The 5-Lipoxygenase Inhibitor Zileuton Confers Neuroprotection against Glutamate Oxidative Damage by Inhibiting Ferroptosis

Systematic Review of the Therapeutic Role of Apoptotic Inhibitors in Neurodegeneration and Their Potential Use in Schizophrenia

Schizophrenia (SZ) is a deleterious brain disorder affecting cognition, emotion and reality perception. The most widely accepted neurochemical-hypothesis is the imbalance of neurotransmitter-systems. Depleted GABAergic-inhibitory function might produce a regionally-located dopaminergic and glutamatergic-storm in the brain. The dopaminergic-release may underlie the positive psychotic-symptoms while the glutamatergic-release could prompt the primary negative symptoms/cognitive deficits. This may occur due to excessive synaptic-pruning during the neurodevelopmental stages of adolescence/early adulthood. Thus, although SZ is not a neurodegenerative disease, it has been suggested that exaggerated dendritic-apoptosis could explain the limited neuroprogression around its onset. This apoptotic nature of SZ highlights the potential therapeutic action of anti-apoptotic drugs, especially at prodromal stages. If dysregulation of apoptotic mechanisms underlies the molecular basis of SZ, then anti-apoptotic molecules could be a prodromal therapeutic option to halt or prevent SZ. In fact, risk alleles related in apoptotic genes have been recently associated to SZ and shared molecular apoptotic changes are common in the main neurodegenerative disorders and SZ. PRISMA-guidelines were considered. Anti-apoptotic drugs are commonly applied in classic neurodegenerative disorders with promising results. Despite both the apoptotic-hallmarks of SZ and the widespread use of anti-apoptotic targets in neurodegeneration, there is a strikingly scarce number of studies investigating anti-apoptotic approaches in SZ. We analyzed the anti-apoptotic approaches conducted in neurodegeneration and the potential applications of such anti-apoptotic therapies as a promising novel therapeutic strategy, especially during early stages.

Ferroptosis Signaling in Pancreatic β-Cells: Novel Insights & Therapeutic Targeting

Metabolic stress impairs pancreatic β-cell survival and function in diabetes. Although the pathophysiology of metabolic stress is complex, aberrant tissue damage and β-cell death are brought on by an imbalance in redox equilibrium due to insufficient levels of endogenous antioxidant expression in β-cells. The vulnerability of β-cells to oxidative damage caused by iron accumulation has been linked to contributory β-cell ferroptotic-like malfunction under diabetogenic settings. Here, we take into account recent findings on how iron metabolism contributes to the deregulation of the redox response in diabetic conditions as well as the ferroptotic-like malfunction in the pancreatic β-cells, which may offer insights for deciphering the pathomechanisms and formulating plans for the treatment or prevention of metabolic stress brought on by β-cell failure.

Regulation mechanism of ferroptosis and its research progress in tumor immunotherapy

Ferroptosis is a novel regulatory cell death, which is characterized by iron dependency and mainly caused by accumulation of intracellular lipid peroxides and reactive oxygen species. Ferroptosis plays an important role in the occurrence and development of a variety of malignant tumors, especially in anti-tumor treatment. As an emerging treatment method, the immunotherapy has been widely applied in the clinical practice, and the role of ferroptosis in tumor immunotherapy has been gradually explored. This study aims to illustrate the features of ferroptosis, and its role in anti-tumor immunotherapy and potential clinical application.

¹H-NMR Metabolic Profiling, Antioxidant Activity, and Docking Study of Common Medicinal Plant-Derived Honey

The purpose of this investigation was to determine ¹H-NMR profiling and antioxidant activity of the most common types of honey, namely, citrus honey (HC1) (Morcott tangerine L. and Jaffa orange L.), marjoram honey (HM1) (Origanum majorana L.), and clover honey (HT1) (Trifolium alexandrinum L.), compared to their secondary metabolites (HC2, HM2, HT2, respectively). By using a ¹H-NMR-based metabolomic technique, PCA, and PLS-DA multivariate analysis, we found that HC2, HM2, HC1, and HM1 were clustered together. However, HT1 and HT2 were quite far from these and each other. This indicated that HC1, HM1, HC2, and HM2 have similar chemical compositions, while HT1 and HT2 were unique in their chemical profiles. Antioxidation potentials were determined colorimetrically for scavenging activities against DPPH, ABTS, ORAC, 5-LOX, and metal chelating activity in all honey extract samples and their secondary metabolites. Our results revealed that HC2 and HM2 possessed more antioxidant activities than HT2 in vitro. HC2 demonstrated the highest antioxidant effect in all assays, followed by HM2 (DPPH assay: IC₅₀ 2.91, 10.7 μg/mL; ABTS assay: 431.2, 210.24 at 50 ug/mL Trolox equivalent; ORAC assay: 259.5, 234.8 at 50 ug/mL Trolox equivalent; 5-LOX screening assay/IC₅₀: 2.293, 6.136 ug/mL; and metal chelating activity at 50 ug/mL: 73.34526%, 63.75881% inhibition). We suggest that the presence of some secondary metabolites in HC and HM, such as hesperetin, linalool, and caffeic acid, increased the antioxidant activity in citrus and marjoram compared to clover honey.

Neuronal ferroptosis after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating form of stroke with high rates of morbidity, mortality, and disability. It induces cell death that is responsible for the secondary brain injury (SBI). The underlying mechanism of SBI after ICH is still unclear, and whether it is related to iron overload is worthy to be discussed. Ferroptosis is an iron-dependent non-apoptotic modes of cell death and plays a particularly important role in the occurrence and progression of ICH. Many ICH-induced regulators and signalling pathways of ferroptosis have been reported as promising targets for treating ICH. In this article, we review the definition, characteristics, and inhibition methods of neuronal ferroptosis caused by iron deposition after ICH, and review the biomarkers for ferroptosis.

Correlation of Ferroptosis and Other Types of Cell Death in Neurodegenerative Diseases

Ferroptosis is defined as an iron-dependent, non-apoptotic cell death pathway, with specific morphological phenotypes and biochemical changes. There is a growing realization that ferroptosis has significant implications for several neurodegenerative diseases. Even though ferroptosis is different from other forms of programmed death such as apoptosis and autophagic death, they involve a number of common protein molecules. This review focuses on current research on ferroptosis and summarizes the cross-talk among ferroptosis, apoptosis, and autophagy that are implicated in neurodegenerative diseases. We hope that this information provides new ideas for understanding the mechanisms and searching for potential therapeutic approaches and prevention of neurodegenerative diseases.

Discovery of 2-vinyl-10H-phenothiazine derivatives as a class of ferroptosis inhibitors with minimal human Ether-a-go-go Related Gene (hERG) Activity for the treatment of DOX-induced cardiomyopathy

Ferroptosis was an iron-dependent, nonapoptotic form of regulated cell death. In our previous study, we discovered a potent ferroptosis inhibitor with phenothiazine scaffold (1), but subsequent investigation showed that this compound had potent hERG binding affinity. Herein, we report the discovery of a series of 2-vinyl-10H-phenothiazine derivatives as new class of ferroptosis inhibitors. Structure-activity relationship (SAR) analyses led to the identification of compound 7j, which exhibited significantly reduced hERG inhibition (IC₅₀ > 30 µM) while maintaining high ferroptosis inhibitory activity (EC₅₀ =0.001 µM on the erastin-induced HT1080 cell ferroptosis model). Further studies confirmed 7j acted as a ROS scavenger and could relieve DOX-induced cardiomyopathy. 7j also displayed favorable pharmacokinetic properties and exhibited no obvious toxicity in vivo and vitro. Overall, this study provides a promising lead compound for drug discovery targeting ferroptosis.

