Stem Cell-derived Hepatocytes Research Articles

Disturbed function of TBL1X has a differential effect on T3-regulated gene expression in two human liver cell models.

Mutations in TBL1X, part of the NCOR1/SMRT corepressor complex, were identified in patients with hereditary X-linked central congenital hypothyroidism and associated hearing loss. The role of TBL1X in thyroid hormone (TH) action, however, is incompletely understood. The aim of the present study was to investigate the role of TBL1X on T3-regulated gene expression in two human liver cell models. A human hepatoma cell line (HepG2) wherein TBL1X was downregulated using siRNAs, and human-induced pluripotent stem cell-derived hepatocytes (iHeps) generated from individuals with a TBL1X N365Y mutation. Both cell types were treated with increasing concentrations of T3. The expression of T3-regulated genes was measured by qPCR. KLF9, CPT1A, and PCK1 mRNA expression were higher upon T3 stimulation in the HepG2 cells with decreased TBL1X expression compared to controls, while DIO1 mRNA expression was lower. Hemizygous TBL1X N365Y iHeps exhibited decreased expression of CPT1A, G6PC1, PCK1, FBP1, and ELOVL2 compared to cells with the heterozygous TBL1X N365Y allele, but KLF9 and HMGCS2 expression was unaltered. Downregulation of TBL1X in HepG2 cells and the TBL1X N365Y variant in iHeps have differential effects on T3-regulated gene expression. This suggests that TBL1X may play a gene context role in TH action.

An hepatitis B and D virus infection model using human pluripotent stem cell-derived hepatocytes

Current culture systems available for studying hepatitis D virus (HDV) are suboptimal. In this study, we demonstrate that hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) are fully permissive to HDV infection across various tested genotypes. When co-infected with the helper hepatitis B virus (HBV) or transduced to express the HBV envelope protein HBsAg, HLCs effectively release infectious progeny virions. We also show that HBsAg-expressing HLCs support the extracellular spread of HDV, thus providing a valuable platform for testing available anti-HDV regimens. By challenging the cells along the differentiation with HDV infection, we have identified CD63 as a potential HDV co-entry factor that was rate-limiting for HDV infection in immature hepatocytes. Given their renewable source and the potential to derive hPSCs from individual patients, we propose HLCs as a promising model for investigating HDV biology. Our findings offer new insights into HDV infection and expand the repertoire of research tools available for the development of therapeutic interventions.

Genome Engineering of Primary and Pluripotent Stem Cell-Derived Hepatocytes for Modeling Liver Tumor Formation.

Genome editing has demonstrated its utility in generating isogenic cell-based disease models, enabling the precise introduction of genetic alterations into wild-type cells to mimic disease phenotypes and explore underlying mechanisms. However, its application in liver-related diseases has been limited by challenges in genetic modification of mature hepatocytes in a dish. Here, we conducted a systematic comparison of various methods for primary hepatocyte culture and gene delivery to achieve robust genome editing of hepatocytes ex vivo. Our efforts yielded editing efficiencies of up to 80% in primary murine hepatocytes cultured in monolayer and 20% in organoids. To model human hepatic tumorigenesis, we utilized hepatocytes differentiated from human pluripotent stem cells (hPSCs) as an alternative human hepatocyte source. We developed a series of cellular models by introducing various single or combined oncogenic alterations into hPSC-derived hepatocytes. Our findings demonstrated that distinct mutational patterns led to phenotypic variances, affecting both overgrowth and transcriptional profiles. Notably, we discovered that the PI3KCA E542K mutant, whether alone or in combination with exogenous c-MYC, significantly impaired hepatocyte functions and facilitated cancer metabolic reprogramming, highlighting the critical roles of these frequently mutated genes in driving liver neoplasia. In conclusion, our study demonstrates genome-engineered hepatocytes as valuable cellular models of hepatocarcinoma, providing insights into early tumorigenesis mechanisms.

P02-28 Microfluidics technology as a tool to improve maturation and drug metabolism capacity of stem cell-derived hepatocytes in vitro

P02-28 Microfluidics technology as a tool to improve maturation and drug metabolism capacity of stem cell-derived hepatocytes in vitro

Long-term HBV infection of engineered cultures of induced pluripotent stem cell-derived hepatocytes.

