Aberrant iron distribution via hepatocyte-stellate cell axis drives liver lipogenesis and fibrosis

Prophylactic effects of nutrition, dietary strategies, exercise, lifestyle and environment on nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease and its prevalence has risen sharply. However, whether nutrition, dietary strategies, exercise, lifestyle and environment have preventive value for NAFLD remains unclear.

METHODS

Through searching 4 databases (PubMed, Web of Science, Embase and the Cochrane Library) from inception to January 2025, we selected studies about nutrition, dietary strategies, exercise, lifestyle and environment in the prevention of NAFLD and conducted a narrative review on this topic.

RESULTS

Reasonable nutrient intake encompassing macronutrients and micronutrients have an independent protective relationship with NAFLD. Besides, proper dietary strategies including mediterranean diet, intermittent fasting diet, ketogenic diet, and dietary approaches to stop hypertension diet have their inhibitory effects on the developmental process of NAFLD. Moreover, right exercises including walking, jogging, bicycling, and swimming are recommended for the prevention of NAFLD because they could effectively reduce weight, which is an important risk factor for NAFLD, and improve liver function. In addition, embracing a healthy lifestyle including reducing sedentary behavior, not smoking, sleeping well and brushing teeth regularly is integral since it not only could reduce the risk of NAFLD but also significantly contribute to overall prevention and control. Finally, the environment, including the social and natural environments, plays a potential role in NAFLD prevention.

CONCLUSION

Nutrition, dietary strategies, exercise, lifestyle and environment play an important role in the prevention of NAFLD. Moreover, this review offers comprehensive prevention recommendations for people at high risk of NAFLD.

Exomeres and supermeres: Current advances and perspectives

Recent studies have revealed a great diversity and complexity in extracellular vesicles and particles (EVPs). The developments in techniques and the growing awareness of the particle heterogeneity have spurred active research on new particle subsets. Latest discoveries highlighted unique features and roles of non-vesicular extracellular nanoparticles (NVEPs) as promising biomarkers and targets for diseases. These nanoparticles are distinct from extracellular vesicles (EVs) in terms of their smaller particle sizes and lack of a bilayer membrane structure and they are enriched with diverse bioactive molecules particularly proteins and RNAs, which are widely reported to be delivered and packaged in exosomes. This review is focused on the two recently identified membraneless NVEPs, exomeres and supermeres, to provide an overview of their biogenesis and contents, particularly those bioactive substances linked to their bio-properties. This review also explains the concepts and characteristics of these nanoparticles, to compare them with other EVPs, especially EVs, as well as to discuss their isolation and identification methods, research interests, potential clinical applications and open questions.

The roles and functions of ergothioneine in metabolic diseases

The global prevalence of metabolic diseases is on the increase, and it has become a significant threat to the health and lives of individuals. Ergothioneine (EGT) is a natural betaine amino acid found in various foods, particularly mushrooms. EGT cannot be synthesized by mammals; it is absorbed into small intestinal epithelial cells by a cationic protein, the novel organic cation transporter 1 (OCTN1), and transported to certain organs including liver, spleen, kidney, lung, heart, eyes and brain. EGT has been reported to exhibit antioxidant, anti-inflammatory, anti-apoptotic, anti-aging, and metal-chelating effects. The unique chemical properties and biological functions of EGT position it as a promising candidate for the research and treatment of metabolic diseases. This review summarizes EGT's capacities, potential therapeutic effects on multiple metabolic diseases, and their specific mechanisms. Finally, we outline challenges for future research on EGT and aspire to establish it as a prospective therapeutic agent for metabolic diseases.

New insights into therapeutic strategies for targeting hepatic macrophages to alleviate liver fibrosis

Liver fibrosis is a wound-healing response induced by persistent liver damage, resulting from complex multicellular interactions and multifactorial networks. Without intervention, it can progress to cirrhosis and even liver cancer. Current understanding suggests that liver fibrosis is reversible, making it crucial to explore effective therapeutic strategies for its alleviation. Chronic inflammation serves as the primary driver of liver fibrosis, with hepatic macrophages playing a dual role depending on their polarization state. This review summarizes various prevention and therapeutic strategies targeting hepatic macrophages in the context of liver fibrosis. These strategies include inhibition of macrophage recruitment, modulation of macrophage activation and polarization, regulation of macrophage metabolism, and induction of phagocytosis and autophagy in hepatic macrophages. Additionally, we discuss the communication between hepatic macrophages, hepatocytes, and hepatic stellate cells (HSCs), as well as the current clinical application of anti-fibrotic drugs targeting macrophages. The goal is to identify effective therapeutic targets at each stage of macrophage participation in liver fibrosis development, with the aim of using hepatic macrophages as a target for liver fibrosis treatment.

Ferroptosis: A novel therapeutic target for diabetic cardiomyopathy

Ferroptosis is a new type of programmed cell death caused by the accumulation of iron-dependent lipid peroxides, and it plays a role in the occurrence and progression of diverse diseases. Diabetic cardiomyopathy (DCM), a serious cardiovascular complication in patients with diabetes, eventually progresses to refractory heart failure (HF), which increases the risk of hospitalization for HF and cardiovascular death in patients with diabetes. Despite glycemic control, effective strategies to prevent DCM onset are currently lacking. Accumulating evidence suggests that ferroptosis is involved in oxidative stress, inflammation, and abnormal autophagy in diabetic myocardium, which plays an important role in myocardial apoptosis, hypertrophy, and cardiac fibrosis. The inhibition of ferroptosis can relieve DCM. Presently, ferroptosis inhibitors have been broadly suggested for the treatment of iron overload-related cardiomyopathy. This article reviewed relevant studies to offer a new therapeutic target for DCM.

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.

Taohong Siwu Decoction Modulates Glutathione Metabolism to Suppress Hepatocyte Ferroptosis and Demonstrates Anti-Fibrotic Effects in the Liver

ETHNOPHARMACOLOGICAL RELEVANCE

The ameliorative effect of traditional Chinese medicine (TCM) on hepatic fibrosis has been widely recognized and researched, but studies on the mechanism of action have been hampered by its complex composition, which requires more in-depth studies to elucidate why and how TCM works. The theory of TCM believes that the liver is closely related to blood circulation, and hepatic fibrosis is caused by blood stagnation. Taohong Siwu Decoction (THSW) is a classic formula for nourishing and invigorating blood and has been used clinically for centuries. Current evidence has demonstrated its ameliorative effect on hepatic fibrosis, but the exact mechanism of action remains unclear.

AIM OF THE STUDY

Exploring the possible mechanism of the anti-hepatic fibrosis effect of THSW by proteomics and validating with in vivo and in vitro studies.

MATERIALS AND METHODS

The carbon tetrachloride (CCl4)-induced fibrosis model was conducted in mice and treated with THSW in vivo with colchicine as the positive control. Then serum biomarker alanine aminotransferase (ALT), aspartate aminotransferase (AST), and histopathological analysis were evaluated to examine the effects of THSW. And hepatic fibrosis indicators alpha-smooth muscle actin (α-SMA) and Collagen Ⅰ (Col-Ⅰ) were detected by western blotting, immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Additionally, the 4D Label-free quantitative proteomic analysis of liver samples was applied. In vitro, erastin-induced BRL-3A cells, a rat hepatocyte line, were performed as a hepatocyte ferroptosis model and treated with or without drug-containing serum of THSW. Finally, molecular docking was used to verify the binding ability of the main components of THSW to potential targets.

RESULTS

THSW treatment significantly ameliorated serum ALT, AST, hydroxyproline (Hyp) content, α-SMA and Col-Ⅰ mRNA expression in fibrosis mice. Further results showed that THSW decreased the malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE) content and increased the glutathione (GSH) content of liver tissue. Notably, proteomic analyses have identified 294 differentially expressed proteins in the THSW-treated group compared to the model group, with 97 proteins up-regulated and 197 down-regulated. Functional analysis of these differential proteins highlights the significant roles of inflammation and oxidative stress. Further validation in vivo and in vitro, THSW significantly improved the protein expression of glutathione S-transferase M1 (GSTM1), down-regulate the expression of transferrin receptor (TFRC), and kelch-like ECH-associated protein 1(Keap1) proteins, and promote the metabolism of GSH. Especially it reduced serum iron levels, increased total iron binding capacity, and up-regulated recombinant solute carrier family 7, member 11 (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), and glutathione peroxidase 4 (GPX4) protein expression, suggesting the inhibition of hepatocyte ferroptosis. In addition, the molecular docking results showed that its main components, amygdalin, hydroxysafflor yellow A, paeoniflorin, and albiflorin, possessed good binding ability with Keap1.

CONCLUSIONS

THSW represents a novel therapeutic effect on hepatic fibrosis in mice, accompanied by inhibiting hepatocyte ferroptosis. Mechanically, THSW may regulate the glutathione metabolic pathway and TFRC expression through its main ingredients, such as amygdalin, hydroxysafflor yellow A, paeoniflorin, and albiflorin, thereby inhibiting hepatocyte ferroptosis.

