Toll-like receptors in liver disease

Fasting in combination with the cocktail Sorafenib:Metformin blunts cellular plasticity and promotes liver cancer cell death via poly-metabolic exhaustion

PURPOSE

Dual-Interventions targeting glucose and oxidative metabolism are receiving increasing attention in cancer therapy. Sorafenib (S) and Metformin (M), two gold-standards in liver cancer, are known for their mitochondrial inhibitory capacity. Fasting, a glucose-limiting strategy, is also emerging as chemotherapy adjuvant. Herein, we explore the anti-carcinogenic response of nutrient restriction in combination with sorafenib:metformin (NR-S:M).

RESULTS

Our data demonstrates that, independently of liver cancer aggressiveness, fasting synergistically boosts the anti-proliferative effects of S:M co-treatment. Metabolic and Cellular plasticity was determined by the examination of mitochondrial and glycolytic activity, cell cycle modulation, activation of cellular apoptosis, and regulation of key signaling and metabolic enzymes. Under NR-S:M conditions, early apoptotic events and the pro-apoptotic Bcl-xS/Bcl-xL ratio were found increased. NR-S:M induced the highest retention in cellular SubG1 phase, consistent with the presence of DNA fragments from cellular apoptosis. Mitochondrial functionality, Mitochondrial ATP-linked respiration, Maximal respiration and Spare respiratory capacity, were all found blunted under NR-S:M conditions. Basal Glycolysis, Glycolytic reserve, and glycolytic capacity, together with the expression of glycogenic (PKM), gluconeogenic (PCK1 and G6PC3), and glycogenolytic enzymes (PYGL, PGM1, and G6PC3), were also negatively impacted by NR-S:M. Lastly, a TMT-proteomic approach corroborated the synchronization of liver cancer metabolic reprogramming with the activation of molecular pathways to drive a quiescent-like status of energetic-collapse and cellular death.

CONCLUSION

Altogether, we show that the energy-based polytherapy NR-S:M blunts cellular, metabolic and molecular plasticity of liver cancer. Notwithstanding the in vitro design of this study, it holds a promising therapeutic tool worthy of exploration for this tumor pathology.

MiRNAs in Alcohol-Related Liver Diseases and Hepatocellular Carcinoma: A Step toward New Therapeutic Approaches?

Alcohol-related Liver Disease (ALD) is the primary cause of chronic liver disorders and hepatocellular carcinoma (HCC) development in developed countries and thus represents a major public health concern. Unfortunately, few therapeutic options are available for ALD and HCC, except liver transplantation or tumor resection for HCC. Deciphering the molecular mechanisms underlying the development of these diseases is therefore of major importance to identify early biomarkers and to design efficient therapeutic options. Increasing evidence indicate that epigenetic alterations play a central role in the development of ALD and HCC. Among them, microRNA importantly contribute to the development of this disease by controlling the expression of several genes involved in hepatic metabolism, inflammation, fibrosis, and carcinogenesis at the post-transcriptional level. In this review, we discuss the current knowledge about miRNAs' functions in the different stages of ALD and their role in the progression toward carcinogenesis. We highlight that each stage of ALD is associated with deregulated miRNAs involved in hepatic carcinogenesis, and thus represent HCC-priming miRNAs. By using in silico approaches, we have uncovered new miRNAs potentially involved in HCC. Finally, we discuss the therapeutic potential of targeting miRNAs for the treatment of these diseases.

The progression of hepatorenal syndrome-acute kidney injury in acute alcohol-associated hepatitis: renal outcomes after liver transplant

Background

Hepatorenal syndrome-acute kidney injury (HRS-AKI) is a complication of advanced liver disease in patients with ascites and circulatory dysfunction. Little data remain on the relationship between HRS-AKI outcomes and different etiologies of liver disease post-liver transplant (LT).

Objectives

The primary aim was to evaluate the effect of HRS-AKI on renal outcomes in patients with acute alcohol-associated hepatitis (AAH) compared to chronic liver disease (CLD) after LT. The secondary aim was to evaluate the impact of acuity and chronicity of alcohol-associated liver disease in patients with HRS-AKI post-LT renal outcomes.

Design

A retrospective observational study of patients undergoing urgent inpatient liver transplant evaluation (LTE) for cirrhosis and AAH at single academic LT center between October 2017 and July 2021 was conducted.

Methods

Patients with HRS-AKI were selected based on indication for LTE: acute AAHHRS or CLDHRS. CLDHRS was categorized by disease etiology: cirrhosis due to alcohol (A-CLDHRS) versus cirrhosis from other causes (O-CLDHRS). CLD patients without HRS-AKI were labeled CLDno HRS.

Results

A total of 210 subjects underwent LTE; 25% were evaluated for AAH and 75% were evaluated for CLD. Hepatorenal syndrome was more common in subjects evaluated for AAH (37/47) than CLD (104/163) (78.7 versus 63.8%, p = 0.04). For the primary outcome, AAHHRS subjects required ⩾30 days post-LT renal replacement therapy (RRT) more often than subjects with CLDHRS (p = 0.02) and CLDno HRS (p < 0.01). There was no significant difference in other forms of long-term renal outcomes including kidney transplant referral and kidney transplant among cohorts. In subgroup analysis, 30-days post-LT RRT was more common in AAHHRS than in A-CLDHRS (p = 0.08). Logistic regression showed that AAHHRS conferred a 20× and 3.3× odds of requiring ⩾30 days post-LT RRT compared to CLDno HRS and CLDHRS, respectively. Postoperative complications were similar across cohorts, but had a significant effect on 30-day renal outcome post-LT.

Conclusions

Patients with AAH were more likely to develop HRS and require RRT pre- and post-LT at our center. The etiology of hepatic decompensation and postoperative complications affect renal recovery post-LT. The systemic inflammation of AAH in addition to conditions favoring renal hypoperfusion may contribute to the unfavorable outcomes of HRS-AKI after LT in this patient population.

Neferine ameliorates nonalcoholic steatohepatitis through regulating AMPK pathway

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), peculiarly nonalcoholic steatohepatitis (NASH), has become the main cause of liver transplantation and liver-related death. However, the US Food and Drug Administration has not approved a specific medication for treating NASH. Neferine (NEF), a natural bisbenzylisoquinoline alkaloid separated from the traditional Chinese medicine Nelumbinis plumula, has a variety of pharmacological properties, especially on metabolic diseases. Nevertheless, the anti-NASH effect and mechanisms of NEF remain unclear.

PURPOSE

This study aimed to investigate the amelioration of NEF on NASH and the potential mechanisms.

STUDY DESIGN

HepG2 cells, hepatic stellate cells (HSCs) and high-fat diet (HFD)+carbon tetrachloride (CCl₄) induced C57BL/6 mice were used to observe the effect of NEF against NASH and investigate the engaged mechanism.

METHODS

HSCs and HepG2 cells stimulated by oleic acid (OA) were treated with NEF. C57BL/6 mice were fed with HFD+CCl₄ to induce NASH mouse model and treated with or without NEF (5 mg/kg or 10 mg/kg, once daily, i.p) for 4 weeks.

RESULTS

NEF significantly attenuated the accumulation of lipid droplets, intracellular triglyceride (TG) levels and hepatocytes apoptosis in OA-exposed HepG2 cells. NEF not only enhanced the AMPK and ACC phosphorylation in OA-stimulated HepG2 cells, but also reduced inflammatory response and fibrosis in lipopolysaccharide (LPS)-stimulated HepG2 and in LX-2, respectively. In HFD+CCl₄-induced NASH mice, pathological staining confirmed NEF treatment mitigated hepatic lipid deposition, inflammatory cell infiltration as well as hepatic fibrosis. Furthermore, the liver weight, serum and hepatic TG and total cholesterol (TC) and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were decreased compared with the model group. HFD+CCl₄ also induced the upregulation of specific proteins and genes associated to inflammation (ILs, TNF-α, NLRP3, ASC, CCL2 and CXCL10) and hepatic fibrosis (collagens, α-SMA, TGF-β and TIPM1), which were also suppressed by NEF treatment.

CONCLUSION

Our results demonstrated that NEF played a protective role in hepatic steatosis via the regulation of AMPK pathways, which may serve as an attractive candidate for a potential novel strategy on prevention and treatment of NASH.

Innate Immune System in the Pathogenesis of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a prevalent condition characterized by lipid accumulation in hepatocytes with low alcohol consumption. The development of sterile inflammation, which occurs in response to a range of cellular stressors or injuries, has been identified as a major contributor to the pathogenesis of NAFLD. Recent studies of the pathogenesis of NAFLD reported the newly developed roles of damage-associated molecular patterns (DAMPs). These molecules activate pattern recognition receptors (PRRs), which are placed in the infiltrated neutrophils, dendritic cells, monocytes, or Kupffer cells. DAMPs cause the activation of PRRs, which triggers a number of immunological responses, including the generation of cytokines that promote inflammation and the localization of immune cells to the site of the damage. This review provides a comprehensive overview of the impact of DAMPs and PRRs on the development of NAFLD.

