Temporal dynamics of the multi-omic response to endurance exercise training.

Regular exercise promotes whole-body health and prevents disease, but the underlying molecular mechanisms are incompletely understood1-3. Here, the Molecular Transducers of Physical Activity Consortium4 profiled the temporal transcriptome, proteome, metabolome, lipidome, phosphoproteome, acetylproteome, ubiquitylproteome, epigenome and immunome in whole blood, plasma and 18 solid tissues in male and female Rattus norvegicus over eight weeks of endurance exercise training. The resulting data compendium encompasses 9,466 assays across 19 tissues, 25 molecular platforms and 4 training time points. Thousands of shared and tissue-specific molecular alterations were identified, with sex differences found in multiple tissues. Temporal multi-omic and multi-tissue analyses revealed expansive biological insights into the adaptive responses to endurance training, including widespread regulation of immune, metabolic, stress response and mitochondrial pathways. Many changes were relevant to human health, including non-alcoholic fatty liver disease, inflammatory bowel disease, cardiovascular health and tissue injury and recovery. The data and analyses presented in this study will serve as valuable resources for understanding and exploring the multi-tissue molecular effects of endurance training and are provided in a public repository ( https://motrpac-data.org/ ).

Impact of Transgenerational Nutrition on Nonalcoholic Fatty Liver Disease Development: Interplay between Gut Microbiota, Epigenetics and Immunity.

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most prevalent pediatric liver disorder, primarily attributed to dietary shifts in recent years. NAFLD is characterized by the accumulation of lipid species in hepatocytes, leading to liver inflammation that can progress to steatohepatitis, fibrosis, and cirrhosis. Risk factors contributing to NAFLD encompass genetic variations and metabolic disorders such as obesity, diabetes, and insulin resistance. Moreover, transgenerational influences, resulting in an imbalance of gut microbial composition, epigenetic modifications, and dysregulated hepatic immune responses in offspring, play a pivotal role in pediatric NAFLD development. Maternal nutrition shapes the profile of microbiota-derived metabolites in offspring, exerting significant influence on immune system regulation and the development of metabolic syndrome in offspring. In this review, we summarize recent evidence elucidating the intricate interplay between gut microbiota, epigenetics, and immunity in fetuses exposed to maternal nutrition, and its impact on the onset of NAFLD in offspring. Furthermore, potential therapeutic strategies targeting this network are also discussed.

Comprehensive study of the interplay between immunological and metabolic factors in hepatic steatosis.

The pathophysiology of hepatic steatosis is thoroughly reviewed in this comprehensive report, with particular attention to the complex interactions between inflammatory pathways, insulin resistance, lipid metabolism, metabolic dysregulation, and immunological responses in the liver including non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC). The study highlights the role of immune cell regulation in disease progression and explores the potential of immune cell-specific treatments for treating hepatic disorders. The development of liver disorders is significantly influenced by immune cells, including dendritic cells, T cells, and natural killer cells. Clinical investigations show that immune cell-specific treatments can effectively reduce liver fibrosis and inflammation. Future research should focus on finding new immunological targets for therapeutic interventions, as well as addressing the management challenges associated with NAFLD/NASH. Hepatic immune microorganisms also impact liver homeostasis and disorders. Improvements in immune cell regulation and liver transplantation methods give patients hope for better prognoses. Important phases include optimizing the selection of donors for malignancy of the liver, using machine perfusion for organ preservation, and fine-tuning immunosuppressive strategies. For focused treatments in hepatic steatosis, it is imperative to understand the intricate interactions between immune and metabolic variables. Understanding the liver's heterogeneous immune profile, encompassing a range of immune cell subpopulations, is crucial for formulating focused therapeutic interventions. To improve patient care and outcomes in hepatic illnesses, there is an urgent need for further research and innovation. Therefore, to effectively treat hepatic steatosis, it is important to enhance therapeutic techniques and maximize liver transplantation strategies.

Self-recognition through Dectin-1 exacerbates liver inflammation.

