Steatosis induced CCL5 contributes to early-stage liver fibrosis in nonalcoholic fatty liver disease progress

Histone methyltransferase Suv39h1 regulates hepatic stellate cell activation and is targetable in liver fibrosis

OBJECTIVE

Liver fibrosis is a prelude to a host of end-stage liver diseases. Hepatic stellate cells (HSCs), switching from a quiescent state to myofibroblasts, are the major source for excessive production of extracellular matrix proteins. In the present study, we investigated the role of Suv39h1, a lysine methyltransferase, in HSC-myofibroblast transition and the implication in liver fibrosis.

DESIGN

HSC-specific or myofibroblast-specific Suv39h1 deletion was achieved by crossbreeding the Suv39h1 f/f mice to the Lrat-Cre mice or the Postn-CreERT2 mice. Liver fibrosis was induced by CCl4 injection or bile duct ligation.

RESULTS

We report that Suv39h1 expression was universally upregulated during HSC-myofibroblast transition in different cell and animal models of liver fibrosis and in human cirrhotic liver tissues. Consistently, Suv39h1 knockdown blocked HSC-myofibroblast transition in vitro. HSC-specific or myofibroblast-specific deletion of Suv39h1 ameliorated liver fibrosis in mice. More importantly, Suv39h1 inhibition by a small-molecule compound chaetocin dampened HSC-myofibroblast transition in cell culture and mitigated liver fibrosis in mice. Mechanistically, Suv39h1 bound to the promoter of heme oxygenase 1 (HMOX1) and repressed HMOX1 transcription. HMOX1 depletion blunted the effects of Suv39h1 inhibition on HSC-myofibroblast transition in vitro and liver fibrosis in vivo. Transcriptomic analysis revealed that HMOX1 might contribute to HSC-myofibroblast transition by modulating retinol homeostasis. Finally, myofibroblast-specific HMOX1 overexpression attenuated liver fibrosis in both a preventive scheme and a therapeutic scheme.

CONCLUSIONS

Our data demonstrate a previously unrecognised role for Suv39h1 in liver fibrosis and offer proof-of-concept of its targetability in the intervention of cirrhosis.

Combined with multiplex and network analysis to reveal the key genes and mechanisms of nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) has become a significant cause of chronic liver disease in developed countries, as a result of the worldwide trend of obesity and associated metabolic syndrome. Obesity and high-fat diet (HFD) are very common in patients with NAFLD. However, how to screen out key differentially expressed genes (DEGs) is a challenging task. The purpose of this study is to study the screen of key genes and pathways of HFD on the formation process of non-alcoholic fatty liver through network pharmacological analysis.

METHODS

In this study, 173 genes associated with NAFLD were collected from the Gene Expression Omnibus (GEO) database. To find significant genes and pathways, combine network clustering analysis, topology analysis, and pathway analysis.

RESULTS

The results showed that there were four key signaling pathways related to HFD, including complement cascade, Atorvastatin ADME, Asthma and Aflatoxin activation and detoxification. In addition, we identified six representative key genes, including Ccl5, Tlr2, Cd274, Cxcl10, Cxcl9 and Cd74, and screened three intersecting genes in Mus musculus and Homo sapiens sample, including C3, F2 and C7.

CONCLUSIONS

In conclusion, our study constructed the NAFLD gene regulatory network of C57BL/6J mice for the first time and jointly analyzed the Mus musculus samples and Homo sapiens samples. It provides new insights for identifying potential biomarkers and valuable therapeutic clues, and puts forward a new method for web-based research. These findings may provide potential targets for early diagnosis, effective therapy and prognostic markers of NAFLD.

C-C motif chemokine CCL11 is a novel regulator and a potential therapeutic target in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is characterised by accelerated lipid deposition, aberrant inflammation, and excessive extracellular matrix production in the liver. Short of effective intervention, NAFLD can progress to cirrhosis and hepatocellular carcinoma. In the present study we investigated the involvement of the C-C motif ligand 11 (CCL11) in NAFLD pathogenesis.

METHODS

NAFLD was induced by feeding mice with a high-fat high-carbohydrate diet. CCL11 targeting was achieved by genetic deletion or pharmaceutical inhibition. The transcriptome was analysed using RNA-seq.

RESULTS

We report that CCL11 expression was activated at the transcription level by free fatty acids (palmitate) in hepatocytes. CCL11 knockdown attenuated whereas CCL11 treatment directly promoted production of pro-inflammatory/pro-lipogenic mediators in hepatocytes. Compared with wild-type littermates, CCL11 knockout mice displayed an ameliorated phenotype of NAFLD when fed a high-fat high-carbohydrate diet as evidenced by decelerated body weight gain, improved insulin sensitivity, dampened lipid accumulation, reduced immune cell infiltration, and weakened liver fibrosis. RNA-seq revealed that interferon regulatory factor 1 as a mediator of CCL11 induced changes in hepatocytes. Importantly, CCL11 neutralisation or antagonism mitigated NAFLD pathogenesis in mice. Finally, a positive correlation between CCL11 expression and NAFLD parameters was identified in human patients.

CONCLUSIONS

Our data suggest that CCL11 is a novel regulator of NAFLD and can be effectively targeted for NAFLD intervention.

IMPACT AND IMPLICATIONS

Non-alcoholic fatty liver disease (NAFLD) precedes cirrhosis and hepatocellular carcinoma. In this paper we describe the regulatory role of CCL11, a C-C motif ligand chemokine, in NAFLD pathogenesis. Our data provide novel insights and translational potential for NAFLD intervention.

Liquiritin Protects Against Cardiac Fibrosis After Myocardial Infarction by Inhibiting CCL5 Expression and the NF-κB Signaling Pathway

Purpose

Despite significant advances in interventional treatment, myocardial infarction (MI) and subsequent cardiac fibrosis remain major causes of high mortality worldwide. Liquiritin (LQ) is a flavonoid extract from licorice that possesses a variety of pharmacological properties. However, to our knowledge, the effects of LQ on myocardial fibrosis after MI have not been reported in detail. The aim of our research was to explore the potential role and mechanism of LQ in MI-induced myocardial damage.

Methods

The MI models were established by ligating the left anterior descending branch of the coronary artery. Next, rats were orally administered LQ once a day for 14 days. Biochemical assays, histopathological observations, ELISA, and Western blotting analyses were then conducted.

Results

LQ improved the heart appearance and ECG, decreased cardiac weight index and reduced levels of cardiac-specific markers such as CK, CK-MB, LDH, cTnI and BNP. Meanwhile, LQ reduced myocardial infarct size and improved hemodynamic parameters such as LVEDP, LVSP and ±dp/dt_max. Moreover, H&E staining showed that LQ attenuated the pathological damage caused by MI. Masson staining showed that LQ alleviated myocardial cell disorder and fibrosis while reducing collagen deposition. LQ also decreased the levels of oxidative stress and inflammation. Western blotting demonstrated that LQ significantly down-regulated the expressions of Collagen I, Collagen III, TGF-β1, MMP-9, α-SMA, CCL5, and p-NF-κB.

