Ferroptosis and metabolic dysfunction-associated fatty liver disease: Is there a link?

IL6 Derived from Macrophages under Intermittent Hypoxia Exacerbates NAFLD by Promoting Ferroptosis via MARCH3-Led Ubiquitylation of GPX4

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by intermittent hypoxia (IH) and is associated with the occurrence and development of nonalcoholic fatty liver disease (NAFLD). However, the specific mechanism by which OSA induces NAFLD remains unclear. Therefore, effective interventions are lacking. This study aims to investigate the role and mechanism of ferroptosis in OSA-related NAFLD using clinical data analyses, cell-based molecular experiments, and animal experiments. Indicators of liver function, lipid accumulation, and ferroptosis are also examined. RNA-seq, qPCR, western blotting, gene intervention, and E3 ligase prediction using UbiBrowser and co-IP are used to explore the potential underlying mechanisms. The results show that ferroptosis increases in the liver tissues of patients with OSA. Chronic IH promotes NAFLD progression in mice and is alleviated by a ferroptosis inhibitor Fer-1. The increased secretion of IL6 by macrophages can promote the expression of MARCH3 in hepatocytes under intermittent conditions, and subsequently promote the ubiquitination and degradation of GPX4 to regulate ferroptosis and lipid accumulation in hepatocytes. Hence, targeted inhibition of MARCH3 may alleviate IH-induced ferroptosis and lipid accumulation in liver tissues and inhibit the progression of NAFLD.

GA receptor targeted chitosan oligosaccharide polymer nanoparticles improve non-alcoholic fatty liver disease by inhibiting ferroptosis

Excessive iron in the liver may exacerbate Non-alcoholic fatty liver disease (NAFLD) by increasing the risk of liver cell expansion, inflammation and fibrosis. Ferroptosis in liver cells may lead the progression of simple fatty liver degeneration to steatohepatitis (NASH). More and more studies shew that ferroptosis played a crucial role in the pathological process of NAFLD. Based on the mechanism of ferroptosis, this study first synthesized a liver targeted 18-β-Glycyrrhetinic-acid-chitosan oligosaccharide -N-acetylcysteine polymer (GCNp), and further curcumin (Cur) was used as model drug to prepare Cur loaded nanodelivery system (GCNp-Cur NPs). The particle size of GCNp-Cur NPs was 132.5 ± 9.8 nm, PDI was 0.148 ± 0.026 and the potential was 23.8 mV. GCNp-Cur NPs can regulate the GPX4/GSH pathway, inhibit lipid peroxidation, restore cellular oxidative environment, reduce free Fe2+, improve cellular lipid metabolism and iron metabolism, thereby NPs inhibited liver cell ferroptosis through multiple pathways. Additionally, GCNp-Cur NPs could also alleviate liver tissue lipid accumulation and oxidative damage, delaying disease progression, and providing a new method and theoretical basis for the treatment of NAFLD.

Identification of regulatory networks and crosstalk factors in brown adipose tissue and liver of a cold-exposed cardiometabolic mouse model

BACKGROUND

Activation of brown adipose tissue (BAT) has gained attention due to its ability to dissipate energy and counteract cardiometabolic diseases (CMDs).

METHODS

This study investigated the consequences of cold exposure on the BAT and liver proteomes of an established CMD mouse model based on LDL receptor-deficient (LdlrKO) mice fed a high-fat, high-sucrose, high-cholesterol diet for 16 weeks. We analyzed energy metabolism in vivo and performed untargeted proteomics on BAT and liver of LdlrKO mice maintained at 22 °C or 5 °C for 7 days.

RESULTS

We identified several dysregulated pathways, miRNAs, and transcription factors in BAT and liver of cold-exposed Ldlrko mice that have not been previously described in this context. Networks of regulatory interactions based on shared downstream targets and analysis of ligand-receptor pairs identified fibrinogen alpha chain (FGA) and fibronectin 1 (FN1) as potential crosstalk factors between BAT and liver in response to cold exposure. Importantly, genetic variations in the genes encoding FGA and FN1 have been associated with cardiometabolic-related phenotypes and traits in humans.

DISCUSSION

This study describes the key factors, pathways, and regulatory networks involved in the crosstalk between BAT and the liver in a cold-exposed CMD mouse model. These findings may provide a basis for future studies aimed at testing whether molecular mediators, as well as regulatory and signaling mechanisms involved in tissue adaption upon cold exposure, could represent a target in cardiometabolic disorders.

Ferroptosis promotes valproate-induced liver steatosis in vitro and in vivo

Valproic acid (VPA), a common antiepileptic drug, can cause liver steatosis after long-term therapy. However, an impact of ferroptosis on VPA-induced liver steatosis has not been investigated. In the study, treatment with VPA promoted ferroptosis in the livers of mice by elevating ferrous iron (Fe2+) levels derived from the increased absorption by transferrin receptor 1 (TFR1) and the decreased storage by ferritin (FTH1 and FTL), disrupting the redox balance via reduced levels of solute carrier family 7 member 11 (SLC7A11), glutathione (GSH), and glutathione peroxidase 4 (GPX4), and augmenting acyl-CoA synthetase long-chain family member 4 (ACSL4) -mediated lipid peroxide generation, accompanied by enhanced liver steatosis. All the changes were significantly reversed by co-treatment with an iron-chelating agent, deferoxamine mesylate (DFO) and a ferroptosis inhibitor, ferrostatin-1 (Fer-1). Similarly, the increases in Fe2+, TFR1, and ACSL4 levels, as well as the decreases in GSH, GPX4, and ferroportin (FPN) levels, were detected in VPA-treated HepG2 cells. These changes were also attenuated after co-treatment with Fer-1. It demonstrates that ferroptosis promotes VPA-induced liver steatosis through iron overload, inhibition of the GSH-GPX4 axis, and upregulation of ACSL4. It offers a potential therapy targeting ferroptosis for patients with liver steatosis following VPA treatment.

