Hepatology

Purpose Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major cause of chronic liver disease and liver-related morbidity worldwide. Although dietary factors may influence MASLD progression, the long-term liver-specific implications of artificially sweetened beverage (ASB) intake remain unclear. We aimed to examine the association between ASB intake and the risk of liver-related adverse events and liver-related death among individuals with MASLD. Methods This prospective cohort study included 50,562 participants with MASLD from the UK Biobank. ASB intake was assessed using 24-hour dietary recalls and categorized as 0, >0-1, and >1 serving/day. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for liver-related adverse events and liver-related death. Restricted cubic spline models were used to assess dose-response patterns, and competing-risk analyses were performed by treating liver-related death as a competing event for liver-related adverse events. Additional substitution, subgroup and sensitivity analyses were conducted to evaluate the robustness of the findings. Results During a median follow-up of 12.8 years, 292 liver-related adverse events and 91 liver-related deaths occurred. Compared with participants reporting no ASB intake, those consuming >1 serving/day had a higher risk of liver-related adverse events in the fully adjusted model (HR 1.40, 95% CI 1.02-1.93; P = 0.039), whereas the association for >0-1 serving/day was not statistically significant (HR 1.26, 95% CI 0.92-1.71; P = 0.149). The risk of liver-related adverse events increased across ASB intake categories (P for trend = 0.023). Restricted cubic spline analysis indicated a positive linear association between ASB intake and liver-related adverse events (P-overall <0.001; P-nonlinearity = 0.72). In competing-risk analysis, the association for >1 serving/day remained consistent after accounting for liver-related death as a competing event (sub-HR 1.40, 95% CI 1.02-1.93; P = 0.038; Gray test P = 0.006). The association was robust in sensitivity analyses. ASB intake was not significantly associated with liver-related death, and beverage substitution analyses showed no significant associations. Conclusion Among individuals with MASLD, high ASB intake, particularly >1 serving/day, was associated with an increased risk of liver-related adverse events, but not liver-related death. This association was consistent across dose-response, competing-risk, and sensitivity analyses, suggesting that high ASB intake may represent a potential dietary risk marker for adverse liver outcomes in MASLD.

Background and AimsAcute-on-chronic liver failure (ACLF) is associated with high short-term mortality, but substantial heterogeneity among existing diagnostic and prognostic models results in inconsistent patient identification and risk assessment. We conducted a systematic head-to-head comparison of major ACLF diagnostic and prognostic models to evaluate concordance, short-term mortality prediction and clinical utility, with the goal of informing harmonization of ACLF assessment. MethodsWe analysed 3,370 patients with acute decompensation of cirrhosis in the COSSH cohort, with external validation in an independent Ambi-Spective cohort from India (n=2,055). Five ACLF diagnostic models were evaluated for identification of patients at risk of 28-day mortality. Reclassification was assessed using net reclassification improvement. Prognostic scores were compared using concordance index, integrated discrimination improvement, calibration, and decision-curve analysis. ResultsDiagnostic frameworks identified markedly different proportions of ACLF. A-TANGO and COSSH-ACLF classified the largest high-risk populations while maintaining substantial short-term mortality and balanced sensitivity-specificity profiles. Compared with COSSH-ACLF, A-TANGO improved net reclassification by 7.7%, with further gains versus EASL-CLIF (11.8%), APASL-ACLF (36.4%), and NACSELD-ACLF (45.9%). In the external cohort, A-TANGO and COSSH-ACLF showed similar discrimination and identified comparable proportions of patients. Combined application of the two models delineated three clinically meaningful strata, identifying a discordant intermediate-risk group with approximately 11% 28-day mortality. Among prognostic scores, COSSH-ACLF II and A-TANGO OF scores demonstrated strong and complementary performance across cohorts. ConclusionsOutcome-anchored ACLF definitions converge in identifying patients at highest short-term risk across diverse populations. Alignment between A-TANGO and COSSH-ACLF, together with identification of an intermediate-risk phenotype, supports a data-driven framework for improving consistency and advancing global harmonization of ACLF diagnosis and risk stratification.

