The pivotal role of dysregulated autophagy in the progression of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathologic syndrome characterized by excessive fat deposition in hepatocytes and a major cause of end-stage liver disease. Autophagy is a metabolic pathway responsible for degrading cytoplasmic products and damaged organelles, playing a pivotal role in maintaining the homeostasis and functionality of hepatocytes. Recent studies have shown that pharmacological intervention to activate or restore autophagy provides benefits for liver function recovery by promoting the clearance of lipid droplets (LDs) in hepatocytes, decreasing the production of pro-inflammatory factors, and inhibiting activated hepatic stellate cells (HSCs), thus improving liver fibrosis and slowing down the progression of NAFLD. This article summarizes the physiological process of autophagy, elucidates the close relationship between NAFLD and autophagy, and discusses the effects of drugs on autophagy and signaling pathways from the perspectives of hepatocytes, kupffer cells (KCs), and HSCs to provide assistance in the clinical management of NAFLD.

Cav3.2 deletion attenuates nonalcoholic fatty liver disease in mice.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the main cause of liver cirrhosis and hepatocellular carcinoma. Cav3.2 is a T-type calcium channel that is widely present in tissues throughout the body and plays a vital role in energy and metabolic balance. However, the effects of Cav3.2 on the NFALD remain unclear. Here, we investigated the role of Cav3.2 channel in the development and progression of NAFLD. After 16 weeks on a high-fat diets (HFD), Cav3.2 knockout (Cav3.2 KO) improved hepatic steatosis, liver injury and metabolic syndrome in an NAFLD mouse model. We provided evidence that Cav3.2 KO inhibited HFD-induced hepatic oxidative stress, inflammation and hepatocyte apoptosis. In addition, Cav3.2 KO also attenuated hepatic lipid accumulation, oxidative stress, inflammation and hepatocyte apoptosis in palmitic acid/oleic acid (PAOA)-treated primary hepatocytes. These results suggest that therapeutic approaches targeting Cav3.2 provide effective approaches for treating NAFLD.

Adhesion of pancreatic tumor cell clusters by desmosomal molecules enhances early liver metastases formation.

Desmosomes are intercellular adhesion complexes providing mechanical coupling and tissue integrity. Previously, a correlation of desmosomal molecule expression with invasion and metastasis formation in several tumor entities was described together with a relevance for circulating tumor cell cluster formation. Here, we investigated the contribution of the desmosomal core adhesion molecule desmoglein-2 (DSG2) to the initial steps of liver metastasis formation by pancreatic cancer cells using a novel ex vivo liver perfusion mouse model. We applied the pancreatic ductal adenocarcinoma cell line AsPC-1 with and without a knockout (KO) of DSG2 and generated mouse lines with a hepatocyte-specific KO of the known interacting partners of DSG2 (DSG2 and desmocollin-2). Liver perfusion with DSG2 KO AsPC-1 cells led to smaller circulating cell clusters and a reduced number of cells adhering to murine livers compared to control cells. While this was independent of the expression levels of desmosomal adhesion molecules in hepatocytes, we show that increased cluster size of cancer cells, which correlates with stronger cell-cell adhesion and expression of desmosomal molecules, is a major factor contributing to the early phase of metastatic spreading. In conclusion, impaired desmosomal adhesion results in reduced circulating cell cluster size, which is relevant for seeding and attachment of metastatic cells to the liver.

Enhanced In Vitro Recapitulation of In Vivo Liver Regeneration by Co-Culturing Hepatocyte Organoids with Adipose-Derived Mesenchymal Stem Cells, Alleviating Steatosis and Apoptosis in Acute Alcoholic Liver Injury.

