Proteome Characteristics of Non-Alcoholic Steatohepatitis Liver Tissue and Associated Hepatocellular Carcinomas

Chlordecone-induced hepatotoxicity and fibrosis are mediated by the proteasomal degradation of septins

Chlordecone (CLD) is a pesticide persisting in soils and contaminating food webs. CLD is sequestered in the liver and poorly metabolized into chlordecol (CLDOH). In vitro liver cell models were used to investigate the fate and mechanistic effects of CLD and CLDOH using multiomics. A 3D-cell model was used to investigate whether CLD and CLDOH can affect susceptibility to the metabolic dysfunction-associated steatotic liver disease (MASLD). Hepatocytes were more sensitive to CLD than CLDOH. CLDOH was intensively metabolized into a glucuronide conjugate, whereas CLD was sequestered. CLD but not CLDOH induced a depletion of Septin-2,- 7,- 9,- 10,- 11 due to proteasomal degradation. Septin binding with CLD and CLDOH was confirmed by surface plasmon resonance. CLD disrupted lipid droplet size and increased saturated long-chain dicarboxylic acid production by inhibiting stearoyl-CoA desaturase (SCD) abundance. Neither CLD nor CLDOH induced steatosis, but CLD induced fibrosis in the 3D model of MASLD. To conclude, CLD hepatoxicity is specifically driven by the degradation of septins. CLDOH, was too rapidly metabolized to induce septin degradation. We show that the conversion of CLD to CLDOH reduced hepatotoxicity and fibrosis in liver organoids. This suggests that protective strategies could be explored to reduce the hepatotoxicity of CLD.

Identification of key markers for the stages of nonalcoholic fatty liver disease: An integrated bioinformatics analysis and experimental validation

BACKGROUND

The identification of biomarkers for the early diagnosis of nonalcoholic fatty liver disease (NAFLD) is urgently needed. Here, we aimed to identify NAFLD biomarkers in the early stages of steatosis (SS) and nonalcoholic steatohepatitis (NASH) based on differential gene expression from bioinformatics data.

METHODS

A meta-analysis was performed from transcriptomic databases retrieved from public repositories containing data from biopsies of patients at various stages of NAFLD development. The status of the selected molecules was validated in the serum of patients with NAFLD by ELISA.

RESULTS

We identified 121 differentially expressed genes (DEGs) associated with SS and 402 associated with NASH. Gene Ontology (GO) enrichment revealed that the altered genes were primarily associated with dysfunction of primary cellular processes, and pathway analyses were mainly related to cholesterol metabolism. We identified ACSS2, PCSK9, and CYP7A1 as candidate biomarkers for SS and ANGPTL3, CD36, CYP51A1, FASN, FAS, FDFT1, and LSS as candidate biomarkers for NASH.

CONCLUSIONS

By experimental validation of bioinformatics data from patients with NAFLD, we identified promising biomarkers for detecting SS and NASH that might be useful for screening and diagnosing early NAFLD stages in humans.

Mechanism of Action and Related Natural Regulators of Nrf2 in Nonalcoholic Fatty Liver Disease

With the acceleration of people's pace of life, non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in the world, which greatly threatens people's health and safety. Therefore, there is still an urgent need for higher-quality research and treatment in this area. Nuclear factor Red-2-related factor 2 (Nrf2), as a key transcription factor in the regulation of oxidative stress, plays an important role in inducing the body's antioxidant response. Although there are no approved drugs targeting Nrf2 to treat NAFLD so far, it is still of great significance to target Nrf2 to alleviate NAFLD. In recent years, studies have reported that many natural products treat NAFLD by acting on Nrf2 or Nrf2 pathways. This article reviews the role of Nrf2 in the pathogenesis of NAFLD and summarizes the currently reported natural products targeting Nrf2 or Nrf2 pathway for the treatment of NAFLD, which provides new ideas for the development of new NAFLD-related drugs.

