RNF217 regulates iron homeostasis through its E3 ubiquitin ligase activity by modulating ferroportin degradation

Erythropoietin enhances iron bioavailability in HepG2 cells by downregulating hepcidin through mTOR, C/EBPα and HIF-1α

The regulation of iron (Fe) levels is essential to maintain an adequate supply for erythropoiesis, among other processes, and to avoid possible toxicity. The liver-produced peptide hepcidin is regarded as the main regulator of Fe absorption in enterocytes and release from hepatocytes and macrophages, as it impairs Fe export through ferroportin. The glycoprotein erythropoietin (Epo) drives erythroid progenitor survival and differentiation in the bone marrow, and has been linked to the mobilization of Fe reserves necessary for hemoglobin production. Herein we show that Epo inhibits hepcidin expression directly in the HepG2 hepatic cell line, thus leading to a decrease in intracellular Fe levels. Such inhibition was dependent on the Epo receptor-associated kinase JAK2, as well as on the PI3K/AKT/mTOR pathway, which regulates nutrient homeostasis. Epo was also found to decrease binding of the C/EBP-α transcription factor to the hepcidin promoter, which could be attributed to an increased expression of its inhibitor CHOP. Epo did not only hinder the stimulating effect of C/EBP-α on hepcidin transcription, but also favored hepcidin inhibition by HIF-1α, by increasing is nuclear translocation as well as its protein levels. Moreover, in assays with the inhibitor genistein, this transcription factor was found necessary for Epo-induced hepcidin suppression. Our findings support the involvement of the PI3K/AKT/mTOR pathway in the regulation of Fe levels by Epo, and highlight the contrasting roles of the C/EBP-α and HIF-1α transcription factors as downstream effectors of the cytokine in this process.

Targeting PKCα alleviates iron overload in diabetes and hemochromatosis through the inhibition of ferroportin

ABSTRACT

Ferroportin (Fpn) is the only iron exporter, playing a crucial role in systemic iron homeostasis. Fpn is negatively regulated by its ligand hepcidin, but other potential regulators in physiological and disease conditions remain poorly understood. Diabetes is a metabolic disorder that develops body iron loading with unknown mechanisms. By using diabetic mouse models and human duodenal specimens, we demonstrated that intestinal Fpn expression was increased in diabetes in a hepcidin-independent manner. Protein kinase C (PKC) is hyperactivated in diabetes. We showed that PKCα was required to sustain baseline Fpn expression and diabetes-induced Fpn upregulation in the enterocytes and macrophages. Knockout of PKCα abolished diabetes-associated iron overload. Mechanistically, activation of PKCα increased the exocytotic trafficking of Fpn and decreased the endocytic trafficking of Fpn in the resting state. Hyperactive PKCα also suppressed hepcidin-induced ubiquitination, internalization, and degradation of Fpn. We further observed that iron loading in the enterocytes and macrophages activated PKCα, acting as a novel mechanism to enhance Fpn-dependent iron efflux. Finally, we demonstrated that the loss-of-function of PKCα and pharmacological inhibition of PKC significantly alleviated hereditary hemochromatosis-associated iron overload. Our study has highlighted, to our knowledge, for the first time, that PKCα is an important positive regulator of Fpn and a new target in the control of iron homeostasis.

The Role of Iron in Intestinal Mucus: Perspectives from Both the Host and Gut Microbiota

Although research on the role of iron in host immunity has a history spanning decades, it is only relatively recently that attention has been directed toward the biological effects of iron on the intestinal mucus layer, prompted by an evolving understanding of the role of this material in immune defence. The mucus layer, secreted by intestinal goblet cells, covers the intestinal epithelium, and given its unique location, interactions between the host and gut microbiota, as well as among constituent microbiota, occur frequently within the mucus layer. Iron, being an essential nutrient for the vast majority of life forms, regulates immune responses from both the host and microbial perspectives. In this review, we summarize the iron metabolism of both the host and gut microbiota, and describe how iron contributes to intestinal mucosal homeostasis via the intestinal mucus layer with respect to both host and constituent gut microbiota. The findings described herein offer a new perspective on iron-mediated intestinal mucosal barrier function.

A promising new approach to cancer therapy: Manipulate ferroptosis by hijacking endogenous iron

Ferroptosis, a form of regulated cell death characterized by iron-dependent phospholipid peroxidation, has emerged as a focal point in the field of cancer therapy. Compared with other cell death modes such as apoptosis and necrosis, ferroptosis exhibits many distinct characteristics in the molecular mechanisms and cell morphology, offering a promising avenue for combating cancers that are resistant to conventional therapeutic modalities. In light of the serious side effects associated with current Fenton-modulating ferroptosis therapies utilizing exogenous iron-based inorganic nanomaterials, hijacking endogenous iron could serve as an effective alternative strategy to trigger ferroptosis through targeting cellular iron regulatory mechanisms. A better understanding of the underlying iron regulatory mechanism in the process of ferroptosis has shed light on the current findings of endogenous ferroptosis-based nanomedicine strategies for cancer therapy. Here in this review article, we provide a comprehensive discussion on the regulatory network of iron metabolism and its pivotal role in ferroptosis, and present recent updates on the application of nanoparticles endowed with the ability to hijack endogenous iron for ferroptosis. We envision that the insights in the study may expedite the development and translation of endogenous ferroptosis-based nanomedicines for effective cancer treatment.

Protein modification and degradation in ferroptosis

Ferroptosis is a form of iron-related oxidative cell death governed by an integrated redox system, encompassing pro-oxidative proteins and antioxidative proteins. These proteins undergo precise control through diverse post-translational modifications, including ubiquitination, phosphorylation, acetylation, O-GlcNAcylation, SUMOylation, methylation, N-myristoylation, palmitoylation, and oxidative modification. These modifications play pivotal roles in regulating protein stability, activity, localization, and interactions, ultimately influencing both the buildup of iron and lipid peroxidation. In mammalian cells, regulators of ferroptosis typically undergo degradation via two principal pathways: the ubiquitin-proteasome system, which handles the majority of protein degradation, and autophagy, primarily targeting long-lived or aggregated proteins. This comprehensive review aims to summarize recent advances in the post-translational modification and degradation of proteins linked to ferroptosis. It also discusses strategies for modulating ferroptosis through protein modification and degradation systems, providing new insights into potential therapeutic applications for both cancer and non-neoplastic diseases.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

Asiatic acid ameliorates doxorubicin-induced cardiotoxicity by promoting FPN-mediated iron export and inhibiting ferroptosis