Proteomics-Based Exploration of the Hepatoprotective Mechanism of α-Lipoic Acid in Rats with Iron Overload-Induced Liver Injury

Excessive iron accumulation poses a significant threat to liver health, primarily through oxidative stress and autophagy dysregulation. α-Lipoic acid (ALA), a natural antioxidant with hepatoprotective properties, may alleviate iron-induced liver damage, but its underlying mechanisms are not fully understood. This study utilized male Sprague Dawley rats and BRL-3A cells to explore the protective effects of ALA against iron overload in vivo and in vitro, respectively. ALA treatment significantly reduced hepatic iron accumulation, improved liver morphology, and alleviated iron-induced ultrastructural damage in rats. ALA also improved liver function markers in plasma, including alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), total bilirubin (TBIL), and the AST/ALT ratio. Furthermore, ALA mitigated iron-induced oxidative stress by lowering hepatic reactive oxygen species (ROS) and malondialdehyde (MDA), while increasing the antioxidant enzyme activities of glutathione peroxidase (GSH-Px) and catalase (CAT). In BRL-3A cells, ALA improved cell viability, decreased intracellular ROS, and reduced iron levels. Proteomics analysis indicates that NAD(P)H: quinone oxidoreductase 1 (NQO1) may play a critical role in the protective effects of ALA against iron overload-induced hepatic damage in rats. Mechanistically, ALA upregulated NQO1 expression while downregulating autophagy-related proteins, including light chain 3B (LC3B), lysosomal-associated membrane protein 1 (LAMP1), and cathepsin D (CTSD). Inhibition or knockdown of NQO1 abolished ALA's protective effects, confirming its role in reducing oxidative stress and excessive autophagy. These findings highlight the potential of ALA as a therapeutic agent for managing hepatic iron toxicity through iron chelation and activation of NQO1.

Advances in fluorescent probes of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the predominant chronic liver disease worldwide, with 20-30 % of individuals going on to develop non-alcoholic steatohepatitis (NASH), which could result in serious complications such as fibrosis, liver cirrhosis, and hepatocellular carcinoma. Since NAFLD is reversible in its early stages, early diagnosis is necessary. By using particular structural and functional designs, fluorescent probes can be made to detect NAFLD-related chemicals or biological processes with a high degree of sensitivity and selectivity. In this work, we summarize the existing fluorescent probes for identifying biomarkers in NAFLD, including microenvironment (viscosity, polarity), ROS, RNS, RSS, metal ions, enzymes, and RNA. Furthermore, future directions are envisioned to inform the creation of more accurate and reliable fluorescent probes for NAFLD diagnosis, emphasizing the benefits and challenges of fluorescence probes.

Extracellular Vesicle-Mediated Network in the Pathogenesis of Obesity, Diabetes, Steatotic Liver Disease, and Cardiovascular Disease

Extracellular vesicles (EVs) are lipid bilayer-enclosed particles carrying bioactive cargo, including nucleic acids, proteins, and lipids, facilitating intercellular and interorgan communication. In addition to traditional mediators such as hormones, metabolites, and cytokines, increasing evidence suggests that EVs are key modulators in various physiological and pathological processes, particularly influencing metabolic homeostasis and contributing to the progression of cardiometabolic diseases. This review provides an overview of the most recent insights into EV-mediated mechanisms involved in the pathogenesis of obesity, insulin resistance, diabetes mellitus, steatotic liver disease, atherosclerosis, and cardiovascular disease. EVs play a critical role in modulating insulin sensitivity, glucose homeostasis, systemic inflammation, and vascular health by transferring functional molecules to target cells. Understanding the EV-mediated network offers potential for identifying novel biomarkers and therapeutic targets, providing opportunities for EV-based interventions in cardiometabolic disease management. Although many challenges remain, this evolving field highlights the need for further research into EV biology and its translational applications in cardiovascular and metabolic health.

Characterization of Extracellular Vesicles Derived From Human Precision-Cut Liver Slices in Metabolic Dysfunction-Associated Steatotic Liver Disease

Extracellular vesicles (EVs) are cell-produced, membrane-surrounded vesicles that harbour the biological features of donor cells. In the current study, we are the first to isolate and characterize EVs isolated from human precision-cut liver slices (PCLS), obtained from both healthy and metabolic dysfunction-associated steatohepatitis (MASH) cirrhotic livers. PCLS derived from patients can faithfully represent disease conditions in humans. EVs were isolated from human PCLS after incubating in normal medium or modified medium that mimics the pathophysiological environment of metabolic dysfunction associated liver disease (MASLD). MASH PCLS produced higher amounts of EVs compared to healthy PCLS (p < 0.001). Mass spectrometry revealed that around 300 proteins were significantly different in EVs derived from MASH PCLS versus healthy PCLS (FDR < 0.05), irrespective of the type of medium. Significantly changed EV proteins were largely involved in signalling receptor binding function and showed potential in promoting fibrosis. In the liver, these ligand-associated receptors are highly expressed in hepatic stellate cells, and the MASH EVs functionally promoted the activation of hepatic stellate cells. Furthermore, the amounts of EpCAM and ITGA3 in EVs were positively associated with the progression of MASLD, which suggests the use of liver-derived EVs as potential biomarkers for MASLD. Characterization of EVs derived from human PCLS may assist future studies in investigating the pathogenesis and identifying liver-specific EVs as biomarkers of MASLD.

The Roles of DMT1 in Inflammatory and Degenerative Diseases

Iron homeostasis is critical for multiple physiological and pathological processes. DMT1, a core iron transporter, is expressed in almost all cells and organs and altered in response to various conditions, whereas, there is few reviews focusing on DMT1 in diseases associated with aberrant iron metabolism. Based on available knowledge, this review described a full view of DMT1 and summarized the roles of DMT1 and DMT1-mediated iron metabolism in the onset and development of inflammatory and degenerative diseases. This review also provided an overview of DMT1-related treatment in these disorders, highlighting its therapeutic potential in chronic inflammatory and degenerative diseases.

A novel EndMT inhibitor, xanthotoxin, attenuates non-alcoholic fatty liver disease by acting as TGFβR2 antagonist

BACKGROUND

Endothelial-to-mesenchymal transition (EndMT) has emerged as a key process contributing to the pathology of non-alcoholic fatty liver disease (NAFLD). Thus, identifying EndMT inhibitors may help impede NAFLD progression.

PURPOSE

Our research aims to identify potent natural EndMT inhibitors and explore their therapeutic potential and mechanisms of action in NAFLD.

METHODS

A natural compound library was employed to screen potential EndMT inhibitors. High-fat diet (HFD)-induced ApoE-/- mice and free fatty acid (FFA)-treated human hepatic sinusoidal endothelial cells (HHSECs) were employed as animal and cellular models of NAFLD. EndMT was evaluated by western blotting, qRT-PCR, immunofluorescence staining, tube formation, wound healing, and transwell assays. LC-MS/MS was applied to screen for altered secreted proteins during EndMT. Molecular docking, CETSA, and SPR assays were employed to validate the combination of xanthotoxin with TGFβR2.

RESULTS

Xanthotoxin was identified as a novel EndMT inhibitor. Further investigation revealed that xanthotoxin ameliorates NAFLD in ApoE-/- mice. By inhibiting EndMT, xanthotoxin improves endothelial dysfunction, reduces the pro-NAFLD factor ANGPTL2 secretion, and increases the anti-NAFLD factor SOD2 secretion, thus reducing hepatocyte steatosis, inflammation, and hepatic stellate cell fibrosis. Additional studies demonstrated that xanthotoxin binds to TGFβR2 and acts as its antagonist to block EndMT. In mice, EC-specific overexpression of TGFβR2 negated xanthotoxin's therapeutic impact on NAFLD.

CONCLUSION

This study reveals for the first time that xanthotoxin attenuates NAFLD by acting as a TGFβR2 antagonist to inhibit EndMT. These findings highlight the significant therapeutic potential of xanthotoxin in NAFLD treatment.