Hepatocyte organoids (HOs) have superior hepatic functions to cholangiocyte-derived organoids but suffer from shorter lifespans. To counteract this, we co-cultured pig HOs with adipose-derived mesenchymal stem cells (A-MSCs) and performed transcriptome analysis. The results revealed that A-MSCs enhanced the collagen synthesis pathways, which are crucial for maintaining the three-dimensional structure and extracellular matrix synthesis of the organoids. A-MSCs also increased the expression of liver progenitor cell markers (KRT7, SPP1, LGR5+, and TERT). To explore HOs as a liver disease model, we exposed them to alcohol to create an alcoholic liver injury (ALI) model. The co-culture of HOs with A-MSCs inhibited the apoptosis of hepatocytes and reduced lipid accumulation of HOs. Furthermore, varying ethanol concentrations (0-400 mM) and single-versus-daily exposure to HOs showed that daily exposure significantly increased the level of PLIN2, a lipid storage marker, while decreasing CYP2E1 and increasing CYP1A2 levels, suggesting that CYP1A2 may play a critical role in alcohol detoxification during short-term exposure. Moreover, daily alcohol exposure led to excessive lipid accumulation and nuclear fragmentation in HOs cultured alone. These findings indicate that HOs mimic in vivo liver regeneration, establishing them as a valuable model for studying liver diseases, such as ALI.

Histopathological impact of SARS-CoV-2 on the liver: Cellular damage and long-term complications.

Coronavirus disease 2019 (COVID-19), caused by the highly pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily impacts the respiratory tract and can lead to severe outcomes such as acute respiratory distress syndrome, multiple organ failure, and death. Despite extensive studies on the pathogenicity of SARS-CoV-2, its impact on the hepatobiliary system remains unclear. While liver injury is commonly indicated by reduced albumin and elevated bilirubin and transaminase levels, the exact source of this damage is not fully understood. Proposed mechanisms for injury include direct cytotoxicity, collateral damage from inflammation, drug-induced liver injury, and ischemia/hypoxia. However, evidence often relies on blood tests with liver enzyme abnormalities. In this comprehensive review, we focused solely on the different histopathological manifestations of liver injury in COVID-19 patients, drawing from liver biopsies, complete autopsies, and in vitro liver analyses. We present evidence of the direct impact of SARS-CoV-2 on the liver, substantiated by in vitro observations of viral entry mechanisms and the actual presence of viral particles in liver samples resulting in a variety of cellular changes, including mitochondrial swelling, endoplasmic reticulum dilatation, and hepatocyte apoptosis. Additionally, we describe the diverse liver pathology observed during COVID-19 infection, encompassing necrosis, steatosis, cholestasis, and lobular inflammation. We also discuss the emergence of long-term complications, notably COVID-19-related secondary sclerosing cholangitis. Recognizing the histopathological liver changes occurring during COVID-19 infection is pivotal for improving patient recovery and guiding decision-making.

NUAK1 promotes metabolic dysfunction-associated steatohepatitis progression by activating Caspase 6-driven pyroptosis and inflammation.

BACKGROUND: lNUAK1 is strongly associated with organ fibrosis, but its causal mechanism for modulating lipid metabolism and hepatic inflammation underlying MASH has not been fully clarified. METHOD: In our study, human liver tissues from patients with MASH and control subjects were obtained to evaluate NUAK1 expression. MASH models were established using C57BL/6 mice. Liver damage and molecular mechanisms of the NUAK1-Caspase 6 signaling were tested in vivo and in vitro. RESULTS: In the clinical arm, NUAK1 expression was upregulated in liver samples from patients with MASH. Moreover, increased NUAK1 was detected in mouse MASH models. NUAK1 inhibition ameliorated steatohepatitis development in MASH mice accompanied by the downregulation of hepatic steatosis and fibrosis. Intriguingly, NUAK1 was found to facilitate Caspase 6 activation and trigger pyroptosis in MASH-stressed livers. Disruption of hepatocytes Caspase 6 decreased MASH-induced liver inflammation with upregulated TAK1 but diminished RIPK1. Moreover, we found that NUAK1/Caspase 6 axis inhibition could accelerate the interaction between TAK1 and RIPK1, which in turn led to the degradation of RIPK1. CONCLUSIONS: In summary, our study elucidates that NUAK1-Caspase 6 signaling controls inflammation activation in MASH through the interaction between TAK1 and RIPK1, which is crucial for controlling pyroptosis and promoting the progression of MASH.