Recent Insights into the Biomarkers, Molecular Targets and Mechanisms of Non-Alcoholic Steatohepatitis-Driven Hepatocarcinogenesis

Non-alcoholic fatty liver disease (NAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (NASH) are chronic hepatic conditions leading to hepatocellular carcinoma (HCC) development. According to the recent "multiple-parallel-hits hypothesis", NASH could be caused by abnormal metabolism, accumulation of lipids, mitochondrial dysfunction, and oxidative and endoplasmic reticulum stresses and is found in obese and non-obese patients. Recent translational research studies have discovered new proteins and signaling pathways that are involved not only in the development of NAFLD but also in its progression to NASH, cirrhosis, and HCC. Nevertheless, the mechanisms of HCC developing from precancerous lesions have not yet been fully elucidated. Now, it is of particular importance to start research focusing on the discovery of novel molecular pathways that mediate alterations in glucose and lipid metabolism, which leads to the development of liver steatosis. The role of mTOR signaling in NASH progression to HCC has recently attracted attention. The goals of this review are (1) to highlight recent research on novel genetic and protein contributions to NAFLD/NASH; (2) to investigate how recent scientific findings might outline the process that causes NASH-associated HCC; and (3) to explore the reliable biomarkers/targets of NAFLD/NASH-associated hepatocarcinogenesis.

Considerations for Physiologically Based Modeling in Liver Disease: From Nonalcoholic Fatty Liver (NAFL) to Nonalcoholic Steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD), representing a clinical spectrum ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), is rapidly evolving into a global pandemic. Patients with NAFLD are burdened with high rates of metabolic syndrome-related comorbidities resulting in polypharmacy. Therefore, it is crucial to gain a better understanding of NAFLD-mediated changes in drug disposition and efficacy/toxicity. Despite extensive clinical pharmacokinetic data in cirrhosis, current knowledge concerning pharmacokinetic alterations in NAFLD, particularly at different stages of disease progression, is relatively limited. In vitro-to-in vivo extrapolation coupled with physiologically based pharmacokinetic and pharmacodynamic (IVIVE-PBPK/PD) modeling offers a promising approach for optimizing pharmacologic predictions while refining and reducing clinical studies in this population. Use of IVIVE-PBPK to predict intra-organ drug concentrations at pharmacologically relevant sites of action is particularly advantageous when it can be linked to pharmacodynamic effects. Quantitative systems pharmacology/toxicology (QSP/QST) modeling can be used to translate pharmacokinetic and pharmacodynamic data from PBPK/PD models into clinically relevant predictions of drug response and toxicity. In this review, a detailed summary of NAFLD-mediated alterations in human physiology relevant to drug absorption, distribution, metabolism, and excretion (ADME) is provided. The application of literature-derived physiologic parameters and ADME-associated protein abundance data to inform virtual NAFLD population development and facilitate PBPK/PD, QSP, and QST predictions is discussed along with current limitations of these methodologies and knowledge gaps. The proposed methodologic framework offers great potential for meaningful prediction of pharmacological outcomes in patients with NAFLD and can inform both drug development and clinical practice for this population.

Deep proteomic profiling unveils arylsulfatase A as a non-alcoholic steatohepatitis inducible hepatokine and regulator of glycemic control

Non-alcoholic steatohepatitis (NASH) and type 2 diabetes are closely linked, yet the pathophysiological mechanisms underpinning this bidirectional relationship remain unresolved. Using proteomic approaches, we interrogate hepatocyte protein secretion in two models of murine NASH to understand how liver-derived factors modulate lipid metabolism and insulin sensitivity in peripheral tissues. We reveal striking hepatokine remodelling that is associated with insulin resistance and maladaptive lipid metabolism, and identify arylsulfatase A (ARSA) as a hepatokine that is upregulated in NASH and type 2 diabetes. Mechanistically, hepatic ARSA reduces sulfatide content and increases lysophosphatidylcholine (LPC) accumulation within lipid rafts and suppresses LPC secretion from the liver, thereby lowering circulating LPC and lysophosphatidic acid (LPA) levels. Reduced LPA is linked to improvements in skeletal muscle insulin sensitivity and systemic glycemic control. Hepatic silencing of Arsa or inactivation of ARSA's enzymatic activity reverses these effects. Together, this study provides a unique resource describing global changes in hepatokine secretion in NASH, and identifies ARSA as a regulator of liver to muscle communication and as a potential therapeutic target for type 2 diabetes.