Conclusion

LQ protected against myocardial fibrosis following MI by improving cardiac function, and attenuating oxidative damage and inflammatory response, which may be associated with inhibition of CCL5 expression and the NF-κB pathway.

Single-cell transcriptomics reveals the role of Macrophage-Naïve CD4 + T cell interaction in the immunosuppressive microenvironment of primary liver carcinoma

Background

Liver carcinoma generally presents as an immunosuppressive microenvironment that promotes tumor evasion. The intercellular crosstalk of immune cells significantly influences the construction of an immunosuppressive microenvironment. This study aimed to investigate the important interactions between immune cells and their targeting drugs in liver carcinoma, by using single-cell and bulk transcriptomic data.

Methods

Single-cell and bulk transcriptomic data were retrieved from Gene Expression Omnibus (GSE159977, GSE136103, and GSE125449) and The Cancer Genome Atlas (TGCA-LIHC), respectively. Quality control, dimension reduction, clustering, and annotation were performed according to the Scanpy workflow based on Python. Cell–cell interactions were explored using the CellPhone database and CellChat. Trajectory analysis was executed using a partition-based graph abstraction method. The transcriptomic factors (TFs) were predicted using single-cell regulatory network inference and clustering (SCENIC). The target genes from TFs were used to establish a related score based on the TCGA cohort; this score was subsequently validated by survival, gene set enrichment, and immune cell infiltration analyses. Drug prediction was performed based on the Cancer Therapeutics Response Portal and PRISM Repurposing datasets.

Results

Thirty-one patients at four different states, including health, hepatitis, cirrhosis, and cancer, were enrolled in this study. After dimension reduction and clustering, twenty-two clusters were identified. Cell–cell interaction analyses indicated that macrophage-naive CD4 + T cell interaction significantly affect cancerous state. In brief, macrophages interact with naive CD4 + T cells via different pathways in different states. The results of SCENIC indicated that macrophages present in cancer cells were similar to those present during cirrhosis. A macrophage-naive CD4 + T cell (MNT) score was generated by the SCENIC-derived target genes. Based on the MNT score, five relevant drugs (inhibitor of polo-like kinase 1, inhibitor of kinesin family member 11, dabrafenib, ispinesib, and epothilone-b) were predicted.

Conclusions

This study reveals the crucial role of macrophage-naive CD4 + T cell interaction in the immunosuppressive microenvironment of liver carcinoma. Tumor-associated macrophages may be derived from cirrhosis and can initiate liver carcinoma. Predictive drugs that target the macrophage-naive CD4 + T cell interaction may help to improve the immunosuppressive microenvironment and prevent immune evasion. The relevant mechanisms need to be further validated in experiments and cohort studies.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03675-2.

CCAAT/Enhancer-Binding Proteins in Fibrosis: Complex Roles Beyond Conventional Understanding

CCAAT/enhancer-binding proteins (C/EBPs) are a family of at least six identified transcription factors that contain a highly conserved basic leucine zipper domain and interact selectively with duplex DNA to regulate target gene expression. C/EBPs play important roles in various physiological processes, and their abnormal function can lead to various diseases. Recently, accumulating evidence has demonstrated that aberrant C/EBP expression or activity is closely associated with the onset and progression of fibrosis in several organs and tissues. During fibrosis, various C/EBPs can exert distinct functions in the same organ, while the same C/EBP can exert distinct functions in different organs. Modulating C/EBP expression or activity could regulate various molecular processes to alleviate fibrosis in multiple organs; therefore, novel C/EBPs-based therapeutic methods for treating fibrosis have attracted considerable attention. In this review, we will explore the features of C/EBPs and their critical functions in fibrosis in order to highlight new avenues for the development of novel therapies targeting C/EBPs.

NADPH Oxidases Connecting Fatty Liver Disease, Insulin Resistance and Type 2 Diabetes: Current Knowledge and Therapeutic Outlook

Nonalcoholic fatty liver disease (NAFLD), characterized by ectopic fat accumulation in hepatocytes, is closely linked to insulin resistance and is the most frequent complication of type 2 diabetes mellitus (T2DM). One of the features connecting NAFLD, insulin resistance and T2DM is cellular oxidative stress. Oxidative stress refers to a redox imbalance due to an inequity between the capacity of production and the elimination of reactive oxygen species (ROS). One of the major cellular ROS sources is NADPH oxidase enzymes (NOX-es). In physiological conditions, NOX-es produce ROS purposefully in a timely and spatially regulated manner and are crucial regulators of various cellular events linked to metabolism, receptor signal transmission, proliferation and apoptosis. In contrast, dysregulated NOX-derived ROS production is related to the onset of diverse pathologies. This review provides a synopsis of current knowledge concerning NOX enzymes as connective elements between NAFLD, insulin resistance and T2DM and weighs their potential relevance as pharmacological targets to alleviate fatty liver disease.

PPAR-Targeted Therapies in the Treatment of Non-Alcoholic Fatty Liver Disease in Diabetic Patients

Peroxisome proliferator-activated receptors (PPAR), ligand-activated transcription factors of the nuclear hormone receptor superfamily, have been identified as key metabolic regulators in the liver, skeletal muscle, and adipose tissue, among others. As a leading cause of liver disease worldwide, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) cause a significant burden worldwide and therapeutic strategies are needed. This review provides an overview of the evidence on PPAR-targeted treatment of NAFLD and NASH in individuals with type 2 diabetes mellitus. We considered current evidence from clinical trials and observational studies as well as the impact of treatment on comorbid metabolic conditions such as obesity, dyslipidemia, and cardiovascular disease. Future areas of research, such as possible sexually dimorphic effects of PPAR-targeted therapies, are briefly reviewed.

Liver Fibrosis and MAFLD: From Molecular Aspects to Novel Pharmacological Strategies

Metabolic-associated fatty liver disease (MAFLD) is a new disease definition, and this nomenclature MAFLD was proposed to renovate its former name, non-alcoholic fatty liver disease (NAFLD). MAFLD/NAFLD have shared and predominate causes from nutrition overload to persistent liver damage and eventually lead to the development of liver fibrosis and cirrhosis. Unfortunately, there is an absence of effective treatments to reverse MAFLD/NAFLD-associated fibrosis. Due to the significant burden of MAFLD/NAFLD and its complications, there are active investigations on the development of novel targets and pharmacotherapeutics for treating this disease. In this review, we cover recent discoveries in new targets and molecules for antifibrotic treatment, which target pathways intertwined with the fibrogenesis process, including lipid metabolism, inflammation, cell apoptosis, oxidative stress, and extracellular matrix formation. Although marked advances have been made in the development of antifibrotic therapeutics, none of the treatments have achieved the endpoints evaluated by liver biopsy or without significant side effects in a large-scale trial. In addition to the discovery of new druggable targets and pharmacotherapeutics, personalized medication, and combinatorial therapies targeting multiple profibrotic pathways could be promising in achieving successful antifibrotic interventions in patients with MAFLD/NAFLD.

