Liver Parenchymal Cells Research Articles

Methionine restriction reduced growth performance and exacerbated lipid deposition in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) under high-lipid diets by suppressing the lipid degradation pathways with the single-cell RNA-seq analysis

The experiment mainly focused on the liver of the hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) with low methionine levels by single-cell RNA-seq under high-lipid diets. Both weight gain rate (WGR) and specific growth rate (SGR) in the MR group were obviously lower than the C group, and the intraperitoneal fat (IPF) in the MR group was obviously enhanced than HL and C groups, which led to more visible growth inhibition and lipid deposition. By using the scRNA-seq analysis, nine cell types were classified as: liver parenchymal cells, erythrocytes, hepatic stellate cells, cholangiocytes, macrophages, T cells, epidermal cells, eosinophil and fibroblasts. Lipid and carbohydrate metabolisms were mainly enriched in liver parenchymal cells. The lipid degradation pathways were obviously inhibited in the MR group, such as cholesterol degradation pathway. The lipid degradation genes were obviously decreased in the MR group. In conclusion, methionine restriction might suppress the lipid degradation pathways in liver parenchymal cells, led to obvious lipid deposition.

Nonalcoholic fatty liver disease worsens cardiac repair after myocardial infarction

Abstract Background There is a strong epidemiological link between nonalcoholic fatty liver disease (NAFLD) and ischemic heart disease such as myocardial infarction (MI). Yet, a causal relationship between liver injury and post-MI cardiac repair remains to be established. Purpose NAFLD impairs post-MI myocardial repair processes. In particular, we hypothesized that the pathological liver could transmit deleterious signals shaping the inflammatory reaction in the infarcted milieu. Methods To characterize post-MI cardiac function and remodeling in three mouse models of liver damage mimicking different stages of NAFLD without cardiovascular (CV) risk factors : i) choline-deficient, L-amino-acid-defined, high fat diet (CDA-HFD) causing severe non-alcoholic steatohepatitis; ii) NEMOLPC-KO mice deficient for NF-κB in liver parenchymal cells, exhibiting liver inflammation and fibrosis, but mild steatosis; and ATGLLPC-KO animals deficient for Adipose Triglyceride Lipase in liver parenchymal cells displaying strong steatosis. Results In our three experimental models, liver damages were characterized by inflammation, steatosis and fibrosis but were not associated with metabolic syndrome. More interestingly, left ventricular ejection fraction were reduced by 1.2-fold, 1.3-fold and 1.3-fold in CDA-HFD, NEMOLPC-KO and ATGLLPC-KO male and female mice, respectively when compared to their respective controls, at 35 days post-MI (n=12-25 per group). NAFLD-induced cardiac dysfunction was not associated with worsen cardiac remodeling as infarct size, fibrosis and vascular density were not significantly affected. On the same note, flow cytometry experiments, at 7- and 14-days post-MI, showed no changes in the number or type of inflammatory cells, particularly that of cardiac resident macrophages, in CDAHFD, ATGLLPC-KO and NEMOLPC-KO mice. We next hypothesized that reduced left ventricular function could be induced by altered cardiomyocyte contractility. To corroborate this hypothesis, we isolated cardiomyocytes from hearts of infarcted mice with or without NAFLD and assessed cell contractility using IonOptix technology. Our preliminary results, in the CDAHFD model, showed that there was a reduction in contraction amplitude, defining by the ratio of the difference in sarcomere length during contraction/relaxation to the sarcomere length at the time of relaxation. The speed of contraction and relaxation were also decreased in CDAHFD mice compared with control animals. Conclusions NAFLD favors cardiac dysfunction post-MI. We now aim to identify molecular and cellular entities participating to such pathogenic dialogue between the dysfunctional liver and the infarcted heart.

Physiological liver microtissue 384-well microplate system for preclinical hepatotoxicity assessment of therapeutic small molecule drugs.

