Animal Model Of Nonalcoholic Steatohepatitis Research Articles

MicroRNA-29a Disrupts DNMT3b to Ameliorate Diet-Induced Non-Alcoholic Steatohepatitis in Mice.

MicroRNA-29 (miR-29) has been found to reduce liver inflammation and fibrosis following a liver injury. Meanwhile, DNA methyltransferase has been reported to participate in the development of non-alcoholic steatohepatitis (NASH). The aim of this study is to investigate the miR-29a regulation of methyltransferase signaling and epigenetic program in NASH progression. Methods: miR-29a transgenic mice (miR-29aTg mice) and wild-type littermates were subjected to the methionine-choline-deficient (MCD) diet-induced animal model of NASH. Primary hepatic stellate cells were transfected with a miR-29a mimic and antisense inhibitor. We then analyzed gene expressions with qRT-PCR, immunohistochemical stain, Western blot, and luciferase reporter assay. The results demonstrated that increased miR-29a alleviated the MCD diet-induced body weight loss and steatosis and decreased aspartate aminotransferase (AST) levels in mice. Furthermore, hepatic tissue in miR-29aTg mice displayed a weak fibrotic matrix, as shown with Sirius Red staining concomitant with low fibrotic α-SMA expression within affected tissues compared to the wild-type mice fed the MCD diet. Forced miR-29a expression reduced the MCD diet exaggeration of reactive oxygen species (ROS) production by immunohistochemically staining 8-OHdG. Increased miR-29a signaling also resulted in the downregulation of DNMT3b, TGF-β, IL-6, heme oxygenase-1 (HO-1), p-SMAD3, PI3K, and L3BII expression within the liver tissue. An in vitro luciferase reporter assay further confirmed that miR-29a mimic transfection reduced DNMT3b expression in primary HSCs. Our data provide new insights that miR-29a improves MCD diet-induced liver inflammation, steatosis and fibrosis, and highlight the potential of miR-29a targeted therapy for treating NASH.

MiR-218-XOR-ROS Pathway Regulates the Progression of Nonalcoholic Steatohepatitis.

To investigate the role of the miR-218-xanthine oxidoreductase (XOR) pathway in the pathogenesis of nonalcoholic steatohepatitis (NASH) and to explore the potential downstream mechanisms involving oxidative stress and energy metabolism. The NASH animal model was established by feeding BALB/c mice with an MCD diet, while BRL-3A cells were cultured with a mixture of oleate and palmitate for 72 hours to mimic the steatosis and inflammation of NASH in vitro. The steatosis and inflammation levels were assessed by H-E/oil-red staining and serum/supernatant TG, ALT, and AST levels. The apoptosis degree was tested by the TUNEL/flow cytometry method both in animals and cultured cells. The XOR and miR-218 levels were detected by western blotting and qRT-PCR. Decreased miR-218 and increased XOR levels were identified in the NASH animal and cell models, while the regulation of miR-218 on XOR was also confirmed. NASH alleviation was achieved after miR-218 over-expression in vivo and in vitro, according to the declination of steatosis and inflammation-related markers. Although H2O2 and ATP levels were increased and decreased in NASH models, respectively, antagonizing miR-218 could significantly alleviate those changes. The miR-218-XOR pathway may provide a novel mechanism and treatment option for NASH.

Combining probiotics and an angiotensin-II type 1 receptor blocker has beneficial effects on hepatic fibrogenesis in a rat model of non-alcoholic steatohepatitis.