Doxorubicin (DOX), a common chemotherapeutic agent in cancer therapy, is accompanied by pronounced cardiotoxicity. Ferroptosis has been implicated in the pathogenesis and therapeutics of DOX-induced cardiotoxicity (DIC). Asiatic acid (AA), a pentacyclic triterpene from the Chinese medicinal herb Centella asiatica, displays antioxidant, anti-inflammatory, and antiapoptotic activities. In this study, we investigated the beneficial effects of AA against DOX-induced ferroptosis and cardiotoxicity and the underlying mechanisms. A chronic DIC model was established by challenging mice with DOX (5 mg/kg, i.p.) once per week for 4 weeks. Concurrent with DOX insult, the mice were administered AA (25 mg·kg-1·d-1, i.g.). Cardiac function and mechanical properties of isolated cardiomyocytes were evaluated at the end of treatment. We showed that AA administration preserved cardiac function, significantly reduced cardiac injury, and improved cardiomyocyte contractile function in DIC mice. The beneficial effects of AA were causally linked to the inhibition of DOX-induced ferroptosis both in vivo and in vitro. We revealed that AA attenuated DOX-induced iron accumulation in HL-1 cells by increasing FPN-mediated iron export, in a Nrf2-dependent manner. AA upregulated Nrf2 expression and promoted Nrf2 nuclear translocation in DOX-treated HL-1 cells. Moreover, AA-offered benefits against DOX-induced cardiac dysfunction and ferroptosis were abolished by Nrf2 inhibitor ML385 (30 mg·kg-1·d-1, i.p.) administrated 30 min before AA in DIC mice. Our data favor that AA promotes FPN-mediated iron export to inhibit iron overload and ferroptosis in DIC, suggesting its therapeutic potential in the treatment of DIC.

Ferroptosis mechanism and Alzheimer's disease

Regulated cell death is a genetically determined form of programmed cell death that commonly occurs during the development of living organisms. This process plays a crucial role in modulating homeostasis and is evolutionarily conserved across a diverse range of living organisms. Ferroptosis is a classic regulatory mode of cell death. Extensive studies of regulatory cell death in Alzheimer's disease have yielded increasing evidence that ferroptosis is closely related to the occurrence, development, and prognosis of Alzheimer's disease. This review summarizes the molecular mechanisms of ferroptosis and recent research advances in the role of ferroptosis in Alzheimer's disease. Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for Alzheimer's disease.

Acupuncture improve proteinuria in diabetic kidney disease rats by inhibiting ferroptosis and epithelial-mesenchymal transition

Objective

To explore the mechanism of acupuncture to relieve diabetic proteinuria in Diabetic Kidney Disease (DKD).

Methods

A total of 10 male Sprague-Dawley rats were randomly selected as the negative control group (NC), and a further 30 rats were fed a high-fat diet (HFD) and intraperitoneal streptozotocin (STZ). The DKD model rats in the model group (DKD) and the acupuncture group (DKD + Acu) were randomly assigned. After 4 weeks of intervention, collected urine, peripheral blood, and renal tissues from all rats, and assessed blood urea nitrogen, serum creatinine, triglyceride, 24-h urine protein quantification, and blood glucose, left kidney weight, kidney body ratio index, then observe changes in renal histology in the rats. The renal cortex tissues of three rats from each group were sent for transcriptomic analysis. According to the results of transcriptomic analysis, various kits were used to detect SOD, MDA, GSH, GSH-px, and iron concentration. The expression levels of GPX4 and System Xc-, members of the antioxidative stress pathway, and TfR 1, SLC39A14, FTH 1, and SLC40A1, involved in iron metabolism, in the kidney tissues were measured by western blotting and reverse transcription-quantitative PCR. The expression of mesenchymal phenotype markers and podocyte-specific markers were evaluated by immunofluorescence.

Results

Acupuncture promoted the levels of GSH, GSH-px, and SOD, decreased the level of MDA (P < 0.05), promoted the expression of GPX4 and System Xc- (P < 0.05), decreased the expression of TfR1 and SLC39A14 (P < 0.01), and increased the expression of FTH 1 and SLC40A1 (P < 0.05), inhibited the expression of TGF-β1, desmin, FSP-1, and α-SMA (P < 0.05), promoted the expression of Nephrin, Podocin, and CD2AP (P < 0.05).

Conclusion

Improving the ability of podocytes to prevent oxidative stress and restoring iron ion homeostasis, can improve Ferroptosis and block epithelial-mesenchymal transition, improve podocyte injury, restore filtration function, and reduce proteinuria in DKD rats.

Mechanism of ferroptosis regulating ischemic stroke and pharmacologically inhibiting ferroptosis in treatment of ischemic stroke

Ferroptosis is a newly discovered form of programmed cell death that is non-caspase-dependent and is characterized by the production of lethal levels of iron-dependent lipid reactive oxygen species (ROS). In recent years, ferroptosis has attracted great interest in the field of cerebral infarction because it differs morphologically, physiologically, and genetically from other forms of cell death such as necrosis, apoptosis, autophagy, and pyroptosis. In addition, ROS is considered to be an important prognostic factor for ischemic stroke, making it a promising target for stroke treatment. This paper summarizes the induction and defense mechanisms associated with ferroptosis, and explores potential treatment strategies for ischemic stroke in order to lay the groundwork for the development of new neuroprotective drugs.

Rocaglamide regulates iron homeostasis by suppressing hepcidin expression

The anemia of inflammation (AI) is characterized by the presence of inflammation and abnormal elevation of hepcidin. Accumulating evidence has proved that Rocaglamide (RocA) was involved in inflammation regulation. Nevertheless, the role of RocA in AI, especially in iron metabolism, has not been investigated, and its underlying mechanism remains elusive. Here, we demonstrated that RocA dramatically suppressed the elevation of hepcidin and ferritin in LPS-treated mice cell line RAW264.7 and peritoneal macrophages. In vivo study showed that RocA can restrain the depletion of serum iron (SI) and transferrin (Tf) saturation caused by LPS. Further investigation showed that RocA suppressed the upregulation of hepcidin mRNA and downregulation of Fpn1 protein expression in the spleen and liver of LPS-treated mice. Mechanistically, this effect was attributed to RocA's ability to inhibit the IL-6/STAT3 pathway, resulting in the suppression of hepcidin mRNA and subsequent increase in Fpn1 and TfR1 expression in LPS-treated macrophages. Moreover, RocA inhibited the elevation of the cellular labile iron pool (LIP) and reactive oxygen species (ROS) induced by LPS in RAW264.7 cells. These findings reveal a pivotal mechanism underlying the roles of RocA in modulating iron homeostasis and also provide a candidate natural product on alleviating AI.

