Blockade of interleukin-6 signaling enhances hepatic steatosis but improves liver injury in methionine choline-deficient diet-fed mice

Maternal Supplementation of Dietary Choline and DHA During Gestational Nutrition Restriction Alters Hepatic mRNA and miRNA Expression Patterns in Full-Term Fetal Pigs

BACKGROUND

Supplementing choline and DHA to pregnant gilts modified fetal pig hepatic global DNA methylation induced by gestational malnutrition, suggesting that gene expression and regulation and its associated metabolic pathways are affected in the liver of offspring during growth and development.

OBJECTIVES

This study aimed to investigate the effect of maternal supplementation of choline, DHA, and their interaction on hepatic mRNA expression, miRNA regulation, and metabolic pathways in the fetal pigs born to malnourished mothers.

METHODS

The abundance of mRNA and miRNA was profiled in fetal liver from sows with undernutrition supplemented with choline and DHA in a 2 × 2 factorial design. The effects of choline, DHA, and their interaction on mRNA and miRNA expression were evaluated. Identification of the Biological Processes from the Gene Ontology database and miRNA Target Prediction Analysis were performed using the DAVID Functional Annotation Tool and Ingenuity Pathway Analysis. The identified miRNA-mRNA pairings were validated using RT-qPCR.

RESULTS

In total, 144 mRNA and 1 miRNA were altered by supplementation of choline, and the alterations were associated with the inhibitions of cardiac hypertrophy signaling, IL-6 signaling, IL-3 signaling, the Th1 pathway, and the acute phase response signaling pathway. Further, 151 mRNAs and 6 miRNAs were altered by maternal supplementation DHA and were associated with inhibition of 5 inositol-related pathways, 5 immune-related pathways, and 7 other pathways and the stimulation of peroxisome proliferator-activated receptor signaling and RhoGDI signaling pathways. In addition, 383 mRNAs and 25 miRNAs displayed choline × DHA interactions including synergistic effects on acute phase response signaling, and antagonistic effects on tRNA splicing, peroxisome proliferator-activated receptor α/retinoid X receptor α activation, and sirtuin signaling, NAD signaling, and RNA polymerase I transcription pathways. Ten of the identified 20 miRNA-mRNA pairings were validated using RT-qPCR.

CONCLUSIONS

The supplementation of choline, DHA, or choline plus DHA to pregnant gilts modifies liver mRNA, miRNA, and pathways in fetal pigs during gestational undernutrition.

Fluoxetine promotes IL-10-dependent metabolic defenses to protect from sepsis-induced lethality

Selective serotonin reuptake inhibitors (SSRIs) are some of the most prescribed drugs in the world. While they are used for their ability to increase serotonergic signaling in the brain, SSRIs are also known to have a broad range of effects beyond the brain, including immune and metabolic effects. Recent studies have demonstrated that SSRIs are protective in animal models and humans against several infections, including sepsis and COVID-19; however, the mechanisms underlying this protection are largely unknown. Here, we mechanistically link two previously described effects of the SSRI fluoxetine in mediating protection against sepsis. We show that fluoxetine-mediated protection is independent of peripheral serotonin and instead increases levels of circulating interleukin-10 (IL-10). IL-10 is necessary for protection from sepsis-induced hypertriglyceridemia, preventing cardiac effects including impairment of glucose oxidation, ectopic lipid accumulation, ventricular stretch and possibly cardiac failure. Our work reveals a beneficial "off-target" effect of fluoxetine, and reveals a protective immunometabolic defense mechanism with therapeutic potential.

S-Adenosylmethionine: A Multifaceted Regulator in Cancer Pathogenesis and Therapy

S-adenosylmethionine (SAMe) is a key methyl donor that plays a critical role in a variety of cellular processes, such as DNA, RNA and protein methylation, essential for maintaining genomic stability, regulating gene expression and maintaining cellular homeostasis. The involvement of SAMe in cancer pathogenesis is multifaceted, as through its multiple cellular functions, it can influence tumor initiation, progression and therapeutic resistance. In addition, the connection of SAMe with polyamine synthesis and oxidative stress management further underscores its importance in cancer biology. Recent studies have highlighted the potential of SAMe as a biomarker for cancer diagnosis and prognosis. Furthermore, the therapeutic implications of SAMe are promising, with evidence suggesting that SAMe supplementation or modulation could improve the efficacy of existing cancer treatments by restoring proper methylation patterns and mitigating oxidative damage and protect against damage induced by chemotherapeutic drugs. Moreover, targeting methionine cycle enzymes to both regulate SAMe availability and SAMe-independent regulatory effects, particularly in methionine-dependent cancers such as colorectal and lung cancer, presents a promising therapeutic approach. Additionally, exploring epitranscriptomic regulations, such as m6A modifications, and their interaction with non-coding RNAs could enhance our understanding of tumor progression and resistance mechanisms. Precision medicine approaches integrating patient subtyping and combination therapies with chemotherapeutics, such as decitabine or doxorubicin, together with SAMe, can enhance chemosensitivity and modulate epigenomics, showing promising results that may improve treatment outcomes. This review comprehensively examines the various roles of SAMe in cancer pathogenesis, its potential as a diagnostic and prognostic marker, and its emerging therapeutic applications. While SAMe modulation holds significant promise, challenges such as bioavailability, patient stratification and context-dependent effects must be addressed before clinical implementation. In addition, better validation of the obtained results into specific cancer animal models would also help to bridge the gap between research and clinical practice.

Decoding Health: Exploring Essential Biomarkers Linked to Metabolic Dysfunction-Associated Steatohepatitis and Type 2 Diabetes Mellitus

The investigation of biomarkers for metabolic diseases such as type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated steatohepatitis (MASH) reveals their potential for advancing disease treatment and addressing their notable overlap. The connection between MASH, obesity, and T2DM highlights the need for an integrative management approach addressing mechanisms like insulin resistance and chronic inflammation. Obesity contributes significantly to the development of MASH through lipid dysregulation, insulin resistance, and chronic inflammation. Selective biomarker targeting offers a valuable strategy for detecting these comorbidities. Biomarkers such as CRP, IL-6, and TNF-α serve as indicators of inflammation, while HOMA-IR, fasting insulin, and HbA1c are essential for evaluating insulin resistance. Additionally, triglycerides, LDL, and HDL are crucial for comprehending lipid dysregulation. Despite the growing importance of digital biomarkers, challenges in research methodologies and sample variability persist, necessitating further studies to validate diagnostic tools and improve health interventions. Future opportunities include developing non-invasive biomarker panels, using multiomics, and using machine learning to enhance prognoses for diagnostic accuracy and therapeutic outcomes.

IL-6 and diabetic kidney disease

Diabetic kidney disease (DKD) is a severe microvascular complication of diabetes associated with high mortality and disability rates. Inflammation has emerged as a key pathological mechanism in DKD, prompting interest in novel therapeutic approaches targeting inflammatory pathways. Interleukin-6 (IL-6), a well-established inflammatory cytokine known for mediating various inflammatory responses, has attracted great attention in the DKD field. Although multiple in vivo and in vitro studies highlight the potential of targeting IL-6 in DKD treatment, its exact roles in the disease remains unclear. This review presents the roles of IL-6 in the pathogenesis of DKD, including immunoinflammation, metabolism, hemodynamics, and ferroptosis. In addition, we summarize the current status of IL-6 inhibitors in DKD-related clinical trials and discuss the potential of targeting IL-6 for treating DKD in the clinic.

