Chronic liver diseases are characterized by the expansion of ductular reaction (DR) cells and the expression of liver progenitor cell (LPC) markers. In alcoholic hepatitis (AH), the degree of DR expansion correlates with disease progression and short‐term survival. However, little is known about the biological properties of DR cells, their impact on the pathogenesis of human liver disease, and their contribution to tissue repair. In this study, we have evaluated the transcriptomic profile of DR cells by laser capture microdissection in patients with AH and assessed its association with disease progression. The transcriptome analysis of cytokeratin 7‐positive (KRT7+) DR cells uncovered intrinsic gene pathways expressed in DR and genes associated with alcoholic liver disease progression. Importantly, DR presented a proinflammatory profile with expression of neutrophil recruiting C‐X‐C motif chemokine ligand (CXC) and C‐C motif chemokine ligand chemokines. Moreover, LPC markers correlated with liver expression and circulating levels of inflammatory mediators such as CXCL5. Histologically, DR was associated with neutrophil infiltration at the periportal area. In order to model the DR and to assess its functional role, we generated LPC organoids derived from patients with cirrhosis. Liver organoids mimicked the transcriptomic and proinflammatory profile of DR cells. Conditioned medium from organoids induced neutrophil migration and enhanced cytokine expression in neutrophils. Likewise, neutrophils promoted the proinflammatory profile and the expression of chemokines of liver organoids. Conclusion: Transcriptomic and functional analysis of KRT7+ cells indicate that DR has a proinflammatory profile and promote neutrophil recruitment. These results indicate that DR may be involved in the liver inflammatory response in AH, and suggest that therapeutic strategies targeting DR cells may be useful to mitigate the inflammatory cell recruitment in AH.

EDITORIAL SUMMARY. Human iPSCs are differentiated into hepatic stellate cells by culture with growth factors. They respond to fibrogenic stimuli, arising as a new source of HSC-like cells for in vitro modelling. Subsequent co-culture with hepatocytes facilitates self-assembly into 3D hepatic spheroids.TWEET. Differentiation of human iPSCs to hepatic stellate cell-like cells for in vitro liver modelling.COVER TEASER. Human hepatic stellate cell generation from iPSCs.

Objective: Bacterial infections are common and severe in cirrhosis, but its pathogenesis is poorly understood. Dysfunction of liver macrophages may play a role, but information about their function in cirrhosis is limited. Aims were to investigate the specific profile and function of liver macrophages in cirrhosis and their contribution to infections. Design: Macrophages from human cirrhotic livers were characterized phenotypically by transcriptome analysis and flow cytometry; function was assessed in vivo by SPECT in patients with cirrhosis. Serum levels of specific proteins and expression in peripheral monocytes were determined by ELISA and flow cytometry. In vivo phagocytic activity of liver macrophages was measured by spinning disc intravital microscopy in a mouse model of chronic liver injury.Results: Liver macrophages from patients with cirrhosis overexpressed psroteins related to immune exhaustion such as PD-L1, MARCO and CD163. In vivo phagocytic activity of liver macrophages in patients with cirrhosis was markedly impaired. Monocytes from patients with cirrhosis showed overexpression of PD-L1 that paralleled disease severity, correlated with its serum levels, and was associated with increased risk of infections. Blockade of PD-L1 with anti-PDL1 antibody caused a shift in macrophage phenotype towards a less immunosuppressive profile, restored liver macrophage in vivo phagocytic activity and reduced bacterial dissemination. Conclusion:Liver cirrhosis is characterized by a remarkable impairment of phagocytic function of macrophages associated with an immunosuppressive transcriptome profile. The PD-1/PD-L1 axis plays a major role in the impaired activity of liver macrophages. PD-L1 blockade reverses the immune suppressive profile and increases antimicrobial activity of liver macrophages in cirrhosis.

Background and Aims: Ductular reaction (DR) expands in chronic liver diseases and correlates with disease severity. Besides its potential role in liver regeneration, DR plays a role in the wound-healing response of the liver, promoting periductular fibrosis and inflammatory cell recruitment. However, there is no information regarding its role in intrahepatic angiogenesis. In the current study we investigated the potential contribution of DR cells to hepatic vascular remodeling during chronic liver disease. Approach and Results:In mouse models of liver injury, DR cells express genes involved in angiogenesis. Among angiogenesis-related genes, the expression of Slit2 and its receptor Roundabout 1 (Robo1) was localized in DR cells and neoangiogenic vessels, respectively. The angiogenic role of the

Background and Aims: Alcohol-associated liver disease (ALD) accounts for 70% of liver-related deaths in Europe, with no effective approved therapies. Although mitochondrial dysfunction is one of the earliest manifestations of alcohol-induced injury, restoring mitochondrial activity remains a problematic strategy due to oxidative stress. Here, we identify methylation-controlled J protein (MCJ) as a mediator for ALD progression and hypothesize that targeting MCJ may help in recovering mitochondrial fitness without collateral oxidative damage. Approach and Results: C57BL/6 mice [wild-type (Wt)] Mcj knockout and Mcj liver-specific silencing (MCJ-LSS) underwent the NIAAA dietary protocol (Lieber-DeCarli diet containing 5% (vol/vol) ethanol for 10 days, plus a single binge ethanol feeding at day 11). To evaluate the impact of a restored mitochondrial activity in ALD, the liver, gut, and pancreas were characterized, focusing on lipid metabolism, glucose homeostasis, intestinal permeability, and microbiota composition. MCJ, a protein acting as an endogenous negative regulator of mitochondrial respiration, is downregulated in the early stages of ALD and increases with the severity of the disease. Whole-body deficiency of MCJ is detrimental during ALD because it exacerbates the systemic effects of alcohol abuse through altered intestinal permeability, increased endotoxemia, and dysregulation of pancreatic function, which overall worsens liver injury. On the other hand, liver-specific Mcj silencing prevents main ALD hallmarks, that is, mitochondrial dysfunction, steatosis, inflammation, and oxidative stress, as it restores the NAD+/NADH ratio and SIRT1 function, hence preventing de novo lipogenesis and improving lipid oxidation. Conclusions: Improving mitochondrial respiration by liver-specific Mcj silencing might become a novel therapeutic approach for treating ALD.