Immune cells and their derived microRNA-enriched extracellular vesicles in nonalcoholic fatty liver diseases: Novel therapeutic targets

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. Despite extensive research and multiple clinical trials, there are still no FDA-approved therapies to treat the most severe forms of NAFLD. This is largely due to its complicated etiology and pathogenesis, which involves visceral obesity, insulin resistance, gut dysbiosis, etc. Although inflammation is generally believed to be one of the critical factors that drive the progression of simple steatosis to nonalcoholic steatohepatitis (NASH), the exact type of inflammation and how it contributes to NASH pathogenesis remain largely unknown. Liver inflammation is accompanied by the elevation of inflammatory mediators, including cytokines and chemokines and consequently intrahepatic infiltration of multiple types of immune cells. Recent studies revealed that extracellular vesicles (EVs) derived from inflammatory cells and hepatocytes play an important role in controlling liver inflammation during NASH. In this review, we highlight the roles of innate and adaptive immune cells and their microRNA-enriched EVs during NAFLD development and discuss potential drugs that target inflammatory pathways for the treatment of NAFLD.

Immune and metabolic cross-links in the pathogenesis of comorbid non-alcoholic fatty liver disease

In recent years, there has been a steady growth of interest in non-alcoholic fatty liver disease (NAFLD), which is associated with negative epidemiological data on the prevalence of the disease and its clinical significance. NAFLD is closely related to the metabolic syndrome and these relationships are the subject of active research. A growing body of evidence shows cross-linkages between metabolic abnormalities and the innate immune system in the development and progression of NAFLD. These links are bidirectional and largely still unclear, but a better understanding of them will improve the quality of diagnosis and management of patients. In addition, lipid metabolic disorders and the innate immune system link NAFLD with other diseases, such as atherosclerosis, which is of great clinical importance.

Neonatal Orally Administered Zingerone Attenuates Alcohol-Induced Fatty Liver Disease in Experimental Rat Models

Alcohol intake at different developmental stages can lead to the development of alcohol-induced fatty liver disease (AFLD). Zingerone (ZO) possess hepato-protective properties; thus, when administered neonatally, it could render protection against AFLD. This study aimed to evaluate the potential long-term protective effect of ZO against the development of AFLD. One hundred and twenty-three 10-day-old Sprague-Dawley rat pups (60 males; 63 females) were randomly assigned to four groups and orally administered the following treatment regimens daily during the pre-weaning period from postnatal day (PND) 12-21: group 1-nutritive milk (NM), group 2-NM +1 g/kg ethanol (Eth), group 3-NM + 40 mg/kg ZO, group 4-NM + Eth +ZO. From PND 46-100, each group from the neonatal stage was divided into two; subgroup I had tap water and subgroup II had ethanol solution as drinking fluid, respectively, for eight weeks. Mean daily ethanol intake, which ranged from 10 to 14.5 g/kg body mass/day, resulted in significant CYP2E1 elevation (p < 0.05). Both late single hit and double hit with alcohol increased liver fat content, caused hepatic macrosteatosis, dysregulated mRNA expression of SREBP1c and PPAR-α in male and female rats (p < 0.05). However, neonatal orally administered ZO protected against liver lipid accretion and SREBP1c upregulation in male rats only and attenuated the alcohol-induced hepatic PPAR-α downregulation and macrosteatosis in both sexes. This data suggests that neonatal orally administered zingerone can be a potential prophylactic agent against the development of AFLD.

CD4+ T cell activation and inflammation in NASH-related fibrosis

Liver fibrosis is a common pathological feature of end stage liver failure, a severe life-threatening disease worldwide. Nonalcoholic fatty liver disease (NAFLD), especially its more severe form with steatohepatitis (NASH), results from obesity, type 2 diabetes and metabolic syndrome and becomes a leading cause of liver fibrosis. Genetic factor, lipid overload/toxicity, oxidative stress and inflammation have all been implicated in the development and progression of NASH. Both innate immune response and adaptive immunity contribute to NASH-associated inflammation. Innate immunity may cause inflammation and subsequently fibrosis via danger-associated molecular patterns. Increasing evidence indicates that T cell-mediated adaptive immunity also provokes inflammation and fibrosis in NASH via cytotoxicity, cytokines and other proinflammatory and profibrotic mediators. Recently, the single-cell transcriptome profiling has revealed that the populations of CD4+ T cells, CD8+ T cells, γδ T cells, and TEMs are expanded in the liver with NASH. The activation of T cells requires antigen presentation from professional antigen-presenting cells (APCs), including macrophages, dendritic cells, and B-cells. However, since hepatocytes express MHCII molecules and costimulators, they may also act as an atypical APC to promote T cell activation. Additionally, the phenotypic switch of hepatocytes to proinflammatory cells in NASH contributes to the development of inflammation. In this review, we focus on T cells and in particular CD4+ T cells and discuss the role of different subsets of CD4+ T cells including Th1, Th2, Th17, Th22, and Treg in NASH-related liver inflammation and fibrosis.

Tremella fuciformis Crude Polysaccharides Attenuates Steatosis and Suppresses Inflammation in Diet-Induced NAFLD Mice

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disorder characterized by an enhanced accumulation of lipids, which affects around 40% of the world's population. The T. fuciformis fungus possesses immunomodulatory activity and other beneficial properties that may alleviate steatosis through a different mechanism. The present study was designed to evaluate the effect T. fuciformis crude polysaccharides (TFCP) on inflammatory and lipid metabolism gene expression, oxidative stress, and lipid profile. Mice were divided into groups receiving (a) a normal chow diet (NCD), (b) a methionine-choline-deficient (MCD) diet, and (c) a MCD diet with TFCP. Liver histopathology was performed, and the hepatic gene expression levels were estimated using qRT-PCR. The lipid profiles, ALT, AST, and efficient oxidative enzymes were analyzed using ELISA. The TFCP administration in the MCD-fed mice suppressed hepatic lipid accumulation, lipid metabolism-associated genes (HMGCR, FABP, SREBP, ACC, and FAS), and inflammation-associated genes (IL-1β, TLR4, TNF-α, and IL-6) whilst enhancing the expression of HNF4α genes. TFCP mitigated against oxidative stress and normalized healthy lipid profiles. These results highlighted that TFCP prevents NAFLD through the inhibition of oxidative stress and inflammation, suggesting TFCP would potentially be an effective therapeutic agent against NAFLD progression.

Circulating microbiome in patients with portal hypertension

Portal hypertension (PH) in liver cirrhosis leads to increased gut permeability and the translocation of bacteria across the gut-liver axis. Microbial DNA has recently been detected in different blood compartments; however, this phenomenon has not been thoroughly analyzed in PH. This study aimed to explore circulating bacterial DNA signatures, inflammatory cytokines, and gut permeability markers in different blood compartments (peripheral and hepatic veins) of patients with cirrhosis and PH. The 16S rRNA blood microbiome profiles were determined in 58 patients with liver cirrhosis and 46 control patients. Taxonomic differences were analyzed in relation to PH, liver function, inflammatory cytokines, and gut permeability markers. Circulating plasma microbiome profiles in patients with cirrhosis were distinct from those of the controls and were characterized by enrichment of Comamonas, Cnuella, Dialister, Escherichia/Shigella, and Prevotella and the depletion of Bradyrhizobium, Curvibacter, Diaphorobacter, Pseudarcicella, and Pseudomonas. Comparison of peripheral and hepatic vein blood compartments of patients with cirrhosis did not reveal differentially abundant taxa. Enrichment of the genera Bacteroides, Escherichia/Shigella, and Prevotella was associated with severe PH (SPH) in both blood compartments; however, circulating microbiome profiles could not predict PH severity. Escherichia/Shigella and Prevotella abundance was correlated with IL-8 levels in the hepatic vein. In conclusion, we demonstrated a distinct circulating blood microbiome profile in patients with cirrhosis, showing that specific bacterial genera in blood are marginally associated with SPH, Model for End-Stage Liver Disease score, and inflammation biomarkers; however, circulating microbial composition failed to predict PH severity.

CD73 Attenuates Alcohol-Induced Liver Injury and Inflammation via Blocking TLR4/MyD88/NF-κB Signaling Pathway

Background

Alcoholic liver disease (ALD) is liver damage caused by long-term drinking. Inflammation plays a central role in the progression of ALD. CD73 is a ubiquitously expressed glycosylphosphatidylinositol-anchored glycoprotein that is a key enzyme that converts ATP into adenosine. Evidence has shown that CD73 plays an important role in many diseases, but the role and mechanism of CD73 in alcohol-induced liver injury and inflammation is still unclear.

Methods

The alcohol-induced liver injury and inflammation mouse model was established. The rAAV9-CD73 was used to overexpress CD73. Isolation of primary macrophages (MΦ) from the liver was conducted. The effects of CD73 on alcohol-induced liver injury and inflammation were evaluated by quantitative real‑time PCR, Western blotting, ELISA, and immunohistochemical assay. Flow cytometry was used to detect the cell cycle and apoptosis.

Results

Our results showed that overexpression of CD73 can reduce alcohol-induced liver damage, lipid accumulation, and the secretion of inflammatory cytokines. pEX3-CD73 can promote RAW264.7 cells proliferation and inhibit apoptosis via suppressing the activation of TLR4/MyD88/NF-κB signaling pathway. Inhibition of TLR4 further enhanced the anti-inflammatory effect of overexpression of CD73.

Conclusion

Overexpression of CD73 can reduce alcohol-induced liver injury and inflammation. CD73 may serve as a potential therapeutic target for ALD.