Hepatotoxicity can lead to the discontinuation of approved or investigational drugs. The evaluation of the potential hepatoxicity of drugs in development is challenging because current models assessing this adverse effect are not always predictive of the outcome in human beings. Cell lines are routinely used for early hepatotoxicity screening, but to improve the detection of potential hepatotoxicity, in vitro models that better reflect liver morphology and function are needed. One such promising model is human liver microtissues. These are spheroids made of primary human parenchymal and nonparenchymal liver cells, which are amenable to high throughput screening. To test the predictivity of this model, the cytotoxicity of 152 FDA (US Food & Drug Administration)-approved small molecule drugs was measured as per changes in ATP content in human liver microtissues incubated in 384-well microplates. The results were analyzed with respect to drug label information, drug-induced liver injury (DILI) concern class, and drug class. The threshold IC50ATP-to-Cmax ratio of 176 was used to discriminate between safe and hepatotoxic drugs. "vMost-DILI-concern" drugs were detected with a sensitivity of 72% and a specificity of 89%, and "vMost-DILI-concern" drugs affecting the nervous system were detected with a sensitivity of 92% and a specificity of 91%. The robustness and relevance of this evaluation were assessed using a 5-fold cross-validation. The good predictivity, together with the in vivo-like morphology of the liver microtissues and scalability to a 384-well microplate, makes this method a promising and practical in vitro alternative to 2D cell line cultures for the early hepatotoxicity screening of drug candidates.

Dynamic Liver Chip Based on Well-Coupled Microfluidics: An Accurate NASH Model for Drug Evaluation.

The convenient liver model in vitro recapitulating the hepatic functions, metabolism, and even steatohepatitis to perform the accurate drug evaluation is still challenging because of the unattainable hominine physiological microenvironment in vitro. Here, the progressed stages of nonalcoholic steatohepatitis (NASH) disease were precisely modeled to accurately evaluate the performance of antilipemic based on the dynamic liver chip adopting the well-coupled microfluidics, which well recapitulated the normal and steatohepatitis of liver in vitro. In brief, the mild nutrient flow and sufficient oxygen supply for parenchymal liver cells could be well supplied through the endothelial cells layer that mimicked the real physiological barrier of endothelium, while the loading of drugs might be obtained by directly adding drug into the running nutrient flow to mimic the intravenously administrable. The progressed degree of steatohepatitis could be directly reflected by the amount of intramyocellular lipid content (IMLC) of the HepG2 cell hepatocyte layer in wells that were induced by different concentrations of free fatty acids (FFA). To prove the concept of the liver chip in drug evaluation, an accurate assessment of the performance of firsocostat, the acetyl-CoA carboxylase (ACC) inhibitor of hepatic mitochondria of hepatocytes, was carried out. The subtle time dependence of firsocostat treatment to different progressed stages of NASH was clearly figured out. Therefore, we prospect the liver chip that adopted well-coupled microfluidics could be an accurate and standard liver model in vitro to carry out the antilipemic evaluation and screening, which significantly enlightens the drug evaluation by liver on chip in vitro.

Correlation between Kupffer Cell Infiltration and Liver Parenchymal Cell Damages in Immunosuppressed Drugs-Induced Rats

The liver is the largest organ in the body, composed of both parenchymal and non-parenchymal cells. Chemical substances and various drugs can induce liver injury and involve Kupffer cells which are non-parenchymal cells that release biologically active substances, promoting pathological processes. This study aimed to evaluate the correlation between the number of Kupffer cells and liver parenchymal cell damages in immunosuppressed, drug-induced rats. The study was conducted from July to December 2019 at the Oral Biology Laboratory of the Faculty of Dentistry and the Biochemical Laboratory of the Faculty of Medicine at Universitas Hang Tuah Surabaya. Twelve healthy male Wistar rats were divided into two groups: Healthy (H) and Immunosuppressed Drug-Induced (ID) groups. Immunosuppression was induced using dexamethasone (0.5 mg/day/rat), administered orally for 14 days, combined with tetracycline (1%/day/rat). Liver samples from all rats were examined for Kupffer cell count and parenchymal cell damages were assessed using a light microscope with 400x magnification. Results revealed a significant difference in the number of Kupffer cells and liver parenchymal cell damages between the H and ID groups (p<0.05). Pearson correlation analysis indicated a significant correlation between Kupffer cell number and parenchymal cell damages (p=0.000). Continuous administration of immunosuppressive drugs may activate Kupffer cells, leading to damage of liver parenchymal cells. In conclusion, the infiltration of Kupffer cells is associated with liver parenchymal cell damages, mediated by various factors in the immunosuppressed drug-induced rat model.

Single-cell RNA sequencing reveals reduced intercellular adhesion molecule crosstalk between activated hepatic stellate cells and neutrophils alleviating liver fibrosis in hepatitis B virus transgenic mice post menstrual blood-derived mesenchymal stem cell transplantation.