Hepatocyte-derived FGL1 accelerates liver metastasis and tumor growth by inhibiting CD8+ T and NK cells.

Fibrinogen-like protein 1 (FGL1) contributes to the proliferation and metabolism of hepatocytes; however, as a major ligand of the immune checkpoint, its role in the liver regional immune microenvironment is poorly understood. Hepatocytes specifically and highly expressed FGL1 under normal physiological conditions. Increases in hepatic CD8+ T and NK cell numbers and functions were found in Fgl1-deficient (Fgl1-/-) mice, but not in the spleen or lymph node, similar to findings in anti-FGL1 mAb-treated wild-type mice. Furthermore, Fgl1 deficiency or anti-FGL1 mAb blockade restrained liver metastasis and slowed the growth of orthotopic tumors, with significantly prolonged survival of tumor-bearing mice. Tumor-infiltrating hepatic CD8+ T and NK cells upregulated the expression of lymphocyte activation gene-3 (LAG-3) and exhibited stronger antitumor activities after anti-FGL1 treatment. The antitumor efficacy of FGL1 blockade depended on cytotoxic T lymphocytes and NK cells, demonstrated by using a cell-deficient mouse model and cell transfer in vivo. In vitro, FGL1 directly inhibited hepatic T and NK cells related to the receptor LAG-3. In conclusion, hepatocyte-derived FGL1 played critical immunoregulatory roles in the liver and contributed to liver metastasis and tumor growth by inhibiting CD8+ T and NK cell functions via the receptor LAG-3, providing a new strategy for liver cancer immunotherapy.

[Characteristics of liver volume and pathological changes with different stages of liver fibrosis in chronic liver disease].

Objective: To measure the overall and lobulated volume of the liver with different degrees of liver fibrosis and to further observe pathological changes such as liver microvasculature, hepatocyte apoptosis, and regeneration in order to understand the macroscopic volume changes of the liver during liver fibrosis and its relationship with liver tissue microscopic pathology in patients with chronic liver disease. Methods: 53 patients with chronic hepatitis B, alcoholic fatty liver disease, autoimmune liver disease, nonalcoholic fatty liver disease, and drug-induced chronic liver disease who underwent both liver biopsy tissue and abdominal magnetic resonance imaging were collected. Patients were divided into early (F1-2), middle (F3-4), and late (F5-6) in accordance with the Ishak fibrosis stage and Masson stain. The liver and spleen volumes were measured using ITK-SNAP software. CD31 immunohistochemical staining was used to reflect intrahepatic angiogenesis. Ki67 and HNF-4α multiplex immunohistochemical staining were used to reflect hepatocyte regeneration. GS staining was used to determine parenchymal extinction lesions. TUNEL staining was used to observe hepatocyte apoptosis. Spearman correlation analysis was used to analyze the relationship between liver volume changes and liver histopathological changes. Results: As liver fibrosis progressed, the total liver volume and right lobe liver volume gradually decreased (P<0.05), while the spleen volume gradually increased (P<0.05). The expression of CD31 and GS gradually increased (P<0.05), and the expression of Ki67 first increased and then decreased (P<0.05). The positivity rate of CD31 was negatively correlated with the right lobe liver volume (r=-0.609, P<0.001) and the total liver volume (r=-0.363, P=0.017). The positivity rate of Ki67 was positively correlated with the right lobe liver volume (r=0.423, P=0.018), while the positivity rate of apoptotic cells was significantly negatively correlated with the total liver volume (r=-0.860, P<0.001). The positivity rate of GS was negatively correlated with the right lobe liver volume (r=-0.440, P=0.002), and the number of PELs was negatively correlated with RV (r=-0.476, P=0.013). The CD31 positive staining area was negatively correlated with the Ki67 positive staining area(r=-0.511, P=0.009). Conclusion: As liver fibrosis progresses, patients with chronic liver disease have a depletion in total liver volume and right lobe liver volume, and this is mainly in correlation with fewer liver cells and liver tissue microvasculature disorders.