Intestinal endotoxin is important for the progression of non-alcoholic steatohepatitis (NASH). Circulating endotoxin levels are elevated in most animal models of diet-induced non-alcoholic fatty liver disease (NAFLD) and NASH. Furthermore, plasma endotoxin levels are significantly higher in NAFLD patients, which is associated with small intestinal bacterial overgrowth and increased intestinal permeability. By improving the gut microbiota environment and restoring gut-barrier functions, probiotics are effective for NASH treatment in animal models. It is also widely known that hepatic fibrosis and suppression of activated hepatic stellate cells (Ac-HSCs) can be attenuated using an angiotensin-II type 1 receptor blocker (ARB). We thus evaluated the effect of combination probiotics and ARB treatment on liver fibrosis using a rat model of NASH. Fisher 344 rats were fed a choline-deficient/L-amino acid-defined (CDAA) diet for 8weeks to generate the NASH model. Animals were divided into ARB, probiotics, and ARB plus probiotics groups. Therapeutic efficacy was assessed by evaluating liver fibrosis, the lipopolysaccharide Toll-like receptor (TLR)4 regulatory cascade, and intestinal barrier function. Both probiotics and ARB inhibited liver fibrosis, with concomitant HSC activation and suppression of liver-specific transforming growth factor-β and TLR4 expression. Probiotics reduced intestinal permeability by rescuing zonula occludens-1 disruption induced by the CDAA diet. Angiotensin-II type 1 receptor blocker was found to directly suppress Ac-HSCs. Probiotics and ARB are effective in suppressing liver fibrosis through different mechanisms. Currently both drugs are in clinical use; therefore, the combination of probiotics and ARB is a promising new therapy for NASH.

Disease Progression and Pharmacological Intervention in a Nutrient-Deficient Rat Model of Nonalcoholic Steatohepatitis

BackgroundThere is a marked need for improved animal models of nonalcoholic steatohepatitis (NASH) to facilitate the development of more efficacious drug therapies for the disease.MethodsHere, we investigated the development of fibrotic NASH in male Wistar rats fed a choline-deficient l-amino acid-defined (CDAA) diet with or without cholesterol supplementation for subsequent assessment of drug treatment efficacy in NASH biopsy-confirmed rats. The metabolic profile and liver histopathology were evaluated after 4, 8, and 12 weeks of dieting. Subsequently, rats with biopsy-confirmed NASH were selected for pharmacological intervention with vehicle, elafibranor (30 mg/kg/day) or obeticholic acid (OCA, 30 mg/kg/day) for 5 weeks.ResultsThe CDAA diet led to marked hepatomegaly and fibrosis already after 4 weeks of feeding, with further progression of collagen deposition and fibrogenesis-associated gene expression during the 12-week feeding period. Cholesterol supplementation enhanced the stimulatory effect of CDAA on gene transcripts associated with fibrogenesis without significantly increasing collagen deposition. Pharmacological intervention with elafibranor, but not OCA, significantly reduced steatohepatitis scores, and fibrosis-associated gene expression, however, was unable to prevent progression in fibrosis scores.ConclusionCDAA-fed rats develop early-onset progressive NASH, which offers the opportunity to probe anti-NASH compounds with potential disease-modifying properties.

Non-alcoholic Steatohepatitis (NASH) Drug Discovery - Building a Consensus on ADME Screening Tools and Clinical Pharmacology Strategies to Aid Candidate Development.

Number of drugs with different mechanisms of actions is undergoing clinical trials for non-alcoholic steatohepatitis (NASH). Given the complexity of the disease with respect to pathophysiology in the liver and associated changes in the renal function, it becomes apparent that a clear ADME (absorption, distribution, metabolism and excretion) strategy needs to be put in place for a successful nomination of a drug candidate for NASH. This review discusses using in vitro and in vivo ADME screens to understand the properties of drugs and to establish whether or not the chosen drug(s) can overcome the challenges related hepatic and renal transporters covering both uptake and efflux mechanisms imposed by NASH. A complete panel of in vivo preclinical experiments including a 14C-labeled study are proposed in NASH animal models to delineate the problematic areas for early drug development. Furthermore, a framework is provided with respect to the clinical pharmacology studies early in clinical development to characterise in an unbiased manner, the altered pharmacokinetics of drug in NASH patients for optimizing the dose selection for late phase clinical development. Because NASH patients have other co-morbid conditions and are prescribed co-medications for treating blood pressure, type 2 diabetes mellitus, obesity, dyslipidemia and many more disorders, it is also suggested to examine the drug-drug interaction potential by performing a cocktail probe study to cover a broad range of cytochrome P450 (CYP) enzymes and transporters.

