The cytochrome P450 epoxygenase pathway regulates the hepatic inflammatory response in fatty liver disease

Corn Peptides Alleviate Nonalcoholic Fatty Liver Fibrosis in Mice by Inhibiting NLRP3 Inflammasome Activation and Regulating Gut Microbiota

This study aimed to investigate the effects of corn gluten-derived soluble epoxide hydrolase (sEH) inhibitory peptides on nonalcoholic fatty liver fibrosis induced by a high-fat diet and carbon tetrachloride in mice. Mice treated with corn peptides at doses of 500 or 1000 mg/kg/d for 4 weeks exhibited reduced sEH activity in serum and liver, enhanced lipid metabolism, and decreased lipid accumulation and oxidative stress. Corn peptides effectively downregulated the mRNA levels of Pro-IL-1β, Pro-IL-18, NOD-like receptor protein 3 (NLRP3), ASC, Pro-caspase-1, Caspase-1, and GSDMD in the liver. This hepatoprotective effect of corn peptides by inhibiting NLRP3 inflammasome activation was further validated in H2O2-induced HepG2 cells. Moreover, corn peptides restored the composition of the gut microbiota and promoted short-chain fatty acid production. This study provides evidence that corn-derived sEH inhibitory peptides have hepatoprotective activity against nonalcoholic fatty liver fibrosis by suppressing NLRP3 inflammasome activation and modulating gut microbiota.

Suppression of hepatic ChREBP⍺-CYP2C50 axis-driven fatty acid oxidation sensitizes mice to diet-induced MASLD/MASH

OBJECTIVES

Compromised hepatic fatty acid oxidation (FAO) has been observed in human MASH patients and animal models of MASLD/MASH. It remains poorly understood how and when the hepatic FAO pathway is suppressed during the progression of MASLD towards MASH. Hepatic ChREBP⍺ is a classical lipogenic transcription factor that responds to the intake of dietary sugars.

METHODS

We examined its role in regulating hepatocyte fatty acid oxidation (FAO) and the impact of hepatic Chrebpa deficiency on sensitivity to diet-induced MASLD/MASH in mice.

RESULTS

We discovered that hepatocyte ChREBP⍺ is both necessary and sufficient to maintain FAO in a cell-autonomous manner independently of its DNA-binding activity. Supplementation of synthetic PPAR⍺/δ agonist is sufficient to restore FAO in Chrebp-/- primary mouse hepatocytes. Hepatic ChREBP⍺ was decreased in mouse models of diet-induced MAFSLD/MASH and in patients with MASH. Hepatocyte-specific Chrebp⍺ knockout impaired FAO, aggravated liver steatosis and inflammation, leading to early-onset fibrosis in response to diet-induced MASH. Conversely, liver overexpression of ChREBP⍺-WT or its non-lipogenic mutant enhanced FAO, reduced lipid deposition, and alleviated liver injury, inflammation, and fibrosis. RNA-seq analysis identified the CYP450 epoxygenase (CYP2C50) pathway of arachidonic acid metabolism as a novel target of ChREBP⍺. Over-expression of CYP2C50 partially restores hepatic FAO in primary hepatocytes with Chrebp⍺ deficiency and attenuates preexisting MASH in the livers of hepatocyte-specific Chrebp⍺-deleted mice.

CONCLUSIONS

Our findings support the protective role of hepatocyte ChREBPa against diet-induced MASLD/MASH in mouse models in part via promoting CYP2C50-driven FAO.

Hedan tablet ameliorated non-alcoholic steatohepatitis by moderating NF-κB and lipid metabolism-related pathways via regulating hepatic metabolites

Non-alcoholic steatohepatitis (NASH) is a severe form of fatty liver disease. If not treated, it can lead to liver damage, cirrhosis and even liver cancer. However, advances in treatment have remained relatively slow, and there is thus an urgent need to develop appropriate treatments. Hedan tablet (HDP) is used to treat metabolic syndrome. However, scientific understanding of the therapeutic effect of HDP on NASH remains limited. We used HDP to treat a methionine/choline-deficient diet-induced model of NASH in rats to elucidate the therapeutic effects of HDP on liver injury. In addition, we used untargeted metabolomics to investigate the effects of HDP on metabolites in liver of NASH rats, and further validated its effects on inflammation and lipid metabolism following screening for potential target pathways. HDP had considerable therapeutic, anti-oxidant, and anti-inflammatory effects on NASH. HDP could also alter the hepatic metabolites changed by NASH. Moreover, HDP considerable moderated NF-κB and lipid metabolism-related pathways. The present study found that HDP had remarkable therapeutic effects in NASH rats. The therapeutic efficacy of HDP in NASH mainly associated with regulation of NF-κB and lipid metabolism-related pathways via arachidonic acid metabolism, glycine-serine-threonine metabolism, as well as steroid hormone biosynthesis.

Lipidome Changes Associated with a Diet-Induced Reduction in Hepatic Fat among Adolescent Boys with Metabolic Dysfunction-Associated Steatotic Liver Disease

Little is known about lipid changes that occur in the setting of metabolic-dysfunction-associated steatotic liver disease (MASLD) regression. We previously reported improvements in hepatic steatosis, de novo lipogenesis (DNL), and metabolomic profiles associated with oxidative stress, inflammation, and selected lipid metabolism in 40 adolescent boys (11-16 y) with hepatic steatosis ≥5% (98% meeting the definition of MASLD). Participants were randomized to a low-free-sugar diet (LFSD) (n = 20) or usual diet (n = 20) for 8 weeks. Here, we employed untargeted/targeted lipidomics to examine lipid adaptations associated with the LFSD and improvement of hepatic steatosis. Our LC-MS/MS analysis revealed decreased triglycerides (TGs), diacylglycerols (DGs), cholesteryl esters (ChE), lysophosphatidylcholine (LPC), and phosphatidylcholine (PC) species with the diet intervention (p < 0.05). Network analysis demonstrated significantly lower levels of palmitate-enriched TG species post-intervention, mirroring the previously shown reduction in DNL in response to the LFSD. Targeted oxylipins analysis revealed a decrease in the abundance of 8-isoprostane and 14,15-DiHET and an increase in 8,9-DiHET (p < 0.05). Overall, we observed reductions in TGs, DGs, ChE, PC, and LPC species among participants in the LFSD group. These same lipids have been associated with MASLD progression; therefore, our findings may indicate normalization of key biological processes, including lipid metabolism, insulin resistance, and lipotoxicity. Additionally, our targeted oxylipins assay revealed novel changes in eicosanoids, suggesting improvements in oxidative stress. Future studies are needed to elucidate the mechanisms of these findings and prospects of these lipids as biomarkers of MASLD regression.

Transcriptomic signatures of progressive and regressive liver fibrosis and portal hypertension

Persistent liver injury triggers a fibrogenic program that causes pathologic remodeling of the hepatic microenvironment (i.e., liver fibrosis) and portal hypertension. The dynamics of gene regulation during liver disease progression and early regression remain understudied. Here, we generated hepatic transcriptome profiles in two well-established liver disease models at peak fibrosis and during spontaneous regression after the removal of the inducing agents. We linked the dynamics of key disease readouts, such as portal pressure, collagen area, and transaminase levels, to differentially expressed genes, enabling the identification of transcriptomic signatures of progressive vs. regressive liver fibrosis and portal hypertension. These candidate biomarkers (e.g., Tcf4, Mmp7, Trem2, Spp1, Scube1, Islr) were validated in RNA sequencing datasets of patients with cirrhosis and portal hypertension, and those cured from hepatitis C infection. Finally, deconvolution identified major cell types and suggested an association of macrophage and portal hepatocyte signatures with portal hypertension and fibrosis area.