Discovery of a NCOA4 Degrader for Labile Iron-Dependent Ferroptosis Inhibition

Ferroptosis, a distinctive form of programmed cell death, has been implicated in numerous pathological conditions, and its inhibition is considered a promising therapeutic strategy. Currently, there is a scarcity of efficient antagonists for directly regulating intracellular ferrous iron. Ferritinophagy, an essential process for supplying intracellular labile iron, relies on nuclear receptor coactivator 4 (NCOA4), a selective autophagy receptor for the ferritin iron storage complex, thus playing a pivotal role in ferritinophagy. In this study, we reported a novel von Hippel-Lindau-based NCOA4 degrader, V3, as a potent ferroptosis inhibitor with an intracellular ferrous iron inhibition mechanism. V3 significantly reduced NCOA4 levels and downregulated intracellular ferrous iron (Fe2+) levels, thereby effectively suppressing ferroptosis induced by multiple pathways within cells and alleviating liver damage. This research presents a chemical knockdown tool targeting NCOA4 for further exploration into intracellular ferrous iron in ferroptosis, offering a promising therapeutic avenue for ferroptosis-related acute liver injury.

Metformin Regulates Cardiac Ferroptosis to Reduce Metabolic Syndrome-Induced Cardiac Dysfunction

High-fat diet-induced metabolic syndrome (MetS) is closely associated with cardiac dysfunction. Recent research studies have indicated a potential association between MetS and ferroptosis. Furthermore, metformin can alleviate MetS-induced cardiac ferroptosis. Metformin is a classic biguanide anti-diabetic drug that has protective effects on cardiovascular diseases, which extend beyond its indirect glycemic control. This study aimed to assess whether MetS mediates cardiac ferroptosis, thereby causing oxidative stress and mitochondrial dysfunction. The results revealed that metformin can mitigate cardiac reactive oxygen species and mitochondrial damage, thereby preserving cardiac function. Mechanistic analysis revealed that metformin upregulates the expression of cardiac Nrf2. Moreover, Nrf2 downregulation compromises the cardio-protective effects of metformin. In summary, this study indicated that MetS promotes cardiac ferroptosis, and metformin plays a preventive and therapeutic role, partially through modulation of Nrf2 expression.

Emerging mechanisms of non-alcoholic steatohepatitis and novel drug therapies

Non-alcoholic fatty liver disease (NAFLD) has become a leading cause of chronic liver disease globally. It initiates with simple steatosis (NAFL) and can progress to the more severe condition of non-alcoholic steatohepatitis (NASH). NASH often advances to end-stage liver diseases such as liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Notably, the transition from NASH to end-stage liver diseases is irreversible, and the precise mechanisms driving this progression are not yet fully understood. Consequently, there is a critical need for the development of effective therapies to arrest or reverse this progression. This review provides a comprehensive overview of the pathogenesis of NASH, examines the current therapeutic targets and pharmacological treatments, and offers insights for future drug discovery and development strategies for NASH therapy.

Exploration and Validation of Ferroptosis-Associated Genes in ADAR1 Deletion-Induced NAFLD through RNA-seq Analysis

BACKGROUND

Ferroptosis, characterized by excessive iron ions and lipid peroxides accumulation, contributes to Nonalcoholic Fatty Liver Disease (NAFLD) development. The role of ADAR1, crucial for lipid metabolism and immune regulation, in ferroptosis-related NAFLD remains unexplored.

METHODS

In this study, we analyzed the expression of ADAR1 in NAFLD patients using the GSE66676 database. Subsequently, We investigated the effects of ADAR1 knockdown on mitochondrial membrane potential (MMP), Fe2+ levels, oxidation products, and ferroptosis in NAFLD cells through in vitro and in vivo experiments. Additionally, RNA-seq analysis was performed following ADAR1 depletion in an NAFLD cell model. Overlapping and ferroptosis-related genes were identified using a Venn diagram, while Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted as well. Furthermore, a protein-protein interaction (PPI) network was constructed to identify hub genes associated with ferroptosis.

RESULTS

We found the expression level of ADAR1 was downregulated in NAFLD patients and 22 ferroptosis-associated genes were differentially expressed in a NAFLD cell model upon ADAR1 knockdown. Based on PPI network, we identified NOS2, PTGS2, NOX4, ALB, IL6, and CCL5 as the central genes related to ferroptosis. ADAR1 deletion-related NAFLD was found to be involved in the ferroptosis signaling pathway. NOS2, PTGS2, ALB, and IL6 can serve as potential biomarkers. These findings offer new insights and expanded targets for NAFLD prevention and treatment.

CONCLUSION

These findings provide new strategies and potential targets for preventing and treating NAFLD. NOS2, PTGS2, ALB, and IL6 may serve as biomarkers for ADAR1 deletion-related NAFLD, which could help for developing its new diagnostic and therapeutic strategies.