Dectin-1 is a well-characterized C-type lectin receptor involved in anti-fungal immunity through the recognition of polysaccharides; however, molecular mechanisms and outcomes initiated through self-recognition have not been fully understood. Here, we purified a water-soluble fraction from mouse liver that acts as a Dectin-1 agonist. To address the physiological relevance of this recognition, we utilized sterile liver inflammation models. The CCl4-induced hepatitis model showed that Dectin-1 deficiency led to reduced inflammation through decreased inflammatory cell infiltration and lower pro-inflammatory cytokine levels. Moreover, in a NASH model induced by streptozotocin and a high-fat diet, hepatic inflammation and fibrosis were ameliorated in Dectin-1-deficient mice. The Dectin-1 agonist activity was increased in the water-soluble fraction from NASH mice, suggesting a potential pathogenic cycle between Dectin-1 activation and hepatitis progression. In vivo administration of the fraction into mice induced hepatic inflammation. These results highlight a role of self-recognition through Dectin-1 that triggers hepatic innate immune responses and contributes to the exacerbation of inflammation in pathogenic settings. Thus, the blockade of this axis may provide a therapeutic option for liver inflammatory diseases.

Cell-specific Deletion of NLRP3 Inflammasome Identifies Myeloid Cells as Key Drivers of Liver Inflammation and Fibrosis in Murine Steatohepatitis.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. The NLRP3 inflammasome, a platform for caspase-1 activation and release of interleukin 1ß, is increasingly recognized in the induction of inflammation and liver fibrosis during NAFLD. However, the cell-specific contribution of NLRP3 inflammasome activation in NAFLD remains unknown. METHODS: To investigate the role of NLRP3 inflammasome activation in hepatocytes, hepatic stellate cells (HSCs) and myeloid cells, a conditional Nlrp3 knock-out mouse was generated and bred to cell-specific Cre mice. Both acute and chronic liver injury models were used: lipopolysaccharide/adenosine-triphosphate to induce in vivo NLRP3 activation, choline-deficient, L-amino acid-defined high-fat diet, and Western-type diet to induce fibrotic nonalcoholic steatohepatitis (NASH). In vitro co-culture studies were performed to dissect the crosstalk between myeloid cells and HSCs. RESULTS: Myeloid-specific deletion of Nlrp3 blunted the systemic and hepatic increase in interleukin 1ß induced by lipopolysaccharide/adenosine-triphosphate injection. In the choline-deficient, L-amino acid-defined high-fat diet model of fibrotic NASH, myeloid-specific Nlrp3 knock-out but not hepatocyte- or HSC-specific knock-out mice showed significant reduction in inflammation independent of steatosis development. Moreover, myeloid-specific Nlrp3 knock-out mice showed ameliorated liver fibrosis and decreased HSC activation. These results were validated in the Western-type diet model. In vitro co-cultured studies with human cell lines demonstrated that HSC can be activated by inflammasome stimulation in monocytes, and this effect was significantly reduced if NLRP3 was downregulated in monocytes. CONCLUSIONS: The study provides new insights in the cell-specific role of NLRP3 in liver inflammation and fibrosis. NLRP3 inflammasome activation in myeloid cells was identified as crucial for the progression of NAFLD to fibrotic NASH. These results may have implications for the development of cell-specific strategies for modulation of NLRP3 activation for treatment of fibrotic NASH.

Hyaluronated and PEGylated Liposomes as a Potential Drug-Delivery Strategy to Specifically Target Liver Cancer and Inflammatory Cells.

Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and is characterized by poor clinical outcomes, with the majority of patients not being eligible for curative therapy and treatments only being applicable for early-stage tumors. CD44 is a receptor for hyaluronic acid (HA) and is involved in HCC progression. The aim of this work is to propose HA- and PEGylated-liposomes as promising approaches for the treatment of HCC. It has been found, in this work, that CD44 transcripts are up-regulated in HCC patients, as well as in a murine model of NAFLD/NASH-related hepatocarcinogenesis. Cell culture experiments indicate that HA-liposomes are more rapidly and significantly internalized by Huh7 cells that over-express CD44, compared with HepG2 cells that express low levels of the receptor, in which the uptake seems due to endocytic events. By contrast, human and murine macrophage cell lines (THP-1, RAW264.7) show improved and rapid uptake of PEG-modified liposomes without the involvement of the CD44. Moreover, the internalization of PEG-modified liposomes seems to induce polarization of THP1 towards the M1 phenotype. In conclusion, data reported in this study indicate that this strategy can be proposed as an alternative for drug delivery and one that dually and specifically targets liver cancer cells and infiltrating tumor macrophages in order to counteract two crucial aspect of HCC progression.

