Targeting nuclear receptors for the treatment of fatty liver disease

Elafibranor alleviates alcohol-related liver fibrosis by restoring intestinal barrier function

We discuss the article by Koizumi et al published in the World Journal of Gastroenterology. Our focus is on the therapeutic targets for fibrosis associated with alcohol-related liver disease (ALD) and the mechanism of action of elafibranor (EFN), a dual agonist of peroxisome proliferator-activated receptor α (PPARα) and peroxisome PPAR δ (PPARδ). EFN is currently in phase III clinical trials for the treatment of metabolic dysfunction-associated fatty liver disease and primary biliary cholangitis. ALD progresses from alcoholic fatty liver to alcoholic steatohepatitis (ASH), with chronic ASH eventually leading to fibrosis, cirrhosis, and, in some cases, hepatocellular carcinoma. The pathogenesis of ALD is driven by hepatic steatosis, oxidative stress, and acetaldehyde toxicity. Alcohol consumption disrupts lipid metabolism by inactivating PPARα, exacerbating the progression of ALD. EFN primarily activates PPARα, promoting lipolysis and β-oxidation in ethanol-stimulated HepG2 cells, which significantly reduces hepatic steatosis, apoptosis, and fibrosis in an ALD mouse model. Additionally, alcohol disrupts the gut-liver axis at several interconnected levels, contributing to a proinflammatory environment in the liver. EFN helps alleviate intestinal hyperpermeability by restoring tight junction protein expression and autophagy, inhibiting apoptosis and inflammatory responses, and enhancing intestinal barrier function through PPARδ activation.

Association between fast eating speed and metabolic dysfunction-associated steatotic liver disease: a multicenter cross-sectional study and meta-analysis

BACKGROUND

With the fast pace of modern life, people have less time for meals, but few studies have examined the association between the habit of fast eating and metabolic diseases.

OBJECTIVE

Combining the results of the current study and the prior ones, we aimed to investigate the possible relationship between fast eating and the risk of metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

This is a sub-analysis of a multicenter cross-sectional study of 1965 participants investigated the association between fast eating and MASLD in Chinese. Fast eating was defined as meal time less than five minutes and participants were divided into three categories based on their self-reported frequency of fast eating: ≤1 time/month, ≤1 time/week and ≥2 times/week. We further conducted a literature search for available studies published before November, 2023 as well as a meta-analysis to investigate the association between fast eating and MASLD.

RESULTS

The proportion of MASLD was 59.3%, 50.5%, and 46.2% in participants with fast eating ≥2 times/week, ≤1 time/week and ≤1 time/month, respectively (P for trend <0.001). The frequency of fast eating was independently associated with risk of MASLD after multiple adjustment for sex, age, demographics, smoking and drinking status, BMI and clinical metabolic parameters (OR, 1.29; 95%CI, 1.09-1.53). Participants who ate fast frequently (≥2 times/week) had 81% higher risk of MASLD (P = 0.011). A meta-analysis of five eligible studies confirmed that frequent fast eating was associated with increased risk of MASLD (pooled OR, 1.22; 95%CI, 1.07-1.39).

CONCLUSIONS

Frequent fast eating was associated with an increased risk of MASLD.

Farnesoid X receptor: From Structure to Function and Its Pharmacology in Liver Fibrosis

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment.

Effects of elafibranor on liver fibrosis and gut barrier function in a mouse model of alcohol-associated liver disease

BACKGROUND

Alcohol-associated liver disease (ALD) is a leading cause of liver-related morbidity and mortality, but there are no therapeutic targets and modalities to prevent ALD-related liver fibrosis. Peroxisome proliferator activated receptor (PPAR) α and δ play a key role in lipid metabolism and intestinal barrier homeostasis, which are major contributors to the pathological progression of ALD. Meanwhile, elafibranor (EFN), which is a dual PPARα and PPARδ agonist, has reached a phase III clinical trial for the treatment of metabolic dysfunction-associated steatotic liver disease and primary biliary cholangitis. However, the benefits of EFN for ALD treatment is unknown.

AIM

To evaluate the inhibitory effects of EFN on liver fibrosis and gut-intestinal barrier dysfunction in an ALD mouse model.

METHODS

ALD-related liver fibrosis was induced in female C57BL/6J mice by feeding a 2.5% ethanol (EtOH)-containing Lieber-DeCarli liquid diet and intraperitoneally injecting carbon tetrachloride thrice weekly (1 mL/kg) for 8 weeks. EFN (3 and 10 mg/kg/day) was orally administered during the experimental period. Histological and molecular analyses were performed to assess the effect of EFN on steatohepatitis, fibrosis, and intestinal barrier integrity. The EFN effects on HepG2 lipotoxicity and Caco-2 barrier function were evaluated by cell-based assays.

RESULTS

The hepatic steatosis, apoptosis, and fibrosis in the ALD mice model were significantly attenuated by EFN treatment. EFN promoted lipolysis and β-oxidation and enhanced autophagic and antioxidant capacities in EtOH-stimulated HepG2 cells, primarily through PPARα activation. Moreover, EFN inhibited the Kupffer cell-mediated inflammatory response, with blunted hepatic exposure to lipopolysaccharide (LPS) and toll like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling. EFN improved intestinal hyperpermeability by restoring tight junction proteins and autophagy and by inhibiting apoptosis and proinflammatory responses. The protective effect on intestinal barrier function in the EtOH-stimulated Caco-2 cells was predominantly mediated by PPARδ activation.

CONCLUSION

EFN reduced ALD-related fibrosis by inhibiting lipid accumulation and apoptosis, enhancing hepatocyte autophagic and antioxidant capacities, and suppressing LPS/TLR4/NF-κB-mediated inflammatory responses by restoring intestinal barrier function.

The Expression of Genes Related to Reverse Cholesterol Transport and Leptin Receptor Pathways in Peripheral Blood Mononuclear Cells Are Decreased in Morbid Obesity and Related to Liver Function

Obesity is frequently accompanied by non-alcoholic fatty liver disease (NAFLD). These two diseases are associated with altered lipid metabolism, in which reverse cholesterol transport (LXRα/ABCA1/ABCG1) and leptin response (leptin receptor (Ob-Rb)/Sam68) are involved. The two pathways were evaluated in peripheral blood mononuclear cells (PBMCs) from 86 patients with morbid obesity (MO) before and six months after Roux-en-Y gastric bypass (RYGB) and 38 non-obese subjects. In the LXRα pathway, LXRα, ABCA1, and ABCG1 mRNA expressions were decreased in MO compared to non-obese subjects (p < 0.001, respectively). Ob-Rb was decreased (p < 0.001), whereas Sam68 was increased (p < 0.001) in MO. RYGB did not change mRNA gene expressions. In the MO group, the LXRα pathway (LXRα/ABCA1/ABCG1) negatively correlated with obesity-related variables (weight, body mass index, and hip), inflammation (C-reactive protein), and liver function (alanine-aminotransferase, alkaline phosphatase, and fatty liver index), and positively with serum albumin. In the Ob-R pathway, Ob-Rb and Sam68 negatively correlated with alanine-aminotransferase and positively with albumin. The alteration of LXRα and Ob-R pathways may play an important role in NAFLD development in MO. It is possible that MO patients may require more than 6 months following RYBGB to normalize gene expression related to reverse cholesterol transport or leptin responsiveness.

New Insights into the Role of PPARγ in Skin Physiopathology

Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor expressed in many tissues, including skin, where it is essential for maintaining skin barrier permeability, regulating cell proliferation/differentiation, and modulating antioxidant and inflammatory responses upon ligand binding. Therefore, PPARγ activation has important implications for skin homeostasis. Over the past 20 years, with increasing interest in the role of PPARs in skin physiopathology, considerable effort has been devoted to the development of PPARγ ligands as a therapeutic option for skin inflammatory disorders. In addition, PPARγ also regulates sebocyte differentiation and lipid production, making it a potential target for inflammatory sebaceous disorders such as acne. A large number of studies suggest that PPARγ also acts as a skin tumor suppressor in both melanoma and non-melanoma skin cancers, but its role in tumorigenesis remains controversial. In this review, we have summarized the current state of research into the role of PPARγ in skin health and disease and how this may provide a starting point for the development of more potent and selective PPARγ ligands with a low toxicity profile, thereby reducing unwanted side effects.