Comparison of hepatic steatosis index as noninvasive diagnostic tool and liver ultrasound for non-alcoholic steatosis in the adult population

Aim

This study aimed to evaluate hepatic steatosis index (HSI) as a non-invasive tool in diagnosing and predicting nonalcoholic fatty liver disease (NAFLD) and to compare it with abdominal ultrasound as the gold standard tool.

Background

NAFLD is a general term attributed to the deposition of adipose tissue in the liver leading to hepatitis, fibrosis, cirrhosis, and also hepatocellular carcinoma (HCC). Rapid and valid screening can remarkably prevent the progression of this disease.

Methods

A total of 464 people were included in the present study based on inclusion criteria. Patients were evaluated for body mass index (BMI), AST, ALT, and ALP indices. The liver echogenicity of patients was evaluated by abdominal ultrasound technique.

Results

The results showed that out of 464 people included in the study, 32.33% represented fatty liver. It was found that 79.1% of patients were female. There was no significant difference between the two groups in terms of age. Furthermore, it was found that ALT, AST, and ALP levels were significantly increased in the two groups of patients compared to the control group. It was determined that out of 150 patients, 75.3% were grade I and 24.7% were grade II NAFLD cases; no grade III cases were observed. The mean HSI for the NAFLD- group was 35.51±5.72 and for the NAFLD+ group was 42.84±5.70, a significant difference. The receiver operating characteristic (ROC) curve also showed that the area under the curve (AUC) of HSI was 0.833 (95% CI, 0.796-0.870) for detecting NAFLD patients. At the cutoff point of > 36.0, the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were 88.7% (95% CI, 82.5-92.5), 63.4% (95% CI, 57.9-68.5), 92.1%, and 53.6%, respectively. Pearson correlation showed a direct and significant correlation between ultrasound data and HSI values.

Conclusion

Overall, the present study results showed that HSI as a non-invasive and non-imaging tool can diagnose NAFLD.

Metabolic and Signaling Roles of Ketone Bodies in Health and Disease

Ketone bodies play significant roles in organismal energy homeostasis, serving as oxidative fuels, modulators of redox potential, lipogenic precursors, and signals, primarily during states of low carbohydrate availability. Efforts to enhance wellness and ameliorate disease via nutritional, chronobiological, and pharmacological interventions have markedly intensified interest in ketone body metabolism. The two ketone body redox partners, acetoacetate and D-β-hydroxybutyrate, serve distinct metabolic and signaling roles in biological systems. We discuss the pleiotropic roles played by both of these ketones in health and disease. While enthusiasm is warranted, prudent procession through therapeutic applications of ketogenic and ketone therapies is also advised, as a range of metabolic and signaling consequences continue to emerge. Organ-specific and cell-type-specific effects of ketone bodies are important to consider as prospective therapeutic and wellness applications increase.

Combined Transcriptomic and Lipidomic Analysis Reveals Dysregulated Genes Expression and Lipid Metabolism Profiles in the Early Stage of Fatty Liver Disease in Rats

Non-alcoholic fatty liver disease develops from simple steatosis to non-alcoholic steatohepatitis (NASH), which then potentially develops into liver cirrhosis. It is a serious threat to human health. Therefore, investigating the formation and development mechanism of non-alcoholic fatty liver disease (NAFLD) is of great significance. Herein, an early model of NAFLD was successfully established by feeding rats with a high-fat and choline-deficient diet. Liver tissue samples were obtained from rats in the fatty liver model group (NAFL) and normal diet control group (CON). Afterward, transcriptome and lipidomic analysis was performed. Transcriptome results revealed that 178 differentially expressed genes were detected in NAFL and CON groups. Out of which, 105 genes were up-regulated, 73 genes were downregulated, and 8 pathways were significantly enriched. A total of 982 metabolites were detected in lipidomic analysis. Out of which 474 metabolites were significantly different, 273 were up-regulated, 201 were downregulated, and 7 pathways were significantly enriched. Based on the joint analysis, 3 common enrichment pathways were found, including cholesterol metabolism and fat digestion and absorption metabolic pathways. Overall, in the early stage of NAFLD, a small number of genetic changes caused a strong response to lipid components. The strongest reflection was glycerides and glycerophospholipids. A significant increase in fatty acid uptake accompanied by cholesterol metabolism is the most prominent metabolic feature of the liver in the early stage of NAFLD. In the early stage of fatty liver, the liver had shown the characteristics of NASH.

