Project Summary Alcoholic liver diseases (ALD) -- ranging from alcoholic fatty liver to alcohol-induced liver fibrosis and cirrhosis - - account for more than 50% of all chronic liver diseases in western countries and are responsible for 5% of the deaths occurring annually in the United States including our Veteran population. Studies have shown that while all heavy drinkers display signs of hepatitis steatosis (fatty liver); only 10% to 35% of alcoholics develop hepatic inflammation, with up to 20% progressing to cirrhosis. About 15% of U.S. alcoholics eventually will develop alcoholic liver diseases, one of the leading causes of liver diseases and liver-relate death worldwide. The clinical spectrum of alcoholic liver disease includes alcoholic fatty liver, alcoholic steatohepatitis, alcoholic cirrhosis, and increased risk of hepatocellular carcinoma. The pathological mechanisms of ALD involves complex interactions between the direct effects of alcohol and its toxic metabolites on various cell types in the liver, induction of reactive oxygen species (ROS), upregulation of the inflammatory cascade, and other cell-specific effects in the liver. The field of non-coding RNA (ncRNA) molecules represents a paradigm shift in biology, away from the central dogma of biology which places RNA molecules as mere messengers between DNA and protein synthesis. However, more than 90% of the RNA molecules made by a cell are not destined to be translated into proteins. Instead, these ncRNAs can act as enzymes, signaling molecules and transcriptional factors. MicroRNAs (miRNAs) are small ncRNAs that have been recently identified as master regulators of the cellular transcriptome and proteome. miRNAs play a crucial role in shaping the differentiation and function of tissues and organs in both health and disease. Several recent studies have provided compelling evidence showing that ethanol-sensitive miRNAs are indeed regulatory master-switches. More specifically, miRNAs control the development of tolerance, a crucial component of ethanol addiction. Other drugs of abuse also target some ethanol-sensitive miRNAs suggesting that common biochemical mechanisms underlie addiction. Therefore, the knowledge of the precise mechanisms of ncRNA regulation in ALD becomes very critical to develop therapeutic interventions since the failing liver may revive if given proper support in a timely manner. Our long-term goal is to clarify the mechanisms underlying the abnormal intercellular communication of ncRNAs that lead to ALD. In this application, we propose the systematic investigation of ethanol and endotoxin (lipopolysaccharide, LPS) dependent ncRNAs as ALD markers by focusing on four specific aims: First, we will identify the functional ethanol-dependent miRNAs involved in cell survival in human hepatic stellate cells, hepatocytes and cholangiocytes. Second, we will define the role of LPS regulated miRNAs in human hepatic stellate and parenchymal cells and the related remodeling mechanisms. Third, we will evaluate the cross-talk between specific transcribed ultra conserved regions (T-UCRs) and miR- 181/let-7 families, and define the role of this interaction in ALD properties in hepatobiliary epithelial and stellate cells. Fourth, we will determine the effects of ethanol and LPS dependent ncRNAs on the progression of ALD in a mouse model of alcoholic steatohepatitis in vivo. The identification of miRNAs as an important regulator of hepatic cell survival, transformation and remodeling in vitro, as well as their upstream modulators and interaction with T-UCRs will provide insight into the involvement of altered ncRNA expression in contributing to ALD progression and test novel therapeutic approaches for ALD in animal models.
NIH ExPorter
NIH ExPorter