An overview of ferroptosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a public health problem associated with high mortality and high morbidity rates worldwide. Presently, its complex pathophysiology is still unclear, and there is no specific drug to reverse NAFLD. Ferroptosis is an iron-dependent and non-apoptotic form of cell death characterized by the iron-induced accumulation of lipid reactive oxygen species (ROS), which damage nucleic acids, proteins, and lipids; generate intracellular oxidative stress; and ultimately cause cell death. Emerging evidence indicates that ferroptosis is involved in the progression of NAFLD, although the mechanism of action of ferroptosis in NAFLD is still poorly understood. Herein, we summarize the mechanism of action of ferroptosis in certain diseases, especially in the pathogenesis of NAFLD, and discuss the potential therapeutic approaches currently used to treat NAFLD. This review also highlights further directions for the treatment and prevention of NAFLD and related diseases.

Oxidative Stress and Lipid Peroxidation: Prospective Associations Between Ferroptosis and Delayed Wound Healing in Diabetic Ulcers

Diabetic ulcers are one of the major complications of diabetes, and patients usually suffer from amputation and death due to delayed ulcer wound healing. Persistent inflammation and oxidative stress at the wound site are the main manifestations of delayed wound healing in diabetic ulcers. In addition, chronic hyperglycemia in patients can lead to circulatory accumulation of lipid peroxidation products and impaired iron metabolism pathways leading to the presence of multiple free irons in plasma. Ferroptosis, a newly discovered form of cell death, is characterized by intracellular iron overload and accumulation of iron-dependent lipid peroxides. These indicate that ferroptosis is one of the potential mechanisms of delayed wound healing in diabetic ulcers and will hopefully be a novel therapeutic target for delayed wound healing in diabetic patients. This review explored the pathogenesis of diabetic ulcer wound healing, reveals that oxidative stress and lipid peroxidation are common pathological mechanisms of ferroptosis and delayed wound healing in diabetic ulcers. Based on strong evidence, it is speculated that ferroptosis and diabetic ulcers are closely related, and have value of in-depth research. We attempted to clarify prospective associations between ferroptosis and diabetic ulcers in terms of GPX4, iron overload, ferroptosis inhibitors, AGEs, and HO-1, to provide new ideas for exploring the clinical treatment of diabetic ulcers.

Targeting Ferroptosis Pathway to Combat Therapy Resistance and Metastasis of Cancer

Ferroptosis is an iron-dependent regulated form of cell death caused by excessive lipid peroxidation. This form of cell death differed from known forms of cell death in morphological and biochemical features such as apoptosis, necrosis, and autophagy. Cancer cells require higher levels of iron to survive, which makes them highly susceptible to ferroptosis. Therefore, it was found to be closely related to the progression, treatment response, and metastasis of various cancer types. Numerous studies have found that the ferroptosis pathway is closely related to drug resistance and metastasis of cancer. Some cancer cells reduce their susceptibility to ferroptosis by downregulating the ferroptosis pathway, resulting in resistance to anticancer therapy. Induction of ferroptosis restores the sensitivity of drug-resistant cancer cells to standard treatments. Cancer cells that are resistant to conventional therapies or have a high propensity to metastasize might be particularly susceptible to ferroptosis. Some biological processes and cellular components, such as epithelial–mesenchymal transition (EMT) and noncoding RNAs, can influence cancer metastasis by regulating ferroptosis. Therefore, targeting ferroptosis may help suppress cancer metastasis. Those progresses revealed the importance of ferroptosis in cancer, In order to provide the detailed molecular mechanisms of ferroptosis in regulating therapy resistance and metastasis and strategies to overcome these barriers are not fully understood, we described the key molecular mechanisms of ferroptosis and its interaction with signaling pathways related to therapy resistance and metastasis. Furthermore, we summarized strategies for reversing resistance to targeted therapy, chemotherapy, radiotherapy, and immunotherapy and inhibiting cancer metastasis by modulating ferroptosis. Understanding the comprehensive regulatory mechanisms and signaling pathways of ferroptosis in cancer can provide new insights to enhance the efficacy of anticancer drugs, overcome drug resistance, and inhibit cancer metastasis.

Induction of Ferroptosis by Ophiopogonin-B Through Regulating the Gene Signature AURKA in NSCLC

Ferroptosis is a new type of iron-dependent programmed cell death. In recent years, its role in the diagnosis and treatment of multiple tumors, including non-small cell lung cancer (NSCLC), has been continuously observed. The relationship between the ferroptosis-related genes and the prognosis of patients with NSCLC needs to be clarified. In this study, The Cancer Genome Atlas (TCGA) and the Gene Expression Synthesis database (Gene Expression Omnibus, GEO) were used to build a model of ferroptosis-related differentially expressed genes (DEGs). A total of 101 ferroptosis-related DEGs were screened using R language, and a 12-gene signature was finally established through univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO)-penalized Cox regression analysis. According to the risk scores, the patients were divided into a high-risk or a low-risk group, with patients in the low-risk group showing better prognosis. AURKA, one of the genes in the 12-gene signature, was found to be highly expressed in tumors. In addition, further study verified AURKA to be a negative regulator of ferroptosis in NSCLC cells. Ophiopogonin B (OP-B) had been reported to induce apoptosis, mitotic catastrophe, and autophagy in NSCLC cells. Herein, proteomic sequencing analysis and OP-B administration revealed the upregulation of AURKA and the downregulation of PHKG2 and SLC7A5 in the 12-gene signature, indicating that OP-B induced ferroptosis in NSCLC. Determination of the concentrations of malondialdehyde (MDA), glutathione (GSH), and intracellular iron and the mitochondrial membrane potential (MMP) confirmed the induction of ferroptosis by OP-B in vitro. Furthermore, transmission electron microscopy (TEM) examination of lung cancer xenotransplantation in nude mice confirmed that OP-B induced ferroptosis in vivo. Further study of the molecular mechanism showed that the ferroptosis effect caused by OP-B can be partially reversed by the overexpression of AURKA. Overall, our study established a new ferroptosis-related risk prediction model for the prognosis of patients with NSCLC, revealed the enrichment pathways of ferroptosis in NSCLC, and discovered the negative regulation of AURKA in ferroptosis. On this basis, we demonstrated that OP-B can induce ferroptosis in NSCLC and clarified the specific molecular mechanism of OP-B inducing ferroptosis by regulating the expression of AURKA.

Propofol Protects Against Erastin-Induced Ferroptosis in HT-22 Cells

Propofol is a short-acting intravenous anesthetic that is widely used in clinical treatment. Previous articles have indicated that propofol is a therapeutic target for anti-apoptosis, anti-inflammation, anti-lipid peroxidation, and anti-reactive oxygen species (ROS). Moreover, cell ferroptosis is strongly correlated with cellular ROS, inflammatory responses, and lipid peroxidation. However, the mechanisms by which propofol attenuates neuronal injury by reducing ferroptosis remain unknown. Hence, we hypothesized that propofol could protect neurons by reducing ferroptosis. To test this hypothesis, HT-22 cells were treated with a specific ferroptosis activator (erastin) in the presence of propofol (50 μM). We found that propofol reduced erastin-induced high Fe²⁺ concentrations, lipid peroxides, and excess ROS. Western blotting results also suggested that propofol could rescue erastin-induced low expression of GXP4 and system Xc^-. Further experiments indicated that propofol attenuated p-ALOX5 expression at Ser663 independent of ERK. In addition, we built two transient transfection cell lines, ALOX5 OE and Ser663Ala-ALOX5 OE, to confirm the target of propofol. We found that the Ser663 point is the critical role of propofol in rescuing erastin-induced cell injury/lipid peroxidation. In conclusion, propofol may help attenuate ferroptosis, which may provide a new therapeutic method to treat neuronal injury or the brain inflammatory response.