In vitro and in vivo toxicity of thiolated and PEGylated organosilica nanoparticles

This study comprises the comprehensive toxicological assessment of thiolated organosilica nanoparticles (NPs) synthesised from 3-mercaptopropyltrimethoxysilane (MPTS). We investigated the influence of three different types of nanoparticles synthesised from 3-mercaptopropyltrimethoxysilane: the starting thiolated silica (Si-NP-SH) and their derivatives prepared by surface PEGylation with PEG 750 (Si-NP-PEG750) and 5000 Da (Si-NP-PEG5000) on biological subjects from in vitro to in vivo experiments to explore the possible applications of those nanoparticles in biomedical research. As a result of this study, we generated a comprehensive understanding of the toxicological properties of these nanoparticles, including their cytotoxicity in different cell lines, hemolytic properties, in vitro localisation, mucosal irritation properties and biodistribution in BALB/c mice. Our findings indicate that all three types of nanoparticles can be considered safe and have promising prospects for use in biomedical applications. Nanoparticles did not affect the viability of HPF, MCF7, HEK293 and A549 cell lines at low concentrations (up to 100 µg/mL); moreover, they did not cause organ damage to BALB/c mice at concentrations of 10 mg/kg. The outcomes of this study enhance our understanding of the impact of organosilica nanoparticles on health and the environment, which is vital for developing silica nanoparticle-based drug delivery systems and provides opportunities to expand the applications of organosilica nanoparticles.

DEAD-Box Helicase 17 exacerbates non-alcoholic steatohepatitis via transcriptional repression of cyp2c29, inducing hepatic lipid metabolism disorder and eliciting the activation of M1 macrophages

OBJECTIVE

Our study was to elucidate the role of RNA helicase DEAD-Box Helicase 17 (DDX17) in NAFLD and to explore its underlying mechanisms.

METHODS

We created hepatocyte-specific Ddx17-deficient mice aim to investigate the impact of Ddx17 on NAFLD induced by a high-fat diet (HFD) as well as methionine and choline-deficient l-amino acid diet (MCD) in adult male mice. RNA-seq and lipidomic analyses were conducted to depict the metabolic landscape, and CUT&Tag combined with chromatin immunoprecipitation (ChIP) and luciferase reporter assays were conducted.

RESULTS

In this work, we observed a notable increase in DDX17 expression in the livers of patients with NASH and in murine models of NASH induced by HFD or MCD. After introducing lentiviruses into hepatocyte L02 for DDX17 knockdown or overexpression, we found that lipid accumulation induced by palmitic acid/oleic acid (PAOA) in L02 cells was noticeably weakened by DDX17 knockdown but augmented by DDX17 overexpression. Furthermore, hepatocyte-specific DDX17 knockout significantly alleviated hepatic steatosis, inflammatory response and fibrosis in mice after the administration of MCD and HFD. Mechanistically, our analysis of RNA-seq and CUT&Tag results combined with ChIP and luciferase reporter assays indicated that DDX17 transcriptionally represses Cyp2c29 gene expression by cooperating with CCCTC binding factor (CTCF) and DEAD-Box Helicase 5 (DDX5). Using absolute quantitative lipidomics analysis, we identified a hepatocyte-specific DDX17 deficiency that decreased lipid accumulation and altered lipid composition in the livers of mice after MCD administration. Based on the RNA-seq analysis, our findings suggest that DDX17 could potentially have an impact on the modulation of lipid metabolism and the activation of M1 macrophages in murine NASH models.

CONCLUSION

These results imply that DDX17 is involved in NASH development by promoting lipid accumulation in hepatocytes, inducing the activation of M1 macrophages, subsequent inflammatory responses and fibrosis through the transcriptional repression of Cyp2c29 in mice. Therefore, DDX17 holds promise as a potential drug target for the treatment of NASH.

Transcriptomics and Metabolomics Reveal Tomato Consumption Alters Hepatic Xenobiotic Metabolism and Induces Steroidal Alkaloid Metabolite Accumulation in Mice

SCOPE

Tomato consumption is associated with many health benefits including lowered risk for developing certain cancers. It is hypothesized that tomato phytochemicals are transported to the liver and other tissues where they alter gene expression in ways that lead to favorable health outcomes. However, the effects of tomato consumption on mammalian liver gene expression and chemical profile are not well defined.

METHODS AND RESULTS

The study hypothesizes that tomato consumption would alter mouse liver transcriptomes and metabolomes compared to a control diet. C57BL/6J mice (n = 11-12/group) are fed a macronutrient matched diet containing either 10% red tomato, 10% tangerine tomato, or no tomato powder for 6 weeks after weaning. RNA-Seq followed by gene set enrichment analyses indicates that tomato type and consumption, in general, altered expression of phase I and II xenobiotic metabolism genes. Untargeted metabolomics experiments reveal distinct clustering between control and tomato fed animals. Nineteen molecular formulas (representing 75 chemical features) are identified or tentatively identified as steroidal alkaloids and isomers of their phase I and II metabolites; many of which are reported for the first time in mammals.

CONCLUSION

These data together suggest tomato consumption may impart benefits partly through enhancing detoxification potential.

Increased Perfluorooctanesulfonate (PFOS) Toxicity and Accumulation Is Associated with Perturbed Prostaglandin Metabolism and Increased Organic Anion Transport Protein (OATP) Expression

Perfluorooctanesulfonate (PFOS) is a widespread environmental pollutant with a long half-life and clearly negative outcomes on metabolic diseases such as fatty liver disease and diabetes. Male and female Cyp2b-null and humanized CYP2B6-transgenic (hCYP2B6-Tg) mice were treated with 0, 1, or 10 mg/kg/day PFOS for 21 days, and surprisingly it was found that PFOS was retained at greater concentrations in the serum and liver of hCYP2B6-Tg mice than those of Cyp2b-null mice, with greater differences in the females. Thus, Cyp2b-null and hCYP2B6-Tg mice provide new models for investigating individual mechanisms for PFOS bioaccumulation and toxicity. Overt toxicity was greater in hCYP2B6-Tg mice (especially females) as measured by mortality; however, steatosis occurred more readily in Cyp2b-null mice despite the lower PFOS liver concentrations. Targeted lipidomics and transcriptomics from PFOS-treated Cyp2b-null and hCYP2B6-Tg mouse livers were performed and compared to PFOS retention and serum markers of toxicity using PCA. Several oxylipins, including prostaglandins, thromboxanes, and docosahexaenoic acid metabolites, are associated or inversely associated with PFOS toxicity. Both lipidomics and transcriptomics indicate PFOS toxicity is associated with PPAR activity in all models. GO terms associated with reduced steatosis were sexually dimorphic with lipid metabolism and transport increased in females and circadian rhythm associated genes increased in males. However, we cannot rule out that steatosis was initially protective from PFOS toxicity. Moreover, several transporters are associated with increased retention, probably due to increased uptake. The strongest associations are the organic anion transport proteins (Oatp1a4-6) genes and a long-chain fatty acid transport protein (fatp1), enriched in female hCYP2B6-Tg mice. PFOS uptake was also reduced in cultured murine hepatocytes by OATP inhibitors. The role of OATP1A6 and FATP1 in PFOS transport has not been tested. In summary, Cyp2b-null and hCYP2B6-Tg mice provided unique models for estimating the importance of novel mechanisms in PFOS retention and toxicity.

Transcriptomic profiling of long non-coding RNAs and messenger RNAs in the liver of mice during Toxoplasma gondii infection

BACKGROUND

Toxoplasma gondii is an intracellular protozoan parasite that can infect a wide range of warm-blooded animals, including humans. It poses significant health risks, particularly in immunocompromised individuals and during pregnancy, leading to severe disease manifestations. The liver, being a crucial organ involved in immune response and metabolic regulation, plays a critical role in the host's defense against T. gondii infection.