Bifenthrin induces changes in clinical poisoning symptoms, oxidative stress, DNA damage, histological characteristics, and transcriptome in Chinese giant salamander (Andrias davidianus) larvae

Bifenthrin (BF) is a broad-spectrum insecticide that has gained widespread use due to its high effectiveness. However, there is limited research on the potential toxic effects of bifenthrin pollution on amphibians. This study aimed to investigate the 50 % lethal concentration (LC50) and safety concentration of Chinese giant salamanders (CGS) exposed to BF (at 0, 6.25,12.5,25 and 50 μg/L BF) for 96 h. Subsequently, CGS were exposed to BF (at 0, 0.04, and 4 μg/L BF) for one week to investigate its toxic effects. Clinical poisoning symptoms, liver pathology, oxidative stress factors, DNA damage, and transcriptome differences were observed and analyzed. The results indicate that exposure to BF at 4 μg/L significantly decreased the adenosine-triphosphate (ATP), superoxide dismutase (SOD), glutathione (GSH), and catalase (CAT) contents in the brain, liver, and kidney of CGS. Additionally, the study found that the malondialdehyde (MDA), reactive oxygen species (ROS), and 8-hydroxydeoxyguanosine (8-OHdG) contents were increased. The liver tissue exhibited significant inflammatory reactions and structural malformations. RNA-seq analysis of the liver showed that BF caused abnormal antioxidant indices of CGS. This affected molecular function genes such as catalytic activity, ATP-dependent activity, metabolic processes, signaling and immune system processes, behavior, and detoxification, which were significantly upregulated, resulting in the differential genes significantly enriched in the calcium signaling pathway, PPARα signaling pathway and NF-kB signaling pathway. The results suggest that BF induces the abnormal production of free radicals, which overwhelms the body's self-defense system, leading to varying degrees of oxidative stress. This can result in oxidative damage, DNA damage, abnormal lipid metabolism, autoimmune diseases, clinical poisoning symptoms, and tissue inflammation. This work provides a theoretical basis for the rational application of bifenthrin and environmental risk assessment, as well as scientific guidance for the conservation of amphibian populations.

Future therapeutic perspectives in nonalcoholic fatty liver disease: a focus on nuclear receptors, a promising therapeutic target

Non-alcoholic fatty liver disease (NAFLD) is a major public health problem worldwide, with an increasing incidence, secondary to the increasing incidence of obesity and diabetes, from a very young age. It is associated with metabolic and cardiovascular disorders, as components of the metabolic syndrome (MS). NAFLD is the hepatic manifestation of MS. The pathogenesis of the disease is multifactorial and complex, involving genetic, metabolic, but also environmental factors. Currently, nuclear receptors (NRs) represent a promising therapeutic target in the treatment of non-alcoholic steatohepatitis (NASH). Of these, the most studied receptor was the liver X receptor (LXR), which would have great potential in the treatment of metabolic diseases, namely hypercholesterolemia, atherosclerosis, and NAFLD. However, the therapeutic use of NRs is restricted in medical practice for two reasons: limited knowledge of the structure of the receptor and its inability to modulate certain actions in the target organs and genes. One problem is the understanding of the function and structure of the N-terminal domain which has a major transcriptional activation function (AF1).

The activation of HAMP promotes colorectal cancer cell proliferation through zinc-mediated upregulation of SMAD4 expression

Background

Colorectal cancer (CRC) poses a significant challenge in digestive system diseases, and emerging evidence underscores the critical role of zinc metabolism in its progression. This study aimed to investigate the clinical implications of genes at the intersection of zinc metabolism and CRC.

Methods

We downloaded CRC prognosis-related genes and zinc metabolism-related genes from public databases. Then, the overlapping genes were screened out, and bioinformatics analysis was performed to obtain the hub gene associated with CRC prognosis. Subsequently, in vitro assays were carried out to investigate the expression of this hub gene and its exact mechanism between zinc metabolism and CRC.

Results

HAMP was identified as the hub CRC prognostic gene from overlapping zinc metabolism-related and CRC prognostic genes. In vitro analysis showed HAMP was over-expressed in CRC, and its knockdown inhibited RKO and HCT-116 cell invasion and migration significantly. ZnSO4 induced HAMP up-regulation to promote cell proliferation, while TPEN decreased HAMP expression to inhibit cell proliferation. Importantly, we further found that ZnSO4 enhanced SMAD4 expression to augment HAMP promoter activity and promote cell proliferation in CRC.

Conclusions

HAMP stands out as an independent prognostic factor in CRC, representing a potential therapeutic target. Its intricate regulation by zinc, particularly through the modulation of SMAD4, unveils a novel avenue for understanding CRC biology. This study provides valuable insights into the interplay between zinc metabolism, HAMP, and CRC, offering promising clinical indicators for CRC patients. The findings present a compelling case for further exploration and development of targeted therapeutic strategies in CRC management.

Natural Products in the Modulation of Farnesoid X Receptor Against Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a global health concern with a high prevalence and increasing economic burden, but official medicine remains unavailable. Farnesoid X receptor (FXR), a nuclear receptor member, is one of the most promising drug targets for NAFLD therapy that plays a crucial role in modulating bile acid, glucose, and lipid homeostasis, as well as inhibits hepatic inflammation and fibrosis. However, the rejection of the FXR agonist, obecholic acid, by the Food and Drug Administration for treating hepatic fibrosis raises a question about the functions of FXR in NAFLD progression and the therapeutic strategy to be used. Natural products, such as FXR modulators, have become the focus of attention for NAFLD therapy with fewer adverse reactions. The anti-NAFLD mechanisms seem to act as FXR agonists and antagonists or are involved in the FXR signaling pathway activation, indicating a promising target of FXR therapeutic prospects using natural products. This review discusses the effective mechanisms of FXR in NAFLD alleviation, and summarizes currently available natural products such as silymarin, glycyrrhizin, cycloastragenol, berberine, and gypenosides, for targeting FXR, which can facilitate development of naturally targeted drug by medicinal specialists for effective treatment of NAFLD.

Causal effects from nonalcoholic fatty liver disease on cholelithiasis: A mendelian randomization study

Background and Aims

Both nonalcoholic fatty liver disease (NAFLD) and cholelithiasis are highly prevalent hepatobiliary diseases with risk of progression into severe outcomes. Considering the close relationship between liver and gallbladder in anatomy and physiology, a potential causal relationship between NAFLD and cholelithiasis has been speculated.

Methods

Mendelian randomization (MR) was employed using genome-wide association study (GWAS) summary statistics in Million Veteran Program (MVP) for NAFLD, and statistics in UK biobank for cholelithiasis.

Results

Our results demonstrate that NAFLD has a causal effect on cholelithiasis risk (OR, 1.003; 95%CI, 1.000-1.006; p = 0.03). We also performed the sensitivity analysis and heterogeneity test to ensure the accuracy of outcome and avoid the reverse causality.

Conclusion

NAFLD should be regarded as a potential pathogenic factor in pathogenesis study of cholelithiasis, and be considered in assessment and treatment of cholelithiasis.

The roles of nuclear receptors in cholesterol metabolism and reverse cholesterol transport in nonalcoholic fatty liver disease

As the most prevalent chronic liver disease globally, NAFLD encompasses a pathological process that ranges from simple steatosis to NASH, fibrosis, cirrhosis, and HCC, closely associated with numerous extrahepatic diseases. While the initial etiology was believed to be hepatocyte injury caused by lipid toxicity from accumulated triglycerides, recent studies suggest that an imbalance of cholesterol homeostasis is of greater significance. The role of nuclear receptors in regulating liver cholesterol homeostasis has been demonstrated to be crucial. This review summarizes the roles and regulatory mechanisms of nuclear receptors in the 3 main aspects of cholesterol production, excretion, and storage in the liver, as well as their cross talk in reverse cholesterol transport. It is hoped that this review will offer new insights and theoretical foundations for the study of the pathogenesis and progression of NAFLD and provide new research directions for extrahepatic diseases associated with NAFLD.

The Role of Nuclear Receptors in the Pathogenesis and Treatment of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a global health burden closely linked to insulin resistance, obesity, and type 2 diabetes. The complex pathophysiology of NAFLD involves multiple cellular pathways and molecular factors. Nuclear receptors (NRs) have emerged as crucial regulators of lipid metabolism and inflammation in NAFLD, offering potential therapeutic targets for NAFLD. Targeting PPARs and FXRs has shown promise in ameliorating NAFLD symptoms and halting disease progression. However, further investigation is needed to address side effects and personalize therapy approaches. This review summarizes the current understanding of the involvement of NRs in the pathogenesis of NAFLD and explores their therapeutic potential. We discuss the role of several NRs in modulating lipid homeostasis in the liver, including peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptors (FXRs), REV-ERB, hepatocyte nuclear factor 4α (HNF4α), constitutive androstane receptor (CAR) and pregnane X receptor (PXR).The expanding knowledge of NRs in NAFLD offers new avenues for targeted therapies, necessitating exploration of novel treatment strategies and optimization of existing approaches to combat this increasingly prevalent disease.

