将确定是否 血浆中58-ABP的出现可作为一种有用的诊断标记物 异种生物诱导的靶器官损伤。

Acute overdosage with the antipyretic analgesic, acetaminophen (APAP) can cause severe, fatal hepatic necrosis. Hepatotoxicity is the result of APAP activation to an electrophile which covalently binds to liver proteins. Although, the relationship between APAP's protein covalent binding and toxicity is not clear, selective arylation of a 58 kDa APAP binding protein (58-ABP) is better associated with toxicity than is total covalent binding. The 58-ABP is the most prominent target detected with anti-APAP antibody in mouse and human liver during APAP hepatotoxicity. In mice, 58-ABP arylation was most closely associated with target tissue damage (liver, lung and kidney) in varied experimental paradigms. The arylated protein is also detected in mouse plasma after toxic APAP exposures, and this may mirror the detection of APAP-protein adducts in human plasma during poisoning. Our working hypothesis is that arylation of the 58-ABP is important for APAP-induced target organ toxicity. Whether is plays an initiating or protective role cannot presently be resolved. Recent results have raised new questions which are the basis of the proposed research. 1) Is there a threshold for 58-ABP binding which, if exceeded, is associated with toxicity? 2) Is the 58-ABP also targeted by other agents which bind covalently to proteins? 3) What is the toxicological significance of the appearance of arylated 58-ABP in plasma? The proposed research will extensively use anti-APAP and anti-58, a new antibody prepared against the 58-ABP. This will permit quantitative assessment of the existence of a covalent binding threshold. Antibodies will be developed against bound bromobenzene to permit comparison of its binding with APAP's and with bromobenzene toxicity. Immunoprecipitation with anti-58 will facilitate detection of 58-ABP binding by other xenobiotics. In vitro studies will determine if other agents bind at the same site on the 58-ABP and APAP, and culture and in vivo studies will reveal if such binding can cause toxic interactions during simultaneous exposures. We will also determine if the appearance of 58-ABP in plasma after APAP or other xenobiotics reflects cellular secretion of arylated protein or incidental loss as a result of cell death. Studies with agents which bind but do not cause toxicity will also be included to determine if such agents target the same proteins as the toxic compounds. Collectively such studies will provide new insight into the importance of selective 58-ABP arylation by APAP and other toxic chemicals for target organ toxicity. They will also determine if the appearance of 58-ABP in plasma can become a useful diagnostic marker for xenobiotic-induced target organ damage.