METHODS

In this study, we utilized RNA sequencing to investigate the expression profiles of long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in the liver of mice infected with T. gondii. By employing this method, we obtained a comprehensive overview of the alterations in gene expression occurring in the liver during infection.

RESULTS

By comparing the infected groups to the control groups, we identified numerous differentially expressed lncRNAs DElncRNAs and DEmRNAs at two stages of infection. Specifically, at the acute infection stage, we found 628 DElncRNAs, and 6346 DEmRNAs. At the chronic infection stage, we identified 385 DElncRNAs and 2513 DEmRNAs. Furthermore, we identified 1959 commonly expressed DEmRNAs, including IL27, Nos2, and Cxcr2, across two infection stages. Enrichment and co-location analyses revealed pathways linked to immune and inflammatory responses during T. gondii infection. Notably, through co-location analysis, our analysis revealed several DElncRNAs, including Gm29156, Gm29157, and Gm28644, which are potentially implicated in the progression of liver inflammation induced by T. gondii. Additionally, functional enrichment analysis disclosed stage-specific characteristics of liver inflammation and immune response, alongside changes in metabolic regulation and immunosuppression pathways.

CONCLUSIONS

Our findings provide valuable insights into the expression patterns of lncRNAs and mRNAs in the liver at different stages of T. gondii infection. We identified potential regulatory factors and pathways implicated in liver inflammation, thereby enhancing our understanding of the molecular mechanisms underlying liver inflammation and immune responses during T. gondii infection. These findings could contribute to the development of targeted therapeutic strategies for liver inflammation in the context of T. gondii infection.

Bioactive signalling lipids as drivers of chronic liver diseases

Lipids are important in multiple cellular functions, with most having structural or energy storage roles. However, a small fraction of lipids exert bioactive roles through binding to G protein-coupled receptors and induce a plethora of processes including cell proliferation, differentiation, growth, migration, apoptosis, senescence and survival. Bioactive signalling lipids are potent modulators of metabolism and energy homeostasis, inflammation, tissue repair and malignant transformation. All these events are involved in the initiation and progression of chronic liver diseases. In this review, we focus specifically on the roles of bioactive lipids derived from phospholipids (lyso-phospholipids) and poly-unsaturated fatty acids (eicosanoids, pro-resolving lipid mediators and endocannabinoids) in prevalent chronic liver diseases (alcohol-associated liver disease, non-alcoholic fatty liver disease, viral hepatitis and hepatocellular carcinoma). We discuss the balance between pathogenic and beneficial bioactive lipids as well as potential therapeutic targets related to the agonism or antagonism of their receptors.

Hepatocellular loss of mTOR aggravates tumor burden in nonalcoholic steatohepatitis-related HCC

Obesity and associated nonalcoholic steatohepatitis (NASH) are on the rise globally. NASH became an important driver of hepatocellular carcinoma (HCC) in recent years. Activation of the central metabolic regulator mTOR (mechanistic target of rapamycin) is frequently observed in HCCs. However, mTOR inhibition failed to improve the outcome of HCC therapies, demonstrating the need for a better understanding of the molecular and functional consequences of mTOR blockade. We established a murine NASH-driven HCC model based on long-term western diet feeding combined with hepatocellular mTOR-inactivation. We evaluated tumor load and whole-body fat percentage via µCT-scans, analyzed metabolic blood parameters and tissue proteome profiles. Additionally, we used a bioinformatic model to access liver and HCC mitochondrial metabolic functions. The tumor burden was massively increased via mTOR-knockout. Several signs argue for extensive metabolic reprogramming of glucose, fatty acid, bile acid and cholesterol metabolism. Kinetic modeling revealed reduced oxygen consumption in KO-tumors. NASH-derived HCC pathogenesis is driven by metabolic disturbances and should be considered separately from those caused by other etiologies. We conclude that mTOR functions as tumor suppressor in hepatocytes especially under long-term western diet feeding. However, some of the detrimental consequences of this diet are attenuated by mTOR blockade.

Time course of western diet (WD) induced nonalcoholic steatohepatitis (NASH) in female and male Ldlr-/- mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a global health problem. Identification of factors contributing to the onset and progression of NAFLD have the potential to direct novel strategies to combat NAFLD.

METHODS

We examined the time course of western diet (WD)-induced NAFLD and its progression to nonalcoholic steatohepatitis (NASH) in age-matched female and male Ldlr-/- mice, with time-points at 1, 4, 8, 20 and 40 weeks on the WD. Controls included Ldlr-/- mice maintained on a purified low-fat diet (LFD) for 1 and 40 weeks. The approach included quantitation of anthropometric, plasma and liver markers of disease, plus hepatic histology, lipids, oxylipins, gene expression and selected metabolites.

RESULTS

One week of feeding the WD caused a significant reduction in hepatic essential fatty acids (EFAs: 18:2, ω6, 18:3, ω3) which preceded the decline in many C20-22 ω3 and ω6 polyunsaturated fatty acids (PUFA) and PUFA-derived oxylipins after 4 weeks on the WD. In addition, expression of hepatic inflammation markers (CD40, CD44, Mcp1, Nlrp3, TLR2, TLR4, Trem2) increased significantly in both female & male mice after one week on the WD. These markers continued to increase over the 40-week WD feeding study. WD effects on hepatic EFA and inflammation preceded all significant WD-induced changes in body weight, insulin resistance (HOMA-IR), oxidative stress status (GSH/GSSG ratio) and histological and gene expression markers of macrosteatosis, extracellular matrix remodeling and fibrosis.

CONCLUSIONS

Our findings establish that feeding Ldlr-/- mice the WD rapidly lowered hepatic EFAs and induced key inflammatory markers linked to NASH. Since EFAs have an established role in inflammation and hepatic inflammation plays a major role in NASH, we suggest that early clinical assessment of EFA status and correcting EFA deficiencies may be useful in reducing NASH severity.

Nonalcoholic Fatty Liver Disease and Omega-3 Fatty Acids: Mechanisms and Clinical Use

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic fatty liver disease worldwide, particularly in obese and type 2 diabetic individuals. Currently, there are no therapies for NAFLD that have been approved by the US Food and Drug Administration. Herein, we examine the rationale for using ω3 polyunsaturated fatty acids (PUFAs) in NAFLD therapy. This focus is based on the finding that NAFLD severity is associated with a reduction of hepatic C20-22 ω3 PUFAs. Because C20-22 ω3 PUFAs are pleiotropic regulators of cell function, loss of C20-22 ω3 PUFAs has the potential to significantly impact hepatic function. We describe NAFLD prevalence and pathophysiology as well as current NAFLD therapies. We also present evidence from clinical and preclinical studies that evaluated the capacity of C20-22 ω3 PUFAs to treat NAFLD. Given the clinical and preclinical evidence, dietary C20-22 ω3 PUFA supplementation has the potential to decrease human NAFLD severity by reducing hepatosteatosis and liver injury.

Lipidomics in pathogenesis, progression and treatment of nonalcoholic steatohepatitis (NASH): Recent advances

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease affecting up to 30% of the general adult population. NAFLD encompasses a histological spectrum ranging from pure steatosis to non-alcoholic steatohepatitis (NASH). NASH can progress to cirrhosis and is becoming the most common indication for liver transplantation, as a result of increasing disease prevalence and of the absence of approved treatments. Lipidomic readouts of liver blood and urine samples from experimental models and from NASH patients disclosed an abnormal lipid composition and metabolism. Collectively, these changes impair organelle function and promote cell damage, necro-inflammation and fibrosis, a condition termed lipotoxicity. We will discuss the lipid species and metabolic pathways leading to NASH development and progression to cirrhosis, as well as and those species that can contribute to inflammation resolution and fibrosis regression. We will also focus on emerging lipid-based therapeutic opportunities, including specialized proresolving lipid molecules and macrovesicles contributing to cell-to-cell communication and NASH pathophysiology.