HBV infects ~257 million people and can cause hepatocellular carcinoma. Since current drugs are not curative, novel therapies are needed. HBV infects chimpanzee and human livers. However, chimpanzee studies are severely restricted and cost-prohibitive, while transgenic/chimeric mouse models that circumvent the species barrier lack natural HBV infection and disease progression. Thus, in vitro human models of HBV infection are useful in addressing the above limitations. Induced pluripotent stem cell-derived hepatocyte-like cells mitigate the supply limitations of primary human hepatocytes and the abnormal proliferation/functions of hepatoma cell lines. However, variable infection across donors, deficient drug metabolism capacity, and/or low throughput limit iHep utility for drug development. We developed an optimal pipeline using combinations of small molecules, Janus kinase inhibitor, and 3',5'-cAMP to infect iHep-containing micropatterned co-cultures (iMPCC) with stromal fibroblasts within 96-well plates with serum-derived HBV and cell culture-derived HBV (cHBV). Polyethylene glycol was necessary for cell-derived HBV but not for serum-derived HBV infection. Unlike iHep monocultures, iMPCCs created from 3 iHep donors could sustain HBV infection for 2+ weeks. Infected iMPCCs maintained high levels of differentiated functions, including drug metabolism capacity. HBV antigen secretion and gene expression patterns in infected iMPCCs in pathways such as fatty acid metabolism and cholesterol biosynthesis were comparable to primary human hepatocyte-MPCCs. Furthermore, iMPCCs could help elucidate the effects of interferons and direct-acting antiviral drugs on the HBV lifecycle and any hepatotoxicity; iMPCC response to compounds was similar to primary human hepatocyte-MPCCs. The iMPCC platform can enable the development of safe and efficacious drugs against HBV and ultimately help elucidate genotype-phenotype relationships in HBV pathogenesis.

Human-induced pluripotent stem cell-derived hepatocyte platform in modeling of SARS-CoV-2 infection.

Currently, SARS-CoV-2 is still spreading rapidly and globally. A large proportion of patients with COVID-19 developed liver injuries. The human-induced pluripotent stem cell (iPSC)-derived hepatocytes recapitulate primary human hepatocytes and have been widely used in studies of liver diseases. To explore the susceptibility of hepatocytes to SARS-CoV-2, we differentiated iPSCs to functional hepatocytes and tried infecting them with different MOI (1, 0.1, 0.01) of SARS-CoV-2. The iPSC-derived hepatocytes are highly susceptible to virus infection, even at 0.01 MOI. Other than the ancestral strain, iHeps also support the replication of SARS-CoV-2 variants including alpha, beta, theta, and delta. More interestingly, the ACE2 expression significantly upregulated after infection, suggesting a vicious cycle between virus infection and liver injury. The iPSC-derived hepatocytes can support the replication of SARS-CoV-2, and this platform could be used to investigate the SARS-CoV-2 hepatotropism and hepatic pathogenic mechanisms.

Transient growth factor expression via mRNA in lipid nanoparticles promotes hepatocyte cell therapy in mice

Primary human hepatocyte (PHH) transplantation is a promising alternative to liver transplantation, whereby liver function could be restored by partial repopulation of the diseased organ with healthy cells. However, currently PHH engraftment efficiency is low and benefits are not maintained long-term. Here we refine two male mouse models of human chronic and acute liver diseases to recapitulate compromised hepatocyte proliferation observed in nearly all human liver diseases by overexpression of p21 in hepatocytes. In these clinically relevant contexts, we demonstrate that transient, yet robust expression of human hepatocyte growth factor and epidermal growth factor in the liver via nucleoside-modified mRNA in lipid nanoparticles, whose safety was validated with mRNA-based COVID-19 vaccines, drastically improves PHH engraftment, reduces disease burden, and improves overall liver function. This strategy may overcome the critical barriers to clinical translation of cell therapies with primary or stem cell-derived hepatocytes for the treatment of liver diseases.

Oxidative DNA damage contributes to usnic acid-induced toxicity in human induced pluripotent stem cell-derived hepatocytes.