Hypoxia-inducible factor 2α mediates nonesterified fatty acids and hypoxia-induced lipid accumulation in bovine hepatocytes

Ketosis is a metabolic disorder frequently occurring in the perinatal period, characterized by elevated circulating concentrations of nonesterified fatty acids (NEFA) due to negative energy balance, resulting in fatty liver in dairy cows. However, the mechanism of hepatic steatosis induced by high concentrations of NEFA in ketosis remains unclear. Hypoxia-inducible factor 2α (HIF-2α), which mediates adaptation to hypoxic stress, plays a critical role in regulating lipid metabolism. In this study, we investigate whether HIF-2α is involved in NEFA-driven hepatic lipid accumulation in dairy cows with ketosis. Liver and blood samples were collected from 10 healthy cows (blood BHB concentration <1.2 mM) and 10 ketotic cows (blood BHB concentration >3.0 mM with clinical symptoms) with similar lactation numbers (median = 3, range = 2-4) at 3 to 9 DIM (median = 6). In cows with ketosis, serum concentrations of NEFA and BHB were greater, but serum concentrations of glucose were lower. Moreover, hepatic triglyceride content increased significantly. In the liver of ketotic cows, which was accompanied by upregulated HIF-2α expression. To determine the potential association among hypoxia, HIF-2α, and the formation of hepatocellular steatosis in vitro, we isolated hepatocytes from healthy calves for the following experiments. First, hepatocytes were treated with 0, 0.6, 1.2, or 2.4 mM NEFA (52.7 mM stock NEFA solution was diluted in RPMI-1640 basic medium supplemented with 2% fatty acid-free BSA to achieve the specified concentrations) for 18 h, showing that HIF-2α expression and cellular hypoxia occurred in a dose-dependent manner. Next, hepatocytes were infected with HIF-2α (encoded by EPAS1) small interfering RNA (Si-HIF-2α) for 48 h and then treated with 1.2 mM NEFA for 18 h. Results indicated that silencing HIF-2α decreased NEFA-induced lipid accumulation in bovine hepatocytes. Subsequently, hepatocytes treated with or without NEFA were placed in an AnaeroPack System, mimicking a hypoxic condition, for 0, 12, 18, or 24 h. Results showed that hypoxia could induce and further exacerbate lipid accumulation in bovine hepatocytes. Meanwhile, normal or NEFA-treated hepatocytes were cocultured with or without PT2385, a specific HIF-2α inhibitor, showing that hypoxia promoted steatosis through HIF-2α. Activating transcription factor 4 (ATF4) is an endoplasmic reticulum (ER) stress and hypoxia-inducible transcription factor. Here, bovine hepatocytes were treated with NEFA or hypoxia following transfecting ATF4 small interfering RNA, which demonstrated that ATF4 knockdown alleviated the extent of lipid accumulation in bovine hepatocytes. In addition, we found that ATF4 expression was correlated with HIF-2α levels in both liver tissue and cultured hepatocyte models. Moreover, overexpression of ATF4 weakened the beneficial effects of HIF-2α inhibition. Overall, these data suggest that NEFA-induced hepatic hypoxia significantly contributes to the progression of hepatic steatosis which in turn, intensifies hypoxia and leads to a self-perpetuating cycle of reciprocal causation, further exacerbating hepatic lipid deposition. Additionally, accumulated HIF-2α plays a critical role in this complex-origin steatosis, potentially through ATF4.

HLF and PPARα axis regulates metabolic-associated fatty liver disease through extracellular vesicles derived from the intestinal microbiota

Metabolic-associated fatty liver disease (MAFLD) has become increasingly widespread. The intestine is the primary site of lipid absorption and is important for the homeostasis of lipid metabolism. However, the mechanism underlying the participation of the intestinal tract in the development of MAFLD requires additional investigation. In this study, analysis of the single-cell transcriptome of intestinal tissue from cynomolgus monkeys found that hepatic leukemia factor (HLF) participated in the genetic regulation of intestinal lipid absorption. Results obtained from normal and intestine-specific Hlf-knockout mice confirmed that HLF alleviated intestinal barrier disorders by inhibiting peroxisome proliferator-activated receptor alpha (PPARα) expression. The HLF/PPARα axis alleviated MAFLD by mediating gut microbiota-derived extracellular vesicles (fEVs), thereby inhibiting hepatocyte ferroptosis. Lipidomics and functional experiments verified that taurochenodeoxycholic acid (TCDCA), a conjugated bile acid contained in the fEVs, had a key role in the process. In conclusion, intestinal HLF activity was mediated by fEVs and identified as a novel therapeutic target for MAFLD.

The Role of Solute Carrier Family Transporters in Hepatic Steatosis and Hepatic Fibrosis

Solute carrier (SLC) family transporters are crucial transmembrane proteins responsible for transporting various molecules, including amino acids, electrolytes, fatty acids, and nucleotides. To date, more than fifty SLC transporter subfamilies have been identified, many of which are linked to the progression of hepatic steatosis and fibrosis. These conditions are often caused by factors such as non-alcoholic fatty liver disease and non-alcoholic steatohepatitis, which are major contributors to the global liver disease burden. The activity of SLC members regulates the transport of substrates across biological membranes, playing key roles in lipid synthesis and metabolism, mitochondrial function, and ferroptosis. These processes, in turn, influence the function of hepatocytes, hepatic stellate cells, and macrophages, thereby contributing to the development of hepatic steatosis and fibrosis. Additionally, some SLC transporters are involved in drug transport, acting as critical regulators of drug-induced hepatic steatosis. Beyond substrate transport, certain SLC members also exhibit additional functions. Given the pivotal role of the SLC family in hepatic steatosis and fibrosis, this review aimed to summarize the molecular mechanisms through which SLC transporters influence these conditions.

Cordycepin ameliorates diabetic nephropathy injury by activating the SLC7A11/GPX4 pathway

BACKGROUND

Cordycepin (CRD) has been identified to alleviate diabetes-induced injuries and complications including diabetic nephropathy (DN). Here, this work focused on probing the specific effects and potential mechanisms of CRD on DN progression.

METHODS

High glucose (HG)-induced mouse podocyte cell line (MPC5) was used for in vitro functional analyses. Cell proliferation and apoptosis were determined using cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, and flow cytometry, respectively. ELISA analysis detected inflammatory factors. Cell ferroptosis was assessed by measuring the levels of Fe2+, glutathione, reactive oxygen species, and malonaldehyde.

RESULTS

CRD treatment suppressed HG-induced apoptosis, inflammation, and ferroptosis in podocytes. CRD treatment elevated SLC7A11 and GPX4 expression in HG-treated podocytes. The overexpression of SLC7A11 or GPX4 suppressed HG-evoked apoptosis, inflammation, and ferroptosis in podocytes. Moreover, the silencing of SLC7A11 or GPX4 abolished the protective effects of CRD on HG-treated podocytes. Moreover, CRD ameliorated renal structure injury and inflammation in STZ-induced diabetic mice by modulating SLC7A11 or GPX4 expression.

CONCLUSIONS

Cordycepin suppressed HG-induced apoptosis, inflammation, and ferroptosis in podocytes in vitro, and ameliorated renal injury and inflammation in STZ-induced diabetic mice by activating the SLC7A11/GPX4 pathway.

Regulation of Hepatic Stellate Cell Phenotypes in Metabolic Dysfunction-Associated Steatohepatitis

Hepatic stellate cells (HSCs) play a crucial role in the pathogenesis of liver fibrosis in metabolic dysfunction-associated steatohepatitis (MASH), a condition characterized by excessive fat accumulation in the hepatocytes, unrelated to alcohol consumption. In a healthy liver, HSCs are quiescent, store vitamin A, and function as pericytes. However, in response to liver injury and inflammation, HSCs become activated. In MASH, HSC activation is driven by metabolic stress, lipotoxicity, and chronic inflammation. Injured hepatocytes, recruited macrophage, capillarized sinusoidal endothelial cells, and permeable intestinal epithelium may each contribute to activating HSCS. This leads to a unique inflammatory environment that promotes fibrosis. MASH HSCs change their metabolism to favor glycolysis, glutaminolysis, and lactate generation. Activated HSCs transform into myofibroblast-like cells, producing excessive extracellular matrix components that result in fibrosis. In addition, HSCs in MASH have inflammatory and intermediate activated phenotypes. This fibrotic process is a key feature of MASH, which can lead to cirrhosis and liver cancer. Understanding the mechanisms of HSC activation and their role in MASH progression is essential for developing targeted therapies to treat and prevent liver fibrosis in affected individuals.

ATF4 drives regulatory T cell functional specification in homeostasis and obesity

Regulatory T cells (Tregs) have diverse functional specification in homeostasis and disease. However, how liver Tregs function and are transcriptionally regulated in obesity is not well understood. Here, we identified that effector Tregs expressing activating transcription factor 4 (ATF4) were enriched in the livers of obese mice. ATF4 was critical for driving an effector Treg transcriptional program, and ATF4-expressing Tregs promoted the development of obesity-induced liver fibrosis by enhancing transforming growth factor-β activation via integrin αvβ8. Treg-specific deletion of Atf4 resulted in reduced liver Tregs and attenuation of obesity-induced liver abnormalities. Furthermore, ATF4 was required to promote the differentiation of nonlymphoid tissue Treg precursors under steady state. These findings demonstrate that ATF4 is important for regulating Treg functional specification in homeostasis and obesity.