Mechanisms of liver injury in high fat sugar diet fed mice that lack hepatocyte X-box binding protein 1.

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of liver diseases in the United States and can progress to cirrhosis, end-stage liver disease and need for liver transplantation. There are limited therapies for NAFLD, in part, due to incomplete understanding of the disease pathogenesis, which involves different cell populations in the liver. Endoplasmic reticulum stress and its adaptative unfolded protein response (UPR) signaling pathway have been implicated in the progression from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH). We have previously shown that mice lacking the UPR protein X-box binding protein 1 (XBP1) in the liver demonstrated enhanced liver injury and fibrosis in a high fat sugar (HFS) dietary model of NAFLD. In this study, to better understand the role of liver XBP1 in the pathobiology of NAFLD, we fed hepatocyte XBP1 deficient mice a HFS diet or chow and investigated UPR and other cell signaling pathways in hepatocytes, hepatic stellate cells and immune cells. We demonstrate that loss of XBP1 in hepatocytes increased inflammatory pathway expression and altered expression of the UPR signaling in hepatocytes and was associated with enhanced hepatic stellate cell activation after HFS feeding. We believe that a better understanding of liver cell-specific signaling in the pathogenesis of NASH may allow us to identify new therapeutic targets.

Role of macrophage scavenger receptor MSR1 in the progression of non-alcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD), and the dysregulation of lipid metabolism and oxidative stress are the typical features. Subsequent dyslipidemia and oxygen radical production may render the formation of modified lipids. Macrophage scavenger receptor 1 (MSR1) is responsible for the uptake of modified lipoprotein and is one of the key molecules in atherosclerosis. However, the unrestricted uptake of modified lipoproteins by MSR1 and the formation of cholesterol-rich foamy macrophages also can be observed in NASH patients and mouse models. In this review, we highlight the dysregulation of lipid metabolism and oxidative stress in NASH, the alteration of MSR1 expression in physiological and pathological conditions, the formation of modified lipoproteins, and the role of MSR1 on macrophage foaming and NASH development and progression.

Hepatic Macrophages Express Melanoma Differentiation-Associated Gene 5 in Nonalcoholic Steatohepatitis.

The activation of innate immune system is essential for the pathogenesis of nonalcoholic steatohepatitis (NASH). Among pattern recognition receptors, it is well-characterized that toll-like receptors (TLRs) are deeply involved in the development of NASH to reflect exposure of the liver to gut-driven endotoxins. In contrast, it has not been elucidated whether retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) are similarly implicated in the disease progression. In the present study, we examined the expression of melanoma differentiation-associated antigen 5 (MDA5), known to be a member of RLRs, in a diet-induced murine model of NASH. The liver tissues were collected from C57BL/6 J mice at 1, 3, and 6 weeks after choline-deficient L-amino acid-defined high-fat diet (CDAHFD), and the expression of MDA5 was analyzed by western blotting, immunofluorescence (IF), and real-time quantitative PCR (qPCR). The results of western blotting showed that hepatic expression of MDA5 was increased at 3 and 6 weeks. In IF, MDA5-positive cells co-expressed F4/80 and CD11b, indicating they were activated macrophages, and these cells began to appear at 1 week after CDAHFD. The mRNA expression of MDA5 was significantly upregulated at 1 week. Additionally, we performed IF using liver biopsy specimens collected from 11 patients with nonalcoholic fatty liver diseases (NAFLD), and found that MDA5-positive macrophages were detected in eight out of eleven patients. In an in vitro study, MDA5 was induced upon stimulation with lipopolysaccharide in murine bone marrow-derived macrophages and THP-1 cells. Our findings suggest that MDA5 may be involved in the inflammation of NASH.