Background and AimsSteatotic liver disease (SLD) is characterized by excessive lipid accumulation in hepatocytes, and alcohol consumption may modify the disease course, but the evidence is inclusive. This systematic review and meta-analysis aimed to holistically evaluate the impact of mild, moderate, and high levels of alcohol consumption on hepatic and extrahepatic outcomes in SLD. MethodsWe systematically searched EMBASE, MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials for relevant studies. The study outcomes included liver related events, malignancy, mortality and cardiovascular disease among adults with SLD who consumed alcohol. ResultsOf 2228 records identified, twenty-six studies comprising 466611 adults with SLD were included. High alcohol consumption was associated with an increased risk of liver-related events compared with abstinence (2.97, 95% CI 1.61-5.50; p<0.001), and a similar association was observed among alcohol drinkers overall (HR 1.93, 95% CI 1.60-2.33; p<0.001). Moderate alcohol consumption was associated with a higher incidence of malignancy (HR 1.41, 95% CI 1.13-1.78; p=0.677). In contrast, mild alcohol consumption was associated with lower all-cause mortality compared with abstinence (HR 0.88, 95% CI 0.78-0.98; p=0.001). No association was observed between alcohol consumption and cardiovascular disease incidence or hepatocellular carcinoma ConclusionsAlcohol intake may increase the risk of liver-related complications and cancer risk in individuals with SLD. Mild alcohol consumption was associated with lower all-cause mortality, and alcohol intake showed no association with cardiovascular disease incidence. Further studies are needed to clarify the dose-dependent effects of alcohol on hepatic and extrahepatic outcomes in SLD.

Background Liver fibrosis (LF) represents a pivotal pathological phase in the advancement of chronic liver disorders toward cirrhosis. Amino acid metabolism reprogramming plays a pivotal role in its pathogenesis, yet the underlying molecular mechanisms remain incompletely understood. Methods Integrating three public datasets (GSE14323, GSE84044, and GSE136103) with amino acid metabolism-related gene sets, we performed consensus clustering, machine learning algorithms, functional enrichment analysis, immune microenvironment composition, regulatory network construction, and drug prediction. Results Fibrotic samples were classified into two amino acid metabolism-related subtypes with distinct immune landscapes and functional phenotypes. Through integrated analysis of differentially expressed genes (DEGs) common to both subtypes, fibrotic versus control comparisons, and amino acid metabolism-related gene sets, four biomarkers, GSTP1, LDHB, OXCT1, and PTGDS, were identified. These biomarkers were enriched in pathways related to epithelial-mesenchymal transition, interferon responses, and TNF/NF-{kappa}B signaling. Notably, GSTP1 and LDHB positively correlated with M1 macrophage infiltration and negatively with regulatory T cell abundance. Single-cell transcriptomic analysis revealed that cholangiocytes expressed all four biomarkers with elevated levels in fibrosis and interacted with macrophages/mesenchymal cells via MIF-CD74/CXCR4. Regulatory network analysis highlighted key modulators, including MALAT1, hsa-miR-3163, OXCT1, SMAD4, and RELA. Furthermore, 5-fluorouracil was predicted as a multi-target compound, with the strongest predicted binding affinity for OXCT1. In vitro validation confirmed the upregulation of GSTP1 and LDHB, aligning with the bioinformatics findings. Conclusion This study identified four amino acid metabolism-related biomarkers, revealing immune heterogeneity and cholangiocyte-centered intercellular communication in LF. These findings establish a foundation for biomarker-based diagnosis, subtype-guided patient stratification, and the development of cell-type-specific therapeutic strategies in LF.

Background: Black patients and individuals with low socioeconomic status (SES) face significant disparities in accessing curative therapies for hepatocellular carcinoma (HCC), including liver transplantation. This study aimed to develop provider-co-created intervention prototypes in response to patient-identified barriers and recommendations. Methods: A human-centered design session with hepatology and transplant providers at a large academic medical center was conducted. Prior to the session, participants were presented with barriers and preliminary solutions identified through an earlier human-centered design session with Black and low-SES patients. Using structured ideation methods, including brainwriting, challenge mapping, and concept voting, providers co-created intervention prototypes. Final concepts were synthesized from patient insights, provider input, and design methods using affinity diagramming and concept modeling. Results: Nine providers participated in the session. They focused on three key areas for intervention: inefficiencies in transplant pre-evaluation, inadequate social support, and information overload. Solutions included: (1) a structured triage pathway to standardize referrals and reduce delays; (2) a peer navigator model to guide patients through the transplant process; and (3) a multimodal transplant education roadmap to improve comprehension and engagement. These prototypes addressed both patient- and system-level barriers. Conclusions: Protypes developed through provider-led design, grounded in patient-identified barriers and co-created ideas, can yield actionable, scalable strategies to advance equity in HCC care. Future work will refine these prototypes through patient feedback and pilot them in clinical settings.

