Decreased ω6/ω3 PUFA ratio attenuates ethanol-induced alterations in intestinal homeostasis, microbiota and liver injury.

Ethanol (EtOH)-induced alterations in intestinal homeostasis lead to multi-system pathologies, including liver injury. omega-6 PUFAs exert pro-inflammatory activity, while omega-3 PUFAs promote anti-inflammatory activity that is mediated, in part, through specialized pro-resolving mediators [e.g., resolvin D1 (RvD1)]. We tested the hypothesis that a decrease in the omega-6:omega-3 PUFA ratio would attenuate EtOH-mediated alterations in the gut-liver axis. omega-3 FA desaturase-1 (fat-1) mice, which endogenously increase omega-3 PUFA levels, were protected against EtOH-mediated downregulation of intestinal tight junction proteins in organoid cultures and in vivo. EtOH- and lipopolysaccharide-induced expression of INF-gamma, Il-6, and Cxcl1 was attenuated in fat-1 and WT RvD1-treated mice. RNA-seq of ileum tissue revealed upregulation of several genes involved in cell proliferation, stem cell renewal, and antimicrobial defense (including Alpi and Leap2) in fat-1 versus WT mice fed EtOH. fat-1 mice were also resistant to EtOH-mediated downregulation of genes important for xenobiotic/bile acid detoxification. Further, gut microbiome and plasma metabolomics revealed several changes in fat-1 versus WT mice that may contribute to a reduced inflammatory response. Finally, these data correlated with a significant reduction in liver injury. Our study suggests that omega-3 PUFA enrichment or treatment with resolvins can attenuate the disruption in intestinal homeostasis caused by EtOH consumption and systemic inflammation with a concomitant reduction in liver injury.