Dietary supplements containing usnic acid have been increasingly marketed for weight loss over the past decades, even though incidences of severe hepatotoxicity and acute liver failure due to their overuse have been reported. To date, the toxic mechanism of usnic acid-induced liver injury at the molecular level still remains to be fully elucidated. Here, we conducted a transcriptomic study on usnic acid using a novel in vitro hepatotoxicity model employing human induced pluripotent stem cell (iPSC)-derived hepatocytes. Treatment with 20 μM usnic acid for 24 h caused 4272 differentially expressed genes (DEGs) in the cells. Ingenuity Pathway Analysis (IPA) based on the DEGs and gene set enrichment analysis (GSEA) using the whole transcriptome expression data concordantly revealed several signaling pathways and biological processes that, when taken together, suggest that usnic acid caused oxidative stress and DNA damage in the cells, which further led to cell cycle arrest and eventually resulted in cell death through apoptosis. These transcriptomic findings were subsequently corroborated by a variety of cellular assays, including reactive oxygen species (ROS) generation and glutathione (GSH) depletion, DNA damage (pH2AX detection and 8-hydroxy-2'-deoxyguanosine [8-OH-dg] assay), cell cycle analysis, and caspase 3/7 activity. Collectively, the results of the current study accord with previous in vivo and in vitro findings, provide further evidence that oxidative stress-caused DNA damage contributes to usnic acid-induced hepatotoxicity, shed new light on molecular mechanisms of usnic acid-induced hepatotoxicity, and demonstrate the usefulness of iPSC-derived hepatocytes as an in vitro model for hepatotoxicity testing and prediction.

A patient-based iPSC-derived hepatocyte model of alcohol-associated cirrhosis reveals bioenergetic insights into disease pathogenesis.

Only ~20% of heavy drinkers develop alcohol cirrhosis (AC). While differences in metabolism, inflammation, signaling, microbiome signatures and genetic variations have been tied to the pathogenesis of AC, the key underlying mechanisms for this interindividual variability, remain to be fully elucidated. Induced pluripotent stem cell-derived hepatocytes (iHLCs) from patients with AC and healthy controls differ transcriptomically, bioenergetically and histologically. They include a greater number of lipid droplets (LDs) and LD-associated mitochondria compared to control cells. These pre-pathologic indicators are effectively reversed by Aramchol, an inhibitor of stearoyl-CoA desaturase. Bioenergetically, AC iHLCs have lower spare capacity, slower ATP production and their mitochondrial fuel flexibility towards fatty acids and glutamate is weakened. MARC1 and PNPLA3, genes implicated by GWAS in alcohol cirrhosis, show to correlate with lipid droplet-associated and mitochondria-mediated oxidative damage in AC iHLCs. Knockdown of PNPLA3 expression exacerbates mitochondrial deficits and leads to lipid droplets alterations. These findings suggest that differences in mitochondrial bioenergetics and lipid droplet formation are intrinsic to AC hepatocytes and can play a role in its pathogenesis.

Elucidating the role of intrinsic adenosine A1 receptors in acute alcoholism using human-induced pluripotent stem cell-derived hepatocytes.

Acute alcoholic hepatitis (AAH) from binge drinking is a serious disease. It is associated with a high mortality rate, especially among young adults. Apoptosis is known to be a primary cause of liver damage, and it can be induced by either intrinsic signaling pathways or by reactive oxygen species (ROS). Adenosine A1 receptors (ADORA1) are known to be involved in ethanol metabolism; however, underlying mechanism is not well understood. For investigating how the intrinsic ADORA1 function in ethanol metabolism in normal human hepatocytes without interference by extrinsic molecules, primary hepatocytes pose a challenge, due to unavoidable contamination by other kinds of cells in the liver. Also, they are difficult to culture stably. As a novel alternative, hepatocytes derived from human-induced pluripotent stem cells were employed because they display similar function to primary hepatocytes and they can be stably cultured. The dynamics and integrity of signal transduction mechanisms were investigated by following chronological changes in gene expression. This shed light on how and when the ADORA1 function and on causal relationships between the pathways and clinical symptoms. The findings of the present study shows that ADORA1 are most activated soon after exposure to ethanol, and transfection of small interfering RNA targeting ADORA1-messenger-RNA (ADORA1-siRNA) into the hepatocytes significantly suppresses production of actin protein and ROS. It suggests that ADORA1 in the liver contribute to apoptosis in acute alcoholism through both intrinsic pathway and ROS activity. Also, actin that is abundant in the cells could be an appropriate biomarker evaluating hepatic function status.

