The role of MKP-1/MAPK in hepatocytes and macrophages in alcohol-associated liver disease pathogenesis

Project Summary Alcohol-associated liver disease (ALD) is responsible for nearly half of all deaths from liver disease. Despite the severity of this disease, there remain no FDA-approved treatments for any stage of the disease, highlighting the critical need to elucidate the underlying mechanisms of ALD progression to develop new therapies. Mitogen-activated protein kinase phosphatase 1 (MKP-1) is the archetypal member of the dual- specificity phosphatases with a pivotal role in organ inflammation and injury, including in the liver. Earlier work showed that decreased MKP-1 levels are associated with the activation of c-Jun N-terminal kinase (JNK), which triggers an apoptotic cascade leading to alcohol induced liver injury. However, the exact mechanisms of how MKP-1 downregulation leads to hepatocyte injury and/or inflammation in ALD are known. Moreover, the role of MKP-1 in macrophages and MAPK-driven inflammation in ALD has never been examined. Our preliminary studies show that MKP-1 deletion in hepatocytes augments alcohol-induced liver injury is a NIAAA chronic plus binge model of ALD. Data also suggest that MKP-1 deletion in hepatocytes sensitizes them to TNFα induced toxicity. As an aspiring scientist whose goal is to pursue a career in alcohol-related multi-organ pathology, investigating new players in ALD pathogenesis would not only help fill this medical need but also serve as an excellent platform from which to learn how to become a successful scientist. With the help and supervision of my mentors Dr. Gobejishvili (an expert in basic research on ALD) and Dr. McClain (an expert on clinical aspects of the disease) as well as several knowledgeable collaborators, I will investigate the role of alcohol-associated downregulation of MKP-1 in the pathogenesis of ALD. The first aim of this study is to further characterize the role of MKP-1 deletion in hepatocytes using hepatocyte specific MKP-1 knpockout mice in two different mouse models of ALD. I will isolate hepatocytes and immune cells from these models, examine the effect of MKP-1 deletion on pro-inflammatory chemokine production and immune cell phenotype and describe changes in hepatocyte and immune cell health and function. The second aim will determine the role of MKP-1 specifically in macrophages using RAW 264.7 macrophage cell line, primary Kupffer cells and macrophage- specific knockout mice. To complete this research, I will follow a detailed training plan laid out for me by my co- mentors and pursue my career goals. These include, among others, continuing my didactic training in areas relevant to my research, gaining experience in new laboratory techniques, developing effective written and oral communication skills, and building a professional network of scientists. Collectively, the training and research proposed here will not only fill a significant need for the development of ALD treatments but will also foster my development from a young scientist to a successful, independent investigator in the field of alcohol-induced organ disease.