Search Results (238)

In drug-induced liver injury (DILI) prediction field, animal models and in vitro cell models are most commonly used. However, animal models require long experimental timelines and may exhibit species-specific differences compared with humans, whereas conventional two-dimensional (2D) cell culture models lack cell-to-cell and cell-to-extracellular matrix (ECM) interaction. Liver organoid models and liver organ-on-a-chip can better simulate the human liver microenvironment; however, the construction of liver organoids requires a long cycle and high costs, while liver organ-on-a-chip systems demand specialized equipment and professional technicians. Herein, we selected the human C3A cell line, characterized by its low cost and facile culture conditions to establish an in vitro three-dimensional (3D) liver model. Briefly, C3A cells were embedded in Matrigel and cultured for 7 days to allow model maturation. Compared with their 2D-cultured cell model, the established 3D model exhibited elevated mRNA expression levels of drug-metabolizing cytochrome P450 enzymes (CYPs). Moreover, the model displayed robust expression of key hepatic biomarkers, as well as bile duct biomarkers. To evaluate the model’s applicability for DILI prediction, we performed toxicity assessments using a panel of six well-characterized hepatotoxicants and three non-hepatotoxic compounds. Notably, the 3D C3A model achieved a sensitivity of 83.3%, specificity of 100%, and overall accuracy of 88.9%. Furthermore, treatment of this model with chlorpromazine, a well-characterized cholangiotoxic agent, resulted in suppressed expression of the bile duct biomarker cytokeratin 19 (CK19) and bile salt export pump (BSEP), accompanied by impaired bile acid transport capacity. Taken together, this study provided a simple, low-cost, easy to culture, and more readily scalable 3D hepatic model in comparison with conventional 2D primary human hepatocyte (PHHs) models and other advanced 3D liver models. Notably, the model displayed dual hepatic and biliary characteristics, supporting predictions of both DILI and drug-induced bile duct injury. It provided a promising in vitro platform for assessing drug-induced hepatobiliary toxicity, with potential to reduce reliance on animal experiments and accelerate early-stage screening of novel pharmaceutical candidates. Full article

Macropinocytosis is an actin-driven endocytic process mediating nonspecific uptake of extracellular fluid through membrane ruffling. Neutrophil macropinocytosis has been reported only in limited descriptive studies, and its signaling mechanisms have not been defined. Here, we provide a characterization of macropinocytosis in primary human neutrophils and investigate signaling pathways that contribute to the regulation of this process. Quantitative flow cytometry using a high-molecular-weight fluid-phase tracer showed that the diacylglycerol (DAG) mimetic 4β-phorbol 12-myristate 13-acetate (4β-PMA) induces macropinocytic activity in primary human neutrophils. Granulocyte macrophage-colony stimulating factor (GM-CSF) and hepatocyte growth factor (HGF) also promoted fluid-phase uptake. Inhibition of actin polymerization or macropinocytosis reduced tracer uptake, confirming dependence on actin-driven machinery. Scanning electron microscopy revealed dorsal membrane ruffling and cup-like structures after stimulation. Mechanistically, DAG-dependent activation of protein kinase C beta (PKCβ) acted upstream of NADPH oxidase 2 (NOX2)-derived superoxide anion production, driving membrane remodeling. Collectively, these findings define a DAG–PKCβ–NOX2–superoxide signaling axis, as a key regulator of macropinocytosis in primary human neutrophils and provide the first mechanistic framework for its redox-dependent regulation. Full article