Liver fibrosis can cause hepatitis B virus (HBV)-associated hepatocellular carcinoma. Menstrual blood-derived mesenchymal stem cells (MenSCs) can ameliorate liver fibrosis through paracrine. Single-cell RNA sequencing (scRNA-seq) may be used to explore the roadmap of activated hepatic stellate cell (aHSC) inactivation to target liver fibrosis. This study established HBV transgenic (HBV-Tg) mouse model of carbon tetrachloride (CCl4)-induced liver fibrosis and demonstrated that MenSCs migrated to the injured liver to improve serological indices and reduce fibrotic accumulation. RNA-bulk analysis revealed that MenSCs mediated extracellular matrix accumulation and cell adhesion. Liver parenchymal cells and nonparenchymal cells were identified by scRNA-seq in the control, CCl4, and MenSC groups, revealing the heterogeneity of fibroblasts/HSCs. A CellChat analysis revealed that diminished intercellular adhesion molecule (ICAM) signaling is vital for MenSC therapy. Specifically, Icam1 in aHSCs acted on Itgal/Itgb2 and Itgam/Itgb2 in neutrophils, causing decreased adhesion. The expression of Itgal, Itgam, and Itgb2 was higher in CCl4 group than in the control group and decreased after MenSC therapy in neutrophil clusters. The Lcn2, Pglyrp1, Wfdc21, and Mmp8 had high expression and may be potential targets in neutrophils. This study highlights interacting cells, corresponding molecules, and underlying targets for MenSCs in treating HBV-associated liver fibrosis.

From Drug Discovery to Drug Approval: A Comprehensive Review of the Pharmacogenomics Status Quo with a Special Focus on Egypt.

Pharmacogenomics (PGx) is the hope for the full optimization of drug therapy while minimizing the accompanying adverse drug events that cost billions of dollars annually. Since years before the century, it has been known that inter-individual variations contribute to differences in specific drug responses. It is the bridge to what is well-known today as "personalized medicine". Addressing the drug's pharmacokinetics and pharmacodynamics is one of the features of this science, owing to patient characteristics that vary on so many occasions. Mainly in the liver parenchymal cells, intricate interactions between the drug molecules and enzymes family of so-called "Cytochrome P450" occur which hugely affects how the body will react to the drug in terms of metabolism, efficacy, and safety. Single nucleotide polymorphisms, once validated for a transparent and credible clinical utility, can be used to guide and ensure the succession of the pharmacotherapy plan. Novel tools of pharmacoeconomics science are utilized extensively to assess cost-effective pharmacogenes preceding the translation to the bedside. Drug development and discovery incorporate a drug-gene perspective and save more resources. Regulations and laws shaping the clinical PGx practice can be misconceived; however, these pre-/post approval processes ensure the product's safety and efficacy. National and international regulatory agencies seek guidance on maintaining conduct in PGx practice. In this patient-centric era, social and legal considerations manifest in a way that makes them unavoidable, involving patients and other stakeholders in a deliberate journey toward utmost patient well-being. In this comprehensive review, we contemporarily addressed the scientific leaps in PGx, along with various challenges that face the proper implementation of personalized medicine in Egypt. These informative insights were drawn to serve what the Egyptian population, in particular, would benefit from in terms of knowledge and know-how while maintaining the latest global trends. Moreover, this review is the first to discuss various modalities and challenges faced in Egypt regarding PGx, which we believe could be used as a pilot piece of literature for future studies locally, regionally, and internationally.

The influence of “Butaintersyl” on the antioxidant status of rats under conditions of toxic damage caused by tetrachloromethane