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

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

Urea cycle dysregulation in non-alcoholic fatty liver disease

In non-alcoholic steatohepatitis (NASH), the function of urea cycle enzymes (UCEs) may be affected, resulting in hyperammonemia and the risk of disease progression. We aimed to determine whether the expression and function of UCEs are altered in an animal model of NASH and in patients with non-alcoholic fatty liver disease (NAFLD), and whether this process is reversible. Rats were first fed a high-fat, high-cholesterol diet for 10 months to induce NASH, before being switched onto a normal chow diet to recover. In humans, we obtained liver biopsies from 20 patients with steatosis and 15 with NASH. Primary rat hepatocytes were isolated and cultured with free fatty acids. We measured the gene and protein expression of ornithine transcarbamylase (OTC) and carbamoylphosphate synthetase (CPS1), as well as OTC activity, and ammonia concentrations. Moreover, we assessed the promoter methylation status of OTC and CPS1 in rats, humans and steatotic hepatocytes. In NASH animals, gene and protein expression of OTC and CPS1, and the activity of OTC, were reversibly reduced. Hypermethylation of Otc promoter genes was also observed. Additionally, in patients with NAFLD, OTC enzyme concentration and activity were reduced and ammonia concentrations were increased, which was further exacerbated in those with NASH. Furthermore, OTC and CPS1 promoter regions were hypermethylated. In primary hepatocytes, induction of steatosis was associated with Otc promoter hypermethylation, a reduction in the gene expression of Otc and Cps1, and an increase in ammonia concentration in the supernatant. NASH is associated with a reduction in the gene and protein expression, and activity, of UCEs. This results in hyperammonemia, possibly through hypermethylation of UCE genes and impairment of urea synthesis. Our investigations are the first to describe a link between NASH, the function of UCEs, and hyperammonemia, providing a novel therapeutic target. In patients with fatty liver disease, the enzymes that convert nitrogen waste into urea may be affected, leading to the accumulation of ammonia, which is toxic. This accumulation of ammonia can lead to scar tissue development, increasing the risk of disease progression. In this study, we show that fat accumulation in the liver produces a reversible reduction in the function of the enzymes that are involved in detoxification of ammonia. These data provide potential new targets for the treatment of fatty liver disease.

Effect of a Novel Long-Acting GLP-1/GIP/Glucagon Triple Agonist (HM15211) in a NASH and Fibrosis Animal Model

Nonalcoholic steatohepatitis (NASH), a potential consequence of NAFLD, may lead to end stage liver disease including cirrhosis and hepatocellular carcinoma. Despite its severity and prevalence, NASH currently lacks effective treatment. In this respect, we developed a novel long-acting, GLP-1/GIP/Glucagon triple agonist, HM15211. With a unique activity profile, HM15211 could provide synergistic benefits on body weight loss and lipid profile improvement while avoiding hyperglycemic risk. Previously, we showed that HM15211 exerts potent reductions in body weight and hepatic TG (triglycerides) in DIO mice, and showed a liver preferential distribution, suggesting HM15211 as a potential treatment for NASH. Here, we evaluated the effect of HM15211 in NASH and fibrosis using MCD-diet mice with various disease induction periods. In MCD-diet mice (6 weeks induction), HM15211 treatment led to significant decrease in hepatic TG (-82.6% vs. vehicle) and TBARS (oxidative stress marker, -60.7% vs. vehicle), which coincided with significant reduction in ALT and bilirubin. Time course MRI/MRS imaging further confirmed the progressive steatosis resolution by HM15211. Furthermore, histopathological analysis indicated that HM15211 significantly reduced hepatic inflammatory gene expression and NAFLD activity score (1.3 for HM15211, 3.4 for liraglutide, and 2.7 for vehicle). To further evaluate the therapeutic potential in fibrosis, MCD-diet mice was used for an extended period (10 weeks induction) to achieve overt liver fibrosis. In line with NASH improvement, HM15211 successfully resolved liver fibrosis as demonstrated in histological evaluation. Histological improvements were accompanied by a remarkable decrease in disease biomarkers including hepatic hydroxyproline. Based on these observations, HM15211 may offer a therapeutic potential for NASH and fibrosis as well as obesity. Disclosure I. Choi: Employee; Self; Hanmi Pharmaceutical. Stock/Shareholder; Self; Hanmi Pharmaceutical. J. Kim: Employee; Self; Hanmi Pharmaceutical. Stock/Shareholder; Self; Hanmi Pharmaceutical. J. Lee: Employee; Self; Hanmi Pharmaceutical. Stock/Shareholder; Self; Hanmi Pharmaceutical. E. Park: Employee; Self; Hanmi Pharmaceutical. Y. Kim: Employee; Self; Hanmi Pharmaceutical. S. Jung: None. S. Kim: Employee; Self; Hanmi Pharmaceutical. Stock/Shareholder; Self; Hanmi Pharmaceutical.