Additive and Dominance Genome-Wide Association Studies Reveal the Genetic Basis of Heterosis Related to Growth Traits of Duhua Hybrid Pigs

Heterosis has been extensively used for pig genetic breeding and production, but the genetic basis of heterosis remains largely elusive. Crossbreeding between commercial and native breeds provides a good model to parse the genetic basis of heterosis. This study uses Duhua hybrid pigs, a crossbreed of Duroc and Liangguang small spotted pigs, as materials to explore the genetic basis underlying heterosis related to growth traits at the genomic level. The mid-parent heterosis (MPH) analysis showed heterosis of this Duhua offspring on growth traits. In this study, we examined the impact of additive and dominance effects on 100 AGE (age adjusted to 100 kg) and 100 BF (backfat thickness adjusted to 100 kg) of Duhua hybrid pigs. Meanwhile, we successfully identified SNPs associated with growth traits through both additive and dominance GWASs (genome-wide association studies). These findings will facilitate the subsequent in-depth studies of heterosis in the growth traits of Duhua pigs.

Mendelian Randomization Analysis of Systemic Iron Status and Risk of Different Types of Kidney Disease

With rapid increases in incidence, diverse subtypes, and complicated etiologies, kidney disease remains a global public health problem. Iron, as an essential trace element, has pleiotropic effects on renal function and the progression of kidney diseases. A two-sample Mendelian randomization (MR) analysis was implemented to determine the potential causal effects between systemic iron status on different kidney diseases. Systemic iron status was represented by four iron-related biomarkers: serum iron, ferritin, transferrin saturation (TfSat), and total iron binding capacity (TIBC). For systemic iron status, 163,511, 246,139, 131,471, and 135,430 individuals were included in the genome-wide association study (GWAS) of serum iron, ferritin, TfSat, and TIBC, respectively. For kidney diseases, 653,143 individuals (15,658 cases and 637,485 controls), 657,076 individuals (8160 cases and 648,916 controls), and 659,320 individuals (10,404 cases and 648,916 controls) were included for immunoglobulin A nephropathy (IgAN), acute kidney disease (AKD), and chronic kidney disease (CKD), respectively. Our MR results showed that increased serum iron [odds ratio (OR): 1.10; 95% confidence interval (95% CI): 1.04, 1.16; p < 0.0042], ferritin (OR: 1.30; 95% CI: 1.14, 1.48; p < 0.0042), and TfSat (OR: 1.07; 95% CI: 1.04, 1.11; p < 0.0042)] and decreased TIBC (OR: 0.92; 95% CI: 0.88, 0.97; p < 0.0042) were associated with elevated IgAN risk. However, no significant associations were found between systemic iron status and AKD or CKD. In our MR study, the genetic evidence supports elevated systemic iron status as a causal effect on IgAN, which suggests a potential protective effect of iron chelation on IgAN patients.

STL Inhibited Angiogenesis of DPSCs Through Depressing Mitochondrial Respiration by Enhancing RNF217

Angiogenesis is the determining factor during dental pulp regeneration. Six-twelve leukemia (STL) is identified as a key regulatory factor on the biological function of dental pulp stem cells (DPSCs) under hypoxic conditions, but its effect on angiogenesis is unclear. Co-culture of DPSCs and human umbilical vein endothelial cells (HUVECs) is used to detect tubule formation ability in vitro and the angiogenesis ability in vivo. RNA-seq and bioinformatic analyses are performed to screen differentially expressed genes. Seahorse Cell Mito Stress Test is proceeded to exam mitochondrial respiration. STL decreased tubule formation and mitochondrial respiration of DPSCs in vitro and restrained the number of blood vessels and the expression of VEGF in new formed tissue in vivo. Furthermore, pretreating STL-depleted DPSCs with rotenone, a mitochondrial respiration inhibitor, counteracted the promoting effect of STL knockdown on tubule formation. Then, RNA-seq and bioinformatic analyses identified some angiogenesis relevant genes and pathways in STL-depleted DPSCs. And STL enhanced expression of mRNA-ring finger protein 217 (RNF217), which inhibited the tubule formation and mitochondrial respiration of DPSCs. STL inhibited the angiogenesis of DPSCs through depressing mitochondrial respiration by enhancing RNF217, indicating that STL is a potential target for angiogenesis of DPSCs.

E3 ligases and DUBs target ferroptosis: A potential therapeutic strategy for neurodegenerative diseases

Ferroptosis is a form of cell death mediated by iron and lipid peroxidation (LPO). Recent studies have provided compelling evidence to support the involvement of ferroptosis in the pathogenesis of various neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD). Therefore, understanding the mechanisms that regulate ferroptosis in NDDs may improve disease management. Ferroptosis is regulated by multiple mechanisms, and different degradation pathways, including autophagy and the ubiquitinproteasome system (UPS), orchestrate the complex ferroptosis response by directly or indirectly regulating iron accumulation or lipid peroxidation. Ubiquitination plays a crucial role as a protein posttranslational modification in driving ferroptosis. Notably, E3 ubiquitin ligases (E3s) and deubiquitinating enzymes (DUBs) are key enzymes in the ubiquitin system, and their dysregulation is closely linked to the progression of NDDs. A growing body of evidence highlights the role of ubiquitin system enzymes in regulating ferroptosis sensitivity. However, reports on the interaction between ferroptosis and ubiquitin signaling in NDDs are scarce. In this review, we first provide a brief overview of the biological processes and roles of the UPS, summarize the core molecular mechanisms and potential biological functions of ferroptosis, and explore the pathophysiological relevance and therapeutic implications of ferroptosis in NDDs. In addition, reviewing the roles of E3s and DUBs in regulating ferroptosis in NDDs aims to provide new insights and strategies for the treatment of NDDs. These include E3- and DUB-targeted drugs and ferroptosis inhibitors, which can be used to prevent and ameliorate the progression of NDDs.

International consensus guidelines for the definition, detection, and interpretation of autophagy-dependent ferroptosis

Macroautophagy/autophagy is a complex degradation process with a dual role in cell death that is influenced by the cell types that are involved and the stressors they are exposed to. Ferroptosis is an iron-dependent oxidative form of cell death characterized by unrestricted lipid peroxidation in the context of heterogeneous and plastic mechanisms. Recent studies have shed light on the involvement of specific types of autophagy (e.g. ferritinophagy, lipophagy, and clockophagy) in initiating or executing ferroptotic cell death through the selective degradation of anti-injury proteins or organelles. Conversely, other forms of selective autophagy (e.g. reticulophagy and lysophagy) enhance the cellular defense against ferroptotic damage. Dysregulated autophagy-dependent ferroptosis has implications for a diverse range of pathological conditions. This review aims to present an updated definition of autophagy-dependent ferroptosis, discuss influential substrates and receptors, outline experimental methods, and propose guidelines for interpreting the results.Abbreviation: 3-MA:3-methyladenine; 4HNE: 4-hydroxynonenal; ACD: accidentalcell death; ADF: autophagy-dependentferroptosis; ARE: antioxidant response element; BH2:dihydrobiopterin; BH4: tetrahydrobiopterin; BMDMs: bonemarrow-derived macrophages; CMA: chaperone-mediated autophagy; CQ:chloroquine; DAMPs: danger/damage-associated molecular patterns; EMT,epithelial-mesenchymal transition; EPR: electronparamagnetic resonance; ER, endoplasmic reticulum; FRET: Försterresonance energy transfer; GFP: green fluorescent protein;GSH: glutathione;IF: immunofluorescence; IHC: immunohistochemistry; IOP, intraocularpressure; IRI: ischemia-reperfusion injury; LAA: linoleamide alkyne;MDA: malondialdehyde; PGSK: Phen Green™ SK;RCD: regulatedcell death; PUFAs: polyunsaturated fatty acids; RFP: red fluorescentprotein;ROS: reactive oxygen species; TBA: thiobarbituricacid; TBARS: thiobarbituric acid reactive substances; TEM:transmission electron microscopy.