Modulation of SIRT6 related signaling pathways of p-AKT/mTOR and NRF2/HO-1 by memantine contributes to curbing the progression of tamoxifen/HFD-induced MASH in rats

Metabolic dysfunction-associated steatohepatitis (MASH) is a chronic liver disorder marked by hepatic fat accumulation and inflammatory infiltrates which may evolve to cirrhosis. Clinical studies have demonstrated the higher risk of MASH development after tamoxifen (TAM) therapy, especially in obese patients. Therefore, we aimed to evaluate MASH induction by TAM combined with high fat diet (HFD) and the potential interference of memantine (MEMA) with MASH progression via modulation of SIRT6 and its related signaling pathways. MASH was induced in female Wistar rats by co-administration of TAM (25 mg/kg/day, p.o.) and HFD for 5 weeks. Liver function biomarkers, tissue triglyceride and cholesterol, MASH scoring, SIRT6 with its related signals, and lipid synthesis/oxidation markers were estimated. By comparison to MASH group, MEMA improved liver function indices (ALT, AST, ALP, albumin) and reduced the progression of MASH, evidenced by decreased accumulation of lipids in hepatic tissue, improved histological features, and reduced MASH scoring. MEMA enhanced hepatic SIRT6 and downregulated p-AKT/mTOR signaling, that subsequently reduced expressions of the lipid synthesis biomarkers (SREBP1c, SCD), while elevating the lipid oxidation markers (PPAR-α, CPT1). Moreover, MEMA enhanced NRF2/HO-1 signaling, with subsequently improved antioxidant defense and pro-inflammatory/anti-inflammatory cytokines balance. Analysis of SIRT6 correlations with p-AKT/mTOR, NRF2/HO-1, SREBP1c, and PPAR-α further confirmed our results. Consequently, we conclude that MEMA could interfere with MASH progression, at least in part, via enhanced SIRT6 expression and modulation of its related p-AKT/mTOR and NRF2/HO-1 signaling pathways, eventually reducing liver steatosis and inflammation. That could be a promising therapeutic modality for curbing MASH progression.

Evaluating the antifibrotic potential of naringenin, asiatic acid, and icariin using murine and human precision-cut liver slices

Liver fibrosis is an exaggerated wound healing response defined by the excessive accumulation of extracellular matrix. This study investigated the antifibrotic potential of naringenin (NRG), asiatic acid (AA), and icariin (ICA) using murine and human precision-cut liver slices (PCLS). These natural products have shown promise in animal models, but human data are lacking. In this study, PCLS prepared from male mouse liver tissue (mPCLS), healthy human liver tissue (hhPCLS), and cirrhotic human liver tissue (chPCLS) were cultured for 48 h with varying concentrations of the three compounds. Our findings indicate that NRG reduced collagen type 1 (COL1A1) expression in a concentration-dependent manner in both mPCLS and chPCLS, decreased fibrosis-related gene expression, and significantly lowered pro-collagen type 1 (PCOL1A1) levels in the culture medium by 54 ± 21% (mPCLS) and 78 ± 35% (chPCLS). Furthermore, NRG effectively inhibited IL-1β and TNF-α in mPCLS and IL-1β in chPCLS on both gene and protein levels. AA specifically reduced COL1A1 and PCOL1A1 in chPCLS, while ICA selectively downregulated Col1a1 and Acta2 gene expression in mPCLS. This study suggests NRG's potential as an effective antifibrotic agent, warranting further investigation into its mechanisms and therapeutic applications in liver fibrosis.

Hepatocyte-specific loss of DDB1 attenuates hepatic steatosis but aggravates liver inflammation and fibrosis in MASH

BACKGROUND

MASH is a common clinical disease that can lead to advanced liver conditions, but no approved pharmacotherapies are available due to an incomplete understanding of its pathogenesis. Damaged DNA binding protein 1 (DDB1) participates in lipid metabolism. Nevertheless, the function of DDB1 in MASH is unclear.

METHODS

Clinical liver samples were obtained from patients with MASH and control individuals by liver biopsy. Hepatocyte-specific Ddb1-knockout mice and liver Hmgb1 knockdown mice were fed with a methionine-and choline-deficient diet to induce MASH.

RESULTS

We found that the expression of DDB1 in the liver was significantly decreased in MASH models. Hepatocyte-specific ablation of DDB1 markedly alleviated methionine-and choline-deficient diet-induced liver steatosis but unexpectedly exacerbated inflammation and fibrosis. Mechanistically, DDB1 deficiency attenuated hepatic steatosis by downregulating the expression of lipid synthesis and uptake genes. We identified high-mobility group box 1 as a key candidate target for DDB1-mediated liver injury. DDB1 deficiency upregulated the expression and extracellular release of high-mobility group box 1, which further increased macrophage infiltration and activated HSCs, ultimately leading to the exacerbation of liver inflammation and fibrosis.

CONCLUSIONS

These data demonstrate the independent regulation of hepatic steatosis and injury in MASH. These findings have considerable clinical implications for the development of therapeutic strategies for MASH.

Role of pattern recognition receptors in the development of MASLD and potential therapeutic applications

Metabolic dysfunction-associated steatotic liver disease (MASLD) has become one of the most prevalent liver diseases worldwide, and its occurrence is strongly associated with obesity, insulin resistance (IR), genetics, and metabolic stress. Ranging from simple fatty liver to metabolic dysfunction-associated steatohepatitis (MASH), even to severe complications such as liver fibrosis and advanced cirrhosis or hepatocellular carcinoma, the underlying mechanisms of MASLD progression are complex and involve multiple cellular mediators and related signaling pathways. Pattern recognition receptors (PRRs) from the innate immune system, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), NOD-like receptors (NLRs), RIG-like receptors (RLRs), and DNA receptors, have been demonstrated to potentially contribute to the pathogenesis for MASLD. Their signaling pathways can induce inflammation, mediate oxidative stress, and affect the gut microbiota balance, ultimately resulting in hepatic steatosis, inflammatory injury and fibrosis. Here we review the available literature regarding the involvement of PRR-associated signals in the pathogenic and clinical features of MASLD, in vitro and in animal models of MASLD. We also discuss the emerging targets from PRRs for drug developments that involved agent therapies intended to arrest or reverse disease progression, thus enabling the refinement of therapeutic targets that can accelerate drug development.

Essential phospholipids impact cytokine secretion and alter lipid-metabolizing enzymes in human hepatocyte cell lines

BACKGROUND

Essential phospholipids (EPL) are hepatoprotective.

METHODS

The effects on interleukin (IL)-6 and -8 secretion and on certain lipid-metabolizing enzymes of non-cytotoxic concentrations of EPL (0.1 and 0.25 mg/ml), polyenylphosphatidylcholine (PPC), and phosphatidylinositol (PtdIns) (both at 0.1 and 1 mg/ml), compared with untreated controls, were assessed in human hepatocyte cell lines (HepG2, HepaRG, and steatotic HepaRG).

RESULTS

Lipopolysaccharide (LPS)-induced IL-6 secretion was significantly decreased in HepaRG cells by most phospholipids, and significantly increased in steatotic HepaRG cells with at least one concentration of EPL and PtdIns. LPS-induced IL-8 secretion was significantly increased in HepaRG and steatotic HepaRG cells with all phospholipids. All phospholipids significantly decreased amounts of fatty acid synthase in steatotic HepaRG cells and the amounts of acyl-CoA oxidase in HepaRG cells. Amounts of lecithin cholesterol acyltransferase were significantly decreased in HepG2 and HepaRG cells by most phospholipids, and significantly increased with 0.1 mg/ml PPC (HepaRG cells) and 1 mg/ml PtdIns (steatotic HepaRG cells). Glucose-6-phosphate dehydrogenase activity was unaffected by any phospholipid in any cell line.

CONCLUSIONS

EPL, PPC, and PtdIns impacted the secretion of pro-inflammatory cytokines and affected amounts of several key lipid-metabolizing enzymes in human hepatocyte cell lines. Such changes may help liver function improvement, and provide further insights into the EPL's mechanism of action.

Blood cell parameters and risk of nonalcoholic fatty liver disease: a comprehensive Mendelian randomization study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is on the rise globally, and past research suggests a significant association with various blood cell components. Our goal is to explore the potential correlation between whole blood cell indices and NAFLD risk using Mendelian randomization (MR).

METHODS

We analyzed data from 4,198 participants in the 2017-2018 National Health and Nutrition Examination Survey to investigate the link between blood cell indicators and NAFLD. Using various methods like weighted quantile sum and multivariate logistic regression, we assessed the association. Additionally, two-sample Mendelian randomization were employed to infer causality for 36 blood cell indicators and NAFLD.

RESULTS

Multivariate logistic regression identified 10 NAFLD risk factors. Weighted quantile sum revealed a positive correlation (p = 6.03e-07) between total blood cell indices and NAFLD, with hemoglobin and lymphocyte counts as key contributors. Restricted cubic spline analysis found five indicators with significant nonlinear correlations to NAFLD. Mendelian randomization showed a notable association between reticulocyte counts and NAFLD using the inverse-variance weighted method.

