Journal of Hepatology

Background & Aims: Immune-mediated liver injury from immune checkpoint inhibitors (ILICI) is a major immune-related adverse event that limits cancer immunotherapy, yet its tissue-level immunobiology is poorly defined and its management is largely extrapolated from autoimmune hepatitis (AIH). We previously identified a tri-cellular CD8+ T cell-macrophage-hepatocyte injury niche in a murine model of ILICI; here, we tested whether this niche is recapitulated in human disease. Methods: We applied imaging mass cytometry with a 32-marker panel to liver biopsies from patients with ILICI (n = 12), AIH as a disease comparator (n = 14), and healthy controls (n = 2), profiling approximately 297,000 single cells across 144 regions of interest with spatially resolved detection of apoptosis (cleaved caspase-3, cC3) and pyroptosis (cleaved gasdermin D, cGSDMD). Results: We detected histiocyte-rich granulomas in ILICI consisting of macrophages and CD8+ T cells, including activated memory-effector subsets. Permutation-based spatial analysis identified CD8+ T cell-macrophage co-localization as the most frequent significant interaction in ILICI, organizing into integrated innate-adaptive cellular neighborhoods that concentrated cC3- and cGSDMD-positive cells. Descriptively, this contrasted with AIH, in which immune cells and stroma were more spatially compartmentalized. CD8+ T-cell and macrophage densities correlated with Ishak necroinflammation scores, jaundice, and granuloma formation. Conclusions: These findings provide the first single-cell spatial proteomic characterization of human ILICI in situ; they recapitulate the tri-cellular CD8-macrophage-hepatocyte niche we previously defined in a murine model and characterize ILICI as a spatially organized innate-adaptive inflammatory process, nominating myeloid signaling and CD8-macrophage interactions as candidate liver-directed targets to uncouple hepatotoxicity from anti-tumor immunity.

Nuclear bile acid (BA) signaling plays a central role in liver homeostasis and represents a major therapeutic axis in fibrotic liver diseases. The farnesoid X receptor (FXR), a master nuclear effector of BA signaling, is expressed in several liver-resident cell types, suggesting that it may regulate distinct biological programs beyond the hepatocyte (HC) compartment. Using complementary pharmacological, genetic, and computational approaches across in vitro, ex vivo, and in vivo models of mouse and human origin, we investigated the role of hepatic stellate cell (HSC) FXR (FXRHSC) in both unchallenged and injured livers, which has remained controversial. FXR is robustly expressed in both HCs and HSCs with distinct isoform distributions, and these isoforms exhibited differential capacities to activate gene expression in an HSC context. We found that the potent selective FXR agonist tropifexor triggers a transcriptional program reminiscent of that observed after partial hepatectomy and associated with HC proliferation. This cell cycle-related response was also observed in HSCs and did not require intestinal FXR expression. An HSC-specific response to tropifexor was observed for several genes, including members of the glutathione-S-transferase (GST) family or Scube1. FXRHSC was sufficient to observe the anti-fibrotic effects of tropifexor in precision-cut liver slices, an ex-vivo model of fibrosis. Finally, we identified the regulation of the chemerin-encoding gene Rarres2 as a relevant example of FXRHSC-dependent control of hepatic intercellular communication. Together, these findings identify FXRHSC as an important contributor to hepatic adaptation and therapeutic response to BA analogs and confirmed HSCs as a significant site of nuclear bile acid signaling in liver biology.

Reliance on invasive liver biopsy endpoints is a major limiting factor in new therapeutic development for metabolic dysfunction-associated steatohepatitis (MASH). While liver fat accumulation is considered a driver of early disease, liver fat reduction is not recognized as a surrogate endpoint by health authorities. Here, we conducted the largest-to-date genome-wide association study (GWAS) of liver fat in 79,642 people with magnetic resonance imaging and developed a polygenic score with liver fat-lowering alleles across 55 genomic loci. In a separate set of 714,886 individuals, a 30% relative liver fat reduction due to the polygenic score was associated with 39% lower odds of liver cirrhosis and 41% lower odds of hepatocellular carcinoma, consistent with a strong causal relationship between lifelong liver fat differences and advanced liver clinical outcomes. A systematic review and meta-analysis of 20 randomized controlled trials including a total of 3,502 MASH patients showed that treatment-induced liver fat reductions were associated with MASH resolution (meta-regression slope in % units of the outcome for each 1% relative reduction in liver fat from baseline, {beta} = -0.70%, p<0.001) and fibrosis improvement ({beta} = -0.24%, p<0.001). These findings demonstrate the profound etiologic impact of liver fat in MASH and provide compelling evidence for liver fat reductions as a reasonably likely surrogate endpoint for future clinical development.