Role of placental inflammatory mediators and growth factors in patients with rheumatic diseases with a focus on systemic sclerosis

Objectives

Pregnancy in SSc is burdened with an increased risk of obstetric complications. Little is known about the underlying placental alterations. This study aimed to better understand pathological changes and the role of inflammation in SSc placentas. Leucocyte infiltration, inflammatory mediators and atypical chemokine receptor 2 (ACKR2) expression in SSc placentas were compared with those in other rheumatic diseases (ORD) and healthy controls (HC).

Methods

A case–control study was conducted on eight pregnant SSc patients compared with 16 patients with ORD and 16 HC matched for gestational age. Clinical data were collected. Placentas were obtained for histopathological analysis and immunohistochemistry (CD3, CD20, CD11c, CD68, ACKR2). Samples from four SSc, eight ORD and eight HC were analysed by qPCR for ACKR2 expression and by multiplex assay for cytokines, chemokines and growth factors involved in angiogenesis and inflammation.

Results

The number of placental CD3, CD68 and CD11 cells was significantly higher in patients affected by rheumatic diseases (SSc+ORD) compared with HC. Hepatocyte growth factor was significantly increased in the group of rheumatic diseases patients (SSc+ORD) compared with HC, while chemokine (C-C motif) ligand 5 (CCL5) was significantly higher in SSc patients compared with ORD and HC. CCL5 levels directly correlated with the number of all local inflammatory cells and higher levels were associated with histological villitis.

Conclusions

Inflammatory alterations characterize placentas from rheumatic disease patients and could predispose to obstetric complications in these subjects.

Single-cell RNA-seq reveals a critical role of novel pro-inflammatory EndMT in mediating adverse remodeling in coronary artery-on-a-chip

A three-dimensional microengineered human coronary artery-on-a-chip was developed for investigation of the mechanism by which low and oscillatory shear stress (OSS) induces pro-atherogenic changes. Single-cell RNA sequencing revealed that OSS induced distinct changes in endothelial cells (ECs) including pro-inflammatory endothelial-to-mesenchymal transition (EndMT). OSS promoted pro-inflammatory EndMT through the Notch1/p38 MAPK-NF-κB signaling axis. Moreover, OSS-induced EC phenotypic changes resulted in proliferation and extracellular matrix (ECM) protein up-regulation in smooth muscle cells (SMCs) through the RANTES-mediated paracrine mechanism. IL-37 suppressed OSS-induced pro-inflammatory EndMT and thereby abrogated SMC proliferation and ECM protein remodeling. Overall, this study provides insights into endothelial heterogeneity under atheroprone shear stress and identifies the mechanistic role of a novel EC subtype in promoting adverse vascular remodeling. Further, this study demonstrates that anti-inflammatory approach is capable of mitigating vascular pathobiology evoked by atheroprone shear stress.

Kaempferol Alleviates Steatosis and Inflammation During Early Non-Alcoholic Steatohepatitis Associated With Liver X Receptor α-Lysophosphatidylcholine Acyltransferase 3 Signaling Pathway

Background: Kaempferol (KP) has a variety of biological effects such as anti-inflammatory, anti-oxidant, anti-aging and cardiovascular protection. Whether KP has a therapeutic effect on non-alcoholic steatohepatitis (NASH), and the detailed mechanism is currently unclear. This study aims to explore the mechanism of KP in the treatment of NASH through in vivo and in vitro experiments.

Methods: 1) In vivo experiment: In the C57BL/6 NASH mice model induced by high fat diet (HFD), KP was administered by gavage at a dose of 20 mg/kg/day. 2) In vitro experiment: Palmitic acid/Oleic acid (PA/OA, 0.375/0.75 mM) was used to intervene HepG2 and AML12 cells to establish a steatosis cell model. Three concentrations of KP, low (20 μmol/L), medium (40 μmol/L) and high (60 μmol/L) were used in vitro. The mRNA and protein expression of related molecules involved in LXRα-LPCAT3-ERS pathway were detected using RT-qPCR and Western blot.

Results: In the NASH mouse model, KP can significantly reduce the expression of LXRα, LPCAT3 and ERS-related factors PERK, eIF2α, ATF6, ATF4, XBP1, CHOP, IRE1α and GRP78. In the PA/OA-induced cell model, KP could decrease the content of triglyceride and lipid droplets, and also decrease the expression of LXR α, LPCAT3 and ERS related factors PERK, eIF2α, ATF6, ATF4, XBP1, CHOP, IRE1α and GRP78.

Conclusion: KP may decrease the expression level of LXRα and LPCAT3, thus improve ERS and reduce hepatic steatosis and inflammation.

Mechanisms and disease consequences of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the leading chronic liver disease worldwide. Its more advanced subtype, nonalcoholic steatohepatitis (NASH), connotes progressive liver injury that can lead to cirrhosis and hepatocellular carcinoma. Here we provide an in-depth discussion of the underlying pathogenetic mechanisms that lead to progressive liver injury, including the metabolic origins of NAFLD, the effect of NAFLD on hepatic glucose and lipid metabolism, bile acid toxicity, macrophage dysfunction, and hepatic stellate cell activation, and consider the role of genetic, epigenetic, and environmental factors that promote fibrosis progression and risk of hepatocellular carcinoma in NASH.

Role of CC chemokine receptor 9 in the progression of murine and human non-alcoholic steatohepatitis

BACKGROUND & AIMS

The number of patients with non-alcoholic steatohepatitis (NASH) is increasing globally. Recently, specific chemokine receptors have garnered interest as therapeutic targets in NASH. This is the first report to examine the role of the C-C chemokine receptor 9 (CCR9)/C-C chemokine receptor ligand 25 (CCL25) axis, and to reveal its therapeutic potential in NASH.

METHODS

Patients with biopsy-proven non-alcoholic liver disease (NAFLD) were recruited and their serum and hepatic chemokine expression was examined. Furthermore, wild-type (WT) and Ccr9^-/- mice were fed a high-fat high-cholesterol (HFHC) diet for 24 weeks to establish NASH.