Edaravone Modulates Neuronal GPX4/ACSL4/5-LOX to Promote Recovery After Spinal Cord Injury

The FDA-approved drug edaravone has a neuroprotective effect on spinal cord injury (SCI) and many other central nervous system diseases. However, its molecular mechanism remains unclear. Since edaravone is a lipid peroxidation scavenger, we hypothesize that edaravone exerts its neuroprotective effect by inhibiting ferroptosis in SCI. Edaravone treatment after SCI upregulates glutathione peroxidase 4 (GPX4) and system Xc-light chain (xCT), which are anti-ferroptosis proteins. It downregulates pro-ferroptosis proteins Acyl-CoA synthetase long-chain family member 4 (ACSL4) and 5-lipoxygenase (5-LOX). The most significant changes in edaravone treatment occur in the acute phase, two days post injury. Edaravone modulates neuronal GPX4/ACSL4/5-LOX in the spinal segment below the lesion, which is critical for maintaining locomotion. Moreover, the GPX4/ACSL4/5-LOX in motor neuron is also modulated by edaravone in the spinal cord. Therefore, secondary injury below the lesion site is reversed by edaravone via ferroptosis inhibition. The cytokine array revealed that edaravone upregulated some anti-inflammatory cytokines such as IL-10, IL-13, and adiponectin. Edaravone reduced microgliosis and astrogliosis, indicating reduced neuroinflammation. Edaravone has a long-term effect on neuronal survival, spinal cord tissue sparing, and motor function recovery. In summary, we revealed a novel mechanism of edaravone in inhibiting neuronal ferroptosis in SCI. This mechanism may be generalizable to other neurological diseases.

Therapeutic Implications of Ferroptosis in Renal Fibrosis

Renal fibrosis is a common feature of chronic kidney disease (CKD), and can lead to the destruction of normal renal structure and loss of kidney function. Little progress has been made in reversing fibrosis in recent years. Ferroptosis is more immunogenic than apoptosis due to the release and activation of damage-related molecular patterns (DAMPs) signals. In this paper, the relationship between renal fibrosis and ferroptosis was reviewed from the perspective of iron metabolism and lipid peroxidation, and some pharmaceuticals or chemicals associated with both ferroptosis and renal fibrosis were summarized. Other programmed cell death and ferroptosis in renal fibrosis were also firstly reviewed for comparison and further investigation.

Critical involvement of lysyl oxidase in seizure-induced neuronal damage through ERK-Alox5-dependent ferroptosis and its therapeutic implications

Recent insights collectively suggest the important roles of lysyl oxidase (LysOX) in the pathological processes of several acute and chronic neurological diseases, but the molecular regulatory mechanisms remain elusive. Herein, we explore the regulatory role of LysOX in the seizure-induced ferroptotic cell death of neurons. Mechanistically, LysOX promotes ferroptosis-associated lipid peroxidation in neurons via activating extracellular regulated protein kinase (ERK)-dependent 5-lipoxygenase (Alox5) signaling. In addition, overexpression of LysOX via adeno-associated viral vector (AAV)-based gene transfer enhances ferroptosis sensitivity and aggravates seizure-induced hippocampal damage. Our studies show that pharmacological inhibition of LysOX with β-aminopropionitrile (BAPN) significantly blocks seizure-induced ferroptosis and thereby alleviates neuronal damage, while the BAPN-associated cardiotoxicity and neurotoxicity could further be reduced through encapsulation with bioresponsive amorphous calcium carbonate-based nanocarriers. These findings unveil a previously unrecognized LysOX-ERK-Alox5 pathway for ferroptosis regulation during seizure-induced neuronal damage. Suppressing this pathway may yield therapeutic implications for restoring seizure-induced neuronal injury.

Ferroptosis in Cardiovascular Diseases: Current Status, Challenges, and Future Perspectives

Cardiovascular diseases (CVDs) are still a major cause of global mortality and disability, seriously affecting people’s lives. Due to the severity and complexity of these diseases, it is important to find new regulatory mechanisms to treat CVDs. Ferroptosis is a new kind of regulatory cell death currently being investigated. Increasing evidence showed that ferroptosis plays an important role in CVDs, such as in ischemia/reperfusion injury, heart failure, cardiomyopathy, and atherosclerosis. Protecting against CVDs by targeting ferroptosis is a promising approach; therefore, in this review, we summarized the latest regulatory mechanism of ferroptosis and the current studies related to each CVD, followed by critical perspectives on the ferroptotic treatment of CVDs and the future direction of this intriguing biology.

5-Lipoxygenase Inhibition Protects Retinal Pigment Epithelium from Sodium Iodate-Induced Ferroptosis and Prevents Retinal Degeneration

Excessive reactive oxygen species (ROS) contribute to damage of retinal cells and the development of retinal diseases including age-related macular degeneration (AMD). ROS result in increased metabolites of lipoxygenases (LOXs), which react with ROS to induce lipid peroxidation and may lead to ferroptosis. In this study, the effect of 5-LOX inhibition on alleviating ROS-induced cell death was evaluated using sodium iodate (NaIO₃) in the retinal pigment epithelium (RPE) cell line ARPE-19 and a mouse model investigating oxidative stress in AMD. We demonstrated that NaIO₃ induced cell death in the RPE cells through mechanisms including ferroptosis. Inhibition of 5-LOX with specific inhibitor, Zileuton, or siRNA knockdown of ALXO5 mitigated NaIO₃-induced lipid peroxidation, mitochondrial damage, DNA impairment, and cell death in ARPE-19 cells. Additionally, in the mouse model, pretreatment with Zileuton reduced the NaIO₃-induced lipid peroxidation of RPE cells, cell death in the photoreceptor layer of the retina, inflammatory responses, and degeneration of both the neuroretina and RPE monolayer cells. Our results suggest that 5-LOX plays a crucial role in ROS-induced cell death in the RPE and that regulating 5-LOX activity could be a useful approach to control ROS and ferroptosis-induced damage, which promote degeneration in retinal diseases.

The multifaceted role of ferroptosis in liver disease

Ferroptosis is an iron-dependent form of non-apoptotic cell death characterized by excessive lipid peroxidation and associated with a plethora of pathological conditions in the liver. Emerging evidence supports the notion that dysregulated metabolic pathways and impaired iron homeostasis play a role in the progression of liver disease via ferroptosis. Although the molecular mechanisms by which ferroptosis causes disease are poorly understood, several ferroptosis-associated genes and pathways have been implicated in liver disease. Here, we review the physiological role of the liver in processing nutrients, our current understanding of iron metabolism, the characteristics of ferroptosis, and the mechanisms that regulate ferroptosis. In addition, we summarize the role of ferroptosis in the pathogenesis of liver disease, including liver injury, non-alcoholic steatohepatitis, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Finally, we discuss the therapeutic potential of targeting ferroptosis for managing liver disease.