Progression and Regression of Hepatic Lesions in a Mouse Model of NASH Induced by Dietary Intervention and Its Implications in Pharmacotherapy.

Understanding of the temporal changes of hepatic lesions in the progression and regression of non-alcoholic steatohepatitis (NASH) is vital to elucidation of the pathogenesis of NASH, and critical to the development of a strategy for NASH pharmacotherapy. There are challenges in studying hepatic lesion progression and regression in NASH patients due to the slow development of NASH in humans, one being the requirement for multiple biopsies during the longitudinal follow-up. Here we studied lesion progression and regression in the diet-induced animal model of NASH by application or removal of the pathogenic diet for multiple time periods. Male C57BL/6 mice fed Western diet developed progressive hepatic steatosis/macrovesicular vacuolation, inflammation, and hepatocyte degeneration, as well as perisinusoidal fibrosis and occasionally portal fibrosis as early as 2 months after initiation of the Western diet. In the same period, the mice exhibited elevated ALT (alanine aminotransferase) and AST (aspartate aminotransferase) enzyme activities, CK18 (cytokeratin−18), PIIINP (N-terminal propeptide of type III collagen), and TIMP-1 (tissue inhibitor of metalloproteinase−1). Hepatic steatosis diminished rapidly when the Western diet was replaced by normal rodent chow diet and hepatic inflammation and hepatocyte degeneration were also reduced. Interestingly, perisinusoidal fibrosis and portal fibrosis regressed 8 months after chow diet replacement. To understand pharmacotherapy for NASH, mice with established NASH hepatic lesions were treated with either FXR agonist obeticholic acid (Ocaliva), or CCR2/5 antagonist Cenicriviroc. Similar to the diet replacement, metabolic modulator Ocaliva markedly reduced steatosis/macrovesicular vacuolation, hepatic inflammation, and hepatocyte degeneration effectively, but exhibited no significant effect on liver fibrosis. Anti-inflammation drug Cenicriviroc, on the other hand, markedly decreased inflammation and hepatocyte degeneration, and mildly decreased liver fibrosis, but exhibited no effect on hepatic steatosis/macrovesicular vacuolation. In conclusion, we found the progression of NASH hepatic steatosis/macrovesicular vacuolation, and inflammation eventually lead to hepatocyte death and fibrosis. Life style change and current pharmacotherapies in development may be effective in treating NASH, but their effects on NASH–induced fibrosis may be mild. Since fibrosis is known to be an independent risk for decompensated cirrhosis, cardiovascular events, and mortality, our study suggests that effective anti-fibrosis therapy should be an essential component of the combined pharmacotherapy for advanced NASH.

Growth differentiation factor 15 ameliorates nonalcoholic steatohepatitis and related metabolic disorders in mice

Growth differentiation factor 15 (GDF15) is an endocrine hormone belonging to the TGFβ superfamily member. GDF15 administration or GDF15 overexpression has been reported to have anti-obesity and anti-diabetic effects. Although non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is frequently associated with obesity and insulin resistance, the functional role of endogenous GDF15 and therapeutic effect of GDF15 overexpression in NASH and related metabolic deterioration have not been evaluated. Here, we found that GDF15 expression was increased in the livers of NASH animal models and human subjects with NASH. Elevated expression of GDF15 was due to diet-induced hepatic endoplasmic reticulum (ER) stress. Gdf15-knockout mice exhibited aggravated NASH phenotypes such as increased steatosis, hepatic inflammation, fibrosis, liver injury, and metabolic deterioration. Furthermore, GDF15 directly suppressed expression of fibrosis-related genes and osteopontin (OPN), contributing factors for NASH-related fibrosis, in hepatic stellate cells in vitro and in the liver of mice in vivo. Finally, we found that GDF15-transgenic mice showed attenuation of NASH phenotypes and metabolic deterioration. Therefore, our results suggest that induction of endogenous GDF15 is a compensatory mechanism to protect against the progression of NASH and that GDF15 could be an attractive therapeutic candidate for treatment of NASH and NASH-related metabolic deterioration.