Detoxification Cytochrome P450s (CYPs) in Families 1-3 Produce Functional Oxylipins from Polyunsaturated Fatty Acids

This manuscript reviews the CYP-mediated production of oxylipins and the current known function of these diverse set of oxylipins with emphasis on the detoxification CYPs in families 1-3. Our knowledge of oxylipin function has greatly increased over the past 3-7 years with new theories on stability and function. This includes a significant amount of new information on oxylipins produced from linoleic acid (LA) and the omega-3 PUFA-derived oxylipins such as α-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). However, there is still a lack of knowledge regarding the primary CYP responsible for producing specific oxylipins, and a lack of mechanistic insight for some clinical associations between outcomes and oxylipin levels. In addition, the role of CYPs in the production of oxylipins as signaling molecules for obesity, energy utilization, and development have increased greatly with potential interactions between diet, endocrinology, and pharmacology/toxicology due to nuclear receptor mediated CYP induction, CYP inhibition, and receptor interactions/crosstalk. The potential for diet-diet and diet-drug/chemical interactions is high given that these promiscuous CYPs metabolize a plethora of different endogenous and exogenous chemicals.

Metabolomics- and systems toxicology-based hepatotoxicity mechanism of Sophorae Tonkinensis Radix et Rhizoma in rats

Drug-induced liver injury (DILI) is a major challenge to the development and clinical application of drugs, especially limits the global application of Chinese herbal medicines, because the material basis and mechanisms of some Chinese herbal medicines are not well clear. In this study, a comprehensive method integrating metabolomics and systems toxicology (SysT) was used to investigate how the main substances in Sophorae TonkinensisRadix et Rhizoma (STRER) influence the metabolic pathways and molecular mechanisms of hepatotoxicity. Through a 28-day continuous oral administration toxicity study combined with serum metabolomics analyses, the aqueous, ethanol-precipitation and dichloromethane extracts of STRER exhibited significant hepatotoxic effects. In addition, 19 differential metabolites with a time-dose-effect relationship were identified in rats. The primary bile acid biosynthesis pathway was significantly altered, which was consistent with the findings of the SysT analysis. Furthermore, through the quantification of bile acids in serum, 16 differential bile acids were identified as being significantly changed; moreover, 21 relevant targets which intersected with the hepatotoxic targets of STRER were identified. Molecular docking was used to confirm the validation of bindings between targets and corresponding compounds, and finally, six important compounds and 14 potential targets were identified to be involved in STRER-induced liver injury in relation to bile acid metabolism.

Familial hemophagocytic lymphohistiocytosis hepatitis is mediated by IFN-γ in a predominantly hepatic-intrinsic manner

Interferon gamma (IFN-γ) is the main cytokine driving organ dysfunction in Familial Hemophagocytic Lymphohistiocytosis (FHL). Blockade of IFN-γ pathway ameliorates FHL hepatitis, both in animal models and in humans with FHL. Hepatocytes are known to express IFN-γ receptor (IFN-γ-R). However, whether IFN-γ induced hepatitis in FHL is a lymphocyte or liver intrinsic response to the cytokine has yet to be elucidated. Using a IFNgR-/- bone marrow chimeric model, this study showed that non-hematopoietic IFN-γ response is critical for development of FHL hepatitis in LCMV-infected Prf1-/- mice. Lack of hepatic IFN-γ responsiveness results in reduced hepatitis as measured by hepatomegaly, alanine aminotransferase (ALT) levels and abrogated histologic endothelial inflammation. In addition, IFN-γ non-hematopoietic response was critical in activation of lymphocytes by soluble interleukin 2 receptor (sIL-2r) and recruitment of CD8+ effector T lymphocytes (CD8+ CD44hi CD62Llo) (Teff) and inflammatory monocytes. Lastly, non-hematopoietic IFN-γ response results in increased hepatic transcription of type 1 immune response and oxidative stress response pathways, while decreasing transcription of genes involved in extracellular matrix (ECM) production. In summary, these findings demonstrate that there is a hepatic transcriptional response to IFN-γ, likely critical in the pathogenesis of FHL hepatitis and hepatic specific responses could be a therapeutic target in this disorder.

Genetic loci and metabolic states associated with murine epigenetic aging

Changes in DNA methylation (DNAm) are linked to aging. Here, we profile highly conserved CpGs in 339 predominantly female mice belonging to the BXD family for which we have deep longevity and genomic data. We use a 'pan-mammalian' microarray that provides a common platform for assaying the methylome across mammalian clades. We computed epigenetic clocks and tested associations with DNAm entropy, diet, weight, metabolic traits, and genetic variation. We describe the multifactorial variance of methylation at these CpGs and show that high-fat diet augments the age-related changes. Entropy increases with age. The progression to disorder, particularly at CpGs that gain methylation over time, was predictive of genotype-dependent life expectancy. The longer-lived BXD strains had comparatively lower entropy at a given age. We identified two genetic loci that modulate epigenetic age acceleration (EAA): one on chromosome (Chr) 11 that encompasses the Erbb2/Her2 oncogenic region, and the other on Chr19 that contains a cytochrome P450 cluster. Both loci harbor genes associated with EAA in humans, including STXBP4, NKX2-3, and CUTC. Transcriptome and proteome analyses revealed correlations with oxidation-reduction, metabolic, and immune response pathways. Our results highlight concordant loci for EAA in humans and mice, and demonstrate a tight coupling between the metabolic state and epigenetic aging.

The Beneficial Additive Effect of Silymarin in Metformin Therapy of Liver Steatosis in a Pre-Diabetic Model

The combination of plant-derived compounds with anti-diabetic agents to manage hepatic steatosis closely associated with diabetes mellitus may be a new therapeutic approach. Silymarin, a complex of bioactive substances extracted from Silybum marianum, evinces an antioxidative, anti-inflammatory, and hepatoprotective activity. In this study, we investigated whether metformin (300 mg/kg/day for four weeks) supplemented with micronized silymarin (600 mg/kg/day) would be effective in mitigating fatty liver disturbances in a pre-diabetic model with dyslipidemia. Compared with metformin monotherapy, the metformin-silymarin combination reduced the content of neutral lipids (TAGs) and lipotoxic intermediates (DAGs). Hepatic gene expression of enzymes and transcription factors involved in lipogenesis (Scd-1, Srebp1, Pparγ, and Nr1h) and fatty acid oxidation (Pparα) were positively affected, with hepatic lipid accumulation reducing as a result. Combination therapy also positively influenced arachidonic acid metabolism, including its metabolites (14,15-EET and 20-HETE), mitigating inflammation and oxidative stress. Changes in the gene expression of cytochrome P450 enzymes, particularly Cyp4A, can improve hepatic lipid metabolism and moderate inflammation. All these effects play a significant role in ameliorating insulin resistance, a principal background of liver steatosis closely linked to T2DM. The additive effect of silymarin in metformin therapy can mitigate fatty liver development in the pre-diabetic state and before the onset of diabetes.

Development and in vitro Profiling of Dual FXR/LTA4H Modulators

Designed polypharmacology presents as an attractive strategy to increase therapeutic efficacy in multi-factorial diseases by a directed modulation of multiple involved targets with a single molecule. Such an approach appears particularly suitable in non-alcoholic steatohepatitis (NASH) which involves hepatic steatosis, inflammation and fibrosis as pathological hallmarks. Among various potential pharmacodynamic mechanisms, activation of the farnesoid X receptor (FXRa) and inhibition of leukotriene A4 hydrolase (LTA4Hi) hold promise to counteract NASH according to preclinical and clinical observations. We have developed dual FXR/LTA4H modulators as pharmacological tools, enabling evaluation of this polypharmacology concept to treat NASH and related pathologies. The optimized FXRa/LTA4Hi exhibits well-balanced dual activity on the intended targets with sub-micromolar potency and is highly selective over related nuclear receptors and enzymes rendering it suitable as tool to probe synergies of dual FXR/LTA4H targeting.

