1 MCP-1 plays an important Ibrutinib molecular weight role in the induction of proinflammatory cytokines at the site of tissue injury.10 Here, we investigated

the effect of MCP-1 deficiency on alcohol-induced expression of cytokines in the liver. We elucidated the expression of circulating endotoxin (baseline)-mediated induction of proinflammatory cytokines TNFα, IL-1β, and IL-6, as well as CC-chemokine mRNA levels in liver of alcohol-fed WT and MCP-1KO mice. Here, we show that TNFα, IL-1β, and IL-6 mRNA was increased significantly in alcohol-fed WT mice, compared to pair-fed WT controls, whereas alcohol-fed MCP-1KO mice were unable to induce proinflammatory cytokine mRNA in the liver (Fig. 3A). MCP-1 deficiency also prevented chronic alcohol-induced liver tissue TNFα, as compared to WT mice (Fig. 3B). Interestingly, among CC-chemokine genes, KC/IL-8 INCB024360 in vivo mRNA was significantly decreased, but CCL4/MIP-1β and CCL5/RANTES mRNA was high in alcohol-fed MCP-1KO mice, compared to pair-fed controls (Fig. 3C). Furthermore, investigation of MCP-1-mediated adhesion molecules and macrophage markers demonstrated a significant induction of intercellular adhesion molecule 1 (ICAM-1) and cluster of differentiation (CD)68, but unchanged vascular cell adhesion molecule 1 (VCAM-1) and F4/80 in livers of alcohol-fed WT, but not MCP-1KO, mice (Fig. 3D). Because nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) is important in chronic alcohol-mediated proinflammatory

cytokine production and macrophage activation,15 we next determined whether the inhibition of inflammatory cytokines was regulated by the lack of NF-κB activation in MCP-1-deficient mice. Interestingly, our results show that NF-κB binding activity in whole livers was significantly increased in alcohol-fed MCP-1-deficient mice (Fig. 3E), compared to alcohol-fed WT and pair-fed MCP-1KO mice. Furthermore, increased NF-κB activation

was observed in isolated KCs of alcohol-fed MCP-1KO and WT mice, compared to pair-fed controls (Fig. 3F). Immunohistochemical analysis revealed Metalloexopeptidase NF-κB p65 staining in nonparenchymal cells of alcohol-fed WT and MCP-1KO mice (Supporting Fig. 3). On the other hand, isolated hepatocytes showed decreased NF-κB activation in alcohol-fed WT mice, compared to pair-fed controls, and this inhibition was prevented in alcohol-fed MCP-1KO mice (Fig. 3F), likely contributing to NF-κB-mediated hepatocyte survival in alcohol-fed MCP-1KO mice. These results indicate that liver proinflammatory cytokine mRNA, ICAM-1, and CD68 are significantly decreased in chronic alcohol-fed MCP-1KO mice, compared to their WT counterparts, in an NFκB-independent manner. The classical feature of alcoholic liver injury is alcohol-mediated oxidative stress and increased sensitization to LPS, resulting in enhanced proinflammatory cytokine expression in the liver.1, 16 To further test the effect of sensitization to LPS in chronic alcohol-fed MCP-1-deficient mice, an in vivo LPS challenge (0.