Mouse models of non-alcoholic steatohepatitis: A reflection on recent literature.

Non-alcoholic steatohepatitis (NASH) is strongly associated with overnutrition, insulin resistance, and predisposition to type 2 diabetes. To critically analyze the translational significance of currently used animal models of NASH, we reviewed articles published during the last 3years that studied NASH pathogenesis using mouse models. Among 146 articles, 34 (23%) used models in which overnutrition was reported, and 36 (25%) demonstrated insulin resistance, with or without glucose intolerance. Half the articles contained no information on whether mice exhibited overnutrition or insulin resistance. While 75 papers (52%) reported >2-fold increase of serum/plasma alanine aminotransferase (ALT) compared with controls, ALT levels were near normal or not reported in 48%. Liver pathology was assessed by a pathologist with an interest in liver pathology in 53% of articles published in gastroenterology/hepatology journals, versus 43-44% in other journals. While there appears to be a trend to use models that are potentially relevant to the pathogenesis of human NASH, journals currently publish data on mouse models in which overnutrition and insulin resistance do not occur, without ALT increase or appropriate analysis of NASH pathology. We recommend that investigators, reviewers, and journal editors carefully consider the validity of NASH models in current use and that moves are made to reach a consensus on what the minimal criteria should be.

Chymase Inhibitor as a Novel Therapeutic Agent for Non-alcoholic Steatohepatitis.

Non-alcoholic steatohepatitis (NASH) is characterized by inflammation and fibrosis, in addition to steatosis, of the liver, but no therapeutic agents have yet been established. The mast cell protease chymase can generate angiotensin II, matrix metalloproteinase-9 and transforming growth factor-β, all of which are associated with liver inflammation or fibrosis. In animal models of NASH, augmented chymase has been observed in the liver. In histological analysis, chymase inhibitor prevented hepatic steatosis, inflammation, and fibrosis. Chymase inhibitor also attenuated the augmentation of angiotensin II, matrix metalloproteinase-9, and transforming growth factor-β observed in the liver of NASH. Oxidative stress, inflammatory markers, and collagen were attenuated by chymase inhibition. Moreover, chymase inhibitor showed a mitigating effect on established NASH, and survival rates were significantly increased by treatment with chymase inhibitor. In this review, we propose that chymase inhibitor has potential as a novel therapy for NASH.