Danlou Recipe promotes cholesterol efflux in macrophages RAW264.7 and reverses cholesterol transport in mice with hyperlipidemia induced by P407

INTRODUCTION

Liver X Receptor (LXR) agonists could attenuate the development of atherosclerosis but bring excess lipid accumulation in the liver. Danlou Recipe was believed to be a benefit for improving the lipid profile. Thus, it is unclear whether Danlou Recipe could attenuate hyperlipidemia without excess lipid accumulated in the liver of mice. This study aimed to clarify if Danlou Recipe could alleviate the progression of hyperlipidemia in mice without extra lipids accumulated in the liver.

METHODS

Male murine macrophage RAW264.7 cells and murine peritoneal macrophages were used for the in vitro experiments. Cellular cholesterol efflux was determined using the fluorescent cholesterol labeling method. Those genes involved in lipid metabolism were evaluated by qRT-PCR and western blotting respectively. In vivo, a mouse model of hyperlipidemia induced by P407 was used to figure out the effect of Danlou Recipe on reverse cholesterol transport (RCT) and hyperlipidemia. Ethanol extract of Danlou tablet (EEDL) was prepared by extracting the whole powder of Danlou Prescription from ethanol, and the chemical composition was analyzed by ultra-performance liquid chromatography (UPLC).

RESULTS

EEDL inhibits the formation of RAW264.7 macrophage-derived foam cells, and promotes ABCA1/apoA1 conducted cholesterol efflux in RAW264.7 macrophages and mouse peritoneal macrophages. In the P407-induced hyperlipidemia mouse model, oral administration of EEDL can promote RCT in vivo and improve fatty liver induced by a high-fat diet. Consistent with the findings in vitro, EEDL promotes RCT by upregulating the LXR activities.

CONCLUSION

Our results demonstrate that EEDL has the potential for targeting RCT/LXR in the treatment of lipid metabolism disorders to be developed as a safe and effective therapy.

Recent advances in drug delivery systems for targeting brain tumors

Brain tumor accounts for about 1.6% of incidence and 2.5% of mortality of all tumors, and the median survival for brain tumor patients is only about 20 months. The treatment for brain tumor still faces many challenges, such as the blood-brain barrier (BBB), blood-brain tumor barrier (BBTB), the overexpressed efflux pumps, the infiltration, invasion, high heterogeneity of tumor cells, drug resistance and immune escape caused by tumor microenvironment (TME) and cancer stem cells (CSC). This review attempts to clarify the challenges for multi-functional nano drug delivery systems (NDDS) to cross the BBB and target the cancer cells or organelles, and also provides a brief description of the different types of targeted multi-functional NDDS that have shown potential for success in delivering drugs to the brain. Further, this review also summarizes the research progress of multi-functional NDDS in the combination therapy of brain tumors from the following sections, the combination of chemotherapy drugs, chemotherapy-chemodynamic combination therapy, chemotherapy-immunization combination therapy, and chemotherapy-gene combination therapy. We also provide an insight into the recent advances in designing multi-functional NDDS for combination therapy.

Intracellular spatiotemporal metabolism in connection to target engagement

The metabolism in eukaryotic cells is a highly ordered system involving various cellular compartments, which fluctuates based on physiological rhythms. Organelles, as the smallest independent sub-cell unit, are important contributors to cell metabolism and drug metabolism, collectively designated intracellular metabolism. However, disruption of intracellular spatiotemporal metabolism can lead to disease development and progression, as well as drug treatment interference. In this review, we systematically discuss spatiotemporal metabolism in cells and cell subpopulations. In particular, we focused on metabolism compartmentalization and physiological rhythms, including the variation and regulation of metabolic enzymes, metabolic pathways, and metabolites. Additionally, the intricate relationship among intracellular spatiotemporal metabolism, metabolism-related diseases, and drug therapy/toxicity has been discussed. Finally, approaches and strategies for intracellular spatiotemporal metabolism analysis and potential target identification are introduced, along with examples of potential new drug design based on this.

Influence of deoxynivalenol and zearalenone on the immunohistochemical expression of oestrogen receptors and liver enzyme genes in vivo in prepubertal gilts

Deoxynivalenol (DON) and zearalenone (ZEN) are often detected in plant materials used to produce feed for pre-pubertal gilts. Daily exposure to small amounts of these mycotoxins causes subclinical conditions in pigs and affects various biological processes (e.g. mycotoxin biotransformation). The aim of this preclinical study was to evaluate the effect of low monotonic doses of DON and ZEN (12 µg/kg body weight-BW-and 40 µg/kg BW, respectively), administered alone or in combination to 36 prepubertal gilts for 42 days, on the degree of immunohistochemical expression of oestrogen receptors (ERs) in the liver and the mRNA expression of genes encoding selected liver enzymes during biotransformation processes. The level of expression of the analysed genes proves that the tested mycotoxins exhibit variable biological activity at different stages of biotransformation. The biological activity of low doses of mycotoxins determines their metabolic activity. Therefore, taking into account the impact of low doses of mycotoxins on energy-intensive processes and their endogenous metabolism, it seems that the observed situation may lead to the activation of adaptation mechanisms.

Establishment of Novel Mouse Model of Dietary NASH Rapidly Progressing into Liver Cirrhosis and Tumors

Non-alcoholic steatohepatitis (NASH), which is the most severe manifestation of non-alcoholic fatty liver disease (NAFLD), has been recognized as a major hepatocellular carcinoma (HCC) catalyst. However, the molecular mechanism of NASH-liver fibrosis-HCC sequence remains unclear and a specific and effective treatment for NASH has not yet been established. The progress in this field depends on the availability of reliable preclinical models which show the steady progression to NASH, liver cirrhosis, and HCC. However, most of the NASH mouse models that have been described to date develop NASH generally for more than 24 weeks and there is an uncertainty of HCC development. To overcome such shortcomings of experimental NASH studies, we established a novel NASH-HCC mouse model with very high reproducibility, generality, and convenience. We treated male C57BL/6J mice with a newly developed choline-deficient and methionine-restricted high-fat diet, named OYC-NASH2 diet, for 60 weeks. Treatment of OYC-NASH2 diet for 3 weeks revealed marked steatosis, lobular inflammation, and fibrosis, histologically diagnosed as NASH. Liver cirrhosis was observed in all mice with 48-week treatment. Liver nodules emerged at 12 weeks of the treatment, > 2 mm diameter liver tumors developed in all mice at 24 weeks of the treatment and HCC appeared after 36-week treatment. In conclusion, our rapidly progressive and highly reproducible NASH-liver cirrhosis-HCC model is helpful for preclinical development and research on the pathogenesis of human NAFLD-NASH-HCC. Our mouse model would be useful for the development of novel chemicals for NASH-HCC-targeted therapies.

The great potential of flavonoids as candidate drugs for NAFLD

Non-alcoholic fatty liver disease (NAFLD) has a global prevalence of approximately 25 % and is associated with high morbidity and high mortality. NAFLD is a leading cause of cirrhosis and hepatocellular carcinoma. Its pathophysiology is complex and still poorly understood, and there are no drugs used in the clinic to specifically treat NAFLD. Its pathogenesis involves the accumulation of excess lipids in the liver, leading to lipid metabolism disorders and inflammation. Phytochemicals with the potential to prevent or treat excess lipid accumulation have recently received increasing attention, as they are potentially more suitable for long-term use than are traditional therapeutic compounds. In this review, we summarize the classification, biochemical properties, and biological functions of flavonoids and how they are used in the treatment of NAFLD. Highlighting the roles and pharmacological uses of these compounds will be of importance for enhancing the prevention and treatment of NAFLD.

Citrin Deficiency: Clinical and Nutritional Features

SLC25A13 gene mutations are responsible for diseases related to citrin deficiency (CD), such as neonatal intrahepatic cholestasis caused by citrin deficiency and adult-onset type II citrullinemia (CTLN2). From childhood to adulthood, CD patients are apparently healthy due to metabolic compensation with peculiar dietary habits-disliking high-carbohydrate foods and liking fat and protein-rich foods. Carbohydrate overload and alcohol consumption may trigger the sudden onset of CTLN2, inducing hyperammonemia and consciousness disturbance. Well-compensated asymptomatic CD patients are sometimes diagnosed as having non-obese (lean) non-alcoholic fatty liver disease and steatohepatitis, which have the risk of developing into liver cirrhosis and hepatocellular carcinoma. CD-induced fatty liver demonstrates significant suppression of peroxisome proliferator-activated receptor α and its downstream enzymes/proteins involved in fatty acid transport and oxidation and triglyceride secretion as a very low-density lipoprotein. Nutritional therapy is an essential and important treatment of CD, and medium-chain triglycerides oil and sodium pyruvate are useful for preventing hyperammonemia. We need to avoid the use of glycerol for treating brain edema by hyperammonemia. This review summarizes the clinical and nutritional features of CD-associated fatty liver disease and promising nutritional interventions.