Recent advancements in nanomaterial-mediated ferroptosis-induced cancer therapy: Importance of molecular dynamics and novel strategies

Ferroptosis is a novel type of controlled cell death resulting from an imbalance between oxidative harm and protective mechanisms, demonstrating significant potential in combating cancer. It differs from other forms of cell death, such as apoptosis and necrosis. Molecular therapeutics have hard time playing the long-acting role of ferroptosis induction due to their limited water solubility, low cell targeting capacity, and quick metabolism in vivo. To this end, small molecule inducers based on biological factors have long been used as strategy to induce cell death. Research into ferroptosis and advancements in nanotechnology have led to the discovery that nanomaterials are superior to biological medications in triggering ferroptosis. Nanomaterials derived from iron can enhance ferroptosis induction by directly releasing large quantities of iron and increasing cell ROS levels. Moreover, utilizing nanomaterials to promote programmed cell death minimizes the probability of unfavorable effects induced by mutations in cancer-associated genes such as RAS and TP53. Taken together, this review summarizes the molecular mechanisms involved in ferroptosis along with the classification of ferroptosis induction. It also emphasized the importance of cell organelles in the control of ferroptosis in cancer therapy. The nanomaterials that trigger ferroptosis are categorized and explained. Iron-based and noniron-based nanomaterials with their characterization at the molecular and cellular levels have been explored, which will be useful for inducing ferroptosis that leads to reduced tumor growth. Within this framework, we offer a synopsis, which traverses the well-established mechanism of ferroptosis and offers practical suggestions for the design and therapeutic use of nanomaterials.

Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

Microplastics (MPs) and nanoplastics (NPs) have become hazardous materials due to the massive amount of plastic waste and disposable masks, but their specific health effects remain uncertain. In this study, fluorescence-labeled polystyrene NPs (PS-NPs) were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in vivo. Interestingly, whole-body imaging found that PS-NPs accumulated in the testes of mice. Therefore, the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice, and their mechanisms, were investigated. After oral exposure to PS-NPs, their spermatogenesis was affected and the spermatogenic cells were damaged. The spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing (RNA-seq) to determine the toxic mechanisms; a ferroptosis pathway was found after PS-NP exposure. The phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1 (Fer-1), and it was also found that nuclear factor erythroid 2-related factor 2 (Nrf2) played an important role in spermatogenic cell ferroptosis induced by PS-NPs. Finally, it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive toxicity. This study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

Mechanistic insights into the ameliorative effects of Xianglianhuazhuo formula on chronic atrophic gastritis through ferroptosis mediated by YY1/miR-320a/TFRC signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Xianglianhuazhuo formula (XLHZ) has a potential therapeutic effect on chronic atrophic gastritis (CAG). However, the specific molecular mechanism remains unclear.

AIM OF THE STUDY

To evaluate the effect of XLHZ on CAG in vitro and in vivo and its potential mechanisms.

METHODS

A rat model of CAG was established using a composite modeling method, and the pathological changes and ultrastructure of gastric mucosa were observed. YY1/miR-320a/TFRC and ferroptosis-related molecules were detected. An MNNG-induced gastric epithelial cell model was established in vitro to evaluate the inhibitory effect of XLHZ on cell ferroptosis by observing cell proliferation, migration, invasion, apoptosis, and molecules related to ferroptosis. The specific mechanism of action of XLHZ in treating CAG was elucidated by silencing or overexpression of targets.

RESULTS

In vivo experiments showed that XLHZ could improve the pathological status and ultrastructure of gastric mucosa and inhibit ferroptosis by regulating the YY1/miR-320a/TFRC signaling pathway. The results in vitro demonstrated that transfection of miR-320a mimics inhibited cell proliferation, migration, and invasion while promoting cell apoptosis. MiR-320a targeted TFRC and inhibited ferroptosis. Overexpression of TFRC reversed the inhibitory effect of miR-320a overexpression on cell proliferation. The effect of XLHZ was consistent with that of miR-320a. YY1 targeted miR-320a, and its overexpression promoted ferroptosis.

CONCLUSION

XLHZ inhibited ferroptosis by regulating the YY1/miR-320a/TFRC signaling pathway, ultimately impeding the progression of CAG.

Ferroptosis mechanisms and its novel potential therapeutic targets for DLBCL

Diffuse large B-cell lymphoma (DLBCL), a heterogeneous lymphoid malignancy, poses a significant threat to human health. The standard therapeutic regimen for patients with DLBCL is rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), with a typical cure rate of 50-70%. However, some patients either relapse after complete remission (CR) or exhibit resistance to R-CHOP treatment. Therefore, novel therapeutic approaches are imperative for managing high-risk or refractory DLBCL. Ferroptosis is driven by iron-dependent phospholipid peroxidation, a process that relies on the transition metal iron, reactive oxygen species (ROS), and phospholipids containing polyunsaturated fatty acids-containing phospholipids (PUFA-PLs). Research indicates that ferroptosis is implicated in various carcinogenic and anticancer pathways. Several hematological disorders exhibit heightened sensitivity to cell death induced by ferroptosis. DLBCL cells, in particular, demonstrate an increased demand for iron and an upregulation in the expression of fatty acid synthase. Additionally, there exists a correlation between ferroptosis-associated genes and the prognosis of DLBCL. Therefore, ferroptosis may be a promising novel target for DLBCL therapy. In this review, we elucidate ferroptosis mechanisms, its role in DLBCL, and the potential therapeutic targets in DLBCL. This review offers novel insights into the application of ferroptosis in treatment strategies for DLBCL.