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

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

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MMR hypermutations (from Mouradov, Cancer Res 2014;74:3238)More than 80,000 adult and childhood tumors were examined for mutation frequencies across tumor types and the contribution of intrinsic and extrinsic mutators. The data allowed the prediction of past mutagen exposure and the identification of new drivers of hypermutator phenotypes, including prior chemotherapy. The order of mutational signatures leading to hypermutation was deduced, providing potential insights into tumor classification, patient management, and genetic testing.Campbell BB, …, Shlien A. Cell 2017 Nov 16;171:1042–1056.e10.Intestinal flora (from Bonnet, Clin Can Res 2014;20:859)Two clinical studies confirm mouse models that suggested that responses to anti–PD-1 therapy in patients with melanoma (Gopalakrishnan et al.) or kidney, lung, or bladder tumors (Routy et al.) correlate with gut microbiome composition. Antibiotics before or during therapy hastened relapse and shortened survival. Germ-free or antibiotic-treated mice transplanted with patient feces from responders had enhanced therapeutic responses to PD-1 blockade. Specific bacterial types comprised favorable microbiomes, so manipulating microbiota may provide another therapeutic approach to enhance cancer treatment.Routy B, …, Zitvogel L. Science 2017 Nov 2; DOI: 10.1126/science.aan3706.Gopalakrishnan V, …, Wargo JA. Science 2017 Nov 2; DOI: 10.1126/science.aan4236.Pancreatic tumor (from Shakya, Cancer Res 2012;73:885)Few patients with pancreatic cancer become long-term survivors. Potential T-cell responses that could be beneficial in long-term survivors were examined in depth. Tumors with high neoantigen loads and abundant CD8+ T-cell infiltrates were associated with the longest survival. Neoantigen quality, as defined by similarities to microbial peptides or with MUC16 neoepitopes, improved survival predictions. T cells to these antigens could be detected in tumors and in long-term survivors. The high-quality neoantigens were often lost upon metastatic progression, perhaps reflecting immune editing.Balachandran VP, …, Leach SD. Nature 2017 Nov 8. DOI: 10.1038/nature24462.Fatty liver (from Nephron via Wikimedia Commons)Patients with fatty-liver disease have more circulating IgA and a propensity to develop hepatocellular carcinoma (HCC). The IgA is likely produced by plasmocytes that can develop by TGFβ-mediated conversion from IgM- to IgA-expressing B cells, and which accumulate in the fibrotic liver. In animal models of nonalcoholic steatohepatitis, these IgA-producers express PD-L1 and suppress antitumor activity of CD8+ CTLs. Depletion of T cells accelerates the development of HCC, whereas ablation of IgA-producing cells reduces tumor development. Blockade of PD-L1 induces tumor regression presumably by targeting PD-L1+ plasmocytes, as the benefit was lost in mice lacking IgA+ cells.Shalapour S, …, Karin M. Nature 2017 Nov 8;551:340–5.CAFs in suppressive tumor environment (from Granot & Fridlender, Cancer Res 2015;75:4441)An unintended consequence of CSF1R blockade (which depletes tumor-associated macrophages) was an increase in myeloid-derived suppressor cells (PMN-MDSCs), thwarting any antitumor effects. CSF1 produced by tumor cells downregulated granulocyte-specific chemokine expression in cancer-associated fibroblasts, and treatment with CSF1R inhibitors disrupted this crosstalk, triggering increased recruitment of PMN-MDSCs. In a mouse tumor model, combining CSF1-R blockade with a CXCR2 antagonist blocked PMN-MDSC infiltration, resulting in potent antitumor effects.Kumar V, …, Gabrilovich DI. Cancer Cell 2017 Nov 13;32:654–68.e5.Transferring mobile information (by Tableatny via Flickr)Macrophages are often associated with tumor progression. In a human-in-zebrafish xenograft model of melanoma, M2 macrophages were recruited in a MyD88-dependent fashion and stayed in prolonged contact with tumor cells. Macrophages transferred cytoplasm to the tumor cells, which correlated with tumor cell dissemination. Cytoplasmic material presumably can be transferred from macrophages by multiple mechanisms, although the nature of the critical pathway(s) and active moieties being transferred are as yet unknown.Roh-Johnson M, …, Moens CB. Dev Cell 2017 Dec 4;43:549–62.e6.56yu7t.

Animal Models of Non-alcoholic Fatty Liver Diseases and Its Associated Liver Cancer.

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of diseases, which include simple liver steatosis, non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). It is a burgeoning health problem worldwide in line with the trend towards unhealthy diet and increased prevalence of obesity and type 2 diabetes mellitus (T2DM). Many animal models that illustrate both the histology and pathology of human NAFLD have been established. It is important to choose an animal model that best conforms to the aim of the study. This chapter presents a critical analysis of the histopathology and pathogenesis of NAFLD and the most commonly used and recently developed animal models of hepatic steatosis, NASH and NAFLD-induced hepatocellular carcinoma (NAFLD-HCC). The main mechanisms involved in the experimental pathogenesis of NAFLD in various animal models were also discussed. This chapter also includes a brief summary of recent therapeutic targets found using animal models. Although current animal models provide important guidance in understanding the pathogenesis and development of NAFLD, future study is essential to develop more precise models that better mimic the disease spectrum for both improved mechanistic understanding and identification of novel therapeutic options.