Targeting Liver X Receptors for the Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) refers to a range of conditions in which excess lipids accumulate in the liver, possibly leading to serious hepatic manifestations such as steatohepatitis, fibrosis/cirrhosis and cancer. Despite its increasing prevalence and significant impact on liver disease-associated mortality worldwide, no medication has been approved for the treatment of NAFLD yet. Liver X receptors α/β (LXRα and LXRβ) are lipid-activated nuclear receptors that serve as master regulators of lipid homeostasis and play pivotal roles in controlling various metabolic processes, including lipid metabolism, inflammation and immune response. Of note, NAFLD progression is characterized by increased accumulation of triglycerides and cholesterol, hepatic de novo lipogenesis, mitochondrial dysfunction and augmented inflammation, all of which are highly attributed to dysregulated LXR signaling. Thus, targeting LXRs may provide promising strategies for the treatment of NAFLD. However, emerging evidence has revealed that modulating the activity of LXRs has various metabolic consequences, as the main functions of LXRs can distinctively vary in a cell type-dependent manner. Therefore, understanding how LXRs in the liver integrate various signaling pathways and regulate metabolic homeostasis from a cellular perspective using recent advances in research may provide new insights into therapeutic strategies for NAFLD and associated metabolic diseases.

Complementary gene regulation by NRF1 and NRF2 protects against hepatic cholesterol overload

Hepatic cholesterol overload promotes steatohepatitis. Insufficient understanding of liver stress defense impedes therapy development. Here, we elucidate the role of stress defense transcription factors, nuclear factor erythroid 2 related factor-1 (NRF1) and -2 (NRF2), in counteracting cholesterol-linked liver stress. Using a diet that increases liver cholesterol storage, expression profiles and phenotypes of liver from mice with hepatocyte deficiency of NRF1, NRF2, or both are compared with controls, and chromatin immunoprecipitation sequencing is undertaken to identify target genes. Results show NRF1 and NRF2 co-regulate genes that eliminate cholesterol and mitigate inflammation and oxidative damage. Combined deficiency, but not deficiency of either alone, results in severe steatohepatitis, hepatic cholesterol overload and crystallization, altered bile acid metabolism, and decreased biliary cholesterol. Moreover, therapeutic effects of NRF2-activating drug bardoxolone require NRF1 and are supplemented by NRF1 overexpression. Thus, we discover complementary gene programming by NRF1 and NRF2 that counteract cholesterol-associated fatty liver disease progression.

PPAR-γ signaling in nonalcoholic fatty liver disease: Pathogenesis and therapeutic targets

Non-alcoholic fatty liver disease (NAFLD), currently the leading cause of global chronic liver disease, has emerged as a major public health problem, more efficient therapeutics of which are thus urgently needed. Peroxisome proliferator-activated receptor γ (PPAR-γ), ligand-activated transcription factors of the nuclear hormone receptor superfamily, is considered a crucial metabolic regulator of hepatic lipid metabolism and inflammation. The role of PPAR-γ in the pathogenesis of NAFLD is gradually being recognized. Here, we outline the involvement of PPAR-γ in the pathogenesis of NAFLD through adipogenesis, insulin resistance, inflammation, oxidative stress, endoplasmic reticulum stress, and fibrosis. In addition, the evidence for PPAR-γ- targeted therapy for NAFLD are summarized. Altogether, PPAR-γ is a promising therapeutic target for NAFLD, and the development of drugs that can balance the beneficial and undesirable effects of PPAR-γ will bring new light to NAFLD patients.

Dietary Fat Composition Affects Hepatic Angiogenesis and Lymphangiogenesis in Hepatitis C Virus Core Gene Transgenic Mice

Introduction

Previous research has demonstrated that an isocaloric diet rich in trans-fatty acid (TFA), saturated fatty acid (SFA), and cholesterol (Chol) promoted steatosis-derived hepatic tumorigenesis in hepatitis C virus core gene transgenic (HCVcpTg) mice in different manners. Growth factor signaling and ensuing angiogenesis/lymphangiogenesis are key factors in hepatic tumorigenesis that have become recent therapeutic targets for hepatocellular carcinoma. However, the influence of dietary fat composition on these factors remains unclear. This study investigated whether the type of dietary fat would have a specific impact on hepatic angiogenesis/lymphangiogenesis in HCVcpTg mice.

Methods

Male HCVcpTg mice were treated with a control diet, an isocaloric diet containing 1.5% cholesterol (Chol diet), or a diet replacing soybean oil with hydrogenated coconut oil (SFA diet) for a period of 15 months or with shortening (TFA diet) for 5 months. The degree of angiogenesis/lymphangiogenesis and the expression of growth factors, including fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF), were evaluated in non-tumorous liver tissues using quantitative mRNA measurement, immunoblot analysis, and immunohistochemistry.

Results

Long-term feeding of SFA and TFA diets to HCVcpTg mice increased the expressions of vascular endothelial cell indicators, such as CD31 and TEK receptor tyrosine kinase, in addition to lymphatic vessel endothelial hyaluronan receptor 1, indicating that angiogenesis/lymphangiogenesis were upregulated only by these fatty acid-enriched diets. This promoting effect correlated with elevated VEGF-C and FGF receptor 2 and 3 levels in the liver. c-Jun N-terminal kinase (JNK) and hypoxia-inducible factor (HIF) 1α, both key regulators of VEGF-C expression, were enhanced in the SFA- and TFA-rich diet groups as well. The Chol diet significantly increased the expressions of such growth factors as FGF2 and PDGF subunit B, without any detectable impact on angiogenesis/lymphangiogenesis.

Conclusion

This study revealed that diets rich in SFA and TFA, but not Chol, might stimulate hepatic angiogenesis/lymphangiogenesis mainly through the JNK-HIF1α-VEGF-C axis. Our observations indicate the importance of dietary fat species for preventing hepatic tumorigenesis.

Development of the Rabbit NASH Model Resembling Human NASH and Atherosclerosis

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease which may progress into liver fibrosis and cancer. Since NASH patients have a high prevalence of atherosclerosis and ensuing cardiovascular diseases, simultaneous management of NASH and atherosclerosis is required. Currently, rodents are the most common animal models for NASH and accompanying liver fibrosis, but there are great differences in lipoprotein profiles between rodents and humans, which makes it difficult to reproduce the pathology of NASH patients with atherosclerosis. Rabbits can be a promising candidate for assessing NASH and atherosclerosis because lipoprotein metabolism is more similar to humans compared with rodents. To develop the NASH model using rabbits, we treated the Japanese White rabbit with a newly developed high-fat high-cholesterol diet (HFHCD) containing palm oil 7.5%, cholesterol 0.5%, and ferrous citrate 0.5% for 16 weeks. HFHCD-fed rabbits exhibited NASH at 8 weeks after commencing the treatment and developed advanced fibrosis by the 14th week of treatment. In addition to hypercholesterolemia, atherosclerotic lesion developed in the aorta after 8 weeks. Therefore, this rabbit NASH model might contribute to exploring the concurrent treatment options for human NASH and atherosclerosis.

Diethyldithiocarbamate inhibits the activation of hepatic stellate cells via PPARα/FABP1 in mice with non-alcoholic steatohepatitis

Activation of hepatic stellate cells (HSCs) is the main course of liver fibrosis which is positively correlated with adverse clinical outcomes in non-alcoholic steatohepatitis (NASH). Diethyldithiocarbamate (DDC) attenuates NASH related liver fibrosis in mice, but its underlying mechanisms remains unclear. In this study, the data showed that DDC inhibited the activation of HSCs in high fat choline-deficient, L-amino acid-defined (CDAA) diet induced NASH. Double Immunofluorescence analysis showed that the baseline expression of peroxisome proliferator-activated receptor α (PPARα) is high in HSCs in normal mouse liver and notably decreases in the NASH liver, indicating that PPARα might be associated with the activation of HSCs. While, DDC upregulated PPARα in HSCs in the NASH liver. Mixture of free fatty acid was used to induce steatosis of hepatocytes. Human HSCs (LX-2 cells) were activated after co-cultured with steatotic hepatocytes, and DDC inhibited the activation of LX-2 cells. Meanwhile, DDC upregulated PPARα and FABP1, and promoted the accumulation of LDs in LX-2 cells. PPARα small interfering RNA blocked these effect of DDC. These findings suggest that PPARα is associated with the activation of HSCs in the context of NASH. DDC improves NASH related fibrosis through inhibiting the activation of HSCs via PPARα/FABP1.

