Mechanisms Of Drug-induced Toxicities

药物引起的毒性机制

• 批准号: 6966876
• 负责人: Lance R Pohl
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6966876
• 关键词: Kupffer' s cell; acetaminophen; acetylcysteine; cytokine; cytoprotection; cytotoxicity; drug adverse effect; genetically modified animals; heat shock proteins; hepatotoxin; inflammation; interleukin 13; laboratory mouse; liver toxic disorder; microarray technology; pharmacokinetics

We have continued our studies of the molecular basis of drug-induced liver disease (DILD), which is a rare but often life-threatening toxicity. It is the major cause of acute liver failure and a principal reason drugs are withdrawn from clinical use. We have hypothesized that the idiosyncratic nature of this disease is due in part to a deficiency in hepatoprotective factors. This idea has been explored in the following ways this year: 1. We tested whether IL-13 can protect against DILD by pretreating mice with IL-13 neutralizing antibody prior to the administration of a hepatotoxic dose of acetaminophen (APAP). The neutralizing antibody significantly exacerbated liver injury up to 24 hours after APAP treatment. This finding was confirmed by showing that IL-13 knockout mice were more susceptible than wild type mice to APAP-induced liver injury. 2. We explored the mechanism of N-acetyl-L-cysteine (NAC) protection against APAP-induced liver disease, an antidote used in clinical medicine. This was done by investigating the genome-wide changes in hepatic mRNA expression following NAC rescue of mice from liver injury caused by APAP treatment. Microarray analyses revealed that NAC treatment induced the increased expression of several potential hepatoprotectic factors including heat shock proteins, acute phase phase proteins, and cell cycle regulation genes. 3. We investigated the polygenicity of DILD by comparing the liver proteomes of resistant (SJL) and susceptible (C57Bl/6) strains of mice to APAP-induced liver injury with the use of isotope-coded affinity tag (ICAT) mass spectrometry. The results revealed that SJL mice had higher levels of several proteins that could potentially protect the liver from injury. These included peroxiredoxins, stress response proteins, and hepatic growth factors. There also was a loss of mitochondrial proteins from the livers of the C57Bl/6 mice, supporting the hypothesis that mitochondria is a target of the reactive metabolite of APAP and has a significant role in APAP-induced liver injury. 4. Current evidence indicates that DILD is often caused by an allergic response (drug-induced allergic hepatitis, DIAH) induced by hepatic drug-protein adducts. The low incidence of DIAH and inability to reproduce it in animals suggests that tolerogenic mechanisms may prevent DIAH from occurring in most people and animals. We have obtained evidence to support this idea. When mice were treated with APAP, histological and flow cytometric analyses of the lymphoid organs (thymus, spleen, and lymph nodes) revealed a marked lymphocytolysis in both the T- and B-cell zone areas that was attributed in part to apoptosis. No signs of lymphocytolysis were apparent in the absence of significant hepatotoxicity. The decrease in cells in the lymphoid organs was associated with an increase of mononuclear cells infiltrating the liver that had depressed levels of several cytokines. These findings suggest that the widespread lymphocytolysis following a hepatotoxic dose of APAP may inhibit an adaptive immune response to APAP-protein adducts, thereby accounting for the lack of APAP-induced allergic reactions in most patients. Similar processes may occur with other drugs that cause liver injury.

我们继续研究药物性肝病 (DILD) 的分子基础，这是一种罕见但往往危及生命的毒性。它是急性肝衰竭的主要原因，也是药物退出临床使用的主要原因。我们假设这种疾病的特殊性质部分是由于保肝因子的缺乏造成的。今年，我们通过以下方式探索了这一想法： 1. 我们通过在给予肝毒性剂量的对乙酰氨基酚 (APAP) 之前用 IL-13 中和抗体预处理小鼠来测试 IL-13 是否可以预防 DILD。 APAP 治疗后 24 小时内，中和抗体显着加剧肝损伤。这一发现得到了证实，IL-13 敲除小鼠比野生型小鼠更容易受到 APAP 诱导的肝损伤。 2. 我们探讨了 N-乙酰基-L-半胱氨酸 (NAC) 预防 APAP 引起的肝病的机制，这是一种临床医学中使用的解毒剂。这是通过研究 NAC 拯救小鼠免受 APAP 治疗引起的肝损伤后肝脏 mRNA 表达的全基因组变化来完成的。微阵列分析显示，NAC 治疗诱导了几种潜在保肝因子的表达增加，包括热休克蛋白、急性期蛋白和细胞周期调节基因。 3.我们通过使用同位素编码亲和标签（ICAT）质谱法比较APAP诱导的肝损伤的抗性（SJL）和易感（C57Bl/6）小鼠的肝脏蛋白质组，研究了DILD的多基因性。结果显示，SJL 小鼠体内的多种蛋白质水平较高，这些蛋白质可能会保护肝脏免受损伤。这些包括过氧化还原蛋白、应激反应蛋白和肝生长因子。 C57Bl/6 小鼠肝脏中也存在线粒体蛋白的损失，这支持了这样的假设：线粒体是 APAP 反应性代谢物的靶标，并且在 APAP 诱导的肝损伤中发挥重要作用。 4. 目前的证据表明，DILD通常是由肝脏药物-蛋白加合物引起的过敏反应（药物性过敏性肝炎，DIAH）引起的。 DIAH 的发病率低且无法在动物中繁殖，这表明耐受机制可能会阻止大多数人和动物发生 DIAH。我们已经获得了支持这一想法的证据。当小鼠接受 APAP 治疗时，淋巴器官（胸腺、脾脏和淋巴结）的组织学和流式细胞术分析显示 T 细胞和 B 细胞区均出现明显的淋巴细胞溶解，部分原因是细胞凋亡。在没有显着肝毒性的情况下，没有明显的淋巴细胞溶解迹象。淋巴器官中细胞的减少与浸润肝脏的单核细胞的增加有关，而肝脏中的一些细胞因子的水平降低。这些发现表明，肝毒性剂量的 APAP 后广泛的淋巴细胞溶解可能会抑制对 APAP 蛋白加合物的适应性免疫反应，从而解释了大多数患者缺乏 APAP 诱导的过敏反应。其他引起肝损伤的药物也可能发生类似的过程。