RESULTS

Serum CCL25, and hepatic CCR9 and CCL25 expression levels were increased in patients with NASH compared to healthy volunteers. Furthermore, Ccr9^-/- mice were protected from HFHC diet-induced NASH progression both serologically and histologically. Flow cytometry and immunohistochemistry analysis showed that CCR9⁺CD11b⁺ inflammatory macrophages accumulated in the inflamed livers of HFHC diet-fed mice, while the number was reduced in Ccr9^-/- mice. Consistent with human NASH livers, CCR9 was also expressed on hepatic stellate cells (HSCs) in mice with NASH, while CCR9-deficient HSCs showed less fibrogenic potential in vitro. Administration of a CCR9 antagonist hampered further fibrosis progression in mice with NASH, supporting its potential clinical application. Finally, we showed that CCR9 blockade attenuated the development of NAFLD-related hepatocellular carcinoma in HF diet-fed mice injected with diethylnitrosamine.

CONCLUSIONS

These results highlight the role of the CCR9/CCL25 axis on macrophage recruitment and fibrosis formation in a murine NASH model, providing new insights into therapeutic strategies for NASH.

LAY SUMMARY

Herein, we show that a specific chemokine axis involving a receptor (CCR9) and its ligand (CCL25) contributes to the progression of non-alcoholic steatohepatitis and carcinogenesis in humans and mice. Furthermore, treatment with a CCR9 antagonist ameliorates the development of steatohepatitis and holds promise for the treatment of patients with non-alcoholic steatohepatitis.

Differential TM4SF5-mediated SIRT1 modulation and metabolic signaling in nonalcoholic steatohepatitis progression

Nonalcoholic fatty liver disease is a chronic condition involving steatosis, steatohepatitis and fibrosis, and its progression remains unclear. Although the tetraspanin transmembrane 4 L six family member 5 (TM4SF5) is involved in hepatic fibrosis and cancer, its role in nonalcoholic steatohepatitis (NASH) progression is unknown. We investigated the contribution of TM4SF5 to liver pathology using transgenic and KO mice, diet- or drug-treated mice, in vitro primary cells, and in human tissue. TM4SF5-overexpressing mice exhibited nonalcoholic steatosis and NASH in an age-dependent manner. Initially, TM4SF5-positive hepatocytes and liver tissue exhibited lipid accumulation, decreased Sirtuin 1 (SIRT1), increased sterol regulatory-element binding proteins (SREBPs) and inactive STAT3 via suppressor of cytokine signaling (SOCS)1/3 upregulation. In older mice, TM4SF5 promoted inflammatory factor induction, SIRT1 expression and STAT3 activity, but did not change SOCS or SREBP levels, leading to active STAT3-mediated ECM production for NASH progression. A TM4SF5-associated increase in chemokines promoted SIRT1 expression and progression to NASH with fibrosis. Suppression of the chemokine CCL20 reduced immune cell infiltration and ECM production. Liver tissue from high-fat diet- or CCl4 -treated mice and human patients exhibited TM4SF5-dependent steatotic or steatohepatitic livers with links between TM4SF5-mediated SIRT1 modulation and SREBP or SOCS/STAT3 signaling axes. TM4SF5-mediated STAT3 activation in fibrotic NASH livers increased collagen I and laminin γ2. Both collagen I α1 and laminin γ2 suppression resulted in reduced SIRT1 and active STAT3, but no change in SREBP1 or SOCS, and abolished CCl4 -mediated mouse liver damage. TM4SF5-mediated signaling pathways that involve SIRT1, SREBPs and SOCS/STAT3 promoted progression to NASH. Therefore, TM4SF5 and its downstream effectors may be promising therapeutic targets to treat nonalcoholic fatty liver disease. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Translational insight into prothrombotic state and hypercoagulation in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an emerging and threatening pathological condition, ranging from fatty liver (FL) to chronic steatohepatitis (NASH), liver cirrhosis, and eventually to hepatocellular carcinoma (HCC). Recent findings suggest that patients with NAFLD have a higher risk of cardiovascular events and thromboembolism and that this risk is independent of metabolic diseases that are frequently associated with NAFLD, such as diabetes, hyperlipidaemia, and obesity. The vascular involvement of NAFLD might be considered its systemic burden, conditioning higher mortality in patients affected by the disease. These clinical findings suggested the existence of a prothrombotic state in NAFLD, which is partially unexplored and whose underlying mechanisms are to date not completely understood. Here, we review the mechanisms involved in the pathogenesis of the prothrombotic state in NAFLD across the progression from the healthy liver through the different stages of the disease. We focused on the possible role of several metabolic features of NAFLD possibly leading to hypercoagulation other than endothelial and platelet activation, such as insulin-resistance, nitric oxide production regulation, and gut microbiota homeostasis. Also, we analysed the involvement of plasminogen activator inhibitor-1 (PAI-1) and thromboinflammation taking place in NAFLD. Finally, we described factors striking a prothrombotic imbalance in NASH cirrhosis, with a particular focus on the pathogenesis of portal vein thrombosis.

Understanding lipotoxicity in NAFLD pathogenesis: is CD36 a key driver?

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. NAFLD stages range from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) which can progress to cirrhosis and hepatocellular carcinoma. One of the crucial events clearly involved in NAFLD progression is the lipotoxicity resulting from an excessive fatty acid (FFA) influx to hepatocytes. Hepatic lipotoxicity occurs when the capacity of the hepatocyte to manage and export FFAs as triglycerides (TGs) is overwhelmed. This review provides succinct insights into the molecular mechanisms responsible for lipotoxicity in NAFLD, including ER and oxidative stress, autophagy, lipoapotosis and inflammation. In addition, we highlight the role of CD36/FAT fatty acid translocase in NAFLD pathogenesis. Up-to-date, it is well known that CD36 increases FFA uptake and, in the liver, it drives hepatosteatosis onset and might contribute to its progression to NASH. Clinical studies have reinforced the significance of CD36 by showing increased content in the liver of NAFLD patients. Interestingly, circulating levels of a soluble form of CD36 (sCD36) are abnormally elevated in NAFLD patients and positively correlate with the histological grade of hepatic steatosis. In fact, the induction of CD36 translocation to the plasma membrane of the hepatocytes may be a determining factor in the physiopathology of hepatic steatosis in NAFLD patients. Given all these data, targeting the fatty acid translocase CD36 or some of its functional regulators may be a promising therapeutic approach for the prevention and treatment of NAFLD.