CONCLUSIONS

Hematological markers pose an independent NAFLD risk, with a positive causal link found for reticulocyte count. These results emphasize the importance of monitoring NAFLD and investigating specific underlying mechanisms further.

Boron Facilitates Amelioration of Hepatic Injury by the Osmolyte Glycine and Resolves Injury by Improving the Tissue Redox Homeostasis

Background: Glycine is a conditional non-essential amino acid in human and other mammals. It is abundant in the liver and is known for a wide spectrum of characteristics including the antioxidant, antiinflammatory, immunomodulatory, and cryoprotective effects. The amino acid is a naturally occurring osmolyte compatible with protein surface interactions and has been reported in literature as a potent therapeutic immuno-nutrient for liver diseases such as alcoholic liver disease. Oral glycine administration protects ethanol-induced liver injury, improves serum and tissue lipid profile, and alleviates hepatic injury in various conditions. In recent years, sodium salt of boron (borax) has been reported for its beneficial effects on cellular stress, including the effects on cell survival, immunity, and tissue redox state. Incidentally both glycine and boron prevent apoptosis and promote cell survival under stress. Objective: This study investigates the beneficial effect of borax on liver protection by glycine. Methods: Briefly, liver toxicity was induced in rats by a single intraperitoneal injection of thioacetamide (400 mg/kg b. wt.). Results: Significant changes in oxidative stress and liver function test parameters, the molybdenum Fe-S flavin hydroxylase activity, nitric oxide and tissue histopathology were observed in thioacetamide treated positive control group. The changes were ameliorated both by glycine as well as borax, but the combinatorial treatment yielded a better response indicating the impact of boron supplementation on glycine mediated protection of liver injury in experimental animal model. Conclusions: The study has clinical implications as the hepatotoxicity caused by thioacetamide mimics features of hepatitis C infection in human.

Interleukins: Pathogenesis in Non-Alcoholic Fatty Liver Disease

Inflammatory cytokines have been implicated as crucial contributors to the onset and progression of non-alcoholic fatty liver disease (NAFLD). The exact mechanisms by which interleukins (ILs) contribute to NAFLD may vary, and ongoing research is aimed at understanding the specific roles of different ILs in the pathogenesis of this condition. In addition, variations in environmental factors and genetics in each individual can influence the onset and/or progression of NAFLD. The lack of clinical studies related to the potential therapeutic properties of IL-1 inhibitors currently does not allow us to conclude their validity as a therapeutic option, although preclinical studies show promising results. Further studies are needed to elucidate their beneficial properties in NAFLD treatment.

Linking fatty liver diseases to hepatocellular carcinoma by hepatic stellate cells

Hepatic stellate cells (HSCs), a distinct category of non-parenchymal cells in the liver, are critical for liver homeostasis. In healthy livers, HSCs remain non-proliferative and quiescent. However, under conditions of acute or chronic liver damage, HSCs are activated and participate in the progression and regulation of liver diseases such as liver fibrosis, cirrhosis, and liver cancer. Fatty liver diseases (FLD), including nonalcoholic (NAFLD) and alcohol-related (ALD), are common chronic inflammatory conditions of the liver. These diseases, often resulting from multiple metabolic disorders, can progress through a sequence of inflammation, fibrosis, and ultimately, cancer. In this review, we focused on the activation and regulatory mechanism of HSCs in the context of FLD. We summarized the molecular pathways of activated HSCs (aHSCs) in mediating FLD and their role in promoting liver tumor development from the perspectives of cell proliferation, invasion, metastasis, angiogenesis, immunosuppression, and chemo-resistance. We aimed to offer an in-depth discussion on the reciprocal regulatory interactions between FLD and HSC activation, providing new insights for researchers in this field.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

MSC-sEV Treatment Polarizes Pro-Fibrotic M2 Macrophages without Exacerbating Liver Fibrosis in NASH

Mesenchymal stem/stromal cell small extracellular vesicles (MSC-sEVs) have shown promise in treating a wide range of animal models of various human diseases, which has led to their consideration for clinical translation. However, the possibility of contraindication for MSC-sEV use is an important consideration. One concern is that MSC-sEVs have been shown to induce M2 macrophage polarization, which is known to be pro-fibrotic, potentially indicating contraindication in fibrotic diseases such as liver fibrosis. Despite this concern, previous studies have shown that MSC-sEVs alleviate high-fat diet (HFD)-induced non-alcoholic steatohepatitis (NASH). To assess whether the pro-fibrotic M2 macrophage polarization induced by MSC-sEVs could worsen liver fibrosis, we first verified that our MSC-sEV preparations could promote M2 polarization in vitro prior to their administration in a mouse model of NASH. Our results showed that treatment with MSC-sEVs reduced or had comparable NAFLD Activity Scores and liver fibrosis compared to vehicle- and Telmisartan-treated animals, respectively. Although CD163⁺ M2 macrophages were increased in the liver, and serum IL-6 levels were reduced in MSC-sEV treated animals, our data suggests that MSC-sEV treatment was efficacious in reducing liver fibrosis in a mouse model of NASH despite an increase in pro-fibrotic M2 macrophage polarization.

Plasma Cytokeratin-18 Fragment Level Reflects the Metabolic Phenotype in Obesity

There is growing interest in the non-invasive identification and monitoring of the outcome of liver damage in obese patients. Plasma cytokeratin-18 (CK-18) fragment levels correlate with the magnitude of hepatocyte apoptosis and have recently been proposed to independently predict the presence of non-alcoholic steatohepatitis (NASH). The aim of the study was to analyze the associations of CK-18 with obesity and related complications: insulin resistance, impaired lipid metabolism and the secretion of hepatokines, adipokines and pro-inflammatory cytokines. The study involved 151 overweight and obese patients (BMI 25-40), without diabetes, dyslipidemia or apparent liver disease. Liver function was assessed based on alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and the fatty liver index (FLI). CK-18 M30 plasma levels, FGF-21, FGF-19 and cytokines were determined by ELISA. CK-18 values >150 U/l were accompanied by high ALT, GGT and FLI, insulin resistance, postprandial hypertriglyceridemia, elevated FGF-21 and MCP-1 and decreased adiponectin. ALT activity was the strongest independent factor influencing high CK-18 plasma levels, even after an adjustment for age, sex and BMI [β coefficient (95%CI): 0.40 (0.19-0.61)]. In conclusion, the applied CK-18 cut-off point at 150 U/l allows to distinguish between two metabolic phenotypes in obesity.

IL-6-GP130 signaling protects human hepatocytes against lipid droplet accumulation in humanized liver models

Liver steatosis is an increasing health issue with few therapeutic options, partly because of a paucity of experimental models. In humanized liver rodent models, abnormal lipid accumulation in transplanted human hepatocytes occurs spontaneously. Here, we demonstrate that this abnormality is associated with compromised interleukin-6 (IL-6)-glycoprotein 130 (GP130) signaling in human hepatocytes because of incompatibility between host rodent IL-6 and human IL-6 receptor (IL-6R) on donor hepatocytes. Restoration of hepatic IL-6-GP130 signaling, through ectopic expression of rodent IL-6R, constitutive activation of GP130 in human hepatocytes, or humanization of an Il6 allele in recipient mice, substantially reduced hepatosteatosis. Notably, providing human Kupffer cells via hematopoietic stem cell engraftment in humanized liver mice also corrected the abnormality. Our observations suggest an important role of IL-6-GP130 pathway in regulating lipid accumulation in hepatocytes and not only provide a method to improve humanized liver models but also suggest therapeutic potential for manipulating GP130 signaling in human liver steatosis.