New perspective on fecal microbiota transplantation in liver diseases

Chronic liver disease including non-alcoholic fatty liver disease and alcohol-related liver disease is one of the most common diseases worldwide. The gut-liver axis plays an important role in the pathogenesis of liver disease. Small intestinal bacterial overgrowth, dysbiosis, leaky bowel, bacterial translocation, and imbalanced metabolites are related to the progression of chronic liver disease. Recently, novel therapeutic approaches for microbiota modulation such as personalized diet, probiotics, prebiotics, antibiotics, engineered microbiotas, phage therapy, stomach operation, and fecal microbiota transplantation (FMT) have been proposed with numerous promising results in the effectiveness and clinical application. Although the evidence is still lacking, FMT, a type of fecal bacteriotherapy, has been known as a candidate for the treatment of liver disease. This review article focuses on the most recent advances in our understanding of FMT in chronic liver disease such as non-alcoholic and alcohol-related liver disease.

Review on Biological Characteristics of Kv1.3 and Its Role in Liver Diseases

The liver accounts for the largest proportion of macrophages in all solid organs of the human body. Liver macrophages are mainly composed of cytolytic cells inherent in the liver and mononuclear macrophages recruited from the blood. Monocytes recruitment occurs mainly in the context of liver injury and inflammation and can be recruited into the liver and achieve a KC-like phenotype. During the immune response of the liver, macrophages/KC cells release inflammatory cytokines and infiltrate into the liver, which are considered to be the common mechanism of various liver diseases in the early stage. Meanwhile, macrophages/KC cells form an interaction network with other liver cells, which can affect the occurrence and progression of liver diseases. From the perspective of liver disease treatment, knowing the full spectrum of macrophage activation, the underlying molecular mechanisms, and their implication in either promoting liver disease progression or repairing injured liver tissue is highly relevant from a therapeutic point of view. Kv1.3 is a subtype of the voltage-dependent potassium channel, whose function is closely related to the regulation of immune cell function. At present, there are few studies on the relationship between Kv1.3 and liver diseases, and the application of its blockers as a potential treatment for liver diseases has not been reported. This manuscript reviewed the physiological characteristics of Kv1.3, the relationship between Kv1.3 and cell proliferation and apoptosis, and the role of Kv1.3 in a variety of liver diseases, so as to provide new ideas and strategies for the prevention and treatment of liver diseases. In short, by understanding the role of Kv1.3 in regulating the functions of immune cells such as macrophages, selective blockers of Kv1.3 or compounds with similar functions can be applied to alleviate the progression of liver diseases and provide new ideas for the prevention and treatment of liver diseases.

In Vitro Three-Dimensional Liver Models for Nanomaterial DNA Damage Assessment

Whilst the liver possesses the ability to repair and restore sections of damaged tissue following acute injury, prolonged exposure to engineered nanomaterials (ENM) may induce repetitive injury leading to chronic liver disease. Screening ENM cytotoxicity using 3D liver models has recently been performed, but a significant challenge has been the application of such in vitro models for evaluating ENM associated genotoxicity; a vital component of regulatory human health risk assessment. This review considers the benefits, limitations, and adaptations of specific in vitro approaches to assess DNA damage in the liver, whilst identifying critical advancements required to support a multitude of biochemical endpoints, focusing on nano(geno)toxicology (e.g., secondary genotoxicity, DNA damage, and repair following prolonged or repeated exposures).

IFN-γ contributes to the hepatic inflammation in HFD-induced nonalcoholic steatohepatitis by STAT1β/TLR2 signaling pathway

Growing research evidence suggests that elevated TLR2 is closely related to the occurrence and development of nonalcoholic steatohepatitis (NASH). However, a little is known about its regulatory mechanism. Here, we found that IFN-γ and TLR2 expression is significantly upregulated in NASH associated rat liver specimens. Meanwhile, IFN-γ positively regulated the expression of TLR2 and its target genes in NR8383 rat macrophage cells in dose- & time-dependent manner. Importantly, IFN-γ also regulated the related transcriptional factors pSTAT1 and IRF1. Moreover, we identified that the DNA fragment from -1000 to -200 bp of the TLR2 promoter region is responsible for STAT1 binding, especially the STAT1-BS3 (-591∼-573 bp). Further investigation verified that STAT1β is essential in this process, rather than STAT1α. Overall, our findings suggest that IFN-γ promotes TLR2 transcription and its target genes expression by STAT1β. This leads to the hepatic inflammation vicious cycle in NASH and provides new potential targets for treating NASH.

Pathogenesis of NASH and Promising Natural Products

Nonalcoholic steatohepatitis (NASH) is a common clinical condition that can lead to advanced liver diseases. The mechanism of the diaease progression, which is lacking effective therapy, remains obsure. Therefore, there is a need to understand the pathogenic mechanisms responsible for disease development and progression in order to develop innovative therapies. To accomplish this goal, experimental animal models that recapitulate the human disease are necessary. Currently, an increasing number of studies have focused on natural constituents from medicinal plants which have been emerged as a new hope for NASH. This review summarized the pathogenesis of NASH, animal models commonly used, and the promising targets for therapeutics. We also reviewed the natural constituents as potential NASH therapeutic agents.

Inhibition of IRAK4 kinase activity improves ethanol-induced liver injury in mice

BACKGROUNDS & AIMS

Alcohol-related liver disease (ALD) is a major cause of chronic liver disease worldwide with limited therapeutic options. Interleukin-1 receptor associated kinase 4 (IRAK4), the master kinase of Toll-like receptor (TLR)/IL-1R-mediated signalling activation, is considered a novel therapeutic target in inflammatory diseases, but has not been investigated in the context of ALD.

METHODS

IRAK4 phosphorylation and IRAK1 protein were analysed in liver from alcohol-related hepatitis patients and healthy controls. IRAK4 kinase activity-inactive knock-in (Irak4 KI) mice and bone marrow chimeric mice were exposed to chronic ethanol-induced liver injury. IL-1β-induced IRAK4-mediated signalling and acute phase response were investigated in cultured hepatocytes. IRAK1/4 inhibitor was used to test the therapeutic potential for ethanol-induced liver injury in mice.

RESULTS

Increased IRAK4 phosphorylation and reduced IRAK1 protein were found in livers of patients with alcoholic hepatitis. In the chronic ethanol-induced liver injury mouse model, hepatic inflammation and hepatocellular damage were attenuated in Irak4 KI mice. IRAK4 kinase activity promotes expression of acute phase proteins in response to ethanol exposure, including C-reactive protein and serum amyloid A1 (SAA1). SAA1 and IL-1β synergistically exacerbate ethanol-induced cell death ex vivo. Pharmacological blockage of IRAK4 kinase abrogated ethanol-induced liver injury, inflammation, steatosis, as well as acute phase gene expression and protein production in mice.

CONCLUSIONS

Our data elucidate the critical role of IRAK4 kinase activity in the pathogenesis of ethanol-induced liver injury in mice and provide preclinical validation for use of an IRAK1/4 inhibitor as a new potential therapeutic strategy for the treatment of ALD.

LAY SUMMARY

Herein, we have identified the role of IRAK4 kinase activity in the development of alcohol-induced liver injury in mice. Hepatocyte-specific IRAK4 is associated with an acute phase response and release of proinflammatory cytokines/chemokines, which synergistically exacerbate alcohol-induced hepatocyte cell death ex vivo. Pharmacological inhibition of IRAK4 kinase activity effectively attenuates alcohol-induced liver injury in mice and could have therapeutic implications.

Effective Combination Therapy of Angiotensin-II Receptor Blocker and Rifaximin for Hepatic Fibrosis in Rat Model of Nonalcoholic Steatohepatitis

The progression of nonalcoholic steatohepatitis (NASH) is complicated. The multiple parallel-hits theory is advocated, which includes adipocytokines, insulin resistance, endotoxins, and oxidative stress. Pathways involving the gut–liver axis also mediate the progression of NASH. Angiotensin-II receptor blockers (ARB) suppress hepatic fibrosis via the activation of hepatic stellate cells (HSCs). Rifaximin, a nonabsorbable antibacterial agent, is used for the treatment of hepatic encephalopathy and has been recently reported to improve intestinal permeability. We examined the inhibitory effects on and mechanism of hepatic fibrogenesis by combining ARB and rifaximin administration. Fischer 344 rats were fed a choline-deficient/l-amino acid-defined (CDAA) diet for 8 weeks to generate the NASH model. The therapeutic effect of combining an ARB and rifaximin was evaluated along with hepatic fibrogenesis, the lipopolysaccharide–Toll-like receptor 4 (TLR4) regulatory cascade, and intestinal barrier function. ARBs had a potent inhibitory effect on hepatic fibrogenesis by suppressing HSC activation and hepatic expression of transforming growth factor-β and TLR4. Rifaximin reduced intestinal permeability by rescuing zonula occludens-1 (ZO-1) disruption induced by the CDAA diet and reduced portal endotoxin. Rifaximin directly affect to ZO-1 expression on intestinal epithelial cells. The combination of an ARB and rifaximin showed a stronger inhibitory effect compared to that conferred by a single agent. ARBs improve hepatic fibrosis by inhibiting HSCs, whereas rifaximin improves hepatic fibrosis by improving intestinal permeability through improving intestinal tight junction proteins (ZO-1). Therefore, the combination of ARBs and rifaximin may be a promising therapy for NASH fibrosis.