Effects of tesamorelin on hepatic transcriptomic signatures in HIV-associated NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity among people living with HIV that has a more aggressive course than NAFLD among the general population. In a recent randomized placebo-controlled trial, we demonstrated that the growth hormone-releasing hormone analog tesamorelin reduced liver fat and prevented fibrosis progression in HIV-associated NAFLD over 1 year. As such, tesamorelin is the first strategy that has shown to be effective against NAFLD among the population with HIV. The current study leveraged paired liver biopsy specimens from this trial to identify hepatic gene pathways that are differentially modulated by tesamorelin versus placebo. Using gene set enrichment analysis, we found that tesamorelin increased hepatic expression of hallmark gene sets involved in oxidative phosphorylation and decreased hepatic expression of gene sets contributing to inflammation, tissue repair, and cell division. Tesamorelin also reciprocally up- and downregulated curated gene sets associated with favorable and poor hepatocellular carcinoma prognosis, respectively. Notably, among tesamorelin-treated participants, these changes in hepatic expression correlated with improved fibrosis-related gene score. Our findings inform our knowledge of the biology of pulsatile growth hormone action and provide a mechanistic basis for the observed clinical effects of tesamorelin on the liver.

Activin A induces tumorigenesis of leiomyoma via regulation of p38β MAPK-mediated signal cascade

OBJECTIVE

The objective of this study was to investigate the role of p38-C/EBPβ signaling in leiomyoma cells and myometrial cells challenged with Activin A, and to identify specifically the isoform of p38 MAPK that mediates the effects of Activin A.

METHODS

The immortalization human leiomyoma cells (HuLM) and human myometrial cells (HM), and mouse myometrial tissues were treated with Activin A (4 nM) in response to p38α/β inhibition (10 μM SB202190) or depletion (p38 α/β-targeting siRNA or p38β muscle specific-knock out mice). p38 MAPK signaling molecules (p-p38 and p-C/EBPβ) and ECM components (COL1A1 and/or FN) were analyzed by Western blotting.

RESULTS

Activin A induced ECM accumulation in leiomyoma cells and myofibroblastic transformation in myometrical cells specifically by p38β MAPK.

CONCLUSION

This study is the first to demonstrate that activation of C/EBPβ by p38β MAPK may contribute to tumorigenesis and progression of Activin A-induced leiomyoma. Specific p38β inhibition may represent a novel and promising intervention for leiomyoma.

Cystathionine gamma-lyase/H2S system suppresses hepatic acetyl-CoA accumulation and nonalcoholic fatty liver disease in mice

AIMS

Hydrogen sulfide (H₂S) as a novel gasotransmitter can be endogenously produced in liver by cystathionine gamma-lyase (CSE). The dysfunctions of CSE/H₂S system have been linked to various liver diseases. Acetyl-CoA is the key intermediate from the metabolism of lipid. This study examined the roles of H₂S in hepatic acetyl-CoA and lipid metabolism.

MATERIALS AND METHODS

Both in vitro cell model and in vivo animal model of lipid accumulation were used in this study. Western blotting and real-time PCR were used for analysis of protein and mRNA expression. Acetyl-CoA was analyzed by a coupled enzyme assay, and lipid accumulation was observed with Oil Red O staining.

KEY FINDINGS

Incubation of human liver carcinoma (HepG2) cells with a mixture of free fatty acids (FFAs) or high glucose reduced CSE expression and H₂S production, promoted intracellular accumulation of acetyl-CoA and lipid. Supply of exogenous NaHS or cysteine reduced acetyl-CoA contents and lipid accumulation, while blockage of CSE activity promoted intracellular lipid accumulation. Furthermore, H₂S blocked FFAs-induced transcriptions of de novo lipogenesis, inflammation, and fibrosis-related genes. In vivo, knockout of CSE gene stimulated more hepatic acetyl-CoA and lipid accumulation in mice induced by high-fat choline-deficient diet. The expressions of lipogenesis, inflammation, and fibrosis-related genes were significantly higher in liver tissues from CSE knockout mice when compared with wild-type mice.

SIGNIFICANCE

CSE/H₂S system is indispensable for maintaining the homeostasis of acetyl-CoA and lipid accumulation and protecting from the development of inflammation and fibrosis in liver under excessive caloric ingestion.

Inhibition of suppressor of cytokine signaling 1 mediates the profibrotic effect of TWEAK/Fn14 signaling on kidney cells

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) engagement with the receptor Fn14 contributes to the fibrotic process of kidney cells in systemic lupus erythematosus. Downregulation of the protein suppressor of cytokine signaling 1 (SOCS1) correlates with amplified production of proinflammatory factors and cell apoptosis, which participate in the pathogenesis of lupus nephritis. To elucidate the potential role of SOCS1 in TWEAK/Fn14 signaling, we determined the SOCS1 levels in primary kidney cells from MRL/MpJ (control strain) or MRL/lpr (lupus-prone) mice. These cells (mesangial cells, glomerular endothelial cells, and tubular epithelial cells) were also evaluated after stimulation with TWEAK (0 to 250 ng/mL). The results showed that the lupus-prone cells exhibited reduced SOCS1 expression. TWEAK induced the production of profibrotic factors (laminin, fibronectin, (CC motif) ligand 20, etc.) in kidney cells from both mouse strains. TWEAK stimulation also decreased both the mRNA and protein levels of SOCS1 in all cells. Moreover, the effect of TWEAK on mesangial cells was amplified by pre-transfection of SOCS1 siRNA but was partly reduced with SOCS1 overexpression by adenoviral delivery. Therefore, TWEAK/Fn14 activation contributes to renal fibrosis in lupus nephritis involving the depression of SOCS1 function.

IRF-1 promotes renal fibrosis by downregulation of Klotho

Although the key role of renal fibrosis in the progression of chronic kidney disease (CKD) is well known, the causes of renal fibrosis are not fully clarified. In this study, interferon regulatory factor 1 (IRF-1), a mammalian transcription factor, was highly expressed in fibrotic kidney of CKD patients. Concordantly, the expression level of IRF-1 was significantly elevated in the kidney of unilateral ureteral obstruction (UUO) and Adriamycin nephropathy (ADR) mice. In tubular epithelial cells, overexpression of IRF-1 could induce profibrotic markers expression, which accompanied by dramatic downregulation of Klotho, an important inhibitor of renal fibrosis. Luciferase reporter analysis and ChIP assay revealed that IRF-1 repressed Klotho expression by downregulation of C/EBP-β, which regulates Klotho gene transcription via directly binding to its promoter. Further investigation showed that tumor necrosis factor-alpha may be an important inducement for the increase of IRF-1 in tubular epithelial cells after UUO and genetic deletion of IRF-1 attenuated renal fibrosis in UUO mice. Hence, these findings demonstrate that IRF-1 contributes to the pathogenesis of renal fibrosis by downregulation of Klotho, and suppresses IRF-1 may be a potential therapeutic target for CKD.