Tetrachloromethane (CCl4) is a toxic chemical substance known in scientific research as a model for studying the damage of parenchymal liver cells. The mechanisms of CCl4 toxicity include the activation of lipid peroxidation processes, the intensive formation of free radicals, and, as a result, the disruption of the pro-/antioxidant balance. This work aimed to study the effect of the liposomal drug “Butaintersyl” on the activity of the glutathione antioxidant protection system and the intensity of lipid peroxidation processes in the blood of rats under conditions of toxic damage caused by tetrachloromethane. The studies were conducted on white sexually mature young Wistar rats weighing 180–200 g, kept in the institute's vivarium of the State Scientific Research Control Institute of Veterinary Drugs and Feed Additives. In the blood of the rats, changes in the activity of glutathione peroxidase and the level of reduced glutathione were studied, as well as the levels of lipid peroxidation products: lipid hydroperoxides and TBA-active products. The development of oxidative stress in the first experimental group of rats was accompanied by the suppression of the glutathione antioxidant protection system, as evidenced by a decrease in blood glutathione peroxidase activity and the level of reduced glutathione. At the same time, the intoxicated animals showed an increase in lipid peroxidation processes, namely an increase in the blood levels of lipid hydroperoxides and TBA-active products throughout the study period. The studies showed that in cases of poisoning of various origins, it is advisable to use drugs that reduce the formation of reactive oxygen species and lipoperoxidation processes, exhibit antioxidant effects, and stabilize cell membranes. A special place among such drugs is occupied by the liposomal drug “Butaintersyl”. This drug ensures the stabilization of biological membranes. The liposomal drug “Butaintersyl” contributed to suppressing lipid peroxidation processes and activating the antioxidant protection system, as evidenced by the high content of reduced glutathione and glutathione peroxidase activity. Due to its antioxidant properties, the drug positively affected the activity of membrane-dependent enzymes. It reduced the level of endogenous intoxication, allowing it to be recommended for inclusion in prevention schemes for toxic liver damage caused by chemical compounds.

CGAS suppresses hepatocellular carcinoma independent of its cGAMP synthase activity.

Cyclic GMP-AMP synthase (cGAS) is a key innate immune sensor that recognizes cytosolic DNA to induce immune responses against invading pathogens. The role of cGAS is conventionally recognized as a nucleotidyltransferase to catalyze the synthesis of cGAMP upon recognition of cytosolic DNA, which leads to the activation of STING and production of type I/III interferon to fight against the pathogen. However, given that hepatocytes are lack of functional STING expression, it is intriguing to define the role of cGAS in hepatocellular carcinoma (HCC), the liver parenchymal cells derived malignancy. In this study, we revealed that cGAS was significantly downregulated in clinical HCC tissues, and its dysregulation contributed to the progression of HCC. We further identified cGAS as an immune tyrosine inhibitory motif (ITIM) containing protein, and demonstrated that cGAS inhibited the progression of HCC and increased the response of HCC to sorafenib treatment by suppressing PI3K/AKT/mTORC1 pathway in cellular and animal models. Mechanistically, cGAS recruits SH2-containing tyrosine phosphatase 1 (SHP1) via ITIM, and dephosphorylates p85 in phosphatidylinositol 3-kinase (PI3K), which leads to the suppression of AKT-mTORC1 pathway. Thus, cGAS is identified as a novel tumor suppressor in HCC via its function independent of its conventional role as cGAMP synthase, which indicates a novel therapeutic strategy for advanced HCC by modulating cGAS signaling.

Abstract LB121: Endothelial cells mediated paracrine signaling alters immune cell modulators on colorectal cancer cells

Abstract Background: Metastatic colorectal cancer (mCRC) is the second leading cause of cancer related deaths in the US. Various factors in the tumor microenvironment (TME) play significant roles in progression of CRC tumors and their response to various therapies. Previous studies from our laboratory and other groups have demonstrated that blood vessels and their constituent endothelial cells (ECs) exert strong effects on CRC cells by altering stemness, enhancing drug resistance, and increasing cell survival. Although ECs have also been shown to affect immune cell function or alter the tumor immune environment by direct or indirect mechanisms, their role in altering immune-modulating effectors on tumor cells, especially CRC cells, are poorly understood. Thus, elucidating the role of ECs in regulating immune-modulators in CRC cells and understanding the underlying mechanisms by which this occurs will provide important insights into the role of ECs on altering the immune-microenvironment of CRC tumors that likely affects tumor progression and, possibly, response to immunotherapies. Methods: A panel of CRC cells lines were exposed to conditioned media (CM) from CRC or multiple primary or immortalized liver parenchymal endothelial cells (LPECs), and alterations in some of the known immune-inhibitory ligands were measured by western blotting or flow cytometry. Molecular size-based fractionation of CRC-CM or LPEC-CM were performed and various sized fractions were utilized to detect fractions harboring inducers of immune-inhibitory ligands. Mass spectrometry was performed to identify possible factors in LPEC-CM. Western blotting of CRC cell lysates was performed to identify possible signaling changes following LPEC-CM treatment. Results: Our studies demonstrated that ECs were more efficient in inducing PD-L1 expression in CRC cells compared to other cell types present in the CRC tumor microenvironment. LPEC-CM induced PD-L1 expression in multiple CRC cells regardless of their genetic mutations or MSI-H/MSS status. Initial studies indicate that LPEC-CM can also enhance MHC-1 expression in CRC cells. Size-fractionation studies indicate that inducer/s of PD-L1 expression are present in a fraction >100kDa. Mass-spectrometry of this fraction has identified prospective candidates that can possibly induce PD-L1 on CRC cells. CRC cells treated with LPEC-CM led to enhanced levels of pSTAT3, a known PD-L1 transcription factor. Conclusions: Our studies, for the first time, demonstrate that ECs, through paracrine signaling, can educate CRC cells to overexpress immune-modulatory ligands. Further studies are being conducted to elucidate the molecular factors involved in these processes. These studies not only shed light on the complex role played by ECs in modulating the TME, but also warrants further investigations into the effects of these changes in CRC tumor progression and responses to therapies. Citation Format: FanFan, Lee M. Ellis, Rajat Bhattacharya. Endothelial cells mediated paracrine signaling alters immune cell modulators on colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB121.