The Detrimental Role of Regulatory T Cells in Nonalcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is induced by steatosis and metabolic inflammation. While involvement of the innate immune response has been shown, the role of the adaptive immune response in NASH remains controversial. Likewise, the role of regulatory T cells (Treg) in NASH remains unclear although initial clinical trials aim to target these regulatory responses. High-fat high-carbohydrate (HF-HC) diet feeding of NASH-resistant BALB/c mice as well as the corresponding recombination activating 1 (Rag)-deficient strain was used to induce NASH and to study the role of the adaptive immune response. HF-HC diet feeding induced strong activation of intrahepatic T cells in BALB/c mice, suggesting an antigen-driven effect. In contrast, the effects of the absence of the adaptive immune response was notable. NASH in BALB/c Rag1-/- mice was substantially worsened and accompanied by a sharp increase of M1-like macrophage numbers. Furthermore, we found an increase in intrahepatic Treg numbers in NASH, but either adoptive Treg transfer or anti-cluster of differentiation (CD)3 therapy unexpectedly increased steatosis and the alanine aminotransferase level without otherwise affecting NASH. Conclusion: Although intrahepatic T cells were activated and marginally clonally expanded in NASH, these effects were counterbalanced by increased Treg numbers. The ablation of adaptive immunity in murine NASH led to marked aggravation of NASH, suggesting that Tregs are not regulators of metabolic inflammation but rather enhance it.

Hepatocyte-specific deletion of adipose triglyceride lipase (adipose triglyceride lipase/patatin-like phospholipase domain containing 2) ameliorates dietary induced steatohepatitis in mice.

BACKGROUND AND AIMS: Increased fatty acid (FA) flux from adipose tissue to the liver contributes to the development of NAFLD. Because free FAs are key lipotoxic triggers accelerating disease progression, inhibiting adipose triglyceride lipase (ATGL)/patatin-like phospholipase domain containing 2 (PNPLA2), the main enzyme driving lipolysis, may attenuate steatohepatitis. APPROACH AND RESULTS: Hepatocyte-specific ATGL knockout (ATGL LKO) mice were challenged with methionine-choline-deficient (MCD) or high-fat high-carbohydrate (HFHC) diet. Serum biochemistry, hepatic lipid content and liver histology were assessed. Mechanistically, hepatic gene and protein expression of lipid metabolism, inflammation, fibrosis, apoptosis, and endoplasmic reticulum (ER) stress markers were investigated. DNA binding activity for peroxisome proliferator-activated receptor (PPAR) α and PPARδ was measured. After short hairpin RNA-mediated ATGL knockdown, HepG2 cells were treated with lipopolysaccharide (LPS) or oleic acid:palmitic acid 2:1 (OP21) to explore the direct role of ATGL in inflammation in vitro. On MCD and HFHC challenge, ATGL LKO mice showed reduced PPARα and increased PPARδ DNA binding activity when compared with challenged wild-type (WT) mice. Despite histologically and biochemically pronounced hepatic steatosis, dietary-challenged ATGL LKO mice showed lower hepatic inflammation, reflected by the reduced number of Galectin3/MAC-2 and myeloperoxidase-positive cells and low mRNA expression levels of inflammatory markers (such as IL-1ß and F4/80) when compared with WT mice. In line with this, protein levels of the ER stress markers protein kinase R-like endoplasmic reticulum kinase and inositol-requiring enzyme 1α were reduced in ATGL LKO mice fed with MCD diet. Accordingly, pretreatment of LPS-treated HepG2 cells with the PPARδ agonist GW0742 suppressed mRNA expression of inflammatory markers. Additionally, ATGL knockdown in HepG2 cells attenuated LPS/OP21-induced expression of proinflammatory cytokines and chemokines such as chemokine (C-X-C motif) ligand 5, chemokine (C-C motif) ligand (Ccl) 2, and Ccl5. CONCLUSIONS: Low hepatic lipolysis and increased PPARδ activity in ATGL/PNPLA2 deficiency may counteract hepatic inflammation and ER stress despite increased steatosis. Therefore, lowering hepatocyte lipolysis through ATGL inhibition represents a promising therapeutic strategy for the treatment of steatohepatitis.

Hepatic Macrophage as a Key Player in Fatty Liver Disease.

Fatty liver disease, characterized by excessive inflammation and lipid deposition, is becoming one of the most prevalent liver metabolic diseases worldwide owing to the increasing global incidence of obesity. However, the underlying mechanisms of fatty liver disease are poorly understood. Accumulating evidence suggests that hepatic macrophages, specifically Kupffer cells (KCs), act as key players in the progression of fatty liver disease. Thus, it is essential to examine the current evidence of the roles of hepatic macrophages (both KCs and monocyte-derived macrophages). In this review, we primarily address the heterogeneities and multiple patterns of hepatic macrophages participating in the pathogenesis of fatty liver disease, including Toll-like receptors (TLRs), NLRP3 inflammasome, lipotoxicity, glucotoxicity, metabolic reprogramming, interaction with surrounding cells in the liver, and iron poisoning. A better understanding of the diverse roles of hepatic macrophages in the development of fatty liver disease may provide a more specific and promising macrophage-targeting therapeutic strategy for inflammatory liver diseases.

