Binge drinking in obese patients positively correlates with accelerated liver damage and liver-related death. However, the underlying mechanism and the effect of alcohol use on the progression of metabolic-dysfunction-associated steatotic liver disease (MASLD) remain unexplored. Here, we show that short-term feeding of a metabolic-dysfunction-associated steatohepatitis (MASH) diet plus daily acute alcohol binges for three days induce liver injury and activation of the NLRP3 inflammasome. We identify that a MASH diet plus acute alcohol binges promote liver inflammation via increased infiltration of monocyte-derived macrophages, neutrophil recruitment, and NET release in the liver. Our results suggest that both monocyte-derived macrophages and neutrophils are activated via NLRP3, while the administration of MCC950, an NLRP3 inhibitor, dampens these effects.In this study, we reveal important intercellular communication between hepatocytes and neutrophils. We discover that the MASH diet plus alcohol induces IL-1β via NLRP3 activation and that IL-1β acts on hepatocytes and promotes the production of CXCL1 and LCN2. In turn, the increase in these neutrophils recruits chemokines and causes further infiltration and activation of neutrophils in the liver. In vivo administration of the NLRP3 inhibitor, MCC950, improves the early phase of MetALD by preventing liver damage, steatosis, inflammation, and immune cells recruitment.

Background: Cyclic GMP–AMP synthase (cGAS) catalyzes the production of cGAMP, which activates the STING–IRF3 signaling pathway. Previous investigations indicated a role for STING–IRF3 in early alcohol-associated liver disease (ALD). In this study, we examined the role of cGAS in liver damage and inflammation in early ALD. Methods: Wild-type (WT) or cGAS knockout (cGAS-KO) mice received a single dose of alcohol (5 g/kg), and in WT mice with or without a cGAS inhibitor, RU.521 (5 mg/kg) or 2′–3′ cGAMP or control. Liver and serum were evaluated after 9 hours of alcohol administration. Results: Alcohol gavage in cGAS knockout (cGAS-KO) mice led to increased liver damage compared with WT mice. Inhibition of cGAS with the small molecule, RU.521, also resulted in increased serum alanine and aspartate aminotransferases. cGAS deficiency or inhibition made the liver susceptible to alcohol-induced apoptosis. Alcohol-fed cGAS-KO mice and WT mice treated with the cGAS inhibitor showed enhanced unfolded protein response in the liver. This was associated with elevated levels of the proinflammatory cytokines, macrophage migration inhibitory factor, CD68 ⁺ cells, Ly6G ⁺ cells, and chemokines like lipocalin-2 and neutrophil elastase. Primary hepatocytes isolated from cGAS-KO mice displayed increased levels of cleaved caspase-3, XBP1s, and CHOP after alcohol administration as compared with WT control hepatocytes. Interestingly, restoration of cGAMP levels after cGAS inhibition improved liver damage and autophagic flux. Conclusions: Our findings highlight that cGAS deficiency or cGAS inhibition predisposes the liver to increased damage, apoptosis, and unfolded protein response in early ALD. An increase in the proinflammatory cytokine MIF and chemokines involved in neutrophil recruitment might contribute to the increased liver damage. In summary, our findings indicate a protective role for cGAS activation in early ALD.