Peptide Helix-Y12 as Potential Effector for Peroxisome Proliferator-Activated Receptors

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors involved in the regulation of lipids and glucose metabolism, and immune response. Therefore, they have been considered pharmacological targets for treating metabolic diseases, such as dyslipidemia, atherosclerosis, and non-alcoholic fatty liver disease. However, the available synthetic ligands of PPARs have mild to significant side effects, generating the necessity to identify new molecules that are selective PPAR ligands with specific biological responses. This study aimed to evaluate some components of the atheroprotective and hepatoprotective HB-ATV-8 nanoparticles [the amphipathic peptide Helix-Y¹², thermozeaxanthin, thermozeaxanthin-13, thermozeaxanthin-15, and a set of glycolipids], as possible ligands of PPARs through blind molecular docking. According to the change in free energy upon protein-ligand binding, ∆G _b, thermozeaxanthins show a more favorable interaction with PPARs, followed by Helix-Y¹². Moreover, Helix-Y¹² interacts with most parts of the Y-shaped ligand-binding domain (LBD), surrounding helix 3 of PPARs, and reaching helix 12 of PPARα and PPARγ. As previously reported for other ligands, Tyr314 and Tyr464 of PPARα interact with Helix-Y¹² through hydrogen bonds. Several PPARα's amino acids are involved in the ligand binding by hydrophobic interactions. Furthermore, we identified additional PPARs' amino acids interacting with Helix-Y¹² through hydrogen bonds still not reported for known ligands. Our results show that, from the studied ligand set, the Helix-Y¹² peptide and Tzeaxs have the most significant probability of binding to the PPARs' LBD, suggesting novel ligands for PPARs.

Using epigenomics to understand cellular responses to environmental influences in diseases

It is a generally accepted model that environmental influences can exert their effects, at least in part, by changing the molecular regulators of transcription that are described as epigenetic. As there is biochemical evidence that some epigenetic regulators of transcription can maintain their states long term and through cell division, an epigenetic model encompasses the idea of maintenance of the effect of an exposure long after it is no longer present. The evidence supporting this model is mostly from the observation of alterations of molecular regulators of transcription following exposures. With the understanding that the interpretation of these associations is more complex than originally recognised, this model may be oversimplistic; therefore, adopting novel perspectives and experimental approaches when examining how environmental exposures are linked to phenotypes may prove worthwhile. In this review, we have chosen to use the example of nonalcoholic fatty liver disease (NAFLD), a common, complex human disease with strong environmental and genetic influences. We describe how epigenomic approaches combined with emerging functional genetic and single-cell genomic techniques are poised to generate new insights into the pathogenesis of environmentally influenced human disease phenotypes exemplified by NAFLD.

The ameliorating effect of withaferin A on high-fat diet-induced non-alcoholic fatty liver disease by acting as an LXR/FXR dual receptor activator

Introduction: Non-alcoholic fatty liver disease (NAFLD) incidence has been rapidly increasing, and it has emerged as one of the major diseases of the modern world. NAFLD constitutes a simple fatty liver to chronic non-alcoholic steatohepatitis (NASH), which often leads to liver fibrosis or cirrhosis, a serious health condition with limited treatment options. Many a time, NAFLD progresses to fatal hepatocellular carcinoma (HCC). Nuclear receptors (NRs), such as liver X receptor-α (LXR-α) and closely associated farnesoid X receptor (FXR), are ligand-inducible transcription factors that regulate various metabolism-associated gene expressions and repression and play a major role in controlling the pathophysiology of the human liver. Withaferin A is a multifaceted and potent natural dietary compound with huge beneficial properties and plays a vital role as an anti-inflammatory molecule. Methods: In vivo: Swill albino mice were fed with western diet and sugar water (WDSW) for 12, 16, and 20 weeks with suitable controls. Post necropsy, liver enzymes (AST, ALT, and ALP) and lipid profile were measured by commercially available kits using a semi-auto analyzer in serum samples. Liver histology was assessed using H&E and MTS stains to check the inflammation and fibrosis, respectively, using paraffin-embedded sections and mRNA expressions of these markers were measured using qRT-PCR method. TGF-β1 levels in serum samples were quantified by ELISA. In vitro: Steatosis was induced in HepG2 and Huh7 cells using free fatty acids [Sodium Palmitate (SP) and Oleate (OA)]. After induction, the cells were treated with Withaferin A in dose-dependent manner (1, 2.5, and 5 μM, respectively). In vitro steatosis was confirmed by Oil-Red-O staining. Molecular Docking: Studies were conducted using Auto Dock Vina software to check the binding affinity of Withaferin-A to LXR-α and FXR. Results: We explored the dual receptor-activating nature of Withaferin A using docking studies, which potently improves high-fat diet-induced NAFLD in mice and suppresses diet-induced hepatic inflammation and liver fibrosis via LXR/FXR. Our in vitro studies also indicated that Withaferin A inhibits lipid droplet accumulation in sodium palmitate and oleate-treated HepG2 and Huh7 cells, which may occur through LXR-α and FXR-mediated signaling pathways. Withaferin A is a known inhibitor of NF-κB-mediated inflammation. Intriguingly, both LXR-α and FXR activation inhibits inflammation and fibrosis by negatively regulating NF-κB. Additionally, Withaferin A treatment significantly inhibited TGF-β-induced gene expression, which contributes to reduced hepatic fibrosis. Discussion: Thus, the LXR/ FXR dual receptor activator Withaferin A improves both NAFLD-associated liver inflammation and fibrosis in mouse models and under in vitro conditions, which makes Withaferin A a possibly potent pharmacological and therapeutic agent for the treatment of diet-induced NAFLD.

Pemafibrate improves liver dysfunction and non-invasive surrogates for liver fibrosis in patients with non-alcoholic fatty liver disease with hypertriglyceridemia: a multicenter study

BACKGROUND

This retrospective, multicenter study evaluated the effect of pemafibrate treatment on liver function and fibrosis by liver function tests (LFTs) and various fibrotic biomarkers including FibroScan in non-alcoholic fatty liver disease (NAFLD) with hypertriglyceridemia.

METHODS

A total of 138 NAFLD patients treated with pemafibrate at three hospitals between September 2018 and April 2021 were included. To evaluate the effect of pemafibrate treatment, FibroScan-aspartate aminotransferase (FAST) score, a novel index of steatohepatitis that can be calculated based on the aspartate aminotransferase (AST) value, controlled attenuation parameter (CAP), and liver stiffness measurement (LSM) was used.

RESULTS

Serum TG levels were significantly decreased 4 weeks after pemafibrate treatment (p = 0.003). The levels of AST (p = 0.038), alanine aminotransferase (ALT) (p = 0.003), and gamma-glutamyl transferase (GGT) (p = 0.047) also significantly diminished 12 weeks after pemafibrate administration compared to before administration (p < 0.05). However, serum HDL-cholesterol (p = 0.193), LDL-cholesterol (p = 0.967), and eGFR (p = 0.909) levels were not significantly altered 12 weeks after pemafibrate administration. In addition, the fibrosis biomarkers' Type IV collagen (p = 0.753) and FIB-4 index (p = 0.333) did not significantly differ, while Autotaxin (p = 0.006) and the AST-to-platelet ratio index (APRI) (p = 0.003) significantly decreased 48 weeks after pemafibrate administration. No significant reductions in LSM (p = 0.959) and CAP (p = 0.266) were detected using FibroScan 48 weeks after pemafibrate administration. FAST score was significantly improved (p = 0.0475).

CONCLUSION

Pemafibrate improved LFTs, including fibrotic biomarkers and FAST score, due to the hepatic anti-inflammatory effect, suggesting that pemafibrate may prevent disease progression in NAFLD patients with hypertriglyceridemia.

Chaetomorpha linum polysaccharides alleviate NAFLD in mice by enhancing the PPARα/CPT-1/MCAD signaling

BACKGROUND

Green algae contain many polysaccharides. However, there is no information on whether Chaetomorpha linum polysaccharides (CLP) can modulate lipid and glucose metabolism.

MATERIAL AND METHODS

CLP were extracted from chlorella and their components were characterized. Male C57BL/6 mice were randomized and provided with control chow as the control, or high fat diet (HFD) to induce nonalcoholic fatty liver disease (NAFLD). NAFLD mice were treated orally with water as the HFD group or with 50 or 150 mg/kg CLP daily for 10 weeks. The impact of CLP treatment on lipid and glucose metabolism and the PPARα signaling was examined by histology, Western blotting and biochemistry.