Sestrin2 ameliorates diabetic retinopathy by regulating autophagy and ferroptosis

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes. The aim of this study was to explore the effect of Sestrin2 on DR through the regulation of autophagy and ferroptosis levels and its mechanism. In vitro and in vivo DR models were established by high glucose (HG) and streptozotocin (STZ) induction of ARPE-19 human retinal pigment epithelial cells and C57BL/6 mice, respectively. In this study, we demonstrated that after HG treatment, the activity of ARPE-19 cells was decreased, the apoptosis rate was increased, endoplasmic reticulum (ER) stress was activated, autophagy levels were decreased, and ferroptosis levels were increased. Overexpression of Sestrin2 enhanced cell viability, reduced apoptosis and ferroptosis, and enhanced autophagy. However, the effect of overexpression of Sestrin2 was attenuated after the addition of the STAT3 phosphorylation activator Colivelin TFA (C-TFA), the mTOR pathway activator MHY1485 or the autophagy inhibitor 3-methyladenine (3-MA). In addition, the effect of Sestrin2 knockdown on cells was opposite to the effect of overexpression of Sestrin2, while the effect of Sestrin2 knockdown was attenuated after treatment with the ER stress inhibitor 4-phenylbutyric acid (4-PBA). Animal experiments also confirmed the results of cell experiments and attenuated the effects of overexpression of Sestrin2 after injection of the ferroptosis activators erastin or 3-MA. Our study revealed that Sestrin2 inhibits ferroptosis by inhibiting STAT3 phosphorylation and ER stress and promoting autophagy levels, thereby alleviating DR.

Polyamine-mediated ferroptosis amplification acts as a targetable vulnerability in cancer

Targeting ferroptosis, an iron-dependent form of regulated cell death triggered by the lethal overload of lipid peroxides, in cancer therapy is impeded by our limited understanding of the intersection of tumour's metabolic feature and ferroptosis vulnerability. In the present study, arginine is identified as a ferroptotic promoter using a metabolites library. This effect is mainly achieved through arginine's conversion to polyamines, which exerts their potent ferroptosis-promoting property in an H2O2-dependent manner. Notably, the expression of ornithine decarboxylase 1 (ODC1), the critical enzyme catalysing polyamine synthesis, is significantly activated by the ferroptosis signal--iron overload--through WNT/MYC signalling, as well as the subsequent elevated polyamine synthesis, thus forming a ferroptosis-iron overload-WNT/MYC-ODC1-polyamine-H2O2 positive feedback loop that amplifies ferroptosis. Meanwhile, we notice that ferroptotic cells release enhanced polyamine-containing extracellular vesicles into the microenvironment, thereby further sensitizing neighbouring cells to ferroptosis and accelerating the "spread" of ferroptosis in the tumour region. Besides, polyamine supplementation also sensitizes cancer cells or xenograft tumours to radiotherapy or chemotherapy through inducing ferroptosis. Considering that cancer cells are often characterized by elevated intracellular polyamine pools, our results indicate that polyamine metabolism exposes a targetable vulnerability to ferroptosis and represents an exciting opportunity for therapeutic strategies for cancer.

Lactate administration improves laboratory parameters in murine models of iron overload

ABSTRACT

Current iron overload therapeutics have inherent drawbacks including perpetuated low hepcidin. Here, we unveiled that lactate, a potent hepcidin agonist, effectively reduced serum and hepatic iron levels in mouse models of iron overload with an improved erythropoiesis in β-thalassemic mice.

Intracellular Regulation Limits the Response of Intestinal Ferroportin to Iron Status in Suckling Rats

SCOPE

Iron status is regulated via iron absorption as there is no active iron excretion. Divalent metal-ion transporter-1 (DMT1) and ferroportin (FPN) are two key proteins vital for iron absorption, but the regulation of them in suckling mammals differs from that in adults. This study aims to explore regulation of iron transporters under different iron conditions during suckling.

METHODS AND RESULTS

This study developed suckling rats under different iron conditions. Unexpectedly, unchanged FPN at different iron status are detected. Since FPN is the only known iron exporter for mammals, unchanged FPN limits iron exported into blood during suckling. Thus, factors regulating FPN at transcriptional, post-transcriptional, and post-translational levels are detected. Results showed that Fpn mRNA is upregulated, while micro RNA-485(miR-485) which could silence Fpn mRNA is upregulated at low iron status limiting translation of Fpn mRNA. Besides, serum hepcidin and liver Hamp mRNA are upregulated, but ring finger protein 217( Rnf217) mRNA remained unchanged at high iron status leading to FPN not downregulated as adults.

CONCLUSIONS

Overall, this study indicates that translational regulation limits intestinal FPN protein response to iron deficiency and Rnf217 cannot effectively mediate the degradation of FPN at high iron status, which provides a reference for maintaining iron homeostasis during suckling.

Research progress on and molecular mechanism of vacuum sealing drainage in the treatment of diabetic foot ulcers

Diabetic foot ulcers (DFUs) are common chronic wounds and a common complication of diabetes. The foot is the main site of diabetic ulcers, which involve small and medium-sized arteries, peripheral nerves, and microcirculation, among others. DFUs are prone to coinfections and affect many diabetic patients. In recent years, interdisciplinary research combining medicine and material science has been increasing and has achieved significant clinical therapeutic effects, and the application of vacuum sealing drainage (VSD) in the treatment of DFUs is a typical representative of this progress, but the mechanism of action remains unclear. In this review, we integrated bioinformatics and literature and found that ferroptosis is an important signaling pathway through which VSD promotes the healing of DFUs and that System Xc-GSH-GPX4 and NAD(P)H-CoQ10-FSP1 are important axes in this signaling pathway, and we speculate that VSD is most likely to inhibit ferroptosis to promote DFU healing through the above axes. In addition, we found that some classical pathways, such as the TNF, NF-κB, and Wnt/β-catenin pathways, are also involved in the VSD-mediated promotion of DFU healing. We also compiled and reviewed the progress from clinical studies on VSD, and this information provides a reference for the study of VSD in the treatment of DFUs.

Tumor iron homeostasis and immune regulation

Abnormal iron metabolism has long been regarded as a key metabolic hallmark of cancer. As a critical cofactor, iron contributes to tumor progression by participating in various processes such as mitochondrial electron transport, gene regulation, and DNA synthesis or repair. Although the role of iron in tumor cells has been widely studied, recent studies have uncovered the interplay of iron metabolism between tumor cells and immune cells, which may affect both innate and adaptive immune responses. In this review, we discuss the current understanding of the regulatory networks of iron metabolism between cancer cells and immune cells and how they contribute to antitumor immunity, and we analyze potential therapeutics targeting iron metabolism. Also, we highlight several key challenges and describe potential therapeutic approaches for future investigations.

Mechanisms controlling cellular and systemic iron homeostasis

In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.

