Ferroptosis as an emerging therapeutic target in liver diseases

Mechanistic evaluation of a traditional herbal decoction in attenuating hepatic fibrosis via Nrf2/GPX4 pathway activation and ferroptosis inhibition

BACKGROUND

Hepatic fibrosis, a progressive fibrotic response to chronic liver injury, is characterized by excessive collagen deposition and impaired tissue repair. This pathological process leads to liver dysfunction and potential progression to irreversible cirrhosis or hepatocellular carcinoma. Currently, therapeutic options targeting the underlying mechanisms remain limited. Traditional Chinese medicine (TCM), particularly herbal decoctions, have demonstrated efficacy in the treatment of hepatic fibrosis, although the precise mechanisms remain insufficiently elucidated.

OBJECTIVE

The objective of this study is to examine the mechanistic role of a TCM herbal decoction designed to promote Qi, blood circulation, and water excretion, in modulating the Nrf2/GPX4 signaling pathway and inhibiting ferroptosis in a rat model of hepatic fibrosis.

METHODS

A total of 17 Sprague-Dawley rats were divided into five groups. The blank control group (Group A) comprised three rats. Hepatic fibrosis was induced in the remaining rats, which were then randomized into four groups: the untreated fibrosis (Group B), TCM-treated (Group C), TCM combined with ferroptosis inhibitor (Fer-1) (Group D), and TCM combined with Fer-1 and autophagy inhibitor (3-MA) (Group E). Groups A and B received equal volumes of normal saline. Serum and hepatic tissues were collected for analysis. Serum levels of aspartate transaminase (AST), alanine aminotransferase (ALT), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), and iron were measured. Liver tissues were subjected to hematoxylin and eosin staining and Masson's trichrome staining to assess pathological changes. Protein expression levels of solute carrier family 7 member 11 (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione peroxidase 4 (GPX4) were assessed using western blot analysis.

RESULTS

Group B exhibited significant deterioration compared to the control group (p < 0.05), including marked hepatic lipidosis and fibrosis surrounding the hepatic portal vein. Elevated levels of AST, ALT, Fe2+, MDA, TNF-α, and collagen volume were observed (p < 0.05), along with significantly reduced expression of GPX4, Nrf2, and SLC7A11 (p < 0.05). In contrast, Groups C, D, and E demonstrated significantly decreased levels of AST, ALT, Fe2+, MDA, TNF-α, and collagen volume (p < 0.05), accompanied by increased expression of GPX4, Nrf2, and SLC7A11 (p < 0.05) when compared to Group B.

CONCLUSION

The herbal decoction demonstrated anti-fibrotic effects in a rat model of hepatic fibrosis, potentially through activation of the Nrf2/GPX4 signaling pathway and suppression of ferroptosis. These findings suggest a mechanistic basis for the observed efficacy of this TCM formulation and support its potential as a therapeutic candidate for hepatic fibrosis.

Potential Biomarkers and Therapeutic Targets in Hepatitis B Virus-related Acute Liver Failure: Interplay of the Ferroptosis, Autophagy and Immune Responses

