Alcohol-related liver disease (ALD) is a major health problem and a leading cause for liver disease-related mortality worldwide, claiming more than 3 million deaths, or 5.9% of all deaths globally per year. ALD comprises a range of disorders and pathologic changes in individuals with acute and chronic alcohol consumption, ranging from simple steatosis to severe forms of liver injury including steatohepatitis, liver fibrosis/cirrhosis, and hepatocellular carcinoma (HCC). While decades of research have enriched our understanding on the pathogenesis of ALD, therapeutic options for ALD treatment are still very limited. So far, alcohol abstinence achieved by psychosomatic intervention is the best treatment for all stages of ALD. No successful treatment for advanced ALD, such as cirrhosis, alcoholic hepatitis, or HCC, is available other than liver transplantation, which is largely due to the lack of suitable animal models to help to identify therapeutic targets. Autophagy is a lysosomal degradation pathway, which is activated as a protective mechanism for cells against various adverse conditions. We previously demonstrated that acute alcohol exposure activates autophagy as a protective mechanism in acute alcohol-induced liver injury However, acute and chronic alcohol exposure may differentially regulate hepatic autophagy. Animals with chronic ethanol exposure and human heavy drinkers develop hepatomegaly with increased hepatic protein accumulation, suggesting a possible defect in hepatic autophagy in chronic alcohol conditions. However, the mechanisms by which chronic alcohol consumption impairs autophagy and/or lysosomal functions in the liver are largely unknown. We characterized the autophagy status in a chronic feeding plus acute binge alcohol (hereafter referred to as “Gao-binge”) mouse model according to the guidelines of autophagy research (Chapter 3). We investigated the role and mechanisms of transcription factor EB (TFEB), which is a master regulator of autophagy and lysosomal biogenesis, in Gao-binge alcohol-induced liver injury. Compared with control mice, liver tissues from mice fed on the ethanol diet had lower levels of total and nuclear TFEB, and hepatocytes had decreased lysosome biogenesis and autophagy. Mechanistically, hepatocytes from mice fed on the ethanol diet had increased translocation of mechanistic target of rapamycin (mTOR) onto lysosomes, resulting in increased activation of mTOR complex 1 (mTORC1). Increased mTORC1 activation phosphorylates and inactivates TFEB resulting in decreased hepatic lysosomal biogenesis and insufficient autophagy. Administration of torin1, a specific mTOR kinase inhibitor, increased liver levels of TFEB and decreased steatosis and liver injury in mice fed with Gao-binge alcohol. Overexpression of TFEB in mouse livers increased lysosomal biogenesis and mitochondrial bioenergetics and protected against Gao-binge alcohol-induced liver injury. In contrast, genetic knockdown of Tfeb or double deletion of Tfeb and Tfe3 (another homologue of Tfeb in mammals) exacerbated Gao-binge alcohol-induced liver injury. More importantly, liver tissues from alcoholic hepatitis patients also had lower nuclear levels of TFEB than control normal human liver tissues. Results from my research presented in Chapter 3 demonstrated that chronic alcohol consumption impairs TFEB-mediated lysosomal biogenesis resulting in insufficient liver autophagy. Strategies to boost TFEB activation such as the use of mTOR inhibitor may pave a novel avenue for treating/preventing ALD. Tuberous sclerosis 1 (TSC1) forms a TSC1/2 complex with TSC2, which is a key inhibitor of mTORC1 that functions as a GTPase-activating protein (GAP) for the small Ras-related GTPase Rheb (Ras homolog enriched in brain). The active, GTP-bound form of Rheb directly interacts with and activates mTORC1. As a Rheb-specific GAP, TSC1/2 negatively regulates mTORC1 signaling by converting Rheb into its inactive GDP-bound state. In Chapter 4, we established a novel mouse model that can phenocopy the typical pathogenesis of human alcoholic hepatitis. We