Combined Activities of JNK1 and JNK2 in Hepatocytes Protect Against Toxic Liver Injury.
Combined Activities of JNK1 and JNK2 in Hepatocytes Protect Against Toxic Liver Injury.
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DOI：
10.1053/j.gastro.2015.12.019
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发表时间：
2016-04
期刊：
影响因子：
29.4
通讯作者：
Trautwein C
中科院分区：
文献类型：
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作者：
Cubero FJ;Zoubek ME;Hu W;Peng J;Zhao G;Nevzorova YA;Al Masaoudi M;Bechmann LP;Boekschoten MV;Muller M;Preisinger C;Gassler N;Canbay AE;Luedde T;Davis RJ;Liedtke C;Trautwein C
c-Jun N 末端激酶 (JNK)1 和 JNK2 在肝细胞中表达，具有重叠和不同的功能。 JNK 蛋白通过磷酸化被激活，以响应对乙酰氨基酚或 CCl4 诱导的肝损伤；激活水平与损伤程度相关。 SP600125 是一种 JNK 抑制剂，据报道可以阻止对乙酰氨基酚引起的肝损伤。我们研究了 JNK 在患者肝组织和肝细胞中 JNK 基因缺失的小鼠肝组织中的药物性肝损伤 (DILI) 中的作用。我们研究了从德国 DILI 生物库收集的 DILI 患者（由于对乙酰氨基酚、苯丙香豆素、非甾体抗炎药或自身免疫性肝炎）或无急性肝衰竭患者（对照）的肝脏切片。通过免疫组织化学和蛋白质印迹法测量总 JNK 和活化（磷酸化）JNK 的水平。肝细胞特异性删除 Jnk1 (Jnk1Δhepa) 或 Jnk1 和 Jnk2 组合 (JnkΔhepa) 的小鼠，以及 Jnk1-floxed C57BL/6（对照）小鼠，注射 CCl4（诱导纤维化）或对乙酰氨基酚（诱导中毒性肝损伤）。我们进行了基因表达微阵列和磷酸化蛋白质组学分析，以确定肝细胞中 JNK 活性的机制。与健康组织相比，DILI 患者的肝脏样本中含有更多的活化 JNK，主要存在于肝细胞核和免疫细胞中。根据血清标志物水平以及肝组织的显微镜和组织学分析，对 JnkΔhepa 小鼠施用对乙酰氨基酚比在 Jnk1Δhepa 或对照小鼠中观察到的肝损伤程度更高。与 Jnk1Δhepa 或对照小鼠相比，CCl4 的施用还诱导 JnkΔhepa 小鼠出现更严重的肝损伤，原因是炎症、细胞增殖和纤维化进展增加。给予对乙酰氨基酚的 JnkΔhepa 小鼠的肝细胞氧化应激反应增强，导致 AMPK 活化、总蛋白 AMPK 水平和 pJunD 降低以及随后的坏死。在对乙酰氨基酚之前或与对乙酰氨基酚一起施用 SP600125 可保护 JnkΔhepa 和对照小鼠免受肝损伤。在肝细胞中，JNK1 和 JNK2 似乎具有联合作用，可以保护小鼠免受 CCl4 和对乙酰氨基酚诱导的肝损伤。研究这两种蛋白（而不仅仅是 JNK1）在中毒性肝损伤发生过程中的组织特异性功能非常重要。 SP600125 抑制 JNK 显示出脱靶效应。
c-Jun N-terminal kinase (JNK)1 and JNK2 are expressed in hepatocytes and have overlapping and distinct functions. JNK proteins are activated, via phosphorylation, in response to acetaminophen- or CCl4-induced liver damage; the level of activation correlates with the degree of injury. SP600125, a JNK inhibitor, has been reported to block acetaminophen-induced liver injury. We investigated the role of JNK in drug-induced liver injury (DILI) in liver tissues from patients and in mice with genetic deletion of JNK in hepatocytes. We studied liver sections from patients with DILI (due to acetaminophen, phenprocoumon, non-steroidal anti-inflammatory drugs or autoimmune hepatitis), or patients without acute liver failure (controls), collected from a DILI Biobank in Germany. Levels of total and activated (phosphorylated) JNK were measured by immunohistochemistry and western blotting. Mice with hepatocyte-specific deletion of Jnk1 (Jnk1Δhepa) or combination of Jnk1 and Jnk2 (JnkΔhepa), as well as Jnk1- floxed C57BL/6 (control) mice, were given injections of CCl4 (to induce fibrosis) or acetaminophen (to induce toxic liver injury). We performed gene expression microarray, and phosphoproteomic analyses to determine mechanisms of JNK activity in hepatocytes. Liver samples from DILI patients contained more activated JNK, predominantly in nuclei of hepatocytes and in immune cells, than healthy tissue. Administration of acetaminophen to JnkΔhepa mice produced a greater level of liver injury than that observed in Jnk1Δhepa or control mice, based on levels of serum markers and microscopic and histologic analysis of liver tissues. Administration of CCl4 also induced stronger hepatic injury in JnkΔhepa mice, based on increased inflammation, cell proliferation, and fibrosis progression, compared to Jnk1Δhepa or control mice. Hepatocytes from JnkΔhepa mice given acetaminophen had an increased oxidative stress response, leading to decreased activation of AMPK, total protein AMPK levels, and pJunD and subsequent necrosis. Administration of SP600125 before or with acetaminophen protected JnkΔhepa and control mice from liver injury. In hepatocytes, JNK1 and JNK2 appear to have combined effects in protecting mice from CCl4- and acetaminophen-induced liver injury. It is important to study the tissue-specific functions of both proteins, rather than just JNK1, in the onset of toxic liver injury. JNK inhibition with SP600125 shows off-target effects.