Background and Study Aims Fully covered, self expandable metal stents (FCSEMS) are used to treat biliary strictures. FCSEMS with transmural side holes may facilitate cystic duct drainage to mitigate risk of cholecystitis and impact other stent-related adverse events such as migration and occlusion. This study compared rates of premature stent occlusion and acute cholecystitis among patients with biliary strictures who underwent first time placement of a FCSEMS with or without transmural side holes. Patients and Methods This was a retrospective cohort study of adults who underwent endoscopic retrograde cholangiopancreatography (ERCP) with FCSEMS between April 2022 to April 2025 for malignant or benign extrahepatic bile duct strictures. Patients were followed for a minimum of 9 months or through planned stent removal. The primary outcome was premature bile duct occlusion. The secondary outcome was acute cholecystitis among patients with an intact gallbladder. Results Among 219 patients meeting enrollment criteria, 57 (26%) had side holes. The rate of premature stent occlusion was similar with transmural side holes (12%) vs. without (11%, HR 1.02, 95% CI 0.42 2.43, p = 0.96). Among patients with an intact gallbladder (n=129), acute cholecystitis rates were similar with side holes (6%) or without (4.8%, HR 1.01, 95% CI 0.22 4.5, p = 0.99). Conclusions FCSEMS stents with side holes do not reduce rates of premature bile duct stent occlusion or acute cholecystitis compared to FCSEMS without side holes.

Background and AimsThe incidence of hepatocellular carcinoma (HCC) is increasingly driven by metabolic risk factors, including obesity and iron overload. Although high-fat and high-iron diets independently promote hepatocarcinogenesis, their shared and distinct molecular effects remain unclear. We sought to define how dietary fat and iron differentially shape HCC development. ApproachMale C3HeB/FeJ mice were exposed to long-term high-fat (HFD), high-iron (HID), or combined (HFD+HID) diets for 16.5 months. Tumor burden, hepatic iron distribution, mTOR signaling, oxidized phospholipid (OxPL) accumulation, and transcriptomic alterations across normal, adjacent non-tumor, and tumor liver tissues were analyzed using biochemical, histological, and RNA sequencing approaches. ResultsAll diets induced HCC with comparable tumor burden. HID increased iron levels in non-tumor liver tissue but resulted in relative iron depletion within tumors, indicating tumor-specific iron utilization. Tumors from all diet groups showed robust mTOR activation and increased OxPL accumulation, with stronger oxidative stress signatures in HFD and HFD+HID tumors. Transcriptomic analyses revealed conserved oncogenic programs alongside diet-specific signatures, with HFD exerting a dominant effect on metabolic reprogramming and gene dysregulation, whereas HID preferentially enhanced immune and inflammatory signaling. Progressive, monotonic changes in gene expression were observed across disease stages. Cross-species analyses linked diet-induced mouse tumors to immunologically "hot" human HCC subtypes. ConclusionsDietary fat and iron promote HCC through overlapping yet distinct molecular pathways, highlighting metabolic and immune mechanisms as key targets in diet-associated liver cancer.

Hepatocellular carcinoma (HCC), a leading cause of cancer death, has a dynamic and heterogeneous tumor microenvironment (TME) that drives progression and therapeutic resistance. We previously elucidated that apoptosis antagonizing transcription factor (AATF) drives angiogenesis in HCC. However, its role in TME remains unexplored. We employed an orthotopic xenograft mouse model, implanting human HCC cells into the liver, and achieved liver-specific silencing via tail vein injection of AAV8 carrying mouse-specific siAATF or siControl. Histological, biochemical, and molecular analyses, combined with whole-genome transcriptomics mapped to mouse and human genomes, were used to study TME and tumor compartments separately. Silencing of AATF in the TME significantly reduced tumor growth compared with controls. Furthermore, AATF loss disrupted key processes in TME, including inflammation, immune response, angiogenesis, and extracellular matrix remodeling. Mechanistically, TGF-{beta} signaling was significantly suppressed in the TME, thereby affecting tumor cell cycle and metabolic activity, ultimately leading to tumor regression. The long noncoding RNA (lncRNA) analysis identified MIR100HG as a key downstream regulator of AATF in the TGF-{beta} signaling pathway. These findings expand the oncogenic role of AATF to include regulation of the TME via the AATF-MIR100HG-TGF-{beta} axis, highlighting its potential as a therapeutic target in HCC.

