Project Summary/Abstract Excessive alcohol drinking modulates the innate and adaptive immune systems. It is associated with gut dysbiosis and bacterial overgrowth. Consequently, it induces intestinal permeability and microbial translocation to the liver which triggers inflammation aggravating alcohol-associated liver disease. The immune system interacts, tolerates, and shapes the intestinal microbiota while monitoring for pathogens. The balance between gut tolerance and immunity is critical in the regulation of intestinal homeostasis. A balanced intestinal homeostasis is essential to prevent intestinal permeability and microbial translocation to the liver. Goblet cells regulate the intestinal immune response by secreting mucin and presenting luminal antigens to lamina propria dendritic cells (LP-DCs) through goblet-cell associated antigen passages (GAPs). LP-DCs adjacent to GAPs have preferential tolerogenic properties. Chronic alcohol overuse decreases the pool of myeloid DCs and modifies its properties. However, the effect of chronic ethanol overuse on the LP-immune response is not well characterized. The hypothesis is that chronic ethanol exposure alters goblet cell biology resulting in the dysfunction of LP-DCs with tolerogenic properties adjacent to GAPs. Hence, a lack of antigen presentation to tolerogenic LP-DCs would induce an imbalance of the intestinal homeostasis. Therefore, goblet cells might have a central role in the onset of alcohol-related liver diseases. To explore the proposed hypothesis, aim 1 will investigate the impact of chronic alcohol abuse on goblet cell biology. It will assess goblet cell numbers, GAP formation, mucin secretion, and the consequent alterations in the LP-immune system in mice and humans. Aim 2 will define the impact of GAPs and mucin from goblet cells on ethanol-induced liver disease in ethanol-fed mice with both, loss and gain of function approaches. Finally, aim 3 will explore a pharmacological approach to manipulate goblet cells to prevent ethanol-induced liver disease in mice subjected to chronic ethanol feeding. This pharmacological intervention will induce LP-DCs with tolerogenic properties by stimulating GAP formation to regulate the mucosal immune system. The proposed study will characterize the role of goblet cells in preclinical models of ethanol-induced liver disease and patients with alcohol use disorder using cutting edge microbiomics and state-of-the-art technology. The proposed intervention will find innovative strategies to prevent alcohol-associated liver disease in patients.