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality, yet its pathogenesis remains incompletely understood. While neural regulation is critical for hepatic homeostasis, how autonomic and neurotrophic signaling is regulated in the liver during ALD progression remains largely unexplored. Here, we performed an integrative analysis of bulk and single-cell transcriptomic datasets of human livers across the spectrum of ALD. We identified stage-dependent remodeling and coordinated expression patterns of autonomic and neurotrophic genes. Autonomic signaling exhibited a consistent decline, with reduced expression of sympathetic (DBH, TH) and the parasympathetic (ChAT) markers. In contrast, pan-neuronal and neuroplasticity-associated genes (UCHL1, TUBB3, STMN2) were upregulated, indicating active neural remodeling. In parallel, factors such as MANF, GDNF, and NRG2, with the receptor NTRK1, were upregulated and positively correlated with clinical indicators of disease severity, inflammation and fibrosis. In contrast, trophic factors including NTF3 and CDNF, and receptors such as GFRA1 and GFRA3, were downregulated and inversely associated with these parameters. Single-cell analyses revealed that neurotrophic factors are predominantly expressed by hepatic stellate cells, supporting their role as resident neuroglia-like cells in the liver. In another independent cohort, we observed a coordinated downregulation of NTF3 and sympathetic nerve markers in alcohol-associated hepatitis (AH), suggesting impaired NTF3-mediated neurotrophic support may contribute to sympathetic dysfunction in AH. Collectively, these findings uncover previously unrecognized neuro-regulatory dimensions in ALD and suggest that dysregulated autonomic and neurotrophic signaling may contribute to disease progression. Conflict of interestThe authors have declared that no conflict of interest exists.

Background: Hepatitis B virus (HBV) basal core promoter (BCP) and precore (PC) mutations occur during chronic HBV infection with the BCP-mutant being associated with increased hepatocellular carcinoma (HCC) risk. Objectives: The effects of these mutants on viral replication, hepatocyte biology, and carcinogenesis remain poorly defined. To address this, we characterized BCP- and PC-mutants using human hepatocyte chimeric mice and asked whether the resulting infection-induced transcriptomes correspond to subsets of human HBV-related hepatocellular carcinomas (HBV-HCCs). Design: Isogenic wild-type (WT), BCP- and PC-mutants of HBV genotypes A, C, and D (HBV-A, -C, -D) were generated from recombinant covalently-closed circular DNA to infect chimeric mice. HBV-HCC transcriptomic datasets from The Cancer Genome Atlas (TCGA) were used to stratify association of HBV variants with HCC subtypes. Results: WT, BCP-mutant, and PC-mutant HBV sequences remained genetically stable. The BCP mutation, but not the PC mutation, accelerated the rise in serum viremia in HBV-D- and HBV-A-infected chimeras; in HBV-C, acceleration required both (PC+BCP) mutations. Further comparisons of HBV-D variants revealed that the BCP-mutant increased intrahepatic viral DNA, viral protein expression, and upregulated cancer-related pathways, including transcripts associated with a subset of HBV-HCCs. Analysis of HBV-HCC samples from the TCGA revealed that tumors often harbor a mixture of WT and mutant transcripts, and that WT- and BCP-mutant-associated HCCs exhibit distinct transcriptional profiles. Conclusions: The HBV BCP-mutant directly perturbs hepatocyte homeostasis via virus-intrinsic mechanisms, selectively activating cancer-related pathways and defining a molecularly distinct subset of HBV-HCC. These findings suggest that HBV variants form distinct subcategories of HBV-HCCs.