Hepatitis B virus-related acute liver failure (HBV-ALF) is characterized by a high fatality rate, its pathogenesis remains unclear and the therapeutic efficacy is limited. Ferroptosis which closely related to autophagy may be an underlying mechanism of HBV-ALF. The aim of this study was to identify key ferroptosis- and autophagy-related genes and pathways and provide insight into potential therapeutic approaches for HBV-ALF. We accessed the GSE14668 and GSE96851 datasets from the Gene Expression Omnibus (GEO) database and focused on differentially expressed genes (DEGs), ferroptosis-related DEGs (FRGs) and autophagy-related DEGs (ARGs). Hub genes were subsequently analyzed for enrichment, protein‒protein interactions (PPIs), and different immunological microenvironments, and potential hub gene were identified using MCC method and LASSO. Gene-targeted drugs were from the DGIdb and DrugBank databases.A total of 1462 DEGs were identified (726 upregulated and 736 downregulated). Enriched pathways included amino acid metabolism and immune and inflammatory responses, potentially serving as biomarkers for ALF pathogenesis. After integration with the FerrDb and HADb databases, 55 FRGs and 45 ARGs were identified. Thirteen hub genes (SLC7A11, HMOX1, G6PD, RRM2, KIF20A, HELLS, GPT2, GLS2, SPP1, CCR2, DCN, IRS1, and IGF1) were identified which closely associated with the immune microenvironment. Interplay among these genes occurred primarily through HMOX1. Moreover, we identified several hub gene-targeted drugs that may be effective in HBV-ALF treatment, such as riluzole, acetylcysteine, NADH and Vitamin E.Thirteen hub genes may play crucial roles in HBV-ALF progression, particularly, the HMOX1. Furthermore, drug target exploration offered promising avenues for therapeutic intervention in patients with HBV-ALF.

Live and let die: analyzing ultrastructural features in cell death

Cell death is an important process that supports morphogenesis during development and tissue homeostasis during adult life by removing damaged or unwanted cells and its dysregulation is associated with numerous disease states. There are different pathways through which a cell can undergo cell death, each relying on peculiar molecular mechanisms and morpho-ultrastructural features. To date, however, while molecular and genetic approaches have been successfully integrated into the field, cell death studies rarely incorporate ultrastructural data from electron microscopy. This review article reports a gallery of original transmission electron microscopy images to describe the ultrastructural features of cells undergoing different types of cell death programs, including necrosis, apoptosis, autophagy, mitotic catastrophe, ferroptosis, methuosis, and paraptosis. TEM has been an important technology in cell biology for well over 50 years and still continues to offer significant advantages in the area of cell death research. TEM allows detailed characterization of the ultrastructural changes within the cell, such as the alteration of organelles and subcellular structures, the nuclear reorganization, and the loss of membrane integrity that enable a distinction between the different forms of cell death based on morphological criteria. Possible pitfalls are also described.

The role and mechanism of various trace elements in atherosclerosis

Atherosclerosis is a slow and complex disease that involves various factors, including lipid metabolism disorders, oxygen-free radical production, inflammatory cell infiltration, platelet adhesion and aggregation, and local thrombosis. Trace elements play a crucial role in human health. Many trace elements, especially metallic ones, not only maintain the normal functions of organs but also participate in basic metabolic processes. The latest studies have revealed a close correlation between trace elements and the occurrence and progression of atherosclerosis. The imbalance of these trace elements can induce atherosclerosis or accelerate its progression through various mechanisms, which poses a significant threat to human health. Therefore, exploring the specific mechanism of trace elements on atherosclerosis is highly significant. In this review, we summarized the roles and mechanisms of iron, copper, zinc, magnesium, and selenium homeostasis and imbalance in atherosclerosis development, in order to identify novel targets and therapeutic strategies for treating atherosclerosis.

Protocatechuic acid relieves ferroptosis in hepatic lipotoxicity and steatosis via regulating NRF2 signaling pathway

Ferroptosis represents a newly programmed cell death, and the process is usually accompanied with iron-dependent lipid peroxidation. Importantly, ferroptosis is implicated in a myriad of diseases. Recent literature suggests a potential position of ferroptosis in the pathogenesis of metabolic dysfunction-associated fatty liver disease (MAFLD), the most widespread liver ailment worldwide. Intriguingly, several functional genes and metabolic pathways central to ferroptosis are regulated by nuclear factor erythroid-derived 2-like 2 (NRF2). In current work, we aim to identify protocatechuic acid (PCA), a primary metabolite of antioxidant polyphenols, as a potent NRF2 activator and ferroptosis inhibitor in the hepatic lipotoxicity and steatosis models. Herein, both NRF2+/+ and NRF2-/- cell lines and mice were used to analyze the importance of NRF2 in PCA function, and hepatic lipotoxicity and steatosis models were induced by palmitic acid and high-fat diet respectively. Our results indicated that ferroptosis was mitigated by PCA intervention in hepatic cells. Furthermore, PCA exhibited therapeutic efficacy against ferroptosis, as well as hepatic lipotoxicity and steatosis. The protective role of PCA was predominantly mediated through NRF2 activation, potentially elucidating a pivotal mechanism underlying PCA's therapeutic impact on MAFLD. Additionally, the augmented mitochondrial TCA cycle activity observed in hepatic lipotoxicity and steatosis models was ameliorated by PCA, in part via NRF2-dependent pathways, further bolstering PCA's anti-ferroptosis properties. Collectively, our findings underscore PCA's potential in alleviating hepatic ferroptosis, lipotoxicity and steatosis via inducing activation of NRF2 signaling pathway, offering a promising strategy for the therapy of MAFLD as well as related lipid metabolic disorders.