The liver ranks among the peripheral organs exhibiting the most robust circadian rhythmicity, with glucose homeostasis, lipid metabolism, and bile acid turnover governed by tightly phased diurnal oscillations. Mitochondria execute these programs, their output coordinated with the hepatocyte circadian state. The mitochondrial network undergoes dynamic remodeling across the 24 h cycle, encompassing oscillatory changes in bioenergetics, fusion–fission balance, and quality control. This interplay is bidirectional: core clock components drive rhythmic remodeling via cyclin-dependent kinase 1/mitogen-activated protein kinase (CDK1/MAPK)-dependent phosphorylation of dynamin-related protein 1 (DRP1) and the NAD⁺–SIRT1/SIRT3 axis, while retrograde signals modulate clock amplitude and entrainment. Circadian disruption is associated with mitochondrial dysfunction implicated in MASLD onset and progression to MASH and HCC, though this evidence remains largely correlative and derives predominantly from rodent models. This review integrates clock–mitochondria coupling with metabolic liver disease. Restoring this coupling has been proposed as a candidate chronotherapeutic strategy, supported by preliminary rhythmicity data in primary human hepatocytes and a hepatocellular carcinoma cell line, though causal validation in healthy human liver is lacking. Time-restricted feeding, NAD⁺ precursors, PPAR agonists, and ACC inhibitors converge on clock-regulated pathways and may benefit from circadian-informed timing, though this remains unverified. Full article

Apolipoprotein A1 (APOA1) and paraoxonase 1 (PON1) are key proteins of high-density lipoproteins (HDL). The aim of the present study was to obtain and characterize an in vitro model for endogenous APOA1 and PON1 longstanding upregulation in hepatocytes that can be further used to decipher the mechanisms of their protective action. Cultured human hepatocytes (HuH-7 cell line) were transfected with CRISPR/dCas9 activation plasmids targeting APOA1/PON1 genes. Following selection with specific antibiotics, RNA sequencing was used for the transcriptomic characterization of the transfected hepatocytes. The functionality of the secreted APOA1/PON1 was evaluated as the capacity of the conditioned medium (CM) from transfected HuH-7 to modulate the oxidative and inflammatory stress in TNFα-activated primary human umbilical endothelial cells (HUVEC). The results showed that: (1) a robust, longstanding upregulation (46 days) of endogenous APOA1/PON1 was obtained after CRISPR/dCas9 transfection and antibiotics selection; (2) APOA1/PON1 upregulation led to a modified transcriptomic profile and increased the expression of several antioxidant genes in transfected hepatocytes as demonstrated by RNAseq analysis; (3) secreted APOA1/PON1 were functional as demonstrated by the CM ability to reduce the levels of reactive oxygen species and inflammatory markers (VCAM-1, MCP-1) in TNFα-activated HUVEC. In conclusion, we achieved an experimental model of successful longstanding upregulation of endogenous APOA1 and PON1 in human hepatocytes. The targeted proteins are secreted in a functional form and can be used for deciphering their complex mechanism of protective action in various pathological conditions. Full article