Neddylation inhibition prevents acetaminophen-induced liver damage by enhancing the anabolic cardiolipin pathway.

Drug-induced liver injury (DILI) is a significant cause of acute liver failure (ALF) and liver transplantation in the Western world. Acetaminophen (APAP) overdose is a main contributor of DILI, leading to hepatocyte cell death through necrosis. Here, we identified that neddylation, an essential post-translational modification involved in the mitochondria function, was upregulated in liver biopsies from patients with APAP-induced liver injury (AILI) and in mice treated with an APAP overdose. MLN4924, an inhibitor of the neuronal precursor cell-expressed developmentally downregulated protein 8 (NEDD8)-activating enzyme (NAE-1), ameliorated necrosis and boosted liver regeneration in AILI. To understand how neddylation interferes in AILI, whole-body biotinylated NEDD8 (bioNEDD8) and ubiquitin (bioUB) transgenic mice were investigated under APAP overdose with and without MLN4924. The cytidine diphosphate diacylglycerol (CDP-DAG) synthase TAM41, responsible for producing cardiolipin essential for mitochondrial activity, was found modulated under AILI and restored its levels by inhibiting neddylation. Understanding this ubiquitin-like crosstalk in AILI is essential for developing promising targeted inhibitors for DILI treatment.

Exosomes derived from periodontitis induce hepatic steatosis through the SCD-1/AMPK signaling pathway.

AIM: To investigate the impact of exosomes released by Porphyromonas gingivalis-Lipopolysaccharide activated THP-1 macrophages and human periodontal ligament fibroblasts on hepatocyte fat metabolism. RESULTS: The liver of rats with experimental periodontitis showed obvious steatosis and inflammation compared with control rats. The culture supernatant of macrophages and human periodontal ligament fibroblasts (hPDLFs), when stimulated with Pg-LPS, induced lipogenesis in HepG2 cells. Furthermore, the lipid-promoting effect was effectively inhibited by the addition of the exosome inhibitor GW4869. Subsequently, we isolated exosomes from cells associated with periodontitis. Exosomes released by Pg-LPS-stimulated macrophages and hPDLFs are taken up by hepatocytes, causing mRNA expression related to fat synthesis, promoting triglyceride synthesis, and aggravating NAFLD progression. Finally, two sets of exosomes were injected into mice through the tail vein. In vivo experiments have also demonstrated that periodontitis-associated exosomes promote the development of hepatic injury and steatosis, upregulate SCD-1 expression and inhibit the AMPK signaling pathway. CONCLUSIONS: In conclusion, we found that exosomes associated with periodontitis promote hepatocyte adipogenesis by increasing the expression of SCD-1 and suppressing the AMPK pathway, which indicates that close monitoring of the progression of stomatopathy associated extra-oral disorders is important and establishes a theoretical foundation for the prevention and management of fatty liver disease linked to periodontitis.

Targeting BRD4 mitigates hepatocellular lipotoxicity by suppressing the NLRP3 inflammasome activation and GSDMD-mediated hepatocyte pyroptosis.