Background & Aims: ACLF is defined differently by APASL (acute hepatic dysfunction) and by organ failure-based frameworks including EASL-CLIF and the recently developed A-TANGO score. Whether these definitions identify competing populations or sequential stages of the same syndrome remains unresolved, with direct implications for the timing of intervention. We tested whether APASL-defined ACLF can be integrated into the A-TANGO framework to identify a clinically actionable patient population. Methods: 4,024 patients hospitalised with acute decompensation of cirrhosis in a multicentre cohort were classified simultaneously by APASL and A-TANGO criteria. Mortality, progression to A-TANGO ACLF among A-TANGO-negative patients, and reversal of ACLF were assessed using Fine-Gray competing-risk models with death as a competing event. EASL-CLIF analyses were performed as sensitivity analyses. Results: A-TANGO-negative/APASL-positive patients comprised 8.7% of the cohort and had higher 90-day mortality than A-TANGO-negative/APASL-negative patients (22.3% vs 14.4%, p=0.001), despite similar 28-day mortality. Once A-TANGO ACLF was established, 28-day mortality was high irrespective of APASL status (45.4% in APASL-positive and 56.0% in APASL-negative patients). Among A-TANGO-negative patients, 53.5% of APASL-positive vs 27.9% of APASL-negative patients progressed to A-TANGO ACLF within 28 days, with APASL positivity independently predicting progression (adjusted sHR: 2.30, 95%CI: 1.90-2.77). Within A-TANGO-negative/APASL-negative patients an A-TANGO OF score [&ge;]8 independently enriched for progression (52% vs 19%). A-TANGO reversal occurred in 17.1% and was independently reduced by APASL positivity (adjusted sHR: 0.756, 95%CI: 0.586-0.975), while APASL reversal was rare (4.0%). EASL-CLIF sensitivity analyses were directionally consistent. Conclusions: APASL-defined ACLF does not compete with A-TANGO; it occupies an upstream position on the same disease trajectory. A-TANGO-negative/APASL-positive patients and A-TANGO-negative/APASL-negative patients with A-TANGO OF [&ge;]8 represent complementary pre-ACLF populations suitable for prevention trials and enrichment strategies.

HighlightsCERAMIC enables continuous and high-capacity lineage tracing of liver tumor initiation Fatty liver-associated hepatocytes acquire regenerative and premalignant cell states before malignant transformation Lineage reconstruction identifies Hep_Bi-zonal cells as the cellular origin of liver tumor initiation Transcriptional and regulatory programs distinguish tumor-fated hepatocytes from failed-to-transform lineages Peroxisomal metabolism is required for progenitor-state formation and liver tumor initiation Spatial remodeling identifies a macrophage niche associated with tumor-fated hepatocytes Dual ontogenies and functional specialization of lipid-associated macrophages shape the tumor-fated hepatocyte niche Fatty liver disease predisposes to primary liver cancer, yet the lineage routes and niche mechanisms that select rare tumor-fated hepatocytes remain unclear. Here we developed CERAMIC, a high-capacity CRISPR-Cas9 lineage recorder that co-recovers editing scars and transcriptomes from single cells, and applied it to an AKT/NRAS-driven model of MASLD-associated liver tumor initiation. Longitudinal lineage, single-cell and spatial analyses revealed a hierarchical trajectory in which Hep_Bi-zonal cells, rather than Hep_CVlike cells, generated regenerative and neoplastic hepatocyte progenitor states that progressed toward both hepatocellular carcinoma and intrahepatic cholangiocarcinoma lineages. Tumor-fated cells preferentially expanded along a remodeled midlobular-periportal axis and depended on ACOX1-mediated peroxisomal beta-oxidation to withstand lipotoxic and oxidative stress. Spatial and lineage analyses further identified a sequential lipid-associated macrophage niche, in which monocyte-derived LAMs engaged tumor-fated hepatocytes through an LGALS9-P4HB axis, and P4HB inhibition suppressed tumor expansion. These findings define liver tumor initiation as a lineage-restricted process licensed by peroxisomal metabolic adaptation and macrophage-derived niche signals.

Hepatocellular carcinomas (HCC) are genetically heterogeneous cancers frequently characterized by MYC gene amplification or hyperactivating {beta}-catenin (CTNNB1) mutations. Analysis of TCGA transcriptomics revealed that MYC-driven HCC tumors have decreased expression of mtDNA-encoded genes, but increased expression of nuclear-encoded mitochondrial genes. To investigate this apparent discrepancy, we generated MYC- and CTNNB1-driven murine HCCs, all of which displayed aberrant mitochondrial metabolism. Notably, MYC-driven tumors exhibited significant reductions in OXPHOS and TCA cycle activity that correlated with increased ROS levels, as well as elevated mitochondrial turnover through mitochondrial fission and mitophagy. MYC induces the expression of nuclear respiratory factor 1 (NRF1), which regulates DRP1 and other genes to promote receptor-mediated mitophagy. Knocking out DRP1 reduced mitophagy and ROS levels and promoted survival of HCC-bearing mice. These results identify elevated mitochondrial turnover as a potential therapeutic target in MYC-driven HCC. SignificanceHepatocellular carcinoma can arise from multiple oncogenes, making targeted therapy more difficult. Here we show that tumors with MYC amplification lose mitochondrial function via fission and mitophagy upregulation. Targeting mitochondrial quality control results in increased survival suggesting a therapeutic window in MYC-driven HCC.

