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In the context of gut leakiness and translocation of microbial products in alcohol-associated liver disease (ALD), it is possible that systemic and liver inflammation involve the activation of circulating monocyte through gut-derived factors. We explored the association between monocytes, microbial translocation, systemic inflammation, and ALD. Patients with alcohol use disorder following a rehabilitation program were compared with healthy controls. We determined the circulating number and proportion of monocyte subsets by FACS. The activation of signaling pathways by gut-derived microbes was analyzed by quantitative PCR in isolated monocytes. Cytokines secretion by monocytes and phagocytosis were assessed in vitro. Serum microbial translocation markers and cytokines were measured by ELISA and multiplex assay, respectively. ALD severity and liver inflammatory responses were analyzed in liver biopsies by various methods. In patients with alcohol use disorder, the number of blood monocytes increased compared with controls. Monocytes from patients with alcohol use disorder upregulated IL-1β and IL-8 together with toll-like receptor 2 and downstream AP-1, while fungal sensor CARD9 was downregulated. IL-1β and IL-8 were actively secreted upon stimulation in vitro with the toll-like receptor 2 ligand peptidoglycan. Exposure with Escherichia coli confirmed preserved bacterial phagocytic activity. In contrast, Candida albicans stimulation leads to downregulation of IL-1β and TNFα compared with controls. Systemic cytokines and monocyte changes correlated with microbial translocation. Hepatic IL-1β and IL-8 increased with ALD severity together with liver macrophage activation and upregulation of chemokines involved in monocyte attraction. Our results point to the contribution of activated monocytes to systemic inflammation and ALD. Monocytes likely infiltrate the liver, transform into monocyte-derived macrophages and release IL-1β and IL-8 in response to peptidoglycan and toll-like receptor 2 activation.

High levels of extracellular adenosine, often found in the tumor microenvironment (TME), promote immune suppression mainly through the A2A receptor (A2AR) expressed by tumor-infiltrating immune cells. Inupadenant (formerly known as EOS100850) is an oral, non-brain penetrant, potent and highly selective small molecule antagonist of A2AR. In a Phase I/Ib clinical trial (NCT02740985), inupadenant as monotherapy showed initial evidence of clinical benefit in subjects with advanced solid tumors. In this study, tumor biopsies with a high number of A2AR-expressing immune cells at baseline were associated with response or stable disease.We now report that infiltration of A2AR+ cells was strongly correlated with the expression of B- and, more specifically, antibody-secreting cell (ASC)-related genes, as assessed by gene expression (Nanostring) and immunohistochemistry (IHC), hinting at a potential novel role for A2AR in B cell biology. Therefore, we explored the expression and function of A2AR in human B cells. Immunocytochemistry staining of A2AR on sorted tonsillar B cell subsets showed that A2AR was predominantly expressed on ASCs, including plasma cells and plasma blasts versus naïve or memory B cells. The preferential expression of A2AR by ASCs was confirmed on NSCLC tissues by multiplex immunofluorescence. In addition to A2AR, ASCs expressed other adenosine pathway markers such as CD39, suggesting that the adenosine pathway is a key mechanism through which ASC functions may be modulated. Using B cells derived from peripheral blood, the A2AR agonist CGS-21680 was shown to inhibit the maturation of B cells into plasma cells, and that maturation could be fully restored by inupadenant. CGS-21680 did not affect B cell or plasma cell viability, indicating that the effect of A2AR signaling on plasma cell differentiation is not due to preferential plasma cell death in culture. Importantly, baseline expression of B cell- and ASC-related markers measured by Nanostring and IHC was associated with response or stable disease to inupadenant monotherapy, supporting the notion that these cells may be a novel target of inupadenant. This is in line with recent reports showing that B cells, plasma cells and tertiary lymphoid structures are associated with favorable responses to cancer immunotherapy. Interestingly, four out of the five non-progressors treated with inupadenant as monotherapy and with available biomarker data showed a reduction in ASC infiltration after inupadenant treatment, suggesting that inupadenant may promote terminal plasma cell differentiation and migration out of the tumor tissue and to the bone marrow.Altogether, these data support a novel plasma cell-centric mechanism of action of inupadenant, which may complement its reported T cell-mediated anti-tumor activity. Citation Format: Chiara Martinoli, Paola Tieppo, Marjorie Mercier, Hussein Shehade, Noemie Wald, Anais Vezzu, Annelise Hermant, Boris Pirlot, Stephanie Ma, Maurizio Ceppi, Yvonne McGrath, Maura Rossetti. A novel plasma cell-based mechanism of action of adenosine immunomodulation and A2AR antagonism. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4135.