Correspondence on Letter regarding "Both liver parenchymal and non-parenchymal cells express JCAD proteins under various circumstances".

Correspondence on Letter regarding "Both liver parenchymal and non-parenchymal cells express JCAD proteins under various circumstances".

Both liver parenchymal and non-parenchymal cells express JCAD protein under various circumstances.

Both liver parenchymal and non-parenchymal cells express JCAD protein under various circumstances.

Van Gogh-like 2 is essential for the architectural patterning of the mammalian biliary tree

In the developing liver, bipotent epithelial progenitor cells undergo lineage segregation to form hepatocytes, which constitute the bulk of the liver parenchyma, and biliary epithelial cells (cholangiocytes), which comprise the bile duct (a complex tubular network that is critical for normal liver function). Notch and TGFβ signalling promote the formation of a sheet of biliary epithelial cells, the ductal plate, that organises into discontinuous tubular structures. How these structures elongate and connect to form a continuous duct remains undefined. We aimed to define the mechanisms by which the ductal plate transitions from a simple sheet of epithelial cells into a complex and connected bile duct. By combining single-cell RNA sequencing of embryonic mouse livers with genetic tools and organoid models we functionally dissected the role of planar cell polarity in duct patterning. We show that the planar cell polarity protein VANGL2 is expressed late in intrahepatic bile duct development and patterns the formation of cell-cell contacts between biliary cells. The patterning of these cell contacts regulates the normal polarisation of the actin cytoskeleton within biliary cells and loss of Vangl2 function results in the abnormal distribution of cortical actin remodelling, leading to the failure of bile duct formation. Planar cell polarity is a critical step in the post-specification sculpture of the bile duct and is essential for establishing normal tissue architecture. Like other branched tissues, such as the lung and kidney, the bile ducts use planar cell polarity signalling to coordinate cell movements; however, how these biochemical signals are linked to ductular patterning remains unclear. Here we show that the core planar cell polarity protein VANGL2 patterns how cell-cell contacts form in the mammalian bile duct and how ductular cells transmit confluent mechanical changes along the length of a duct. This work sheds light on how biological tubes are patterned across mammalian tissues (including within the liver) and will be important in how we promote ductular growth in patients where the duct is mis-patterned or poorly formed.

Cells in the liver microenvironment regulate the process of liver metastasis.

The research of liver metastasis is a developing field. The ability of tumor cells to invade the liver depends on the complicated interactions between metastatic cells and local subpopulations in the liver (including Kupffer cells, hepatic stellate cells, liver sinusoidal endothelial cells, and immune-related cells). These interactions are mainly mediated by intercellular adhesion and the release of cytokines. Cell populations in the liver microenvironment can play a dual role in the progression of liver metastasis through different mechanisms. At the same time, we can see the participation of liver parenchymal cells and nonparenchymal cells in the process of liver metastasis of different tumors. Therefore, the purpose of this article is to summarize the relationship between cellular components of liver microenvironment and metastasis and emphasize the importance of different cells in the occurrence or potential regression of liver metastasis.

