The Immune Response After Drug Induced Hepatotoxicity

项目总结 在美国，醋氨酚(APAP)过量是急性肝功能衰竭的最常见原因 因此，这是一个重要的临床问题。尽管目前的解毒剂N-乙酰半胱氨酸(NAC)是在 1970年S，早期用药有效，APAP后8小时以上疗效下降 服药过量。尽管在APAP诱导的肝损伤的机制研究方面取得了重大进展 在接下来的几十年里，没有开发出补充NAC的其他治疗方法，并且 被转送到诊所。部分问题是延迟了病人到医院的就诊时间， 损伤过程通常正在进行中，任何药物，包括针对早期过程的NAC，都可能是有限的 利益。现在已经认识到，在APAP诱导的损伤后，肝脏的再生能力是 决定患者预后的关键特征。APAP诱导对细胞的迟发性先天免疫反应 损伤，我们在小鼠和人类上的早期研究表明，免疫细胞渗透促进了 损伤细胞，有利于再生和恢复。我们最近公布的数据现在表明 Netrin-1蛋白等引导信号通过腺苷A2B受体发挥抑制作用 促进中性粒细胞和巨噬细胞渗入坏死区，以促进肝脏再生和 APAP过量用药后康复。根据最近的信息，中性粒细胞和巨噬细胞的表型 可以将细胞功能从促炎转变为抗炎，我们假设 腺苷A2B受体促进APAP过量用药后免疫细胞介导的肝恢复 一种有效的抗APAP肝毒性的迟效治疗方法。这一假设将是 通过1)阐明巨噬细胞募集和肝再生的分子机制进行测试 体内APAP过量后腺苷A2B受体激活及其对恢复的促进作用2) 腺苷A2B受体的药理调节及缺失对血管内皮细胞生长的影响 3)探讨A2BAR激动剂和天然免疫应答的作用 延长NAC后，评估APAP过量用药后患者的循环单核细胞标志物。我们有 APAP过量的先进早期作用替代疗法，如4-甲基吡唑(4MP)通过Pre-Pre 临床动物实验和志愿者安全性研究，以规划临床试验。而4MP的功能是 预防APAP引起的损伤，对于严重过量服药的患者将是有益的，预计 本文提出的研究结果将为A2B受体作为一种可能的靶标提供新的见解。 在临床上补充4MP和NAC的迟效治疗并改善APAP后的预后 服药过量。

PROJECT SUMMARY Acetaminophen (APAP) overdose is the most common cause of acute liver failure in the United States and thus is an important clinical problem. Though the current antidote N-acetylcysteine (NAC) was developed in the 1970's and is effective if administered early, its efficacy decreases if given beyond 8 hours after an APAP overdose. In spite of the significant progress in understanding mechanisms of APAP-induced liver injury in the subsequent decades, no additional therapeutic approaches to complement NAC have been developed and translated to the clinic. Part of the problem is the delayed presentation of patients to the hospital, by which time the injury process is often in progress and any drugs including NAC targeting early processes may be of limited benefit. It is now recognized that the regenerative capacity of the liver subsequent to APAP-induced injury is a critical feature dictating patient prognosis. APAP induces a late innate immune reaction in response to cell injury, and our early studies in mice and humans indicated that immune cell infiltration facilitated removal of damaged cells and was helpful in regeneration and recovery. Our recently published data now indicate that guidance cues such as the protein netrin-1 function through the adenosine A2B receptor to suppress neutrophils and enhance macrophage infiltration into the necrotic area to facilitate liver regeneration and recovery after an APAP overdose. Based on recent information that neutrophil and macrophage phenotypes can shift cell functionality from pro-inflammatory to anti-inflammatory, we hypothesize that activation of the adenosine A2B receptor enhances immune-cell mediated liver recovery after APAP overdose and this could be an effective late-acting therapeutic approach against APAP-induced hepatotoxicity. This hypothesis will be tested by 1) Elucidating molecular mechanisms involved in macrophage recruitment and liver regeneration after activation of the adenosine A2B receptor and their facilitation of recovery after APAP overdose in vivo, 2) Examining the effects of pharmacological modulation as well as deficiency of the adenosine A2B receptor on APAP-induced liver injury in vivo, and 3) Explore the role of A2BAR agonists and the innate immune response after prolonged NAC and evaluate circulating monocyte markers from patients after APAP overdose. We have advanced early acting alternative therapies for APAP overdose such as 4-methylpyrazole (4MP) through pre- clinical animal experiments and volunteer safety studies to planning of a clinical trial. While 4MP functions to prevent APAP-induced injury and would be beneficial in patients with severe overdose, it is anticipated that results from the studies proposed here will provide novel insight into the A2B receptor as a putative target for a late acting therapeutic to complement 4MP and NAC in the clinic and improve outcomes after an APAP overdose.