A multicellular liver organoid model for investigating hepatitis C virus infection and nonalcoholic fatty liver disease progression.

BACKGROUND AND AIMS: HCV infection can be successfully managed with antiviral therapies; however, progression to chronic liver disease states, including NAFLD, is common. There is currently no reliable in vitro model for investigating host-viral interactions underlying the link between HCV and NAFLD; although liver organoids (LOs) show promise, they currently lack nonparenchymal cells, which are key to modeling disease progression. APPROACH AND RESULTS: Here, we present a novel, multicellular LO model using a coculture system of macrophages and LOs differentiated from the same human pluripotent stem cells (PSCs). The cocultured macrophages shifted toward a Kupffer-like cell type, the liver-resident macrophages present in vivo , providing a suitable model for investigating NAFLD pathogenesis. With this multicellular Kupffer-like cell-containing LO model, we found that HCV infection led to lipid accumulation in LOs by upregulating host lipogenesis, which was more marked with macrophage coculture. Reciprocally, long-term treatment of LOs with fatty acids upregulated HCV amplification and promoted inflammation and fibrosis. Notably, in our Kupffer-like cell-containing LO model, the effects of 3 drugs for NASH that have reached phase 3 clinical trials exhibited consistent results with the clinical outcomes. CONCLUSIONS: Taken together, we introduced a multicellular LO model consisting of hepatocytes, Kupffer-like cells, and HSCs, which recapitulated host-virus intercommunication and intercellular interactions. With this novel model, we present a physiologically relevant system for the investigation of NAFLD progression in patients with HCV.

sEVs from tonsil-derived mesenchymal stromal cells alleviate activation of hepatic stellate cells and liver fibrosis through miR-486-5p.

Mesenchymal stromal cells (MSCs) are considered as a promising therapeutic tool for liver fibrosis, a main feature of chronic liver disease. Because small extracellular vesicles (sEVs) harboring a variety of proteins and RNAs are known to have similar functions with their derived cells, MSC-derived sEVs carry out the regenerative capacities of MSCs. Human tonsil-derived MSCs (T-MSCs) are reported as a novel source of MSCs, but their effects on liver fibrosis remain unclear. In the present study, we investigated the effects of T-MSC-derived sEVs on liver fibrosis. The expression of profibrotic genes decreased in human primary hepatic stellate cells (pHSCs) co-cultured with T-MSCs. Treatment of T-MSC-sEVs inactivated human and mouse pHSCs. Administration of T-MSC-sEVs ameliorated hepatic injuries and fibrosis in chronically damaged liver induced by carbon tetrachloride (CCl4). miR-486-5p highly enriched in T-MSC-sEVs targeting the hedgehog receptor, smoothened (Smo), was upregulated, whereas Smo and Gli2, the hedgehog target gene, were downregulated in pHSCs and liver tissues treated with T-MSC-sEVs or miR-486-5p mimic, indicating that sEV-miR-486 inactivates HSCs by suppressing hedgehog signaling. Our results showed that T-MSCs attenuate HSC activation and liver fibrosis by delivering sEVs, and miR-486 in the sEVs inactivates hedgehog signaling, suggesting that T-MSCs and their sEVs are novel anti-fibrotic therapeutics for treating chronic liver disease.

Blood-Stage Plasmodium Berghei ANKA Infection Promotes Hepatic Fibrosis by Enhancing Hedgehog Signaling in Mice.

BACKGROUND/AIMS: Malaria is the most deadly parasitic infection in the world, resulting in damage to various organs, including the liver, of the infected organism; however, the mechanism causing this damage in the liver remains unclear. Liver fibrosis, a major characteristic of liver diseases, occurs in response to liver injury and is regulated by a complex network of signaling pathways. Hedgehog (Hh) signaling orchestrates a number of hepatic responses including hepatic fibrogenesis. Therefore, we investigated whether Hh signaling influenced the liver's response to malarial infection. METHODS: Eight-week-old male C57BL/6 mice inoculated with blood containing Plasmodium berghei ANKA (PbA)-infected erythrocytes were sacrificed when the level of parasitemia in the blood reached 10% or 30%, and the livers were collected for biochemical analysis. Liver responses to PbA infection were examined by hematoxylin and eosin staining, real-time polymerase chain reaction, immunohistochemistry and western blot. RESULTS: Severe hepatic injury, such as ballooned hepatocytes, sinusoidal dilatation, and infiltrated leukocytes, was evident in the livers of the malaria-infected mice. Hypoxia was also induced in 30% parasitemia group. With the accumulation of Kupffer cells, inflammation markers, TNF-α, interleukin-1ß, and chemokine (C-X-C motif) ligand 1, were significantly upregulated in the infected group compared with the control group. Expression of fibrotic markers, including transforming growth factor-ß, α-smooth muscle actin (α-SMA), collagen 1a1, thymosin ß4, and vimentin, were significantly higher in the infected groups than in the control group. With increased collagen deposition, hepatic stellate cells expressing α-SMA accumulated in the liver of the PbA-infected mice, whereas those cells were rarely detected in the livers of the control mice. The levels of Hh signaling and Yes-associated protein (YAP), two key regulators for hepatic fibrogenesis, were significantly elevated in the infected groups compared with the control group. Treatment of mice with Hh inhibitor, GDC-0449, reduced hepatic inflammation and fibrogenesis with Hh suppression in PbA-infected mice. CONCLUSION: Our results demonstrate that HSCs are activated in and Hh and YAP signaling are associated with this process, contributing to increased hepatic fibrosis in malaria-infected livers.