RESULTS

CLP mainly contained arabinogalactan sulfate. Compared with the control, HFD feeding increased body weights, lipid droplet liver deposition and induced hyperlipidemia, liver functional impairment and glucose intolerance in mice. Treatment with CLP, particularly with a higher dose of CLP, limited the HFD-increased body weights and liver lipid droplet deposition, mitigated the HFD-induced hyperlipidemia and improved liver function and glucose tolerance in mice. Mechanistically, feeding with HFD dramatically decreased the expression of liver PPARα, CPT-1, and MCAD, but treatment with CLP enhanced their expression in a trend of dose-dependent in mice.

CONCLUSIONS

These findings indicated that CLP treatment alleviated the gain in body weights, NAFLD, and glucose intolerance in mice after HFD feeding by enhancing the PPARα/CPT-1/MCAD signaling.

Role of intestinal flora in primary sclerosing cholangitis and its potential therapeutic value

Primary sclerosing cholangitis (PSC) is an autoimmune disease characterized by chronic cholestasis, a persistent inflammation of the bile ducts that leads to sclerotic occlusion and cholestasis. Gut microbes, consisting of microorganisms colonized in the human gut, play an important role in nutrient intake, metabolic homeostasis, immune regulation, and immune regulation; however, their presence might aid PSC development. Studies have found that gut-liver axis interactions also play an important role in the pathogenesis of PSC. Patients with PSC have considerably reduced intestinal flora diversity and increased abundance of potentially pathogenic bacteria. Dysbiosis of the intestinal flora leads to increased intestinal permeability, homing of intestinal lymphocytes, entry of bacteria and their associated metabolites, such as bile acids, into the liver, stimulation of hepatic immune activation, and promotion of PSC. Currently, PSC effective treatment is lacking. However, a number of studies have recently investigated the targeted modulation of gut microbes for the treatment of various liver diseases (alcoholic liver disease, metabolic fatty liver, cirrhosis, and autoimmune liver disease). In addition, antibiotics, fecal microbiota transplantation, and probiotics have been reported as successful PSC therapies as well as for the treatment of gut dysbiosis, suggesting their effectiveness for PSC treatment. Therefore, this review briefly summarizes the role of intestinal flora in PSC with the aim of providing new insights into PSC treatment.

Higher Responsiveness for Women, High Transaminase Levels, and Fat Percentage to Pemafibrate Treatment for NAFLD

Aim: Pemafibrate (PEM) is a novel selective peroxisome proliferator-activated receptor alpha modulator that is effective for hypertriglyceridemia accompanying non-alcoholic fatty liver disease (HTG-NAFLD). This study aimed to identify the predictors of PEM efficacy for HTG-NAFLD in clinical practice. Methods: We retrospectively enrolled 88 HTG-NAFLD patients treated with PEM for 6 months for the analysis of routine blood and body composition testing. A PEM response was defined as a decrease in serum alanine aminotransferase (ALT) of >30% compared with pre-treatment level. The clinical features related to PEM responsiveness were statistically tested between responders and non-responders. Results: All 88 patients completed the 6 month drug regimen without any adverse effects. PEM treatment significantly decreased liver enzymes, triglycerides, and total cholesterol levels, without any detectable impact on body weight or body composition. Comparisons of baseline clinical features revealed female and greater aspartate aminotransferase (AST), ALT, and fat mass % levels to be significantly associated with a PEM response. The optimal cut-off values to predict responders as determined by receiver operating characteristic analysis were AST 45 U/L, ALT 60 U/L, and fat mass 37%. Conclusions: Female HTG-NAFLD patients with higher transaminase and fat mass % levels may be preferentially indicated for PEM treatment. Additional large-scale prospective studies are warranted to verify our results.

Red Pepper Seeds Inhibit Hepatic Lipid Accumulation by Inducing Autophagy via AMPK Activation

Although the red pepper and its seeds have been studied for metabolic diseases, the effects and potential mechanisms of red pepper seed extract (RPS) on hepatic lipid accumulation are not yet completely understood. This study aimed to evaluate the inhibitory effect of RPS on hepatic lipid accumulation via autophagy. C57BL/6 mice were fed a high-fat diet (HFD) or a HFD supplemented with RPS. RPS treatment inhibited hepatic lipid accumulation by suppressing lipogenesis, inducing hepatic autophagic flux, and activating AMPK in HFD-fed mice. To investigate the effect of RPS on an oleic acid (OA)-induced hepatic steatosis cell model, HepG2 cells were incubated in a high-glucose medium and OA, followed by RPS treatment. RPS treatment decreased OA-induced lipid accumulation and reduced the expression of lipogenesis-associated proteins. Autophagic flux dramatically increased in the RPS-treated group. RPS phosphorylated AMPK in a dose-dependent manner, thereby dephosphorylated mTOR. Autophagy inhibition with 3-methyladenine (3-MA) antagonized RPS-induced suppression of lipogenesis-related protein expressions. Moreover, the knockdown of endogenous AMPK also antagonized the RPS-induced regulation of lipid accumulation and autophagy. Our findings provide new insights into the beneficial effects of RPS on hepatic lipid accumulation through the AMPK-dependent autophagy-mediated downregulation of lipogenesis.

Poria cocos polysaccharides rescue pyroptosis-driven gut vascular barrier disruption in order to alleviates non-alcoholic steatohepatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Poria cocos polysaccharides (PCP) are abundant in Poria cocos (Schw.) Wolf (Poria). This is a common traditional Chinese medicine used to treat gastrointestinal and liver diseases. Poria cocos dispel dampness and enhance gastrointestinal functions, strongly affecting the treatment of non-alcoholic fatty liver disease. Still, the mechanism is not yet clear.

AIM OF THE STUDY

The latest research found that protecting the integrity of the intestinal barrier can slow down the progression of non-alcoholic fatty liver disease (NAFLD). Hence, our research ought to explore the protective mechanism of PCP on the intestinal barrier under a high-fat diet and to clarify the relationship between intestinal barrier damage and steatohepatitis.

MATERIALS AND METHODS

H&E staining was done to evaluate pathological damage, whereas Nile red and oil red O staining was conducted to evaluate hepatic fat infiltration. Immunofluorescence staining and immunohistochemical staining were used to detect protein expression and locations. Bone marrow-derived macrophages were isolated for in vitro experiments. ONOO- and ROS fluorescent probes and MDA, SOD, and GSH kits assessed the levels of nitrogen and oxidative stress. LPS levels were detected with a Limulus Amebocyte Lysate assay. The Western blot analysis and reverse transcription-quantitative PCR detected the expression of related proteins and genes. The Elisa kit detected the level of the inflammatory factors in the cell supernatant. For the vivo NAFLD experiments, in briefly, mice were randomly chosen to receive either a High-fat diet or control diet for 12 weeks. Drug treatments started after 4 weeks of feeding. Zebrafish larvae were raised separately in fish water or 7 mM thioacetamide as the control or model group for approximately 72 h. In the therapy groups, different concentrations of PCP were added to the culture environment at the same time.

RESULTS

In zebrafish, we determined the safe concentration of PCP and found that PCP could effectively reduce the pathological damage in the liver and intestines induced by the NAFLD model. In mice, PCP could slow down weight gain, hyperlipidemia, and liver steatosis caused by a high-fat diet. More importantly, PCP could reduce the destruction of the gut-vascular barrier and the translocation of endotoxins caused by a high-fat diet. Further, we found that PCP could inhibit intestinal pyroptosis by regulating PARP-1. Pyroptosis inhibitors, such as MCC950, could effectively protect the intestinal and liver damage induced by a high-fat diet. We also found that pyroptosis mainly occurred in intestinal macrophages. PCP could effectively improve the survival rate of bone marrow-derived macrophages in a high-fat environment and inhibit pyroptosis.

CONCLUSIONS

These results indicated that PCP inhibited the pyroptosis of small intestinal macrophages to protect the intestinal barrier integrity under a high-fat diet. This resulted in decreased endotoxin translocation and progression of steatohepatitis.

A new perspective on NAFLD: Focusing on the crosstalk between peroxisome proliferator-activated receptor alpha (PPARα) and farnesoid X receptor (FXR)

Nonalcoholic fatty liver disease (NAFLD) is primarily caused by abnormal lipid metabolism and the accumulation of triglycerides in the liver. NAFLD is also associated with hepatic steatosis and nutritional and energy imbalances and is a chronic liver disease associated with a number of factors. Nuclear receptors play a key role in balancing energy and nutrient metabolism, and the peroxisome proliferator-activated receptor alpha (PPARα) and farnesoid X receptor (FXR) regulate lipid metabolism genes, controlling hepatocyte lipid utilization and regulating bile acid (BA) synthesis and transport. They play an important role in lipid metabolism and BA homeostasis. At present, PPARα and FXR are the most promising targets for the treatment of NAFLD among nuclear receptors. This review focuses on the crosstalk mechanisms and transcriptional regulation of PPARα and FXR in the pathogenesis of NAFLD and summarizes PPARα and FXR drugs in clinical trials, laying a theoretical foundation for the targeted treatment of NAFLD and the development of novel therapeutic strategies.