Background: The gut-liver axis is involved in Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD), but the host molecular actors involved in such dialogue have not yet been fully characterized. Objective: We investigated the sex-dependent role of the Constitutive Androstane Receptor (CAR) as a hepatic sensor of microbial signals in MASLD pathophysiology. Design: Male and female Car+/+ and Car-/- mice were fed a western diet (WD) for 4, 14 or 35 weeks. We performed plasma biochemistry, liver histology, bile acid and cholesterol quantification, untargeted multi-omics approach combining liver RNA-sequencing and 16S rRNA sequencing, together with co-housing, fecal microbiota transplantation and analysis of publicly available transcriptomics data in human cohorts. Results: Short-term WD revealed CAR-dependent protection against steatosis, together with perturbations in the transcriptional signatures of multiple transcription factors involved in hepatocyte identity in males. After 14 weeks, CAR deletion increased WD-induced liver damage, inflammation and fibrosis, and disrupted bile acid, cholesterol and gut microbiota homeostasis, in males only. Co-housing and fecal microbiota transplantations revealed that a Car+/+ gut microbiota protected against WD-induced liver damage, while a Car-/- microbiota was reshaped by a Car+/+ host. No CAR-dependent phenotype was observed in females. Finally, in human cohorts, hepatic CAR expression decreased in advanced clinical stages of MASLD. Conclusion: CAR is a sex-dependent protective nuclear receptor against MASLD progression, acting both as a transcriptional regulator of hepatocyte identity and as a mediator of the host-microbiota crosstalk.

Background & aimsChronic inflammation is a key driver of progression from benign steatosis to metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis. The molecular mechanisms coupling inflammatory cytokine signaling to altered hepatocyte remodeling remain incompletely understood. Here, we report that nicotinamide N-methyltransferase (NNMT) is induced by specific inflammatory cytokines in hepatocytes and acts as a key hub to connect inflammation with fibrotic liver remodeling. Approach & resultsTranscriptomic profiling of primary human hepatocytes and human hepatoma cell lines identified NNMT as a selective downstream target of IL-1{beta} and IL-6, but not of TNF. Genetic silencing of NNMT markedly attenuated cytokine-induced inflammatory and fibrotic gene expression programs and partially reversed IL-6-mediated sensitization of IL-1{beta} responses. Integration of RNA-seq with ChIP-seq, CUT&Tag, and ATAC-seq revealed that inflammatory cytokines remodel the hepatocyte epigenome through coordinated changes in histone modifications. NNMT overexpression promoted selective remodeling of H3K4me2 chromatin landscapes, accompanied by activation of fibrosis-associated transcriptional programs. Nicotinamide supplementation partially suppressed inflammatory gene expression, supporting a role of NNMT-dependent NAD+ metabolism in this process. Importantly, cytokine-induced NNMT expression and its associated transcriptional program were conserved in primary human hepatocytes and 3D liver microtissues. ConclusionsNNMT functions as an inflammatory cytokine-inducible metabolic- epigenetic integrator that links IL-1{beta} and IL-6 signaling to chromatin remodeling and inflammatory transcriptional reprogramming in hepatocytes. These findings identify NNMT as a key regulator of inflammatory and profibrotic responses during MASLD progression and highlight NNMT as a potential therapeutic target for limiting liver inflammation and fibrosis. Impact and ImplicationsThis study identifies NNMT as a previously unrecognized metabolic-epigenetic integrator that selectively links IL-1{beta} and IL-6 signaling to chromatin remodeling and inflammatory transcriptional reprogramming in hepatocytes. Our findings establish a non-canonical mechanistic framework by which inflammatory cytokines drive profibrotic gene expression during MASLD progression through. By uncovering NNMT as a critical mediator of inflammatory-epigenetic crosstalk, this work broadens our understanding of hepatocyte-intrinsic mechanisms underlying liver fibrosis and highlights NNMT as a promising therapeutic target for preventing the transition from steatosis to progressive MASH and fibrosis. HighlightsO_LINNMT is selectively induced by IL-1{beta} and IL-6 in hepatocytes. C_LIO_LINNMT controls fibrogenic gene expression modules. C_LIO_LIIL-6 amplifies IL-1{beta} responses through an NNMT-dependent mechanism. C_LIO_LINNMT links inflammatory signaling to epigenetic remodeling in MASLD. C_LI