Analysis of Common Pathways and Markers From Non-Alcoholic Fatty Liver Disease to Immune-Mediated Diseases.

Metabolic associated fatty liver disease (MAFLD) is the most prevalent form of liver disease worldwide, accounting for a high liver-related mortality and morbidity with extensive multi-organ involvement. This entity has displaced viral hepatitis as the main cause of severe forms of hepatic diseases, although the onset and transition of MAFLD stages still remains unclear. Nevertheless, innate and adaptive immune responses seem to play an essential role in the establishment and further progression of this disease. The immune system is responsible of safeguard and preserves organs and systems function, and might be altered under different stimuli. Thus, the liver suffers from metabolic and immune changes leading to different injuries and loss of function. It has been stablished that cell-cell crosstalk is a key process in the hepatic homeostasis maintenance. There is mounting evidence suggesting that MAFLD pathogenesis is determined by a complex interaction of environmental, genetic and host factors that leads to a full plethora of outcomes. Therefore, herein we will revisit and discuss the interplay between immune mechanisms and MAFLD, highlighting the potential role of immunological markers in an attempt to clarify its relationship.

Jiang Zhi Granule protects immunological barrier of intestinal mucosa in rats with non-alcoholic steatohepatitis.

CONTEXT: Jiang Zhi Granule (JZG) is known to improve hepatic function, reduce liver fat deposition and inflammation in non-alcoholic fatty liver disease (NAFLD). OBJECTIVE: To determine the protective mechanism of JZG on immunological barrier of intestinal mucosa in rats with diet-induced non-alcoholic steatohepatitis (NASH). MATERIALS AND METHODS: A Sprague-Dawley (SD) model of NASH was established using a high-fat diet and 1% dextran sulphate sodium (DSS) through drinking water. The rats were randomized into four groups and treated for four weeks, respectively, including normal control (NC), model control (MC), positive control (PC) and JZG. Mesenteric lymph nodes (MLNs) cells were isolated and cultured to assess a potential disruption of the enteric immune barrier. Also, investigation of intestinal mucosal dendritic cell-toll-like-receptor-myeloid differentiation primary response 88 (DC-TLR-MyD88) signalling pathway in vitro was examined. RESULTS: The lethal concentration 50 (LD50) of JZG was greater than 5 g/kg, while its inhibitory concentration 50 (IC50) was 1359 µg/mL in HepG2. In JZG group, the plasma levels of alanine transaminase (ALT), aspartate transaminase (AST), malondialdehyde (MDA), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglyceride (TG) and serum endotoxin were significantly (p < 0.01) reduced. In contrast, plasma concentrations of high-density lipoprotein cholesterol (HDL-C) and superoxide dismutase (SOD) were increased. Furthermore, proinflammatory factor, interferon-γ (IFN-γ)+ from CD4+ T cells in DSS-induced NASH rats increased significantly (p < 0.01) compared to NC group. Importantly, JZG treatment substantially decreased (p < 0.01) the relative expressions of TLR-44 and MyD88. CONCLUSIONS: JZG treatment may protect immunological barrier of intestinal mucosa in NASH individual.

T Cell Subsets and Natural Killer Cells in the Pathogenesis of Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is a condition characterized by hepatic accumulation of excess lipids. T cells are commonly classified into various subsets based on their surface markers including T cell receptors, type of antigen presentation and pathophysiological functions. Several studies have implicated various T cell subsets and natural killer (NK) cells in the progression of NAFLD. While NK cells are mainly components of the innate hepatic immune system, the majority of T cell subsets can be part of both the adaptive and innate systems. Several studies have reported that various stages of NAFLD are accompanied by the accumulation of distinct T cell subsets and NK cells with different functions and phenotypes observed usually resulting in proinflammatory effects. More importantly, the overall stimulation of the intrahepatic T cell subsets is directly influenced by the homeostasis of the gut microbiota. Similarly, NK cells have been found to accumulate in the liver in response to pathogens and tumors. In this review, we discussed the nature and pathophysiological roles of T cell subsets including γδ T cells, NKT cells, Mucosal-associated invariant T (MAIT) cells as well as NK cells in NAFLD.