Introduction: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), such as liraglutide (LIR), are widely used in humans to treat type 2 diabetes mellitus, obesity, and non-alcoholic fatty liver disease. In mammals, GLP-1 RAs have been shown to influence hepatic lipid metabolism, although the underlying mechanisms remain unclear. In fish, GLP-1 also plays an important role in regulating hepatic processes, including glycogenolysis, gluconeogenesis, and lipolysis. However, the effects of GLP-1 RAs on liver lipid metabolism in fish remain largely unexplored. Objective: This study aimed to evaluate the effects of LIR on lipid target genes using primary hepatocytes from brown trout as an in vitro model. Methodology: After 24 h, a hepatocyte monolayer culture was established, and cells were exposed for 24 and 48 h to supplemented L-15 medium (control), 0.1% dimethyl sulfoxide in supplemented L-15 medium (solvent control), and five single exposures to LIR at 1, 10, 100, 500, and 1000 nM. After 24 and 48 h, cell viability was assessed using the trypan blue exclusion assay. Gene expression was analysed by real-time qPCR, targeting genes involved in lipogenesis, lipid transport, and cholesterol efflux. Results: No concentration-dependent effects on cell viability were observed. Gene expression analysis showed that LIR exposure modulated the mRNA levels of lipid-related genes, including acetyl-CoA carboxylase (ACC), acyl-CoA long-chain synthetase 1 (Acsl1), and fatty acid synthase (FAS), with time being the main influencing factor. Overall, expression levels were higher at 48 h compared to 24 h. Additionally, dose-dependent effects were observed for ACC expression, with higher LIR concentrations showing significant differences compared to controls. Conclusions: These findings indicate that LIR modulates lipid-related gene expression in primary hepatocytes of brown trout without affecting cell viability. The results suggest that GLP-1 receptor activation may influence key pathways involved in hepatic lipid metabolism, with time-dependent effects playing a predominant role. Overall, this study supports the use of brown trout primary hepatocytes as a suitable in vitro model for investigating hepatic lipid responses to LIR and other GLP-1 receptor agonists, while providing initial insight into their potential effects in fish. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a widespread condition with a complex pathogenesis. Cell-based models are important tools for studying the mechanisms underlying its development and progression. The aim of this review is to analyze the HepaRG, Huh-7, immortalized human hepatocyte (IHH), and primary human hepatocyte (PHH) cell lines for modeling and studying MASLD. HepaRG represents the most metabolically competent immortalized hepatocyte model with preserved biotransformation activity and a physiological bioenergetic response to lipid loading, making it valuable for pharmacological and toxicological studies. Huh-7 is distinguished by its accessibility and suitability for studying steatosis, lipotoxicity, insulin resistance, and paracrine mechanisms of fibrogenesis; however, its use is limited by its tumor origin, impaired carbohydrate metabolism, and low activity of xenobiotic-metabolizing enzymes. The IHH model occupies an intermediate position because of its non-tumor origin and is of interest for studies of senescence, epigenetic regulation, and signaling pathways involved in steatosis, although interpretation of results requires consideration of immortalization-related effects and specific metabolic limitations. PHH remains the most physiologically relevant platform for MASLD modeling, particularly in three-dimensional (3D) and microphysiological formats; however, its use is limited by high cost, interindividual variability, and the limited duration of the differentiated phenotype. Increasing model complexity—from two-dimensional (2D) monocultures to co-cultures, spheroids, and organ-on-chip systems—enhances physiological relevance and enables reproduction not only of steatosis but also of the inflammatory and fibrogenic components of MASLD progression, yet it reduces reproducibility and complicates standardization. Overall, none of the existing models is universal, and the optimal strategy is to select models according to the specific research question. A key direction for future research is the standardization of steatosis induction protocols and the unification of criteria for evaluating results. Full article

Background and Aims: Understanding regulatory interactions between hepatitis B virus (HBV) and host factors is essential for the development of next generation host-directed antiviral therapies and the achievement of a functional HBV cure. Here, we investigated HBV-induced alterations in host gene expression in primary human hepatocytes (PHH) to identify host factors exploited by the virus for replication and persistence. Whole-transcriptome sequencing (WTS) of HBV-infected PHH identified host pathways with potential roles in the HBV life cycle. RNA interference-based functional screening of dysregulated candidate genes identified cyclin L1 (CCNL1) as a key host factor. RNAi-mediated knockdown of CCNL1 reduced HBV gene expression, including hepatitis B surface antigen (HBsAg). Mechanistically, CCNL1 regulates phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (RNAPII) at serine 2 (S2), consistent with a role in transcriptional regulation. CCNL1 knockdown further reduced the binding of total and phospho- (Ser2/Ser5) RNAPII, pan-acetylated histone H3 (H3ac), and H3K27ac to HBV covalently closed circular DNA (cccDNA), indicating impaired cccDNA-dependent transcription. In addition, CCNL1 expression was elevated in chronic hepatitis B patients compared with those with resolved infection. Collectively, these data demonstrate that CCNL1 promotes HBV transcription and replication through modulation of RNAPII phosphorylation and chromatin-associated transcriptional activity, identifying CCNL1 as a potential host susceptibility factor for HBV. Importance: Hepatitis B virus infection remains a major threat to human health in areas with high prevalence. There is need to fully understand the complex interactions between the virus and human host factors/processes to support ongoing efforts to develop anti-HBV therapies that can be used with existing therapies to achieve a better cure. HBV relies on host cellular factors and biological processes to establish and maintain efficient infection, making host–virus interactions attractive targets for therapeutic intervention. Thus, identifying host factors that support and/or restrict HBV infection is essential for understanding the molecular basis of chronic HBV infection and for developing host-targeting anti-HBV drugs. This study identifies cyclin L1 (CCNL1) as a host susceptibility factor that promotes HBV transcription and replication through regulation of RNA polymerase II activity and or post-transcriptional mechanisms. Full article

