Acute pancreatitis is a disease that causes debilitating illness and death, yet its pathogenetic basis at the cellular level remains poorly understood. The long-term goals of this project are to understand how the activation of the transcription factors AP-1 and NFKB in the pancreas might be important in the pathogenesis of acute pancreatitis. Whereas both of these regulatory pathways are activated by oxygen radical-mediated mechanisms, activation of AP-1 generally leads to a cytoprotective response and activation of NFKB can lead to a destructive inflammatory response. The first specific aim is to test the hypothesis that drugs that cause pancreatitis undergo oxidative metabolism within the pancreas resulting in the generation of reactive oxygen intermediates. Intracellular hydrogen peroxide production will be measured in isolated mouse pancreatic acinar cells exposed to drugs which cause acute pancreatitis clinically or experimentally (e.g. azathioprine, 6-mercaptopurine (6-MP), cerulein). The pro-oxidative and antioxidant mechanisms of the acinar cell will be either inhibited or augmented to establish their respective roles in drug- induced oxidant stress in the pancreas. The second specific aim is to test the hypothesis that drug-induced oxidant stress and altered glutathione homeostasis (depletion or oxidation) regulate transcription factor activation in the pancreas. The activation of AP-1 and NFKB will be measured in pancreatic nuclear protein extracts from mice treated with azathioprine, 6-MP or cerulein to establish whether depletion of glutathione, alteration of the glutathione red ox ratio, production of glutathione conjugates, or generation of oxygen radicals leads directly to the activation of these transcription factors. The third specific aim is to test the hypothesis that activation of AP-1 stimulates glutathione synthesis, and activation of NFKB induces the expression of proinflammatory cytokines and vascular leukocyte adhesion molecules during drug-induced acute pancreatitis. The expression of specific cytoprotective and pro-inflammatory proteins will be measured during the evolution of drug-induced pancreatitis in mice. Northern blot analysis of pancreatic mRNA and in situ hybridization techniques will be used to define the overall expression and cellular localization of expressed transcripts. Immunofluorescent techniques will be used to localize the expression of leukocyte adhesion molecules. The role of chemotactic protein KC expression in pancreatic inflammation and pancreatitis will be established by using a specific anti-murine KC blocking antibody in the mouse models of cerulein and azathioprine-induced acute pancreatitis. The new information provided by the experiments proposed here regarding the mechanisms of pancreatic nuclear transcription factor activation and its sequelae in models of drug-induced injury will be relevant to acute pancreatitis in general. Only with such detailed mechanistic information will specific prevention and treatment strategies be possible for acute pancreatitis, both drug-induced and otherwise.
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