Fibrinogen-like protein 2 aggravates nonalcoholic steatohepatitis via interaction with TLR4, eliciting inflammation in macrophages and inducing hepatic lipid metabolism disorder

Rationale: The functions of fibrinogen-like protein 2 (fgl2) have been studied in many inflammatory and neoplastic diseases, but the role of fgl2 in nonalcoholic fatty liver disease has not yet been elucidated. In this study, we sought to investigate the role of fgl2 in the pathogenesis of nonalcoholic steatohepatitis (NASH). Methods: Hepatic fgl2 expression was tested in patients with nonalcoholic fatty liver (NAFL) or NASH and controls. Wild-type and fgl2-/- C57BL/6 mice were subjected to a methionine/choline-deficient (MCD) diet or a high-fat diet (HFD) to establish NASH models. Bone marrow-derived macrophages (BMDMs) stimulated with LPS or free fatty acids were used for the in vitro study. Results: In both humans and mice with NASH, macrophage accumulation was concomitant with significantly increased fgl2 expression in the liver. Fgl2 deficiency attenuated liver steatosis and inflammation in diet-induced murine models of NASH. In both liver tissues and BMDMs from NASH mice, fgl2 deficiency resulted in reduced levels of proinflammatory cytokines and reactive oxygen species (ROS) compared with levels in wild-type controls. Activation of NF-κB, p38-MAPK and NLRP3 inflammasomes was also suppressed upon fgl2 disruption. Moreover, lipogenic genes (Fasn and SREBP-2) were downregulated while lipolytic genes (PPAR and CPT1A) were upregulated in the livers of fgl2-/- NASH mice. Primary hepatocytes incubated with the medium collected from fgl2-/- BMDMs showed less fat deposition than those incubated with WT BMDMs. Furthermore, we discovered that fgl2 combined with TLR4 mediates the activation of the Myd88-dependent signaling pathway, which may contribute to inflammation and lipid metabolism disorders. Conclusions: These data suggest that fgl2 aggravates the progression of NASH through activation of NF-κB, p38-MAPK and NLRP3 inflammasomes in macrophages, which consequently induces overproduction of proinflammatory cytokines and lipid metabolism disorders. An interaction of fgl2 and TLR4 may in part contribute to the activation of inflammatory signaling pathways in macrophages.

TLR4 knockout upregulates the expression of Mfn2 and PGC-1α in a high-fat diet and ischemia-reperfusion mice model of liver injury

AIMS

Patients with nonalcoholic fatty liver disease (NAFLD) have less tolerance to ischemia-reperfusion injury (IRI) of the liver than those with the healthy liver; hence have a higher incidence of severe complications after surgery. This study aimed to investigate the dynamics of the liver and mitochondrial damage and the impact of TLR4 knockout (TLR4KO) on Mfn2 expression in the composite model of NAFLD and IRI.

MAIN METHODS

We performed high-fat diet (HFD) feeding and ischemia reperfusion (IR) on wild type (WT) and TLR4 knockout TLR4KO mice.

KEY FINDINGS

The degree of structural and functional injuries to the liver and mitochondria (NAFLD and IRI) is greater than that caused by a single factor (NAFLD or IRI) or a simple superposition of both. The IL-6 and TNF-α expressions were significantly suppressed (P < .05), while PGC-1α and Mfn2 expressions were up-regulated considerably (P < .05) after TLR4KO. Furthermore, mitochondrial fusion increased, while ATP consumption and ROS production decreased significantly after TLR4KO (P < .05). The degree of reduction of compound injury by TLR4KO is more significant than the reduction degree of single factor injury. Also, TNF-α and IL-6 levels can be used predictive markers for mitochondrial damage and liver tolerance to NAFLD and IRI.

SIGNIFICANCE

TLR4KO upregulates the expression of Mfn2 and PGC-1α in the composite model of NAFLD and IRI. This pathway may be related to IL-6 and TNF-α. This evidence provides theoretical and experimental basis for the subsequent Toll-like receptor 4 (TLR4) receptor targeted therapy.

Antifibrotic Effects of a Barbituric Acid Derivative on Liver Fibrosis by Blocking the NF-κB Signaling Pathway in Hepatic Stellate Cells

Hepatic stellate cells (HSCs) are the major profibrogenic cells that promote the pathogenesis of liver fibrosis. The crosstalk between transforming growth factor-β1 (TGF-β1) signaling and lipopolysaccharide (LPS)-induced NF-κB signaling plays a critical role in accelerating liver fibrogenesis. Until now, there have been no FDA-approved drug treatments for liver fibrosis. Barbituric acid derivatives have been used as antiasthmatic drugs in the clinic; however, the effect of barbituric acid derivatives in treating liver fibrosis remains unknown. In this study, we synthesized a series of six barbituric acid (BA) derivatives, and one of the compounds, BA-5, exhibited the best ability to ameliorate TGF-β1-induced HSC activation without overt cytotoxic effects. Then, we treated HSCs and RAW264.7 macrophages with BA-5 to analyze the cross-talk of anti-fibrotic and anti-inflammatory effects. Carbon tetrachloride (CCl₄)-induced liver fibrosis mouse model was used to evaluate the therapeutic effects of BA-5. Treatment with BA-5 inhibited TGF-β1-induced α-SMA, collagen1a2, and phosphorylated smad2/3 expression in HSCs. Furthermore, BA-5 treatment reversed the LPS-induced reduction in BAMBI protein and decreased IκBα and NF-κB phosphorylation in HSCs. NF-κB nuclear translocation, MCP-1 secretion, and ICAM-1 expression were also inhibited in BA-5-treated HSCs. Conditioned medium collected from BA-5-treated HSCs showed a reduced ability to activate RAW264.7 macrophages by inhibiting the MAPK pathway. In the mouse model, BA-5 administration reduced CCl₄-induced liver damage, liver fibrosis, and F4/80 expression without any adverse effects. In conclusion, our study showed that the barbituric acid derivative BA-5 inhibits HSCs activation and liver fibrosis by blocking both the TGF-β1 and LPS-induced NF-κB signaling pathways and further inhibits macrophages recruitment and activation.

Are Probiotics Effective in Targeting Alcoholic Liver Diseases?

Alcoholic liver disease (ALD) encompasses a broad spectrum of disorders including steatosis, steatohepatitis, fibrosis, and cirrhosis. Despite intensive research in the last two decades, there is currently no Food and Drug Administration-approved therapy for treating ALD. Several studies have demonstrated the importance of the gut-liver axis and gut microbiome on the pathogenesis of ALD. Alcohol may induce intestinal dysbiosis and increased intestinal permeability, which in turn result in increased levels of pathogen-associated molecular patterns such as lipopolysaccharide (LPS) and translocation of microbial products from the gut to the liver (bacterial translocation). LPS is an inflammatory signal that activates toll-like receptor 4 on Kupffer cells, contributing to the inflammation observed in ALD. Recently, probiotics have been shown to be effective in reducing or preventing the progression of ALD. A potential mechanism is that the probiotics transforms the composition of intestinal microbiota, which leads to reductions in alcohol-induced dysbiosis, intestinal permeability, bacterial translocation, endotoxemia, and consequently, the development of ALD. While transformation of intestinal microbiota by probiotics appears to be a promising therapeutic strategy for the treatment of intestinal barrier dysfunction, there is a scarcity of research that studies probiotics in the context of ALD. In this review, we discuss the potential therapeutic applications of probiotics in the treatment of ALD.

Recent advances in alcoholic hepatitis

Alcoholic hepatitis is the severest clinical presentation of alcoholic liver disease. Lacking an effective pharmacologic treatment, alcoholic hepatitis is associated with a poor prognosis and its recovery relies mostly on abstinence. With alcohol use disorder being universally on the rise, the impact of alcoholic hepatitis on society and health-care costs is expected to increase significantly. Prognostic factors and liver biopsy can help with timely diagnosis, to determine eligibility and response to corticosteroids, and for prognostication and transplant referral. Although recent discoveries in the pathophysiology of alcoholic hepatitis are encouraging and could pave the way for novel treatment modalities, a multidisciplinary approach considering timely identification and treatment of liver-related complications, infectious and metabolic disease, malnutrition, and addiction counseling should be emphasized. Apart from proper selection of candidates, transplant programs should provide adequate post-transplant addiction support in order to make of early liver transplantation for alcoholic hepatitis the ultimate sobering experience in the next decade.

Nonalcoholic Fatty Liver Disease in Adults: Current Concepts in Etiology, Outcomes, and Management

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of disease, extending from simple steatosis to inflammation and fibrosis with a significant risk for the development of cirrhosis. It is highly prevalent and is associated with significant adverse outcomes both through liver-specific morbidity and mortality but, perhaps more important, through adverse cardiovascular and metabolic outcomes. It is closely associated with type 2 diabetes and obesity, and both of these conditions drive progressive disease toward the more advanced stages. The mechanisms that govern hepatic lipid accumulation and the predisposition to inflammation and fibrosis are still not fully understood but reflect a complex interplay between metabolic target tissues including adipose and skeletal muscle, and immune and inflammatory cells. The ability to make an accurate assessment of disease stage (that relates to clinical outcome) can also be challenging. While liver biopsy is still regarded as the gold-standard investigative tool, there is an extensive literature on the search for novel noninvasive biomarkers and imaging modalities that aim to accurately reflect the stage of underlying disease. Finally, although no therapies are currently licensed for the treatment of NAFLD, there are interventions that appear to have proven efficacy in randomized controlled trials as well as an extensive emerging therapeutic landscape of new agents that target many of the fundamental pathophysiological processes that drive NAFLD. It is highly likely that over the next few years, new treatments with a specific license for the treatment of NAFLD will become available.