Emerging Mechanisms and Disease Implications of Ferroptosis: Potential Applications of Natural Products

Ferroptosis, a newly discovered form of regulatory cell death (RCD), has been demonstrated to be distinct from other types of RCD, such as apoptosis, necroptosis, and autophagy. Ferroptosis is characterized by iron-dependent lipid peroxidation and oxidative perturbation, and is inhibited by iron chelators and lipophilic antioxidants. This process is regulated by specific pathways and is implicated in diverse biological contexts, mainly including iron homeostasis, lipid metabolism, and glutathione metabolism. A large body of evidence suggests that ferroptosis is interrelated with various physiological and pathological processes, including tumor progression (neuro)degenerative diseases, and hepatic and renal failure. There is an urgent need for the discovery of novel effective ferroptosis-modulating compounds, even though some experimental reagents and approved clinical drugs have been well documented to have anti- or pro-ferroptotic properties. This review outlines recent advances in molecular mechanisms of the ferroptotic death process and discusses its multiple roles in diverse pathophysiological contexts. Furthermore, we summarize chemical compounds and natural products, that act as inducers or inhibitors of ferroptosis in the prevention and treatment of various diseases. Herein, it is particularly highlighted that natural products show promising prospects in ferroptosis-associated (adjuvant) therapy with unique advantages of having multiple components, multiple biotargets and slight side effects.

Rethinking IRPs/IRE system in neurodegenerative disorders: Looking beyond iron metabolism

Iron regulatory proteins (IRPs) and iron regulatory element (IRE) systems are well known in the progression of neurodegenerative disorders by regulating iron related proteins. IRPs are also regulated by iron homeostasis. However, an increasing number of studies have suggested a close relationship between the IRPs/IRE system and non-iron-related neurodegenerative disorders. In this paper, we reviewed that the IRPs/IRE system is not only controlled by iron ions, but also regulated by such factors as post-translational modification, oxygen, nitric oxide (NO), heme, interleukin-1 (IL-1), and metal ions. In addition, by regulating the transcription of non-iron related proteins, the IRPs/IRE system functioned in oxidative metabolism, cell cycle regulation, abnormal proteins aggregation, and neuroinflammation. Finally, by emphasizing the multiple regulations of IRPs/IRE system and its potential relationship with non-iron metabolic neurodegenerative disorders, we provided new strategies for disease treatment targeting IRPs/IRE system.

Research progress on the mechanism of ferroptosis and its clinical application

Ferroptosis is a mode of cell death dependent on iron ions, which is mainly induced by the decrease of the biological activity of glutathione peroxidase or the accumulation of lipid peroxidation and reactive oxygen species (ROS). It is significantly different from autophagy and other forms of cell death in terms of cell morphology and biochemistry. The exact mechanisms of ferroptosis are not clear. More and more studies have shown that various tumor diseases and nervous system diseases are closely related to ferroptosis. The occurrence and development of related diseases can be tolerated by stimulating or inhibiting the occurrence of ferroptosis. Therefore, ferroptosis has occupied a very important position in recent years. This article reviews the discovery process, characteristics, mechanisms, inducers, inhibitors of ferroptosis and its related clinical applications to lay a foundation for follow-up researchers to study ferroptosis and provide some reference value.

Iron overload and mitochondrial dysfunction orchestrate pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic, progressive heterogeneous disease of lung tissues with poor lung function caused by scar tissue. Due to our limited understanding of its mechanism, there is currently no treatment strategy that can prevent the development of PF. In recent years, iron accumulation and mitochondrial damage have been reported to participate in PF, and drugs that reduce iron content and improve mitochondrial function have shown significant efficacy in animal experimental models. Excessive iron leads to mitochondrial impairment, which may be the key cause that results in the dysfunction of various kinds of pulmonary cells and further promotes PF. As an emerging research hotspot, there are few targeted effective therapeutic strategies at present due to limited mechanistic understanding. In this review, the roles of iron homeostasis imbalance and mitochondrial damage in PF are summarized and discussed, highlighting a promising direction for finding truly effective therapeutics for PF.

A Novel Insight Into the Fate of Cardiomyocytes in Ischemia-Reperfusion Injury: From Iron Metabolism to Ferroptosis

Ischemia-reperfusion injury (IRI), critically involved in the pathology of reperfusion therapy for myocardial infarction, is closely related to oxidative stress the inflammatory response, and disturbances in energy metabolism. Emerging evidence shows that metabolic imbalances of iron participate in the pathophysiological process of cardiomyocyte IRI [also termed as myocardial ischemia-reperfusion injury (MIRI)]. Iron is an essential mineral required for vital physiological functions, including cellular respiration, lipid and oxygen metabolism, and protein synthesis. Nevertheless, cardiomyocyte homeostasis and viability are inclined to be jeopardized by iron-induced toxicity under pathological conditions, which is defined as ferroptosis. Upon the occurrence of IRI, excessive iron is transported into cells that drive cardiomyocytes more vulnerable to ferroptosis by the accumulation of reactive oxygen species (ROS) through Fenton reaction and Haber–Weiss reaction. The increased ROS production in ferroptosis correspondingly leads cardiomyocytes to become more sensitive to oxidative stress under the exposure of excess iron. Therefore, ferroptosis might play an important role in the pathogenic progression of MIRI, and precisely targeting ferroptosis mechanisms may be a promising therapeutic option to revert myocardial remodeling. Notably, targeting inhibitors are expected to prevent MIRI deterioration by suppressing cardiomyocyte ferroptosis. Here, we review the pathophysiological alterations from iron homeostasis to ferroptosis together with potential pathways regarding ferroptosis secondary to cardiovascular IRI. We also provide a comprehensive analysis of ferroptosis inhibitors and initiators, as well as regulatory genes involved in the setting of MIRI.

The Regulatory Effects and the Signaling Pathways of Natural Bioactive Compounds on Ferroptosis

Natural bioactive compounds abundantly presented in foods and medicinal plants have recently received a remarkable attention because of their various biological activities and minimal toxicity. In recent years, many natural compounds appear to offer significant effects in the regulation of ferroptosis. Ferroptosis is the forefront of international scientific research which has been exponential growth since the term was coined. This type of regulated cell death is driven by iron-dependent phospholipid peroxidation. Recent studies have shown that numerous organ injuries and pathophysiological processes of many diseases are driven by ferroptosis, such as cancer, arteriosclerosis, neurodegenerative disease, diabetes, ischemia-reperfusion injury and acute renal failure. It is reported that the initiation and inhibition of ferroptosis plays a pivotal role in lipid peroxidation, organ damage, neurodegeneration and cancer growth and progression. Recently, many natural phytochemicals extracted from edible plants have been demonstrated to be novel ferroptosis regulators and have the potential to treat ferroptosis-related diseases. This review provides an updated overview on the role of natural bioactive compounds and the potential signaling pathways in the regulation of ferroptosis.