Background & Aims: Metabolic dysfunction-associated steatohepatitis (MASH) is a leading cause of chronic liver disease, and liver fibrosis is the principal determinant of disease progression and clinical outcome. We recently showed that non-apoptotic caspase-8 in hepatocytes is upregulated in MASH and leads to the induction and secretion of meteorin, which promotes hepatic stellate cell (HSC) activation and liver fibrosis. We address here the major mechanistic question arising from this study, namely how non-apoptotic caspase-8 induces pro-fibrotic meteorin in hepatocytes in MASH. Methods: Mechanistic studies were performed using AML12 hepatocytes; primary mouse and human hepatocytes; and diet-induced mouse models of MASH with hepatocyte-specific caspase-8 deletion. YY1 post-translational modifications were identified by LC-MS/MS and investigated using phosphorylation-defective and phosphomimetic YY1 mutants. Genetic and biochemical approaches were used to interrogate the caspase-8 DED-SRC-GSK3b; pathway, and its relevance was assessed in human MASH liver specimens. Results: In vitro mechanistic studies showed that the amino-terminal death effector domain (DED) of caspase-8 activated a SRC-GSK3b signaling cascade that promoted phosphorylation of YY1 at Ser247, resulting in YY1 nuclear localization and Metrn induction. Disruption of the conserved DED RXDLL motif impaired SRC activation, YY1 phosphorylation, and Metrn expression. Hepatocyte YY1 overexpression increased Metrn expression and fibrosis in wild-type MASH mice but not in hepatocyte-caspase-8-deficient mice. In contrast, phosphomimetic YY1-S247D restored these endpoints even when hepatocyte caspase-8 was lacking. Studies in primary mouse and human hepatocytes and human MASH liver specimens supported conservation of this signaling pathway. Conclusions: These findings identify YY1 Ser247 phosphorylation as a critical molecular event linking non-apoptotic hepatocyte caspase-8 signaling to METRN induction and MASH fibrosis and define a previously unrecognized DED-SRC-GSK3b-YY1 signaling axis with potential therapeutic relevance.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a common, clinically heterogeneous condition associated with liver-related and cardiometabolic morbidity. Sex differences in MASLD prevalence and progression are well recognized, but how they extend across the liver and visceral adipose tissue (VAT), a major source of lipid and endocrine signals to the liver, remains unclear. Here, we profiled paired liver and VAT biopsies from women and men with and without MASLD, generating single-nucleus datasets of 34 liver samples and 40 VAT samples, including 32 patient-matched pairs. In liver, women with MASLD showed a higher Kupffer-cell triglyceride-catabolism score (1.30-SD female-male difference; FDR=0.0022), accompanied by directionally consistent hepatocyte and endothelial programs. In VAT, women with MASLD showed higher adipocyte lipid and oxidative metabolism (0.87-1.15 SD; FDR<0.05 across seven pathways) together with macrophage immune activation, whereas men with MASLD showed stronger stromal communication routes. Across matched patients, gene modules linked VAT adipocyte and macrophage states to liver hepatocyte stress and lipid-receipt states. Bulk RNA-seq module scoring and paired liver-VAT analyses in 293 patients supported hepatic stress in both sexes, lower adipocyte signaling in women with increasing steatosis, and cross-tissue adipocyte-hepatocyte coupling (r=0.30; FDR=2.1e-6). Together, these findings identify distinct sex-associated transcriptional states in liver and VAT in MASLD and show that these states are coordinated across both tissues within the same individuals.

Hospital readmission is used in cirrhosis research as if a return to hospital meant the disease had worsened: it is a trial outcome, a quality indicator and a prediction target. We asked what those readmissions were. Sixty-one adults with alcohol-related cirrhosis, selected because they had been hospitalized more than once, contributed all 326 later admissions to one department. A clinician read each full record and classified it for acute decompensation and for admission mode, blinded to diagnostic codes and structured flags. Fewer than two in five admissions (125, 38.3%) were decompensations. One in three (114) had been booked in advance; none of these was a decompensation, yet they used 29.1% of all bed-days. Among 124 returns within 30 days, planned admissions outnumbered decompensations, 48 to 43. Counting all admissions tracked a patients decompensations only moderately (correlation 0.50) whereas counting urgent admissions tracked them closely (0.93). In crude analysis the sicker patients had fewer admissions, not more, because planned care goes to those well enough to receive it. A liver severity score, computable for 165 admissions, did not separate planned from urgent admissions or decompensations from other stays, even within one patient. Readmission was not the same thing as decompensation.