Nod-like receptor family pyrin-containing protein 3 (NLRP3) inflammasome plays a pathologic role in metabolic dysfunction-associated steatohepatitis (MASH), but the molecular mechanism regulating the NLRP3 inflammasome activation in hepatocellular lipotoxicity remains largely unknown. Bromodomain-containing protein 4 (BRD4) has emerged as a key epigenetic reader of acetylated lysine residues in enhancer regions that control the transcription of key genes. The aim of this study is to investigate if and how BRD4 regulated the NLRP3 inflammasome activation and pyroptosis in MASH. Using the AML12 and primary mouse hepatocytes stimulated by palmitic acid (PA) as an in vitro model of hepatocellular lipotoxicity, we found that targeting BRD4 by genetic knockdown or a selective BRD4 inhibitor MS417 protected against hepatosteatosis; and this protective effect was attributed to inhibiting the activation of NLRP3 inflammasome and reducing the expression of Caspase-1, gasdermin D (GSDMD), interleukin (IL)-1ß and IL-6. Moreover, BRD4 inhibition limited the voltage-dependent anion channel-1 (VDAC1) expression and oligomerization in PA-treated AML12 hepatocytes, thereby suppressing the NLRP3 inflammasome activation. Additionally, the expression of BRD4 enhanced in MASH livers of humans. Mechanistically, BRD4 was upregulated during hepatocellular lipotoxicity that in turn modulated the active epigenetic mark H3K27ac at the promoter regions of the Vdac and Gsdmd genes, thereby enhancing the expression of VDAC and GSDMD. Altogether, our data provide novel insights into epigenetic mechanisms underlying BRD4 activating the NLRP3 inflammasome and promoting GSDMD-mediated pyroptosis in hepatocellular lipotoxicity. Thus, BRD4 might serve as a novel therapeutic target for the treatment of MASH.

GPR116 alleviates acetaminophen-induced liver injury in mice by inhibiting endoplasmic reticulum stress.

BACKGROUND: Acetaminophen (APAP) overdose is a significant contributor to drug-induced liver injury worldwide. G-protein-coupled receptor 116 (GPR116) is an important homeostatic maintenance molecule in the body, but little is known about its role in APAP-induced liver injury (AILI). METHODS: GPR116 expression was determined in both human and mouse AILI models. Hepatic function and damage response were analyzed in hepatocyte-specific GPR116 deletion (GPR116△HC) mice undergoing APAP challenge. RNA-sequencing, immunofluorescence confocal, and co-immunoprecipitation (CO-IP) were employed to elucidate the impact and underlying mechanisms of GPR116 in AILI. RESULTS: Intrahepatic GPR116 was upregulated in human and mice with AILI. GPR116△HC mice were vulnerable to AILI compared to wild-type mice. Overexpression of GPR116 effectively mitigated AILI in wild-type mice and counteracted the heightened susceptibility of GPR116△HC mice to APAP. Mechanistically, GPR116 inhibits the binding immunoglobulin protein (BiP), a critical regulator of ER function, through its interaction with ß-arrestin1, thereby mitigating ER stress during the early stage of AILI. Additionally, the activation of GPR116 by ligand FNDC4 has been shown to confer a protective effect against early hepatotoxicity caused by APAP in murine model. CONCLUSIONS: Upregulation of GPR116 on hepatocytes inhibits ER stress by binding to ß-arrestin1, protecting mice from APAP-induced hepatotoxicity. GPR116 may serve as a promising therapeutic target for AILI.

The SIRT2-AMPK axis regulates autophagy induced by acute liver failure.

This study explores the role of SIRT2 in regulating autophagy and its interaction with AMPK in the context of acute liver failure (ALF). This study investigated the effects of SIRT2 and AMPK on autophagy in ALF mice and TAA-induced AML12 cells. The results revealed that the liver tissue in ALF model group had a lot of inflammatory cell infiltration and hepatocytes necrosis, which were reduced by SIRT2 inhibitor AGK2. In comparison to normal group, the level of SIRT2, P62, MDA, TOS in TAA group were significantly increased, which were decreased in AGK2 treatment. Compared with normal group, the expression of P-PRKAA1, Becilin1 and LC3B-II was decreased in TAA group. However, AGK2 enhanced the expression of P-PRKAA1, Becilin1 and LC3B-II in model group. Overexpression of SIRT2 in AML12 cell resulted in decreased P-PRKAA1, Becilin1 and LC3B-II level, enhanced the level of SIRT2, P62, MDA, TOS. Overexpression of PRKAA1 in AML12 cell resulted in decreased SIRT2, TOS and MDA level and triggered more autophagy. In conclusion, the data suggested the link between AMPK and SIRT2, and reveals the important role of AMPK and SIRT2 in autophagy on acute liver failure.