HFE-Related Hemochromatosis May Be a Primary Kupffer Cell Disease

Iron overload can lead to increased deposition of iron and cause organ damage in the liver, the pancreas, the heart and the synovium. Iron overload disorders are due to either genetic or acquired abnormalities such as excess transfusions or chronic liver diseases. The most common genetic disease of iron deposition is classic hemochromatosis (HH) type 1, which is caused by mutations of HFE. Other rare forms of HH include type 2A with mutations at the gene hemojuvelin or type 2B with mutations in HAMP that encodes hepcidin. HH type 3, is caused by mutations of the gene that encodes transferrin receptor 2. Mutations of SLC40A1 which encodes ferroportin cause either HH type 4A or HH type 4B. In the present review, an overview of iron metabolism including absorption by enterocytes and regulation of iron by macrophages, liver sinusoidal endothelial cells (LSECs) and hepatocyte production of hepcidin is presented. Hereditary Hemochromatosis and the current pathogenetic model are analyzed. Finally, a new hypothesis based on published data was suggested. The Kupffer cell is the primary defect in HFE hemochromatosis (and possibly in types 2 and 3), while the hepcidin-relative deficiency, which is the common underlying abnormality in the three types of HH, is a secondary consequence.

Serum ferritin levels and risk of gestational diabetes mellitus: A cohort study

Gestational diabetes mellitus (GDM) is a glucose metabolism disorder with an unclear etiology that occurs specifically during pregnancy. While elevated serum ferritin levels have been reported to increase the risk of GDM, these findings lack validation in large-scale studies and have yet to inform clinical practice effectively. This study enrolled 12,434 controls and 3599 GDM patients and employed binary multifactorial logistic regression, restricted cubic spline, propensity score matching, and a random forest algorithm to explore the relationship between serum ferritin and GDM, as well as the effect size of ferritin on GDM. The results indicated that GDM patients have higher serum ferritin levels compared to controls in the second and third trimesters. A weak correlation was found between serum ferritin levels and OGTT 1-hour and 2-hour blood glucose levels in the second trimester. Logistic regression (LR) and restricted cubic spline (RCS) analyses showed a significant positive correlation between serum ferritin levels and GDM in the second and third trimesters. Propensity score matching analysis indicated that the association between second-trimester serum ferritin levels and GDM remained nearly constant before and after matching. The random forest algorithm suggested that among all confounders, serum ferritin had a minimal effect on GDM risk. In conclusion, our study provides further compelling evidence for the association between serum ferritin levels and gestational diabetes mellitus. However, additional research is still needed to clarify the specific mechanisms underlying this association.

A Dynamic Deferoxamine Polymer with Exceptional Performance in Mitochondrial Iron Depletion and Cytosolic Protein Delivery

Deferoxamine (DFO) is an FDA-approved naturally occurring iron chelator commonly used to treat transfusion-induced iron overload. The abundant and flexible hydroxamic acid groups in DFO enable exceptional iron binding capacity and high protein binding via hydrogen bonding interactions. However, the applications of DFO to sequester intracellular iron and to deliver proteins inside cells are limited due to poor membrane-permeability. Herein, the fabrication of a dynamic DFO polymer is proposed to achieve robust intracellular protein delivery and efficient mitochondrial iron depletion. Specifically, DFO is grafted onto a polycatechol scaffold via dynamic catechol-boronate chemistry. The obtained DFO polymer shows robust protein binding capacity, and the formed protein complexes show high resistance toward serum proteins. It effectively delivers various cargo proteins into cytosol of treated cells with maintained bioactivity. In addition, the polymer delivers DFO inside cells, and the released DFO efficiently depletes mitochondrial iron, which significantly inhibits mitochondrial oxidative phosphorylation and glycolysis. Remarkable synergistic cytotoxic effects are achieved when the DFO polymer is loaded with toxic proteins. This study provides a general strategy for facile preparation of bioactive polymer toward robust protein delivery, and the designed polymer can be a promising carrier for the delivery of protein therapeutics to treat cancer.

The role of extracellular vesicles in non-alcoholic steatohepatitis: Emerging mechanisms, potential therapeutics and biomarkers

Non-alcoholic steatohepatitis (NASH), an emerging global healthcare problem, has become the leading cause of liver transplantation in recent decades. No effective therapies in the clinic have been proven due to the incomplete understanding of the pathogenesis of NASH, and further studies are expected to continue to delve into the mechanisms of NASH. Extracellular vesicles (EVs), which are small lipid membrane vesicles carrying proteins, microRNAs and other molecules, have been identified to play a vital role in cell-to-cell communication and are involved in the development and progression of various diseases. In recent years, there has been increasing interest in the role of EVs in NASH. Many studies have revealed that EVs mediate important pathological processes in NASH, and the role of EVs in NASH is distinct and variable depending on their origin cells and target cells. This review outlines the emerging mechanisms of EVs in the development of NASH and the preclinical evidence related to stem cell-derived EVs as a potential therapeutic strategy for NASH. Moreover, possible strategies involving EVs as clinical diagnostic, staging and prognostic biomarkers for NASH are summarized.

A novel KEAP1 inhibitor, tiliroside, activates NRF2 to protect against acetaminophen-induced oxidative stress and acute liver injury

BACKGROUND

Acetaminophen-induced acute liver injury (AILI) is one of the common causes of abrupt liver failure in numerous nations. Several previous studies revealed that tiliroside, a glycoside flavonoid, exerts neuroprotective and renal protective effects. However, whether it has hepatoprotective effects is not known. The objective of this research is to examine whether tiliroside can protect against AILI.

METHODS

AILI mouse and cell models were performed to evaluate the protective effects of tiliroside. Molecular docking, cellular thermal shift assay, immunoprecipitation, and RNA-seq were performed to analyze the possible mechanisms of tiliroside.

RESULTS

In vivo, tiliroside attenuated AILI in mice significantly, as evidenced by lower ALT and AST levels. Molecular docking, cellular thermal shift assay, and RNA-seq analysis revealed that tiliroside promoted the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and the expression of its downstream genes through disruption of the NRF2-KEAP1 protein-protein interaction to inhibit KEAP1-mediated ubiquitination and degradation of NRF2, thereby inhibiting oxidative stress in the livers of AILI mice. Furthermore, hepatocyte-specific knockout of NRF2 greatly attenuated the hepatic-protective effects of tiliroside in mice. In vitro, tiliroside protected against acetaminophen-induced oxidative stress on cultured hepatocytes through activation of NRF2. In addition, NRF2 knockout markedly blunted the protection effects of tiliroside, suggesting that NRF2 mediates the hepatic-protective effects of tiliroside.

CONCLUSIONS

Our study demonstrated that tiliroside could protect against AILI by activating the KEAP1/NRF2 pathway, which primarily inhibits the processing of oxidative stress and cell death. Our results suggest that tiliroside could serve as a potential agent for the clinical treatment of AILI.

Ferroptosis: A New Strategy for the Treatment of Fibrotic Diseases

Ferroptosis is a new type of cell death characterized by iron dependence and the excessive accumulation of lipid reactive oxygen species (lipid ROS) that has gradually become better characterized. There is sufficient evidence indicating that ferroptosis is associated with a variety of human life activities and diseases, such as tumor suppression, ischemic organ injury, and degenerative disorders. Notably, ferroptosis is also involved in the initiation and development of fibrosis in various organs, including liver fibrosis, pulmonary fibrosis, renal fibrosis, and cardiac fibrosis, which is usually irreversible and refractory. Although a large number of patients with fibrosis urgently need to be treated, the current treatment options are still limited and unsatisfactory. Organ fibrosis involves a series of complex and orderly processes, such as parenchymal cell damage, recruitment of inflammatory cells and activation of fibroblasts, which ultimately leads to the accumulation of extracellular matrix (ECM) and the formation of fibrosis. An increasing number of studies have confirmed the close association between these pathological processes and ferroptosis. This review summarizes the role and function of ferroptosis in fibrosis and proposes several potential therapeutic strategies and pathways based on ferroptosis.

Iron overload is closely associated with metabolic dysfunction-associated fatty liver disease in type 2 diabetes

OBJECTIVE

The relationship between iron metabolism disturbances and metabolic dysfunction-associated fatty liver disease (MAFLD) remains controversial. This study aimed to investigate the association of iron overload with MAFLD in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study included 155 Chinese inpatients with T2DM. MAFLD was diagnosed and grouped using magnetic resonance imaging (MRI). MRI biomarkers such as proton density fat fraction and iron accumulation (R 2 * ) were measured. Their clinical characteristics were compared, and the association of iron metabolism markers with MAFLD in patients with T2DM was analyzed.

RESULTS

Iron metabolism markers, including MRI-R 2 * , ferritin, serum iron, hepcidin, and total iron-binding capacity, were overloaded in groups with MAFLD (p < 0.001 for trend). They were positively correlated with MAFLD and reflected the severity of MAFLD. The five markers of logistic regression analysis revealed an increased MAFLD risk (p < 0.001 for trend). The areas under the curve of five markers all exceeded 0.5, indicating certain predictive values for MAFLD.