Rapid Self-Assembly Mini-Livers Protect Mice Against Severe Hepatectomy-Induced Liver Failure.

The construction of bioartificial livers, such as liver organoids, offers significant promise for disease modeling, drug development, and regenerative medicine. However, existing methods for generating liver organoids have limitations, including lengthy and complex processes (taking 6-8 weeks or longer), safety concerns associated with pluripotency, limited functionality of pluripotent stem cell-derived hepatocytes, and small, highly variable sizes (typically ≈50-500µm in diameter). Prolonged culture also leads to the formation of necrotic cores, further restricting size and function. In this study, a straightforward and time-efficient approach is developed for creating rapid self-assembly mini-livers (RSALs) within 12h. Additionally, primary hepatocytes are significantly expanded in vitro for use as seeding cells. RSALs exhibit consistent larger sizes (5.5mm in diameter), improved cell viability (99%), and enhanced liver functionality. Notably, RSALs are functionally vascularized within 2 weeks post-transplantation into the mesentery of mice. These authentic hepatocyte-based RSALs effectively protect mice from 90%-hepatectomy-induced liver failure, demonstrating the potential of bioartificial liver-based therapy.

A comparison between different human hepatocyte models reveals profound differences in net glucose production, lipid composition and metabolism in vitro

Hepatocytes are responsible for maintaining a stable blood glucose concentration during periods of nutrient scarcity. The breakdown of glycogen and de novo synthesis of glucose are crucial metabolic pathways deeply interlinked with lipid metabolism. Alterations in these pathways are often associated with metabolic diseases with serious clinical implications. Studying energy metabolism in human cells is challenging. Primary hepatocytes are still considered the golden standard for in vitro studies and have been instrumental in elucidating key aspects of energy metabolism found in vivo. As a result of several limitations posed by using primary cells, a multitude of alternative hepatocyte cellular models emerged as potential substitutes. Yet, there remains a lack of clarity regarding the precise applications for which these models accurately reflect the metabolic competence of primary hepatocytes. In this study, we compared primary hepatocytes, stem cell-derived hepatocytes, adult donor-derived liver organoids, immortalized Upcyte-hepatocytes and the hepatoma cell line HepG2s in their response to a glucose production challenge. We observed the highest net glucose production in primary hepatocytes, followed by organoids, stem-cell derived hepatocytes, Upcyte-hepatocytes and HepG2s. Glucogenic gene induction was observed in all tested models, as indicated by an increase in G6PC and PCK1 expression. Lipidomic analysis revealed considerable differences across the models, with organoids showing the closest similarity to primary hepatocytes in the common lipidome, comprising 347 lipid species across 19 classes. Changes in lipid profiles as a result of the glucose production challenge showed a variety of, and in some cases opposite, trends when compared to primary hepatocytes.

The downregulation of Tapasin in dendritic cell regulates CD8+ T cell autophagy to hamper hepatitis B viral clearance in the induced pluripotent stem cell-derived hepatocyte organoid.

Tapasin, a crucial molecular chaperone involved viral antigen processing and presentation, plays an important role in antivirus immunity. However, its impact on T cell differentiation in the context of virus clearance remains unclear. In this study, we employed induced pluripotent stem cellsto differentiate into hepatocyte-like cell,which were subsequently inserted to the inverted colloidal crystalscaffolds, thus establishing a hepatocyte organoid (HO). By inoculating hepatitis B virus (HBV) particles in the system, we successfully engineered a robust in vitro HBV infection model for at least 3 weeks. Furthermore, we aimed to explore the effects of lentivirus-mediated short hairpin RNA (shRNA) targeting human Tapasin on the differentiation and antiviral function of CD8+ T cells. Specifically, we transfected dendritic cells (DCs) with Tapasin-shRNA and cocultured with T cells. The results demonstrated that Tapasin-shRNA transfected DCs effectively suppressed T cell proliferation and impeded HBV-specific cytotoxic T lymphocyte responses. Our investigation also revealed the role of mTOR pathway activation in reducing autophagy activity within CD8+ T cells. Expressions of autophagy-related proteins, beclin-1, LC3II/LC3I were decreased and PI3K/AKT/mTOR activity was increased in Tapasin-shRNA group. Collectively, our findings elucidate that shRNA targeting the Tapasin gene within DCs inhibits T cell differentiation by reducing autophagy activity to hamper viral clearance in the HBV-infected HO.

