University of Southern California Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9121, USA.
Isis Pharmaceuticals, Carlsbad, CA 92008-7326.
Hepatology. 2014 Apr;59(4):1543-1554. doi: 10.1002/hep.26625. Epub 2014 Mar 3.
This study examines the role of protein kinase C (PKC) and AMP-activated kinase (AMPK) in acetaminophen (APAP) hepatotoxicity. Treatment of primary mouse hepatocytes with broad-spectrum PKC inhibitors (Ro-31-8245, Go6983), protected against APAP cytotoxicity despite sustained c-jun-N-terminal kinase (JNK) activation. Broad-spectrum PKC inhibitor treatment enhanced p-AMPK levels and AMPK regulated survival-energy pathways including autophagy. AMPK inhibition by compound C or activation using an AMPK activator oppositely modulated APAP cytotoxicity, suggesting that p-AMPK and AMPK regulated energy survival pathways, particularly autophagy, play a critical role in APAP cytotoxicity. Ro-31-8245 treatment in mice up-regulated p-AMPK levels, increased autophagy (i.e., increased LC3-II formation, p62 degradation), and protected against APAP-induced liver injury, even in the presence of sustained JNK activation and translocation to mitochondria. In contrast, treatment of hepatocytes with a classical PKC inhibitor (Go6976) protected against APAP by inhibiting JNK activation. Knockdown of PKC-α using antisense (ASO) in mice also protected against APAP-induced liver injury by inhibiting JNK activation. APAP treatment resulted in PKC-α translocation to mitochondria and phosphorylation of mitochondrial PKC substrates. JNK 1 and 2 silencing in vivo decreased APAP-induced PKC-α translocation to mitochondria, suggesting PKC-α and JNK interplay in a feed-forward mechanism to mediate APAP-induced liver injury.
PKC-α and other PKC(s) regulate death (JNK) and survival (AMPK) proteins, to modulate APAP-induced liver injury.
本研究探讨了蛋白激酶 C（PKC）和 AMP 激活的蛋白激酶（AMPK）在对乙酰氨基酚（APAP）肝毒性中的作用。尽管持续激活 c-jun-N-末端激酶（JNK），广谱 PKC 抑制剂（Ro-31-8245、Go6983）处理原代小鼠肝细胞可防止 APAP 细胞毒性。广谱 PKC 抑制剂处理可增强 p-AMPK 水平和 AMPK 调节的存活能量途径，包括自噬。用化合物 C 抑制 AMPK 或用 AMPK 激活剂激活 AMPK 相反地调节 APAP 细胞毒性，表明 p-AMPK 和 AMPK 调节能量存活途径，特别是自噬，在 APAP 细胞毒性中起关键作用。Ro-31-8245 处理可上调 p-AMPK 水平，增加自噬（即增加 LC3-II 形成、p62 降解），并防止 APAP 引起的肝损伤，即使在持续激活 JNK 和向线粒体易位的情况下也是如此。相比之下，用经典 PKC 抑制剂（Go6976）处理肝细胞可通过抑制 JNK 激活来防止 APAP。用反义寡核苷酸（ASO）在小鼠中敲低 PKC-α 也可通过抑制 JNK 激活来防止 APAP 引起的肝损伤。APAP 处理导致 PKC-α向线粒体易位和线粒体 PKC 底物磷酸化。体内 JNK1 和 2 沉默可减少 APAP 诱导的 PKC-α向线粒体的易位，表明 PKC-α 和 JNK 之间存在正反馈机制相互作用，以介导 APAP 引起的肝损伤。
PKC-α 和其他 PKC（s）调节死亡（JNK）和存活（AMPK）蛋白，以调节 APAP 引起的肝损伤。