Insights gained into the injury mechanism of drug and herb induced liver injury in the hepatic microenvironment.

Drug-Induced Liver Injury (DILI) and herb Induced Liver Injury (HILI) continues to pose a substantial challenge in both clinical practice and drug development, representing a grave threat to patient well-being. This comprehensive review introduces a novel perspective on DILI and HILI by thoroughly exploring the intricate microenvironment of the liver. The dynamic interplay among hepatocytes, sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, cholangiocytes, and the intricate vascular network assumes a central role in drug metabolism and detoxification. Significantly, this microenvironment is emerging as a critical determinant of susceptibility to DILI and HILI. The review delves into the multifaceted interactions within the liver microenvironment, providing valuable insights into the complex mechanisms that underlie DILI and HILI. Furthermore, we discuss potential strategies for mitigating drug-induced liver injury by targeting these influential factors, emphasizing their clinical relevance. By highlighting recent advances and future prospects, our aim is to shed light on the promising avenue of leveraging the liver microenvironment for the prevention and mitigation of DILI and HILI. This deeper understanding is crucial for advancing clinical practices and ensuring patient safety in the realm of DILI and HILI.

Hepatoprotective potential of alpha-lipoic acid against gliclazide-induced liver injury in high-glucose-exposed human liver cells and experimental type 2 diabetic rats.

Growing clinical evidence shows that sulfonylurea therapy for patients with type 2 diabetic mellitus (T2DM) contributes to progressive worsening of their liver. The present study presents hepatotoxicity induced by gliclazide, a second-generation sulfonylurea, and alpha-lipoic acid (ALA) as a novel and promising drug for T2DM treatment. Normal human liver cells (HL-7702) were incubated with high-glucose DMEM in the presence or absence of gliclazide and ALA for 72 h, and cell viability and death were measured by flow cytometry. Next, Sprague-Dawley rats were subjected to 12 h of fasting, and fasting blood glucose was measured. The rats were randomized into four groups: HC (healthy control; n = 7), T2DM (diabetic rats without treatment; n = 9), GLC (diabetic rats with 15 mg/kg gliclazide treatment; n = 7) and GLC+ALA (diabetic rats with gliclazide and 60 mg/kg ALA treatment; n = 7). T2DM was induced by a bolus administration of 110 mg/kg nicotinamide and 55 mg/kg streptozotocin intraperitoneally. The experimental protocol lasted for 6 weeks after which the animals were sacrificed and pancreas, liver and blood samples were collected for biochemical, histological and molecular analyses. Compared to healthy control (HC) group, exposure of HL-7702 cells to high glucose induced significant cell death by 19 % (p < 0.001), which was exacerbated with gliclazide treatment by 29 % (p < 0.0001) but markedly reduced by 6 % to near HC value following ALA treatment. In vivo, GLC-treated rats had severe liver damage characterized by increased hepatocellular vacuolation, and significant expression of ED-1, iNOS and caspase-3 as well as markedly high levels of liver enzymes (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase compared to T2DM rats. Interestingly, ALA administration prevented these pathological changes and protected the diabetic liver to levels comparable to HC rats. ALA showed hepatoprotective effect against gliclazide-induced hepatotoxicity by suppressing inflammation and apoptosis while activating antioxidant pathway in the diabetic liver. Abbreviations: ALA, Alpha-lipoic acid; ALT, Alanine aminotransferase; ALP, Alkaline phosphatase; AMPK, Adenosine monophosphate-activated protein kinase; AST, Aspartate aminotransferase; ATP, Adenosine triphosphate; DMEM, Dulbecco's Modified Eagle Medium; EDTA, ethylenediaminetetraacetic acid; FBG, Fasting blood glucose; FBS, Fetal bovine serum; GLC, Gliclazide; GLUT4, Glucose transporter type 4; GSH, Glutathione; H&E, Hematoxylin/Eosin; HbA1c, Glycosylated haemoglobin A1c; HC, Healthy control; HG, Hyperglycemic group; HOMA-ß, Homeostasis model assessment of ß-cell function; IL-1ß, Interleukin-1ß; IL-6, Interleukin-6; iNOS, Inducible nitric oxide synthase; KATP, ATP-dependent potassium channels; MDA, Malondialdehyde; MPTP, Mitochondrial permeability transition pore; NO, Nitric oxide; P/S, Penicillin/streptomycin; PAS, Periodic acid-Schiff; RIA, Radioimmunoassay; ROS, Reactive oxygen species; SOD, Superoxide dismutase; T2DM, Type 2 diabetes mellitus; TBARS, Thiobarbituric acid reactive substances; TNF-α, Tumor necrosis factor-alpha.