CONCLUSIONS

MAFLD is associated with significant iron overload in Chinese patients with T2DM. Serum iron, ferritin, total iron-binding capacity, hepcidin, andR 2 * value are essential iron metabolism markers to evaluate and predict the progression of MAFLD in patients with T2DM.

Exploring the Role of Metabolic Hyperferritinaemia (MHF) in Steatotic Liver Disease (SLD) and Hepatocellular Carcinoma (HCC)

The increasing prevalence of the spectrum of Steatotic Liver Disease (SLD), including Metabolic-Associated Steatotic Liver Disease (MASLD), Metabolic-Associated Steatohepatitis (MASH), and progression to Cirrhosis and Hepatocellular Carcinoma (HCC) has led to intense research in disease pathophysiology, with many studies focusing on the role of iron. Iron overload, which is often observed in patients with SLD as a part of metabolic hyperferritinaemia (MHF), particularly in the reticuloendothelial system (RES), can exacerbate steatosis. This imbalance in iron distribution, coupled with a high-fat diet, can further promote the progression of SLD by means of oxidative stress triggering inflammation and activating hepatic stellate cells (HSCs), therefore leading to fibrosis and progression of simple steatosis to the more severe MASH. The influence of iron overload in disease progression has also been shown by the complex role of ferroptosis, a type of cell death driven by iron-dependent lipid peroxidation. Ferroptosis depletes the liver's antioxidant capacity, further contributing to the development of MASH, while its role in MASH-related HCC is potentially linked to alternations in the tumour microenvironment, as well as ferroptosis resistance. The iron-rich steatotic hepatic environment becomes prone to hepatocarcinogenesis by activation of several pro-carcinogenic mechanisms including epithelial-to-mesenchymal transition and deactivation of DNA damage repair. Biochemical markers of iron overload and deranged metabolism have been linked to all stages of SLD and its associated HCC in multiple patient cohorts of diverse genetic backgrounds, enhancing our daily clinical understanding of this interaction. Further understanding could lead to enhanced therapies for SLD management and prevention.

Transferrin promotes fatty acid oxidation and liver tumor growth through PHD2-mediated PPARα hydroxylation in an iron-dependent manner

Tumor cells reshape iron and lipid metabolism for their rapid proliferation. However, how tumor cells coordinate the interplay between tumor cell-specific iron homeostasis and lipid metabolism reprogramming to counteract energy shortages remains unclear. Here, we demonstrated that glucose deprivation in hepatocellular carcinoma (HCC) cells induced AMPK-dependent Transferrin S685 phosphorylation, which exposed Transferrin nuclear localization signal (NLS) for binding to importin α7 and subsequent nuclear translocation. Nucleus-translocated Transferrin interacts with PPARα and enhance its protein stability to increase fatty acid oxidation (FAO) upon glucose deprivation. Mechanistically, PPARα-associated Transferrin upregulates iron-dependent PHD2-mediated PPARα P87 hydroxylation and subsequently disrupts the binding of MDM2 to PPARα, therefore inhibiting MDM2-mediated PPARα ubiquitination and degradation. Reconstitution of Transferrin S685A and NLS mutation or knock-in expression of PPARα P87A inhibited PPARα-mediated FAO upon energy stress, enhanced HCC cell apoptosis, and impeded liver tumor growth in mice. Importantly, combined treatment with Transferrin pS685 blocking peptide suppressing AMPK-Transferrin-PPARα axis could synergize with a well-established AMPK activator Metformin to inhibit tumor growth. Additionally, Transferrin pS685-mediated PPARα P87 hydroxylation is positively correlated with PPARα expression levels in human HCC specimens and poor patient prognosis. These findings revealed a mechanism by which Transferrin can sense energy stress to promote the hydroxylation and protein stability of PPARα through iron-dependent activation of PHD2 and underscore the moonlighting function of Transferrin in lipid catabolism and liver tumor development.

Fraxinellone-mediated targeting of cathepsin B leakage from lysosomes induces ferroptosis in fibroblasts to inhibit hypertrophic scar formation

BACKGROUND

Hypertrophic scar (HS) is a common fibrotic skin disorder characterized by the excessive deposition of extracellular matrix (ECM). Fibroblasts are the most important effector cells involved in HS formation. Currently no satisfactory treatment has been developed.

METHODS

The impact of fraxinellone (FRA) on the proliferation and migration capacity of human hypertrophic scar-derived fibroblasts (HSFs) was assessed by EdU proliferation, wound healing and transwell assays. Quantitative real-time PCR (qRT‒PCR), Western blot (WB), immunofluorescence staining and collagen gel contraction assays were performed to evaluate the collagen production and activation capacity of HSFs. Oxford Nanopore Technologies long-read RNA sequencing (ONT long-read RNA-seq) revealed the occurrence of ferroptosis in HSF and ferroptosis executioner-cathepsin B (CTSB). The mechanisms underlying FRA-induced HSF ferroptosis were examined through fluorescence staining, qRT‒PCR, WB and molecular docking study. The therapeutic efficacy of FRA was further validated in vivo using a rabbit ear scar model.

RESULTS

FRA treatment significantly suppressed the proliferation, migration, collagen production and activation capacity of HSFs. ONT long-read RNA-seq discovered that FRA modulated the expression of transcripts related to ferroptosis and lysosomes. Mechanistically, FRA treatment reduced the protein expression level of glutathione peroxidase 4 (GPX4) and induced the release of CTSB from lysosomes into the cytoplasm. CTSB further induced ferroptosis via spermidine/spermine-N1-acetyltransferase (SAT1)-mediated lipid peroxidation, mitochondrial damage and mitogen-activated protein kinase (MAPK) signalling pathway activation, eventually affecting the function of HSFs. Moreover, FRA treatment attenuated the formation of HS in rabbit ears via CTSB-mediated ferroptosis. The antifibrotic effects of FRA were abrogated by pretreatment with a CTSB inhibitor (CA-074-me).

CONCLUSIONS

This study reveals that FRA ameliorates HS by inducing CTSB leakage from lysosomes, causing SAT1-mediated lipid peroxidation, mitochondrial damage and MAPK signalling pathway activation, thus mediating HSF ferroptosis. Therefore, FRA could be a promising therapeutic agent for treating HS.

Serum Ferritin Levels and Liver-Related Events in Individuals With Steatotic Liver Disease: A Longitudinal Cohort Study

BACKGROUND

Serum ferritin has been suggested as a potential biomarker associated with disease progression in metabolic dysfunction-associated steatotic liver disease (MASLD).

AIMS

We investigated the association between serum ferritin levels and liver-related events (LREs) in individuals with steatotic liver disease (SLD).

METHODS

This cohort study included 17,560 adults with SLD (MASLD [n = 15,744], MASLD with increased alcohol intake (MetALD) [n = 1103] and cryptogenic SLD [n = 713]) without LRE at baseline. A steatotic liver was diagnosed using ultrasound, and LRE was defined as the development of decompensation (ascites, variceal bleeding and hepatic encephalopathy) or hepatocellular carcinoma. Participants were categorised into high (≥ 300 μg/L for males, ≥ 200 μg/L for females) or normal to low (< 300 μg/L for males, < 200 μg/L for females) ferritin levels.

RESULTS

During 211,425 person-years of follow-up (median: 12.3 years), 74 incident LRE cases were identified, with 63 cases in MASLD, 10 in MetALD and 1 in cryptogenic SLD. The multivariable-adjusted hazard ratio (aHR) for LRE comparing individuals with high and normal-to-low ferritin level was 3.13 (95% confidence interval [CI] 1.89-5.18). Increased risk of LRE in individuals with high serum ferritin level compared to those with normal to low serum ferritin level was consistent across SLD subtypes (aHR 2.69, 95% CI 1.55-4.67 for MASLD; aHR 5.73, 95% CI 1.31-25.0 for MetALD), and SLD severity assessed by Fibrosis-4 (FIB-4) index (aHR 2.38, 95% CI 1.34-4.21 for FIB-4 ≥ 1.3; aHR 3.13, 95% CI 1.18-8.29 for FIB-4 < 1.3).

CONCLUSIONS

Serum ferritin levels correlated with the risk of LRE in patients with SLD.

Targeting ion homeostasis in metabolic diseases: Molecular mechanisms and targeted therapies

The incidence of metabolic diseases-hypertension, diabetes, obesity, metabolic dysfunction-associated steatotic liver disease (MASLD), and atherosclerosis-is increasing annually, imposing a significant burden on both human health and the social economy. The occurrence and development of these diseases are closely related to the disruption of ion homeostasis, which is crucial for maintaining cellular functions and metabolic equilibrium. However, the specific mechanism of ion homeostasis in metabolic diseases is still unclear. This article reviews the role of ion homeostasis in the pathogenesis of metabolic diseases and assesses its potential as a therapeutic target. Furthermore, the article explores pharmacological strategies that target ion channels and transporters, including existing drugs and emerging drugs under development. Lastly, the article discusses the development direction of future therapeutic strategies, including the possibility of gene therapy targeting specific ion channels and personalized therapy using novel biomarkers. In summary, targeting ion homeostasis provides a new perspective and potential therapeutic approach for the treatment of metabolic diseases.