Akkermansia muciniphila Enhances Egg Quality and the Lipid Profile of Egg Yolk by Improving Lipid Metabolism

Akkermansia muciniphila (A. muciniphila) has shown potential as a probiotic for the prevention and treatment of non-alcoholic fatty liver disease in both humans and mice. However, relatively little is known about the effects of A. muciniphila on lipid metabolism, productivity, and product quality in laying hens. In this study, we explored whether A. muciniphila supplementation could improve lipid metabolism and egg quality in laying hens and sought to identify the underlying mechanism. In the first experiment, 80 Hy-Line Brown laying hens were divided into four groups, one of which was fed a normal diet (control group), while the other three groups were administered a high-energy, low-protein diet to induce fatty liver hemorrhagic syndrome (FLHS). Among the three FLHS groups, one was treated with phosphate-buffered saline, one with live A. muciniphila, and one with pasteurized A. muciniphila. In the second experiment, 140 Hy-Line Brown laying hens were divided into two groups and respectively fed a basal diet supplemented or not with A. muciniphila lyophilized powder. The results showed that, in laying hens with FLHS, treatment with either live or pasteurized A. muciniphila efficiently decreased body weight, abdominal fat deposition, and lipid content in both serum and the liver; downregulated the mRNA expression of lipid synthesis-related genes and upregulated that of lipid transport-related genes in the liver; promoted the growth of short-chain fatty acids (SCFAs)-producing microorganisms and increased the cecal SCFAs content; and improved the yolk lipid profile. Additionally, the supplementation of lyophilized powder of A. muciniphila to aged laying hens reduced abdominal fat deposition and total cholesterol (TC) levels in both serum and the liver, suppressed the mRNA expression of cholesterol synthesis-related genes in the liver, reduced TC content in the yolk, increased eggshell thickness, and reshaped the composition of the gut microbiota. Collectively, our findings demonstrated that A. muciniphila can modulate lipid metabolism, thereby, promoting laying hen health as well as egg quality and nutritive value. Live, pasteurized, and lyophilized A. muciniphila preparations all have the potential for use as additives for improving laying hen production.

Clinically Relevant Dose of Pemafibrate, a Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator (SPPARMα), Lowers Serum Triglyceride Levels by Targeting Hepatic PPARα in Mice

Pemafibrate (PEM) is a novel lipid-lowering drug classified as a selective peroxisome proliferator-activated receptor α (PPARα) modulator whose binding efficiency to PPARα is superior to that of fibrates. This agent is also useful for non-alcoholic fatty liver disease and primary biliary cholangitis with dyslipidemia. The dose of PEM used in some previous mouse experiments is often much higher than the clinical dose in humans; however, the precise mechanism of reduced serum triglyceride (TG) for the clinical dose of PEM has not been fully evaluated. To address this issue, PEM at a clinically relevant dose (0.1 mg/kg/day) or relatively high dose (0.3 mg/kg/day) was administered to male C57BL/6J mice for 14 days. Clinical dose PEM sufficiently lowered circulating TG levels without apparent hepatotoxicity in mice, likely due to hepatic PPARα stimulation and the enhancement of fatty acid uptake and β-oxidation. Interestingly, PPARα was activated only in the liver by PEM and not in other tissues. The clinical dose of PEM also increased serum/hepatic fibroblast growth factor 21 (FGF21) without enhancing hepatic lipid peroxide 4-hydroxynonenal or inflammatory signaling. In conclusion, a clinically relevant dose of PEM in mice efficiently and safely reduced serum TG and increased FGF21 targeting hepatic PPARα. These findings may help explain the multiple beneficial effects of PEM observed in the clinical setting.

Natural PPARs agonists for the treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a general term for a series of liver diseases including simple steatosis, non-alcoholic steatohepatitis, liver fibrosis, which is closely related to metabolic syndrome. The pathogenesis of NAFLD is relatively complex, which has gradually changed from the previous 'two-hit' hypothesis to the current "multiple hits" hypothesis. However, there is currently no approved treatment for NAFLD in clinic, highlighting the urgent need for drug development. Peroxisome proliferator activated receptors (PPARs) are members of the nuclear receptor superfamily, whose different subtypes have been proved to regulate different stages of NAFLD, thus becoming promising drug targets for NAFLD. As important sources of drug development, natural products have been proven to treat NAFLD through multiple pathways and multiple targets. In this paper, we outline the regulatory role of PPARs in NAFLD, and summarize some natural products that target PPARs to ameliorate NAFLD, in order to provide reference for drug development of NAFLD.

The regulatory role and mechanism of autophagy in energy metabolism-related hepatic fibrosis

Hepatic fibrosis is a key pathological process of chronic liver diseases, caused by alcohol, toxic and aberrant energy metabolism. It progresses to cirrhosis or even hepatic carcinoma without effective treatment. Studies have shown that autophagy has important regulatory effects on hepatic stellate cells (HSCs) energy metabolism, and then affect the activation state of HSCs. Autophagy maintains hepatic energy homeostasis, and the dysregulation of autophagy can lead to the activation of HSCs and the occurrence and development of hepatic fibrosis. It is necessary to explore the mechanism of autophagy in energy metabolism-related hepatic fibrosis. Herein, the current study summarizes the regulating mechanisms of autophagy through different targets and signal pathways in energy metabolism-related hepatic fibrosis, and discusses the regulatory effect of autophagy by natural plant-derived, endogenous and synthetic compounds for the treatment of hepatic fibrosis. A better comprehension of autophagy in hepatic stellate cells energy metabolism-related hepatic fibrosis may provide effective intervention of hepatic fibrosis, explore the potential clinical strategies and promote the drug treatment of hepatic fibrosis.

Therapeutic Potential of Semaglutide, a Newer GLP-1 Receptor Agonist, in Abating Obesity, Non-Alcoholic Steatohepatitis and Neurodegenerative diseases: A Narrative Review

INTRODUCTION

Semaglutide, a peptidic GLP-1 receptor agonist, has been clinically approved for treatment of type 2 diabetes mellitus and is available in subcutaneous and oral dosage form. Diabetes, insulin resistance, and obesity are responsible for the pathological manifestations of non-alcoholic steatohepatitis (NASH). Similarly, insulin resistance in brain is also responsible for neurodegeneration and impaired cognitive functions.

BACKGROUND

Observations from phase-3 clinical trials like SUSTAIN and PIONEER indicated anti-obesity potential of semaglutide, which was established in STEP trials. Various pre-clinical and phase-2 studies have indicated the therapeutic potential of semaglutide in non-alcoholic steatohepatitis and neurodegenerative disorders like Parkinson's and Alzheimer's disease.

DISCUSSION

Significant weight reduction ability of semaglutide has been demonstrated in various phase-3 clinical trials, for which recently semaglutide became the first long-acting GLP-1 receptor agonist to be approved by the United States Food and Drug Administration for management of obesity. Various pre-clinical and clinical studies have revealed the hepatoprotective effect of semaglutide in NASH and neuroprotective effect in Parkinson's and Alzheimer's disease.

CONCLUSION

Many GLP-1 receptor agonists have shown hepatoprotective and neuroprotective activity in animal and human trials. As semaglutide is an already clinically approved drug, successful human trials would hasten its inclusion into therapeutic treatment of NASH and neurodegenerative diseases. Semaglutide improves insulin resistance, insulin signalling pathway, and reduce body weight which are responsible for prevention or progression of NASH and neurodegenerative diseases.

Carry-Over of Zearalenone and Its Metabolites to Intestinal Tissues and the Expression of CYP1A1 and GSTπ1 in the Colon of Gilts before Puberty

The objective of this study was to evaluate whether low doses of zearalenone (ZEN) affect the carry-over of ZEN and its metabolites to intestinal tissues and the expression of CYP1A1 and GSTπ1 in the large intestine. Prepubertal gilts (with a BW of up to 14.5 kg) were exposed in group ZEN to daily ZEN5 doses of 5 μg/kg BW (n = 15); in group ZEN10, 10 μg/kg BW (n = 15); in group ZEN15, 15 μg/kg BW (n = 15); or were administered a placebo (group C, n = 15) throughout the experiment. After euthanasia, tissues were sampled on exposure days 7, 21, and 42 (D1, D2, and D3, respectively). The results confirmed that the administered ZEN doses (LOAEL, NOAEL, and MABEL) were appropriate to reliably assess the carry-over of ZEN. Based on the observations made during 42 days of exposure to pure ZEN, it can be hypothesized that all mycotoxins (ZEN, α-zearalenol, and β-zearalenol) contribute to a balance between intestinal cells and the expression of selected genes encoding enzymes that participate in biotransformation processes in the large intestine; modulate feminization processes in prepubertal gilts; and elicit flexible, adaptive responses of the macroorganism to mycotoxin exposure at the analyzed doses.