Transcriptome-Based Revelation of the Effects of Sleep Deprivation on Hepatic Metabolic Rhythms in Tibetan Sheep (Ovis aries)

Sleep deprivation (SD) disrupts circadian rhythms; however, its effects on SD and the mechanisms involved require further investigation. Previous studies on SD were mainly conducted on rodents, such as mice, with few studies on its effects on the liver of large diurnal animals, such as sheep. In this study, we used a Tibetan sheep model for the first time to investigate the effects of SD on the liver by exposing Tibetan sheep (Ovis aries) to 7 days of SD (6 h/day) and performed transcriptome sequencing analysis on liver samples taken at 4 h intervals over 24 h. The results revealed that SD significantly altered the circadian expression of genes and their expression patterns in the liver of Tibetan sheep. Enrichment analysis of the circadian rhythm-altered genes revealed changes in the pathways related to lipid metabolism in the liver. Further evidence from serum markers and gene expression analyses using qualitative real-time polymerase chain reaction and Oil Red O and apoptosis staining indicated that SD leads to abnormal lipid metabolism in the liver, potentially causing liver damage. Therefore, our results suggest that SD disrupts the circadian rhythms of metabolism-related genes in the Tibetan sheep liver, thereby affecting metabolic homeostasis.

Targeting both ferroptosis and pyroptosis may represent potential therapies for acute liver failure

In this editorial, we comment on the article published in the recent issue of the World Journal of Gastroenterology. Acute liver failure (ALF) is a fatal disease that causes uncontrolled massive hepatocyte death and rapid loss of liver function. Ferroptosis and pyroptosis, cell death forms that can be initiated or blocked concurrently, can play significant roles in developing inflammation and various malignancies. However, their roles in ALF remain unclear. The article discovered the positive feedback between ferroptosis and pyroptosis in the progression of ALF, and revealed that the silent information regulator sirtuin 1 (SIRT1) inhibits both pathways through p53, dramatically reducing inflammation and protecting hepatocytes. This suggests the potential use of SIRT1 and its downstream molecules as therapeutics for ALF. Thus, we will discuss the role of ferroptosis and pyroptosis in ALF and the crosstalk between these cell death mechanisms. Additionally, we address potential treatments that could alleviate ALF by simultaneously inhibiting both cell death pathways, as well as examples of SIRT1 activators being used as disease treatment strategies, providing new insights into the therapy of ALF.

Chlorantraniliprole induces mitophagy, ferroptosis, and cytokine homeostasis imbalance in grass carp (Ctenopharyngodon idella) hepatocytes via the mtROS-mitochondrial fission/fusion axis