Emerging role of regulated cell death in intestinal failure-associated liver disease

Intestinal failure-associated liver disease (IFALD) is a common complication of long-term parenteral nutrition that is associated with significant morbidity and mortality. It is mainly characterized by cholestasis in children and steatohepatitis in adults. Unfortunately, there is no effective approach to prevent or reverse the disease. Regulated cell death (RCD) represents a fundamental biological paradigm that determines the outcome of a variety of liver diseases. Nowadays cell death is reclassified into several types, based on the mechanisms and morphological phenotypes. Emerging evidence has linked different modes of RCD, such as apoptosis, necroptosis, ferroptosis, and pyroptosis to the pathogenesis of liver diseases. Recent studies have shown that different modes of RCD are present in animal models and patients with IFALD. Understanding the pathogenic roles of cell death may help uncover the underlying mechanisms and develop novel therapeutic strategies in IFALD. In this review, we discuss the current knowledge on how RCD may link to the pathogenesis of IFALD. We highlight examples of cell death-targeted interventions aiming to attenuate the disease, and provide perspectives for future basic and translational research in the field.

Examining the Pathogenesis of MAFLD and the Medicinal Properties of Natural Products from a Metabolic Perspective

Metabolic-associated fatty liver disease (MAFLD), characterized primarily by hepatic steatosis, has become the most prevalent liver disease worldwide, affecting approximately two-fifths of the global population. The pathogenesis of MAFLD is extremely complex, and to date, there are no approved therapeutic drugs for clinical use. Considerable evidence indicates that various metabolic disorders play a pivotal role in the progression of MAFLD, including lipids, carbohydrates, amino acids, and micronutrients. In recent years, the medicinal properties of natural products have attracted widespread attention, and numerous studies have reported their efficacy in ameliorating metabolic disorders and subsequently alleviating MAFLD. This review aims to summarize the metabolic-associated pathological mechanisms of MAFLD, as well as the natural products that regulate metabolic pathways to alleviate MAFLD.

MAFLD as part of systemic metabolic dysregulation

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. In recent years, a new terminology and definition of metabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed. Compared to the NAFLD definition, MAFLD better emphasizes the pathogenic role of metabolic dysfunction in the development and progression of this highly prevalent condition. Metabolic disorders, including overweight/obesity, type 2 diabetes mellitus (T2DM), atherogenic dyslipidemia and hypertension, are often associated with systemic organ dysfunctions, thereby suggesting that multiple organ damage can occur in MAFLD. Substantial epidemiological evidence indicates that MAFLD is not only associated with an increased risk of liver-related complications, but also increases the risk of developing several extra-hepatic diseases, including new-onset T2DM, adverse cardiovascular and renal outcomes, and some common endocrine diseases. We have summarized the current literature on the adverse effect of MAFLD on the development of multiple extrahepatic (cardiometabolic and endocrine) complications and examined the role of different metabolic pathways and organ systems in the progression of MAFLD, thus providing new insights into the role of MAFLD as a multisystem metabolic disorder. Our narrative review aimed to provide insights into potential mechanisms underlying the known associations between MAFLD and extrahepatic diseases, as part of MAFLD as a multisystem disease, in order to help focus areas for future drug development targeting not only liver disease but also the risk of extrahepatic complications.

STING deficiency alleviates ferroptosis through FPN1 stabilization in diabetic kidney disease

Ferroptosis, a form of cell death driven by iron-dependent lipid peroxidation, has known as one of the most significant pathological processes involved in diabetic kidney disease (DKD). Stimulator of interferon genes (STING) has been demonstrated its potential in regulating ferroptosis, but the regulatory role in DKD mice and underlying mechanisms haven't been illustrated. To elucidate whether and how STING regulates ferroptosis in DKD, we detected the influence of STING on diabetic-related ferroptosis in a diabetic model and in erastin-induced renal tubular epithelial cells (RTECs). Our study demonstrated that STING was abnormally activated and promoted ferroptosis in DKD. STING deficiency alleviated renal pathologic damages and disfunction in diabetic mice via alleviating ferroptosis and reducing oxidative stress. Mechanismly, STING inhibition was shown to improve ferroptosis and reduce oxidative stress in erastin-induced RTECs. The disruption of ferroportin1 (FPN1) on the basis of STING inhibition abolished the improvements in ferroptosis and promoted reactive oxygen species (ROS) generation. Further, STING inhibition alleviated ferroptosis via stabilizing FPN1 protein level by decreasing ubiquitinated FPN1 for proteasomal degradation. In conclusion, STING deficiency protected against diabetic renal injury via alleviating ferroptosis through stabilizing FPN1 and reducing oxidative stress, providing a possible potential approach for the treatment of DKD.

Underlying Mechanisms behind the Brain-Gut-Liver Axis and Metabolic-Associated Fatty Liver Disease (MAFLD): An Update

Metabolic-associated fatty liver disease (MAFLD) includes several metabolic dysfunctions caused by dysregulation in the brain-gut-liver axis and, consequently, increases cardiovascular risks and fatty liver dysfunction. In MAFLD, type 2 diabetes mellitus, obesity, and metabolic syndrome are frequently present; these conditions are related to liver lipogenesis and systemic inflammation. This study aimed to review the connection between the brain-gut-liver axis and MAFLD. The inflammatory process, cellular alterations in hepatocytes and stellate cells, hypercaloric diet, and sedentarism aggravate the prognosis of patients with MAFLD. Thus, to understand the modulation of the physiopathology of MAFLD, it is necessary to include the organokines involved in this process (adipokines, myokines, osteokines, and hepatokines) and their clinical relevance to project future perspectives of this condition and bring to light new possibilities in therapeutic approaches. Adipokines are responsible for the activation of distinct cellular signaling in different tissues, such as insulin and pro-inflammatory cytokines, which is important for balancing substances to avoid MAFLD and its progression. Myokines improve the quantity and quality of adipose tissues, contributing to avoiding the development of MAFLD. Finally, hepatokines are decisive in improving or not improving the progression of this disease through the regulation of pro-inflammatory and anti-inflammatory organokines.