Clonal haematopoiesis and risk of chronic liver disease

Chronic liver disease is a major public health burden worldwide1. Although different aetiologies and mechanisms of liver injury exist, progression of chronic liver disease follows a common pathway of liver inflammation, injury and fibrosis2. Here we examined the association between clonal haematopoiesis of indeterminate potential (CHIP) and chronic liver disease in 214,563 individuals from 4 independent cohorts with whole-exome sequencing data (Framingham Heart Study, Atherosclerosis Risk in Communities Study, UK Biobank and Mass General Brigham Biobank). CHIP was associated with an increased risk of prevalent and incident chronic liver disease (odds ratio = 2.01, 95% confidence interval (95% CI) [1.46, 2.79]; P < 0.001). Individuals with CHIP were more likely to demonstrate liver inflammation and fibrosis detectable by magnetic resonance imaging compared to those without CHIP (odds ratio = 1.74, 95% CI [1.16, 2.60]; P = 0.007). To assess potential causality, Mendelian randomization analyses showed that genetic predisposition to CHIP was associated with a greater risk of chronic liver disease (odds ratio = 2.37, 95% CI [1.57, 3.6]; P < 0.001). In a dietary model of non-alcoholic steatohepatitis, mice transplanted with Tet2-deficient haematopoietic cells demonstrated more severe liver inflammation and fibrosis. These effects were mediated by the NLRP3 inflammasome and increased levels of expression of downstream inflammatory cytokines in Tet2-deficient macrophages. In summary, clonal haematopoiesis is associated with an elevated risk of liver inflammation and chronic liver disease progression through an aberrant inflammatory response.

Myokines: Crosstalk and Consequences on Liver Physiopathology

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease mainly characterized by the hepatic accumulation of lipid inducing a deregulation of β-oxidation. Its advanced form is non-alcoholic steatohepatitis (NASH), which, in addition to lipid accumulation, induces hepatocellular damage, oxidative stress and fibrosis that can progress to cirrhosis and to its final stage: hepatocellular carcinoma (HCC). To date, no specific therapeutic treatment exists. The implications of organ crosstalk have been highlighted in many metabolic disorders, such as diabetes, metabolic-associated liver diseases and obesity. Skeletal muscle, in addition to its role as a reservoir and consumer of energy and carbohydrate metabolism, is involved in this inter-organs’ communication through different secreted products: myokines, exosomes and enzymes, for example. Interestingly, resistance exercise has been shown to have a beneficial impact on different metabolic pathways, such as lipid oxidation in different organs through their secreted products. In this review, we will mainly focus on myokines and their effects on non-alcoholic fatty liver disease, and their complication: non-alcoholic steatohepatitis and HCC.

Overview of Cellular and Soluble Mediators in Systemic Inflammation Associated with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease in Western countries, affecting approximately 25% of the adult population. This condition encompasses a spectrum of liver diseases characterized by abnormal accumulation of fat in liver tissue (non-alcoholic fatty liver, NAFL) that can progress to non-alcoholic steatohepatitis (NASH), characterized by the presence of liver inflammation and damage. The latter form often coexists with liver fibrosis which, in turn, may progress to a state of cirrhosis and, potentially, hepatocarcinoma, both irreversible processes that often lead to the patient's death and/or the need for liver transplantation. Along with the high associated economic burden, the high mortality rate among NAFLD patients raises interest, not only in the search for novel therapeutic approaches, but also in early diagnosis and prevention to reduce the incidence of NAFLD-related complications. In this line, an exhaustive characterization of the immune status of patients with NAFLD is mandatory. Herein, we attempted to gather and compare the current and relevant scientific evidence on this matter, mainly on human reports. We addressed the current knowledge related to circulating cellular and soluble mediators, particularly platelets, different leukocyte subsets and relevant inflammatory soluble mediators.

SOCS2 protects against chemical-induced hepatocellular carcinoma progression by modulating inflammation and cell proliferation in the liver

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancers worldwide, but the precise intracellular mechanisms underlying the progression of this inflammation associated cancer are not well established. SOCS2 protein plays an important role in the carcinogenesis of different tumors by regulating cytokine signalling through the JAK/STAT axis. However, its role in HCC is unclear. Here, we investigate the role of SOCS2 in HCC progression and its potential as HCC biomarker. The effects of SOCS2 in HCC progression were evaluated in an experimental model of diethylnitrosamine (DEN)-induced HCC in C57BL/6 and SOCS2 deficient mice, in cultured hepatic cells, and in liver samples from HCC patients. Mice lacking SOCS2 showed higher liver tumor burden with increased malignancy grade, inflammation, fibrosis, and proliferation than their controls. Protein and gene expression analysis reported higher pSTAT5 and pSTAT3 activation, upregulation of different proteins involved in survival and proliferation, and increased levels of proinflammatory and pro-tumoral mediators in the absence of SOCS2. Clinically relevant, downregulated expression of SOCS2 was found in neoplasia from HCC patients compared to healthy liver tissue, correlating with the malignancy grade. In summary, our data show that lack of SOCS2 increases susceptibility to chemical-induced HCC and suggest the tumor suppressor role of this protein by regulating the oncogenic and inflammatory responses mediated by STAT5 and STAT3 in the liver. Hence, SOCS2 emerges as an attractive target molecule and potential biomarker to deepen in the study of HCC treatment.

The immunological role of ADAMs in the field of gastroenterological chronic inflammatory diseases and cancers: a review

Metalloproteinases cleave transmembrane proteins that play critical roles in inflammation and cancers. Metalloproteinases include a disintegrin and metalloprotease (ADAM), which we previously examined using a fluorescence assay system, and described their association with resistance to systemic therapy in cancer patients. There are also many reports on the relation between ADAM expression and the prognosis of patients with gastroenterological chronic inflammatory diseases and cancers. Inhibiting their immunomodulating activity in chronic inflammation restores innate immunity and potentially prevents the development of various cancers. Among the numerous critical immune system-related molecules, we focus on major histocompatibility complex class I polypeptide-related sequence A (MICA), MICB, intracellular adhesion molecule (ICAM)-1, TNF-α, IL-6 receptor (IL-6R), and Notch. This review summarizes our current understanding of the role of ADAMs in gastroenterological diseases with regard to the immune system. Several Food and Drug Administration (FDA)-approved inhibitors of ADAMs have been identified, and potential therapies for targeting ADAMs in the treatment of chronic inflammatory diseases and cancers are discussed. Some ongoing clinical trials for cancers targeting ADAMs are also introduced.

Inhibition of the JAK2/STAT3 pathway and cell cycle re-entry contribute to the protective effect of remote ischemic pre-conditioning of rat hindlimbs on cerebral ischemia/reperfusion injury

AIMS

Remote ischemic pre-conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC.

METHODS

A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p-JAK2-, p-STAT3-, cyclin D1-, and cyclin-dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining.

RESULTS

RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p-JAK2 and p-STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO-induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p-STAT3 in the ischemic brain.

CONCLUSION

RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re-entry by RIPC is associated with downregulation of STAT3 phosphorylation.

Dietary camellia seed oil attenuates liver injury in mice chronically exposed to alcohol

Dietary fat composition is closely associated with the pathological development of alcoholic liver disease (ALD). Fat enriched with saturated fatty acids protects whereas with polyunsaturated fatty acids aggravates alcohol-induced liver injury. However, limited study has addressed how monounsaturated fatty acids (MUFAs) determines the pathological process of ALD. Our study was conducted to evaluate the effect of MUFAs-enriched-camellia seed oil (CSO) on alcohol-induced liver injury. The ALD model was established by feeding C57BL/6 mice with Lieber-DeCarli diet, and with either CSO or polyunsaturated fatty acids (PUFAs)-enriched-corn oil (CO) as fat source. After 4-week-intervention, CSO-feed rescued alcohol-induced liver injury compared to CO-feed, evidenced by measurements of plasma ALT activity, H&E stain, and hepatic cleaved-Caspase-3 expression. Besides, CSO-feed alleviated alcohol-induced oxidative stress, associated with NRF2 and Hif-1α expressions improvement. The reduction of F4/80 immunostaining and the decreased expressions of hepatic TNF-α and IL-6 suggested CSO-feed improved alcohol-induced inflammation. The mechanistic analysis showed that the inhibition of ASK1 and MAPKs might contribute to CSO-protected liver injury. Notably, we observed CSO-feed relieved the gut microbiota disturbance with the decreased Firmicutes and Turicibater, and the increased Bacteroidota, Alloprevotella, and Bacteroides, and reduced circulatory endotoxin level and lipolysis of adipose tissue, which are the known pathogenic factors in alcohol-induced liver injury. Unexpectedly, CSO induced more hepatic steatosis than CO-feed. In conclusion, CSO attenuated chronic alcohol consumption-induced liver injury but enhanced hepatic steatosis. CSO could be a potential dietary choice for alcoholic individuals with liver injury.

