Activation of CD40 with Platelet Derived CD154 Promotes Reactive Oxygen Species Dependent Death of Human Hepatocytes during Hypoxia and Reoxygenation

作者：Bhogal Ricky H^*; Weston Christopher J; Curbishley Stuart M; Adams David H; Afford Simon C

来源：PLos One, 2012, 7(1): e30867.

DOI：10.1371/journal.pone.0030867

Background: Hypoxia and hypoxia-reoxygenation (H-R) are pathogenic factors in many liver diseases that lead to hepatocyte death as a result of reactive oxygen species (ROS) accumulation. The tumor necrosis factor super-family member CD154 can also induce hepatocyte apoptosis via activation of its receptor CD40 and induction of autocrine/paracrine Fas Ligand/CD178 but the relationship between CD40 activation, ROS generation and apoptosis is poorly understood. We hypothesised that CD40 activation and ROS accumulation act synergistically to drive human hepatocyte apoptosis. %26lt;br%26gt;Methods: Human hepatocytes were isolated from liver tissue and exposed to an in vitro model of hypoxia and H-R in the presence or absence of CD154 and/or various inhibitors. Hepatocyte ROS production, apoptosis and necrosis were determined by labelling cells with 2%26apos;,7%26apos;-dichlorofluorescin, Annexin-V and 7-AAD respectively in a three-colour reporter flow cytometry assay. %26lt;br%26gt;Results: Exposure of human hepatocytes to recombinant CD154 or platelet-derived soluble CD154 augments ROS accumulation during H-R resulting in NADPH oxidase-dependent apoptosis and necrosis. The inhibition of c-Jun N-terminal Kinase and p38 attenuated CD154-mediated apoptosis but not necrosis. %26lt;br%26gt;Conclusions: CD154-mediated apoptosis of hepatocytes involves ROS generation that is amplified during hypoxia-reoxygenation. This finding provides a molecular mechanism to explain the role of platelets in hepatocyte death during ischemia-reperfusion injury.

• 出版日期2012-1-25