Oxylipin Responses to Fasting and Insulin Infusion in a Large Mammalian Model of Fasting-Induced Insulin Resistance, the Northern Elephant Seal

The prolonged, post-weaning fast of northern elephant seal (Mirounga angustirostris) pups is characterized by a reliance on lipid metabolism and reversible, fasting-induced insulin resistance providing a unique model to examine the effects of insulin on lipid metabolism. We have previously shown that acute insulin infusion induced a shift in fatty acid metabolism dependent on fasting duration. This study complements the previous study by examining the effects of fasting duration and insulin infusion on circulating levels of oxylipins, bioactive metabolites derived from the oxygenation of polyunsaturated fatty acids. Northern elephant seal pups were studied at two post-weaning periods (n = 5/period): early fasting (1-2 weeks post-weaning; 127 ± 1 kg) and late fasting (6-7 weeks post-weaning; 93 ± 4 kg). Different cohorts of pups were weighed, sedated, and infused with 65 mU/kg of insulin. Plasma was collected prior to infusion (T0), and at 10, 30, 60, and 120 min post-infusion. A profile of ~80 oxylipins were analyzed by UPLC-ESI-MS/MS. Nine oxylipins changed between early and late fasting and eight were altered in response to insulin infusion. Fasting decreased PGF2a and increased 14,15-DiHETrE, 20-HETE, and 4-HDoHE (p<0.03) in T0 samples, while insulin infusion resulted in an inverse change in area under the curve (AUC) levels in these same metabolites (p<0.05). In addition, 12-HpETE and 12-HETE decreased with fasting and insulin infusion, respectively (p<0.04). The oxylipins altered during fasting and in response to insulin infusion may contribute to the manifestation of insulin resistance and participate in the metabolic regulation of associated cellular processes.

Second-Generation Dual FXR/sEH Modulators with Optimized Pharmacokinetics

Non-alcoholic steatohepatitis (NASH) presents as an epidemic chronic liver disease that is closely associated with metabolic disorders and involves hepatic steatosis, inflammation, and fibrosis as key factors. Despite the enormous global prevalence of NASH, effective pharmacological interventions are lacking. Based on the hypothesis that the multifactorial condition NASH may benefit from combined multiple modes of action for enhanced therapeutic efficacy, we have previously developed dual FXR activators/sEH inhibitors (FXRa/sEHi) and observed remarkable antifibrotic effects upon their use in rodent NASH models. However, these first-generation FXRa/sEHi were characterized by moderate metabolic stability and short in vivo half-life. Aiming to overcome these pharmacokinetic drawbacks, we have systematically studied the structure-activity and structure-stability relationships of the chemotype and obtained second-generation FXRa/sEHi with improved pharmacokinetic parameters. With high plasma exposure, a half-life greater than 5 h, and similar dual potency on the intended targets, 13 presents as a substantially optimized FXRa/sEHi for late-stage preclinical development.

Targeting the eicosanoid pathway in hepatocellular carcinoma

Liver cancer has variable incidence worldwide and high mortality. Histologically, the most common subtype of liver cancer is hepatocellular carcinoma (HCC). Approximately 30-40% of HCC patients are diagnosed at an advanced stage, and at present, there are limited treatment options for such patients. The current first-line therapy with tyrosine kinase inhibitors, sorafenib or lenvatinib, prolongs survival by a median of about 2.5-3 months after which the disease normally progresses. Additionally, many patients discontinue the use of tyrosine kinase inhibitors due to toxicity or may not be suitable candidates due to co-morbidity or frailty. It is, therefore, imperative to identify novel therapeutic targets for advanced HCC patients. Persistent injury to the liver as a result of insults such as hepatitis B or C viral (HBV or HCV) infections, alcohol abuse, and non-alcoholic fatty liver disease (NAFLD), results in chronic inflammation, which progresses to hepatic fibrosis and later, cirrhosis, provides the conditions for initiation of HCC. One of the key pathways studied for its role in inflammation and carcinogenesis is the eicosanoid pathway. In this review, we briefly outline the eicosanoid pathway, describe the mechanisms by which some pathway members either facilitate or counter the development of liver diseases, with the focus on NAFLD/hepatic fibrosis/cirrhosis, and HCC. We describe the link between the eicosanoid pathway, inflammation and these liver diseases, and identify components of the eicosanoid pathway that may be used as potential therapeutic targets in HCC.

Multi-Target Approaches in Metabolic Syndrome

Metabolic syndrome (MetS) is a highly prevalent disease cluster worldwide. It requires polypharmacological treatment of the single conditions including type II diabetes, hypertension, and dyslipidemia, as well as the associated comorbidities. The complex treatment regimens with various drugs lead to drug-drug interactions and inadequate patient adherence, resulting in poor management of the disease. Multi-target approaches aim at reducing the polypharmacology and improving the efficacy. This review summarizes the medicinal chemistry efforts to develop multi-target ligands for MetS. Different combinations of pharmacological targets in context of in vivo efficacy and future perspective for multi-target drugs in MetS are discussed.

Impact of liver-specific GLUT8 silencing on fructose-induced inflammation and omega oxidation

Excessive consumption of high-fructose diets is associated with insulin resistance, obesity, and non-alcoholic fatty liver disease (NAFLD). However, fructose differentially affects hepatic regulation of lipogenesis in males and females. Hence, additional studies are necessary in order to find strategies taking gender disparities in fructose-induced liver damage into consideration. Although the eighth member of facilitated glucose transporters (GLUT8) has been linked to fructose-induced macrosteatosis in female mice, its contribution to the inflammatory state of NAFLD remains to be elucidated. Combining pharmacological, biochemical, and proteomic approaches, we evaluated the preventive effect of targeted liver GLUT8 silencing on liver injury in a mice female fructose-induced non-alcoholic steatohepatitis female mouse model. Liver GLUT8-knockdown attenuated fructose-induced ER stress, recovered liver inflammation, and dramatically reduced fatty acid content, in part, via the omega oxidation. Therefore, this study links GLUT8 with liver inflammatory response and suggests GLUT8 as a potential target for the prevention of NAFLD.

Regulation of the cytochrome P450 epoxyeicosanoid pathway is associated with distinct histologic features in pediatric non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a significant health burden in obese children for which there is currently no specific therapy. Preclinical studies indicate that epoxyeicosanoids, a class of bioactive lipid mediators that are generated by cytochrome P450 (CYP) epoxygenases and inactivated by the soluble epoxide hydrolase (sEH), play a protective role in NAFLD. We performed a comprehensive lipidomics analysis using liver tissue and blood samples of 40 children with NAFLD. Proteomics was performed to determine CYP epoxygenase and sEH expressions. Hepatic epoxyeicosanoids significantly increased with higher grades of steatosis, while their precursor PUFAs were unaltered. Concomitantly, total CYP epoxygenase activity increased while protein level and activity of sEH decreased. In contrast, hepatic epoxyeicosanoids showed a strong decreasing trend with higher stages of fibrosis, accompanied by a decrease of CYP epoxygenase activity and protein expression. These findings suggest that the CYP epoxygenase/sEH pathway represents a potential pharmacologic target for the treatment of NAFLD.