Depletion of hepatic stellate cells inhibits hepatic steatosis in mice

BACKGROUND AND AIM

Hepatic stellate cells (HSCs), the main source of extracellular matrix in hepatic fibrogenesis, produce various cytokines, growth factors, and morphogenetic proteins. Among these, several factors are known to promote hepatocyte lipid accumulation, suggesting that HSCs can be efficient therapeutic targets for non-alcoholic steatohepatitis (NASH). This study aimed to investigate the effects of HSC depletion on the development of hepatic steatosis and fibrosis in a murine NASH model.

METHODS

C57BL/6 mice were treated with gliotoxin (GTX), an apoptosis inducer of activated HSCs under the feeding of a choline-deficient l-amino acid-defined high-fat diet for 4 weeks. For in vitro study, Hc3716 cells, immortalized human hepatocytes, were treated with fatty acids in the presence or absence of LX2, immortalized HSCs.

RESULTS

Choline-deficient l-amino acid-defined high-fat diet increased pronounced hepatic steatosis, which was attenuated by GTX treatment, together with a reduction in the number of activated HSCs. This change was associated with the downregulation of the peroxisome proliferator-activated receptor gamma (PPARγ) and its downstream genes, including adipocyte protein 2, cluster of differentiation 36 (CD36), and fatty acid transport protein 1, all of which increase the fatty acid uptake into hepatocytes. As expected, GTX treatment improved hepatic fibrosis. Co-culture of hepatocytes with HSCs enhanced intracellular lipid accumulation, together with the upregulation of PPARγ and CD36 protein expressions.

CONCLUSIONS

In addition to the improvement in hepatic fibrogenesis, depletion of HSCs had a favorable effect on hepatic lipid metabolism in a mouse NASH model, suggesting that HSCs are potentially efficient targets for the treatment of NASH.

Hepatic damage caused by long-term high cholesterol intake induces a dysfunctional restorative macrophage population in experimental NASH

Excessive dietary cholesterol is preferentially stored in the liver, favoring the development of nonalcoholic steatohepatitis (NASH), characterized by progressive hepatic inflammation and fibrosis. Emerging evidence indicates a critical contribution of hepatic macrophages to NASH severity. However, the impact of cholesterol on these cells in the setting of NASH remains elusive. Here, we demonstrate that the dietary cholesterol content directly affects hepatic macrophage global gene expression. Our findings suggest that the modifications triggered by prolonged high cholesterol intake induce long-lasting hepatic damage and support the expansion of a dysfunctional pro-fibrotic restorative macrophage population even after cholesterol reduction. The present work expands the understanding of the modulatory effects of cholesterol on innate immune cell transcriptome and may help identify novel therapeutic targets for NASH intervention.

Contribution of organokines in the development of NAFLD/NASH associated hepatocellular carcinoma

Globally the incidence of hepatocellular carcinoma (HCC) is on an upsurge. Evidence is accumulating that liver disorders like nonalcoholic fatty liver disease (NAFLD) and its more progressive form nonalcoholic steatohepatitis (NASH) are associated with increased risk of developing HCC. NAFLD has a prevalence of about 25% and 50%-90% in obese population. With the growing burden of obesity epidemic worldwide, HCC presents a major healthcare burden. While cirrhosis is one of the major risk factors of HCC, available literature suggests that NAFLD/NASH associated HCC also develops in minimum or noncirrhotic livers. Therefore, there is an urgent need to understand the pathogenesis and risk factors associated with NAFLD and NASH related HCC that would help in early diagnosis and favorable prognosis of HCC secondary to NAFLD. Adipokines, hepatokines and myokines are factors secreted by adipocytes, hepatocytes and myocytes, respectively, playing essential roles in cellular homeostasis, energy balance and metabolism with autocrine, paracrine and endocrine effects. In this review, we endeavor to focus on the role of these organokines in the pathogenesis of NAFLD/NASH and its progression to HCC to augment the understanding of the factors stimulating hepatocytes to acquire a malignant phenotype. This shall aid in the development of novel therapeutic strategies and tools for early diagnosis of NAFLD/NASH and HCC.

Celecoxib attenuates hepatosteatosis by impairing de novo lipogenesis via Akt-dependent lipogenic pathway

Mounting evidence indicates that hepatic de novo lipogenesis is a common abnormality in non-alcoholic fatty liver disease (NAFLD) patients. We investigated whether a selective COX-2 inhibitor, celecoxib, alleviates hepatic steatosis by targeting an Akt-driven lipogenic pathway. We estimated the efficacy of celecoxib in a novel Akt-driven NAFLD mouse model established via hydrodynamic transfection of activated forms of AKT and in fructose-fed NAFLD mice that exhibited increased insulin-independent hepatic lipogenesis. AKT-transfected and insulin-stimulated human hepatoma cells were used for the in vitro experiments. Haematoxylin and eosin staining, immunohistochemistry and immunoblotting were performed for mechanistic studies. The results revealed that celecoxib ameliorated hepatic steatosis in the AKT-triggered NAFLD mice. Mechanistically, celecoxib effectively suppressed AKT/mTORC1 signalling and its downstream lipogenic cascade in the Akt-driven NAFLD mice and in vitro. Furthermore, celecoxib had limited efficacy in alleviating hepatic lipid accumulation and showed no influence on lipogenic proteins associated with hepatic lipogenesis in fructose-administered mice. This study suggests that celecoxib may be favourable for the treatment of NAFLD, especially in the subset with Akt-triggered hepatic lipogenesis.

Angiotensin Converting Enzyme-2 Therapy Improves Liver Fibrosis and Glycemic Control in Diabetic Mice With Fatty Liver

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is frequently associated with type 2 diabetes. However, there is no specific medical therapy to treat this condition. Angiotensin-converting enzyme 2 (ACE2) of the protective renin angiotensin system generates the antifibrotic peptide angiotensin-(1-7) from profibrotic angiotensin II peptide. In this study, we investigated the therapeutic potential of ACE2 in diabetic NAFLD mice fed a high-fat (20%), high-cholesterol (2%) diet for 40 weeks. Mice were given a single intraperitoneal injection of ACE2 using an adeno-associated viral vector at 30 weeks of high-fat, high-cholesterol diet (15 weeks after induction of diabetes) and sacrificed 10 weeks later. ACE2 significantly reduced liver injury and fibrosis in diabetic NAFLD mice compared with the control vector injected mice. This was accompanied by reductions in proinflammatory cytokine expressions, hepatic stellate cell activation, and collagen 1 expression. Moreover, ACE2 therapy significantly increased islet numbers, leading to an increased insulin protein content in β-cells and plasma insulin levels with subsequent reduction in plasma glucose levels compared with controls. Conclusion: We conclude that ACE2 gene therapy reduces liver fibrosis and hyperglycemia in diabetic NAFLD mice and has potential as a therapy for patients with NAFLD with diabetes.

High-Throughput Sequencing Reveals CXCR4 and IGF1 Behave Different Roles in Weightlessness Osteoporosis

Objective

This study is aimed at screening the differential expression profiles of mRNA under weightlessness osteoporosis through high-throughput sequencing technology, as well as investigating the pathogenesis of weightlessness osteoporosis at the molecular level especially in bone marrow mesenchymal stem cells (BMSCs).

Methods

The mouse bone marrow mesenchymal stem cell line was divided into ground group and simulated microgravity (SMG) group. BMP-2 was used to induce osteogenic differentiation, and SMG group was placed into 2D-gyroscope to simulate weightless condition. Transcriptome sequencing was performed by Illumina technology, DEGs between ground and SMG group was conducted using the DEseq2 algorithm. Molecular functions and signaling pathways enriched by DEGs were then comprehensively analyzed via multiple bioinformatic approaches including but not limited to GO, KEGG, GSEA, and PPI analysis.