Steatosis, characterized by excessive fat accumulation in the liver, is a significant precursor to chronic liver disease and hepatocarcinoma. This condition is influenced by multiple contributing factors such as obesity, alcohol consumption, and exposure to chemicals or drugs. Systems biology approaches including transcriptomics and metabolomics can aid in grouping chemicals according to their mode of action. In this study, we analyze transcriptomic and metabolomic data from primary human and transformed hepatocytes, respectively, to differentiate between steatotic and non-steatotic chemicals. Rather than assessing each steatotic compound individually, we pooled several steatotic chemicals in order to minimize compound-specific noise and better identify features associated with the underlying process of steatosis. Differential gene expression analysis revealed established mechanisms involved in steatosis, consistent with the recently updated adverse outcome pathway. Likewise, metabolomic data enabled clear discrimination between steatotic and non-steatotic chemicals. These findings highlight the potential of omics technologies to support chemical grouping based on insights into the molecular mechanisms that drive steatosis development. Full article

Bitter taste receptors (TAS2Rs) are G protein-coupled receptors best known for detecting bitter compounds in the oral cavity. However, their expression patterns and physiological roles in the liver remain largely unexplored. Here, we employed molecular and immunohistochemical approaches to demonstrate that multiple TAS2Rs are expressed in human Hep3B cells and mouse primary hepatocytes (MPHs) and co-localized with β-adrenergic receptors (βARs) at the bile canaliculi. Bioluminescence resonance energy transfer (BRET), cAMP assays, and Western blot analyses revealed that certain TAS2Rs exhibit ligand-dependent coupling preferences for the G protein subunits Gαi1, Gαi2, and Gαi3. This coupling leads to inhibition of cAMP production and a reduction in protein kinase A (PKA) substrate phosphorylation. Biochemical assays further showed that TAS2R activation significantly attenuates βAR-mediated lipolysis, as well as the production of glycerol and free fatty acid in both Hep3B cells and MPHs. These effects were partially reversed by small interfering RNA (siRNA)-mediated knockdown of TAS2Rs. Moreover, studies using a steatotic mouse model demonstrated that bitter compounds inhibit lipid droplet degradation, resulting in hepatic triacylglycerol accumulation. Collectively, these findings reveal a role for TAS2Rs in modulating hepatic lipid metabolism and highlight their potential as therapeutic targets for the prevention and treatment of liver diseases. Full article

Hepatitis B virus (HBV) remains a major global health threat because covalently closed circular DNA (cccDNA) persists in hepatocytes and limits the efficacy of current antiviral therapies. Effective HBV research and drug screening require culture models that recapitulate the complete viral life cycle and allow for quantitative monitoring of replication. In this study, an 11-amino acid luminescent reporter, HiBiT, was inserted at multiple sites within the preS1 region of a genotype D HBV genome, and the C terminus of preS1 was identified as optimal for maintaining robust replication. We then established HepG2-B4 cells stably replicating HiBiT-HBV with HiBiT at the preS1 C terminus. Extracellular HiBiT activity and supernatant levels of HBV-DNA, HBsAg, and HBcAg increased continuously until day 42 and were reduced by nucleos(t)ide analog treatment, and cccDNA was confirmed by Southern blot analysis. Supernatants from HepG2-B4 cells infected naïve HepG2-NTCP cells and primary human hepatocytes, as shown by extracellular HiBiT activity. Transcriptome analysis revealed distinct gene expression changes in HepG2-B4 cells compared with parental HepG2 cells. These findings indicate that the HepG2-B4 system provides a rapid, quantitative, and scalable platform for HBV replication and infection studies and is suitable for mechanistic investigations and high-throughput antiviral screening. Full article