Background and AimsA major goal of personalised liver oncology is the ability to make targeted predictions about cancer-specific toxicity, however there are limited methods available. To address this, we validated the performance of our bioinformatics framework, TARGET-SL, through ex vivo drug screening. MethodsUsing TARGET-SL we predicted gain of function (GOF), loss of function (LOF) and synthetic lethal (SL) genetic events, and corresponding drug candidates. We validated drug predictions across hepatocellular carcinoma (HCC) cell lines, and a cohort of HCC and cholangiocarcinoma (CCA) patient-derived organoids (PDOs). ResultsFor HCC cells and PDOs we found 37.5% and 25% of the respective selected compounds induced unique target-specific growth inhibition based on genetic biomarkers, suggesting novel biomarker-driven drug sensitivities. ConclusionsOur analyses demonstrate TARGET-SLs potential to enhance personalized drug screening for liver cancer, by focusing on genetically informed targets. This will reduce experimental costs and accelerate the pace of therapeutic discovery. Impact and ImplicationsPrimary liver cancer (PLC) is a cancer with poor prognosis, and current therapies increase survival only for a minority of patients. Through the application of TARGET-SL we can predict, for each patient, the essential genes and corresponding small molecule inhibitors. These data support further investigation in larger patient cohorts and offer the possibility to specify new small molecule inhibitors and to repurpose current drugs for PLC treatment. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/725819v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@10cb252org.highwire.dtl.DTLVardef@8f3049org.highwire.dtl.DTLVardef@ab4467org.highwire.dtl.DTLVardef@17f9d3_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LITARGET-SL can predict gene and drug sensitivities for cell lines and patient-derived organoids C_LIO_LIThis may reduce drug screening costs and accelerate the pace of therapeutic discovery. C_LIO_LITARGET-SL may assist in the repurposing of current drugs and their rapid translation for primary liver cancer C_LIO_LITARGET-SL is tumour-type agnostic, and therefore may have application in other cancers with poor prognosis C_LI

Background & Aims: Liver transplantation improves outcomes in hepatocellular carcinoma (HCC), yet treatment options for patients with tumor recurrence remain limited to tyrosine kinase inhibitors. Glypican-3 (GPC3)-targeted CAR T cells offer a tumor-directed immune-based therapeutic strategy, but their efficacy may be limited by post-transplant immunosuppression. We developed a CAR T cell platform combining CRISPR/Cas9-mediated FKBP1A disruption to confer resistance to FKBP12-dependent immunosuppressive agents, including tacrolimus, everolimus, and sirolimus, with TRAC knockout to eliminate endogenous T cell receptor expression and reduce alloreactivity. Methods: Human T cells were edited using Cas9 ribonucleoprotein complexes targeting FKBP1A and TRAC, expanded, and transduced with an anti-GPC3 CAR construct. Cytokine production and cytotoxicity were assessed in vitro. Antitumor activity under tacrolimus treatment was evaluated in a Hep G2 xenograft model, and xenoreactivity was assessed in a graft-versus-host disease model. FKBP1A/TRAC double-knockout T cells were enriched using mTOR inhibitor selection combined with CD3-based MACS depletion. PBMCs from liver transplant recipients were used to evaluate feasibility for clinical translation during the early post-transplant period. Results: Tacrolimus suppressed wild-type CAR T cell function but not FKBP1A/TRAC double-knockout CAR T cells, which retained cytokine production, cytotoxicity, and in vivo antitumor activity. Cyclosporine A remained suppressive, enabling its potential use as a pharmacologic control strategy. TRAC disruption reduced xenoreactivity. CD3-based MACS depletion and mTOR inhibition achieved functional double-knockout efficiencies greater than 98%, without compromising cell viability. Functional FKBP1A/TRAC knockout CAR T cells were generated from patient PBMC samples 30 days post-transplant. Conclusions: Dual-edited GPC3 CAR T cells resist tacrolimus-based immunosuppression while limiting alloreactivity, supporting their use for recurrent HCC after liver transplantation. Sequential, high-viability selection in a modular cellular engineering framework enables adaptation to alternative tumor targets and next-generation CAR T cell designs.