Different functions of vitamin E homologues in the various types of cell death induced by oxysterols

24(S)-Hydroxycholesterol (24S-OHC) and 25-hydroxycholesterol (25-OHC) are produced by cholesterol 24-hydroxylase and cholesterol 25-hydroxylase, respectively. The purpose of the present study was to determine the type of cell death induced by these oxysterols in neuronal cells, hepatic cells, and keratinocytes, and to elucidate the inhibitory effect of vitamin E homologues on various types of cell death. In human neuronal cells (SH-SY5Y cells), 24S-OHC and 25-OHC caused a cell death that was independent of caspase activation. We reported previously that the esterification of 24S-OHC by acyl-CoA:cholesterol acyltransferase 1 (ACAT1) and the resulting formation of a lipid droplet (LD)-like structure are responsible for the 24S-OHC-induced neuronal cell death. Here, we found that 25-OHC also induced ACAT1-mediated 25-OHC esterification and LD formation in neuronal cells. 25-OHC-induced cell death was inhibited by α-tocopherol (α-Toc) but not by α-tocotrienol (α-Toc3), as observed for 24S-OHC-induced cell death in SH-SY5Y cells. In human hepatic cells (HepG2 cells), these oxysterols caused a cell death that was caspase- and oxysterol-esterification-independent. This cell death was suppressed by both α-Toc and α-Toc3, suggesting the involvement of free-radical-mediated lipid peroxidation in the cell death induced by these oxysterols in hepatic cells. In human keratinocytes (HaCaT cells), these oxysterols caused a caspase-dependent but oxysterol-esterification-independent cell death that was inhibited by α-Toc but not by α-Toc3. These results suggest that α-Toc and α-Toc3 act as radical-scavenging antioxidants against oxysterol-induced cell death in the same way in hepatic cells, whereas their behavior is different in inhibition of cell death in neuronal cells and keratinocytes. Collectively, these results demonstrated that 24S-OHC and 25-OHC induced the same type of cell death in each of the cell types examined, and that α-Toc and α-Toc3 exerted different effects, depending on the type of cell death.

Comprehensive Analysis of the Tumor Microenvironment and Ferroptosis-Related Genes Predict Prognosis with Ovarian Cancer

The early diagnosis of ovarian cancer (OC) is critical to improve the prognosis and prevent recurrence of patients. Nevertheless, there is still a lack of factors which can accurately predict it. In this study, we focused on the interaction of immune infiltration and ferroptosis and selected the ESTIMATE algorithm and 15 ferroptosis-related genes (FRGs) to construct a novel E-FRG scoring model for predicting overall survival of OC patients. The gene expression and corresponding clinical characteristics were obtained from the TCGA dataset (n = 375), GSE18520 (n = 53), and GSE32062 (n = 260). A total of 15 FRGs derived from FerrDb with the immune score and stromal score were identified in the prognostic model by using least absolute shrinkage and selection operator (LASSO)-penalized COX regression analysis. The Kaplan-Meier survival analysis and time-dependent ROC curves performed a powerful prognostic ability of the E-FRG model via multi-validation. Gene Set Enrichment Analysis and Gene Set Variation Analysis elucidate multiple potential pathways between the high and low E-FRG score group. Finally, the proteins of different genes in the model were verified in drug-resistant and non-drug-resistant tumor tissues. The results of this research provide new prospects in the role of immune infiltration and ferroptosis as a helpful tool to predict the outcome of OC patients.

Interferon-γ induces retinal pigment epithelial cell Ferroptosis by a JAK1-2/STAT1/SLC7A11 signaling pathway in Age-related Macular Degeneration

Retinal pigment epithelium (RPE) cell damage is implicated in the pathogenesis of age-related macular degeneration (AMD). An increase of interferon-γ (IFN-γ) levels was observed in patients with AMD, but whether inflammatory factors are causally related to AMD progression is unclear. Here, we demonstrate a direct causal relationship between IFN-γ and RPE cell death. IFN-γ induced human retinal pigment epithelial cell (ARPE-19) death accompanied by increases in Fe²⁺ , reactive oxygen species, lipid peroxidation, and glutathione (GSH) depletion, which are main characteristics of ferroptosis. Mechanistically, IFN-γ upregulates the level of intracellular Fe²⁺ through inhibiting Fe²⁺ efflux protein SLC40A1 and induces GSH depletion by blocking cystine/glutamate antiporter, System xc-. At the same time, treatment with IFN-γ decreases the level of glutathione peroxidase 4 (GPx4), rendering the cells more sensitive to ferroptosis. JAK1/2 and STAT1 inhibitors could reverse the reduction of SLC7A11, GPx4 and GSH expression induced by IFN-γ, indicating IFN-γ induces ARPE-19 cell ferroptosis via activation of the JAK1-2/STAT1/SLC7A11 signaling pathway. The above results were largely confirmed in IFN-γ-treated mice in vivo. Finally, we used sodium iodate (NaIO₃ )-induced retinal degeneration to further explore the role of ferroptosis in AMD in vivo. Consistent with the role of IFN-γ, treatment with NaIO₃ decreased SLC7A11, GPx4 and SLC40A1 expressions. NaIO₃ -induced RPE damage was accompanied by increased iron, lipid peroxidation products (4-hydroxynonenal, malondialdehyde), and GSH depletion, and ferroptosis inhibitors could reverse the above phenomenon. Taken together, our findings suggest that inhibiting ferroptosis or reducing IFN-γ may serve as a promising target for AMD.

Ferroptosis: Opportunities and Challenges in Myocardial Ischemia-Reperfusion Injury

Ferroptosis is a newly discovered form of regulated cell death dependent on iron and reactive oxygen species (ROS). It directly or indirectly affects the activity of glutathione peroxidases (GPXs) under the induction of small molecules, causing membrane lipid peroxidation due to redox imbalances and excessive ROS accumulation, damaging the integrity of cell membranes. Ferroptosis is mainly characterized by mitochondrial shrinkage, increased density of bilayer membranes, and the accumulation of lipid peroxidation. Myocardial ischemia-reperfusion injury (MIRI) is an unavoidable risk event for acute myocardial infarction. Ferroptosis is closely associated with MIRI, and this relationship is discussed in detail here. This review systematically summarizes the process of ferroptosis and the latest research progress on the role of ferroptosis in MIRI to provide new ideas for the prevention and treatment of MIRI.

Toward improved human health: Nrf2 plays a critical role in regulating ferroptosis

Ferroptosis is a recently defined type of regulated cell death caused by an excess iron-dependent accumulation of lipid peroxides and is morphologically and biochemically distinct from other types of cell death. Notably, Nrf2 is identified to exquisitely modulate ferroptosis due to its ability to target a host of ferroptosis cascade genes, which places Nrf2 in the pivotal position of ferroptosis. This paper reviews the regulation effect of Nrf2 on ferroptosis, different activation mechanisms of Nrf2 as well as the relevance of the Nrf2-ferroptosis axis in diseases, and finally summarizes foods with beneficial effects in ferroptosis via the Nrf2 pathway and aims to serve as a reference for follow-up studies of food functions related to Nrf2, ferroptosis, and human health.

Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression

Breast cancer has become a serious threat to women's health. Cancer progression is mainly derived from resistance to apoptosis induced by procedures or therapies. Therefore, new drugs or models that can overcome apoptosis resistance should be identified. Ferroptosis is a recently identified mode of cell death characterized by excess reactive oxygen species-induced lipid peroxidation. Since ferroptosis is distinct from apoptosis, necrosis and autophagy, its induction successfully eliminates cancer cells that are resistant to other modes of cell death. Therefore, ferroptosis may become a new direction around which to design breast cancer treatment. Unfortunately, the complete appearance of ferroptosis in breast cancer has not yet been fully elucidated. Furthermore, whether ferroptosis inducers can be used in combination with traditional anti- breast cancer drugs is still unknown. Moreover, a summary of ferroptosis in breast cancer progression and therapy is currently not available. In this review, we discuss the roles of ferroptosis-associated modulators glutathione, glutathione peroxidase 4, iron, nuclear factor erythroid-2 related factor-2, superoxide dismutases, lipoxygenase and coenzyme Q in breast cancer. Furthermore, we provide evidence that traditional drugs against breast cancer induce ferroptosis, and that ferroptosis inducers eliminate breast cancer cells. Finally, we put forward prospect of using ferroptosis inducers in breast cancer therapy, and predict possible obstacles and corresponding solutions. This review will deepen our understanding of the relationship between ferroptosis and breast cancer, and provide new insights into breast cancer-related therapeutic strategies.