In vivo interaction screening reveals liver-derived constraints to metastasis.

It is estimated that only 0.02% of disseminated tumour cells are able to seed overt metastases1. While this suggests the presence of environmental constraints to metastatic seeding, the landscape of host factors controlling this process remains largely unclear. Here, combining transposon technology2 and fluorescence niche labelling3, we developed an in vivo CRISPR activation screen to systematically investigate the interactions between hepatocytes and metastatic cells. We identify plexin B2 as a critical host-derived regulator of liver colonization in colorectal and pancreatic cancer and melanoma syngeneic mouse models. We dissect a mechanism through which plexin B2 interacts with class IV semaphorins on tumour cells, leading to KLF4 upregulation and thereby promoting the acquisition of epithelial traits. Our results highlight the essential role of signals from the liver parenchyma for the seeding of disseminated tumour cells before the establishment of a growth-promoting niche. Our findings further suggest that epithelialization is required for the adaptation of CRC metastases to their new tissue environment. Blocking the plexin-B2-semaphorin axis abolishes metastatic colonization of the liver and therefore represents a therapeutic strategy for the prevention of hepatic metastases. Finally, our screening approach, which evaluates host-derived extrinsic signals rather than tumour-intrinsic factors for their ability to promote metastatic seeding, is broadly applicable and lays a framework for the screening of environmental constraints to metastasis in other organs and cancer types.

Integrator complex subunit 6 promotes hepatocellular steatosis via ß-catenin-PPARγ axis.

Hepatic adipogenesis has common mechanisms with adipocyte differentiation such as PPARγ involvement and the induction of adipose tissue-specific molecules. A previous report demonstrated that integrator complex subunit 6 (INTS6) is required for adipocyte differentiation. This study aimed to investigate INTS6 expression and its role in hepatic steatosis progression. The expression of INTS6 and PPARγ was examined in the liver of a mouse model of steatohepatitis and in paired liver biopsy samples from 11 patients with severe obesity and histologically proven metabolic dysfunction associated steatohepatitis (MASH) before and one year after bariatric surgery. To induce hepatocellular steatosis in vitro, an immortalized human hepatocyte cell line Hc3716 was treated with free fatty acids. In the steatohepatitis mouse model, we observed hepatic induction of INTS6, PPARγ, and adipocyte-specific genes. In contrast, ß-catenin which negatively regulates PPARγ was reduced. Biopsied human livers demonstrated a strong positive correlation (r2 = 0.8755) between INTS6 and PPARγ mRNA levels. After bariatric surgery, gene expressions of PPARγ, FABP4, and CD36 were mostly downregulated. In our in vitro experiments, we observed a concentration-dependent increase in Oil Red O staining in Hc3716 cells after treatment with the free fatty acids. Alongside this change, the expression of INTS6, PPARγ, and adipocyte-specific genes was induced. INTS6 knockdown using siRNA significantly suppressed cellular lipid accumulation together with induction of ß-catenin and PPARγ downregulation. Collectively, INTS6 expression closely correlates with PPARγ. INTS6 suppression significantly reduced hepatocyte steatosis via ß-catenin-PPARγ axis, indicating that INTS6 could be a novel therapeutic target for treating MASH.