BackgroundAlkaptonuria (AKU) is a rare autosomal recessive metabolic disorder caused by deficiency of homogentisate 1,2-dioxygenase (HGD), resulting in systemic accumulation of homogentisic acid (HGA), ochronosis, and progressive multisystem disease. Although nitisinone (NTBC) lowers HGA levels, it does not correct the underlying genetic defect and induces hypertyrosinemia, highlighting the need for curative treatment approaches. We evaluated liver-directed adeno-associated virus (AAV)-mediated HGD gene therapy as a potential treatment for AKU. MethodsHgd-deficient (Hgd-/-) mice received liver-directed AAV2/8 vectors expressing codon-optimized human HGD under a liver-specific promoter. Reporter vectors were first used to assess hepatic biodistribution and transduction efficiency. Therapeutic efficacy was subsequently evaluated following AAV2/8-HGD administration (1 x 1012 vg/mouse). HGD expression was assessed by DNAscope, Western blotting, and RT-qPCR. Metabolic correction was determined using targeted LC-MS/MS and untargeted LC-HRMS metabolomics and compared with NTBC-treated Hgd-/- mice. ResultsReporter studies demonstrated liver-predominant transduction, with dose-dependent hepatocyte transduction reaching 89-93% at the highest dose. AAV2/8-HGD treatment produced robust hepatic HGD expression, with codon-optimized human HGD transcript levels approximately 33-fold higher than endogenous murine Hgd expression. Twelve weeks after treatment, plasma and urinary HGA levels were significantly reduced, with plasma HGA restored to near wild-type concentrations. Untargeted metabolomics further demonstrated marked reductions in HGA-derived phase I and II metabolites and revealed significant modulation of tricarboxylic acid cycle metabolism, consistent with partial restoration of metabolic homeostasis. Compared with NTBC-treated mice, AAV2/8-HGD achieved comparable plasma HGA reduction without elevation of upstream tyrosine pathway metabolites. ConclusionsLiver-directed AAV2/8-HGD gene therapy achieved substantial biochemical correction in Hgd-/- mice and restored metabolic flux without inducing hypertyrosinemia. These findings provide proof-of-concept supporting AAV-mediated HGD replacement as a promising long-term therapeutic strategy for AKU.

Background & AimsRare cases of non-hepatotropic virus (NHV) infection in humans can cause severe hepatitis and even acute liver failure. Clinically relevant animal models of NHV-induced hepatitis are limited, contributing to the incomplete understanding of pathological mechanisms. Murine norovirus (MNV) elicits hepatosplenomegaly in mice lacking the antiviral immune effector Signal Transducer and Activator of Transcription-1 (STAT1), providing a model to investigate mechanisms of NHV-induced hepatic pathology. MethodsSTAT1-sufficient and -deficient (Stat1Het, Stat1KO) littermates infected intravenously (i.v.) with MNV strain CR6 were assessed for hepatic inflammation and viral burden. Cell types and molecular pathways associated with hepatic pathology in CR6-infected Stat1KO mice were identified by flow cytometry and RNAseq of liver tissue. The relative importance of hematopoietic vs non-hematopoietic expression of STAT1 in restricting CR6 replication and maintaining tissue homeostasis was assessed in bone marrow chimeras. ResultsMNV CR6 Stat1KO mice developed severe hepatitis with patchy hepatocellular necrosis and localized enrichment of CR6-infected myeloid cells, particularly macrophages. Gene set enrichment analysis (GSEA) of hepatic biopsies isolated from CR6-infected Stat1KO mice suggested dysregulated myeloid cell activation and indicated similarities between murine and human hepatic pathologies. STAT1 expression in hematopoietic cells was protective against hepatic viral dissemination, but hematopoietic STAT1-deficiency permitted persistent hepatic MNV infection, facilitating dysregulated myeloid cell activation and hepatic fibrosis. ConclusionsThese results demonstrate that the role of STAT1 extends beyond restricting MNV dissemination and suggest that STAT1-dependent regulation of myeloid cell activation prevents acute hepatic necroinflammation and secondary fibrosis. This model of MNV-induced hepatitis may prove valuable in elucidating mechanisms of rare clinical complications. SynopsisMechanisms driving acute hepatitis caused by non-hepatotropic viruses are not well understood. We describe a model of non-hepatotropic murine norovirus infection that reliably induces liver pathology and identify a requirement for STAT1 expression in myeloid cells to promote antiviral immunity and hepatic tissue protection. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/720966v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@4ef59forg.highwire.dtl.DTLVardef@1dfac58org.highwire.dtl.DTLVardef@1abe41dorg.highwire.dtl.DTLVardef@d59e9_HPS_FORMAT_FIGEXP M_FIG C_FIG