Pharmacological stimulation of p53 with low-dose doxorubicin ameliorates diet-induced nonalcoholic steatosis and steatohepatitis

ObjectiveRecent reports have implicated the p53 tumor suppressor in the regulation of lipid metabolism. We hypothesized that the pharmacological activation of p53 with low-dose doxorubicin, which is widely used to treat several types of cancer, may have beneficial effects on nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). MethodsWe used long-term pharmacological activation of p53 by i.p. or oral administration of low-dose doxorubicin in different animal models of NAFLD (high fat diet containing 45% and 60% kcal fat) and NASH (methionine- and choline-deficient diet and choline deficiency combined with high fat diet). We also administered doxorubicin in mice lacking p53 in the liver and in two human hepatic cells lines (HepG2 and THLE2). ResultsThe attenuation of liver damage was accompanied by the stimulation of fatty acid oxidation and decrease of lipogenesis, inflammation, and ER stress. The effects of doxorubicin were abrogated in mice with liver-specific ablation of p53. Finally, the effects of doxorubicin on lipid metabolism found in animal models were also present in two human hepatic cells lines, in which the drug stimulated fatty acid oxidation and inhibited de novo lipogenesis at doses that did not cause changes in apoptosis or cell viability. ConclusionThese data provide new evidence for targeting p53 as a strategy to treat liver disease.

Attenuating the rate of total body fat accumulation and alleviating liver damage by oral administration of vitamin D-enriched edible mushrooms in a diet-induced obesity murine model is mediated by an anti-inflammatory paradigm shift

BackgroundHypovitaminosis D is associated with many features of the metabolic syndrome, including non-alcoholic fatty liver disease. Vitamin D-enriched mushrooms extracts exert a synergistic anti-inflammatory effect. The aim of the present study is to determine the immunomodulatory effect of oral administration of vitamin D-enriched mushrooms extracts on high-fat diet (HFD) animal model of non-alcoholic steatohepatitis (NASH).MethodsC57BL/6 mice on HFD were orally administered with vitamin D supplement, Lentinula edodes (LE) mushrooms extract, or vitamin D-enriched mushrooms extract for 25 weeks. Mice were studied for the effect of the treatment on the immune system, liver functions and histology, insulin resistance and lipid profile.ResultsTreatment with vitamin D-enriched LE extracts was associated with significant attenuation of the rate of total body fat accumulation, along with a decrease in hepatic fat content as measured by an EchoMRI. Significant alleviation of liver damage manifested by a marked decrease in ALT, and AST serum levels (from 900 and 1021 U/L in the control group to 313 and 340; 294 and 292; and 366 and 321 U/L for ALT and AST, in Vit D, LE and LE + Vit D treated groups, respectively). A corresponding effect on hepatocyte ballooning were also noted. A significant decrease in serum triglycerides (from 103 to 75, 69 and 72 mg/dL), total cholesterol (from 267 to 160, 157 and 184 mg/dL), and LDL cholesterol (from 193 mg/dL to 133, 115 and 124 mg/dL) along with an increase in the HDL/LDL ratio, and improved glucose levels were documented. These beneficial effects were associated with a systemic immunomodulatory effect associated with an increased CD4/CD8 lymphocyte ratio (from 1.38 in the control group to 1.69, 1.71 and 1.63), and a pro- to an anti-inflammatory cytokine shift.ConclusionsOral administration of vitamin-D enriched mushrooms extracts exerts an immune modulatory hepato-protective effect in NASH model.

Oral Administration of CardioAid and Lunasin Alleviates Liver Damage in a High-Fat Diet Nonalcoholic Steatohepatitis Model