Background & aims: TP53 (p53) coordinates diverse cellular stress response programmes including pro-survival activities, senescence, and cell death. During tissue damage, p53 can shape both the local cellular response to injury, including the fibrotic response, and influence distal organ biology. Fibrosis in the liver is a major driver of hepatocellular carcinoma (HCC) risk within metabolic dysfunction-associated steatohepatitis (MASH). It is also an important determinant of dysfunction in multiple distal tissues including the kidneys, lungs, and heart. Despite significant clinical burden, our understanding of the molecular determinants of fibrotic MASH and its relationship to multiorgan fibrosis remain incomplete. Here, we investigate local and systemic effects of hepatocellular p53 activity and cholesterol during MASH development, with implications for disease prevention. Methods: This study utilised a genetic model of stabilised p53, diet-induced MASH models with varying cholesterol compositions, and an in vitro obesogenic system to investigate p53 activity during liver disease development. Non-invasive imaging and histopathological analyses were employed to monitor p53 activity, MASH, and multiorgan fibrosis in vivo. Complementary approaches, including in vitro human multicomponent liver spheroids, cytokine arrays, and analyses of human MASH transcriptomic and proteomic datasets, were used to examine molecular drivers and patient relevance. Results: Using an inducible mouse model of MDM2 E3 ubiquitin ligase deficiency to stabilise p53, we report that hepatocellular MDM2 E3 loss results in progressive fibrotic damage, robust hepatocellular expression of the p53 target gene CDKN1A/p21 (p21),and induces p21 and fibrosis in the kidneys of male mice in a sex-specific manner. In diet-induced MASH, we observe cholesterol and p53-dependent development of liver fibrosis, high expression of hepatocellular p21, and induction of p21 and fibrosis in the kidneys of male mice-reminiscent of features observed in MDM2 E3-deficient mice. We also observe fibrosis in the lungs and heart of male MASH mice. Both a cholesterol-free obesogenic diet and liver-specific loss of p53 mitigate hepatic fibrosis and systemic induction of p21 and fibrosis. Mechanistically, p53 induces hepatic expression of senescence-associated secretory phenotype (SASP) factors, including GDF15, in vivo. A human multicomponent LiverACE spheroid model showed a concordant trend towards increased GDF15 protein abundance under steatotic stress, while in humans, elevated circulating GDF15 levels in advanced MASH correlate with increased TNFRSF1A and EPHA2, circulating markers linked to kidney injury. Conclusions: Our work identifies undue p53 activity within the liver as a driver of multiorgan fibrosis in a sex-specific manner, affecting male but not female mice. We implicate cholesterol in promoting this pro-fibrotic environment in vivo and highlight circulating factors that could identify at-risk patients for multiorgan fibrosis in MASH.

Neutrophils infiltrate the liver as metabolic dysfunction-associated steatotic liver disease (MASLD) progresses from simple steatosis to steatohepatitis, but whether neutrophil effectors merely mark this transition or cause it is unknown. Here we show that human neutrophil peptides (HNPs), or alpha-defensins, are drivers rather than bystanders of disease. In patients surgically treated for hepatic hemangioma who displayed overt MASLD, the abundance of HNPs in their liver biopsy samples localized to diseased tissue correlates with the histological severity of steatosis. In vitro, HNPs enter hepatocytes to induce multimerization of voltage-dependent anion channel 1 (VDAC1) in the mitochondrial outer membrane, causing mitochondrial dysfunction and lipid accumulation. Under lipid overload, but not on a standard diet, HNP1-transgenic mice develop increased adiposity and steatohepatitis, which is reversed by an orally available prodrug that inhibits HNP-induced VDAC1 multimerization. These findings link neutrophil innate immunity to hepatocyte mitochondrial dysfunction, recast host-protective HNPs as pathogenic effectors when hepatocyte mitochondria are lipid-burdened, and establish the HNP-VDAC1 axis as a therapeutic target in MASLD.

Metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) arise, in part, from excessive free fatty acid flux from adipose tissue to the liver. Activin E (ActE, encoded by INHBE) suppresses adipocyte lipolysis through the type I receptor ALK7 (ACVR1C). Loss-of-function variants in INHBE and ACVR1C reduce waist-to-hip ratio in humans, yet genetic knockouts in mice produce insulin resistance and hepatic steatosis, suggesting discrepancies between human and mouse biology. We identify GDF3, a TGF-{beta} superfamily ligand upregulated in obese adipose tissue, as the principal endogenous antagonist of ActE/ALK7 signaling. Human transcriptomic datasets reveal coordinated dysregulation: hepatic INHBE expression and circulating ActE protein are elevated in obesity, while adipose ACVR1C is downregulated and GDF3 is reciprocally upregulated. Using ALK7-selective reporter assays, we show GDF3 inhibits ActE-driven SMAD2/3 signaling as a competitive antagonist rather than the weak agonist previously proposed. ActE suppressed beta-adrenergic-stimulated lipolysis in mouse and human adipocytes and primary human adipose tissue; GDF3 overexpression abolished this effect. In diet-induced obese mice, inducible Gdf3 deletion reduced adipose lipolysis, resolved hepatic steatosis and fibrosis, and improved insulin sensitivity, benefits abolished by Inhbe knockdown, confirming dependence on ActE signaling. Predicted loss-of-function variants in INHBE show only nominal, WHR-dependent associations with type 2 diabetes risk, potentially confounded by hematological effects on HbA1c. Gdf3 deficiency synergized with the clinical-stage anti-activin receptor antibody Bimagrumab to amplify fat-mass loss and improve glucose homeostasis in multiple MASH models. These findings establish GDF3 as an endogenous antagonist of ActE-ALK7 signaling and nominate GDF3 inhibition as a therapeutic strategy for MASLD/MASH.