Mechanisms of ferroptosis in nonalcoholic fatty liver disease and therapeutic effects of traditional Chinese medicine: a review

Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive accumulation of fat in hepatocytes (nonalcoholic fatty liver (NAFL)), and lobular inflammation and hepatocyte damage (which characterize nonalcoholic steatohepatitis (NASH) are found in most patients). A subset of patients will gradually develop liver fibrosis, cirrhosis, and eventually hepatocellular carcinoma, which is a deadly disease that threatens human life worldwide. Ferroptosis, a novel nonapoptotic form of programmed cell death (PCD) characterized by iron-dependent accumulation of reactive oxygen radicals and lipid peroxides, is closely related to NAFLD. Traditional Chinese medicine (TCM) has unique advantages in the prevention and treatment of NAFLD due to its multicomponent, multipathway and multitarget characteristics. In this review, we discuss the effect of TCM on NAFLD by regulating ferroptosis, in order to provide reference for the further development and application of therapeutic drugs to treat NAFLD.

Topical rhubarb charcoal-crosslinked chitosan/silk fibroin sponge scaffold for the repair of diabetic ulcers improves hepatic lipid deposition in db/db mice via the AMPK signalling pathway

BACKGROUND

Type 2 diabetes mellitus (T2DM) is closely linked to metabolic syndrome, characterised by insulin resistance, hyperglycaemia, abnormal lipid metabolism, and chronic inflammation. Diabetic ulcers (DUs) comprise consequential complications that arise as a result of T2DM. To investigate, db/db mice were used for the disease model. The findings demonstrated that a scaffold made from a combination of rhubarb charcoal-crosslinked chitosan and silk fibroin, designated as RCS/SF, was able to improve the healing process of diabetic wounds in db/db mice. However, previous studies have primarily concentrated on investigating the impacts of the RSC/SF scaffold on wound healing only, while its influence on the entire body has not been fully elucidated.

MATERIAL AND METHODS

The silk fibroin/chitosan sponge scaffold containing rhubarb charcoal was fabricated in the present study using a freeze-drying approach. Subsequently, an incision with a diameter of 8 mm was made on the dorsal skin of the mice, and the RCS/SF scaffold was applied directly to the wound for 14 days. Subsequently, the impact of RCS/SF scaffold therapy on hepatic lipid metabolism was assessed through analysis of serum and liver biochemistry, histopathology, quantitative real-time PCR (qRT-PCR), immunohistochemistry, and Western blotting.

RESULTS

The use of the RCS/SF scaffold led to an enhancement in the conditions associated with serum glucolipid metabolism in db/db mice. An assessment of hepatic histopathology further confirmed this enhancement. Additionally, the qRT-PCR analysis revealed that treatment with RCS/SF scaffold resulted in the downregulation of genes associated with fatty acid synthesis, fatty acid uptake, triglyceride (TG) synthesis, gluconeogenesis, and inflammatory factors. Moreover, the beneficial effect of the RCS/SF scaffold on oxidative stress was shown by assessing antioxidant enzymes and lipid peroxidation. Additionally, the network pharmacology analysis verified that the adenosine monophosphate-activated protein kinase (AMPK) signalling pathway had a vital function in mitigating non-alcoholic fatty liver disease (NAFLD) by utilizing R. officinale. The measurement of AMPK, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthase (FASN), and acetyl CoA carboxylase (ACC) gene and protein expression provided support for this discovery. Furthermore, the molecular docking investigations revealed a robust affinity between the active components of rhubarb and the downstream targets of AMPK (SREBP1 and FASN).

CONCLUSION

By regulating the AMPK signalling pathway, the RCS/SF scaffold applied topically effectively mitigated hepatic lipid accumulation, decreased inflammation, and attenuated oxidative stress. The present study, therefore, emphasises the crucial role of the topical RCS/SF scaffold in regulating hepatic lipid metabolism, thereby confirming the concept of "external and internal reshaping".

Iron, Oxidative Stress, and Metabolic Dysfunction-Associated Steatotic Liver Disease

Excess free iron is a substrate for the formation of reactive oxygen species (ROS), thereby augmenting oxidative stress. Oxidative stress is a well-established cause of organ damage in the liver, the main site of iron storage. Ferroptosis, an iron-dependent mechanism of regulated cell death, has recently been gaining attention in the development of organ damage and the progression of liver disease. We therefore summarize the main mechanisms of iron metabolism, its close connection to oxidative stress and ferroptosis, and its particular relevance to disease mechanisms in metabolic-dysfunction-associated fatty liver disease and potential targets for therapy from a clinical perspective.