Liver injury induces rapid transcriptional responses in hepatocytes, yet the chromatin features that distinguish injured hepatocytes from healthy hepatocytes remain poorly understood. Using an integrated functional genomics approach combining bulk RNA-seq, ATAC-seq, and CUT&Tag profiling of H3K27ac and H3K27me3, we define the transcriptional and chromatin landscape of Sox9-expressing hepatocytes, which exhibit gene expression consistent with both hepatocyte and biliary identity. Under homeostatic conditions, Sox9+ hybrid hepatocytes (HybHeps) are rare and confined to the periportal space, while chronic injury induces an expansion of Sox9+ metaplastic hepatocytes (MetHeps). We identify three classes of differentially expressed genes associated with injury-responsive, state-associated, or shared regulatory programs and demonstrate that these classes are governed by distinct chromatin mechanisms. Injury-responsive transcription is driven primarily by dynamic chromatin accessibility remodeling at NF-{kappa}B- and AP-1-enriched regulatory elements, while state-associated and shared programs are reinforced through selective H3K27ac and H3K27me3 modification with comparatively stable accessibility. Relative to conventional hepatocytes, HybHeps encode a permissive chromatin landscape at injury-responsive loci under homeostatic conditions, consistent with epigenetic priming that facilitates rapid inflammatory activation. Projection of mouse-derived gene programs onto a human liver single-cell atlas encompassing both healthy and diseased hepatocytes confirms that SOX9-expressing hepatocytes preferentially engage injury-associated inflammatory modules while attenuating hepatocyte metabolic identity programs. Together, these findings define a chromatin-based regulatory dichotomy between inflammatory responsiveness and hybrid hepatocyte cell state stability, providing mechanistic insight into how differentiated epithelial cells integrate inflammatory signals while preserving cell state.

The hepatic urea cycle is consistently suppressed in liver disease and hepatocellular carcinoma (HCC), but whether loss of individual enzymes contributes to disease initiation and progression remains unknown. Using mice with hepatocyte-specific deletion of argininosuccinate synthase 1 (ASS1), the urea cycle enzyme that condenses citrulline and aspartate into argininosuccinate, we investigated the role of ASS1 in diet and carcinogen-induced liver disease progression. We found that complete loss of hepatic Ass1 is lethal, but high fat diet extends lifespan. Unexpectedly, animals with approximately 85% loss of hepatic Ass1 are completed protected from diet-induced obesity, liver steatosis, fibrosis, and HCC. We determined that hepatic Ass1 loss activates fatty acid oxidation in peripheral oxidative tissues leading to increased energy expenditure and protection from disease phenotypes. Moreover, targeting Ass1 after obesity onset promotes weight loss and reverses liver steatosis. These findings implicate hepatic ASS1 as a novel regulator of whole-body lipid metabolism that can be targeted to prevent obesity, liver disease, and HCC.

Background & Aims: Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is the leading cause of chronic liver disease in children. However, accurate, noninvasive diagnostic tools remain limited. Current screening methods are invasive or lack sensitivity. Breath-based volatile organic compound (VOC) analysis offers a simple approach with potential for point of care screening. This study aimed to identify and validate breath VOC signatures of pediatric MASLD. Approach & Results: We conducted a prospective IRB approved cohort study at the Childrens Hospital of Philadelphia (CHOP). Children aged between 7 and 20 years with MASLD (n=22), as defined by hepatic steatosis either by liver biopsy or imaging and 1 cardiometabolic risk factor, and a control group without MASLD (n=20) were enrolled. Breath samples were collected using a standardized protocol and analyzed by untargeted comprehensive two-dimensional gas chromatography-mass spectrometry (GCGCMS). Machine learning and unsupervised clustering were applied to identify discriminatory VOCs and assess heterogeneity. Untargeted GCGCMS analysis identified a distinct breath VOC signature in children with MASLD compared with non MASLD controls. A Random Forest model achieved a sensitivity of 73% and specificity of 65%, with AUC of 0.84. The VOC 2,4-dimethyl-1-heptene demonstrated strong diagnostic performance in the discovery cohort with a sensitivity of 85%, specificity of 77% and an AUC of 0.81. Unsupervised clustering revealed four MASLD subgroups with distinct volatile phenotypes associated with differences in liver enzymes and metabolic parameters. External validation in a second pediatric cohort confirmed reproducible reductions in o/p-xylene in subjects with MASLD. Conclusions: Pediatric MASLD is associated with a reproducible breath VOC signature identified by untargeted GCGCMS. These findings support breath analysis as a scalable, noninvasive screening and stratification tool for pediatric MASLD and warrant validation in larger, longitudinal studies.