Efficient and reproducible generation of human induced pluripotent stem cell-derived expandable liver organoids for disease modeling.

Genetic liver disease modeling is difficult because it is challenging to access patient tissue samples and to develop practical and relevant model systems. Previously, we developed novel proliferative and functional liver organoids from pluripotent stem cells; however, the protocol requires improvement for standardization and reproducible mass production. Here, we improved the method such that it is suitable for scalable expansion and relatively homogenous production, resulting in an efficient and reproducible process. Moreover, three medium components critical for long-term expansion were defined. Detailed transcriptome analysis revealed that fibroblast growth factor signaling, the essential pathway for hepatocyte proliferation during liver regeneration, was mainly enriched in proliferative liver organoids. Short hairpin RNA-mediated knockdown of FGFR4 impaired the generation and proliferation of organoids. Finally, glycogen storage disease type Ia (GSD1a) patient-specific liver organoids were efficiently and reproducibly generated using the new protocol. They well maintained disease-specific phenotypes such as higher lipid and glycogen accumulation in the liver organoids and lactate secretion into the medium consistent with the main pathologic characteristics of patients with GSD1a. Therefore, our newly established liver organoid platform can provide scalable and practical personalized disease models and help to find new therapies for incurable liver diseases including genetic liver diseases.

Advances in liver organoids: model systems for liver disease.

Reliable in vitro models with human-derived cells that recapitulate in vivo-like physiologies are required for drug discovery and development to reduce the gap between the results of cell-based drug testing, animal testing, and human clinical trials. Liver organoid models have emerged as novel tools for hepatotoxicity evaluation, liver disease modeling, and drug screening. Liver organoids can be generated from biopsies of liver tissues or pluripotent stem cells and can be applied to various liver diseases, including metabolic associated fatty liver disease, infectious liver disease, genetic liver disease, and liver cancer. This review focuses on recent studies on organoids to model human liver diseases and discusses the advantages and limitations of current liver organoids for translational applications.

Generation of An Induced Pluripotent Stem Cell Line from Human Liver Fibroblasts from A Patient with Combined Hepatocellular-Cholangiocarcinoma.

Objective: Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare type of primary liver cancer with characteristics of both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). The pathogenesis of cHCCCC is poorly understood due to a shortage of suitable in vitro models. Due to scarce availability of human liver tissue, induced pluripotent stem cells (iPSCs) are a useful alternative source to produce renewable liver cells. For use in the development of liver pathology models, here we successfully developed and evaluated iPSCs from liver fibroblasts of a patient with cHCC-CC. Materials and Methods: In this experimental study, human liver fibroblasts (HLFs) were obtained from the liver biopsy of a 69-year-old male patient with cHCC-CC and transduced with a retroviral cocktail that included four factors - OCT4, SOX2, KLF4, and c-MYC (OSKM). Pluripotency of the iPSCs was determined by alkaline phosphatase (AP) staining, quantitative real-time polymerase chain reaction (PCR), and immunofluorescence. We induced in vitro embryoid body (EB) formation and performed an in vivo teratoma assay to confirm their differentiation capacity into the three germ layers. Results: HLF iPSCs derived from the cHCC-CC patient displayed typical iPSC-like morphology and pluripotency marker expression. The proficiency of the iPSCs to differentiate into three germ layers was assessed both in vitro and in vivo. Compared to normal control iPSCs, differentiated HLF iPSCs showed increased expressions of HCC markers alpha-fetoprotein (AFP) and Dickkopf-1 (DKK1) and the CC marker cytokeratin 7 (CK7), and a decreased expression of the CC tumour suppressor SRY-related HMG-box 17 (SOX17). Conclusion: We established HLF iPSCs using liver fibroblasts from a patient with cHCC-CC for the first time. The HLF iPSCs maintained marker expression in the patient when differentiated into EBs. Therefore, HLF iPSCs may be a sustainable cell source for modelling cHCC-CC and beneficial for understanding liver cancer pathology and developing therapies for cHCC-CC treatment.

Generation of human induced pluripotent stem cell line, KRIBBi003-A, from urinary cells of a patient with glycogen storage disease type IXa.

Glycogen storage disease type IXa (GSD IXa) is a rare genetic disorder characterized by phosphorylase kinase (PhK) deficiency, which leads to excessive glycogen accumulation in the liver. Urinary cells (UCs) were isolated from a GSD IXa patient and reprogrammed into induced pluripotent stem cells (iPSCs) using Sendai virus. The established iPSC line, KRIBBi003-A, exhibited pluripotency marker expression and a normal karyotype. The differentiation capacity of the cell line was confirmed by the differentiation of the three germ layers in vitro. The established iPSC line is a potential useful resource for disease modeling of GSD IXa.