LncRNA TP53TG1 Promotes the Growth and Migration of Hepatocellular Carcinoma Cells via Activation of ERK Signaling

Long non-coding RNA (lncRNA) TP53 target 1 (TP53TG1) was discovered as a TP53 target gene. TP53TG1 has been reported as having dual roles by exerting tumor-suppressive and oncogenic activities that vary depending on the cancer type. Yet, the role of TP53TG1 in hepatocellular carcinoma (HCC) is not fully understood. In this study, we performed both gain- and loss-of-function studies to determine the biological role of TP53TG1 in HCC. We found that the knockdown of TP53 in HCC cells caused the upregulation of TP53TG1. Furthermore, we found that the knockdown of TP53TG1 not only suppressed HCC cell proliferation and migration, but also reduced intrinsic ERK signaling. In contrast, the overexpression of TP53TG1 increased ERK activation and enhanced HCC proliferation. In conclusion, our study reveals an oncogenic role of TP53TG1 in HCC, which provides a novel insight into the cell-type-specific function of TP53TG1 in HCC.

Neonatal streptozotocin treatment rapidly causes different subtype of hepatocellular carcinoma without persistent hyperglycemia in 4CS mice fed on a normal diet

Although diabetes mellitus (DM) is a well-known risk factor for hepatocellular carcinoma (HCC), the underlying mechanisms have not yet to be defined. We previously reported that DIAR mice fed with standard murine diet developed type 1 diabetes and HCC at age of 16 weeks old with a neonatal streptozotocin treatment (n-STZ). Because DIAR mice did not manifest obesity nor develop steatohepatitis, hyperglycemia with streptozotocin trigger or streptozotocin alone might turn on the hepato-carcinogenesis. An insulin-recruitment to DIAR-nSTZ mice showed an increased frequency of HCC during the first 12 weeks of age, although the diabetic indications notably improved. To elucidate the role of hyperglycemia in hepato-carcinogenesis, we performed a head-to-head comparative study by using 4CS mice and DIAR mice with n-STZ treatment. Newborn 4CS mice and DIAR mice were divided into STZ treated group and control group. The blood glucose levels of DIAR-nSTZ mice increased at age of eight weeks, while that of 4CS-nSTZ mice were maintained in the normal range. At eight weeks old, three out of five DIAR-nSTZ mice (60%) and one out of ten 4CS-nSTZ mice (10%) developed multiple liver tumors. At age of 12 weeks old, all eight of DIAR-nSTZ mice (100%) and two of 10 4CS-nSTZ mice (20%) developed multiple liver tumors. At 16 weeks old, all animals of DIAR-nSTZ and 4CS-nSTZ mice occurred liver tumors. DIAR-nSTZ showed hyperglycemia and HCC, and 4CS-nSTZ developed HCC without hyperglycemia. These results were interpreted that the onset of HCC maybe not related to the presence or absence of hyperglycemia but nSTZ treatment. On the other hand, since the carcinogenesis of 4CS-nSTZ is delayed compared to DIAR-nSTZ, hyperglycemia may play a role in the progression of carcinogenesis. Histologically, the liver tumor appeared irregularly trabecular arrangements of hepatocytes with various degrees of nuclear atypia. By immunohistochemical analyses, all liver tumors showed positive staining of glutamine synthetase (GS), an established human HCC marker. The expression pattern of GS was divided into a strong diffuse pattern and weak patchy pattern, respectively. The liver tumor showing the weak GS-patchy pattern expressed biliary/stem markers, EpCAM, and SALL4, partially. Because 4CS-nSTZ mice did not show any metabolic complications such as gaining body weight or high blood glucose level, it is a unique animal model with a simple condition to investigate hepatic carcinogenesis by excluding other factors.