Overnutrition-related liver dysfunction and cancer are increasingly prevalent and highly resistant to immunotherapy. While metabolic dysregulation is a hallmark of hepatocellular carcinoma (HCC), how nutrient overload impairs antitumor immunity remains unclear. Here, we show that short-term Western diet (WD) exposure drives near-complete loss of CD8 T cell infiltration and antitumor function in HCC. We identify dietary linoleic acid (LA), the most abundant {omega}-6 fatty acid, as the dominant immunosuppressive driver. Cancer cell-restricted FADS2-mediated desaturation of LA to longer-chain {omega}-6 PUFAs drives their accumulation in the tumor interstitial fluid, suppressing infiltrating CD8 T cells via lipid peroxidation. FADS2 inhibition restores CD8 T cell function and sensitizes WD-driven HCC to PD-1-based immunotherapy. Further, the Parkinsons disease-associated deglycase DJ-1 protects LA-handling proteins from methylglyoxal-mediated glycation, sustaining tumoral immunosuppressive PUFA production. Across multiple independent human MASLD-HCC cohorts, LA metabolic activity correlates with CD8 T cell impairment, immune exclusion, and immunotherapy resistance. Overall, these studies identify a dietary lipid axis as a therapeutically actionable vulnerability in WD-associated HCC.

BackgroundBiliary atresia (BA) is a severe neonatal liver disease characterized by progressive fibrosis and bile duct obliteration. ObjectiveAlthough immune dysregulation is implicated in the pathogenesis of BA, the specific mechanisms driving bile duct injury remain incompletely understood. This study aimed to characterize tertiary lymphoid structures (TLSs) within extrahepatic biliary remnants (EBRs), identify their cellular mediators, and evaluate the therapeutic potential of targeting IL-21 receptor signaling. DesignWe performed integrated bulk RNA sequencing, single-cell RNA sequencing, spatial transcriptomics, multiplex immunohistochemistry, and flow cytometry on clinical samples from BA patients and non-BA cholestatic controls. TLS maturation was assessed by CD23 immunohistochemistry in EBRs from 148 BA patients and correlated with clinical parameters. Anti-IL-21R antibody treatment was evaluated in a rhesus rotavirus-induced BA mouse model, with treatment initiated on day 4 post-infection. ResultsTLSs were identified in BA EBRs with significantly higher prevalence than in matched liver tissues. Mature TLSs containing CD23 germinal centers were associated with elevated serum matrix metalloproteinase-7, more advanced hepatic fibrosis, and localized autoantibody deposition on injured bile ducts. Single-cell profiling revealed expanded CD4+ T peripheral helper (Tph) cells expressing IL-21 and CXCL13 within TLS-containing EBRs. Tph cells were enriched in peripheral blood of BA patients compared to non-BA cholestatic controls (P = 0.0025), and serum IL-21 was significantly elevated (P < 0.0001). Post-infection IL-21R blockade in the mouse model reduced jaundice incidence, improved weight gain, prevented extrahepatic biliary obstruction, and significantly improved long-term survival. ConclusionTLSs in BA extrahepatic biliary remnants harbor expanded Tph cells associated with IL-21-mediated B cell activation and bile duct injury. IL-21R blockade ameliorated disease in a murine BA model, identifying the IL-21/IL-21R axis as a potential therapeutic target warranting further investigation. Key MessagesO_ST_ABSWhat is already known on this topicC_ST_ABSImmune dysregulation contributes to biliary atresia (BA), with documented lymphocyte infiltration and defective B cell tolerance. However, the cellular mechanisms linking local immune activation to bile duct injury are unclear, and the roles of organized lymphoid structures and specific CD4 T cell subsets in orchestrating local humoral responses have not been characterized. What this study addsThis study demonstrates that mature tertiary lymphoid structures in extrahepatic biliary remnants are associated with disease severity markers and localized bile duct injury in BA. We identify T peripheral helper cells as an expanded IL-21-producing CD4 T cell population within these structures, and show that post-infection IL-21 receptor blockade prevents biliary obstruction and improves survival in a murine BA model. How this study might affect research, practice or policyThese findings identify the IL-21/IL-21R signaling axis as a candidate therapeutic target in BA warranting further preclinical and translational investigation. TLS maturation status in biliary remnants and serum autoantibody levels may serve as potential biomarkers of disease severity, meriting prospective evaluation in clinical cohorts.