Hepatic fibrosis remains a major cause of morbidity and mortality in patients with schistosomiasis without effective therapy. Here we show that vitamin D receptor (VDR) signaling in macrophages is essential for limiting fibrosis, acting through a previously unrecognized metabolic epigenetic circuit. Hepatic macrophages exhibit the highest VDR expression among liver resident cells, and pharmacological VDR activation with paricalcitol selectively expands a protective SPP1+ macrophage subset derived from circulating monocytes. Myeloid specific VDR knockout exacerbates fibrosis and abrogates paricalcitol's hepatoprotective effects, whereas SPP1+ macrophage depletion worsens disease. Mechanistically, VDR activation synergizes with hypoxia and lactate to drive SPP1 expression via glycolytic reprogramming. Moreover, lactate and HIF1alpha cooperatively induce VDR transcription by binding to the Vdr promoter and enhancing histone lactylation, forming a positive feedback loop that amplifies the antifibrotic response. Our findings establish the lactate-HIF1alpha-VDR-SPP1 axis as an endogenous defense mechanism and identify macrophage VDR as a promising therapeutic target for fibrotic liver diseases.

Objective: Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) frequently present as overlap syndromes, characterized by shared sexual dimorphism and elevated intestinal Veillonella dispar (V. dispar) abundance, yet exhibiting distinct hallmark pathological manifestations. This study aimed to elucidate the shared pathogenesis, phenotypic differentiation mechanisms and sex-specific predisposition of AIH and PBC induced by V. dispar. Methods: Clean-grade and germ-free (GF) mice were employed to establish AIH and PBC models. Model induction involved oral gavage of V. dispar and intraperitoneal injection of either liver-specific antigen S100 (for AIH) or a pyruvate dehydrogenase complex E2 subunit (PDC-E2) mimetic peptide (for PBC). Single-cell RNA sequencing, metabolomics, transmission electron microscopy, western blotting, and flow cytometry were utilized to elucidate the underlying mechanisms. Results: V. dispar successfully induced autoimmune liver disease-like features in mice, characterized by significant intrahepatic B cell infiltration. Mechanistically, V. dispar caused systemic arginine reduction, leading to intrinsic apoptosis of gonadal stromal cells and a subsequent reduction in testosterone. This decreased testosterone weakened its inhibitory effect on B cell activating factor (BAFF) secretion, thereby amplifying B cell-mediated immune responses. Furthermore, in the presence of S100 or PDC-E2 mimetic peptide, V. dispar also facilitated Th17 cell activation, which guided the phenotypic differentiation into AIH or PBC, respectively. Consistent with these findings, our clinical observations revealed that patients with AIH and PBC tended to harbor enriched V. dispar, along with lower serum arginine and testosterone. In addition, elevated serum levels of BAFF and IL-17 were also observed in these patients. Conclusion: V. dispar induces reduced testosterone levels and upregulation of BAFF, leading to intrahepatic B cell expansion, which serves as the common pathogenic basis for AIH and PBC. The presence of S100 and PDC-E2 subsequently drives further maturation of these expanded B cells and promotes Th17 cell activation, thereby determining the phenotypic divergence between AIH and PBC.