Metabolic Messengers: small extracellular vesicles

Small extracellular vesicles (sEVs) are signalling molecules and biomarkers of cell status that govern a complex intraorgan and interorgan communication system through their cargo. Initially recognized as a waste disposal mechanism, they have emerged as important metabolic regulators. They transfer biological signals to recipient cells through their cargo content, and microRNAs (miRNAs) often mediate their metabolic effects. This review provides a concise overview of sEVs, specifically in the context of obesity-associated chronic inflammation and related metabolic disorders, describing their role as metabolic messengers, identifying their key sites of action and elucidating their mechanisms. We highlight studies that have shaped our understanding of sEV metabolism, address critical questions for future exploration, discuss the use of miRNAs as disease biomarkers and provide insights into the therapeutic potential of sEVs or specific miRNAs for treating metabolic diseases and related disorders in the future.

Metal Ion Signaling in Biomedicine

Complex multicellular organisms are composed of distinct tissues involving specialized cells that can perform specific functions, making such life forms possible. Species are defined by their genomes, and differences between individuals within a given species directly result from variations in their genetic codes. While genetic alterations can give rise to disease-causing acquisitions of distinct cell identities, it is now well-established that biochemical imbalances within a cell can also lead to cellular dysfunction and diseases. Specifically, nongenetic chemical events orchestrate cell metabolism and transcriptional programs that govern functional cell identity. Thus, imbalances in cell signaling, which broadly defines the conversion of extracellular signals into intracellular biochemical changes, can also contribute to the acquisition of diseased cell states. Metal ions exhibit unique chemical properties that can be exploited by the cell. For instance, metal ions maintain the ionic balance within the cell, coordinate amino acid residues or nucleobases altering folding and function of biomolecules, or directly catalyze specific chemical reactions. Thus, metals are essential cell signaling effectors in normal physiology and disease. Deciphering metal ion signaling is a challenging endeavor that can illuminate pathways to be targeted for therapeutic intervention. Here, we review key cellular processes where metal ions play essential roles and describe how targeting metal ion signaling pathways has been instrumental to dissecting the biochemistry of the cell and how this has led to the development of effective therapeutic strategies.

Iron-Mediated Regulation in Adipose Tissue: A Comprehensive Review of Metabolism and Physiological Effects

PURPOSE OF REVIEW

Review the latest data regarding the intersection of adipose tissue (AT) and iron to meet the needs of AT metabolism and the progression of related diseases.

RECENT FINDINGS

Iron is involved in fundamental biological metabolic processes and is precisely fine-tuned within the body to maintain cellular, tissue and even systemic iron homeostasis. AT not only serves as an energy storage depot but also represents the largest endocrine organ in the human body, maintaining systemic metabolic homeostasis. It is involved in physiological processes such as energy storage, insulin sensitivity regulation and lipid metabolism. As a unique iron-sensing tissue, AT expresses related regulatory factors, including the classic hepcidin, ferroportin (FPN), iron regulatory protein/iron responsive element (IRP/IRE) and ferritin. Consequently, the interaction between AT and iron is intricately intertwined. Imbalance of iron homeostasis produces the potential risks of steatosis, impaired glucose tolerance and insulin resistance, leading to AT dysfunction diseases, including obesity, type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD). Despite the role of AT iron has garnered increasing attention in recent years, a comprehensive review that systematically organizes the connection between iron and AT remains lacking. Given the necessity of iron homeostasis, emphasizing its potential impact on AT function and metabolism regulation provides valuable insights into physiological effects such as adipocyte differentiation and thermogenesis. Futhermore, regulators including adipokines, mitochondria and macrophages have been mentioned, along with analyzing the novel perspective of iron as a key mediator influencing the fat-gut crosstalk.

Hepatocyte HIF-2α aggravates NAFLD by inducing ferroptosis through increasing extracellular iron

Recent research has illuminated the pivotal role of the hypoxia-inducible factor-2α (HIF-2α)/peroxisome proliferator-activated receptor alpha (PPARα) pathway in the progression of nonalcoholic fatty liver disease (NAFLD). Meanwhile, it has been reported that HIF-2α is involved in iron regulation, and that aberrant iron distribution leads to liver lipogenesis. Therefore, we hypothesize that HIF-2α exacerbates fatty liver by affecting iron distribution. To substantiate this hypothesis, we utilized liver-specific HIF-2α knockout mice and the LO2 cell line with overexpressed HIF-2α. HIF-2α overexpression (OE) was induced via lentiviral infection, followed by exposure to free fatty acids (FFAs) and deferoxamine (DFO). In animal experiments, hepatic HIF-2α knockout resulted in lower liver lipid levels, lower liver weight, and higher serum iron levels. Enrichment in autophagy, ferroptosis, and the PI3K-AKT pathway was demonstrated through Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis in the liver of mice. In vitro experiments showed that HIF-2α increased supernatant iron. In the HIF-2α OE group, the addition of FFA led to decreased levels of reduced glutathione (GSH) and glutathione peroxidase 4 (GPX4) protein, along with increased lipid peroxidation (LPO), cellular lipid droplets, and triglyceride content. Impressively, DFO intervention decreased supernatant iron, reversed these changes by increasing GSH and GPX4 levels, and simultaneously reduced LPO levels, cellular lipid droplets, and triglyceride content. In addition, the expression of proteins related to β-oxidation increased, and lipid deposition in hepatocytes improved, which may be associated with the PI3K/AKT pathway. In summary, our findings suggest that HIF-2α-mediated iron flux enhances NAFLD cell susceptibility to ferroptosis, thereby impacting lipid metabolism-related genes and contributing to lipid accumulation.NEW & NOTEWORTHY The experiment demonstrated that HIF-2α increased extracellular iron. In LO2 cells overexpressing HIF-2α, FFAs not only increased cellular lipid and triglyceride levels but also induced key features of ferroptosis, such as reduced GSH and GPX4 levels and increased LPO, despite the absence of cellular iron overload. These effects were reversed by lowering extracellular iron with DFO. Furthermore, DFO treatment increased β-oxidation protein expression and improved lipid deposition in hepatocytes, potentially through the PI3K/AKT pathway.

Dietary Iron Overload Triggers Hepatic Metabolic Disorders and Inflammation in Laying Hen

Iron, an essential trace element, is involved in various physiological processes; however, consumption of excessive iron possesses detrimental effects. In practical feed production, the iron content added to feeds often far exceeds the actual demand, resulting in an excess of iron in the body. The liver as a central regulator of iron homeostasis is susceptible to damage caused by disorders in iron metabolism. A model of hepatic iron overload in laying hens was developed in this study by incorporating iron into their diet, and the specific mechanisms underlying iron overload-induced hepatic injury were investigated. Firstly, this study revealed that a high-iron diet resulted in hepatic iron overload, accompanied by impaired liver function. Next, assessment of oxidative stress markers indicated a decrease in activities of T-SOD and CAT, coupled with an increase in MDA content, pointing to the iron-overloaded liver oxidative stress. Thirdly, the impact of iron overload on hepatic glycolipid and bile acid metabolism-related gene expressions were explored, including PPAR-α, GLUT2, and CYP7A1, highlighting disruptions in hepatic metabolism. Subsequently, analyses of inflammation-related genes such as iNOS and IL-1β at both protein and mRNA levels demonstrated the presence of inflammation in the liver under conditions of dietary iron overload. Overall, this study provided comprehensive evidence that dietary iron overload contributed to disorders in glycolipid and bile acid metabolism, accompanied by inflammatory responses in laying hens. Further detailing the specific pathways involved and the implications of these findings could offer valuable insights for future research and practical applications in poultry nutrition.

Immunological dynamics in MASH: from landscape analysis to therapeutic intervention

Metabolic dysfunction-associated steatohepatitis (MASH), previously known as nonalcoholic steatohepatitis (NASH), is a multifaceted liver disease characterized by inflammation and fibrosis that develops from simple steatosis. Immune and inflammatory pathways have a central role in the pathogenesis of MASH, yet, how to target immune pathways to treat MASH remains perplexed. This review emphasizes the intricate role that immune cells play in the etiology and pathophysiology of MASH and highlights their significance as targets for therapeutic approaches. It discusses both current strategies and novel therapies aimed at modulating the immune response in MASH. It also highlights challenges in liver-specific drug delivery, potential off-target effects, and difficulties in targeting diverse immune cell populations within the liver. This review is a comprehensive resource that integrates current knowledge with future perspectives in the evolving field of MASH, with the goal of driving forward progress in medical therapies designed to treat this complex liver disease.