Soluble epoxide hydrolase as a therapeutic target for obesity-induced disorders: roles of gut barrier function involved

Emerging research supports that soluble epoxide hydrolase (sEH), an enzyme involved in eicosanoid metabolism, could be a promising target for obesity-associated disorders. The sEH enzyme is overexpressed in many tissues of obese animals. Genetic ablation or pharmacological inhibition of sEH attenuates the development of a wide range of obesity-induced disorders, including endoplasmic reticulum stress, metabolic syndrome, kidney diseases, insulin resistance, fatty liver, hepatic steatosis, inflammation, and endothelial dysfunction. Furthermore, our recent research showed that genetic ablation or inhibition of sEH attenuated obesity-induced intestinal barrier dysfunction and its resulted bacterial translocation, which is widely regarded to be a central mechanism for the pathogenesis of various obesity-induced disorders. Together, these results support that targeting sEH could be a promising strategy to reduce risks of obesity-induced disorders, at least in part through blocking obesity-induced leaky gut syndrome.

Involvement of cytochrome P450 enzymes in inflammation and cancer: a review

Cytochrome P450 (CYP) enzymes are responsible for the biotransformation of drugs, xenobiotics, and endogenous substances. This enzymatic activity can be modulated by intrinsic and extrinsic factors, modifying the organism's response to medications. Among the factors that are responsible for enzyme inhibition or induction is the release of proinflammatory cytokines, such as interleukin-1 (IL-1), IL-6, tumor necrosis factor α (TNF-α), and interferon-γ (IFN-γ), from macrophages, lymphocytes, and neutrophils. These cells are also present in the tumor microenvironment, participating in the development of cancer, a disease that is characterized by cellular mutations that favor cell survival and proliferation. Mutations also occur in CYP enzymes, resulting in enzymatic polymorphisms and modulation of their activity. Therefore, the inhibition or induction of CYP enzymes by proinflammatory cytokines in the tumor microenvironment can promote carcinogenesis and affect chemotherapy, resulting in adverse effects, toxicity, or therapeutic failure. This review discusses the relevance of CYPs in hepatocarcinoma, breast cancer, lung cancer, and chemotherapy by reviewing in vitro, in vivo, and clinical studies. We also discuss the importance of elucidating the relationships between inflammation, CYPs, and cancer to predict drug interactions and therapeutic efficacy.

Soluble Epoxide Hydrolase Hepatic Deficiency Ameliorates Alcohol-Associated Liver Disease

BACKGROUND & AIMS

Alcohol-associated liver disease (ALD) is a significant cause of liver-related morbidity and mortality worldwide and with limited therapies. Soluble epoxide hydrolase (sEH; Ephx2) is a largely cytosolic enzyme that is highly expressed in the liver and is implicated in hepatic function, but its role in ALD is mostly unexplored.

METHODS

To decipher the role of hepatic sEH in ALD, we generated mice with liver-specific sEH disruption (Alb-Cre; Ephx2^fl/fl). Alb-Cre; Ephx2^fl/fl and control (Ephx2^fl/fl) mice were subjected to an ethanol challenge using the chronic plus binge model of ALD and hepatic injury, inflammation, and steatosis were evaluated under pair-fed and ethanol-fed states. In addition, we investigated the capacity of pharmacologic inhibition of sEH in the chronic plus binge mouse model.

RESULTS

We observed an increase of hepatic sEH in mice upon ethanol consumption, suggesting that dysregulated hepatic sEH expression might be involved in ALD. Alb-Cre; Ephx2^fl/fl mice presented efficient deletion of hepatic sEH with corresponding attenuation in sEH activity and alteration in the lipid epoxide/diol ratio. Consistently, hepatic sEH deficiency ameliorated ethanol-induced hepatic injury, inflammation, and steatosis. In addition, targeted metabolomics identified lipid mediators that were impacted significantly by hepatic sEH deficiency. Moreover, hepatic sEH deficiency was associated with a significant attenuation of ethanol-induced hepatic endoplasmic reticulum and oxidative stress. Notably, pharmacologic inhibition of sEH recapitulated the effects of hepatic sEH deficiency and abrogated injury, inflammation, and steatosis caused by ethanol feeding.

CONCLUSIONS

These findings elucidated a role for sEH in ALD and validated a pharmacologic inhibitor of this enzyme in a preclinical mouse model as a potential therapeutic approach.

Targeting n-3 Polyunsaturated Fatty Acids in Non-Alcoholic Fatty Liver Disease

BACKGROUND

Non-Alcoholic Fatty Liver Disease (NAFLD) is characterized by abnormal hepatic accumulation of triacylglycerides in the absence of alcohol consumption, in association with Oxidative Stress (OS), a pro-inflammatory state and Insulin Resistance (IR), which are attenuated by n-3 long-chain polyunsaturated Fatty Acids (FAs) C20-C22 (LCPUFAs) supplementation. Main causes of NAFLD comprise high caloric intake and a sedentary lifestyle, with high intakes of saturated FAs.

METHODS

The review includes several searches considering the effects of n-3 LCPUFAs in NAFLD in vivo and in vitro models, using the PubMed database from the National Library of Medicine- National Institutes of Health.

RESULT

The LCPUFAs eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid (C22:6 n- 3, DHA) have a positive effect in diminishing liver steatosis, OS, and the levels of aspartate aminotransferase, alanine aminotransferase and pro-inflammatory cytokines, with improvement of insulin sensitivity and adiponectin levels. The molecular pathways described for n-3 LCPUFAs in cellular and animal models and humans include peroxisome proliferator-activated receptor-α activation favouring FA oxidation, diminution of lipogenesis due to sterol responsive element binding protein-1c downregulation and inflammation resolution. Besides, nuclear factor erythroid-2-related factor-2 activation is elicited by n-3 LCPUFA-derived oxidation products producing direct and indirect antioxidant responses, with concomitant anti-fibrogenic action.

CONCLUSION

The discussed effects of n-3 LCPUFA supplementation support its use in NAFLD, although having a limited value in NASH, a contention that may involve n-3 LCPUFA oxygenated derivatives. Clinical trials establishing optimal dosages, intervention times, type of patients and possible synergies with other natural products are needed in future studies.

Suppression of high-fat diet-induced obesity-associated liver mitochondrial dysfunction by docosahexaenoic acid and hydroxytyrosol co-administration

OBJECTIVE

Obesity-induced by high-fat diet (HFD) is associated with liver steatosis, oxidative stress and mitochondrial dysfunction, which can be eluded by the co-administration of the lipid metabolism modulator docosahexaenoic acid (DHA) and the antioxidant hydroxytyrosol (HT).

METHODS

C57BL/6J mice fed a HFD were orally administered either with vehicle, DHA, HT or DHA+HT for 12 weeks. We measured parameters related to insulin resistance, serum lipid levels, liver fatty acid (FA) content and steatosis score, concomitantly with those associated with mitochondrial energy functions modulated by the transcriptional coactivator PGC-1a.

RESULTS

HFD induced insulin resistance, liver steatosis with n-3 FA depletion, and loss of mitochondrial respiratory functions with diminished NAD⁺/NADH ratio and ATP levels compared with CD, with the parallel decrease in the expression of the components of the PGC-1α cascade, namely, PPAR-α, FGF21 and AMPK, effects that were not observed in mice subjected to DHA and HT co-administration.

CONCLUSIONS

Data presented indicate that the combination of DHA and HT prevents the development of liver steatosis and the associated mitochondrial dysfunction induced by HFD, thus strengthening the significance of this protocol as a therapeutic strategy avoiding disease evolution into more irreversible forms characterised by the absence of adequate pharmacological therapy in human obesity.