Sodium Butyrate Alleviates Free Fatty Acid-Induced Steatosis in Primary Chicken Hepatocytes via Regulating the ROS/GPX4/Ferroptosis Pathway

Fatty liver hemorrhagic syndrome (FLHS) in laying hens is a nutritional metabolic disease commonly observed in high-yielding laying hens. Sodium butyrate (NaB) and ferroptosis were reported to contribute to the pathogenesis of fatty liver-related diseases. However, the underlying mechanism of NaB in FLHS and whether it mediates ferroptosis remains unclear. A chicken primary hepatocyte induced by free fatty acids (FFAs, keeping the ratio of sodium oleate and sodium palmitate concentrations at 2:1) was established, which received treatments with NaB, the ferroptosis inducer RAS-selective lethal 3 (RSL3), and the inhibitor ferrostatin-1 (Fer-1). As a result, NaB increased biochemical and lipid metabolism indices, and the antioxidant level, while inhibiting intracellular ROS accumulation and the activation of the ferroptosis signaling pathway, as evidenced by a reduction in intracellular iron concentration, upregulated GPX4 and xCT expression, and inhibited NCOA4 and ACSL4 expression. Furthermore, treatment with Fer-1 reinforced the protective effects of NaB, while RSL3 reversed it by blocking the ROS/GPX4/ferroptosis pathway, leading to the accumulation of lipid droplets and oxidative stress. Collectively, our findings demonstrated that NaB protects hepatocytes by regulating the ROS/GPX4-mediated ferroptosis pathway, providing a new strategy and target for the treatment of FLHS.

Pharmacological therapy of metabolic dysfunction-associated steatotic liver disease-driven hepatocellular carcinoma

In light of a global rise in the number of patients with type 2 diabetes mellitus (T2DM) and obesity, non-alcoholic fatty liver disease (NAFLD), now known as metabolic dysfunction-associated fatty liver disease (MAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD), has become the leading cause of hepatocellular carcinoma (HCC), with the annual occurrence of MASLD-driven HCC expected to increase by 45%-130% by 2030. Although MASLD has become a serious major public health threat globally, the exact molecular mechanisms mediating MASLD-driven HCC remain an open problem, necessitating future investigation. Meanwhile, emerging studies are focusing on the utility of bioactive compounds to halt the progression of MASLD to MASLD-driven HCC. In this review, we first briefly review the recent progress of the possible mechanisms of pathogenesis and progression for MASLD-driven HCC. We then discuss the application of bioactive compounds to mitigate MASLD-driven HCC through different modulatory mechanisms encompassing anti-inflammatory, lipid metabolic, and gut microbial pathways, providing valuable information for future treatment and prevention of MASLD-driven HCC. Nonetheless, clinical research exploring the effectiveness of herbal medicines in the treatment of MASLD-driven HCC is still warranted.

Chinese herbal medicines: The modulator of nonalcoholic fatty liver disease targeting oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Plants are a natural treasure trove; their secondary metabolites participate in several pharmacological processes, making them a crucial component in the synthesis of novel pharmaceuticals and serving as a reserve resource foundation in this process. Nonalcoholic fatty liver disease (NAFLD) is associated with the risk of progression to hepatitis and liver cancer. The "Treatise on Febrile Diseases," "Compendium of Materia Medica," and "Thousand Golden Prescriptions" have listed herbal remedies to treat liver diseases.

AIM OF THE REVIEW

Chinese herbal medicines have been widely used for the prevention and treatment of NAFLD owing to their efficacy and low side effects. The production of reactive oxygen species (ROS) during NAFLD, and the impact and potential mechanism of ROS on the pathogenesis of NAFLD are discussed in this review. Furthermore, common foods and herbs that can be used to prevent NAFLD, as well as the structure-activity relationships and potential mechanisms, are discussed.

METHODS

Web of Science, PubMed, CNKI database, Google Scholar, and WanFang database were searched for natural products that have been used to treat or prevent NAFLD in the past five years. The primary search was performed using the following keywords in different combinations in full articles: NAFLD, herb, natural products, medicine, and ROS. More than 400 research papers and review articles were found and analyzed in this review.

RESULTS

By classifying and discussing the literature, we obtained 86 herbaceous plants, 28 of which were derived from food and 58 from Chinese herbal medicines. The mechanism of NAFLD was proposed through experimental studies on thirteen natural compounds (quercetin, hesperidin, rutin, curcumin, resveratrol, epigallocatechin-3-gallate, salvianolic acid B, paeoniflorin, ginsenoside Rg1, ursolic acid, berberine, honokiol, emodin). The occurrence and progression of NAFLD could be prevented by natural antioxidants through several pathways to prevent ROS accumulation and reduce hepatic cell injuries caused by excessive ROS.

CONCLUSION

This review summarizes the natural products and routinely used herbs (prescription) in the prevention and treatment of NAFLD. Firstly, the mechanisms by which natural products improve NAFLD through antioxidant pathways are elucidated. Secondly, the potential of traditional Chinese medicine theory in improving NAFLD is discussed, highlighting the safety of food-medicine homology and the broader clinical potential of multi-component formulations in improving NAFLD. Aiming to provide theoretical basis for the prevention and treatment of NAFLD.

Different types of cell death in diabetic endothelial dysfunction

Diabetes mellitus is a metabolic disease caused by disorders of insulin secretion and utilization. Long-term hyperglycemia, insulin resistance, and disorders of glucose and lipid metabolism cause vascular endothelial cell damage. Endothelial dysfunction is a key feature of diabetic vascular complications such as diabetic nephropathy, retinopathy, neuropathy, and atherosclerosis. Importantly, cell death is thought to be a key factor contributing to vascular endothelial injury. Morphologically, cell death can be divided into three forms: type I apoptosis, type II autophagy, and type III necrosis. According to the difference in function, cell death can be divided into accidental cell death (ACD) and regulated cell death (RCD). RCD is a controlled process involving numerous proteins and precise signaling cascades. Multiple subroutines covered by RCD may be involved in diabetic endothelial dysfunction, including apoptosis, autophagy, necroptosis, pyroptosis, entosis, ferroptosis, ferroautophagy, parthanatos, netotic cell death, lysosome-dependent cell death, alkaliptosis, oxeiptosis, cuproptosis, and PANoptosis. This article briefly reviews the mechanism and significance of cell death associated with diabetic endothelial dysfunction, which will help deepen the understanding of diabetic endothelial cell death and provide new therapeutic ideas.

