Studies from our VA-supported research and that of others demonstrate a critical role for the proinflammatory cytokine, tumor necrosis factor (TNF), in the development and progression of alcoholic liver disease (ALD). Alcoholic liver disease is associated with increased oxidative stress and impaired hepatocyte 26S proteasome function. Our preliminary data demonstrate that inhibition of 26S proteasome function can sensitize hepatocytes to TNF cytotoxicity, and higher doses of proteasome inhibitors directly induce hepatocyte death. Additionally, this apoptotic death involves the induction of lysosomal membrane permeability (LMP) and is mediated by lysosomal proteases (cathepsins B and D). Based on the increasingly evident role of cathepsins as key downstream mediators of apoptosis and our preliminary results, we postulate that chronic alcohol abuse with subsequent proteasome dysfunction leads to LMP and release of lysosomal cathepsins which induce hepatocyte cell death and further sensitize hepatocytes to TNF-mediated hepatotoxicity. Neutrophil infiltration is a hallmark of alcoholic hepatitis, and infiltrating neutrophils are thought to play an etiologic role in the liver injury in ALD. We recently demonstrated that inhibition of proteasome function in hepatocytes induces and markedly enhances the TNF-inducible expression of the pro-inflammatory and neutrophil chemotactic cytokine, Interleukin-8 (IL-8). It is our working hypothesis that chronic alcohol abuse mediated proteasome dysfunction is associated with increased hepatocyte IL-8 production, which significantly contributes to neutrophil infiltration and hepatic injury in ALD. The overall objective of this proposal is to elucidate the cellular and molecular mechanism(s) involved in proteasome dysfunction-mediated hepatic injury associated with ALD. The specific objectives of this proposal are to: 1) Determine the effects of proteasome inhibition and ethanol on sensitization to TNF hepatotoxicity, 2) Determine the role of lysosomal membrane permeability and cathepsins B and D in the proteasome dysfunction-mediated hepatocyte apoptosis and sensitization to TNF hepatotoxicity, and 3) Determine the effects of proteasome inhibition and ethanol on the hepatocyte expression of the critical neutrophil chemotactic CXC cytokine IL-8. Potential Impact on Veterans Health: Alcoholic liver disease is a leading cause of death from liver disease in the United States and in the Veterans Administration. In studies from the Veterans Administration, patients with cirrhosis and superimposed alcoholic hepatitis had > 60% mortality over a 4 year period of time, with most of those deaths occurring in the first month. Thus, the prognosis for this disease is more ominous than for many common types of cancer such as breast, prostate, and colon. The longterm goals of this laboratory are to define mechanism(s) for liver cell death in ALD that will provide new insights into this process and provide new areas for therapeutic intervention> This is especially important in ALD where there is no FDA-approved therapy. The potential clinical impact of this work is high.

Public Health Relevance

The overall objective of this proposal is to elucidate the cellular and molecular mechanism(s) involved in alcohol and proteasome dysfunction-mediated hepatic injury associated with alcoholic liver disease (ALD). We expect that the results of our study will provide critical molecular insights into the pathogenesis of ALD, and provide a basis for clinically relevant paradigms for future development of potential therapeutic intervention(s) in patients with ALD.

Agency
National Institute of Health (NIH)
Institute
Veterans Affairs (VA)
Type
Non-HHS Research Projects (I01)
Project #
5I01BX000350-02
Application #
7784484
Study Section
Gastroenterology (GAST)
Project Start
2009-04-01
Project End
2013-09-30
Budget Start
2010-04-01
Budget End
2011-09-30
Support Year
2
Fiscal Year
2011
Total Cost
Indirect Cost
Name
Louisville VA Medical Medical Center
Department
Type
DUNS #
086765245
City
Louisville
State
KY
Country
United States
Zip Code
40206
Kharbanda, Kusum K; Ronis, Martin J J; Shearn, Colin T et al. (2018) Role of Nutrition in Alcoholic Liver Disease: Summary of the Symposium at the ESBRA 2017 Congress. Biomolecules 8:
Schuster, Susanne; Johnson, Casey D; Hennebelle, Marie et al. (2018) Oxidized linoleic acid metabolites induce liver mitochondrial dysfunction, apoptosis, and NLRP3 activation in mice. J Lipid Res 59:1597-1609
Vatsalya, Vatsalya; Kong, Maiying; Cave, Matthew C et al. (2018) Association of serum zinc with markers of liver injury in very heavy drinking alcohol-dependent patients. J Nutr Biochem 59:49-55
Warner, Dennis R; Liu, Huilin; Miller, Matthew E et al. (2017) Dietary Linoleic Acid and Its Oxidized Metabolites Exacerbate Liver Injury Caused by Ethanol via Induction of Hepatic Proinflammatory Response in Mice. Am J Pathol 187:2232-2245
Kirpich, Irina A; McClain, Craig J; Vatsalya, Vatsalya et al. (2017) Liver Injury and Endotoxemia in Male and Female Alcohol-Dependent Individuals Admitted to an Alcohol Treatment Program. Alcohol Clin Exp Res 41:747-757
Kirpich, Irina A; Miller, Matthew E; Cave, Matthew C et al. (2016) Alcoholic Liver Disease: Update on the Role of Dietary Fat. Biomolecules 6:1
Ghare, Smita S; Donde, Hridgandh; Chen, Wei-Yang et al. (2016) Acrolein enhances epigenetic modifications, FasL expression and hepatocyte toxicity induced by anti-HIV drug Zidovudine. Toxicol In Vitro 35:66-76
Kirpich, Irina A; Petrosino, Joseph; Ajami, Nadim et al. (2016) Saturated and Unsaturated Dietary Fats Differentially Modulate Ethanol-Induced Changes in Gut Microbiome and Metabolome in a Mouse Model of Alcoholic Liver Disease. Am J Pathol 186:765-76
Liu, Huilin; Beier, Juliane I; Arteel, Gavin E et al. (2015) Transient receptor potential vanilloid 1 gene deficiency ameliorates hepatic injury in a mouse model of chronic binge alcohol-induced alcoholic liver disease. Am J Pathol 185:43-54
Jin, Ran; Willment, Andrew; Patel, Shivani S et al. (2014) Fructose induced endotoxemia in pediatric nonalcoholic Fatty liver disease. Int J Hepatol 2014:560620

Showing the most recent 10 out of 13 publications