Time serial transcriptome reveals Cyp2c29 as a key gene in hepatocellular carcinoma development

Objective: Hepatocellular carcinoma (HCC) is a severely lethal cancer that usually originates from chronic liver injury and inflammation. Although progress on diagnosis and treatment is obvious, the cause of HCC remains unclear. In this study, we sought to determine key genes in HCC development. Methods: To identify key regulators during HCC progression, we performed transcriptome sequencing to obtain time series gene expression data from a mouse model with diethylnitrosamine-induced liver tumors and further verified gene expression and function in vitro and in vivo. Results: Among the differentially expressed genes, Cyp2c29 was continuously downregulated during HCC progression. Overexpression of Cyp2c29 suppressed NF-κB activation and proinflammatory cytokine production by increasing the production of 14,15-epoxyeicosatrienoic acid in vitro. Furthermore, overexpression of Cyp2c29 in vivo protected against liver inflammation in mouse models of liver injury induced by both acetaminophen and CCl4. Two human homologs of mouse Cyp2c29, CYP2C8 and CYP2C9, were found to be downregulated in human HCC progression, and their expression was positively correlated with overall survival in patients with HCC (significance: P = 0.046 and 0.0097, respectively). Conclusions: Collectively, through systematic analysis and verification, we determined that Cyp2c29 is a novel gene involved in liver injury and inflammation, which may be a potential biomarker for HCC prevention and prognosis determination.

Dual Farnesoid X Receptor/Soluble Epoxide Hydrolase Modulators Derived from Zafirlukast

The nuclear farnesoid X receptor (FXR) and the enzyme soluble epoxide hydrolase (sEH) are validated molecular targets to treat metabolic disorders such as non-alcoholic steatohepatitis (NASH). Their simultaneous modulation in vivo has demonstrated a triad of anti-NASH effects and thus may generate synergistic efficacy. Here we report dual FXR activators/sEH inhibitors derived from the anti-asthma drug Zafirlukast. Systematic structural optimization of the scaffold has produced favorable dual potency on FXR and sEH while depleting the original cysteinyl leukotriene receptor antagonism of the lead drug. The resulting polypharmacological activity profile holds promise in the treatment of liver-related metabolic diseases.

Fatty acids modulate the expression of pyruvate kinase and arachidonate-lipoxygenase through PPARγ/CYP2C45 pathway: a link to goose fatty liver

Cytochrome P-450 2C45 (CYP2C45) is the most highly expressed cytochrome P-450 isoform in chicken liver, and may play an important role in avian liver biology. However, information regarding the function of CYP2C45 in fatty liver is generally limited. The aim of this study was to investigate the role of CYP2C45 during the development of goose fatty liver. Our result indicated that the transcription of CYP2C45, together with PK and ALOX5, was increased in goose liver upon overfeeding for 19 D (P < 0.05). In goose primary hepatocytes, CYP2C45 RNA expression was also upgraded by the treatment with various chemicals like insulin, the fatty acids, and PPAR agonists (P < 0.05). We also found that both CYP2C45 overexpression and troglitazone treatment could increase the expression of pyruvate kinase (PK) and arachidonate 5-lipoxygenase (ALOX5), and furthermore, showed that the up-regulation of PK and ALOX5 induced by troglitazone could be suppressed by small interfering RNAs targeting CYP2C45 (P < 0.05). These findings suggest that fatty acids treatment and the overfeeding can induce the up-regulation of CYP2C45 expression possibly via PPARγ and that the induction of PK and ALOX5 in goose fatty liver is at least partially attributed to fatty acid-induced expression of CYP2C45. Thus, our data provides an insight into the mechanism by which glycolysis and arachidonic acid metabolism are modulated in goose fatty liver.

Ginsenoside compound K alleviates sodium valproate-induced hepatotoxicity in rats via antioxidant effect, regulation of peroxisome pathway and iron homeostasis

Sodium valproate (SVP) is a first-line treatment for various forms of epilepsy; however, it can cause severe liver injury. Ginsenoside compound K (G-CK) is the main active ingredient of the traditional herbal medicine ginseng. According to our previous research, SVP-induced elevation of ALT and AST levels, as well as pathological changes of liver tissue, was believed to be significantly reversed by G-CK in LiCl-pilocarpine induced epileptic rats. Thus, we aimed to evaluate the protective effect of G-CK on hepatotoxicity caused by SVP. The rats treated with SVP showed liver injury with evident increases in hepatic index, transaminases activity, alkaline phosphatase level, hepatic triglyceride and lipid peroxidation; significant decreases in plasma albumin level and antioxidant capacity; and obvious changes in histopathological and subcellular structures. All of these changes could be mitigated by co-administration with G-CK. Proteomic analysis indicated that hepcidin, soluble epoxide hydrolase (sEH, UniProt ID P80299), and the peroxisome pathway were involved in the hepatoprotective effect of G-CK. Changes in protein expression of hepcidin and sEH were verified by ELISA and Western blot analysis, respectively. In addition, we observed that the hepatic iron rose in SVP group and decreased in the combination group. In summary, our findings demonstrate the clear hepatoprotective effect of G-CK against SVP-induced hepatotoxicity through the antioxidant effect, regulation of peroxisome pathway relying on sEH (P80299) downregulation, as well as regulation of iron homeostasis dependent on hepcidin upregulation.

Docosahexaenoic acid and hydroxytyrosol co-administration fully prevents liver steatosis and related parameters in mice subjected to high-fat diet: A molecular approach

Attenuation of high-fat diet (HFD)-induced liver steatosis is accomplished by different nutritional interventions. Considering that the n-3 PUFA docosahexaenoic acid (DHA) modulates lipid metabolism and the antioxidant hydroxytyrosol (HT) diminishes oxidative stress underlying fatty liver, it is hypothesized that HFD-induced steatosis is suppressed by DHA and HT co-administration. Male C57BL/6J mice were fed a control diet (CD; 10% fat, 20% protein, 70% carbohydrates) or a HFD (60% fat, 20% protein, 20% carbohydrates) for 12 weeks, without and with supplementation of DHA (50 mg/kg/day), HT (5 mg/kg/day) or both. The combined DHA + HT protocol fully prevented liver steatosis and the concomitant pro-inflammatory state induced by HFD, with suppression of lipogenic and oxidative stress signaling, recovery of fatty acid oxidation capacity and enhancement in resolvin availability affording higher inflammation resolution capability. Abrogation of HFD-induced hepatic steatosis by DHA and HT co-administration represents a crucial therapeutic strategy eluding disease progression into stages lacking efficacious handling at present time.

Interactive effects of maternal and weaning high linoleic acid intake on hepatic lipid metabolism, oxylipins profile and hepatic steatosis in offspring

Non-alcoholic fatty liver disease (NAFLD) has been described as a hepatic manifestation of the metabolic syndrome. When several studies correlated maternal linoleic acid (LA) intake with the development of obesity, only few links have been made between n-6 fatty acid (FA) and NAFLD. Herein, we investigated the influence of both maternal and weaning high LA intake on lipid metabolism and susceptibility to develop later metabolic diseases in offspring. Pregnant rats were fed a control-diet (2% LA) or a LA-rich diet (12% LA) during gestation and lactation. At weaning, offspring was assigned to one of the two diets, i.e., either maintained on the same maternal diet or fed the other diet for 6 months. Physiological, biochemical parameters and hepatic FA metabolism were analyzed. We demonstrated that the interaction between the maternal and weaning LA intake altered metabolism in offspring and could lead to hepatic steatosis. This phenotype was associated with altered hepatic FA content and lipid metabolism. Interaction between maternal and weaning LA intake led to a specific pattern of n-6 and n-3 oxylipins that could participate to the development of hepatic steatosis in offspring. Our findings highlight the significant interaction between maternal and weaning high LA intake to predispose offspring to later metabolic disease and support the predictive adaptive response hypothesis.