Results

A total of 263 DEGs were identified by comparing these 2 groups, including 186 upregulated genes and 77 downregulated genes. GO analysis showed that DEGs were enriched in osteoblasts, osteoclasts cell proliferation, differentiation, and apoptosis; KEGG analysis revealed that DEGs were significantly enriched in the TNF signaling pathway and FoxO signaling pathway; the enrichment results from Reactome database displayed that DEGs were mainly involved in the transcription of Hoxb3 gene, RUNX1 recruitment KMT2A gene, and activation of Hoxa2 chromatin signaling pathway. The four genes, IL6, CXCR4, IGF1, and PLOD2, were identified as hub genes for subsequent analysis.

Conclusions

This study elucidated the significance of 10 hub genes in the development of weightlessness osteoporosis. In addition, the results of this study provide a theoretical basis and novel ideas for the subsequent research of the pathogenesis and clinical treatment of weightlessness osteoporosis.

Interleukin 6 in diabetes, chronic kidney disease and cardiovascular disease: mechanisms and therapeutic perspectives

INTRODUCTION

Diabetes, chronic kidney disease (CKD) and cardiovascular disease (CVD) are cardiometabolic diseases that remain amongst the leading causes of morbidity and premature mortality. Here, we review the current understanding of how anti-inflammatory intervention via inhibition of the pro-inflammatory but pleiotropic cytokine interleukin (IL) 6 may benefit patients with these or related diseases or complications.

AREAS COVERED

Based on a PubMed literature search, this review integrates and contextualizes evidence regarding the clinical utility of anti-IL-6 intervention in the treatment of cardiometabolic diseases, as well as of the associated condition non-alcoholic hepatosteatosis.

EXPERT OPINION

Evidence implicates the pro-inflammatory effects of IL-6 in the pathophysiology of diabetes, CKD and CVD. Thus, targeting the IL-6 pathway holds a therapeutic potential in these cardiometabolic disorders. However, because IL-6 has multiple homeostatic roles, antagonizing this cytokine may be associated with side effects such as increased risk of infection as seen with other anti-inflammatory drugs. Additional studies are required to establish the benefit-risk profile of anti-IL-6 intervention in the cardiometabolic diseases, whilst also considering alternative interventions such as lifestyle changes. IL-6 is also elevated in NASH, but the clinical usefulness of targeting IL-6 in this hepatic disorder remains largely unexplored.

Lactational High Fat Diet in Mice Causes Insulin Resistance and NAFLD in Male Offspring Which Is Partially Rescued by Maternal Metformin Treatment

Maternal metabolic disease and diet during pregnancy and lactation have important implications for the programming of offspring metabolic disease. In addition, high-fat diets during pregnancy and lactation can predispose the offspring to non-alcoholic fatty liver disease (NAFLD), a rising health threat in the U.S. We developed a model of maternal high-fat feeding exclusively during the lactation period. We previously showed that offspring from dams, given lactational high-fat diet (HFD), are predisposed to obesity, glucose intolerance, and inflammation. In separate experiments, we also showed that lactational metformin treatment can decrease offspring metabolic risk. The purpose of these studies was to understand the programming implications of lactational HFD on offspring metabolic liver disease risk. Dams were fed a 60% lard-based HFD from the day of delivery through the 21-day lactation period. A subset of dams was also given metformin as a co-treatment. Starting at weaning, the offspring were fed normal fat diet until 3 months of age; at which point, a subset was challenged with an additional HFD stressor. Lactational HFD led male offspring to develop hepatic insulin resistance. The post-weaning HFD challenge led male offspring to progress to NAFLD with more severe outcomes in the lactational HFD-challenged offspring. Co-administration of metformin to lactating dams on HFD partially rescued the offspring liver metabolic defects in males. Lactational HFD or post-weaning HFD had no impact on female offspring who maintained a normal insulin sensitivity and liver phenotype. These findings indicate that HFD, during the lactation period, programs the adult offspring to NAFLD risk in a sexually dimorphic manner. In addition, early life intervention with metformin via maternal exposure may prevent some of the liver programming caused by maternal HFD.

New insights into IL-6 family cytokines in metabolism, hepatology and gastroenterology

IL-6 family cytokines are defined by the common use of the signal-transducing receptor chain glycoprotein 130 (gp130). Increasing evidence indicates that these cytokines are essential in the regulation of metabolic homeostasis as well as in the pathophysiology of multiple gastrointestinal and liver disorders, thus making them attractive therapeutic targets. Over the past few years, therapies modulating gp130 signalling have grown exponentially in several clinical settings including obesity, cancer and inflammatory bowel disease. A newly engineered gp130 cytokine, IC7Fc, has shown promising preclinical results for the treatment of type 2 diabetes, obesity and liver steatosis. Moreover, drugs that modulate gp130 signalling have shown promise in refractory inflammatory bowel disease in clinical trials. A deeper understanding of the main roles of the IL-6 family of cytokines during homeostatic and pathological conditions, their signalling pathways, sources of production and target cells will be crucial to the development of improved treatments. Here, we review the current state of the role of these cytokines in hepatology and gastroenterology and discuss the progress achieved in translating therapeutics targeting gp130 signalling into clinical practice.

The Interplay between Insulin Resistance, Inflammation, Oxidative Stress, Base Excision Repair and Metabolic Syndrome in Nonalcoholic Fatty Liver Disease

One of the most common chronic liver disorders, affecting mainly people in Western countries, is nonalcoholic fatty liver disease (NAFLD). Unfortunately, its pathophysiological mechanism is not fully understood, and no dedicated treatment is available. Simple steatosis can lead to nonalcoholic steatohepatitis and even to fibrosis, cancer, and cirrhosis of the liver. NAFLD very often occurs in parallel with type 2 diabetes mellitus and in obese people. Furthermore, it is much more likely to develop in patients with metabolic syndrome (MS), whose criteria include abdominal obesity, elevated blood triacylglycerol level, reduced high-density lipoprotein cholesterol level, increased blood pressure, and high fasting glucose. An important phenomenon in MS is also insulin resistance (IR), which is very common in NAFLD. Liver IR and NAFLD development are linked through an interaction between the accumulation of free fatty acids, hepatic inflammation, and increased oxidative stress. The liver is particularly exposed to elevated levels of reactive oxygen species due to a large number of mitochondria in hepatocytes. In these organelles, the main DNA repair pathway is base excision repair (BER). The present article will illustrate how impairment of BER may be related to the development of NAFLD.

30-Day spexin treatment of mice with diet-induced obesity (DIO) and type 2 diabetes (T2DM) increases insulin sensitivity, improves liver functions and metabolic status

Spexin (SPX) is a 14 aa peptide discovered in 2007 using bioinformatics methods. SPX inhibits food intake and regulates lipid, and carbohydrate metabolism. Here, we evaluate the ability of SPX at improving metabolic control and liver function in obese and type 2 diabetic animals. The effects of 30 days SPX treatment of mice with experimentally induced obesity (DIO) or type 2 diabetes (T2DM) on serum glucose and lipid levels, insulin sensitivity and hormonal profile (insulin, glucagon, adiponectin, leptin, TNF alpha, IL-6 and IL-1β) are characterized. In addition, alterations of hepatic lipid and glycogen contents are evaluated. We report that SPX decreases body weight in healthy and DIO mice, and reduces lipid content in all three animal groups. SPX improves insulin sensitivity in DIO and T2DM animals. In addition, SPX modulates hormonal and metabolic profile by regulating the concentration of adiponectin (concentration increase) and leptin (concentration decrease) in the serum blood of DIO and T2DM mice. Lastly, SPX decreases lipid content as well as IL-6 and TNF-α protein levels in liver of DIO and T2DM mice, and reduces IL-6 and TNF-alpha concentrations in the serum derived from T2DM mice. Based on our results, we conclude that SPX could be involved in the development of obesity and type 2 diabetes mellitus and it can be further evaluated as a potential target for therapy of DIO and T2DM.