A blocking monoclonal antibody to CCL24 alleviates liver fibrosis and inflammation in experimental models of liver damage

Background & Aims

C-C motif chemokine ligand 24 (CCL24) is a chemokine that regulates inflammatory and fibrotic activities through its receptor, C-C motif chemokine receptor (CCR3). The aim of the study was to evaluate the involvement of the CCL24-CCR3 axis in liver fibrosis and inflammation and to assess the potential of its blockade, by a monoclonal anti-CCL24 antibody, as a therapeutic strategy for non-alcoholic steatohepatitis (NASH) and liver fibrosis.

Methods

Expression of CCL24 and CCR3 was evaluated in liver biopsies and blood samples. CCL24 involvement in NAFLD/NASH pathogenesis was assessed in Ccl24 knockout mouse using the methionine-choline deficient (MCD) diet experimental model. Antifibrotic and anti-inflammatory effects of CM-101 were tested in the MCD and STAM mouse models and in the thioacetamide (TAA) model in rats. Liver enzymes, liver morphology, histology and collagen deposition, as well as fibrosis- and inflammation-related protein expression were assessed. Activation of hepatic stellate cells (HSCs) was evaluated in the human LX2 cell line.

Results

Patients with NASH and advanced NAFLD exhibited significant expression of both CCL24 and CCR3 in liver and blood samples. In the experimental MCD-diet model, Ccl24 knockout mice showed an attenuated liver damage response compared to wild-type mice, exhibiting reduced histological NAFLD activity scores and fibrosis, as well as lower levels of liver enzymes. Blocking CCL24 using CM-101 robustly reduced liver damage in 3 experimental animal models (MCD, STAM and TAA), as demonstrated by attenuation of liver fibrosis and NAFLD activity score. Furthermore, blocking CCL24 by CM-101 significantly inhibited CCL24-induced HSC motility, α-SMA expression and pro-collagen I secretion.

Conclusion

Our results reveal that blocking CCL24 significantly attenuates liver fibrosis and inflammation and may have a potential therapeutic effect in patients with NASH and/or liver fibrosis.

Lay summary

CCL24 is a chemokine that regulates inflammation and fibrosis. It was found to be significantly expressed in patients with non-alcoholic steatohepatitis, in whom it regulates profibrotic processes in the liver. Herein, we show that blockade of CCL24 using a monoclonal antibody robustly attenuated liver fibrosis and inflammation in animal models, thus suggesting a potential therapeutic role for an anti-CCL24 agent.

•

CCL24 is a chemokine that regulates inflammatory and fibrotic activities through its receptor, CCR3.

•

Significant expression of CCL24 and CCR3 were found in liver biopsies and blood samples from patients with NAFLD/NASH.

•

CM-101, a monoclonal antibody that selectively targets CCL24, significantly attenuates fibrotic and inflammatory processes.

•

Blocking CCL24 may have a potential therapeutic effect in NASH and liver fibrosis.

Cerium oxide nanoparticles display antilipogenic effect in rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, ranging from steatosis to non-alcoholic steatohepatitis (NASH). Recently, cerium oxide nanoparticles (CeO₂NPs) have emerged as a new antioxidant agent with hepatoprotective properties in experimental liver disease. The aim of the current investigation was to elucidate whether CeO₂NPs display beneficial effects in an experimental model of NAFLD.Therefore, fifteen Wistar rats were subjected to a methionine and choline deficient diet (MCDD) for 6 weeks and intravenously treated with CeO₂NP or vehicle during the weeks three and four of the diet. The effect of CeO₂NPs on serum biochemistry, hepatic steatosis, inflammation, fatty acid content and expression of reactive oxygen species (ROS) and lipid metabolism related genes was assessed. MCDD fed rats showed increased inflammation, enhanced hepatic lipid accumulation of both saturated and unsaturated fatty acids (FAs) and overexpression of genes related to fatty liver and ROS metabolism. Treatment with CeO₂NPs was able to reduce the size and content of hepatocyte lipid droplets, the hepatic concentration of triglyceride- and cholesterol ester-derived FAs and the expression of several genes involved in cytokine, adipokine and chemokine signaling pathways. These findings suggest that CeO₂NPs could be of beneficial value in NAFLD.

CCL5 deficiency promotes liver repair by improving inflammation resolution and liver regeneration through M2 macrophage polarization

Despite the diverse etiologies of drug-induced liver injury (DILI), innate immunity activation is a common feature involved in DILI progression. However, the involvement of innate immunity regulation in inflammation resolution and liver regeneration in DILI remains obscure. Herein, we identified the chemokine CCL5 as a central mediator of innate immunity regulation in the pathogenesis of DILI. First, we showed that serum and hepatic CCL5 levels are elevated in both DILI patients and an APAP-induced liver injury (AILI) mouse model. Interestingly, both nonparenchymal cells and stressed hepatocytes are cell sources of CCL5 induction in response to liver injury. Functional experiments showed that CCL5 deficiency has no effect on the early phase of AILI but promotes liver repair in the late phase mainly by promoting inflammation resolution and liver regeneration, which are associated with an increased number of hepatic M2 macrophages. Mechanistically, CCL5 can directly activate M1 polarization and impede M2 polarization through the CCR1- and CCR5-mediated activation of the MAPK and NF-κB pathways. We then showed that CCL5 inhibition mediated by either a CCL5-neutralizing antibody or the antagonist Met-CCL5 can greatly alleviate liver injury and improve survival in an AILI mouse model. Our data demonstrate CCL5 induction during DILI, identify CCL5 as a novel innate immunity regulator in macrophage polarization, and suggest that CCL5 blockage is a promising therapeutic strategy for the treatment of DILI.

Noninvasive diagnostic criteria for nonalcoholic steatohepatitis based on gene expression levels in peripheral blood mononuclear cells

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) consists of nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH); the latter progresses to liver cirrhosis and hepatocellular carcinoma. Discriminating NASH from NAFL typically involves liver biopsy. The mechanism of NASH progression is unclear but may involve immunological pathways. In this study, we examined expression levels of cytokine- and chemokine-encoding genes in peripheral blood mononuclear cells (PBMCs) from NAFLD patients and established immunological criteria for discriminating NASH from NAFL.

METHODS

PBMCs were obtained from 54 patients diagnosed histologically with NAFLD (NAFL, 18; NASH, 36). mRNA was extracted from PBMCs, and expression levels of cytokine- and chemokine-encoding genes were determined by quantitative real-time PCR. Statistical analysis was performed by nonparametric test.

RESULTS

Expression levels of interferon (IFN)γ, interleukin (IL)2, IL15, C-C-motif chemokine ligand (CCL)2, IL10, and C-X-C-motif chemokine ligand (CXCL)11 were significantly upregulated in NASH patients compared with NAFL patients. Moreover, their expression levels were positively correlated with the degree of ballooning of hepatocytes but not of steatosis or lobular inflammation. We focused on those encoding IL10, IFNγ, and CCL2, and developed a scoring system to discriminate NASH from NAFL. The discriminatory power of the criteria was validated in an independent cohort.