Rifaximin prevents ethanol-induced liver injury in obese KK-Ay mice through modulation of small intestinal microbiota signature

Exacerbation of alcoholic hepatitis (AH) with comorbid metabolic syndrome is an emerging clinical problem, where microbiota plays a profound role in the pathogenesis. Here, we investigated the effect of rifaximin (RFX) on liver injury following chronic-binge ethanol (EtOH) administration in KK-A^y mice, a rodent model of metabolic syndrome. Female, 8-wk-old KK-A^y mice were fed Lieber-DeCarli diet (5% EtOH) for 10 days, following a single EtOH gavage (4 g/kg body wt). Some mice were given RFX (0.1 g/L, in liquid diet) orally. Small intestinal contents were collected from mice without binge. Intestinal microbiota was quantified using aerobic and anaerobic culturing techniques and further analyzed by 16S rRNA sequencing in detail. EtOH feeding/binge caused hepatic steatosis, oxidative stress, and induction of inflammatory cytokines in KK-A^y mice, which were markedly prevented by RFX treatment. Hepatic mRNA levels for cluster of differentiation 14, Toll-like receptor (TLR) 4, TLR2, and NADPH oxidase 2 were increased following EtOH feeding/binge, and administration of RFX completely suppressed their increase. The net amount of small intestinal bacteria was increased over threefold after chronic EtOH feeding as expected; however, RFX did not prevent this net increase. Intriguingly, the profile of small intestinal microbiota was dramatically changed following EtOH feeding in the order level, where the Erysipelotrichales predominated in the relative abundance. In sharp contrast, RFX drastically blunted the EtOH-induced increases in the Erysipelotrichales almost completely, with increased proportion of the Bacteroidales. In conclusion, RFX prevents AH through modulation of small intestinal microbiota/innate immune responses in obese KK-A^y mice.NEW & NOTEWORTHY Here we demonstrated that rifaximin (RFX) prevents chronic-binge ethanol (EtOH)-induced steatohepatitis in KK-A^y mice. Chronic EtOH feeding caused small intestinal bacterial overgrowth, with drastic alteration in the microbiota profile predominating the order Erysipelotrichales. RFX minimized this EtOH induction in Erysipelotrichales with substitutive increases in Bacteroidales. RFX also prevented EtOH-induced increases in portal lipopolysaccharide, and hepatic cluster of differentiation 14, toll-like receptor (TLR) 2, and TLR4 mRNA levels, suggesting the potential involvement of microbiota-related innate immune responses.

Chalcone Derivative L6H21 Reduces EtOH + LPS-Induced Liver Injury Through Inhibition of NLRP3 Inflammasome Activation

BACKGROUND

Chronic alcohol intake increases circulating endotoxin levels causing excessive inflammation that aggravates the liver injury. (E)-2,3-dimethoxy-4'-methoxychalcone (L6H21), a derivative of chalcone, has been found to inhibit inflammation in cardiac diseases and nonalcoholic fatty liver disease. However, the use of L6H21 in alcoholic liver disease to inhibit exotoxin-associated inflammation has not been explored. In this study, we examined the effects of L6H21 on EtOH + LPS-induced hepatic inflammation, steatosis, and liver injury and investigated the underlying mechanisms.

METHODS

C57BL6 mice were treated with 5% EtOH for 10 days, and LPS was given to the mice 6 hours before sacrificing. One group of mice was supplemented with L6H21 with EtOH and LPS. RAW264.7 cells were used to analyze the effects of L6H21 on macrophage activation.

RESULTS

EtOH + LPS treatment significantly increased hepatic steatosis and serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), which were reduced by L6H21 treatment. EtOH + LPS treatment increased hepatic inflammation, as shown by the increased hepatic protein levels of Toll-like receptor-4, p65, and p-IκB, and increased oxidative stress, as shown by protein carbonyl levels and reactive oxygen species formation, which were reduced by L6H21 treatment. In addition, L6H21 treatment markedly inhibited EtOH + LPS-elevated hepatic protein levels of NLRP3, cleaved caspase-1, cleaved IL-1β, and caspase-1-associated apoptosis.

CONCLUSIONS

Our results demonstrate that L6H21 treatment inhibits EtOH + LPS-induced liver steatosis and injury through suppression of NLRP3 inflammasome activation. L6H21 may be used as an alternative strategy for ALD prevention/treatment.

Sparstolonin B (SsnB) attenuates liver fibrosis via a parallel conjugate pathway involving P53-P21 axis, TGF-beta signaling and focal adhesion that is TLR4 dependent

SsnB previously showed a promising role to lessen liver inflammation observed in a mouse model of NAFLD. Since NAFLD can progress to fibrosis, studies were designed to unravel its role in attenuating NAFLD associated fibrosis. Using both in vivo and in vitro approaches, the study probed the possible mechanisms that underlined the role of SsnB in mitigating fibrosis. Mechanistically, SsnB, a TLR4 antagonist, decreased TLR4-PI3k akt signaling by upregulating PTEN protein expression. It also decreased MDM2 protein activation and increased p53 and p21 gene and protein expression. SsnB also downregulated pro-fibrogenic hedgehog signaling pathway, inhibited hepatic stellate cell proliferation and induced apoptosis in hepatic stellate cells, a mechanism that was LPS dependent. Further, SsnB decreased fibrosis by antagonizing TLR4 induced TGFβ signaling pathway. Alternatively, SsnB augmented BAMBI (a TGFβ pseudo-receptor) expression in mice liver by inhibiting TLR4 signaling pathway and thus reduced TGFβ signaling, resulting in decreased hepatic stellate cell activation and extracellular matrix deposition. In vitro experiments on human hepatic stellate cell line showed that SsnB increased gene and protein expression of BAMBI. It also decreased nuclear co-localization of phospho SMAD2/3 and SMAD4 protein and thus attenuated TGFβ signaling in vitro. We also observed a significant decrease in phosphorylation of SMAD2/3 protein, decreased STAT3 activation, alteration of focal adhesion protein and stress fiber disassembly upon SsnB administration in hepatic stellate cells which further confirmed the antagonistic effect of SsnB on TLR4-induced fibrogenesis.

Taurine Inhibits Kupffer Cells Activation Induced by Lipopolysaccharide in Alcoholic Liver Damaged Rats

Taurine, a β free amino-acid, takes various biological functions including maintain the normal hepatic structure and function. In this study, the regulation mechanism of taurine on lipopolysaccharide (LPS) induced activation of Kupffer cells (KC) in the liver of rats with alcoholic liver disease (ALD) were explored. Male wistar rats were intragastrically administered with alcohol and pyrazole, and ate high-fat diet in order to establish ALD model. Taurine were administered in drinking water simultaneous with and after ALD model establishment. The preventive trial was lasted for 12 weeks, while the curative trial was lasted for 4 weeks. Finally, blood and liver were collected in order to detect the concentrations of plasma LPS and hepatic tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Hepatic total RNA were extracted, gene expressions of LPS binding protein (LBP), leukocyte differentiation antigen 14 (CD14), toll-like receptors (TLR4), nuclear transcription factor (NF-κB) and TNF-α were detected by semi-quantitative RT-PCR. The results showed significant elevated levels of plasma LPS, hepatic TNF-α, IL-1β and IL-6 in ALD rats (P < 0.05), and heightened gene expressions of LBP, CD14, TLR4, NF-κB and TNF-α (P < 0.05); Taurine no matter administered preventively or curatively can reduce the levels of plasma LPS, hepatic TNF-α, IL-1β, IL-6, and down-regulate the gene expressions of LBP, CD14, TLR4, NF-κB and TNF-α. The results demonstrated that taurine can prevent and cure ALD by reducing the production and transformation of LPS as well as inhibiting the opening and the transmission of LPS induced KC activation and the downstream signaling pathway.

Compromised nutritional status in patients with end-stage liver disease: Role of gut microbiota

BACKGROUND

Patients with end-stage liver disease (ESLD) have a compromised nutritional status because of the liver crucial role in regulating metabolic homeostasis and energy balance.

DATA SOURCES

A systematic review of literature based on extensive relevant articles published from 2001 to 2017 in English in PubMed database was performed by searching keywords such as liver disease, non-alcoholic liver disease, alcoholic liver disease, malnutrition, epigenetics, gut microbiota, and probiotics.

RESULTS

Liver transplantation would be one eligible therapy for ESLD patients, even if, the clinical outcome is negatively influenced by malnutrition and/or infections. The malnutrition is a condition of nutrient imbalance with a high incidence in ESLD patients. An accurate evaluation of nutritional status could be fundamental for reducing complications and prolonging the survival of ESLD patients including those undergoing liver transplantation. In addition, the interaction among nutrients, diet and genes via epigenetics has emerged as a potential target to reduce the morbidity and mortality in ESLD patients. The malnutrition induces changes in gut microbiota causing dysbiosis with a probable translocation of bacteria and/or pathogen-derived factors from the intestine to the liver. Gut microbiota contribute to the progression of chronic liver diseases as well as hepatocellular carcinoma. The administration of probiotics modulating gut microbiota could improve all chronic liver diseases.

CONCLUSIONS

This review provides an update on malnutrition status linked to epigenetics and the potential benefit of some probiotics on the management of ESLD patients. In support of this view and to reveal the constant and growing interest in this field, some clinical trials are reported.