Ficus hirta Vahl. ameliorates liver fibrosis by triggering hepatic stellate cell ferroptosis through GSH/GPX4 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus hirta Vahl., a traditional Chinese medicine commonly used in the Lingnan region, has been extensively used for liver disease treatment in China. Its notable antioxidant and anti-inflammatory properties have been reported in previous studies. However, its potential effect and underlying mechanism on liver fibrosis remains unclear.

AIM OF STUDY

This study was aimed to investigate the effect and its underlying mechanism of Ficus hirta Vahl on liver fibrosis in vitro and in vivo.

MATERIALS AND METHODS

The main components of Ficus hirta Vahl in blood were investigated by using UPLC-Q/TOF-MS/MS. Two animal models of liver fibrosis, the CCl4 and MCD induced mice, were used to assess the efficacy of Ficus hirta Vahl on liver fibrosis. Metabolomics was used to detect the level of metabolites in the serum of liver fibrosis mice after Ficus hirta Vahl treatment. Furthermore, the mechanism was validated in vitro using the human liver stellate cell line LX-2. The binding affinities of the active ingredients of Ficus hirta Vahl to the main targets of liver fibrosis were also determined. Finally, we identified the key active ingredients responsible for the treatment of liver fibrosis in vivo.

RESULTS

Fibrosis and inflammatory markers were significant down-regulation in both CCl4 and MCD induced liver fibrosis mice after Ficus hirta Vahl administration in a dose-dependent manner. We found that Ficus hirta Vahl may primarily exert its effect on liver fibrosis through the glutathione metabolic pathway. Importantly, the glutathione metabolic pathway is closely associated with ferroptosis, and our subsequent in vitro experiments provided evidence supporting this association. Ficus hirta Vahl was found to modulate the GSH/GPX4 pathway, ultimately leading to the amelioration of liver fibrosis. Moreover, using serum pharmacochemistry and molecular docking, we successfully identified apigenin as a probable efficacious monomer for the management of liver fibrosis and subsequently validated its efficacy in mice with CCl4-induced hepatic fibrosis.

CONCLUSION

Ficus hirta Vahl triggered the ferroptosis of hepatic stellate cell by regulating the GSH/GPX4 pathway, thereby alleviating liver fibrosis in mice. Moreover, apigenin is a key compound in Ficus hirta Vahl responsible for the effective treatment of liver fibrosis.

Kaempferol Remodels Liver Monocyte Populations and Treats Hepatic Fibrosis in Mice by Modulating Intestinal Flora and Metabolic Reprogramming

Changes in gut flora are associated with liver fibrosis. The interactions of host with intestinal flora are still unknown, with little research investigating such interactions with comprehensive multi-omics data. The present work analyzed and integrated large-scale multi-omics transcriptomics, microbiome, metabolome, and single-cell RNA-sequencing datasets from Kaempferol-treated and untreated control groups by advanced bioinformatics methods. This study concludes that kaempferol dose-dependently improved serum markers (like AST, ALT, TBil, Alb, and PT) and suppressed fibrosis markers (including HA, PC III, LN, α-SMA, and Collagen I), while kaempferol also increased body weight. Mechanistically, kaempferol improved the metabolic levels of intestinal flora dysbiosis and associated lipids. This was achieved by increasing the abundance of g__Robinsoniella, g__Erysipelotrichaceae_UCG-003, g__Coriobacteriaceae_UCG-002, and 5-Methylcytidine, all-trans-5,6- Epoxyretinoic acid, LPI (18:0), LPI (20:4), etc. to achieve this. Kaemferol exerts anti-inflammatory and immune-enhancing effects by down-regulating the Th17/IL-17 signaling pathway in PDGF-induced LX2 cells. In addition, kaempferol administration remarkably elevated CD4 + T and CD8 + T cellular proportions, thereby activating immune cells for protecting the body and controlling inflammatory conditions. The combined interaction of multiple data may explain how Kaempferol modulates the intestinal flora thereby remodeling the hepatocyte population and alleviating liver fibrosis.

Myokines and Their Potential Protective Role Against Oxidative Stress in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Myokines, bioactive peptides released by skeletal muscle, have emerged as crucial regulators of metabolic and protective pathways in peripheral tissues, particularly in combating oxidative stress and inflammation. Their plasma concentration significantly increases following exercise, offering valuable insights into the role of physical activity in preventing sarcopenia and mitigating metabolic diseases, including obesity, diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). This review focuses on discussing the roles of specific myokines in activating intracellular signaling pathways within the liver, which confer protection against steatosis and lipid peroxidation. We detail the mechanism underlying lipid peroxidation and highlight the liver's antioxidant defenses, such as glutathione (GSH) and glutathione peroxidase 4 (GPX4), which are pivotal in reducing ferroptosis. Furthermore, we provide an in-depth analysis of key myokines, including myostatin, brain-derived neurotrophic factor (BDNF), and irisin, among others, and their potential impact on liver function. Finally, we discuss the molecular mechanisms through which these myokines influence oxidate stress and lipid metabolism, emphasizing their capacity to modulate antioxidant responses in the liver. Finally, we underscore the therapeutic potential of exercise as a non-pharmacological intervention to enhance myokine release, thereby preventing the progression of MASD through improved hepatic antioxidant defenses. This review represents a comprehensive perspective on the intersection of exercise, myokine biology, and liver health.

Epidemiological and transcriptome data identify association between iron overload and metabolic dysfunction-associated steatotic liver disease and hepatic fibrosis

The primary objective of this study was to examine the association between iron overload (IO), metabolic dysfunction-associated steatotic liver disease (MASLD), and hepatic fibrosis. We hypothesized that there is a significant association. Data from the NHANES (2017-2020) were analyzed to explore IO's impact on MASLD and hepatic fibrosis in U.S. adults. We assessed serum ferritin, controlled attenuation parameter (CAP), liver stiffness measurement (LSM), and various covariates. Gene expression data were sourced from the FerrDb V2 and GEO databases. Differential gene expression analysis, Protein-Protein Interaction (PPI) Network construction, and Gene Ontology (GO) and KEGG pathway enrichment analyses were performed. The study verified the link between MASLD, hepatic fibrosis, and iron overload hub genes. This study of 5927 participants, averaging 46.78 years of age, revealed significant correlations between serum ferritin and CAP, LSM, after adjusting for covariates. Threshold effect analysis indicated nonlinear associations between serum ferritin and CAP, LSM, with distinct patterns observed by age and gender. Moreover, the area under the ROC curve for serum ferritin with MASLD and hepatic fibrosis was 0.8272 and 0.8376, respectively, demonstrating its performance in assessing these conditions. Additionally, molecular analyses identified potential hub genes associated with iron overload and MASLD, and hepatic fibrosis, revealing the underlying mechanisms. Our study findings reveal an association between iron overload, MASLD, and hepatic fibrosis. Additionally, the hub genes may be implicated in iron overload and subsequently contribute to the progression of MASLD and hepatic fibrosis. These findings support precision nutrition strategies.

Cholinized-Polymer Functionalized Lipid-Based Drug Carriers Facilitate Liver Fibrosis Therapy via Ultrafast Liver-Targeting Delivery

Here, we report novel cholinized-polymer functionalized lipid-based nanoparticles (CP-LNPs) for rapid and highly effective delivery of drugs to the liver, achieving targeting within 10 min and nearly 100% efficiency. In this study, CP-LNPs loaded with a promising antifibrotic agent curcumin (CP-LNPs/Cur) significantly improved the stability of curcumin under physiological conditions and its distribution in the liver. In vitro experiments demonstrated that CP-LNPs/Cur effectively suppressed the proliferation and migration of activated hepatic stellate cells (aHSCs), as evidenced by the decreased expression of α-SMA. Moreover, CP-LNPs/Cur attenuated oxidative stress levels in hepatocytes while improving mitochondrial physiological activity. In vivo antifibrosis studies have shown that CP-LNPs/Cur only require a low dose to significantly alleviate liver injury and collagen deposition, thereby preventing the progression of liver fibrosis. These findings indicated that CP-LNPs exhibit great potential in liver fibrosis therapy benefiting from the novel targeting strategy.

Novel insights into the role of immunomodulatory extracellular vesicles in the pathogenesis of liver fibrosis

Liver fibrosis, a chronic and long-term disease, can develop into hepatocellular carcinoma (HCC) and ultimately lead to liver failure. Early diagnosis and effective treatment still face significant challenges. Liver inflammation leads to liver fibrosis through continuous activation of hepatic stellate cells (HSCs) and the accumulation of immune cells. Intracellular communication among various immune cells is important for mediating the inflammatory response during fibrogenesis. Extracellular vesicles (EVs), which are lipid bilayer membrane-enclosed particles naturally secreted by cells, make great contributions to cell-cell communication and the transport of bioactive molecules. Nearly all the cells that participate in liver fibrosis release EVs loaded with lipids, proteins, and nucleic acids. EVs from hepatocytes, immune cells and stem cells are involved in mediating the inflammatory microenvironment of liver fibrosis. Recently, an increasing number of extracellular vesicle-based clinical applications have emerged, providing promising cell-free diagnostic and therapeutic tools for liver fibrosis because of their crucial role in immunomodulation during pathogenesis. The advantages of extracellular vesicle-based therapies include stability, biocompatibility, low cytotoxicity, and minimal immunogenicity, which highlight their great potential for drug delivery and specific treatments for liver fibrosis. In this review, we summarize the complex biological functions of EVs in the inflammatory response in the pathogenesis of liver fibrosis and evaluate the potential of EVs in the diagnosis and treatment of liver fibrosis.