Liver macrophages and inflammation in physiology and physiopathology of non-alcoholic fatty liver disease

Non‐alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, being a common comorbidity of type 2 diabetes and with important links to inflammation and insulin resistance. NAFLD represents a spectrum of liver conditions ranging from steatosis in the form of ectopic lipid storage, to inflammation and fibrosis in nonalcoholic steatohepatitis (NASH). Macrophages that populate the liver play important roles in maintaining liver homeostasis under normal physiology and in promoting inflammation and mediating fibrosis in the progression of NAFLD toward to NASH. Liver macrophages are a heterogenous group of innate immune cells, originating from the yolk sac or from circulating monocytes, that are required to maintain immune tolerance while being exposed portal and pancreatic blood flow rich in nutrients and hormones. Yet, liver macrophages retain a limited capacity to raise the alarm in response to danger signals. We now know that macrophages in the liver play both inflammatory and noninflammatory roles throughout the progression of NAFLD. Macrophage responses are mediated first at the level of cell surface receptors that integrate environmental stimuli, signals are transduced through multiple levels of regulation in the cell, and specific transcriptional programmes dictate effector functions. These effector functions play paramount roles in determining the course of disease in NAFLD and even more so in the progression towards NASH. The current review covers recent reports in the physiological and pathophysiological roles of liver macrophages in NAFLD. We emphasise the responses of liver macrophages to insulin resistance and the transcriptional machinery that dictates liver macrophage function.

Chronic low-dose exposure to imidacloprid potentiates high fat diet-mediated liver steatosis in C57BL/6J male mice

Hepatic steatosis is known to precede a continuum of events that lead to hepatic metabolic dysfunction, inflammation and carcinogenesis. Recently, studies have linked xenobiotic exposures to hepatic steatogenesis and its associated metabolic disorders; however, the underlying mechanisms remain elusive. This study aimed to elucidate the mechanistic role of imidacloprid in the prevalence of high fat diet (HFD)-induced liver steatosis, using a C57BL/6J mice model. Mice (3 weeks old) were fed with HFD and treated with 0.6 mg/kg bw/day (one-tenth of the NOAEL) of imidacloprid through water or diet, for 24 weeks. In a controlled group, mice were fed with only HFD. At the end of the study, imidacloprid treatment significantly potentiated HFD-induced body weight gain in mice. Also, imidacloprid increased the liver weights of mice, with complimentary reductions in mesenteric and gonadal white adipose tissue weights. Histopathological analysis of liver revealed a drastic steatosis in imidacloprid treated mice. Following a real-time qPCR analysis, imidacloprid upregulated transcriptions of hepatic fatty acid biosynthesis-related transcription factors and genes. Imidacloprid also induced hepatic expression of the gene encoding pregnane X receptor; but had no significant effect on hepatic expressions of liver X receptor and aryl hydrocarbon receptor. The imidacloprid treatment further enhanced serum alanine aminotransferase levels but downregulated hepatic antioxidant mRNA expressions. Ultimately, this study suggested an imidacloprid-potentiation effects on prevalence of HFD-induced liver steatosis via transcriptional modulations of the hepatic FA biosynthesis pathway.

Hepatic steatosis and steatohepatitis: a functional meta-analysis of sex-based differences in transcriptomic studies

Background

Previous studies have described sex-based differences in the epidemiological and clinical patterns of non-alcoholic fatty liver disease (NAFLD); however, we understand relatively little regarding the underlying molecular mechanisms. Herein, we present the first systematic review and meta-analysis of NAFLD transcriptomic studies to identify sex-based differences in the molecular mechanisms involved during the steatosis (NAFL) and steatohepatitis (NASH) stages of the disease.

Methods

Transcriptomic studies in the Gene Expression Omnibus database were systematically reviewed following the PRISMA statement guidelines. For each study, NAFL and NASH in premenopausal women and men were compared using a dual strategy: gene-set analysis and pathway activity analysis. Finally, the functional results of all studies were integrated into a meta-analysis.

Results

We reviewed a total of 114 abstracts and analyzed seven studies that included 323 eligible patients. The meta-analyses identified significantly altered molecular mechanisms between premenopausal women and men, including the overrepresentation of genes associated with DNA regulation, vinculin binding, interleukin-2 responses, negative regulation of neuronal death, and the transport of ions and cations in premenopausal women. In men, we discovered the overrepresentation of genes associated with the negative regulation of interleukin-6 and the establishment of planar polarity involved in neural tube closure.

Conclusions

Our meta-analysis of transcriptomic data provides a powerful approach to identify sex-based differences in NAFLD. We detected differences in relevant biological functions and molecular terms between premenopausal women and men. Differences in immune responsiveness between men and premenopausal women with NAFLD suggest that women possess a more immune tolerant milieu, while men display an impaired liver regenerative response.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-021-00368-1.

Hepatocyte-specific IL11 cis-signaling drives lipotoxicity and underlies the transition from NAFLD to NASH

IL11 is important for fibrosis in non-alcoholic steatohepatitis (NASH) but its role beyond the stroma in liver disease is unclear. Here, we investigate the role of IL11 in hepatocyte lipotoxicity. Hepatocytes highly express IL11RA and secrete IL11 in response to lipid loading. Autocrine IL11 activity causes hepatocyte death through NOX4-derived ROS, activation of ERK, JNK and caspase-3, impaired mitochondrial function and reduced fatty acid oxidation. Paracrine IL11 activity stimulates hepatic stellate cells and causes fibrosis. In mouse models of NASH, hepatocyte-specific deletion of Il11ra1 protects against liver steatosis, fibrosis and inflammation while reducing serum glucose, cholesterol and triglyceride levels and limiting obesity. In mice deleted for Il11ra1, restoration of IL11 cis-signaling in hepatocytes reconstitutes steatosis and inflammation but not fibrosis. We found no evidence for the existence of IL6 or IL11 trans-signaling in hepatocytes or NASH. These data show that IL11 modulates hepatocyte metabolism and suggests a mechanism for NAFLD to NASH transition.

Modulation of hepatocyte sialylation drives spontaneous fatty liver disease and inflammation

Circulatory protein glycosylation is a biomarker of multiple disease and inflammatory states and has been applied in the clinic for liver dysfunction, heart disease and diabetes. With the notable exception of antibodies, the liver produces most of the circulatory glycoproteins, including the acute phase proteins released as a function of the inflammatory response. Among these proteins is β-galactoside α2,6-sialyltransferase (ST6Gal1), an enzyme required for α2,6-linked sialylation of glycoproteins. Here, we describe a hepatocyte-specific conditional knockout of ST6Gal1 (H-cKO) using albumin promoter-driven Cre-lox recombination. We confirm the loss of circulatory glycoprotein α2,6 sialylation and note no obvious dysfunction or pathology in young H-cKO mice, yet these mice show robust changes in plasma glycoprotein fucosylation, branching and the abundance of bisecting GlcNAc and marked changes in a number of metabolic pathways. As H-cKO mice aged, they spontaneously developed fatty liver disease characterized by the buildup of fat droplets in the liver, inflammatory cytokine production and a shift in liver leukocyte phenotype away from anti-inflammatory Kupffer cells and towards proinflammatory M1 macrophages. These findings connect hepatocyte and circulatory glycoprotein sialylation to the regulation of metabolism and inflammation, potentially identifying the glycome as a new target for liver-driven disease.

Dietary Rapeseed Oil Supplementation Reduces Hepatic Steatosis in Obese Men-A Randomized Controlled Trial

SCOPE

Effective treatment for obesity associated non-alcoholic fatty liver disease (NAFLD) is limited. Dietary supplementation of n-3 polyunsaturated fatty acids, specifically alpha linolenic acid (ALA), can resolve intrahepatic lipid content (IHL). This study investigates the effect of daily supplementation of either refined rapeseed (RA), containing high amounts of ALA, or refined olive (OL) oil on IHL and glucose metabolism in NAFLD patients.

METHODS AND RESULTS

27 obese men consumed an isocaloric diet including either 50 g of RA or OL daily for 8 weeks. Hepatic proton magnetic resonance spectroscopy, hyperinsulinemic-euglycemic clamp studies and blood tests are performed before and at the end of the study. At 8 weeks a significant reduction in IHL is observed for RA (13.1 ± 1.6 before versus 11.1 ± 1.6% after intervention) versus OL (13.3 ± 2.5 before versus 15.7 ± 2.7% after intervention). For RA, a 21% reduction (P < 0.02) in serum free fatty acids (FFA) and a 1.68-fold increase (P = 0.03) of serum interleukin-6 (IL-6) is observed after 8 weeks.