A dual farnesoid X receptor/soluble epoxide hydrolase modulator treats non-alcoholic steatohepatitis in mice

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are the most prevalent metabolic liver disorders and a serious global health burden. NAFLD/NASH pathogenesis and progression are highly multi-factorial and likely demand a combination of multiple mechanisms to provide a more effective treatment. We have developed a dual farnesoid X receptor agonist (FXRA)/soluble epoxide hydrolase inhibitor (sEHi) to simultaneously address two validated and complementary modes of action in NASH treatment. Here we report the in vivo profiling for this FXRA/sEHi in toxin- and diet-induced rodent NASH models. In streptozotocin-induced NASH as a proof-of-concept study, the experimental FXRA/sEHi drug robustly prevented hepatic steatosis and fibrosis, and improved lipid homeostasis as well as biochemical markers of liver health. In methionine-choline-deficient high-fat diet-induced NASH, FXRA/sEHi treatment reduced hepatic steatosis and fibrosis to levels similar to healthy animals and demonstrated anti-inflammatory activity confirming that dual FXRA/sEHi modulation produces a triad of complementary anti-NASH effects. Our results validate dual FXRA/sEHi modulation as an effective therapeutic strategy to treat NASH and advocates for a combinational drug therapeutic approach for multifactorial liver diseases.

Lipidomic and transcriptomic analysis of western diet-induced nonalcoholic steatohepatitis (NASH) in female Ldlr -/- mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, particularly in obese and type 2 diabetic individuals. NAFLD ranges in severity from benign steatosis to nonalcoholic steatohepatitis (NASH); and NASH can progress to cirrhosis, primary hepatocellular carcinoma (HCC) and liver failure. As such, NAFLD has emerged as a major public health concern. Herein, we used a lipidomic and transcriptomic approach to identify lipid markers associated with western diet (WD) induced NASH in female mice.

METHODS

Female mice (low-density lipoprotein receptor null (Ldlr -/-) were fed a reference or WD diet for 38 and 46 weeks. Transcriptomic and lipidomic approaches, coupled with statistical analyses, were used to identify associations between major NASH markers and transcriptomic & lipidomic markers.

RESULTS

The WD induced all major hallmarks of NASH in female Ldlr -/- mice, including steatosis (SFA, MUFA, MUFA-containing di- and triacylglycerols), inflammation (TNFα), oxidative stress (Ncf2), and fibrosis (Col1A). The WD also increased transcripts associated with membrane remodeling (LpCat), apoptosis & autophagy (Casp1, CtsS), hedgehog (Taz) & notch signaling (Hey1), epithelial-mesenchymal transition (S1004A) and cancer (Gpc3). WD feeding, however, suppressed the expression of the hedgehog inhibitory protein (Hhip), and enzymes involved in triglyceride catabolism (Tgh/Ces3, Ces1g), as well as the hepatic abundance of C18-22 PUFA-containing phosphoglycerolipids (GpCho, GpEtn, GpSer, GpIns). WD feeding also increased hepatic cyclooxygenase (Cox1 & 2) expression and pro-inflammatory ω6 PUFA-derived oxylipins (PGE2), as well as lipid markers of oxidative stress (8-iso-PGF2α). The WD suppressed the hepatic abundance of reparative oxylipins (19, 20-DiHDPA) as well as the expression of enzymes involved in fatty epoxide metabolism (Cyp2C, Ephx).

CONCLUSION

WD-induced NASH in female Ldlr -/- mice was characterized by a massive increase in hepatic neutral and membrane lipids containing SFA and MUFA and a loss of C18-22 PUFA-containing membrane lipids. Moreover, the WD increased hepatic pro-inflammatory oxylipins and suppressed the hepatic abundance of reparative oxylipins. Such global changes in the type and abundance of hepatic lipids likely contributes to tissue remodeling and NASH severity.

Omega-3 fatty acid-derived mediators that control inflammation and tissue homeostasis

Omega-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid, docosapentaenoic acid and docosahexaenoic acid, display a wide range of beneficial effects in humans and animals. Many of the biological functions of PUFAs are mediated via bioactive metabolites produced by fatty acid oxygenases such as cyclooxygenases, lipoxygenases and cytochrome P450 monooxygenases. Liquid chromatography–tandem mass spectrometry-based mediator lipidomics revealed a series of novel bioactive lipid mediators derived from omega-3 PUFAs. Here, we describe recent advances on omega-3 PUFA-derived mediators, mainly focusing on their enzymatic oxygenation pathway, and their biological functions in controlling inflammation and tissue homeostasis.

Stem cell-secreted 14,15- epoxyeicosatrienoic acid rescues cholesterol homeostasis and autophagic flux in Niemann-Pick-type C disease

We previously demonstrated that the direct transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) into the dentate gyrus ameliorated the neurological symptoms of Niemann–Pick type C1 (NPC1)-mutant mice. However, the clinical presentation of NPC1-mutant mice was not fully understood with a molecular mechanism. Here, we found 14,15-epoxyeicosatrienoic acid (14,15-EET), a cytochrome P450 (CYP) metabolite, from hUCB-MSCs and the cerebella of NPC1-mutant mice and investigated the functional consequence of this metabolite. Our screening of the CYP2J family indicated a dysregulation in the CYP system in a cerebellar-specific manner. Moreover, in Purkinje cells, CYP2J6 showed an elevated expression level compared to that of astrocytes, granule cells, and microglia. In this regard, we found that one CYP metabolite, 14,15-EET, acts as a key mediator in ameliorating cholesterol accumulation. In confirming this hypothesis, 14,15-EET treatment reduced the accumulation of cholesterol in human NPC1 patient-derived fibroblasts in vitro by suppressing cholesterol synthesis and ameliorating the impaired autophagic flux. We show that the reduced activity within the CYP system in the cerebellum could cause the neurological symptoms of NPC1 patients, as 14,15-EET treatment significantly rescued cholesterol accumulation and impaired autophagy. We also provide evidence that the intranasal administration of hUCB-MSCs is a highly promising alternative to traumatic surgical transplantation for NPC1 patients.

An acid secreted by stem cells can reduce the excess cholesterol caused by a genetic metabolic disorder. Niemann–Pick type C disease is a rare, inherited condition that causes defective muscular development and progressive neurological degeneration. A key disease mechanism is the excessive accumulation of cholesterol within cells. Kyung-Sun Kang at Seoul National University, South Korea, and co-workers have demonstrated that a metabolite molecule called 14,15-epoxyeicosatrienoic acid (14,15-EET) derived from stem cells from human umbilical cord blood significantly reduced cholesterol in Neimann-Pick Type C mouse models and human cell samples. The team administered the stem cell therapy non-invasively via the nose, and observed significant improvements in motor function in the mice. Experiments in both animals and cells showed that the treatment resulted in reduced cholesterol levels and the correction of defective signalling within cells.

Molecular cloning and characterization of the novel CYP2J2 in dromedary camels (Camelus dromedarius)

Although its economic, cultural and biological importance, many genes haven't been depicted, sequenced or analyzed to date for Camelus dromedarius. In the present paper, the full-length c-DNA of a novel CYP2J2 (GenBank accession number MH511989) was cloned from liver, heart, and kidney mRNA by RACE-PCR. The full-length c-DNA of the cloned CYP2J2 was sequenced and analyzed using bioinformatics methods. The full-length c-DNA sequence was 2135 bp with no introns. The open reading frame (ORF) had 1341 nucleotides which coded for a putative protein of 446 amino acids. The deduced protein is located in the endoplasmic reticulum. It has two transmembrane regions. The nucleotides and deduced amino acids sequences of the cloned CYP2J2 were 1400 nucleotides and 47 amino acids shorter than the predicted homolog respectively. This study is the first description of the putative CYP2J2 gene, which opens the way to a new investigation-so far-never accomplished in Camelus dromedarius.