Modeling alcohol-associated liver disease in a human Liver-Chip

Alcohol-associated liver disease (ALD) is a global health issue and leads to progressive liver injury, comorbidities, and increased mortality. Human-relevant preclinical models of ALD are urgently needed. Here, we leverage a triculture human Liver-Chip with biomimetic hepatic sinusoids and bile canaliculi to model ALD employing human-relevant blood alcohol concentrations (BACs) and multimodal profiling of clinically relevant endpoints. Our Liver-Chip recapitulates established ALD markers in response to 48 h of exposure to ethanol, including lipid accumulation and oxidative stress, in a concentration-dependent manner and supports the study of secondary insults, such as high blood endotoxin levels. We show that remodeling of the bile canalicular network can provide an in vitro quantitative readout of alcoholic liver toxicity. In summary, we report the development of a human ALD Liver-Chip as a powerful platform for modeling alcohol-induced liver injury with the potential for direct translation to clinical research and evaluation of patient-specific responses.

Cache Domain Containing 1 Is a Novel Marker of Non-Alcoholic Steatohepatitis-Associated Hepatocarcinogenesis

Simple Summary

The aim of the present study was to discover novel early molecular biomarkers of liver neoplasms which arise in non-alcoholic steatohepatitis (NASH) Stelic Animal Model (STAM) mice. Significant increase of lipid deposits, hepatocyte ballooning, fibrosis, and incidences and multiplicities of hepatocellular adenomas and carcinomas were detected in the livers of 18-week-old STAM mice. From the results of proteome analysis of STAM mice hepatocellular carcinomas, significant elevation of a novel protein, cache domain-containing 1 (CACHD1) was found. Furthermore, we observed CACHD1-positive foci in STAM mice livers, which number, area, and cell proliferation index within the foci were significantly elevated. Results of immunohistochemical and in vitro functional analysis indicated that CACHD1 may become a useful early biomarker and potential molecular target in NASH-associated hepatocarcinogenesis, which is involved in control of cell proliferation, autophagy and apoptosis.

Abstract

In the present study, potential molecular biomarkers of NASH hepatocarcinogenesis were investigated using the STAM mice NASH model, characterized by impaired insulin secretion and development of insulin resistance. In this model, 2-days-old C57BL/6N mice were subjected to a single subcutaneous (s.c.) injection of 200 μg streptozotocin (STZ) to induce diabetes mellitus (DM). Four weeks later, mice were administered high-fat diet (HFD) HFD-60 for 14 weeks (STAM group), or fed control diet (STZ group). Eighteen-week-old mice were euthanized to allow macroscopic, microscopic, histopathological, immunohistochemical and proteome analyses. The administration of HFD to STZ-treated mice induced significant fat accumulation and fibrosis development in the liver, which progressed to NASH, and rise of hepatocellular adenomas (HCAs) and carcinomas (HCCs). In 18-week-old animals, a significant increase in the incidence and multiplicity of HCAs and HCCs was found. On the basis of results of proteome analysis of STAM mice HCCs, a novel highly elevated protein in HCCs, cache domain-containing 1 (CACHD1), was chosen as a potential NASH-HCC biomarker candidate. Immunohistochemical assessment demonstrated that STAM mice liver basophilic, eosinophilic and mixed-type altered foci, HCAs and HCCs were strongly positive for CACHD1. The number and area of CACHD1-positive foci, and cell proliferation index in the area of foci in mice of the STAM group were significantly increased compared to that of STZ group. In vitro siRNA knockdown of CACHD1 in human Huh7 and HepG2 liver cancer cell lines resulted in significant inhibition of cell survival and proliferation. Analysis of the proteome of knockdown cells indicated that apoptosis and autophagy processes could be activated. From these results, CACHD1 is an early NASH-associated biomarker of liver preneoplastic and neoplastic lesions, and a potential target protein in DM/NASH-associated hepatocarcinogenesis.