Background and aims: Cyclin E1 is a canonical regulator of cell cycle progression known to promote liver fibrosis and hepatocarcinogenesis. However, its precise contribution to hepatic immune responses remains poorly understood. We investigated whether Cyclin E1 regulates macrophage-associated inflammation and acute immune-mediated liver injury. Methods: Hepatic immune populations were analyzed in untreated and concanavalin A-treated wildtype and constitutive Ccne1-/- mice by flow cytometry. Liver injury was assessed by survival, histopathology, and caspase activation. Inflammatory mediators were quantified by qPCR and ELISA. Bone marrow-derived macrophages were examined during differentiation and pro-inflammatory polarization using flow cytometry, cytokine measurements, and RNA-sequencing. Lipid nanoparticle-mediated delivery of Ccne1-specific siRNA was evaluated in J774A.1 macrophage-like cells. Results: Under homeostatic conditions, Ccne1-/- mice exhibited reduced hepatic immune cell numbers, including Kupffer cells and CD4+ and CD8+ lymphoid cells. Following concanavalin A administration, Ccne1-/- mice showed improved survival, reduced hepatic necrosis, and diminished caspase-3 and caspase-8 activation. Protection was associated with reduced Kupffer and CD8+ lymphoid cell abundance and attenuated inflammatory mediator expression. Cyclin E1 deficiency did not substantially alter bone marrow-derived macrophage differentiation or cell cycle distribution. However, pro-inflammatory Ccne1-/- macrophages showed reduced interleukin-6 expression, attenuated inflammatory gene programs, and lower inferred IRF1 and NF-{kappa}B1 activity. Ccne1 knockdown similarly reduced interleukin-6 expression in pro-inflammatory J774A.1 cells. Conclusions: Cyclin E1 contributes to hepatic immune homeostasis and promotes macrophage-associated inflammatory signaling during immune-mediated hepatitis. Its inflammatory function is uncoupled from overt changes in macrophage cell cycle progression and may involve regulation of IRF1- and NF-{kappa}B-associated transcriptional programs. Targeting Cyclin E1 may therefore provide a strategy to attenuate selected inflammatory responses in liver disease.

Liver cancer remains a major global health burden with high mortality and limited treatment response prediction tools. Patient-derived cancer organoids have emerged as promising preclinical models that recapitulate tumor heterogeneity; however, the biological significance of morphological diversity within established organoids remains poorly characterized in hepatocellular carcinoma (HCC). In this exploratory study, we investigated whether distinct organoid growth phenotypes reflect underlying tumor biology and correlate with clinical outcomes. We established liver cancer organoids from resected tumor tissues of 27 patients and analyzed their clinical, histological, and genomic characteristics. Organoids were classified morphologically into cystic and solid types. Whole exome sequencing (WES) was conducted on six matched tumor-organoid pairs to assess genomic fidelity. Associations between organoid establishment, growth characteristics, and clinical parameters were statistically evaluated. Progression-free survival (PFS) was analyzed using the Kaplan-Meier method and univariate Cox proportional hazards regression. Organoids were successfully established in 13 of 27 cases (48.1%). Solid-type organoids were significantly associated with shorter PFS compared to cystic types (HR = 13.91; p = 0.0039, log-rank test). Organoid establishment was more frequent in older patients (>70 years), those with HBV infection, and tumors with positive {beta}-catenin expression. WES analysis demonstrated high concordance in somatic mutation profiles and variant allele frequency distributions between tissues and corresponding organoids. In univariate Cox regression, organoid growth pattern (solid vs. cystic) showed a significant association with PFS within this exploratory cohort (p = 0.0207). Patient-derived liver cancer organoids preserved the genomic and histopathological features of the original tumors. Notably, solid morphology was associated with shorter PFS, suggesting that organoid growth phenotype may serve as a supplementary indicator of tumor biological behavior in HCC. Given the modest cohort size and the absence of multivariate analysis, these preliminary findings should be interpreted with caution and warrant further large-scale validation.

Alcohol-associated liver disease (ALD) is a major cause of liver-related morbidity and mortality, yet no targeted, disease-modifying therapy exists and the immune mechanisms driving disease progression remain poorly defined. Acetylcholine-producing cholinergic immune cells have emerged as regulators of homeostasis across tissues and in disease, but their role in alcohol-induced hepatic stress is unknown. Here, we characterized the hepatic cholinergic immune landscape during alcohol-induced stress using flow cytometry and single-cell RNA-sequencing of ChAT-eGFP reporter mice. Alcohol feeding expanded hepatic cholinergic immune cells, with T cells constituting a substantial and dynamic fraction of this population that showed a broad increase in acetylcholine signaling and shifted towards a repressed, anergy-like transcriptional state. CD4 T cells underwent coordinated suppression of cholesterol biosynthesis, while CD8 T cells instead adopted a cytotoxic activation program. Together, these findings identify cholinergic T cell signaling, and cholesterol metabolism within CD4 T cells specifically, as a previously unrecognized adaptive response to alcohol-induced liver stress, nominating candidate therapeutic targets for a disease that is marred by critically limited treatment options.