The intestine–liver–muscle axis plays an essential role in drug and nutrient absorption, metabolism, and energy balance. Yet in vitro models capable of recapitulating this inter-organ communication remain limited. Here, we present a pump-free, 3D-printed multi-organ-on-a-chip device that enables dynamic co-culture of Caco-2 intestinal epithelial cells, HepG2 hepatocytes, and primary human skeletal myoblasts (HSkMs) under gravity-driven oscillatory flow. The device consists of five interconnected chambers designed to accommodate Transwell cell culture inserts for intestine and muscle compartments and hydrogel-embedded hepatocyte spheroids in the central hepatic compartment. The device was fabricated by low-cost fused deposition modeling (FDM) using acrylonitrile butadiene styrene (ABS) polymers. Under dynamic rocking, oscillatory perfusion promoted inter-organ communication without the need for external pumps or complex tubing. Biological assessments revealed that dynamic co-culture significantly enhanced the characteristics of skeletal muscle, as indicated by increased myosin heavy chain expression and elevated lactate production, while HepG2 spheroids exhibited improved hepatic function with higher albumin expression compared with monoculture. Additionally, Caco-2 cells maintained stable tight junctions and transepithelial electrical resistance, demonstrating preserved intestinal barrier integrity under dynamic flow. These results establish the device as a versatile, accessible 3D-printed platform for modeling the intestine–liver–muscle axis and investigating metabolic cross-talk in drug discovery and disease modeling. Full article

Drug- and alcohol-induced liver injury involves impaired bile acids or bilirubin secretion, but it is not known how senescence influences the secretion of hepatocytes exposed to drugs and alcohol. In this study, the toxic effects of ritonavir, lopinavir, and alcohol on hepatocyte transporters and the secretion of bile acids and bilirubin were investigated in hydrogen peroxide-induced senescent HepG2 and doxorubicin-induced senescent primary human hepatocytes. In HepG2, intracellular conjugated bilirubin increased upon senescence and extracellular conjugated bilirubin in culture medium was decreased by ritonavir and lopinavir treatment. In the primary hepatocytes, intracellular bile acids or medium bilirubin were not significantly changed upon senescence. However, intracellular bile acids were increased, and medium conjugated bilirubin were decreased in senescent primary hepatocytes treated with alcohol and the two drugs. Transcriptional expressions of adenosine triphosphate (ATP)-binding cassette (ABC) transporters (ABCB4, ABCC6, ABCB11, and ABCD3) were decreased whereas UDP-glucuronosyltransferase (UGT1A1) was increased by ritonavir and lopinavir in senescent HepG2. In senescent primary hepatocytes, expressions of ABCB11, ABCC1, ABCC2, ABCC3, ABCC4, and ABCC6 were apparently reduced whereas UGT1A1 and the cytochrome P450 enzyme CYP7A1 were markedly increased by alcohol combined with ritonavir and lopinavir. Selective ABCC6 knockdown in the primary hepatocytes altered expressions of two senescence markers, Lamin A/C and cyclin-dependent kinase inhibitor CKI (p21), increased expressions of CYP7A1 and hydroxy methyl glutaryl-CoA reductase (HMGCR), and increased intracellular bile acids. Further, anti-cholestasis agents, ursodeoxycholic acid and glycyrrhizin, significantly ameliorated the impaired secretions of bile acids and bilirubin as well as reducing intracellular lipid accumulation and cell death caused by ritonavir, lopinavir, and alcohol in the primary hepatocytes with ABCC6 knockdown. These results indicate that senescence moderately impairs the ABC transporters of hepatocytes and secretion of bile acids or bilirubin, which become worse in the presence of the drugs and alcohol but could be improved by anti-cholestasis agents. Full article