Accumulation of 8-hydroxydeoxyguanosine, L-arginine and Glucose Metabolites by Liver Tumor Cells Are the Important Characteristic Features of Metabolic Syndrome and Non-Alcoholic Steatohepatitis-Associated Hepatocarcinogenesis

To uncover mechanisms and explore novel biomarkers of obesity, type 2 diabetes (T2DM) and nonalcoholic steatohepatitis (NASH)-associated hepatocarcinogenesis, cellular and molecular alterations in the liver, and hepatocellular carcinomas (HCCs) were investigated in NASH model 60-week-old Tsumura, Suzuki, Obese Diabetic (TSOD) mice and NASH HCC patients. Markedly elevated lipid deposition, inflammation, fibrosis, and peroxisome proliferation in the liver, preneoplastic lesions, and HCCs of TSOD mice were accompanied by accumulation of polysaccharides in the cellular cytoplasm and nuclei and increase of oxidative DNA damage marker, 8-hydroxydeoxyguanosine (8-OHdG) formation in the liver and altered foci. Metabolomics of TSOD mice HCCs demonstrated significant elevation of the concentration of amino acid L-arginine, phosphocreatine, S-adenosylmethionine/S-adenosylhomocysteine ratio, adenylate, and guanylate energy charges in coordination with tremendous rise of glucose metabolites, mostly fructose 1,6-diphosphate. L-arginine accumulation in HCCs was associated with significant under-expression of arginase 1 (ARG1), suppression of the urea cycle, methionine and putrescine degradation pathways, activation of Ser and Thr kinase Akt AKT, phosphoinositide 3-kinase (PI3K), extracellular signal-regulated kinase 1/2 (ERK1/2) kinases, β-catenin, mammalian target of rapamycin (mTOR), and cell proliferation. Furthermore, clinicopathological analysis in 20 metabolic syndrome/NASH and 80 HCV-positive HCC patients demonstrated significant correlation of negative ARG1 expression with poor tumor differentiation, higher pathological stage, and significant decrease of survival in metabolic syndrome/NASH-associated HCC patients, thus indicating that ARG1 could become a potential marker for NASH HCC. From these results, formation of oxidative stress and 8-OHdG in the DNA and elevation of glucose metabolites and L-arginine due to ARG1 suppression in mice liver cells are the important characteristics of T2DM/NASH-associated hepatocarcinogenesis, which may take part in activating oxidative stress resistance, synthesis of phosphocreatine, cell signaling, methylation, and proliferation.

Transcriptional Regulation in Non-Alcoholic Fatty Liver Disease

Obesity is the primary risk factor for the pathogenesis of non-alcoholic fatty liver disease (NAFLD), the worldwide prevalence of which continues to increase dramatically. The liver plays a pivotal role in the maintenance of whole-body lipid and glucose homeostasis. This is mainly mediated by the transcriptional activation of hepatic pathways that promote glucose and lipid production or utilization in response to the nutritional state of the body. However, in the setting of chronic excessive nutrition, the dysregulation of hepatic transcriptional machinery promotes lipid accumulation, inflammation, metabolic stress, and fibrosis, which culminate in NAFLD. In this review, we provide our current understanding of the transcription factors that have been linked to the pathogenesis and progression of NAFLD. Using publicly available transcriptomic data, we outline the altered activity of transcription factors among humans with NAFLD. By expanding this analysis to common experimental mouse models of NAFLD, we outline the relevance of mouse models to the human pathophysiology at the transcriptional level.

Characteristics of Immune Response to Tumor-Associated Antigens and Immune Cell Profile in Patients With Hepatocellular Carcinoma

Host antitumor immune responses may be different between hepatocellular carcinoma (HCC) caused by metabolic disorders and HCC associated with hepatitis virus infection. In this study, we examined the immune response of tumor-associated antigen (TAA)-specific T cells and immune cell profile in patients with HCC separated by cause. Thirty-two patients with hepatitis B virus (HBV)-related HCC, 42 patients with hepatitis C virus-related HCC, and 18 patients with nonalcoholic steatohepatitis (NASH)-related HCC were analyzed. The frequencies of TAA-specific T cells, the expression levels of surface markers on each immune cell, and the expression of each TAA in HCC tissue were measured. The immune response to TAA and immune cell profile were markedly different among the three groups. The immune response to TAA in the NASH-related HCC group was weaker than the responses in the other two groups. In patients with NASH-related HCC, the frequencies of effector regulatory T cells (eTregs) and cluster of differentiation 8-positive (CD8⁺ ) T cells strongly expressing cytotoxic T-lymphocyte antigen (CTLA)-4 were high. The frequency of CD8⁺ T cells strongly expressing programmed cell death 1 was the highest in patients with HBV-related HCC. Among these immune cell profiles, the frequencies of C-X-C motif chemokine receptor 3⁺ eTregs and CTLA-4⁺ CD8⁺ T cells were inversely correlated with the strength of the TAA-specific T-cell immune response, and the restoration of TAA-specific T-cell responses by anti-CTLA-4 antibody was observed. Conclusion: The immune response to TAA were markedly different among the three groups, and a correlation with the immune cell profile was observed, suggesting that development of immunotherapy based on the etiology of HCC may lead to more effective treatment outcomes.