CONCLUSIONS

Expression levels of the cytokine- and chemokine-encoding genes in PBMCs were positively correlated with ballooning, suggesting their utility for the diagnosis of NASH. The data indicate that peripheral as well as intrahepatic immunity is involved in the progression of NASH. Our findings afford new insight into immunological mechanisms of NASH and will facilitate its noninvasive diagnosis.

Potential circulating biomarkers of circulating chemokines CCL5, MIP-1β and HA as for early detection of cirrhosis related to chronic HBV (hepatitis B virus) infection

BACKGROUND

Due to no clinical symptoms in the compensated stage of cirrhosis, it is usually diagnosed when decompensated complications occur. In this study, the noninvasive circulating biomarkers for early detection to compensated stage of cirrhosis in patients with chronic HBV (hepatitis B virus) infection was explored.

METHODS

According to the Guideline of Prevention and Treatment of Chronic Hepatitis B (2015 Update), 78 patients with CHB (chronic hepatitis B) were divided into mild group, moderate-to-advanced group, while 73 patients with HBV-related cirrhosis were divided into compensated group and decompensated group. Nineteen cytokines and chemokines, four serum liver fibrosis markers were measured using chemiluminescence. The expression of CCL5 in liver tissue was determined with immunohistochemistry.

RESULTS

The CCL5 expression level in serum increased in CHB patients with aggravated liver injury and significantly decreased in cirrhosis patients with advanced liver fibrosis. ROC analysis revealed that the serum levels of CCL5, HA and MIP-1β were effective in distinguishing patients with cirrhosis from patients with CHB, especially for CCL5. Increasing serum level of CCL5 in CHB patients was severely associated with disease progression.

CONCLUSIONS

The serum levels of CCL5, HA and MIP-1β maybe used to distinguish cirrhosis from CHB patients, moreover, CCL5 was the most reliable marker. The increasing serum levels of CCL5 were significantly related to disease progression in CHB patients.

Impaired Skeletal Muscle Regeneration Induced by Macrophage Depletion Could Be Partly Ameliorated by MGF Injection

Skeletal muscle injury is one of the most common injuries in sports medicine. Our previous study found that macrophage depletion impairs muscle regeneration and that mechano growth factor (MGF) may play an important role in this process. However, whether injection of MGF protects against impaired muscle regeneration after macrophage depletion has not been explored. Therefore, we generated a muscle contusion and macrophage depletion mouse model and injected MGF into the damaged muscle. Comprehensive morphological and genetic analyses were performed on the injured skeletal muscle after macrophage depletion and MGF injection. The results showed that injection of MGF did not exert a protective effect on muscle fiber regeneration; however, it did decrease fibrosis in the contused skeletal muscle after macrophage depletion. Moreover, MGF injection decreased the expression of muscle inflammatory cytokines (TNF-α, IFN-γ, IL-1β, and TGF-β), chemokines (CCL2, CCL5, and CXCR4), oxidative stress factors (gp91phox) and matrix metalloproteinases (MMP-1, MMP-2, MMP-9, MMP-10, and MMP-14). These results suggest that the impairment of skeletal muscle regeneration induced by macrophage depletion could be partly ameliorated by MGF injection and that inflammatory cytokines, oxidative stress factors, chemokines, and MMP may be involved in this process.

Possible association of arrestin domain-containing protein 3 and progression of non-alcoholic fatty liver disease

The prevalence of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) is increasing worldwide. Several effective drugs for these diseases are now in development and under clinical trials. It is important to reveal the mechanism of the development of NAFLD and NASH. We investigated the role of arrestin domain-containing protein 3 (ARRDC3), which is linked to obesity in men and regulates body mass, adiposity and energy expenditure, in the progression of NAFLD and NASH. We performed knockdown of endogenous ARRDC3 in human hepatocytes and examined the inflammasome-associated gene expression by real-time PCR-based array. We also examined the effect of conditioned medium from endogenous ARRDC3-knockdown-hepatocytes on the apoptosis of hepatic stellate cells. We observed that free acids enhanced the expression of ARRDC3 in hepatocytes. Knockdown of ARRDC3 could lead to the inhibition of inflammasome-associated gene expression in hepatocytes. We also observed that conditioned medium from endogenous ARRDC3-knockdown-hepatocytes enhances the apoptosis of hepatic stellate cells. ARRDC3 has a role in the progression of NAFLD and NASH and is one of the targets for the development of the effective treatment of NAFLD and NASH.

Hepatocellular Carcinoma Is Associated With Gut Microbiota Profile and Inflammation in Nonalcoholic Fatty Liver Disease

The gut-liver axis plays a pivotal role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), which is the third leading cause of hepatocellular carcinoma (HCC) worldwide. However, the link between gut microbiota and hepatocarcinogenesis remains to be clarified. The aim of this study was to explore what features of the gut microbiota are associated with HCC in patients with cirrhosis and NAFLD. A consecutive series of patients with NAFLD-related cirrhosis and HCC (group 1, 21 patients), NAFLD-related cirrhosis without HCC (group 2, 20 patients), and healthy controls (group 3, 20 patients) was studied for gut microbiota profile, intestinal permeability, inflammatory status, and circulating mononuclear cells. We finally constructed a model depicting the most relevant correlations among these features, possibly involved in hepatocarcinogenesis. Patients with HCC showed increased levels of fecal calprotectin, while intestinal permeability was similar to patients with cirrhosis but without HCC. Plasma levels of interleukin 8 (IL8), IL13, chemokine (C-C motif) ligand (CCL) 3, CCL4, and CCL5 were higher in the HCC group and associated with an activated status of circulating monocytes. The fecal microbiota of the whole group of patients with cirrhosis showed higher abundance of Enterobacteriaceae and Streptococcus and a reduction in Akkermansia. Bacteroides and Ruminococcaceae were increased in the HCC group, while Bifidobacterium was reduced. Akkermansia and Bifidobacterium were inversely correlated with calprotectin concentration, which in turn was associated with humoral and cellular inflammatory markers. A similar behavior was also observed for Bacteroides. Conclusion: Our results suggest that in patients with cirrhosis and NAFLD the gut microbiota profile and systemic inflammation are significantly correlated and can concur in the process of hepatocarcinogenesis.

Non-parenchymal hepatic cell lipotoxicity and the coordinated progression of non-alcoholic fatty liver disease and atherosclerosis

PURPOSE OF REVIEW

Non-alcoholic fatty liver disease (NAFLD) appears to be independently associated with the development of atherosclerosis. The biological mechanisms underlying this association are complex, and likely involve liver-resident cell types other than hepatocytes. Thus, we review recent evidence that non-parenchymal hepatic cell responses to lipid excess contribute to the pathogenesis of both NAFLD and atherosclerosis.