Puerarin ameliorates metabolic dysfunction-associated fatty liver disease by inhibiting ferroptosis and inflammation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is frequently linked to type 2 diabetes mellitus (T2DM), and both conditions exacerbate the progression of the other. However, there is currently no standardized treatment or drug for MAFLD. In this study, A MAFLD animal model through a high-fat diet (HFD) along with administration of streptozotocin (STZ), and palmitic acid (PA)-induced AML12 cells were treated by puerarin. The objective of this study was to assess the therapeutic effect of puerarin, a flavonoid substance that possesses various pharmacological properties, on MAFLD. The results showed that puerarin administration enhanced glucose tolerance and insulin sensitivity, while also mitigating liver dysfunction and hyperlipidemia in MAFLD mice. Moreover, puerarin attenuated oxidative stress levels and inflammation in the liver. Transmission electron microscopy and Western blot analysis indicated that puerarin inhibited ferroptosis in vivo. Further mechanistic investigations revealed that puerarin upregulated SIRT1 expression, increased nuclear factor erythroid 2-related factor 2 (Nrf2) protein levels, and facilitated translocation into the nucleus. The protective effect of puerarin on PA-induced AML12 cells was diminished by the utilization of EX-527 (a SIRT1 inhibitor) and Nrf2 siRNA. Overall, the results demonstrate that puerarin ameliorates MAFLD by suppressing ferroptosis and inflammation via the SIRT1/Nrf2 signaling pathway. The results emphasize the possible medicinal application of puerarin for managing MAFLD.

Use of a ferroptosis-related gene signature to construct diagnostic and prognostic models for assessing immune infiltration in metabolic dysfunction-associated fatty liver disease

Introduction: Metabolic dysfunction-associated fatty liver disease (MAFLD), a serious health problem worldwide, can involve ferroptosis. This study aimed to comprehensively analyze the ferroptosis-related genes associated with MAFLD. Methods: Ferroptosis-related differentially expressed genes (FRDEGs) were identified in patients with MAFLD and healthy individuals. Gene ontology functional enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and gene set enrichment analysis (GSEA) were used to analyze the relevant action pathways of the FRDEGs. The Encyclopedia of RNA Interactomes, CHIPBase, and comparative toxicogenomics databases were used to build mRNA-miRNA, mRNA-transcription factor (TF), and mRNA-drug interaction networks, respectively. A diagnostic model was constructed and bioinformatics analysis methods, such as least absolute shrinkage and selection operator regression analysis, Cox regression analysis, nomogram-based analysis, consensus clustering analysis, and single-sample GSEA, were used to systematically investigate the prognostic values and immunologic characteristics. Results: A total of 13 FRDEGs were obtained and eight were used to construct a diagnostic model and perform a prognostic analysis. Hub genes were also used to construct mRNA-miRNA and mRNA-TF interaction networks and potential drug or molecular compounds. Two MAFLD subtypes were identified: cluster2, which represents an "immunoactive" type, and cluster1, which represents an "immunosuppressive" type; a significant correlation was observed between the immune cell contents and the expression of three FRDEGs (NR4A1, FADS2, and SCD). Conclusion: A ferroptosis-related gene signature was constructed to diagnose MAFLD-associated steatohepatitis, predict the prognosis of MAFLD patients, and analyze the immunologic characteristics of MAFLD. Our findings may provide insights into developing innovative MAFLD treatment techniques.

Three-Dimensional Regulation of Ferroptosis at the Intersection of Iron, Sulfur, and Oxygen Executing Scrap and Build Toward Evolution

Significance: Iron is an essential element for every life on earth as a primary media for electron flow. Sulfur compounds as sulfhydryls counteract catalytic activity of iron whereas sulfur overdose is also toxic. In aerobic organisms, oxygen is the major media for electron transfer with higher intracellular mobility, which cooperates with the iron system. Based on the importance of iron, there is no active pathway to excrete iron outside the body in higher species. Whereas bacterial infection causes a scramble for iron in situ, cancer can be the outcome of the side effects of long use of iron and oxygen. Recent Advances: Ferroptosis is a recently coined cell death, defined as catalytic Fe(II)-dependent regulated necrosis accompanied by lipid peroxidation. Researchers recently recognized that ferroptosis is involved in a variety of physiological and pathological contexts, including embryonic erythropoiesis, aging, neurodegeneration and cancer cell death. Alternatively, carcinogenesis is a process to obtain iron addiction with ferroptosis-resistance, based on rodent animal studies. Critical Issues: Here we propose that ferroptosis is three-dimensionally regulated by iron, sulfur and oxygen, which correspond to oxidants, antioxidants and membrane fluidity with susceptibility to lipid peroxidation, respectively. Future Directions: Whereas life attempts to prevent ferroptosis, ferroptotic cells eventually emit iron-loaded ferritin as extracellular vesicles to maintain monopoly of iron. Antioxid. Redox Signal. 39, 807-815.