Polydatin attenuates diet-induced nonalcoholic steatohepatitis and fibrosis in mice

Scope: Non-alcoholic steatohepatitis (NASH) is characterized by lipid accumulation in hepatocytes and inflammatory cell infiltration. In view of the anti-oxidative and anti-inflammatory effects of polydatin, the current study aimed to investigate the pharmacological effects of polydatin on NASH and its related fibrosis. Methods: C57BL/6 mice were fed with methionine-choline deficient (MCD) diet to induce NASH and liver fibrosis, and treated with or without polydatin (5 mg/kg, every other day, i.p) for 4 weeks. HepG2 cells induced by palmitic acid (PA) were treated with polydatin. Results: The elevations of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), active caspase-3, TUNEL-positive cells, and triglyceride content were decreased by polydatin treatment. In addition, administration of polydatin to MCD-fed mice reduced oxidative stress by down-regulating NOX4 enzymes. Furthermore, the reduction in inflammation and CD68 macrophage activation correlated with inhibition of toll-like receptor (TLR)-4/NF-κB p65 signaling pathway by polydatin treatment. Polydatin also attenuated lipid accumulation, inflammation and apoptosis in HepG2 cells challenged by palmitic acid (PA) combined with or without lipopolysaccharide (LPS). Finally, the reduction of hepatic fibrosis by polydatin treatment corresponded to a reduction in hepatic gene expression of fibrosis markers. Conclusions: These results suggest that polydatin prevents NASH and fibrosis via inhibition of oxidative stress and inflammation, highlighting polydatin as a potential therapeutic agent for prevention and treatment of NASH.

Effect of celastrol on toll‑like receptor 4‑mediated inflammatory response in free fatty acid‑induced HepG2 cells

Toll-like receptor 4 (TLR4)-mediated immune and inflammatory signaling serves a pivotal role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Our previous study demonstrated that celastrol treatment was able to improve hepatic steatosis and inhibit the TLR4 signaling cascade pathway in type 2 diabetic rats. The present study aimed to investigate the effects of celastrol on triglyceride accumulation and inflammation in steatotic HepG2 cells, and the possible mechanisms responsible for the regulation of cellular responses following TLR4 gene knockdown by small interfering RNA (siRNA) in vitro. A cell model of hepatic steatosis was prepared by exposing the HepG2 cells to free fatty acid (FFA) in the absence or presence of celastrol. Intracellular triglycerides were visualized by Oil red O staining, and the TLR4/myeloid differentiation primary response 88 (MyD88)/nuclear factor-κB (NF-κB) signaling cascade pathway were investigated. To directly elucidate whether TLR4 was the blocking target of celastrol upon FFA exposure, the cellular response to inflammation was determined upon transfection with TLR4 siRNA. The results revealed that celastrol significantly reduced triglyceride accumulation in the steatotic HepG2 cells, and downregulated the expression levels of TLR4, MyD88 and phospho-NF-κBp65, as well as of the downstream inflammatory cytokines interleukin-1β and tumor necrosis factor α. Knockdown of TLR4 also alleviated FFA-induced inflammatory response. In addition, co-treatment with TLR4 siRNA and celastrol further attenuated the expression of inflammatory mediators. These results suggest that celastrol exerts its protective effect partly via inhibiting the TLR4-mediated immune and inflammatory response in steatotic HepG2 cells.

Positive Feedback Regulation between Transglutaminase 2 and Toll-Like Receptor 4 Signaling in Hepatic Stellate Cells Correlates with Liver Fibrosis Post Schistosoma japonicum Infection

Liver fibrosis induced by Schistosoma japonicum (Sj) infection is characterized by the accumulation of extracellular matrix (ECM). The activated and differentiated hepatic stellate cells (HSCs) are the predominant ECM-producing cell type in the liver. Toll-like receptor (TLR) 4 pathway activation plays a key role in mice liver fibrosis models induced by alcohol, biliary ligation, and carbon tetrachloride 4. In this work, we found that TLR4 pathway activation correlated with the severity of liver fibrosis post Sj infection. The TLR4 receptor inhibitor TAK242 reduced the extent of liver fibrosis. The increased expression of TLR4, α-smooth muscle actin (α-SMA), and cytoglobin was observed in the HSCs of mouse liver after Sj infection. In response to stimulation with either lipopolysaccharide or Sj's soluble egg antigen (SEA), high levels of TLR4 and α-SMA were induced in HSCs and were inhibited by TAK242 treatment. In previous work, we had reported that a high level of transglutaminase 2 (TGM2) is crucial for liver fibrosis post Sj infection. Herein, we found that TLR4 signaling also controlled Tgm2 expression. Inhibition of TGM2 activity by cystamine (CTM) in Sj-infected mice or in HSCs induced with all-trans-retinoic acid (ATRA) stimulation led to a lowered activation of TLR4 signaling and a reduced α-SMA expression. These results were confirmed by downregulating the Tgm2 gene by specific siRNA. These observations implied the presence of a positive feedback regulation between TGM2 and TLR4 signaling in HSCs that correlated with liver fibrosis post Sj infection. This novel connection between TGM2 and TLR4 pathway activation in liver fibrosis induced by Sj infection enhances our understanding of liver diseases.

Activation of autophagy attenuates EtOH-LPS-induced hepatic steatosis and injury through MD2 associated TLR4 signaling

Autophagy serves as a protective mechanism to degrade damaged organelles and proteins. Acute alcohol exposure is known to activate the hepatic autophagy response, whereas chronic alcohol exposure slows autophagosome formation along with an elevation of gut-derived endotoxin. In the current study, we examined whether lipopolysaccharide (LPS) administration decreased autophagic response in the liver of mice treated by short-term alcohol and whether activation of autophagy by rapamycin attenuates EtOH-LPS-induced liver steatosis and injury. We demonstrated that ten-day alcohol feeding primed the liver to LPS-induced lipid accumulation and liver injury with significantly increased hepatic steatosis and serum AST level as well as hepatic cellular NF-κB activation. LPS increased alcohol-mediated reactive oxygen species (ROS) formation while reducing autophagy activation. These deleterious effects were attenuated by rapamycin administration in mice. The protective effects of rapamycin are associated with decreased cellular MD2/TLR4 expression and interaction in Raw264.7 cells. Taken together, our results demonstrated that enhanced gut-derived LPS decreases the hepatic autophagosome numbers in response to alcohol exposure, and activation of autophagy by rapamycin protects from EtOH-LPS-induced liver injury, probably through reduced macrophage expression and interaction of TLR4/MD2 signaling complex.

Pathophysiology and Management of Alcoholic Liver Disease: Update 2016

Alcoholic liver disease (ALD) is a leading cause of cirrhosis, liver cancer, and acute and chronic liver failure and as such causes significant morbidity and mortality. While alcohol consumption is slightly decreasing in several European countries, it is rising in others and remains high in many countries around the world. The pathophysiology of ALD is still incompletely understood but relates largely to the direct toxic effects of alcohol and its main intermediate, acetaldehyde. Recently, novel putative mechanisms have been identified in systematic scans covering the entire human genome and raise new hypotheses on previously unknown pathways. The latter also identify host genetic risk factors for significant liver injury, which may help design prognostic risk scores. The diagnosis of ALD is relatively easy with a panel of well-evaluated tests and only rarely requires a liver biopsy. Treatment of ALD is difficult and grounded in abstinence as the pivotal therapeutic goal; once cirrhosis is established, treatment largely resembles that of other etiologies of advanced liver damage. Liver transplantation is a sound option for carefully selected patients with cirrhosis and alcoholic hepatitis because relapse rates are low and prognosis is comparable to other etiologies. Still, many countries are restrictive in allocating donor livers for ALD patients. Overall, few therapeutic options exist for severe ALD. However, there is good evidence of benefit for only corticosteroids in severe alcoholic hepatitis, while most other efforts are of limited efficacy. Considering the immense burden of ALD worldwide, efforts of medical professionals and industry partners to develop targeted therapies in ALF has been disappointingly low.

Protective effects of recombinant human cytoglobin against chronic alcohol-induced liver disease in vivo and in vitro

Alcoholic liver disease (ALD) is an important worldwide public health issue with no satisfying treatment available since now. Here we explore the effects of recombinant human cytoglobin (rhCygb) on chronic alcohol-induced liver injury and the underlying mechanisms. In vivo studies showed that rhCygb was able to ameliorate alcohol-induced liver injury, significantly reversed increased serum index (ALT, AST, TG, TC and LDL-C) and decreased serum HDL-C. Histopathology observation of the liver of rats treated with rhCygb confirmed the biochemical data. Furthermore, rhCygb significantly inhibited Kupffer cells (KCs) proliferation and TNF-α expression in LPS-induced KCs. rhCygb also inhibited LPS-induced NADPH oxidase activity and ROS, NO and O₂•^- generation. These results collectively indicate that rhCygb exert the protective effect on chronic alcohol-induced liver injury through suppression of KC activation and oxidative stress. In view of its anti-oxidative stress and anti-inflammatory features, rhCygb might be a promising candidate for development as a therapeutic agent against ALD.

TRIF Differentially Regulates Hepatic Steatosis and Inflammation/Fibrosis in Mice

BACKGROUND & AIMS

Toll-like receptor 4 (TLR4) signaling is activated through 2 adaptor proteins: MyD88 and TIR-domain containing adaptor-inducing interferon-β (TRIF). TLR4 and MyD88 are crucial in nonalcoholic steatohepatitis (NASH) and fibrosis. However, the role of TRIF in TLR4-mediated NASH and fibrosis has been elusive. This study investigated the differential roles of TRIF in hepatic steatosis and inflammation/fibrosis.

METHODS

A choline-deficient amino acid defined (CDAA) diet was used for the mouse NASH model. On this diet, the mice develop hepatic steatosis, inflammation, and fibrosis. TLR4 wild-type and TLR4^-/- bone marrow chimeric mice and TRIF^-/- mice were fed CDAA or a control diet for 22 weeks. Hepatic steatosis, inflammation, and fibrosis were examined.