Beneficial Effects of Capybara Oil Supplementation on Steatosis and Liver Apoptosis in Obese Mice.

Obesity is a complex chronic disease characterized by excess body fat (adipose) that is harmful to health and has been a major global health problem. It may be associated with several diseases, such as nonalcoholic fatty liver disease (NAFLD). Polyunsaturated fatty acids (PUFA) are lipid mediators that have anti-inflammatory characteristics and can be found in animals and plants, with capybara oil (CO) being a promising source. So, we intend to evaluate the hepatic pathophysiological alterations in C57Bl/6 mice with NAFLD, caused by obesity, and the possible beneficial effects of OC in the treatment of this disease. Eighteen 3-month-old male C57Bl/6 mice received a control or high-fat diet for 18 weeks. From the 15th to the 18th week, the animals received treatment-through orogastric gavage-with placebo or free capybara oil (5 g/kg). Parameters inherent to body mass, glucose tolerance, evaluation of liver enzymes, percentage of hepatic steatosis, oxidative stress, the process of cell death with the apoptotic biomarkers (Bax, Bcl2, and Cytochrome C), and the ultrastructure of hepatocytes were analyzed. Even though the treatment with CO was not able to disassemble the effects on the physiological parameters, it proved to be beneficial in reversing the morphological and ultrastructural damage present in the hepatocytes. Thus, demonstrating that CO has beneficial effects in reducing steatosis and the apoptotic pathway, it is a promising treatment for NAFLD.

Aberrant differentiation and proliferation of hepatocytes in chronic liver injury and liver tumors.

Chronic liver injury induces liver cirrhosis and facilitates hepatocarcinogenesis. However, the effects of this condition on hepatocyte proliferation and differentiation are unclear. We showed that rodent hepatocytes display a ductular phenotype when they are cultured within a collagenous matrix. This process involves transdifferentiation without the emergence of hepatoblastic features and is at least partially reversible. During the ductular reaction in chronic liver diseases with progressive fibrosis, some hepatocytes, especially those adjacent to ectopic ductules, demonstrate ductular transdifferentiation, but the majority of increased ductules originate from the existing bile ductular system that undergoes extensive remodeling. In chronic injury, hepatocyte proliferation is weak but sustained, and most regenerative nodules in liver cirrhosis are composed of clonally proliferating hepatocytes, suggesting that a small fraction of hepatocytes maintain their proliferative capacity in chronic injury. In mouse hepatocarcinogenesis models, hepatocytes activate the expression of various fetal/neonatal genes, indicating that these cells undergo dedifferentiation. Hepatocyte-specific somatic integration of various oncogenes in mice demonstrated that hepatocytes may be the cells of origin for a broad spectrum of liver tumors through transdifferentiation and dedifferentiation. In conclusion, the phenotypic plasticity and heterogeneity of mature hepatocytes are important for understanding the pathogenesis of chronic liver diseases and liver tumors.

Aging promotes metabolic dysfunction-associated steatotic liver disease by inducing ferroptotic stress.

Susceptibility to the biological consequences of aging varies among organs and individuals. We analyzed hepatocyte transcriptomes of healthy young and aged male mice to generate an aging hepatocyte gene signature, used it to deconvolute transcriptomic data from humans and mice with metabolic dysfunction-associated liver disease, validated findings with functional studies in mice and applied the signature to transcriptomic data from other organs to determine whether aging-sensitive degenerative mechanisms are conserved. We discovered that the signature enriches in diseased livers in parallel with degeneration. It is also enriched in failing human hearts, diseased kidneys and pancreatic islets from individuals with diabetes. The signature includes genes that control ferroptosis. Aged mice develop more hepatocyte ferroptosis and liver degeneration than young mice when fed diets that induce metabolic stress. Inhibiting ferroptosis shifts the liver transcriptome of old mice toward that of young mice and reverses aging-exacerbated liver damage, identifying ferroptosis as a tractable, conserved mechanism for aging-related tissue degeneration.