CELLULAR MECHANISMS BY WHICH ALCOHOL PROMOTES HIV PROTEASE INHIBITOR-INDUCED HEPATOTOXICITY Michael Hinton, B.S. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University Virginia Commonwealth University, 2019 Major Director: Huiping Zhou Professor, Department of Microbiology and Immunology The development of highly-active-antiretroviral therapy(HAART) has allowed management of HIV and extended the lives of those infected. Alcohol abuse, which is very common in HIV-1 infected patients, is one of the most important co-morbid risk factors for liver injury and has been associated with the occurrence of serious metabolic syndrome and subsequent discontinuation of HAART in HIV patients. We have identified endoplasmic reticulum (ER) stress-induced proapoptotic factor CCAAT-element-binding protein homologous protein (CHOP) as an important mechanism underlying HIV PI-induced inflammation and hepatic lipotoxicity. However, little is known about the mechanistic pathways by which alcohol promotes HIV PI-induced hepatic lipotoxicity. The aim of this study was to determine if inhibition of CHOP expression prevents alcohol- and HIV PI-induced apoptosis and dysregulation of lipid metabolism. We demonstrated that co-administration of alcohol and HIV PIs induced unfolded protein response (UPR) activation, ER stress, and CHOP upregulation in rodent hepatocytes. Both alcohol and HIV PI-induced lipid accumulation and apoptosis were significantly reduced in CHOP-/- hepatocytes. Also, CHOP-/- hepatocytes treated with alcohol and HIV PIs showed inflammation.. Activation of the ER stress-induced proapoptotic factor CHOP is a key cellular mechanism underlying alcohol and HIV PI-induced hepatotoxicity. CHOP expression is key for alcohol and HIV PI-induced dysregulation of key genes involved in lipid metabolism in hepatocytes. Limitations of the study include the usage of global CHOP-/- in lieu of tissue-specific conditional knockout mouse models, nonobservance of the effects of alcohol and HIV PIs on extra-hepatic tissues, and incomplete investigation of the interplay of hepatocytes and resident macrophages.