Alcohol influences gene expression and function of polymorphonuclear cells in liver disease

Background and Aim: Alcohol is one of the major causes of liver cirrhosis worldwide. Patients with alcohol-related liver diseases are highly predisposed to infection. It is reported that, neutrophils counts are higher in peripheral blood and liver tissue of these patients. Neutrophils are the first responders to infection and tissue injury and optimal neutrophil function is important in disease resolution. Thus, our objectives were to investigate the effects of alcohol on neutrophil function, gene expression and ability to resolve infection. Methods: An in-vitro alcoholic PMN model was designed using polymorphonuclear(PMN) cells derived from healthy individuals (n=20) which were subjected to 300mg/dL ethanol treatment for 24 hours. Post alcohol treatment, gene expression of CCL20 and IL1, calcium flux estimation, ROS generation and phagocytic ability were assessed using standard protocols. In addition, re-analysis of published datasets of alcoholic liver disease was carried out. Our previously published transcriptome dataset of alcoholic ACLF vs. non-alcoholic ACLF PMN was also analyzed to see if gene expression patterns in alcoholic liver disease datasets overlapped with other diseases with alcoholic etiology. Results: The in-vitro model of alcoholic PMN showed significant upregulation of the inflammatory gene IL1 and the neutrophil derived chemokine CCL20 (p-value<0.05). This was validated in ACLF patient samples with alcoholic etiology compared to those with non-alcoholic etiology (n=15 per group). In the published transcriptomic studies also, CCL20 and IL1 were upregulated thereby forming a shared gene signature among liver diseases with alcoholic etiology. Functional assays demonstrated that alcohol exposure led to a dampening of baseline calcium flux, ROS generation as well as phagocytic ability which are critical for bacterial clearance. Conclusions: Our study shows that neutrophil response to alcohol exposure includes the upregulation of pro-inflammatory genes CCL20 and IL1 and a concomitant dampening of their bactericidal ability by lowering of calcium flux, ROS and phagocytosis.