Protective effect of Angelica sinensis polysaccharide on pregnant rats suffering from iron deficiency anemia via regulation of the hepcidin-FPN1 axis

Iron deficiency anemia (IDA) is a common micronutrient deficiency among pregnant women with deleterious maternal and fetal outcomes. Angelica sinensis polysaccharide (ASP) has been shown to reduce hepcidin expression in IDA rats. However, the role of ASP in the treatment of IDA during pregnancy and its potential mechanisms have not been investigated. Moreover, the effect of ASP on duodenal iron absorption is not clear. The aim of this study was to investigate the preventive efficacy of ASP against IDA during pregnancy and clarify the underlying mechanisms. Our results showed that ASP improved maternal hematological parameters, increased serum iron, maternal tissue iron, and fetal liver iron content, and improved pregnancy outcomes. Additionally, ASP combated oxidative stress caused by iron deficiency by improving the body's antioxidant capacity. Western blot results demonstrated that ASP downregulated hepcidin expression by blocking the BMP6/SMAD4, JAK2/STAT3 and TfR2/HFE signaling pathways, which in turn increased the expression of FPN1 in the liver, spleen, and duodenum and promoted iron cycling in the body. Furthermore, ASP increased the expression of DMT1 and Dcytb in the duodenum, thereby facilitating duodenal iron uptake. Our results suggest that ASP is a potential agent for the prevention and treatment of IDA during pregnancy.

Nutritional Modulation of Hepcidin in the Treatment of Various Anemic States

Twenty years after its discovery, hepcidin is still considered the main regulator of iron homeostasis in humans. The increase in hepcidin expression drastically blocks the flow of iron, which can come from one's diet, from iron stores, and from erythrophagocytosis. Many anemic conditions are caused by non-physiologic increases in hepcidin. The sequestration of iron in the intestine and in other tissues poses worrying premises in view of discoveries about the mechanisms of ferroptosis. The nutritional treatment of these anemic states cannot ignore the nutritional modulation of hepcidin, in addition to the bioavailability of iron. This work aims to describe and summarize the few findings about the role of hepcidin in anemic diseases and ferroptosis, as well as the modulation of hepcidin levels by diet and nutrients.

Global research landscape on the crosstalk between ferroptosis and musculoskeletal diseases: A bibliometric and visualized analysis

Over the past 11 years, mounting evidence has suggested a significant association between ferroptosis and the development and progression of musculoskeletal (MSK) diseases, such as osteoporosis and osteoarthritis. However, a comprehensive bibliometric analysis summarizing the relationship between ferroptosis and MSK diseases is currently lacking. The present study collected articles and reviews on the topic of ferroptosis in MSK diseases. The data were collected from January 1st, 2012 to June 30th, 2023 by screening the Web of Science database. Various tools, including VOSviewer, CiteSpace, Pajek, the R package, and others, were used to conduct bibliometric and visualization analyses. Notably, China, the USA, and Italy emerged as primary contributors, jointly accounting for over 80 % of published documents, thereby shaping research in this domain. Among the diverse institutions, Shanghai Jiao Tong University, Soochow University, and Huazhong University of Science and Technology displayed the highest productivity levels. The most prolific authors include Sun Kai, Shang Peng, and Jing Xingzhi. Oxidative Medicine and Cellular Longevity stood out with the largest number of publications in this area. The five most significant disorders in this field are bone fractures, osteosarcoma, bone neoplasms, joint diseases, and osteoporotic fractures. This study represents an inaugural comprehensive bibliometric analysis, presenting a holistic view of the knowledge framework and developmental patterns in ferroptosis concerning MSK diseases over the previous eleven years. This information can aid researchers in acquiring a thorough grasp of this domain and offer invaluable insights for forthcoming explorations.

Targeting PKC alleviates iron overload in diabetes and hemochromatosis

Diabetes is one of the most prevalent chronic diseases worldwide. Iron overload increases the incidence of diabetes and aggravates diabetic complications that cause mortality. Reciprocally, diabetes potentially promotes body iron loading, but the mechanism remains not well understood. In this study, we demonstrated systemic iron excess and the upregulation of iron exporter ferroportin (Fpn) in the enterocytes and macrophages of multiple diabetic mouse models. Increased Fpn expression and iron efflux was also seen in the enterocytes of type 2 diabetic human patients. We further showed that protein kinase C (PKC), which is activated in hyperglycemia, was responsible for the sustained membrane expression of Fpn in physiological and in diabetic settings. For the first time, we identified that PKCs were novel binding proteins and positive regulators of Fpn. Mechanistically, hyperactive PKC promoted exocytotic membrane insertion while inhibited the endocytic trafficking of Fpn in the resting state. PKC also protected Fpn from internalization and degradation by its ligand hepcidin dependent on decreased ubiquitination and increased phosphorylation of Fpn. Importantly, the loss-of-function and pharmacological inhibition of PKC alleviated systemic iron overload in diabetes and hemochromatosis. Our study thus highlights PKC as a novel target in the control of systemic iron homeostasis.

Metformin potentiates nephrotoxicity by promoting NETosis in response to renal ferroptosis

Given the rapidly aging population, aging-related diseases are becoming an excessive burden on the global healthcare system. Metformin has been shown to be beneficial to many age-related disorders, as well as increase lifespan in preclinical animal models. During the aging process, kidney function progressively declines. Currently, whether and how metformin protects the kidney remains unclear. In this study, among longevity drugs, including metformin, nicotinamide, resveratrol, rapamycin, and senolytics, we unexpectedly found that metformin, even at low doses, exacerbated experimentally-induced acute kidney injury (AKI) and increased mortality in mice. By single-cell transcriptomics analysis, we found that death of renal parenchymal cells together with an expansion of neutrophils occurs upon metformin treatment after AKI. We identified programmed cell death by ferroptosis in renal parenchymal cells and blocking ferroptosis, or depleting neutrophils protects against metformin-induced nephrotoxicity. Mechanistically, upon induction of AKI, ferroptosis in renal parenchymal cells initiates the migration of neutrophils to the site of injury via the surface receptor CXCR4-bound to metformin-iron-NGAL complex, which results in NETosis aggravated AKI. Finally, we demonstrated that reducing iron showed protective effects on kidney injury, which supports the notion that iron plays an important role in metformin-triggered AKI. Taken together, these findings delineate a novel mechanism underlying metformin-aggravated nephropathy and highlight the mechanistic relationship between iron, ferroptosis, and NETosis in the resulting AKI.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Cardiac iron metabolism during aging - Role of inflammation and proteolysis

Iron is the most abundant trace element in the human body. Since iron can switch between its 2-valent and 3-valent form it is essential in various physiological processes such as energy production, proliferation or DNA synthesis. Especially high metabolic organs such as the heart rely on iron-associated iron-sulfur and heme proteins. However, due to switches in iron oxidation state, iron overload exhibits high toxicity through formation of reactive oxygen species, underlining the importance of balanced iron levels. Growing evidence demonstrates disturbance of this balance during aging. While age-associated cardiovascular diseases are often related to iron deficiency, in physiological aging cardiac iron accumulates. To understand these changes, we focused on inflammation and proteolysis, two hallmarks of aging, and their role in iron metabolism. Via the IL-6-hepcidin axis, inflammation and iron status are strongly connected often resulting in anemia accompanied by infiltration of macrophages. This tight connection between anemia and inflammation highlights the importance of the macrophage iron metabolism during inflammation. Age-related decrease in proteolytic activity additionally affects iron balance due to impaired degradation of iron metabolism proteins. Therefore, this review accentuates alterations in iron metabolism during aging with regards to inflammation and proteolysis to draw attention to their implications and associations.