found Gao-binge alcohol markedly increased hepatomegaly, ductular reactions (DRs), inflammation, and liver injury in liver-specific Tsc1 knockout (L-Tsc1) KO mice compared to either Gao-binge alcohol fed WT mice or control diet-fed L-Tsc1 KO mice. Mechanistic studies revealed increased YAP and Notch activation as well as endoplasmic reticulum (ER) stress markers in alcohol-fed L-Tsc1 KO mice. In addition, we observed decreased nuclear translocation of TFEB in hepatocytes of alcohol-fed mice. In contrast, we found that nuclear TFEB translocation was significantly increased in cholangiocytes in alcohol-fed L-Tsc1 KO mice, which was independent of mTORC1 activation. Moreover, deleting Tsc1 in cholangiocyte but not in hepatocyte aggravated alcohol-induced liver injury, hepatomegaly, DR, fibrosis, and inflammation in mouse livers. Administration of torin1 partially reversed hepatic TSC1 deletion-induced hepatomegaly, DR, fibrosis, inflammatory cell infiltration and liver injury in Gao-binge alcohol-fed mice. Therefore, in Chapter 4, we established a novel advanced mouse ALD model that phenocopy human ASH. The most severe form of ALD is alcohol associated HCC wherein the role of autophagy in HCC is still controversial. Activation of cellular stress response pathways, such as autophagy, unfolded protein response in endoplasmic reticulum and mitochondria, DNA damage response, etc. to maintain metabolic homeostasis is a critical growth and survival mechanism in many cancer cells. As discussed in Chapter 3, activating TFEB protects against alcohol-induced liver injury and steatosis in early stages of ALD. However, the exact role of TFEB in alcohol-associated liver carcinogenesis in the later stages of ALD is still unknown. In Chapter 5, we investigated the role of TFEB in a diethylnitrosamine (DEN)-alcohol-induced HCC mouse model. Mice fed chronically with ethanol diet developed bigger and more liver tumors than that fed with control diet- in DEN-treated mice. There is no significant difference in the tumor numbers between WT and L-Tfeb KO mice fed with control diet or ethanol diet. But the size of the liver tumors was smaller in L-Tfeb KO mice than that in WT mice fed either the control or ethanol diets. Additionally, chronic alcohol consumption increased cell proliferation in both WT and L-Tfeb KO mouse livers. There were no significant changes in the DR, fibrosis, or inflammation in WT or L- Tfeb KO mice fed with either control diet or ethanol diet. In this chapter, we found that chronic alcohol consumption promotes carcinogen-induced liver tumor development in mice. Hepatic deletion of TFEB in mice attenuates alcohol-associated liver tumorigenesis. In summary, studies in this dissertation discovered that chronic plus binge ethanol activates hepatic mTORC1 that leads to impaired TFEB-mediated lysosomal biogenesis resulting in insufficient autophagy and liver injury. We also established a novel advanced ALD mouse model by using mice with persistent hepatic mTORC1 activation fed with Gao-binge alcohol. This mouse model phenocopied the pathogenesis of human alcoholic hepatitis including significant liver injury, hepatomegaly, DR, inflammation, fibrosis, and liver cell repopulation, which will be beneficial for the development of targeted therapy and further understanding the pathogenesis of severe ALD. Finally, we determined the role of TFEB in an alcohol-associated HCC mouse model. We found that hepatic TFEB deficiency slightly attenuates alcohol-associated liver tumorigenesis in mice, suggesting autophagy-lysosomal pathway may be critical for liver tumor development and progression. Overall, the findings from the dissertation may provide important insights on targeting the TFEB-autophagy-lysosomal pathway in treating/preventing ALD. In the early stage of ALD before the HCC development, activation of TFEB-lysosomal pathway may be beneficial to attenuate steatosis, inflammation, DR, and liver injury of ALD. However, once HCC has been developed, perhaps, inhibition of TFEB-lysosomal pathway may only slow down alcohol-associated HCC progression.