EFFECT OF DORSOMEDIAL HYPOTHALAMUS NEUROPEPTIDE Y KNOCKDOWN ON HEPATIC INSULIN SENSITIVITY

Objective

In this study we investigated the effect of dorsomedial hypothalamus (DMH) neuropeptide Y (NPY) knock-down on hepatic insulin sensitivity in high-fat (HF) diet-fed rats.

Methods

Forty-eight Sprague-Dawley rats were randomly assigned to receive bilateral DMH injections of adeno-associated virus AAVshNPY or AAVshCTL and then accessed to regular chow. Five weeks after viral injection, half rats in each group were given access to the HF diet. At 16 weeks, rat livers were collected. Insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K) mRNA expression was measured by qRT-PCR. Blood glucose levels were measured by the oxidase method, serum insulin, triglyceride, and TC levels were measured by Elisa. Pathological changes in the liver were assessed by hematoxylin-eosin (HE) staining. AKT, p-AKT, and GSK-3 levels were measured by western blotting.

Results

Compared with AAVshCTL-injected rats, AAVshNPY-injected rats showed a significant decrease in blood glucose concentrations; serum insulin, triglyceride, and TC; HOMA-IR; and IRS-1 and PI3K mRNA levels (P<0.05). ISI, GSK-3, and p-AKT levels were significantly increased (P<0.05). HE staining showed that AAVshNPY-injected rats fed the HF diet had mild fatty degeneration.

Conclusion

These results suggest that DMH NPY knock-down improves hepatic insulin sensitivity in HF diet-fed rats by activating the hepatic PI3K/AKT insulin signalling pathway.

mTOR Activation in Liver Tumors Is Associated with Metabolic Syndrome and Non-Alcoholic Steatohepatitis in Both Mouse Models and Humans

Non-alcoholic steatohepatitis (NASH) can cause liver fibrosis and cirrhosis, with final progression to hepatocellular carcinoma (HCC) in some cases. Various factors have been suggested to be involved in the development of NASH. Considering the many possible contributing factors, we postulated that mechanisms of progression from NASH to HCC could differ depending on the risk factors. In the present study, we applied two mouse models of NASH⁻HCC and performed histopathological and proteome analyses of mouse liver tumors. Furthermore, to compare the mechanisms of NASH⁻HCC progression in mice and humans, we investigated HCCs in humans with a background of metabolic syndrome and NASH, as well as HCCs associated with hepatitis virus infection by immunohistochemistry. It was demonstrated that upstream regulators associated with the mammalian target of rapamycin (mTOR) pathway were altered in liver tumors of mice with metabolic syndrome characteristics (TSOD mice) using proteome analysis. Immunohistochemical analysis showed that mTOR was characteristically phosphorylated in liver tumors of TSOD mice and HCCs from metabolic syndrome cases in humans. These results indicated that the mTOR pathway is characteristically activated in liver tumors with metabolic syndrome and NASH, unlike liver tumors with other etiologies.

Epigenetically mediated inhibition of S-adenosylhomocysteine hydrolase and the associated dysregulation of 1-carbon metabolism in nonalcoholic steatohepatitis and hepatocellular carcinoma