Background: Intestinal failure-associated liver disease (IFALD) is a serious complication in patients receiving parenteral nutrition, often exacerbated by inflammation, lipid overload, and oxidative stress. Nobiletin (NOB), a polymethoxylated flavone, is known for its anti-inflammatory and lipid-regulating properties. Methods: We employed an in vitro model using THLE-2 human hepatocytes and primary human cholangiocytes exposed to Intralipid (INT) and lipopolysaccharide (LPS) to simulate IFALD conditions. NOB was tested at non-toxic concentrations (10 and 25 µM) to assess its protective effects. MTT viability assays, multiplex bead-based immunoassays (MAGPIX), RT-qPCR, and Western blotting were used to evaluate changes in inflammation markers, gene expression, and protein signaling. Moreover, ALT and AST activities were used to assess hepatocellular injury. Results: NOB maintained high cell viability in THLE-2 hepatocytes and cholangiocytes, confirming its low cytotoxicity. NOB normalized ALT and AST activities in both tested cell lines, but the effect reached statistical significance only for ALT in cholangiocytes. Under IFALD-like conditions (LPS+INT), NOB significantly preserved metabolic activity in both cell types. In THLE-2 and cholangiocytes, NOB markedly reduced the phosphorylation of pro-inflammatory proteins JNK, NF-κB, and STAT3, indicating a broad inhibition of inflammatory signaling. Moreover, in THLE-2 cells, NOB upregulated lipid metabolism-related genes (PRKAA2, CYP7A1, and ABCA1) and decreased oxidative stress, thereby enhancing the nuclear translocation of Nrf2 and increasing SOD1 level, which supports the activation of antioxidant defenses. Conclusions: NOB exhibits hepatoprotective properties under IFALD-like conditions in vitro, likely through modulation of inflammation-related signaling and lipid metabolism pathways. Full article

The liver is the central organ in metabolism; however, modeling hepatic diseases remains limited by current experimental models. Animal models frequently fail to predict human liver physiology, while primary hepatocytes rapidly dedifferentiate in culture. We performed comprehensive transcriptomic profiling of induced pluripotent stem cells (iPSCs) differentiation into hepatocyte-like cells (HLCs) under two-dimensional (2D) and three-dimensional (3D) culture conditions. RNA sequencing analysis revealed the sequential activation of lineage-specific markers across major developmental stages: definitive endoderm (FOXA2, SOX17, CXCR4, CER1, GATA4), posterior foregut (PROX1, GATA6), and hepatoblasts (HNF4A, AFP). Comparative analysis demonstrated a markedly enhanced hepatic gene expression of 3D organoids, as demonstrated by a 33-fold increase in HNF4A expression and elevated levels of mature hepatocyte markers, including ALB, SERPINA1, and UGT2B15. However, the 3D cultures retained fetal characteristics (290-fold higher AFP expression) and exhibited significantly impaired metabolic function, with CYP3A4 expression levels reduced by 2000-fold compared to the adult human liver. This partial maturation was further supported by a moderate correlation with adult liver tissue (ρ = 0.57). We demonstrated high reproducibility across five biologically distinct iPSCs lines, including those derived from patients with rare monogenic disorders. The establishment of quantitative benchmarks provides a crucial tool for standardizing in vitro liver models. Furthermore, we delineate the specific limitations of the current model, highlighting the need for further protocol optimization to enhance metabolic maturation and P450 enzyme activity. Functional validation of metabolic activity (CYP enzyme assays, albumin secretion) was not performed; therefore, conclusions regarding hepatocyte functionality are based on transcriptomic evidence. Full article

This study evaluated hepatic pathological and phenotypic alterations, along with the inflammatory response, following sequential dengue virus (DENV) infection in Callithrix penicillata, a relevant model for human endemic scenarios. Twenty-six animals were initially infected subcutaneously with DENV-3. Thirteen were euthanized between 1 and 7 days post-infection (dpi) to assess the acute phase, and up to 60 dpi for the convalescent phase. The remaining animals received a secondary DENV-2 infection two months later. Liver samples underwent histopathological and immunohistochemical analysis. Viral antigens were identified in hepatocytes, Kupffer cells, and Councilman bodies. Observed liver changes included apoptosis, lytic necrosis, midzonal inflammation, Kupffer cell hyperplasia and hypertrophy, sinusoidal dilation, and hemosiderin deposition. Both primary and secondary infections increased activated macrophages, NK cells, S-100 protein, and B lymphocytes. Primary infection was associated with elevated CD4⁺ T cells, IFN-γ, TGF-β, IL-10, and Fas expression, whereas secondary infection induced higher IFN-γ, TNF-α, IL-8, Fas, and VCAM levels. These findings mirror hepatic alterations in severe human dengue cases and underscore the role of direct viral effects and immune dysregulation in liver injury. The results support C. penicillata as a suitable non-human primate model for studying DENV pathogenesis. Full article