Mangiferin Ameliorates HFD-Induced NAFLD through Regulation of the AMPK and NLRP3 Inflammasome Signal Pathways.

Nonalcoholic fatty liver disease (NAFLD) is closely related to glycolipid metabolism and liver inflammation. And there is no effective drug approved for its clinical therapy. In this study, we focused on mangiferin (Man) and explored its effects and mechanisms on NAFLD treatment based on the regulation of glycolipid metabolism and anti-inflammatory in vivo and in vitro. The results exhibited that Man can significantly attenuate liver injury, insulin resistance, and glucose tolerance in high-fat diet- (HFD-) induced NAFLD mice and significantly reduce fat accumulation and inflammation in hepatic tissue of NAFLD mice. The transcriptome level RNA-seq analysis showed that the significantly different expression genes between the Man treatment group and the HFD-induced NAFLD model group were mainly related to regulation of energy, metabolism, and inflammation in liver tissue. Furthermore, western blots, real-time PCR, and immunohistochemistry experiments confirmed that Man significantly activated the AMPK signal pathway and inhibited NLRP3 inflammasome activation and pyroptosis in NAFLD mice. In in vitro cell experiments, we further confirmed that Man can promote glucose consumption and reduce intracellular triglyceride (TG) accumulation induced by free fatty acids in HepG2 cells and further that it can be blocked by AMPK-specific inhibitors. Western blot results showed that Man upregulated p-AMPKα levels and exhibited a significant AMPK activation effect, which was blocked by compound C. At the same time, Man downregulated the expression of NLRP3 inflammasome-related proteins and inhibited the activation of NLRP3 inflammasome, alleviating cell pyroptosis and inflammation effects. These results indicate that Man anti-NAFLD activity is mediated through its regulation of glucolipid metabolism by AMPK activation and its anti-inflammatory effects by NLRP3 inflammasome inhibition. Our study indicates that Man is a promising prodrug for the therapy of NAFLD patients.

Emerging Roles of T Cells in the Pathogenesis of Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma.

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. A significant proportion of patients with NAFLD develop a progressive inflammatory condition termed nonalcoholic steatohepatitis (NASH), which may eventually advance to cirrhosis and hepatocellular carcinoma (HCC). NASH is characterized by steatosis, hepatocyte ballooning, and lobular inflammation. Heightened immune cell infiltration is a hallmark of NASH, yet the mechanisms whereby hepatic inflammation occurs in NASH and how it contributes to disease initiation and progression remain incompletely understood. Emerging evidence indicates that intrahepatic T cell immune mechanisms play an integral role in the pathogenesis of NASH and its transition to HCC. In this review, we summarize the current knowledge regarding the T cell-mediated mechanisms of inflammation in NASH. We highlight recent preclinical and human studies implicating various subsets of conventional and innate-like T cells in the onset and progression of NASH and HCC. Finally, we discuss the potential therapeutic strategies targeting T cell-mediated responses for the treatment of NASH.

Tim-1 Deficiency Aggravates High-Fat Diet-Induced Steatohepatitis in Mice.

Non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is commonly associated with obesity and characterized by excessive lipid accumulation and liver inflammation. The T cell immunoglobulin and mucin domain 1 (Tim-1), also known as hepatitis A virus cellular receptor 1 (Havcr-1) and kidney injury molecule 1 (Kim-1), has been shown to affect innate immunity-driven proinflammatory cascade in liver ischemia-reperfusion injury. However, its contribution to obesity-related NAFLD/NASH remains unknown. Thus, this study was designed to evaluate the role of Tim-1 in obesity-related liver inflammation and injury in wild-type (WT) and Tim-1-deficient (Tim-1-/-) C57BL/6J mice fed a high-fat diet (HFD) for 5-6 months. HFD feeding induced steatosis and upregulated Tim-1 gene expression in the liver of WT mice. Surprisingly, Tim-1-/- mice on HFD diet exhibited an exacerbation of hepatic steatosis, accompanied with an elevation of protein levels of fatty acid translocase CD36 and sterol regulatory element binding protein 1 (SREBP1). Tim-1 deficiency also enhanced HFD-induced liver inflammation and injury, as evidenced by augmented increase in hepatic expression of pro-inflammatory factor lipocalin 2 and elevated serum alanine transaminase (ALT). In addition, gene expression of type I, III and IV collagens and liver fibrosis were greatly enhanced in HFD Tim-1-/- mice compared with HFD WT mice. HFD-induced hepatic expression of YM-1, a specific mouse M2 macrophage marker, was further upregulated by deletion of Tim-1. Together, these results show that Tim-1 deficiency aggravates the effects of HFD diet on lipid accumulation and liver fibrosis, most likely through enhanced infiltration and activation of inflammatory cells.