CONCLUSION

RA has a beneficial effect on hepatic lipid metabolism as shown by reduced IHL and serum FFA. RA induced IL-6 production seems to be liver protective confirming previous results.

Different roles of interleukin 6 and interleukin 11 in the liver: implications for therapy

The interleukin 6 (IL6) family of proteins regulate important cellular processes and act through a variety of signaling pathways via a shared gp130 receptor. In the liver, there is a large body of evidence showing a protective and pro-regenerative role for IL6 cis and trans signaling. While a few studies suggest a pathological role for IL6 trans-signaling in the liver. IL11 is often thought of as similar to IL6 and redundancy has been inferred. However, recent studies reveal that IL6R and IL11RA are expressed on dissimilar cell types and these cytokines actually have very different roles in biology and pathology. In the liver, IL6R is mostly expressed on immune cells, whereas IL11RA is highly expressed on hepatocytes and hepatic stellate cells, both of which exhibit autocrine IL11 activity. In contrast to the beneficial effects of IL6 in the liver, IL11 causes liver disease and its expression in stromal and parenchymal cells leads to fibrosis, inflammation, steatosis and hepatic failure. In this review, we address IL6 and IL11 in the context of liver function. We end by discussing the possibility of IL6 gain-of-function versus IL11 inhibition as therapeutic approaches to treat liver disease. 1,2.

Arachidyl amido cholanoic acid improves liver glucose and lipid homeostasis in nonalcoholic steatohepatitis via AMPK and mTOR regulation

BACKGROUND

Arachidyl amido cholanoic acid (Aramchol) is a potent downregulator of hepatic stearoyl-CoA desaturase 1 (SCD1) protein expression that reduces liver triglycerides and fibrosis in animal models of steatohepatitis. In a phase IIb clinical trial in patients with nonalcoholic steatohepatitis (NASH), 52 wk of treatment with Aramchol reduced blood levels of glycated hemoglobin A1c, an indicator of glycemic control.

AIM

To assess lipid and glucose metabolism in mouse hepatocytes and in a NASH mouse model [induced with a 0.1% methionine and choline deficient diet (0.1MCD)] after treatment with Aramchol.

METHODS

Isolated primary mouse hepatocytes were incubated with 20 μmol/L Aramchol or vehicle for 48 h. Subsequently, analyses were performed including Western blot, proteomics by mass spectrometry, and fluxomic analysis with 13C-uniformly labeled glucose. For the in vivo part of the study, male C57BL/6J mice were randomly fed a control or 0.1MCD for 4 wk and received 1 or 5 mg/kg/d Aramchol or vehicle by intragastric gavage for the last 2 wk. Liver metabolomics were assessed using ultra-high-performance liquid chromatography-time of flight-MS for the determination of glucose metabolism-related metabolites.

RESULTS

Combination of proteomics and Western blot analyses showed increased AMPK activity while the activity of nutrient sensor mTORC1 was decreased by Aramchol in hepatocytes. This translated into changes in the content of their downstream targets including proteins involved in fatty acid (FA) synthesis and oxidation [P-ACCα/β(S79), SCD1, CPT1A/B, HADHA, and HADHB], oxidative phosphorylation (NDUFA9, NDUFB11, NDUFS1, NDUFV1, ETFDH, and UQCRC2), tricarboxylic acid (TCA) cycle (MDH2, SUCLA2, and SUCLG2), and ribosome (P-p70S6K[T389] and P-S6[S235/S236]). Flux experiments with 13C-uniformely labeled glucose showed that TCA cycle cataplerosis was reduced by Aramchol in hepatocytes, as indicated by the increase in the number of rounds that malate remained in the TCA cycle. Finally, liver metabolomic analysis showed that glucose homeostasis was improved by Aramchol in 0.1MCD fed mice in a dose-dependent manner, showing normalization of glucose, G6P, F6P, UDP-glucose, and Rbl5P/Xyl5P.

CONCLUSION

Aramchol exerts its effect on glucose and lipid metabolism in NASH through activation of AMPK and inhibition of mTORC1, which in turn activate FA β-oxidation and oxidative phosphorylation.

CD4+ T Cells Mediate the Development of Liver Fibrosis in High Fat Diet-Induced NAFLD in Humanized Mice

Non-alcoholic fatty liver disease (NAFLD) has been on a global rise. While animal models have rendered valuable insights to the pathogenesis of NAFLD, discrepancy with patient data still exists. Since non-alcoholic steatohepatitis (NASH) involves chronic inflammation, and CD4⁺ T cell infiltration of the liver is characteristic of NASH patients, we established and characterized a humanized mouse model to identify human-specific immune response(s) associated with NAFLD progression. Immunodeficient mice engrafted with human immune cells (HIL mice) were fed with high fat and high calorie (HFHC) or chow diet for 20 weeks. Liver histology and immune profile of HIL mice were analyzed and compared with patient data. HIL mice on HFHC diet developed steatosis, inflammation and fibrosis of the liver. Human CD4⁺ central and effector memory T cells increased within the liver and in the peripheral blood of our HIL mice, accompanied by marked up-regulation of pro-inflammatory cytokines (IL-17A and IFNγ). In vivo depletion of human CD4⁺ T cells in HIL mice reduced liver inflammation and fibrosis, but not steatosis. Our results highlight CD4⁺ memory T cell subsets as important drivers of NAFLD progression from steatosis to fibrosis and provides a humanized mouse model for pre-clinical evaluation of potential therapeutics.

Arachidonic Acid as an Early Indicator of Inflammation during Non-Alcoholic Fatty Liver Disease Development

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by excessive lipid deposition. Lipid metabolism disturbances are possibly associated with hepatocyte inflammation development and oxidative balance impairment. The aim of our experiment was to examine the first moment when changes in plasma and liver arachidonic acid (AA) levels as a pro-inflammatory precursor may occur during high-fat diet (HFD)-induced NAFLD development. Wistar rats were fed a diet rich in fat for five weeks, and after each week, inflammation and redox balance parameters were evaluated in the liver. The AA contents in lipid fractions were assessed by gas–liquid chromatography (GLC). Protein expression relevant to inflammatory and lipogenesis pathways was determined by immunoblotting. The oxidative system indicators were determined with assay kits. Our results revealed that a high-fat diet promoted an increase in AA levels, especially in the phospholipid (PL) fraction. Importantly, rapid inflammation development via increased inflammatory enzyme expression, elevated lipid peroxidation product content and oxidative system impairment was caused by the HFD as early as the first week of the experiment. Based on these results, we may postulate that changes in AA content may be an early indicator of inflammation and irreversible changes in NAFLD progression.

Hepatoprotective Effect of Antrodia cinnamomea Mycelium in Patients with Nonalcoholic Steatohepatitis: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Nonalcoholic steatohepatitis (NASH) has become a prominent liver disease in contemporary society because of the changing dieting styles. Complicated syndromes often accompanied by obesity and diabetes makes no standard treatment for NASH. Therefore, we investigated the potential role of Antrodia cinnamomea mycelium (ACM) as nutraceutical supplementation in the treatment of NASH in this 6-month randomized, double-blind, placebo-controlled study.

METHOD

28 Participants were treated with three capsules per day containing either 420 mg of ACM or 420 mg of starch as a placebo. The participants were required to follow a predetermined regular visit to hospital every three months during the intervention period (6 months). During each study visit, subjects underwent anthropometric measurements and blood testing for biochemical analysis, immune function assay, inflammatory cytokines assay, and FibroMax test.

RESULTS

The ACM supplemented group had a significant improvement in steatosis and decreased in the inflammatory marker of TNF-α after three and six months. NASH patients who received ACM showed a significant decrease in the SteatoTest mean value from 0.66 at baseline to 0.49 at 6 months (p < 0.029) and the ActiTest mean value decreased from 0.46 at baseline to 0.30 at 6 months (p < 0.029).

CONCLUSION

This is the first clinical investigation that explores the hepatoprotective effect of A. cinnamomea mycelium in patients with NASH. No participants experienced any adverse events during the study, which suggested that ACM is a safe alternative treatment for NASH.