The substantial rise in the prevalence of nonalcoholic steatohepatitis (NASH), an advanced form of nonalcoholic fatty liver disease, and the strong association between NASH and the development of hepatocellular carcinoma indicate the urgent need for a better understanding of the underlying mechanisms. In the present study, by using the Stelic animal model of NASH and NASH-derived liver carcinogenesis, we investigated the role of the folate-dependent 1-carbon metabolism in the pathogenesis of NASH. We demonstrated that advanced NASH and NASH-related liver carcinogenesis are characterized by a significant dysregulation of 1-carbon homeostasis, with diminished expression of key 1-carbon metabolism genes, especially a marked inhibition of the S-adenosylhomocysteine hydrolase ( Ahcy) gene and an increased level of S-adenosyl-l-homocysteine (SAH). The reduction in Ahcy expression was associated with gene-specific cytosine DNA hypermethylation and enrichment of the gene promoter by trimethylated histone H3 lysine 27 and deacetylated histone H4 lysine 16, 2 main transcription-inhibiting markers. These results indicate that epigenetically mediated inhibition of Ahcy expression may be a driving force in causing SAH elevation and subsequent downstream disturbances in transsulfuration and transmethylation pathways during the development and progression of NASH.-Pogribny, I. P., Dreval, K., Kindrat, I., Melnyk, S., Jimenez, L., de Conti, A., Tryndyak, V., Pogribna, M., Ortega, J. F., James, S. J., Rusyn, I., Beland, F. A. Epigenetically mediated inhibition of S-adenosylhomocysteine hydrolase and the associated dysregulation of 1-carbon metabolism in nonalcoholic steatohepatitis and hepatocellular carcinoma.

Deletion of both p62 and Nrf2 spontaneously results in the development of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is one of the leading causes of chronic liver disease worldwide. However, details of pathogenetic mechanisms remain unknown. Deletion of both p62/Sqstm1 and Nrf2 genes spontaneously led to the development of NASH in mice fed a normal chow and was associated with liver tumorigenesis. The pathogenetic mechanism (s) underlying the NASH development was investigated in p62:Nrf2 double-knockout (DKO) mice. DKO mice showed massive hepatomegaly and steatohepatitis with fat accumulation and had hyperphagia-induced obesity coupled with insulin resistance and adipokine imbalance. They also showed dysbiosis associated with an increased proportion of gram-negative bacteria species and an increased lipopolysaccharide (LPS) level in feces. Intestinal permeability was elevated in association with both epithelial damage and decreased expression levels of tight junction protein zona occludens-1, and thereby LPS levels were increased in serum. For Kupffer cells, the foreign body phagocytic capacity was decreased in magnetic resonance imaging, and the proportion of M1 cells was increased in DKO mice. In vitro experiments showed that the inflammatory response was accelerated in the p62:Nrf2 double-deficient Kupffer cells when challenged with a low dose of LPS. Diet restriction improved the hepatic conditions of NASH in association with improved dysbiosis and decreased LPS levels. The results suggest that in DKO mice, activation of innate immunity by excessive LPS flux from the intestines, occurring both within and outside the liver, is central to the development of hepatic damage in the form of NASH.

Progression of Hepatic Adenoma to Carcinoma in Ogg1 Mutant Mice Induced by Phenobarbital

The carcinogenic potential of phenobarbital (PB) was assessed in a mouse line carrying a mutant Mmh allele of the Mmh/Ogg1 gene encoding the enzyme oxoguanine DNA glycosylase (Ogg1) responsible for the repair of 8-hydroxy-2′-deoxyguanosine (8-OHdG). Mmh homozygous mutant (Ogg1^−/−) and wild-type (Ogg1^+/+) male and female, 10-week-old, mice were treated with 500 ppm PB in diet for 78 weeks. Hepatocellular carcinomas (HCCs) were found in PB-treated Ogg1^−/− mice, while Ogg1^+/+ animals developed only hepatocellular adenomas (HCAs) at the same rate. This was coordinated with PB-induced significant elevation of 8-OHdG formation in DNA and cell proliferation in adjacent liver of Ogg1^−/− mice. Proteome analysis predicted activation of transcriptional factor Nrf2 in the livers and HCAs of PB-administered Ogg1^+/+ mice; however, its activation was insufficient or absent in the livers and HCCs of Ogg1^−/− mice, respectively. Significant elevation of phase I and II metabolizing enzymes was demonstrated in both Ogg1^−/− and Ogg1^+/+ animals. Treatment of Ogg1^−/− mice with PB resulted in significant elevation of cell proliferation in the liver. These results indicate that PB induced progression from HCA to HCC in Ogg1^−/− mice, due to persistent accumulation of DNA oxidative base modifications and suppression of Nrf2-mediated oxidative stress response, resulting in significant elevation of cell proliferation.