Innate and adaptive immune cell interaction drives inflammasome activation and hepatocyte apoptosis in murine liver injury from immune checkpoint inhibitors

Immune checkpoints (CTLA4 & PD-1) are inhibitory pathways that block aberrant immune activity and maintain self-tolerance. Tumors co-opt these checkpoints to avoid immune destruction. Immune checkpoint inhibitors (ICIs) activate immune cells and restore their tumoricidal potential, making them highly efficacious cancer therapies. However, immunotolerant organs such as the liver depend on these tolerogenic mechanisms, and their disruption with ICI use can trigger the unintended side effect of hepatotoxicity termed immune-mediated liver injury from ICIs (ILICI). Learning how to uncouple ILICI from ICI anti-tumor activity is of paramount clinical importance. We developed a murine model to recapitulate human ILICI using CTLA4+/- mice treated with either combined anti-CTLA4 + anti-PDL1 or IgG1 + IgG2. We tested two forms of antisense oligonucleotides to knockdown caspase-3 in a total liver (parenchymal and non-parenchymal cells) or in a hepatocyte-specific manner. We also employed imaging mass cytometry (IMC), a powerful multiplex modality for immunophenotyping and cell interaction analysis in our model. ICI-treated mice had significant evidence of liver injury. We detected cleaved caspase-3 (cC3), indicating apoptosis was occurring, as well as Nod-like receptor protein 3 (NLRP3) inflammasome activation, but no necroptosis. Total liver knockdown of caspase-3 worsened liver injury, and induced further inflammasome activation, and Gasdermin-D-mediated pyroptosis. Hepatocyte-specific knockdown of caspase-3 reduced liver injury and NLRP3 inflammasome activation. IMC-generated single-cell data for 77,692 cells was used to identify 22 unique phenotypic clusters. Spatial analysis revealed that cC3+ hepatocytes had significantly closer interactions with macrophages, Kupffer cells, and NLRP3hi myeloid cells than other cell types. We also observed zones of three-way interaction between cC3+ hepatocytes, CD8 + T-cells, and macrophages. Our work is the first to identify hepatocyte apoptosis and NLRP3 inflammasome activation as drivers of ILICI. Furthermore, we report that the interplay between adaptive and innate immune cells is critical to hepatocyte apoptosis and ILICI.

Exploration of Preservation Methods for Utilizing Porcine Fetal-Organ-Derived Cells in Regenerative Medicine Research.

Human pluripotent stem cells have been employed in generating organoids, yet their immaturity compared to fetal organs and the limited induction of all constituent cell types remain challenges. Porcine fetal progenitor cells have emerged as promising candidates for co-culturing with human progenitor cells in regeneration and xenotransplantation research. This study focused on identifying proper preservation methods for porcine fetal kidneys, hearts, and livers, aiming to optimize their potential as cell sources. Extracted from fetal microminiature pigs, these organs were dissociated before and after cryopreservation-thawing, with subsequent cell quality evaluations. Kidney cells, dissociated and aggregated after vitrification in a whole-organ form, were successfully differentiated into glomeruli and tubules in vivo. In contrast, freezing hearts and livers before dissociation yielded suboptimal results. Heart cells, frozen after dissociation, exhibited pulsating heart muscle cells similar to non-frozen hearts. As for liver cells, we developed a direct tissue perfusion technique and successfully obtained highly viable liver parenchymal cells. Freezing dissociated liver cells, although inferior to their non-frozen counterparts, maintained the ability for colony formation. The findings of this study provide valuable insights into suitable preservation methods for porcine fetal cells from kidneys, hearts, and livers, contributing to the advancement of regeneration and xenotransplantation research.

Functions and Clinical Relevance of Liver-Derived Immunoglobulins.

Liver is the largest internal organ of the body with vital functions. In addition to its endocrine and exocrine activities, liver also plays a pivotal role in the immune system, including haematopoietic functions. Liver parenchymal cells, which are epithelial cells, have been found to possess innate immune functions by expressing pattern-recognition receptors (PRRs), producing complement components, and secreting cytokines. Intriguingly, in recent years, it has been discovered that liver epithelial cells also produce immunoglobulins (Igs), which have long been thought to be produced exclusively by B cells. Notably, even liver epithelial cells from B lymphocyte-deficient mice, including SCID mice and μMT mice, could also produce Igs. Compelling evidence has revealed both the physiological and pathological functions of liver-derived Igs. For instance, liver epithelial cells-derived IgM can serve as a source of natural and specific antibodies that contribute to innate immune responses, while liver-produced IgG can act as a growth factor to promote cell proliferation and survival in normal hepatocytes and hepatocarcinoma. Similar to that in B cells, the toll-like receptor 9 (TLR9)-MyD88 signaling pathway is also actively involved in promoting liver epithelial cells to secrete IgM. Liver-derived Igs could potentially serve as biomarkers, prognostic indicators, and therapeutic targets in the clinical setting, particularly for liver cancers and liver injury. Nevertheless, despite significant advances, much remains unknown about the mechanisms governing Ig transcription in liver cells, as well as the detailed functions of liver-derived Igs and their involvement in diseases and adaptive immunity. Further studies are still needed to reveal these underlying, undefined issues related to the role of liver-derived Igs in both immunity and diseases.