Serum iron status is associated with all-cause mortality in metabolic dysfunction-associated steatotic liver disease: a prospective, observational study

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading chronic liver disease worldwide. Emerging evidence suggests a close crosstalk between iron status and metabolic syndrome. Therefore, this cohort study aimed to investigate the relationship between serum iron status and all-cause mortality in individuals with MASLD.

Methods

A total of 3393 subjects with MASLD identified by ultrasound from the Third National Health and Nutrition Examination Survey (NHANES III) were included in the analysis. Iron status indicators included serum iron, ferritin, transferrin saturation, total iron binding capacity, hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin concentration. Cox proportional hazards models and restricted cubic spline models with adjustment for multiple confounders were applied. Stratified analyses were performed by sex and age.

Results

During a median of 26.08 years of follow-up, high serum iron and transferrin saturation were significantly associated with reduced all-cause mortality in a linear pattern (P overall<0.001). Compared with the lowest quartile, individuals with serum iron and transferrin saturation in the third or fourth quartile intervals had a 20-40% reduction in long-term mortality. However, there was no independent association of serum ferritin, total iron binding capacity, and red blood cell indices with all-cause mortality in MASLD.

Conclusion

This study suggests that serum iron and transferrin saturation have the potential to serve as independent biomarkers of all-cause mortality in patients with MASLD and implies the therapeutic potential of modifying iron status.

Bile from the hemojuvelin-deficient mouse model of iron excess is enriched in iron and ferritin

Iron is an essential nutrient but is toxic in excess. Iron deficiency is the most prevalent nutritional deficiency and typically linked to inadequate intake. Iron excess is also common and usually due to genetic defects that perturb expression of hepcidin, a hormone that inhibits dietary iron absorption. Our understanding of iron absorption far exceeds that of iron excretion, which is believed to contribute minimally to iron homeostasis. Prior to the discovery of hepcidin, multiple studies showed that excess iron undergoes biliary excretion. We recently reported that wild-type mice raised on an iron-rich diet have increased bile levels of iron and ferritin, a multi-subunit iron storage protein. Given that genetic defects leading to excessive iron absorption are much more common causes of iron excess than dietary loading, we set out to determine if an inherited form of iron excess known as hereditary hemochromatosis also results in bile iron loading. We employed mice deficient in hemojuvelin, a protein essential for hepcidin expression. Mutant mice developed bile iron and ferritin excess. While lysosomal exocytosis has been implicated in ferritin export into bile, knockdown of Tfeb, a regulator of lysosomal biogenesis and function, did not impact bile iron or ferritin levels. Bile proteomes differed between female and male mice for wild-type and hemojuvelin-deficient mice, suggesting sex and iron excess impact bile protein content. Overall, our findings support the notion that excess iron undergoes biliary excretion in genetically determined iron excess.

The role of ferroptosis in DM-induced liver injury

The liver damage caused by Diabetes Mellitus (DM) has attracted increasing attention in recent years. Liver injury in DM can be caused by ferroptosis, a form of cell death caused by iron overload. However, the role of iron transporters in this context is still not clear. Herein, we attempted to shed light on the pathophysiological mechanism of ferroptosis. DM was induced in 8-week-old male rats by streptozotocin (STZ) before assessment of the degree of liver injury. Together with histopathological changes, variations in glutathione peroxidase 4 (GPX4), glutathione (GSH), superoxide dismutase (SOD), transferrin receptor 1 (TFR1), ferritin heavy chain (FTH), ferritin light chain (FTL), ferroportin and Prussian blue staining, were monitored in rat livers before and after treatment with Fer-1. In the liver of STZ-treated rats, GSH and SOD levels decreased, whereas those of malondialdehyde (MDA) increased. Expression of TFR1, FTH and FTL increased whereas that of glutathione peroxidase 4 (GPX4) and ferroportin did not change significantly. Prussian blue staining showed that iron levels increased. Histopathology showed liver fibrosis and decreased glycogen content. Fer-1 treatment reduced iron and MDA levels but GSH and SOD levels were unchanged. Expression of FTH and FTL was reduced whereas that of ferroportin showed a mild decrease. Fer-1 treatment alleviated liver fibrosis, increased glycogen content and mildly improved liver function. Our study demonstrates that ferroptosis is involved in DM-induced liver injury. Regulating the levels of iron transporters may become a new therapeutic strategy in ferroptosis-induced liver injury.

Ferroptosis at the nexus of metabolism and metabolic diseases

Ferroptosis, an iron-dependent form of regulated cell death, is emerging as a crucial regulator of human physiology and pathology. Increasing evidence showcases a reciprocal relationship between ferroptosis and dysregulated metabolism, propagating a pathogenic vicious cycle that exacerbates pathology and human diseases, particularly metabolic disorders. Consequently, there is a rapidly growing interest in developing ferroptosis-based therapeutics. Therefore, a comprehensive understanding of the intricate interplay between ferroptosis and metabolism could provide an invaluable resource for mechanistic insight and therapeutic development. In this review, we summarize the important metabolic substances and associated pathways in ferroptosis initiation and progression, outline the cascade responses of ferroptosis in disease development, overview the roles and mechanisms of ferroptosis in metabolic diseases, introduce the methods for ferroptosis detection, and discuss the therapeutic perspectives of ferroptosis, which collectively aim to illustrate a comprehensive view of ferroptosis in basic, translational, and clinical science.

Cryptotanshinone alleviates liver fibrosis via inhibiting STAT3/CPT1A-dependent fatty acid oxidation in hepatic stellate cells

Hepatic stellate cells (HSCs) are a major source of fibrogenic cells and play a central role in liver fibrogenesis. HSC activation depends on metabolic activation, for which it is well established that fatty acid oxidation (FAO) sustains their rapid proliferative rate. Studies have indicated that tanshinones inhibit HSC activation, however, the anti-fibrosis mechanisms of tanshinones are remain unclear. Herein, we reported that cryptotanshinone (CTS), a lipid-soluble ingredient of Salvia miltiorrhiza Bunge, exhibited the strongest inhibitory effects on HSC-LX2 proliferation and activation. CTS could induce lipocyte phenotype in mouse primary HSC and HSC-LX2. Transcriptomic sequencing and qPCR revealed that CTS regulated fatty acid metabolism and inhibited CPT1A and CPT1B expression. Target prediction suggested CTS regulates lipid metabolism by targeting STAT3. Mechanistically, the level of ATP and acetyl-CoA were reduced by the treatment of CTS, indicating that CTS could inhibit the level of FAO. Furthermore, CTS could inhibit the phosphorylation and nuclear translocation of STAT3. Additionally, CPT1A overexpression reversed the efficacy of CTS. Finally, CTS (40 mg/kg/day) attenuated CCl4-induced liver fibrosis and inhibited collagen production and HSC activation. Moreover, the results of immunofluorescence showed that α-SMA and p-STAT3 were co-located, and CTS could reduce the levels of p-STAT3 and α-SMA. In summary, CTS alleviated liver fibrosis by inhibiting the p-STAT3/CPT1A-dependent FAO both in vitro and in vivo, making it a potential candidate drug for the treatment of liver fibrosis.

Iron-dependent KDM4D activity controls the quiescence-activity balance of MSCs via the PI3K-Akt-Foxo1 pathway

Iron deficiency is a prevalent nutritional deficit associated with organ damage and dysfunction. Recent research increasingly associates iron deficiency with bone metabolism dysfunction, although the precise underlying mechanisms remain unclear. Some studies have proposed that iron-dependent methylation-erasing enzyme activity regulates cell proliferation and differentiation under physiological or pathological conditions. However, it remains uncertain whether iron deficiency inhibits the activation of quiescent mesenchymal stem cells (MSCs) by affecting histone demethylase activity. In our study, we identified KDM4D as a key player in the activation of quiescent MSCs. Under conditions of iron deficiency, the H3K9me3 demethylase activity of KDM4D significantly decreased. This alteration resulted in increased heterochromatin with H3K9me3 near the PIK3R3 promoter, suppressing PIK3R3 expression and subsequently inhibiting the activation of quiescent MSCs via the PI3K-Akt-Foxo1 pathway. Iron-deficient mice displayed significantly impaired bone marrow MSCs activation and decreased bone mass compared to normal mice. Modulating the PI3K-Akt-Foxo1 pathway could reverse iron deficiency-induced bone loss.