RESULTS

In the CDAA diet-induced NASH, the mice with wild-type bone marrow had higher alanine aminotransferase and hepatic tumor necrosis factor levels than the mice with TLR4^-/- bone marrow. The nonalcoholic fatty liver disease activity score showed that both wild-type and TLR4^-/- bone marrow chimeras had reduced hepatic steatosis, and that both types of chimeras had similar levels of inflammation and hepatocyte ballooning to whole-body wild-type mice. Notably, wild-type recipients showed more liver fibrosis than TLR4^-/- recipients. Although TRIF^-/- mice showed reduced hepatic steatosis, these mice showed more liver injury, inflammation, and fibrosis than wild-type mice. TRIF^-/- stellate cells and hepatocytes produced more C-X-C motif chemokine ligand 1 (CXCL1) and C-C motif chemokine ligand than wild-type cells in response to lipopolysaccharide. Consistently, TRIF^-/- mice showed increased CXCL1 and CCL3 expression along with neutrophil and macrophage infiltration, which promotes liver inflammation and injury.

CONCLUSIONS

In TLR4-mediated NASH, different liver cells have distinct roles in hepatic steatosis, inflammation, and fibrosis. TRIF promotes hepatic steatosis but it inhibits injury, inflammation, and fibrosis.

Inhibition of spleen tyrosine kinase activation ameliorates inflammation, cell death, and steatosis in alcoholic liver disease

The spectrum of alcoholic liver disease (ALD) is a major cause of mortality with limited therapies available. Because alcohol targets numerous signaling pathways in hepatocytes and in immune cells, the identification of a master regulatory target that modulates multiple signaling processes is attractive. In this report, we assessed the role of spleen tyrosine kinase (SYK), a nonreceptor tyrosine kinase, which has a central modulatory role in multiple proinflammatory signaling pathways involved in the pathomechanism of ALD. Using mouse disease models that represent various phases in the progression of human ALD, we found that alcohol, in all of these models, induced SYK activation in the liver, both in hepatocytes and liver mononuclear cells. Furthermore, significant SYK activation also occurred in liver samples and peripheral blood mononuclear cells of patients with ALD/alcoholic hepatitis compared to controls. Functional inhibition of SYK activation in vivo abrogated alcohol-induced hepatic neutrophil infiltration, resident immune cell activation, as well as inflammasome and extracellular signal-regulated kinase 1 and 2-mediated nuclear factor kappa B activation in mice. Strikingly, inhibition of SYK activation diminished alcohol-induced hepatic steatosis and interferon regulatory factor 3-mediated apoptosis.

CONCLUSION

Our data demonstrate a novel, functional, and multicellular role for SYK phosphorylation in modulating immune cell-driven liver inflammation, hepatocyte cell death, and steatosis at different stages of ALD. These novel findings highlight SYK as a potential multifunctional target in the treatment of alcoholic steatohepatitis. (Hepatology 2016;64:1057-1071).

Genetic Influences on the Development of Fibrosis in Crohn's Disease

Fibrostenotic strictures are an important complication in patients with Crohn’s disease (CD), very often necessitating surgery. This fibrotic process develops in a genetically susceptible individual and is influenced by an interplay with environmental, immunological, and disease-related factors. A deeper understanding of the genetic factors driving this fibrostenotic process might help to unravel the pathogenesis, and ultimately lead to development of new, anti-fibrotic therapy. Here, we review the genetic factors that have been associated with the development of fibrosis in patients with CD, as well as their potential pathophysiological mechanism(s). We also hypothesize on clinical implications, if any, and future research directions.

Innate Immunity and Inflammation in NAFLD/NASH

Inflammation and hepatocyte injury and death are the hallmarks of nonalcoholic steatohepatitis (NASH), the progressive form of nonalcoholic fatty liver disease (NAFLD), which is a currently burgeoning public health problem. Innate immune activation is a key factor in triggering and amplifying hepatic inflammation in NAFLD/NASH. Thus, identification of the underlying mechanisms by which immune cells in the liver recognize cell damage signals or the presence of pathogens or pathogen-derived factors that activate them is relevant from a therapeutic perspective. In this review, we present new insights into the factors promoting the inflammatory response in NASH including sterile cell death processes resulting from lipotoxicity in hepatocytes as well as into the altered gut-liver axis function, which involves translocation of bacterial products into portal circulation as a result of gut leakiness. We further delineate the key immune cell types involved and how they recognize both damage-associated molecular patterns or pathogen-associated molecular patterns through binding of surface-expressed pattern recognition receptors, which initiate signaling cascades leading to injury amplification. The relevance of modulating these inflammatory signaling pathways as potential novel therapeutic strategies for the treatment of NASH is summarized.

Sparstolonin B attenuates early liver inflammation in experimental NASH by modulating TLR4 trafficking in lipid rafts via NADPH oxidase activation

Although significant research data exist on the pathophysiology of nonalcoholic steatohepatitis (NASH), finding an efficient treatment regimen for it remains elusive. The present study used sparstolonin B (SsnB), a novel TLR4 antagonist derived from the Chinese herb Sparganium stoloniferum, as a possible drug to mitigate early inflammation in NASH. This study used an early steatohepatitic injury model in high-fat-fed mice with CYP2E1-mediated oxidative stress as a second hit. SsnB was administered for 1 wk along with bromodichloromethane (BDCM), an inducer of CYP2E1-mediated oxidative stress. Results showed that SsnB administration attenuated inflammatory morphology and decreased elevation of the liver enzyme alanine aminotransferase (ALT). Mice administered SsnB also showed decreased mRNA expression of proinflammatory cytokines TNF-α, IFN-γ, IL-1β, and IL-23, while protein levels of both TNF-α and IL-1β were significantly decreased. SsnB significantly decreased Kupffer cell activation as evidenced by reduction in CD68 and monocyte chemoattractant protein-1 (MCP1) mRNA and protein levels with concomitant inhibition of macrophage infiltration in the injured liver. Mechanistically, SsnB decreased TLR4 trafficking to the lipid rafts, a phenomenon described by the colocalization of TLR4 and lipid raft marker flotillin in tissues and immortalized Kupffer cells. Since we have shown previously that NADPH oxidase drives TLR4 trafficking in NASH, we studied the role of SsnB in modulating this pathway. SsnB prevented NADPH oxidase activation in vivo and in vitro as indicated by decreased peroxynitrite formation. In summary, the present study reports a novel use of the TLR4 antagonist SsnB in mitigating inflammation in NASH and in parallel shows a unique molecular mechanism of decreasing nitrative stress.

Immunology in the liver--from homeostasis to disease

The liver is a central immunological organ with a high exposure to circulating antigens and endotoxins from the gut microbiota, particularly enriched for innate immune cells (macrophages, innate lymphoid cells, mucosal-associated invariant T (MAIT) cells). In homeostasis, many mechanisms ensure suppression of immune responses, resulting in tolerance. Tolerance is also relevant for chronic persistence of hepatotropic viruses or allograft acceptance after liver transplantation. The liver can rapidly activate immunity in response to infections or tissue damage. Depending on the underlying liver disease, such as viral hepatitis, cholestasis or NASH, different triggers mediate immune-cell activation. Conserved mechanisms such as molecular danger patterns (alarmins), Toll-like receptor signalling or inflammasome activation initiate inflammatory responses in the liver. The inflammatory activation of hepatic stellate and Kupffer cells results in the chemokine-mediated infiltration of neutrophils, monocytes, natural killer (NK) and natural killer T (NKT) cells. The ultimate outcome of the intrahepatic immune response (for example, fibrosis or resolution) depends on the functional diversity of macrophages and dendritic cells, but also on the balance between pro-inflammatory and anti-inflammatory T-cell populations. As reviewed here, tremendous progress has helped to understand the fine-tuning of immune responses in the liver from homeostasis to disease, indicating promising targets for future therapies in acute and chronic liver diseases.

Preventive effects of phenylethanol glycosides from Cistanche tubulosa on bovine serum albumin-induced hepatic fibrosis in rats

BACKGROUND

Cistanche tubulosa is a traditional Chinese herbal medicine that is widely used for regulating immunity. Phenyl ethanol glycosides (CPhGs) from this plant are the primarily efficacious materials. This aim of this study was to evaluate the preventive and therapeutic effects of CPhGs on BSA-induced hepatic fibrosis in rats and related molecular mechanisms involving hepatic stellate cells. Biejiarangan (BJRG), another traditional Chinese herbal medicine, was used as a positive control.

METHODS

In in vivo experiments, 75 SD rats were randomly divided into 6 groups: normal (distilled water-treated), model (BSA-treated), positive drug (BSA-treated + BJRG 600 mg/kg/day), and BSA-treated + CPhGs (125, 250, and 500 mg/kg/day) groups. The liver and spleen indices, serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), hexadecenoic acid (HA), laminin (LN), type III procollagen (PCIII), type IV collagen (IV-C), hydroxyproline (Hyp), and transforming growth factor β 1 (TGF-β 1) were measured in rat livers. Histopathological grades for liver fibrosis were assessed for each group using H&E and Masson's trichrome staining. The expression of TGF-β 1, collagen I (Col-I) and collagen III (Col-III) were determined by an immunohistochemical staining method. These effects were further evaluated in vitro by determining expression levels of NF-κB p65 and Col-I by quantitative real-time PCR analyses. Col-I protein expression was also examined by western blotting.