RECENT FINDINGS

Significant independent associations between NAFLD and atherosclerosis have been identified through cross-sectional studies and meta-analyses. Mechanistic studies in cell cultures and in rodent models suggest that liver-resident macrophages, activated hepatic stellate cells (HSC) and liver sinusoidal endothelial cells (LSEC) mount lipotoxic responses under NAFLD conditions which can contribute to the progression of both NAFLD and atherosclerosis.

SUMMARY

Non-parenchymal hepatic cell types exhibit some similarity in their responses to lipid excess, and in their pathogenic mechanisms, which likely contribute to the coordinated progression of NAFLD and atherosclerosis. In response to lipotoxic conditions, macrophages, Kupffer cells and HSC initiate robust inflammatory responses, whereas LSEC generate excess reactive oxygen species (ROS). The extent to which inflammatory cytokines and ROS produced by non-parenchymal cells contribute to the progression of both NAFLD and atherosclerosis warrants further investigation.

Maraviroc improves hepatic triglyceride content but not inflammation in a murine nonalcoholic fatty liver disease model induced by a chronic exposure to high-fat diet

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the general population. Its severity ranges from simple steatosis to cirrhosis. C-C chemokine ligand type 5 or RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted) plays an important role in the progression of hepatic inflammation and fibrosis. Our objective was to examine the preventive and therapeutic effects of maraviroc (MVC), a C-C chemokine receptor 5 antagonist, on liver pathology in an NAFLD mouse model. A total of 60 male C57BL/6 mice were randomly assigned to 1 of 4 groups: (1) high-fat diet (HFD) group or control group, (2) preventive group (HFD group plus MVC in drinking water since the beginning of the study), (3) early-therapeutic group (HFD group plus MVC in drinking starting at week 24 of the study), and (4) late-therapeutic group (HFD group plus MVC in drinking water starting at week 36 of the study). All mice were sacrificed at week 48. The hepatic triglyceride concentration in the HFD group was significantly higher than that in the groups treated with MVC at any time. Gene expression associated with lipogenesis (diacylglycerol acyltransferase 2 and proliferator-activated receptor-γ), insulin resistance (insulin receptor substrate-2), and β-oxidation (carnitine palmitoyltransferase 1A and acyl-CoA oxidase) was significantly reduced in all the groups treated with MVC. In summary, the beneficial effect of MVC on hepatic steatosis is maintained throughout the study.

Pathophysiological characteristics of non-alcoholic steatohepatitis-like changes in cholesterol-loaded type 2 diabetic rats

Spontaneously Diabetic Torii (SDT) fatty rats, a new obese diabetic model, reportedly presented with features of non-alcoholic steatohepatitis (NASH) after 32 weeks of age. We tried to accelerate the onset of NASH in SDT fatty rats using dietary cholesterol loading and noticed changes in the blood choline level which is expected to be a NASH biomarker. Body weight and biochemical parameters were measured from 8 to 24 weeks of age. At 16, 20, 24 weeks, pathophysiological analysis of the livers were performed. Hepatic lipids, lipid peroxides, and the expression of mRNA related to triglyceride (TG) synthesis, inflammation, and fibrosis were evaluated at 24 weeks. Hepatic fibrosis was observed in SDT fatty rats fed cholesterol-enriched diets (SDT fatty-Cho) from 16 weeks. Furthermore, hepatic lipids and lipid peroxide were significantly higher in SDT fatty-Cho than SDT fatty rats fed normal diets at 24 weeks. Hepatic mRNA expression related to TG secretion decreased in SDT fatty-Cho, and the mRNA expression related to inflammation and fibrosis increased in SDT fatty-Cho at 24 weeks. Furthermore, SDT fatty-Cho presented with increased plasma choline, similar to human NASH. There were no significant changes in the effects of feeding a cholesterol-enriched diet in Sprague-Dawley rats. SDT fatty-Cho has the potential to become a valuable animal model for NASH associated with type 2 diabetes and obesity.

Cenicriviroc for the treatment of non-alcoholic steatohepatitis and liver fibrosis

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) has an increasing prevalence worldwide. At present, no specific pharmacotherapy is approved for NAFLD. Simple steatosis and nonalcoholic steatohepatitis (NASH) can progress to liver fibrosis that is associated with mortality in NAFLD. The recruitment of inflammatory monocytes and macrophages via chemokine receptor CCR2 as well as of lymphocytes and hepatic stellate cells via CCR5 promote the progression of NASH to fibrosis. Areas covered: I summarize preclinical and clinical data on the efficacy and safety of the dual CCR2/CCR5 inhibitor cenicriviroc (CVC, also TBR-652 or TAK-652) for the treatment of NASH and fibrosis. In animal models of liver diseases, CVC potently inhibits macrophage accumulation in the liver and ameliorates fibrosis. In a phase 2b clinical trial (CENTAUR) on 289 patients with NASH and fibrosis, CVC consistently demonstrated liver fibrosis improvement after 1 year of therapy and had an excellent safety profile, leading to the implementation of a phase 3 trial (AURORA). Expert opinion: Preclinical and clinical data support the development of CVC as a safe and potent antifibrotic agent. However, open questions around CVC are the durability of antifibrotic responses, divergent effects on NASH versus fibrosis, potential long-term concerns and the expected path to approval.

Neutralization of IL-15 abrogates experimental immune-mediated cholangitis in diet-induced obese mice

Obesity is a global epidemic affecting chronic inflammatory diseases. Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that can occur as an extraintestinal manifestation of inflammatory bowel disease (IBD). Previously we reported that patients with PSC who are obese have a higher risk of advanced liver disease. Currently it is unknown how obesity accelerates or worsens PSC. We evaluated the progression of PSC in an antigen-driven cholangitis mouse model of diet-induced obesity. Obesity was induced in our murine model of immune-mediated cholangitis (OVAbil). OVAbil mice were fed standard chow or high-fat/sucrose diet for twelve weeks followed by induction of biliary inflammation by OVA-specific T cell transfer. Histopathological damage in portal tracts was scored and serum collected. Neutralizing antibodies against IL-15 were administered daily until study termination. Obese mice developed exacerbated liver inflammation and damage. Immune cell phenotyping in liver revealed greater numbers of neutrophils and CD8+ T cells in obese mice. Higher levels of cytokines and chemokines were found in obese mice with cholangitis. Immuno-neutralizing antibodies against IL-15 greatly attenuated cholangitis in obese mice. Obesity exacerbated experimental PSC in part by overproduction of IL-15. Timely targeting of IL-15 may slow the progression of PSC.