Gut microbiota and metabolite interface-mediated hepatic inflammation.

Immunologic and metabolic signals regulated by gut microbiota and relevant metabolites mediate bidirectional interaction between the gut and liver. Gut microbiota dysbiosis, due to diet, lifestyle, bile acids, and genetic and environmental factors, can advance the progression of chronic liver disease. Commensal gut bacteria have both pro- and anti-inflammatory effects depending on their species and relative abundance in the intestine. Components and metabolites derived from gut microbiota-diet interaction can regulate hepatic innate and adaptive immune cells, as well as liver parenchymal cells, significantly impacting liver inflammation. In this mini review, recent findings of specific bacterial species and metabolites with functions in regulating liver inflammation are first reviewed. In addition, socioeconomic and environmental factors, hormones, and genetics that shape the profile of gut microbiota and microbial metabolites and components with the function of priming or dampening liver inflammation are discussed. Finally, current clinical trials evaluating the factors that manipulate gut microbiota to treat liver inflammation and chronic liver disease are reviewed. Overall, the discussion of microbial and metabolic mediators contributing to liver inflammation will help direct our future studies on liver disease.

A pumpless liver-on-a-chip for drug hepatotoxicity analysis.

This study presents the development and validation of an innovative microfluidic liver-on-a-chip device utilizing gravity-driven perfusion for the evaluation of drug hepatotoxicity. This research involved the construction of a hydrogel-based coculture chip that integrates liver parenchymal and stellate cells within a tri-channel configuration. The assembly and operation of the liver-on-a-chip and its accompanying custom rocker were straightforward. The cells in the chip maintained high viability and continuously synthesized liver albumin over extended culture durations. Acetaminophen (APAP), a hepatic injury-inducing drug, was utilized as a positive control in hepatic toxicity assays on the chip. The liver chip exhibited hepatotoxic responses comparable to those observed in 2D models. Furthermore, in this study we evaluated the effects of two plant-derived natural compounds, aristolochic acid I (AA) and its analog aristolactam AII (AL), in both 2D cell models and the liver-on-a-chip system. AA, known for its hepatorenal toxicity, was observed to cause hepatotoxicity in both the 2D models and on the chip. The flow cytometry and mRNA sequencing results confirmed the propensity of these compounds to induce liver cell apoptosis. Notably, AL, previously considered nontoxic, provoked a significant decrease in the hepatic functionality marker albumin exclusively in the liver chip but not in 2D models, indicating the liver chip's enhanced sensitivity to toxic substances. In summary, this pumpless liver-on-a-chip is a simple yet powerful tool for drug hepatotoxicity studies.

Chromatin accessibility analysis suggested vascular induction of the biliary epithelium via the Notch signaling pathway in the human liver

The biliary epithelial cells (cholangiocytes) in the liver originate from undifferentiated liver parenchymal cells (hepatoblasts) that are located adjacent to the portal vein. This differentiation process is driven by Notch signaling, which is recognized for generating salt-and-pepper (fine-grained) patterns, in contrast to one- or two-cell layer (spatially confined) patterning in cholangiocyte differentiation. It is unclear how Notch signaling acts and localizes only in cholangiocytes. A computer simulation study suggested that low production rates of the ligands or receptors of Notch signaling are crucial for the spatially confined patterning, although biochemical examination is lacking. Here, we analyzed a publicly available single-cell ATAC-sequencing dataset from human fetal liver samples. We showed high chromatin accessibility for the ligands only in vascular cells, while that for the receptor is limited to a small population of hepatoblasts. This finding strengthens the previously proposed idea that low production rates of the ligands or receptors of Notch signaling enable vascular induction of cholangiocytes.