Erastin induces ferroptosis via ferroportin-mediated iron accumulation in endometriosis

STUDY QUESTION

Could erastin activate ferroptosis to regress endometriotic lesions?

SUMMARY ANSWER

Erastin could induce ferroptosis to regress endometriotic lesions in endometriosis.

WHAT IS KNOWN ALREADY

Ectopic endometrial stromal cells (EESCs) are in an iron overloading microenvironment and tend to be more sensitive to oxidative damage. The feature of erastin-induced ferroptosis is iron-dependent accumulation of lethal lipid reactive oxygen species (ROS).

STUDY DESIGN, SIZE, DURATION

Eleven patients without endometriosis and 21 patients with endometriosis were recruited in this study. Primary normal and ectopic endometrial stromal cells were isolated, cultured and subjected to various treatments. The in vivo study involved 10 C57BL/6 female mice to establish the model of endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The markers of ferroptosis were assessed by cell viability, lipid peroxidation level and morphological changes. The cell viability was measured by colorimetric method, lipid peroxidation levels were measured by flow cytometry, and morphological changes were observed by transmission electron microscopy. Immunohistochemistry and western blot were used to detect ferroportin (FPN) expression. Prussian blue staining and immunofluorescent microscopy of catalytic ferrous iron were semi-quantified the levels of iron. Adenovirus-mediated overexpression and siRNA-mediated knockdown were used to investigate the role of FPN on erastin-induced ferroptosis in EESCs.

MAIN RESULTS AND THE ROLE OF CHANCE

EESCs were more susceptible to erastin treatment, compared to normal endometrial stromal cells (NESCs) (P<0.05). Treatment of cultured EESCs with erastin dramatically increased the total ROS level (P<0.05, versus control), lipid ROS level (P<0.05, versus NESCs) and intracellular iron level (P<0.05, versus NESCs). The cytotoxicity of erastin could be attenuated by iron chelator, deferoxamine (DFO), and ferroptosis inhibitors, ferrostatin-1 and liproxstatin-1, (P<0.05, versus erastin) in EESCs. In EESCs with erastin treatment, shorter and condensed mitochondria were observed by electron microscopy. These findings together suggest that erastin is capable to induce EESC death by ferroptosis. However, the influence of erastin on NESCs was slight. The process of erastin-induced ferroptosis in EESCs accompanied iron accumulation and decreased FPN expression. The overexpression of FPN ablated erastin-induced ferroptosis in EESCs. In addition, knockdown of FPN accelerated erastin-induced ferroptosis in EESCs. In a mouse model of endometriosis, we found ectopic lesions were regressed after erastin administration.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This study was mainly conducted in primary human endometrial stromal cells. Therefore, the function of FPN in vivo need to be further investigated.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings reveal that erastin may serve as a potential therapeutic treatment for endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors. The authors declare no conflict of interest.

Lipid Metabolism in Ferroptosis

Lipid metabolism is a complex biochemical process that participates in the regulation of cell survival and death. Ferroptosis is a form of iron-dependent regulated cell death driven by abnormal lipid metabolism, leading to lipid peroxidation and subsequent plasma membrane rupture. A variety of antioxidant systems and membrane repair pathways can diminish oxidative damage, enabling survival and growth in response to ferroptotic signals. Such impairment of ferroptosis machinery is implicated in various pathological conditions and diseases, especially cancer and tissue damage. It is discussed here how lipid metabolism pathways, including lipid synthesis, degradation, storage, transformation, and utilization, modulate ferroptosis sensitivity or tolerance in different models, especially cancer.

Ferroptosis: mechanisms and links with diseases

Ferroptosis is an iron-dependent cell death, which is different from apoptosis, necrosis, autophagy, and other forms of cell death. The process of ferroptotic cell death is defined by the accumulation of lethal lipid species derived from the peroxidation of lipids, which can be prevented by iron chelators (e.g., deferiprone, deferoxamine) and small lipophilic antioxidants (e.g., ferrostatin, liproxstatin). This review summarizes current knowledge about the regulatory mechanism of ferroptosis and its association with several pathways, including iron, lipid, and cysteine metabolism. We have further discussed the contribution of ferroptosis to the pathogenesis of several diseases such as cancer, ischemia/reperfusion, and various neurodegenerative diseases (e.g., Alzheimer's disease and Parkinson's disease), and evaluated the therapeutic applications of ferroptosis inhibitors in clinics.

Mechanism of Ferroptosis: A Potential Target for Cardiovascular Diseases Treatment

Ferroptosis is a form of programmed cell death caused by production of reactive oxygen species and disequilibrium of iron homeostasis. Many chemical compounds and clinical drugs induce ferroptosis in normal and cancer cells, while peroxidation inhibitors, iron chelators, and antioxidants can block ferroptosis. Glutathione peroxidase 4, ferroptosis suppressor protein 1, nuclear factor erythroid 2-related factor 2, and system Xc^- are the negative regulators of ferroptosis, whereas nicotinamide adenine dinucleotide phosphate oxidase, p53, mitochondria voltage-dependent anion channel, and cysteinyl-tRNA synthetase function as positive regulators. Ferroptosis plays important roles in pathogen infection and tumor immunology. Recent studies suggest that ferroptosis plays a vital role in the pathogenesis of cardiovascular diseases (CVDs), which seriously threaten human health. Potential therapies designed around ferroptosis may alter the pathological progression of CVDs. Therefore, we redacted an overview of the discovery of ferroptosis, its regulatory mechanisms, and its potential impact on CVDs treatment.

Structure-activity relationship studies of phenothiazine derivatives as a new class of ferroptosis inhibitors together with the therapeutic effect in an ischemic stroke model

Ferroptosis is a new type of programmed cell death discovered recently and has been demonstrated to be involved in a number of human diseases such as ischemic stroke. Ferroptosis inhibitors are expected to have potential to treat these diseases. Herein, we report the identification of promethazine derivatives as a new type of ferroptosis inhibitors. Structure-activity relationship (SAR) analyses led to the discovery of the most potent compound 2-(1-(4-(4-methylpiperazin-1-yl)phenyl)ethyl)-10H-phenothiazine (51), which showed an EC50 (half maximal effective concentration) value of 0.0005 μM in the erastin-induced HT1080 cell ferroptosis model. In the MCAO (middle cerebral artery occlusion) ischemic stroke model, 51 presented an excellent therapeutic effect. This compound also displayed favorable pharmacokinetic properties, in particular, a good ability to permeate the blood-brain barrier. Overall, 51 could be a promising lead compound for the treatment of ferroptosis related diseases and deserves further investigations.

Small Molecule Regulators of Ferroptosis

Ferroptosis is a dedicated mode of cell death involving iron, reactive oxygen species and lipid peroxidation. Involved in processes such as glutathione metabolism, lysosomal iron retention or interference with lipid metabolism, leading either to activation or inhibition of ferroptosis. Given the implications of ferroptosis in diseases such as cancer, aging, Alzheimer and infectious diseases, new molecular mechanisms underlying ferroptosis and small molecules regulators that target those mechanisms have prompted a great deal of interest. Here, we discuss the current scenario of small molecules modulating ferroptosis and critically assess what is known about their mechanisms of action.

Development and Validation of a Combined Ferroptosis and Immune Prognostic Classifier for Hepatocellular Carcinoma

Background

Immunotherapy and sorafenib exert anti-tumor effects via ferroptosis, but reliable biomarkers for the individual treatment and prognosis prediction of hepatocellular carcinoma (HCC) based on the ferroptosis and immune status remain lacking.