Emerging roles of ferroptosis in male reproductive diseases

Ferroptosis is a type of programmed cell death mediated by iron-dependent lipid peroxidation that leads to excessive lipid peroxidation in different cells. Ferroptosis is distinct from other forms of cell death and is associated with various diseases. Iron is essential for spermatogenesis and male reproductive function. Therefore, it is not surprising that new evidence supports the role of ferroptosis in testicular injury. Although the molecular mechanism by which ferroptosis induces disease is unknown, several genes and pathways associated with ferroptosis have been linked to testicular dysfunction. In this review, we discuss iron metabolism, ferroptosis, and related regulatory pathways. In addition, we analyze the endogenous and exogenous factors of ferroptosis in terms of iron metabolism and testicular dysfunction, as well as summarize the relationship between ferroptosis and male reproductive dysfunction. Finally, we discuss potential strategies to target ferroptosis for treating male reproductive diseases and provide new directions for preventing male reproductive diseases.

Targeting ferroptosis opens new avenues for the development of novel therapeutics

Ferroptosis is an iron-dependent form of regulated cell death with distinct characteristics, including altered iron homeostasis, reduced defense against oxidative stress, and abnormal lipid peroxidation. Recent studies have provided compelling evidence supporting the notion that ferroptosis plays a key pathogenic role in many diseases such as various cancer types, neurodegenerative disease, diseases involving tissue and/or organ injury, and inflammatory and infectious diseases. Although the precise regulatory networks that underlie ferroptosis are largely unknown, particularly with respect to the initiation and progression of various diseases, ferroptosis is recognized as a bona fide target for the further development of treatment and prevention strategies. Over the past decade, considerable progress has been made in developing pharmacological agonists and antagonists for the treatment of these ferroptosis-related conditions. Here, we provide a detailed overview of our current knowledge regarding ferroptosis, its pathological roles, and its regulation during disease progression. Focusing on the use of chemical tools that target ferroptosis in preclinical studies, we also summarize recent advances in targeting ferroptosis across the growing spectrum of ferroptosis-associated pathogenic conditions. Finally, we discuss new challenges and opportunities for targeting ferroptosis as a potential strategy for treating ferroptosis-related diseases.

TET (Ten-eleven translocation) family proteins: structure, biological functions and applications

Ten-eleven translocation (TET) family proteins (TETs), specifically, TET1, TET2 and TET3, can modify DNA by oxidizing 5-methylcytosine (5mC) iteratively to yield 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxycytosine (5caC), and then two of these intermediates (5fC and 5caC) can be excised and return to unmethylated cytosines by thymine-DNA glycosylase (TDG)-mediated base excision repair. Because DNA methylation and demethylation play an important role in numerous biological processes, including zygote formation, embryogenesis, spatial learning and immune homeostasis, the regulation of TETs functions is complicated, and dysregulation of their functions is implicated in many diseases such as myeloid malignancies. In addition, recent studies have demonstrated that TET2 is able to catalyze the hydroxymethylation of RNA to perform post-transcriptional regulation. Notably, catalytic-independent functions of TETs in certain biological contexts have been identified, further highlighting their multifunctional roles. Interestingly, by reactivating the expression of selected target genes, accumulated evidences support the potential therapeutic use of TETs-based DNA methylation editing tools in disorders associated with epigenetic silencing. In this review, we summarize recent key findings in TETs functions, activity regulators at various levels, technological advances in the detection of 5hmC, the main TETs oxidative product, and TETs emerging applications in epigenetic editing. Furthermore, we discuss existing challenges and future directions in this field.

Iron homeostasis imbalance and ferroptosis in brain diseases

Brain iron homeostasis is maintained through the normal function of blood-brain barrier and iron regulation at the systemic and cellular levels, which is fundamental to normal brain function. Excess iron can catalyze the generation of free radicals through Fenton reactions due to its dual redox state, thus causing oxidative stress. Numerous evidence has indicated brain diseases, especially stroke and neurodegenerative diseases, are closely related to the mechanism of iron homeostasis imbalance in the brain. For one thing, brain diseases promote brain iron accumulation. For another, iron accumulation amplifies damage to the nervous system and exacerbates patients' outcomes. In addition, iron accumulation triggers ferroptosis, a newly discovered iron-dependent type of programmed cell death, which is closely related to neurodegeneration and has received wide attention in recent years. In this context, we outline the mechanism of a normal brain iron metabolism and focus on the current mechanism of the iron homeostasis imbalance in stroke, Alzheimer's disease, and Parkinson's disease. Meanwhile, we also discuss the mechanism of ferroptosis and simultaneously enumerate the newly discovered drugs for iron chelators and ferroptosis inhibitors.

Membrane Transporters Involved in Iron Trafficking: Physiological and Pathological Aspects

Iron is an essential transition metal for its involvement in several crucial biological functions, the most notable being oxygen storage and transport. Due to its high reactivity and potential toxicity, intracellular and extracellular iron levels must be tightly regulated. This is achieved through transport systems that mediate cellular uptake and efflux both at the level of the plasma membrane and on the membranes of lysosomes, endosomes and mitochondria. Among these transport systems, the key players are ferroportin, the only known transporter mediating iron efflux from cells; DMT1, ZIP8 and ZIP14, which on the contrary, mediate iron influx into the cytoplasm, acting on the plasma membrane and on the membranes of lysosomes and endosomes; and mitoferrin, involved in iron transport into the mitochondria for heme synthesis and Fe-S cluster assembly. The focus of this review is to provide an updated view of the physiological role of these membrane proteins and of the pathologies that arise from defects of these transport systems.

Zooming in and out of ferroptosis in human disease

Ferroptosis is defined as an iron-dependent regulated form of cell death driven by lipid peroxidation. In the past decade, it has been implicated in the pathogenesis of various diseases that together involve almost every organ of the body, including various cancers, neurodegenerative diseases, cardiovascular diseases, lung diseases, liver diseases, kidney diseases, endocrine metabolic diseases, iron-overload-related diseases, orthopedic diseases and autoimmune diseases. Understanding the underlying molecular mechanisms of ferroptosis and its regulatory pathways could provide additional strategies for the management of these disease conditions. Indeed, there are an expanding number of studies suggesting that ferroptosis serves as a bona-fide target for the prevention and treatment of these diseases in relevant pre-clinical models. In this review, we summarize the progress in the research into ferroptosis and its regulatory mechanisms in human disease, while providing evidence in support of ferroptosis as a target for the treatment of these diseases. We also discuss our perspectives on the future directions in the targeting of ferroptosis in human disease.

