Suppression of the interleukin-1ß-induced inflammatory response of human Chang liver cells by acute and subacute exposure to alcohol: an in vitro study

Reduced phagocytosis, ROS production and enhanced apoptosis of leukocytes upon alcohol drinking in healthy volunteers

Background

Alcohol drinking is associated with a serious risk of developing health problems as well as with a large number of traumatic injuries. Although chronic alcohol misuse is known to contribute to severe inflammatory complications, the effects of an acute alcohol misuse are still unclear. Here, the impact of acute alcohol drinking on leukocyte counts and their cellular functions were studied.

Methods

Twenty-two healthy volunteers (12 female, 10 male) received a predefined amount of a whiskey-cola mixed drink (40% v/v), at intervals of 20 min, over 4 h to achieve a blood alcohol concentration of 1‰. Blood samples were taken before drinking T₀, 2 h (T₂), 4 h (T₄), 6 h (T₆), 24 h (T₂₄) and 48 h (T₄₈) after starting drinking alcohol. Leukocytes, monocytes and granulocyte counts and their functions regarding the production of reactive oxidative species (ROS), phagocytosis and apoptosis were analyzed by flow cytometry.

Results

Total leukocyte counts significantly increased at T₂ and T₄, while granulocyte and monocyte counts decreased at T₄ and T₆ vs. T₀. Monocytes increased significantly at T₂₄ and T₄₈ vs. T₀. While the total number of ROS-producing leukocytes and notably granulocytes significantly increased, in parallel, the intracellular ROS intensity decreased at T₂ and T₆. The numbers of ROS-positive monocytes have shown a delayed modulation of ROS, with a significant reduction in the total number of ROS-producing cells at T₄₈ and a significantly reduced intracellular ROS-intensity at T₂₄. Phagocyting capacity of leukocytes significantly decreased at T₄ and T₆. In general leukocytes, and notably granulocytes demonstrated significantly increased early (T₂), while monocyte exerted significantly increased late apoptosis (T₂₄ and T₄₈).

Conclusions

Alcohol drinking immediately impacts leukocyte functions, while the impact on monocytes occurs at even later time points. Thus, even in young healthy subjects, alcohol drinking induces immunological changes that are associated with diminished functions of innate immune cells that persist for days.

Short Exposure to Ethanol Diminishes Caspase-1 and ASC Activation in Human HepG2 Cells In Vitro

This paper discusses how the assembly of pro-caspase-1 and apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) in macromolecular protein complexes, inflammasomes, activates caspase-1. The present study investigates the molecular mechanisms of inflammasome activation in HepG2 cells and examines how short exposures to ethanol (EtOH) affect inflammasome activation. HepG2 cells were treated with lipopolysaccharide (LPS), ATP or nigericin (NIG) in a two-step model. After LPS priming, ATP or NIG were added. As inhibitors, sodium orthovanadate (general inhibitor of tyrosine phosphatases), AC-YVAD-CMK (caspase-1 inhibitor) or AZ10606120 (purinergic receptor P2X7R inhibitor) were applied after LPS priming. To monitor the inflammasome activation, the caspase-1 activity, ASC speck formation, reactive oxygen species (ROS) production and cell death were analyzed. To elucidate the mechanistical approach of EtOH to the inflammasome assembly, the cells were treated with EtOH either under simultaneous LPS administration or concurrently with ATP or NIG application. The co-stimulation with LPS and ATP induced a significant ASC speck formation, caspase-1 activation, cell death and ROS generation. The inhibition of the ATP-dependent purinoreceptor P2X7 decreased the caspase-1 activation, whereas sodium orthovanadate significantly induced caspase-1. Additional treatment with EtOH reversed the LPS and ATP-induced caspase-1 activation, ASC speck formation and ROS production. The ASC speck formation and caspase-1 induction require a two-step signaling with LPS and ATP in HepG2 cells. Inflammasome activation may depend on P2X7. The molecular pathway of an acute effect of EtOH on inflammasomes may involve a reduction in ROS generation, which in turn may increase the activity of tyrosine phosphatases.