Background & AimsCurrent nucleos(t)ide analogs efficiently suppress hepatitis B virus (HBV) replication but have limited effects on viral transcription from covalently closed circular DNA (cccDNA) and integrated HBV DNA. We aimed to identify clinically applicable compounds that directly inhibit HBV transcription by screening FDA-approved drugs. Approach & ResultsScreening of 1,470 FDA-approved compounds using an HBV enhancer I/X promoter reporter system identified vorapaxar and aripiprazole as potent inhibitors of viral promoter activity. Both compounds suppressed HBV replication in HBV-producing cells, HBV-infected HepG2-hNTCP cells, and primary human hepatocytes. Aripiprazole reduced hepatocyte nuclear factor 4 (HNF4) protein levels through an ERK/JNK-dependent pathway and inhibited HBV core promoter activity, whereas vorapaxar acted independently of HNF4. Both compounds suppressed enhancer I/X promoter activity through inhibition of STAT3 signaling. Vorapaxar inhibited PAR-1-mediated SRC, EGFR, and STAT3 activation, while aripiprazole suppressed SRC-STAT3 signaling independently of EGFR. PAR-1 activation enhanced HBV transcription, whereas PAR-1 knockdown reduced promoter activity and viral RNA expression. Both compounds also reduced HBV replication in human liver chimeric mice at clinically relevant exposure levels without apparent severe toxicity. ConclusionsVorapaxar and aripiprazole suppress HBV transcription and replication through distinct host signaling pathways. These findings identify PAR-1-STAT3 signaling as a previously unrecognized regulator of HBV transcription and suggest that host-targeting approaches may complement current therapies by suppressing viral gene expression from both cccDNA and integrated HBV DNA. Impact and implicationsCurrent nucleos(t)ide analogues effectively suppress HBV reverse transcription but have limited effects on viral transcription from cccDNA and integrated HBV DNA, highlighting the need for therapies targeting viral gene expression. We identify PAR-1- STAT3 signaling as a previously unrecognized regulator of HBV transcription and demonstrate that two clinically approved drugs, vorapaxar and aripiprazole, suppress HBV replication through distinct host signaling pathways. These findings are relevant to researchers developing host-targeting antivirals and to clinicians seeking complementary therapeutic strategies beyond current nucleos(t)ide analogue therapy. Although further clinical validation and combination studies are required, our results provide a rationale for repurposing approved drugs and for developing transcription-targeting therapies that may complement existing treatments for chronic hepatitis B. HighlightsO_LIVorapaxar and aripiprazole suppress HBV through distinct host pathways. C_LIO_LIBoth drugs inhibit HBV replication in vitro and in humanized liver mice. C_LIO_LIPAR-1 inhibition reduces HBV transcription by blocking SRC/EGFR/STAT3 signaling. C_LIO_LIPAR-1-STAT3 signaling is a novel regulator of HBV transcription. C_LIO_LIHost-targeting antiviral therapy complements current HBV treatment. C_LI

Biliary Atresia (BA) is the leading cause of pediatric liver transplantation. Given the heterogeneity of the disease, outcomes after diagnosis remain unpredictable. A multiscale atlas of BA hepatic tissue established early lymphatic dysplasia in infants that later proceed toward liver failure and transplantation (severe BA). An architecturally distorted, immature and CCL21-high lymphatic vasculature marked severe BA, along with an expanding cholangiocyte compartment pivoting toward immune-reactive MMP7/SOX9-high states. Hepatocyte-to-biliary transdifferentiation emerged broadly across BA- and non-BA-cholestatic injuries, while dedifferentiation and acute-phase-reactions were specific to severe BA. Functionally, lymphatic endothelial tissue, isolated from severe BA livers, induced an analogous LGR5- and SOX9-positive epithelial progenitor response when assembled with cholangiocytes as organoids. Further experiments revealed that lymphatic endothelium signals ectopically on liver epithelium via CCL21-CCR7-axis after BA-specific inflammatory priming. CCL21-depletion strategies mitigated the BA-specific MMP7-program. In sum, a maladaptive lymphatic endothelial dysplasia perturbs intrahepatic epithelium in severe BA and offers CCL21 as a possible target for epithelial stability.