Ferroptosis in colorectal cancer: a future target?

Colorectal cancer (CRC) is the third leading cause of cancer deaths worldwide and is characterised by frequently mutated genes, such as APC, TP53, KRAS and BRAF. The current treatment options of chemotherapy, radiation therapy and surgery are met with challenges such as cancer recurrence, drug resistance, and overt toxicity. CRC therapies exert their efficacy against cancer cells by activating biological pathways that contribute to various forms of regulated cell death (RCD). In 2012, ferroptosis was discovered as an iron-dependent and lipid peroxide-driven form of RCD. Recent studies suggest that therapies which target ferroptosis are promising treatment strategies for CRC. However, a greater understanding of the mechanisms of ferroptosis initiation, propagation, and resistance in CRC is needed. This review provides an overview of recent research in ferroptosis and its potential role as a therapeutic target in CRC. We also propose future research directions that could help to enhance our understanding of ferroptosis in CRC.

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Iron Metabolism in Cardiovascular Disease: Physiology, Mechanisms, and Therapeutic Targets

The cardiovascular system requires iron to maintain its high energy demands and metabolic activity. Iron plays a critical role in oxygen transport and storage, mitochondrial function, and enzyme activity. However, excess iron is also cardiotoxic due to its ability to catalyze the formation of reactive oxygen species and promote oxidative damage. While mammalian cells have several redundant iron import mechanisms, they are equipped with a single iron-exporting protein, which makes the cardiovascular system particularly sensitive to iron overload. As a result, iron levels are tightly regulated at many levels to maintain homeostasis. Iron dysregulation ranges from iron deficiency to iron overload and is seen in many types of cardiovascular disease, including heart failure, myocardial infarction, anthracycline-induced cardiotoxicity, and Friedreich's ataxia. Recently, the use of intravenous iron therapy has been advocated in patients with heart failure and certain criteria for iron deficiency. Here, we provide an overview of systemic and cellular iron homeostasis in the context of cardiovascular physiology, iron deficiency, and iron overload in cardiovascular disease, current therapeutic strategies, and future perspectives.

Anemia of chronic diseases: current state of the problem and perspectives

Anemia of chronic diseases is a condition, that accompanies several chronic conditions, that have inflammation as an underlying cause. The article covers current concepts of pathogenesis, evaluation and treatment of this type of anemia. The new perspectives in the development of investigational methods and treatment are discussed. The new methods of iron deficiency assessment in patients with systemic inflammation are discussed separately.

Hepatic SEL1L-HRD1 ER-associated degradation regulates systemic iron homeostasis via ceruloplasmin

Iron homeostasis is critical for cellular and organismal function and is tightly regulated to prevent toxicity or anemia due to iron excess or deficiency, respectively. However, subcellular regulatory mechanisms of iron remain largely unexplored. Here, we report that SEL1L-HRD1 protein complex of endoplasmic reticulum (ER)-associated degradation (ERAD) in hepatocytes controls systemic iron homeostasis in a ceruloplasmin (CP)-dependent, and ER stress-independent, manner. Mice with hepatocyte-specific Sel1L deficiency exhibit altered basal iron homeostasis and are sensitized to iron deficiency while resistant to iron overload. Proteomics screening for a factor linking ERAD deficiency to altered iron homeostasis identifies CP, a key ferroxidase involved in systemic iron distribution by catalyzing iron oxidation and efflux from tissues. Indeed, CP is highly unstable and a bona fide substrate of SEL1L-HRD1 ERAD. In the absence of ERAD, CP protein accumulates in the ER and is shunted to refolding, leading to elevated secretion. Providing clinical relevance of these findings, SEL1L-HRD1 ERAD is responsible for the degradation of a subset of disease-causing CP mutants, thereby attenuating their pathogenicity. Together, this study uncovers the role of SEL1L-HRD1 ERAD in systemic iron homeostasis and provides insights into protein misfolding-associated proteotoxicity.

The molecular and metabolic landscape of iron and ferroptosis in cardiovascular disease

The maintenance of iron homeostasis is essential for proper cardiac function. A growing body of evidence suggests that iron imbalance is the common denominator in many subtypes of cardiovascular disease. In the past 10 years, ferroptosis, an iron-dependent form of regulated cell death, has become increasingly recognized as an important process that mediates the pathogenesis and progression of numerous cardiovascular diseases, including atherosclerosis, drug-induced heart failure, myocardial ischaemia-reperfusion injury, sepsis-induced cardiomyopathy, arrhythmia and diabetic cardiomyopathy. Therefore, a thorough understanding of the mechanisms involved in the regulation of iron metabolism and ferroptosis in cardiomyocytes might lead to improvements in disease management. In this Review, we summarize the relationship between the metabolic and molecular pathways of iron signalling and ferroptosis in the context of cardiovascular disease. We also discuss the potential targets of ferroptosis in the treatment of cardiovascular disease and describe the current limitations and future directions of these novel treatment targets.

Ferroptosis: A Novel Type of Cell Death in Male Reproduction

Ferroptosis, an iron-dependent type of regulated cell death, is triggered by the accumulation of lethal lipid peroxides. Due to its potential in exploring disease progression and highly targeted therapies, it is still a widely discussed topic nowadays. In recent studies, it was found that ferroptosis was induced when testicular tissue was exposed to some high-risk factors, such as cadmium (Cd), busulfan, and smoking accompanied by a variety of reproductive damage characteristics, including changes in the specific morphology and ferroptosis-related features. In this literature-based review, we summarize the related mechanisms of ferroptosis and elaborate upon its relationship network in the male reproductive system in terms of three significant events: the abnormal iron metabolism, dysregulation of the Cyst(e)ine/GSH/GPX4 axis, and lipid peroxidation. It is meaningful to deeply explore the relationship between ferroptosis and the male reproductive system, which may provide suggestions regarding pristine therapeutic targets and novel drugs.

Ferroptosis in heart failure

With its complicated pathobiology and pathophysiology, heart failure (HF) remains an increasingly prevalent epidemic that threatens global human health. Ferroptosis is a form of regulated cell death characterized by the iron-dependent lethal accumulation of lipid peroxides in the membrane system and is different from other types of cell death such as apoptosis and necrosis. Mounting evidence supports the claim that ferroptosis is mainly regulated by several biological pathways including iron handling, redox homeostasis, and lipid metabolism. Recently, ferroptosis has been identified to play an important role in HF induced by different stimuli such as myocardial infarction, myocardial ischemia reperfusion, chemotherapy, and others. Thus, it is of great significance to deeply explore the role of ferroptosis in HF, which might be a prerequisite to precise drug targets and novel therapeutic strategies based on ferroptosis-related medicine. Here, we review current knowledge on the link between ferroptosis and HF, followed by critical perspectives on the development and progression of ferroptotic signals and cardiac remodeling in HF.