Methods

Ferroptosis-related genes (FRGs) were identified by downloading data from FerrDb and by searching and reading original articles from PubMed. Immune-related genes (IRGs) were downloaded from ImmPort. Prognostic FRGs and IRGs in the GSE14520 (n = 220) and The Cancer Genome Atlas (TCGA, n = 365) datasets were identified. Least absolute shrinkage and selection operator (LASSO) Cox regression and multivariate Cox regression were used for model construction. Ferroptosis expression profiles, the infiltration of immune cells, and the somatic mutation status were analyzed and compared.

Results

Twenty-seven prognostic ferroptosis- and immune-related signatures were included to construct a comprehensive index of ferroptosis and immune status (CIFI). A subgroup of patients was identified as having a high CIFI value, which was associated with a worse prognosis. This subgroup of patients had significantly up-regulated expressions of many suppressors of ferroptosis and higher fractions of immunosuppressive cells, such as cancer-associated fibroblasts (CAFs) and myeloid-derived suppressor cells (MDSCs). Notably, somatic mutation analysis indicated that high-CIFI patients had higher levels of tumor heterogeneity and higher mutation frequencies of genes like TP53.

Conclusion

In this work, a novel prognostic classifier was developed based on ferroptosis- and IRGs in HCC, and this classifier could be used for prognostic prediction and the selection of patients for immunotherapies and targeted therapies.

Using the Oxytosis/Ferroptosis Pathway to Understand and Treat Age-Associated Neurodegenerative Diseases

Oxytosis was first described over 30 years ago in nerve cells as a non-excitotoxic pathway for glutamate-induced cell death. The key steps of oxytosis, including glutathione depletion, lipoxygenase activation, reactive oxygen species accumulation, and calcium influx, were identified using a combination of chemical and genetic tools. A pathway with the same characteristics as oxytosis was identified in transformed fibroblasts in 2012 and named ferroptosis. Importantly, the pathophysiological changes seen in oxytosis and ferroptosis are also observed in multiple neurodegenerative diseases as well as in the aging brain. This led to the hypothesis that this pathway could be used as a screening tool to identify novel drug candidates for the treatment of multiple age-associated neurological disorders, including Alzheimer's disease (AD). Using this approach, we have identified several AD drug candidates, one of which is now in clinical trials, as well as new target pathways for AD.

Neuroprotective Effects of the Anti-cancer Drug Lapatinib Against Epileptic Seizures via Suppressing Glutathione Peroxidase 4-Dependent Ferroptosis

Epilepsy is a complex neurological disorder characterized by recurrent and unprovoked seizures. Neuronal death process is implicated in the development of repetitive epileptic seizures. Therefore, cell death can be harnessed for ceasing seizures and epileptogenesis. Oxidative stress is regarded as a contributing factor of neuronal death activation and there is compelling evidence supporting antioxidants hold promise in abrogating seizure-related cell modality. Lapatinib, a well-known anti-cancer drug, has been traditionally reported to exert anti-tumor effect via modulating oxidative stress and a recent work illustrates the improvement of encephalomyelitis in rodent models after lapatinib treatment. However, whether lapatinib is beneficial for inhibiting neuronal death and epileptic seizure remains unknown. Here, we found that lapatinib remarkably prevented kainic acid (KA)-epileptic seizures in mice and ferroptosis, a newly defined cell death which is associated with oxidative stress, was involved in the neuroprotection of lapatinib. In the ferroptotic cell death model, lapatinib exerted neuroprotection via restoring glutathione peroxidase 4 (GPX4). Treatment with GPX4 inhibitor ras-selective lethal small molecule 3 (RSL3) abrogated its anti-ferroptotic potential. In a mouse model of KA-triggered seizure, it was also validated that lapatinib blocked GPX4-dependent ferroptosis. It is concluded that lapatinib has neuroprotective potential against epileptic seizures via suppressing GPX4-mediated ferroptosis.

Iron Metabolism and Ferroptosis in Epilepsy

Epilepsy is a disease characterized by recurrent, episodic, and transient central nervous system (CNS) dysfunction resulting from an excessive synchronous discharge of brain neurons. It is characterized by diverse etiology, complex pathogenesis, and difficult treatment. In addition, most epileptic patients exhibit social cognitive impairment and psychological impairment. Iron is an essential trace element for human growth and development and is also involved in a variety of redox reactions in organisms. However, abnormal iron metabolism is associated with several neurological disorders, including hemorrhagic post-stroke epilepsy and post-traumatic epilepsy (PTE). Moreover, ferroptosis is also considered a new form of regulation of cell death, which is attributed to severe lipid peroxidation caused by the production of reactive oxygen species (ROS) and iron overload found in various neurological diseases, including epilepsy. Therefore, this review summarizes the study on iron metabolism and ferroptosis in epilepsy, in order to elucidate the correlation between iron and epilepsy. It also provides a novel method for the treatment, prevention, and research of epilepsy, to control epileptic seizures and reduce nerve injury after the epileptic seizure.

High ability of zileuton ((±)-1-(1-benzo[b]thien-2-ylethyl)-1-hydroxyurea) to stimulate IK(Ca) but suppress IK(DR) and IK(M) independently of 5-lipoxygenase inhibition

Zileuton (Zyflo®) is regarded to be an inhibitor of 5-lipoxygenase. Although its effect on Ca2+-activated K+ currents has been reported, its overall ionic effects on neurons are uncertain. In whole-cell current recordings, zileuton increased the amplitude of Ca2+-activated K+ currents with an EC50 of 3.2 μM in pituitary GH3 lactotrophs. Furthermore, zileuton decreased the amplitudes of both delayed-rectifier K+ current (IK(DR)) and M-type K+ current (IK(M)). Conversely, no modification of hyperpolarization-activated cation current (Ih) was demonstrated in its presence of zileuton, although the subsequent addition of cilobradine effectively suppressed the current. In inside-out current recordings, the addition of zileuton to the bath increased the probability of large-conductance Ca2+-activated K+ (BKCa) channels; however, the subsequent addition of GAL-021 effectively reversed the stimulation of channel activity. The kinetic analyses showed an evident shortening in the slow component of mean closed time of BKCa channels in the presence of zileuton, with minimal change in mean open time or that in the fast component of mean closed time. The elevation of BKCa channels caused by zileuton was also observed in hippocampal mHippoE-14 neurons, without any modification of single-channel amplitude. In conclusion, except for its suppression of 5-lipoxygenase, our results indicate that zileuton does not exclusively act on BKCa channels, and its inhibitory effects on IK(DR) and IK(M) may combine to exert strong influence on the functional activities of electrically excitable cells in vivo.

Mechanism of Ferroptosis and Its Relationships With Other Types of Programmed Cell Death: Insights for Potential Interventions After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a fatal cerebrovascular disease with high morbidity and mortality, for which no effective therapies are currently available. Brain tissue damage caused by ICH is mediated by a newly identified form of non-apoptotic programmed cell death, called ferroptosis. Ferroptosis is characterized by the iron-induced accumulation of lipid reactive oxygen species (ROS), leading to intracellular oxidative stress. Lipid ROS cause damage to nucleic acids, proteins, and cell membranes, eventually resulting in ferroptosis. Numerous biological processes are involved in ferroptosis, including iron metabolism, lipid peroxidation, and glutathione biosynthesis; therefore, iron chelators, lipophilic antioxidants, and other specific inhibitors can suppress ferroptosis, suggesting that these modulators are beneficial for treating brain injury due to ICH. Accumulating evidence indicates that ferroptosis differs from other types of programmed cell death, such as necroptosis, apoptosis, oxytosis, and pyroptosis, in terms of ultrastructural characteristics, signaling pathways, and outcomes. Although several studies have emphasized the importance of ferroptosis due to ICH, the detailed mechanism underlying ferroptosis remains unclear. This review summarizes the available evidence on the mechanism underlying ferroptosis and its relationship with other types of cell death, with the aim to identify therapeutic targets and potential interventions for ICH.