Jiangzhi Granule attenuates non-alcoholic steatohepatitis by suppressing TNF/NFκB signaling pathway-a study based on network pharmacology.

Jiangzhi Granule is a commonly used traditional Chinese medicine for treating non-alcoholic fatty liver disease. However, its key ingredients and underlying mechanisms for attenuating nonalcoholic steatohepatitis (NASH) remain unclear. To address this issue, UPLC-TOF-MS based chemical profiling, network pharmacology and animal experimental validation were employed. First, a total of 56 main ingredients of Jiangzhi Granule and 38 ingredients in the blood and liver (after oral administration) were identified. Then, 170 potential targets of the absorbed ingredients and 50 targets of NASH were identified, and 10 overlapped genes were identified as candidate targets of Jiangzhi Granule for NASH treatment. A Jiangzhi Granule-ingredients-targets-disease network was constructed using Cytoscape software, which included eight main ingredients (such as emodin, resveratrol and quercetin) and 10 candidate targets (such as TNF, IL6 and CCL2). Functional enrichment indicated that the candidate targets were enriched in multiple pathways (such as the TNF signaling pathway). Furthermore, a NASH mice model was constructed and intervened with Jiangzhi Granule. The results revealed that Jiangzhi Granule could ameliorate NASH characteristics, such as histopathological changes and liver cholesterol level. Meanwhile, Jiangzhi Granule significantly decreased the mRNA and protein expression of TNFα in NASH mice liver, suppressed NFκB activation, and inhibited the expression of macrophage activation marker F4/80 and M1-type polarization marker CD11b/CD11c. ELISA assay indicated that Jiangzhi Granule reduced pro-inflammatory cytokines (including TNFα, IL-1ß and IL-6) in the liver. Collectively, our results suggested that Jiangzhi Granule could attenuate NASH by suppressing TNF/NFκB signaling mediated macrophage M1-type polarization.

Accumulation of Toxic Advanced Glycation End-Products Induces Cytotoxicity and Inflammation in Hepatocyte-Like Cells Differentiated from Human Induced Pluripotent Stem Cells.

Nonalcoholic steatohepatitis (NASH), the aggressive form of the most common chronic liver disease nonalcoholic fatty liver disease, is characterized by inflammation and damage in the liver. Although hepatocyte injury and cell death have been identified as cardinal pathological features of NASH, its pathogenesis has not yet been elucidated in detail. Immortalized cell lines and primary cultured cells have been used as in vitro models of NASH. However, these cells have several disadvantages, such as specialized characteristics by immortalization or limited growth potential. To overcome these difficulties and develop a strategy to analyze the pathology of NASH, we employed hepatocyte-like cells differentiated from human induced pluripotent stem cells (hiPSC-HLCs) as an in vitro model of NASH to clarify the intracellular effects of glyceraldehyde-derived advanced glycation end-products (AGEs), also named toxic AGEs (TAGE). The viability of hiPSC-HLCs decreased with the accumulation of TAGE in the cells, which was consistent with previous findings on human hepatocellular carcinoma cells and human primary cultured hepatocytes. In addition, the TAGE accumulation up-regulated the expression of inflammation-related genes (interleukin 6, interleukin 8, and monocyte chemoattractant protein-1) in hiPSC-HLCs. These results indicated that the accumulation of TAGE induced hiPSC-HLC cytotoxicity and inflammation, which are features of the pathology of NASH. Therefore, we suggest the use of hiPSC-HLCs as an important strategy for analyses of the pathology of NASH.