Liraglutide attenuates type 2 diabetes mellitus-associated non-alcoholic fatty liver disease by activating AMPK/ACC signaling and inhibiting ferroptosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is one of the most common complications of type 2 diabetes mellitus (T2DM). The pathogenesis of NAFLD involves multiple biological changes, including insulin resistance, oxidative stress, inflammation, as well as genetic and environmental factors. Liraglutide has been used to control blood sugar. But the impact of liraglutide on T2DM-associated NAFLD remains unclear. In this study, we investigated the impact and potential molecular mechanisms of inhibiting ferroptosis for liraglutide improves T2DM-associated NAFLD.

METHODS

Mice were fed on high-fat-diet and injected with streptozotocin to mimic T2DM-associated NAFLD and gene expression in liver was analysed by RNA-seq. The fast blood glucose was measured during the period of liraglutide and ferrostatin-1 administration. Hematoxylin and eosin staining was used to evaluate the pathological changes in the liver. The occurrence of hepatic ferroptosis was measured by lipid peroxidation in vivo. The mechanism of liraglutide inhibition ferroptosis was investigated by in vitro cell culture.

RESULTS

Liraglutide not only improved glucose metabolism, but also ameliorated tissue damage in the livers. Transcriptomic analysis indicated that liraglutide regulates lipid metabolism related signaling including AMPK and ACC. Furthermore, ferroptosis inhibitor rather than other cell death inhibitors rescued liver cell viability in the presence of high glucose. Mechanistically, liraglutide-induced activation of AMPK phosphorylated ACC, while AMPK inhibitor compound C blocked the liraglutide-mediated suppression of ferroptosis. Moreover, ferroptosis inhibitor restored liver function in T2DM mice in vivo.

CONCLUSIONS

These findings indicate that liraglutide ameliorates the T2DM-associated NAFLD, which possibly through the activation of AMPK/ACC pathway and inhibition of ferroptosis.

Trends and hotspots of publications on ferroptosis: A 10 Year overview

Background

Ferroptosis was proposed to be a type of programmed cell death in 2012. Ferroptosis plays a significant role in a variety of illnesses.

Objective

To better understand the direction of future research, we performed a bibliometric analysis to identify research hotspots with a focus on ferroptosis.

Methods

The search terms [TI = "ferroptosis" OR ("GSH" AND "GPX4") OR "lipid peroxidation" OR "iron homeostasis" OR "iron metabolism"] AND [PY = "2012-2022"] AND [DT = "Article OR Review"] AND [LA = "English"] were used to retrieve publications related to ferroptosis for a bibliometric analysis. We utilized Microsoft Excel to calculate the frequency and proportion of the published articles, VOSviewer to perform a co-occurrence analysis and for visualizing the data, CiteSpace to obtain a timeline of keywords and institutions, and RStudio to calculate citation metrics. As indicated by the analysis, indicators such as the number of publications, the most productive authors and coauthorship status, the distribution of publications by country, favoured journals, the most influential institutions and the most frequently cited documents are reported in this article.

Results

A total of 8009 publications were retrieved from the WOS core collection, and 197 papers published in 2023 were removed from this analysis. The remaining 7812 papers, which included 118 in the WOS collection, were incorporated into the bibliometric study.

Conclusion

The number of annual scientific publications on ferroptosis have been increasing each year. The academic communities represented by Tang, Daolin, Stockwell, Brent R., Wang, Fudi, and Conrad, Marcus were the most authoritative. China, USA, and Germany were the front-runners in the field of ferroptosis. Free Radical Biology and Medicine was the largest contributor of ferroptosis-related research, and Cell and Nature were the most influential journals to publish articles on ferroptosis. Columbia Univ and Univ Pittsburgh were the institutions that received the most attention. Recent research on ferroptosis has been focused on molecular mechanisms, particularly those in the contexts of various diseases, which will be a hotspot of future research. In addition, interdisciplinary ferroptosis and big-data research is expected to be a new frontier.

Evaluation of the Effects of Chia (Salvia hispanica L.) Leaves Ethanolic Extracts Supplementation on Biochemical and Hepatic Markers on Diet-Induced Obese Mice

Obesity is a significant health concern affecting 13% of the world's population. It is often associated with insulin resistance and metabolic-associated fatty liver disease (MAFLD), which can cause chronic inflammation in the liver and adipose tissue. Obese hepatocytes show increased lipid droplets and lipid peroxidation, which can lead to the progression of liver damage. Polyphenols have been shown to have the ability to reduce lipid peroxidation, thereby promoting hepatocyte health. Chia leaves, a by-product of chia seed production, are a natural source of bioactive antioxidant compounds, such as cinnamic acids and flavonoids, which have antioxidant and anti-inflammatory properties. In this study, chia leaves' ethanolic extracts of two seed phenotypes were tested on diet-induced obese mice to evaluate their therapeutic potential. Results show that the chia leaf extract positively affected insulin resistance and lipid peroxidation in the liver. In addition, the extract improved the HOMA-IR index compared to the obese control group, reducing the number and size of lipid droplets and lipid peroxidation. These results suggest that chia leaf extract may help treat insulin resistance and liver damage associated with MAFLD.