Induced pluripotent stem cell-derived hepatocytes reveal TCA cycle disruption and the potential basis for triheptanoin treatment for malate dehydrogenase 2 deficiency

Mitochondrial malate dehydrogenase 2 (MDH2) is crucial to cellular energy generation through direct participation in the tricarboxylic acid (TCA) cycle and the malate aspartate shuttle (MAS). Inherited MDH2 deficiency is an ultra-rare metabolic disease caused by bi-allelic pathogenic variants in the MDH2 gene, resulting in early-onset encephalopathy, psychomotor delay, muscular hypotonia and frequent seizures. Currently, there is no cure for this devastating disease. We recently reported symptomatic improvement of a three-year-old girl with MDH2 deficiency following treatment with the triglyceride triheptanoin. Here, we aimed to better characterize this disease and improve our understanding of the potential utility of triheptanoin treatment. Using fibroblasts derived from this patient, we generated induced pluripotent stem cells (hiPSCs) and differentiated them into hepatocytes (hiPSC-Heps). Characterization of patient-derived hiPSCs and hiPSC-Heps revealed significantly reduced MDH2 protein expression. Untargeted proteotyping of hiPSC-Heps revealed global dysregulation of mitochondrial proteins, including upregulation of TCA cycle and fatty acid oxidation enzymes. Metabolomic profiling confirmed TCA cycle and MAS dysregulation, and demonstrated normalization of malate, fumarate and aspartate following treatment with the triheptanoin components glycerol and heptanoate. Taken together, our results provide the first patient-derived hiPSC-Hep-based model of MDH2 deficiency, confirm altered TCA cycle function, and provide further evidence for the implementation of triheptanoin therapy for this ultra-rare disease. SynopsisThis study reveals altered expression of mitochondrial pathways including the tricarboxylic acid cycle and changes in metabolite profiles in malate dehydrogenase 2 deficiency and provides the molecular basis for triheptanoin treatment in this ultra-rare disease.

Use of stem cell-derived hepatocytes to model liver disease

Use of stem cell-derived hepatocytes to model liver disease

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes.

Per- and polyfluoroalkyl substances (PFAS) are chemicals with important applications; they are persistent in the environment and may pose human health hazards. Regulatory agencies are con­sidering restrictions and bans of PFAS; however, little data exists for informed decisions. Several prioritization strategies were proposed for evaluation of potential hazards of PFAS. Structure-based grouping could expedite the selection of PFAS for testing; still, the hypothesis that structure-effect relationships exist for PFAS requires confirmation. We tested 26 structurally diverse PFAS from 8 groups using human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes, and tested concentration-response effects on cell function and gene expression. Few phenotypic effects were observed in hepatocytes, but negative chronotropy was observed in cardiomyocytes for 8 PFAS. Substance- and cell type-dependent transcriptomic changes were more prominent but lacked substantial group-specific effects. In hepatocytes, we found upregulation of stress-related and extracellular matrix organization pathways, and down-regulation of fat metabolism. In car­diomyocytes, contractility-related pathways were most affected. We derived phenotypic and transcriptomic points of departure and compared them to predicted PFAS exposures. Conservative estimates for bioactivity and exposure were used to derive a bioactivity-to-exposure ratio (BER) for each PFAS; 23 of 26 PFAS had BER > 1. Overall, these data suggest that structure-based PFAS grouping may not be sufficient to predict their biological effects. Testing of individual PFAS may be needed for scientifically-supported decision-making. Our proposed strategy of using two human cell types and considering phenotypic and transcriptomic effects, combined with dose-response analysis and calculation of BER, may be used for PFAS prioritization.

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl7

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl7

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl6

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl6

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl5

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl5

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl4

Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes_Suppl4