Background: Several of the drugs in development for treatment of nonalcoholic steatohepatitis (NASH) target liver fibrosis or have side effects that prohibit their long-term use in patients with mild to moderate disease. Lunasin is a soy-derived peptide with anti-inflammatory properties. ADM's CardioAid™ is a plant sterol extract that exerts cholesterol- and triacylglycerol-lowering effects. Aim: To determine the immunomodulatory effects of CardioAid and lunasin in a high-fat diet (HFD) animal model of NASH. Methods: C57BL/6 mice on an HFD were orally administered CardioAid or lunasin for 25 weeks. The effects on the immune system, liver function, insulin resistance and lipid profile were studied. Results: Treatment with CardioAid and lunasin was associated with a significant decrease in the CD4/CD8 ratio and an increase in CD4+CD25+ lymphocytes. A decrease in interleukin 1-alpha serum levels and an increase in transforming growth factor beta serum levels were noted. These were associated with alleviation of liver damage as indicated by a significant decrease in liver enzymes and improvement in the histological nonalcoholic fatty liver disease activity score (NAS). Decreases in both serum triglyceride and serum glucose levels were observed in treated mice. A decrease in total body fat measured by EchoMRI was also observed in treated mice. Conclusions: CardioAid and lunasin exerted hepatoprotective and glucose-protective effects in an HFD NASH model. These data and the high-safety profiles of CardioAid and Lunasin support their use in patients in the early stages of NASH to prevent deterioration due to the disease.

The Role of Growth Hormone and Insulin-Like Growth Factor-I in the Liver.

Adult growth hormone deficiency (GHD) is characterized by metabolic abnormalities associated with visceral obesity, impaired quality of life, and increased mortality. Patients with adult GHD show increased prevalence of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), and growth hormone (GH) replacement therapy has been shown to improve these conditions. It has also been demonstrated that a decrease in the GH insulin-like growth factor-I (IGF-I) axis is closely associated with the progression of general NAFLD, suggesting a physiological role of these hormones for the maintenance of the liver. NASH histologically demonstrates inflammation, necrosis, and fibrosis, in addition to steatosis (and is a serious disease because it can progress to liver cirrhosis and hepatocellular carcinoma in a subset of cases). While fibrosis determines the prognosis of the patient, efficacious treatment for fibrosis is crucial; however, it has not yet been established. Recent studies have clarified the essential roles of GH and IGF-I in the liver. GH profoundly reduces visceral fat, which plays an important role in the development of NAFLD. Furthermore, GH directly reduces lipogenesis in the hepatocytes. IGF-I induces cellular senescence and inactivates hepatic stellate cells, therefore ameliorating fibrosis. IGF-I treatment has been shown to improve animal models of NASH and cirrhosis, suggesting potential clinical applications of IGF-I in these conditions. In this review, I will focus on the important roles of GH and IGF-I in the liver, their underlying mechanisms, and their potential therapeutic applications.

FoxO3 increases miR-34a to cause palmitate-induced cholangiocyte lipoapoptosis

Nonalcoholic steatohepatitis (NASH) patients have elevated plasma saturated free fatty acid levels. These toxic fatty acids can induce liver cell death and our recent results demonstrated that the biliary epithelium may be susceptible to lipotoxicity. Here, we explored the molecular mechanisms of cholangiocyte lipoapoptosis in cell culture and in an animal model of NASH. Treatment of cholangiocytes with palmitate (PA) showed increased caspase 3/7 activity and increased levels of cleaved poly (ADP-ribose) polymerase and cleaved caspase 3, demonstrating cholangiocyte lipoapoptosis. Interestingly, treatment with PA significantly increased the levels of microRNA miR-34a, a pro-apoptotic microRNA known to be elevated in NASH. PA induction of miR-34a was abolished in cholangiocytes transduced with forkhead family of transcription factor class O (FoxO)3 shRNA, demonstrating that FoxO3 activation is upstream of miR-34a and suggesting that FoxO3 is a novel transcriptional regulator of miR-34a. Further, anti-miR-34a protected cholangiocytes from PA-induced lipoapoptosis. Direct and indirect targets of miR-34a, such as SIRT1, receptor tyrosine kinase (MET), Kruppel-like factor 4, fibroblast growth factor receptor (FGFR)1, and FGFR4, were all decreased in PA-treated cholangiocytes. SIRT1 and MET were partially rescued by a miR-34a antagonist. Cholangiocyte apoptosis and miR-34a were dramatically increased in the liver of mice with early histologic features of NASH. Our study provides evidence for the pro-apoptotic role of miR-34a in PA-induced cholangiocyte lipoapoptosis in culture and in the liver.