Portal hyperperfusion and "dearterialization" of the liver remnant are the main pathogenic mechanisms for Small For Size syndrome (SFSS). Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) induces rapid remnant hypertrophy. We hypothesized a similar increase in portal pressure/flow into the future liver remnant in ALPPS and SFSS-setting hepatectomies. In a rodent model, ALPPS was compared to SFSS-setting hepatectomy. We assessed mortality, remnant hypertrophy, hepatocyte proliferation, portal and hepatic artery flow, hypoxia-induced response, and liver sinusoidal morphology. SFSS-hepatectomy rats were subjected to local (hepatic artery ligation) or systemic (Dimethyloxalylglycine) hypoxia. ALLPS prevented mortality in SFSS-setting hepatectomies. Portal hyperperfusion per liver mass was similar in ALLPS and SFSS. Compared to SFSS, efficient arterial perfusion of the remnant was significantly lower in ALPPS causing pronounced hypoxia confirmed by pimonidazole immunostaining, activation of hypoxia sensors and upregulation of neo-angiogenic genes. Liver sinusoids, larger in ALPPS, collapsed in SFSS. Induction of hypoxia in SFSS reduced mortality. Hypoxia had no impact on hepatocyte proliferation but contributed to the integrity of sinusoidal morphology. ALPPS hemodynamically differ from SFSS by a much lower arterial flow in ALPPS's FLR. We show that the ensuing hypoxic response is essential for the function of the regenerating liver by preserving sinusoidal morphology.

ObjectivePancreatic cancer can arise from precursor lesions called intraductal papillary mucinous neoplasms (IPMN), which are characterised by cysts containing papillae and mucus-producing cells. The high frequency of KRAS mutations in IPMN and histological analyses suggest that oncogenic KRAS drives IPMN development from pancreatic duct cells. However, induction of Kras mutation in ductal cells is not sufficient to generate IPMN, and formal proof of a ductal origin of IPMN is still missing. Here we explore whether combining oncogenic KrasG12D mutation with an additional gene mutation known to occur in human IPMN can induce IPMN from pancreatic duct cells.DesignWe created and phenotyped mouse models in which mutations in Kras and in the tumour suppressor gene liver kinase B1 (Lkb1/Stk11) are conditionally induced in pancreatic ducts using Cre-mediated gene recombination. We also tested the effect of β-catenin inhibition during formation of the lesions.ResultsActivating KrasG12D mutation and Lkb1 inactivation synergised to induce IPMN, mainly of gastric type and with malignant potential. The mouse lesions shared several features with human IPMN. Time course analysis suggested that IPMN developed from intraductal papillae and glandular neoplasms, which both derived from the epithelium lining large pancreatic ducts. β-catenin was required for the development of glandular neoplasms and subsequent development of the mucinous cells in IPMN. Instead, the lack of β-catenin did not impede formation of intraductal papillae and their progression to papillary lesions in IPMN.ConclusionOur work demonstrates that IPMN can result from synergy between KrasG12D mutation and inactivation of a tumour suppressor gene. The ductal epithelium can give rise to glandular neoplasms and papillary lesions, which probably both contribute to IPMN formation.

Background Animal data suggest a role of the gut-liver axis in progression of alcoholic liver disease (ALD), but human data are scarce especially for early disease stages. Methods We included patients with alcohol use disorder (AUD) who follow a rehabilitation program and matched healthy controls. We determined intestinal epithelial and vascular permeability (IP) (using urinary excretion of 51Cr-EDTA, fecal albumin content, and immunohistochemistry in distal duodenal biopsies), epithelial damage (histology, serum iFABP, and intestinal gene expression), and microbial translocation (Gram – and Gram + serum markers by ELISA). Duodenal mucosa-associated microbiota and fecal microbiota were analyzed by 16 S rRNA sequencing. ALD was staged by Fibroscan® (liver stiffness, controlled attenuation parameter) in combination with serum AST, ALT, and CK18-M65. Results Only a subset of AUD patients had increased 51Cr-EDTA and fecal albumin together with disrupted tight junctions and vasculature expression of plasmalemma Vesicle-Associated Protein-1. The so-defined increased intestinal permeability was not related to changes of the duodenal microbiota or alterations of the intestinal epithelium but associated with compositional changes of the fecal microbiota. Leaky gut alone did not explain increased microbial translocation in AUD patients. By contrast, duodenal dysbiosis with a dominance shift toward specific potential pathogenic bacteria genera (Streptococcus, Shuttleworthia, Rothia), increased IP and elevated markers of microbial translocation characterized AUD patients with progressive ALD (steato-hepatitis, steato-fibrosis). Conclusion Progressive ALD already at early disease stages is associated with duodenal mucosa-associated dysbiosis and elevated microbial translocation. Surprisingly, such modifications were not linked with increased IP. Rather, increased IP appears related to fecal microbiota dysbiosis.