Acidic Activated Charcoal Prevents Obesity and Insulin Resistance in High-Fat Diet-Fed Mice

Obesity is becoming a major public health problem worldwide. Making charcoal from wood (“Sumi-yaki”) has been a traditional activity in the southern part of Nagano Prefecture for centuries, with activated charcoal having reported detoxifying effects. However, it is unclear whether activated charcoal also possesses anti-obesity properties. Additionally, since activated charcoal is usually alkaline and might be affected by gastric juice, we evaluated the effect of acidic activated charcoal on high-fat diet (HFD)-induced obesity. This study demonstrated that co-treatment of acidic activated charcoal with a HFD significantly improved obesity and insulin resistance in mice in a dose-dependent manner. Metabolomic analysis of cecal contents revealed that neutral lipids, cholesterol, and bile acids were excreted at markedly higher levels in feces with charcoal treatment. Moreover, the hepatic expressions of genes encoding cholesterol 7 alpha-hydroxylase and hydroxymethylglutaryl-CoA reductase/synthase 1 were up-regulated by activated charcoal, likely reflecting the enhanced excretions from the intestine and the enterohepatic circulation of cholesterol and bile acids. No damage or abnormalities were detected in the gastrointestinal tract, liver, pancreas, and lung. In conclusion, acidic activated charcoal may be able to attenuate HFD-induced weight gain and insulin resistance without serious adverse effects. These findings indicate a novel function of charcoal to prevent obesity, metabolic syndrome, and related diseases.

FXR: structures, biology, and drug development for NASH and fibrosis diseases

The nuclear receptor farnesoid-X-receptor (FXR) plays an essential role in bile acid, glucose, and lipid homeostasis. In the last two decades, several diseases, such as obesity, type 2 diabetes, nonalcoholic fatty liver disease, cholestasis, and chronic inflammatory diseases of the liver and intestine, have been revealed to be associated with alterations in FXR functions. FXR has become a promising therapeutic drug target, particularly for enterohepatic diseases. Despite the large number of FXR modulators reported, only obeticholic acid (OCA) has been approved for primary biliary cholangitis (PBC) therapy as FXR modulator. In this review, we summarize the structure and function of FXR, the development of FXR modulators, and the structure-activity relationships of FXR modulators. Based on the structural analysis, we discuss potential strategies for developing future therapeutic FXR modulators to overcome current limitations, providing new perspectives for enterohepatic and metabolic diseases treatment.

Updates on novel pharmacotherapeutics for the treatment of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD), characterized with hepatocellular steatosis, ballooning, lobular inflammation, fibrotic progression, and insulin resistance. NASH may progress to cirrhosis and hepatocellular carcinoma (HCC), which are the major indications for liver transplantation and the causes for mortality. Thus far, there are no approved pharmacotherapeutics for the treatment of NASH. Given the complexity of NASH pathogenesis at multifaceted aspects, such as lipotoxicity, inflammation, insulin resistance, mitochondrial dysfunction and fibrotic progression, pharmacotherapeutics under investigation target different key pathogenic pathways to gain either the resolution of steatohepatitis or regression of fibrosis, ideally both. Varieties of pharmacologic candidates have been tested in clinical trials and have generated some positive results. On the other hand, recent failure or termination of a few phase II and III trials is disappointing in this field. In face to growing challenges in pharmaceutical development, this review intends to summarize the latest data of new medications which have completed phase II or III trials, and discuss the rationale and preliminary results of several combinatory options. It is anticipated that with improved understanding of NASH pathogenesis and critical endpoints, efficient pharmacotherapeutics will be available for the treatment of NASH with an acceptable safety profile.

Salvia miltiorrhiza Bge. (Danshen) in the Treating Non-alcoholic Fatty Liver Disease Based on the Regulator of Metabolic Targets

Non-alcoholic fatty liver disease (NAFLD) is rapidly prevalent due to its strong association with increased metabolic syndrome such as cardio- and cerebrovascular disorders and diabetes. Few drugs can meet the growing disease burden of NAFLD. Salvia miltiorrhiza Bge. (Danshen) have been used for over 2,000 years in clinical trials to treat NAFLD and metabolic syndrome disease without clarified defined mechanisms. Metabolic targets restored metabolic homeostasis in patients with NAFLD and improved steatosis by reducing the delivery of metabolic substrates to liver as a promising way. Here we systematic review evidence showing that Danshen against NAFLD through diverse and crossing mechanisms based on metabolic targets. A synopsis of the phytochemistry and pharmacokinetic of Danshen and the mechanisms of metabolic targets regulating the progression of NAFLD is initially provided, followed by the pharmacological activity of Danshen in the management NAFLD. And then, the possible mechanisms of Danshen in the management of NAFLD based on metabolic targets are elucidated. Specifically, the metabolic targets c-Jun N-terminal kinases (JNK), sterol regulatory element-binding protein-1c (SREBP-1c), nuclear translocation carbohydrate response element–binding protein (ChREBP) related with lipid metabolism pathway, and peroxisome proliferator-activated receptors (PPARs), cytochrome P450 (CYP) and the others associated with pleiotropic metabolism will be discussed. Finally, providing a critical assessment of the preclinic and clinic model and the molecular mechanism in NAFLD.

2-Step PLT16-AST44 method: Simplified liver fibrosis detection system in patients with non-alcoholic fatty liver disease

AIM

Accurate detection of the hepatic fibrosis stage is essential to estimate the outcome of patients with non-alcoholic fatty liver disease (NAFLD). Many formulas, biomarkers, and imaging tests are being developed to predict advanced liver fibrosis without performing a liver biopsy. However, these tests do not have high efficiency in detecting early-stage hepatic fibrosis. Therefore, we aimed to detect the presence of hepatic fibrosis (≥F1) merely by using only standard clinical markers.

METHODS

A total of 436 patients with NAFLD who underwent liver biopsy were retrospectively enrolled as the discovery cohort (316 patients) and the validation cohort (120 patients). Liver biopsy and laboratory data were matched to extract simple parameters for identifying ≥F1.

RESULTS

We developed a novel simplified ≥F1 detecting system, designated as 2-Step PLT16-AST44 method, where (1) PLT of 16 × 10⁴ /μl or less, or (2) PLT greater than 16 × 10⁴ /μl and AST greater than 44 U/L is determined as having ≥F1 fibrosis. The 2-Step PLT16-AST44 method had a sensitivity of 68%, a specificity of 90%, a positive predictive value (PPV) of 97%, a negative predictive value (NPV) of 40%, and an accuracy of 72% to detect ≥F1 fibrosis in the discovery cohort. Validation studies further supported these results. Despite its simplicity, the 2-Step PLT16-AST44 method's power to detect ≥F1 fibrosis in total NAFLD patients was comparable to hyaluronic acid, type 4 collagen 7S, FIB-4, and APRI.

CONCLUSIONS

We propose the 2-Step PLT16-AST44 method as a simple and beneficial early-stage hepatic fibrosis detection system.

Nuclear Receptors Linking Metabolism, Inflammation, and Fibrosis in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) and its progressive form nonalcoholic steatohepatitis (NASH) comprise a spectrum of chronic liver diseases in the global population that can lead to end-stage liver disease and hepatocellular carcinoma (HCC). NAFLD is closely linked to the metabolic syndrome, and comorbidities such as type 2 diabetes, obesity and insulin resistance aggravate liver disease, while NAFLD promotes cardiovascular risk in affected patients. The pathomechanisms of NAFLD are multifaceted, combining hepatic factors including lipotoxicity, mechanisms of cell death and liver inflammation with extrahepatic factors including metabolic disturbance and dysbiosis. Nuclear receptors (NRs) are a family of ligand-controlled transcription factors that regulate glucose, fat and cholesterol homeostasis and modulate innate immune cell functions, including liver macrophages. In parallel with metabolic derangement in NAFLD, altered NR signaling is frequently observed and might be involved in the pathogenesis. Therapeutically, clinical data indicate that single drug targets thus far have been insufficient for reaching patient-relevant endpoints. Therefore, combinatorial treatment strategies with multiple drug targets or drugs with multiple mechanisms of actions could possibly bring advantages, by providing a more holistic therapeutic approach. In this context, peroxisome proliferator-activated receptors (PPARs) and other NRs are of great interest as they are involved in wide-ranging and multi-organ activities associated with NASH progression or regression. In this review, we summarize recent advances in understanding the pathogenesis of NAFLD, focusing on mechanisms of cell death, immunometabolism and the role of NRs. We outline novel therapeutic strategies and discuss remaining challenges.