Activation of Kupffer cells in NAFLD and NASH: mechanisms and therapeutic interventions

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are emerging as the leading causes of liver disease worldwide. These conditions can lead to cirrhosis, liver cancer, liver failure, and other related ailments. At present, liver transplantation remains the sole treatment option for end-stage NASH, leading to a rapidly growing socioeconomic burden. Kupffer cells (KCs) are a dominant population of macrophages that reside in the liver, playing a crucial role in innate immunity. Their primary function includes phagocytosing exogenous substances, presenting antigens, and triggering immune responses. Moreover, they interact with other liver cells during the pathogenesis of NAFLD, and this crosstalk may either delay or exacerbate disease progression. Stimulation by endogenous signals triggers the activation of KCs, resulting in the expression of various inflammatory factors and chemokines, such as NLRP3, TNF-α, IL-1B, and IL-6, and contributing to the inflammatory cascade. In the past 5 years, significant advances have been made in understanding the biological properties and immune functions of KCs in NAFLD, including their interactions with tissue molecules, underlying molecular mechanisms, signaling pathways, and relevant therapeutic interventions. Having a comprehensive understanding of these mechanisms and characteristics can have enormous potential in guiding future strategies for the prevention and treatment of NAFLD.

Ferroptosis in non-alcoholic liver disease: Molecular mechanisms and therapeutic implications

Ferroptosis refers to a novel modality of regulated cell death characterized by excessive iron accumulation and overwhelming lipid peroxidation, which takes an important part in multiple pathological processes associated with cell death. Considering the crucial roles of the liver in iron and lipid metabolism and its predisposition to oxidative insults, more and more studies have been conducted to explore the relationship between ferroptosis and various liver disorders, including non-alcoholic fatty liver disease (NAFLD). With increased morbidity and high mortality rates, NAFLD has currently emerged as a global public health issue. However, the etiology of NAFLD is not fully understood. In recent years, an accumulating body of evidence have suggested that ferroptosis plays a pivotal role in the pathogenesis of NAFLD, but the precise mechanisms underlying how ferroptosis affects NAFLD still remain obscure. Here, we summarize the molecular mechanisms of ferroptosis and its complicated regulation systems, delineate the different effects that ferroptosis exerts in different stages of NAFLD, and discuss some potential effective therapies targeting ferroptosis for NAFLD treatment, which putatively points out a novel direction for NAFLD treatment.

The Emerging Role of Ferroptosis in Various Chronic Liver Diseases: Opportunity or Challenge

Ferroptosis is a recently identified iron-dependent form of intracellular lipid peroxide accumulation-mediated cell death. Different from other types of cell death mechanisms, it exhibits distinct biological and morphological features characterized by the loss of lipid peroxidase repair activity caused by glutathione peroxidase 4, the presence of redox-active iron, and the oxidation of phospholipids-containing polyunsaturated fatty acids. In recent years, studies have shown that ferroptosis plays a key role in various liver diseases such as alcoholic liver injury, non-alcoholic steatohepatitis, liver cirrhosis, and liver cancer. However, the mechanism of ferroptosis and its regulation on chronic liver disease are controversial among different types of cells in the liver. Herein, we summarize the current studies on mechanism of ferroptosis in chronic liver disease, aiming to outline the blueprint of ferroptosis as an effective option for chronic liver disease therapy.

Causal relationships between metabolic-associated fatty liver disease and iron status: Two-sample Mendelian randomization

BACKGROUND & AIMS

Dysregulated iron homeostasis plays an important role in the hepatic manifestation of metabolic-associated fatty liver disease (MAFLD). We investigated the causal effects of five iron metabolism markers, regular iron supplementation and MAFLD risk.

METHODS

Genetic summary statistics were obtained from open genome-wide association study databases. Two-sample bidirectional Mendelian randomization analysis was performed to estimate the causal effect between iron status and MAFLD, including Mendelian randomization inverse-variance weighted, weighted median methods and Mendelian randomization-Egger regression. The Mendelian randomization-PRESSO outlier test, Cochran's Q test and Mendelian randomization-Egger regression were used to assess outliers, heterogeneity and pleiotropy respectively.

RESULTS

Mendelian randomization inverse-variance weighted results showed that the genetically predicted per standard deviation increase in liver iron (Data set 2: odds ratio 1.193, 95% confidence interval [CI] 1.074-1.326, p = .001) was associated with an increased MAFLD risk, consistent with the weighted median estimates and Mendelian randomization-Egger regression, although Data set 1 was not significant. Mendelian randomization inverse-variance weighted analysis showed that genetically predicted MAFLD was significantly associated with increased serum ferritin levels in both datasets (Dataset 1: β = .038, 95% CI = .014 to .062, p = .002; Dataset 2: β = .081, 95% CI = .025 to .136, p = .004), and a similar result was observed with the weighted median methods for Dataset 2 instead of Mendelian randomization-Egger regression.

CONCLUSIONS

This study uncovered genetically predicted causal associations between iron metabolism status and MAFLD. These findings underscore the need for improved guidelines for managing MAFLD risk by emphasizing hepatic iron levels as a risk factor and ferritin levels as a prognostic factor.

The Role of STAMP2 in Pathogenesis of Chronic Diseases Focusing on Nonalcoholic Fatty Liver Disease: A Review

Nonalcoholic fatty liver disease (NAFLD) is a major health issue. NAFLD can progress from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH). NASH can progress to cirrhosis or hepatocellular carcinoma. Unfortunately, there is no currently approved pharmacologic therapy for NAFLD patients. The six transmembrane protein of prostate 2 (STAMP2), a metalloreductase involved in iron and copper homeostasis, is well known for its critical role in the coordination of glucose/lipid metabolism and inflammation in metabolic tissues. We previously demonstrated that hepatic STAMP2 could be a suitable therapeutic target for NAFLD. In this review, we discuss the emerging role of STAMP2 in the dysregulation of iron metabolism events leading to NAFLD and suggest therapeutic strategies targeting STAMP2.