RESULTS

All dose groups (125, 250, and 500 mg/kg/day) of CPhGs significantly reduced the liver and spleen index, decreased ALT, AST, HA, LN, PCIII, IV-C serum levels, TGF-β 1 content (P < 0.01, P < 0.01, and P < 0.01), and Hyp content. CPhGs also markedly alleviated the swelling of liver cells and effectively prevented hepatocyte necrosis and inflammatory cell infiltration. Immunohistochemical results showed that CPhGs significantly reduced the expression of TGF-β 1 (P < 0.01, P < 0.01, and P < 0.01), Col- I, and Col-III. The in vitro effects of CPhGs (100, 75, 50, and 25 ug/ml) on HSC-T6 showed that CPhGs significantly reduced mRNA expression of NF-κB p65 and Col-I, and CPhGs also downregulated Col-I protein expression.

CONCLUSIONS

CPhGs have a significant anti-hepatic fibrosis effect, and may be used as hepatoprotective agents for treatment of hepatic fibrosis.

Clinical and pathophysiological consequences of alterations in the microbiome in cirrhosis

Cirrhosis is a major cause of mortality worldwide. Exponential rises in prevalence have been observed secondary to increases in obesity and alcohol consumption. Multiple lines of evidence implicate gut-derived bacteria and bacterial ligands as a central driver of pathogenesis. Recent developments in culture-independent techniques have facilitated a more accurate description of microbiome composition in cirrhosis and led to the description of measures of dysbiosis shown to be associated with disease. More importantly, metagenomic studies are adding to an understanding of the functional contribution of the microbiota and may prove to be a more clinically relevant biomarker than phylogenetic studies. Much like other dysbiotic states such as inflammatory bowel disease, the microbiota in cirrhosis is characterized by a low microbial and genetic diversity. Therapeutic strategies to diminish this process are currently limited to selective intestinal decontamination with antibiotics. This review summarizes the available data and develops a framework for the use of current and future treatment strategies to diminish the consequences of dysbiosis in cirrhosis. Interventional strategies to bind bacterial products in the gut lumen and blood, and modulate the magnitude of host sensing mechanisms remain an unmet clinical need. A greater understanding of the host-microbiota interaction in cirrhosis is of key importance to inform future interventional strategies to diminish the currently escalating burden of the disease.

Alterations in Activation, Cytotoxic Capacity and Trafficking Profile of Peripheral CD8 T Cells in Young Adult Binge Drinkers

Background

Excess of alcohol consumption is a public health problem and has documented effects on the immune system of humans and animals. Animal and in vitro studies suggest that alcohol abuse changes CD8 T cell (CD8) characteristics, however it remains unknown if the CD8 profile of binge drinkers is different in terms of activation, trafficking and cytotoxic capacity.

Aim

To analyze the peripheral CD8 cytotoxic capacity, activation and trafficking phenotypic profile of Mexican young adults with regard to alcohol consumption pattern.

Methods

55 Mexican young adults were stratified as Light (20), Intermediate (18) or Binge drinkers (17) according to their reported alcohol consumption pattern. Blood samples were obtained and hematic biometry and liver enzyme analysis were performed. Peripheral CD8 profile was established by expression of Granzyme B (GB), CD137, CD127, CD69, TLR4, PD1, CCR2, CCR4, CCR5 and CXCR4 by FACS. Data was analyzed by ANOVA, posthoc DMS and Tamhane, and principal component analysis (PCA) with varimax rotation, p<0.05.

Results

The Binge drinking group showed increased γGT together with increased expression of CD69 and reduced expression of TLR4, PD1, CCR2 and CXCR4 in peripheral CD8 cells. Other parameters were also specific to Binge drinkers. PCA established 3 factors associated with alcohol consumption: “Early Activation” represented by CD69 and TLR4 expression in the CD8 population; “Effector Activation” by CD69 expression in CD8 CD127⁺CD137⁺ and CD8 CD25⁺ CD137⁺; and Trafficking by CXCR4 expression on total CD8 and CD8 GB⁺CXCR4⁺, and CCR2 expression on total CD8. Binge drinking pattern showed low expression of Early Activation and Trafficking factors while Light drinking pattern exhibited high expression of Effector Activation factor.

Conclusions

Alcohol consumption affects the immune phenotype of CD8 cells since binge drinking pattern was found to be associated with high CD69 and low TLR4, CXCR4 and CCR2 expression, which suggest recent activation, decreased sensitivity to LPS and lower migration capacity in response to chemokines SDF-1 and MCP-1. These results indicate that a binge-drinking pattern of alcohol consumption may induce an altered immune profile that could be related with liver damage and the increased susceptibility to infection reported to this behavior.

Inflammasome activation and function in liver disease

Inflammation contributes to the pathogenesis of most acute and chronic liver diseases. Inflammasomes are multiprotein complexes that can sense danger signals from damaged cells and pathogens and assemble to mediate caspase-1 activation, which proteolytically activates the cytokines IL-1β and IL-18. In contrast to other inflammatory responses, inflammasome activation uniquely requires two signals to induce inflammation, therefore setting an increased threshold. IL-1β, generated upon caspase-1 activation, provides positive feed-forward stimulation for inflammatory cytokines, thereby amplifying inflammation. Inflammasome activation has been studied in different human and experimental liver diseases and has been identified as a major contributor to hepatocyte damage, immune cell activation and amplification of liver inflammation. In this Review, we discuss the different types of inflammasomes, their activation and biological functions in the context of liver injury and disease progression. Specifically, we focus on the triggers of inflammasome activation in alcoholic steatohepatitis and NASH, chronic HCV infection, ischaemia-reperfusion injury and paracetamol-induced liver injury. The application and translation of these discoveries into therapies promises novel approaches in the treatment of inflammation in liver disease.

NADPH Oxidase-Derived Peroxynitrite Drives Inflammation in Mice and Human Nonalcoholic Steatohepatitis via TLR4-Lipid Raft Recruitment

The molecular events that link NADPH oxidase activation and the induction of Toll-like receptor (TLR)-4 recruitment into hepatic lipid rafts in nonalcoholic steatohepatitis (NASH) are unclear. We hypothesized that in liver, NADPH oxidase activation is key in TLR4 recruitment into lipid rafts, which in turn up-regulates NF-κB translocation to the nucleus and subsequent DNA binding, leading to NASH progression. Results from confocal microscopy showed that liver from murine and human NASH had NADPH oxidase activation, which led to the formation of highly reactive peroxynitrite, as shown by 3-nitrotyrosine formation in diseased liver. Expression and recruitment of TLR4 into the lipid rafts were significantly greater in rodent and human NASH. The described phenomenon was NADPH oxidase, p47phox, and peroxynitrite dependent, as liver from p47phox-deficient mice and from mice treated with a peroxynitrite decomposition catalyst [iron(III) tetrakis(p-sulfonatophenyl)porphyrin] or a peroxynitrite scavenger (phenylboronic acid) had markedly less Tlr4 recruitment into lipid rafts. Mechanistically, peroxynitrite-induced TLR4 recruitment was linked to increased IL-1β, sinusoidal injury, and Kupffer cell activation while blocking peroxynitrite-attenuated NASH symptoms. The results strongly suggest that NADPH oxidase-mediated peroxynitrite drove TLR4 recruitment into hepatic lipid rafts and inflammation, whereas the in vivo use of the peroxynitrite scavenger phenylboronic acid, a novel synthetic molecule having high reactivity with peroxynitrite, attenuates inflammatory pathogenesis in NASH.

Probiotics (Lactobacillus rhamnosus R0011 and acidophilus R0052) reduce the expression of toll-like receptor 4 in mice with alcoholic liver disease

OBJECTIVE

The role of lipopolysaccharide (LPS) and toll-like receptor 4 (TLR 4) in the pathogenesis of alcoholic liver disease (ALD) has been widely established. We evaluated the biological effects of probiotics (Lactobacillus rhamnosus R0011 and acidophilus R0052), KRG (Korea red ginseng), and urushiol (Rhus verniciflua Stokes) on ALD, including their effects on normal and high-fat diet in mice.

METHODS

One hundred C57BL/6 mice were classified into normal (N) and high-fat diet (H) groups. Each group was divided into 5 sub-groups: control, alcohol, alcohol+probiotics, alcohol+KRG, and alcohol+urushiol. A liver function test, histology, electron-microscopy, interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-10, and TLR 4 were evaluated and compared.

RESULTS

In the N group, probiotics, KRG, and urushiol significantly reduced levels of TNF-α (12.3±5.1, 13.4±3.9, and 12.1±4.3 vs. 27.9±15.2 pg/mL) and IL-1β (108.4±39.4, 75.0±51.0, and 101.1±26.8 vs. 162.4±37.5 pg/mL), which were increased by alcohol. Alcohol-induced TLR 4 expression was reduced by probiotics and urushiol (0.7±0.2, and 0.8±0.1 vs. 1.0±0.3, p<0.001). In the H group, IL-10 was significantly increased by probiotics and KRG, compared with alcohol (25.3±15.6 and 20.4±6.2 vs. 7.6±5.6 pg/mL) and TLR 4 expression was reduced by probiotics (0.8±0.2 vs. 1.0±0.3, p = 0.007).

CONCLUSIONS

Alcohol-induced TLR 4 expression was down-regulated by probiotics in the normal and high-fat diet groups. Probiotics, KRG, and urushiol might be effective in the treatment of ALD by regulating the gut-liver axis.