Docking Studies and Molecular Dynamics Simulation of Ipomoea batatas L. Leaves Compounds as Lipoxygenase (LOX) Inhibitor

Background

Inflammatory mediators produced by cyclooxygenase (COX) and lipoxygenase (LOX) pathways are responsible for many human diseases, such as cancer, arthritis, and neurological disorders. Flavonoid-containing plants, such as Ipomoea batatas leaves, have shown potential anti-inflammatory activity.

Objectives

This study aimed to predict the actions of 10 compounds in I. batatas leaves, which are YGM-0a [cyanidin 3-0-sophoroside-5-0-glucosede], YGM-0f [cyanidin 3-O-(2-0-(6-0-(E)-p-coumaroyl-β-D-glucopyranosyl)-β-D-glucopyranoside)-5-0-β-D-glucopyranoside], YGM-1a [cyanidin 3-(6,6'-caffeylp-hydroxybenzoylsophoroside) -5-glucoside], YGM-1b [cyanidin 3-(6,6'-dicaffeylsophor-oside)-5-glucoside], YGM-2 [cyanidin 3-(6-caffeylsophoroside)-5-glucoside], YGM-3 [cyanidin 3-(6,6'-caffeyl-ferulylsophoroside)-5-glucoside], YGM-4b [peonidin 3-(6,6'-dicaffeylsophoroside)-5- glucoside], YGM-5a [peonidin 3-(6,6'-caffeylphydroxybenzo-ylsophoroside)-5-gluco-side], YGM-5b [cyanidin 3-6-caffeylsophoroside)-5-glucosede], and YGM-6 [peonidin 3-(6,6'-caffeylferulylsophoroside)-5-glucoside] as LOX inhibitors, and also predict the stability of ligand-LOX complex.

Materials and Methods

The compounds were screened through docking studies using PLANTS. Also, the molecular dynamics simulation was conducted using GROMACS at 310K.

Results

The results showed that the most significant binding affinity toward LOX was shown by YGM-0a and YGM-0a, and the LOX complex in molecular dynamics simulation showed stability for 20 ns.

Conclusion

Based on Docking Studies and Molecular Dynamics Simulation of I. Batatas Leaves compounds, YGM-0a was shown to be the most probable LOX inhibitor.

Novel insights into ferroptosis: Implications for age-related diseases

Rapid increase in aging populations is an urgent problem because older adults are more likely to suffer from disabilities and age-related diseases (ARDs), burdening healthcare systems and society in general. ARDs are characterized by the progressive deterioration of tissues and organs over time, eventually leading to tissue and organ failure. To date, there are no effective interventions to prevent the progression of ARDs. Hence, there is an urgent need for new treatment strategies. Ferroptosis, an iron-dependent cell death, is linked to normal development and homeostasis. Accumulating evidence, however, has highlighted crucial roles for ferroptosis in ARDs, including neurodegenerative and cardiovascular diseases. In this review, we a) summarize initiation, regulatory mechanisms, and molecular signaling pathways involved in ferroptosis, b) discuss the direct and indirect involvement of the activation and/or inhibition of ferroptosis in the pathogenesis of some important diseases, and c) highlight therapeutic targets relevant for ARDs.

Aluminum maltolate triggers ferroptosis in neurons: mechanism of action

Aluminum (Al), a neurotoxic element, can induce Alzheimer's disease (AD) via triggering neuronal death. Ferroptosis is a new type of programmed cell death related to neurological diseases. Unfortunately, its role in aluminum-induced neuronal death remains completely unclear. This study aimed to investigate whether ferroptosis is involved in neuronal death in response to aluminum exposure as well as its underlying mechanism. In this study, rat adrenal pheochromocytoma (PC12) cells were treated with 200 μM aluminum maltolate (Al(mal)₃) for 24 h, and related biochemical indicators were assessed to determine whether ferroptosis was induced by aluminum in neurons. Then, the potential mechanism was explored by detecting of these genes and proteins associated with ferroptosis after adding ferroptosis-specific agonist Erastin (5 μM) and antagonist Ferrostatin-1 (Fer-1) (5 μM). The experimental results demonstrated that aluminum exposure significantly increased the death of PC12 cells and caused specific mitochondrial pathological changes of ferroptosis in PC12 cells. Further research confirmed that ferroptosis was triggered by aluminum in PC12 cells by means of activating the oxidative damage signaling pathway, which was displayed as inhibition of the cysteine/glutamate antiporter system (system Xc^-), causing the depletion of cellular glutathione (GSH) and inactivation of glutathione peroxidase (GSH-PX) eventually lead to accumulation of reactive oxygen species (ROS). Taken together, ferroptosis was a means of neuronal death induced by aluminum and oxidative damage may be its underlying mechanism, which also provided some new clues to potential target for the intervention and therapy of AD.

Crosstalk Between Autophagy and Ferroptosis and Its Putative Role in Ischemic Stroke

Autophagy is a conserved process to maintains homeostasis via the degradation of toxic cell contents, which can either promote cell survival or accelerate cellular demise. Ferroptosis is a recently discovered iron-dependent cell death pathway associated with the accumulation of lethal reactive lipid species. In the past few years, an increasing number of studies have suggested the crosstalk between autophagy and ferroptosis. Ischemic stroke is a complex brain disease regulated by several cell death pathways, including autophagy and ferroptosis. However, the potential links between autophagy and ferroptosis in ischemic stroke have not yet been explored. In this review, we briefly overview the mechanisms of ferroptosis and autophagy, as well as their possible connections in ischemic stroke. The elucidation of crosstalk between different cell death pathways may provide insight into new future ischemic stroke therapies.

Ferroptosis mediated by the interaction between Mfn2 and IREα promotes arsenic-induced nonalcoholic steatohepatitis

Exposure to arsenic is a risk factor for nonalcoholic steatohepatitis (NASH). Ferroptosis is a form of regulated cell death defined by the accumulation of lipid peroxidation. In the current study, we observed the occurrence of ferroptosis in arsenic-induced NASH by assessing ferroptosis related hallmarks. In vitro, we found that ferrostatin-1 effectively attenuated the executing of ferroptosis and NASH. Simultaneously, the expression of ACSL4 (acyl-CoA synthetase long-chain family member 4) was upregulated in rat's liver and L-02 cells exposed to arsenic. While, suppression of ACSL4 with rosiglitazone or ACSL4 siRNA remarkably alleviated arsenic-induced NASH and ferroptosis through diminishing 5-hydroxyeicosatetraenoic acid (5-HETE) content. Additionally, Mitofusin 2 (Mfn2), a physical tether between endoplasmic reticulum and mitochondria, has rarely been explored in the ferroptosis. Using Mfn2 siRNA or inositol-requiring enzyme 1 alpha (IRE1α) inhibitor, we found NASH and ferroptosis were obviously mitigated through reducing 5-HETE content. Importantly, Co-IP assay indicated that Mfn2 could interact with IRE1α and promoted the production of 5-HETE, ultimately led to ferroptosis and NASH. Collectively, our data showed that ferroptosis is involved in arsenic-induced NASH. These data provide insightful viewpoints into the mechanism of arsenic-induced NASH.