Chlorantraniliprole (CAP) is a bis-amide pesticide used for pest control mainly in agricultural production activities and rice-fish co-culture systems. CAP residues cause liver damage in non-target organism freshwater fish. However, it is unclear whether CAP-exposure-induced liver injury in fish is associated with mitochondrial dysfunction-mediated mitophagy, ferroptosis, and cytokines. Therefore, we established grass carp hepatocyte models exposed to different concentrations of CAP (20, 40, and 80 μM) in vitro. MitoSOX probe, JC-1 staining, immunofluorescence double staining, Fe2+ staining, lipid peroxidation staining, qRT-PCR, and Western blot were used to verify the physiological regulatory mechanism of CAP induced liver injury. In the present study, the CAP-treated groups exhibited down-regulation of antioxidant-related enzyme activities and accumulation of peroxides. CAP treatment induced an increase in mitochondrial reactive oxygen species (mtROS) levels and altered expression of mitochondrial fission/fusion (Drp1, Fis1, Mfn1, Mfn2, and Opa1) genes in grass carp hepatocytes. In addition, mitophagy (Parkin, Pink1, p62, LC3II/I, and Beclin-1), ferroptosis (GPX4, COX2, ACSL4, FTH, and NCOA4), and cytokine (IFN-γ, IL-18, IL-17, IL-6, IL-10, IL-1β, IL-2, and TNF-α)-related gene expression was significantly altered. Collectively, these findings suggest that CAP exposure drives mitophagy activation, ferroptosis occurrence, and cytokine homeostasis imbalance in grass carp hepatocytes by triggering mitochondrial dysfunction mediated by the mtROS-mitochondrial fission/fusion axis. This study partly explained the physiological regulation mechanism of grass carp hepatocyte injury induced by insecticide CAP from the physiological and biochemical point of view and provided a basis for evaluating the safety of CAP environmental residues to non-target organisms.

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.

Targeting ferroptosis with natural products in liver injury: new insights from molecular mechanisms to targeted therapies

BACKGROUND

Ferroptosis is a brand-new type of controlled cell death that is distinguished by its reliance on iron and the production of lipid peroxidation. The role of ferroptosis in damaging liver disorders has attracted a lot of attention in recent years. One effective strategy to reduce liver damage is to target ferroptosis.

PURPOSE

The purpose of this review is to clarify the connection between ferroptosis and liver damage and to look into the potential contribution of natural products to the clinical management of liver damage and the discovery of novel medications.

METHODS

To study the methods by which natural products operate on ferroptosis to cure liver damage and their main signaling pathways, we searched databases from the time of initial publication to August 2023 in PubMed, EMBASE, Web of Science, Ovid, ScienceDirect, and China National Knowledge Infrastructure. The liver illness that each natural product treats is categorized and summarized. It's interesting to note that several natural compounds, such Artemether, Fucoidan sulfate, Curcumin, etc., have the benefit of having many targets and multiple pathways of action.

RESULTS

We saw that in human samples or animal models of liver injury, ferroptosis indicators were activated, lipid peroxidation levels were elevated, and iron inhibitors had the ability to reduce liver damage. Liver damage can be treated with natural products by regulating ferroptosis. This is mostly accomplished through the modulation of Nrf2-related pathways (e.g., Conclusions and Astaxanthin), biological enzymes like GPX4 and the SIRT family (e.g., Chrysophanol and Decursin), and transcription factors like P53 (e.g., Artemether and Zeaxanthin).

CONCLUSIONS

This review proposes a promising path for the therapeutic therapy of liver damage by providing a theoretical foundation for the management of ferroptosis utilizing natural ingredients.

Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases

Ferroptosis, a unique modality of cell death with mechanistic and morphological differences from other cell death modes, plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance. Aberrant epigenetic modifications and posttranslational modifications (PTMs) promote anticancer drug resistance, cancer progression, and metastasis. Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases (NSDs), cardiovascular diseases (CVDs), liver diseases, lung diseases, and kidney diseases. In this review, we first summarize the core molecular mechanisms of ferroptosis. Then, the roles of epigenetic processes, including histone PTMs, DNA methylation, and noncoding RNA regulation and PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, methylation, and ADP-ribosylation, are concisely discussed. The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases, including cancers, NSD, CVDs, liver diseases, lung diseases, and kidney diseases, as well as the application of epigenetic and PTM modulators in the therapy of these diseases, are then discussed in detail. Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases. In addition, these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases.