AMID, an apoptosis-inducing factor-homologous mitochondrion-associated protein, induces caspase-independent apoptosis

An apoptosis-inducing factor controls programmed cell death and laccase expression during fungal interactions

Apoptotic-like programmed cell death (PCD) is one of the main strategies for fungi to resist environmental stresses and maintain homeostasis. The apoptosis-inducing factor (AIF) has been shown in different fungi to trigger PCD through upregulating reactive oxygen species (ROS). This study identified a mitochondrial localized AIF homolog, CcAIF1, from Coprinopsis cinerea monokaryon Okayama 7. Heterologous overexpression of CcAIF1 in Saccharomyces cerevisiae caused apoptotic-like PCD of the yeast cells. Ccaif1 was increased in transcription when C. cinerea interacted with Gongronella sp. w5, accompanied by typical apoptotic-like PCD in C. cinerea, including phosphatidylserine externalization and DNA fragmentation. Decreased mycelial ROS levels were observed in Ccaif1 silenced C. cinerea transformants during cocultivation, as well as reduction of the apoptotic levels, mycelial growth, and asexual sporulation. By comparison, Ccaif1 overexpression led to the opposite phenotypes. Moreover, the transcription and expression levels of laccase Lcc9 decreased by Ccaif1 silencing but increased firmly in Ccaif1 overexpression C. cinerea transformants in coculture. Thus, in conjunction with our previous report that intracellular ROS act as signal molecules to stimulate defense responses, we conclude that CcAIF1 is a regulator of ROS to promote apoptotic-like PCD and laccase expression in fungal-fungal interactions. In an axenic culture of C. cinerea, CcAIF1 overexpression and H2O2 stimulation together increased laccase secretion with multiplied production yield. The expression of two other normally silent isozymes, Lcc8 and Lcc13, was unexpectedly triggered along with Lcc9. KEY POINTS: • Mitochondrial CcAIF1 induces PCD during fungal-fungal interactions • CcAIF1 is a regulator of ROS to trigger the expression of Lcc9 for defense • CcAIF1 overexpression and H2O2 stimulation dramatically increase laccase production.

Targeting ferroptosis suppressor protein 1 in cancer therapy: Implications and perspectives, with emphasis on head and neck cancer

The diverse functions of ferroptosis suppressor protein 1 (FSP1/AIFM2) in cancer have positioned it as a promising therapeutic target across various malignancies, including head and neck cancer (HNC). Initially characterized as a potential tumor suppressor due to its involvement in apoptosis and ferroptosis, recent studies have revealed its complex role in tumor growth, metabolism, and therapy resistance. Pharmacological inhibition of FSP1 shows potential in sensitizing cancer cells to ferroptosis and overcoming resistance to conventional therapies, offering new avenues for precision medicine approaches. Identifying novel FSP1 inhibitors and their synergistic effects with existing therapies presents exciting opportunities for therapeutic development. However, translating preclinical findings into clinical practice requires the refinement of FSP1 inhibitors, robust biomarkers for patient stratification, and further investigations into the molecular mechanisms underlying FSP1-mediated therapy resistance. Integrating FSP1-targeted therapies into comprehensive treatment regimens holds promise for improving outcomes in cancer patients and advancing the field of precision oncology.

Research progress of ferroptosis and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a non-specific chronic inflammatory disorder of the gastrointestinal tract, imposing significant burdens on both society and individuals. As a new type of regulated cell death (RCD), ferroptosis is different from classic RCDs such as apoptosis and necrosis in cell morphology, biochemistry and genetics. The main molecular mechanisms of ferroptosis include dysregulation of iron metabolism, impaired antioxidant capacity, mitochondrial dysfunction, accumulation of lipid-associated super-oxides, and membrane disruption. In recent years, increasing evidence has shown that ferroptosis is involved in the pathophysiology of inflammatory bowel disease. However, the exact roles and underlying molecular mechanisms have not been fully elucidated. This article reviews the mechanism of ferroptosis in the occurrence and development of inflammatory bowel disease, in order to provide new ideas for the pathophysiological research of inflammatory bowel disease. Additionally, we discuss potential strategies for the prevention and treatment of inflammatory bowel disease by targeting ferroptosis.

Ferroptosis Inhibition: A Key Opportunity for the Treatment of Ischemia/Reperfusion Injury in Liver Transplantation

The outcome after liver transplantation has improved in recent years, which can be attributed to superior storage and transportation conditions of the organs, as well as better peri- and postoperative management and advancements in surgical techniques. Nevertheless, there is an increasing discrepancy between the need for organs and their availability. Consequently, the mortality rate on the waiting list is high and continues to rise. One way of counteracting this trend is to increase the use of "expanded criteria donors." This means that more and more donors will be included, especially those who are older and having additional comorbidities (eg, steatosis). A major complication of any transplantation is the occurrence of ischemia/reperfusion injury (IRI), which often leads to liver dysfunction and failure. However, there have been various promising approaches to minimize IRI in recent years, but an effective and clinically applicable method to achieve a better outcome for patients after liver transplantation is still missing. Thereby, the so-called marginal organs are predominantly affected by IRI; thus, it is crucial to develop suitable and effective treatment options for patients. Recently, regulated cell death mechanisms, particularly ferroptosis, have been implicated to play a major role in IRI, including the liver. Therefore, inhibiting this kind of cell death modality presents a promising therapeutic approach for the management of this yet untreatable condition. Thus, this review provides an overview of the role of ferroptosis in liver IRI and transplantation and discusses possible therapeutic solutions based on ferroptosis inhibition to restrain IRI in marginal organs (especially steatosis and donation after circulatory death organs).

FSP1-mediated ferroptosis in cancer: from mechanisms to therapeutic applications

Ferroptosis is a new discovered regulated cell death triggered by the ferrous ion (Fe2+)-dependent accumulation of lipid peroxides associated with cancer and many other diseases. The mechanism of ferroptosis includes oxidation systems (such as enzymatic oxidation and free radical oxidation) and antioxidant systems (such as GSH/GPX4, CoQ10/FSP1, BH4/GCH1 and VKORC1L1/VK). Among them, ferroptosis suppressor protein 1 (FSP1), as a crucial regulatory factor in the antioxidant system, has shown a crucial role in ferroptosis. FSP1 has been well validated to ferroptosis in three ways, and a variety of intracellular factors and drug molecules can alleviate ferroptosis via FSP1, which has been demonstrated to alter the sensitivity and effectiveness of cancer therapies, including chemotherapy, radiotherapy, targeted therapy and immunotherapy. This review aims to provide important frameworks that, bring the regulation of FSP1 mediated ferroptosis into cancer therapies on the basis of existing studies.

The dual role of FSP1 in programmed cell death: resisting ferroptosis in the cell membrane and promoting necroptosis in the nucleus of THP-1 cells

BACKGROUND

Acute monocytic leukemia-M5 (AML-M5) remains a challenging disease due to its high morbidity and poor prognosis. In addition to the evidence mentioned earlier, several studies have shown that programmed cell death (PCD) serves a critical function in treatment of AML-M5. However, the role and relationship between ferroptosis and necroptosis in AML-M5 remains unclear.

METHODS

THP-1 cells were mainly treated with Erastin and IMP-366. The changes of ferroptosis and necroptosis levels were detected by CCK-8, western blot, quantitative real-time PCR, and electron microscopy. Flow cytometry was applied to detect the ROS and lipid ROS levels. MDA, 4-HNE, GSH and GSSG were assessed by ELISA kits. Intracellular distribution of FSP1 was studied by immunofluorescent staining and western blot.

RESULTS

The addition of the myristoylation inhibitor IMP-366 to erastin-treated acute monocytic leukemia cell line THP-1 cell not only resulted in greater susceptibility to ferroptosis characterized by lipid peroxidation, glutathione (GSH) depletion and mitochondrial shrinkage, as the FSP1 position on membrane was inhibited, but also increased p-RIPK1 and p-MLKL protein expression, as well as a decrease in caspase-8 expression, and triggered the characteristic necroptosis phenomena, including cytoplasmic translucency, mitochondrial swelling, membranous fractures by FSP1 migration into the nucleus via binding importin α2. It is interesting to note that ferroptosis inhibitor fer-1 reversed necroptosis.

CONCLUSION

We demonstrated that inhibition of myristoylation by IMP-366 is capable of switching ferroptosis and ferroptosis-dependent necroptosis in THP-1 cells. In these findings, FSP1-mediated ferroptosis and necroptosis are described as alternative mechanisms of PCD of THP-1 cells, providing potential therapeutic strategies and targets for AML-M5.

Canagliflozin Inhibits Palmitic Acid-Induced Vascular Cell Aging In Vitro through ROS/ERK and Ferroptosis Pathways

Vascular aging is one of the reasons for the high incidence of cardiovascular diseases nowadays, as vascular cells age due to various internal and external factors. Among them, high fat is an important inducer. Canagliflozin (CAN) is one of the SGLT2 inhibitors that has been shown to have cardiovascular protective effects in addition to lowering blood sugar, but the specific mechanism is not clear. This study first established a vascular aging model using palmitic acid (PA), then tested the effect of CAN on PA-induced vascular aging, and finally examined the mechanism of CAN's anti-vascular aging via ROS/ERK and ferroptosis pathways. We found that CAN alleviates PA-induced vascular cell aging by inhibiting the activation of ROS/ERK and ferroptosis signaling pathways. This study reveals new mechanisms of lipid-induced vascular aging and CAN inhibition of vascular aging from the perspectives of ROS/ERK and ferroptosis pathways, which is expected to provide new ideas for the development of related drugs in the future.

Ferroptosis in cancer (Review)

Ferroptosis is a type of programmed cell death depending on iron and reactive oxygen species. This unique cell death process has attracted a great deal of attention in the field of cancer research over the past decade. Research on the association of ferroptosis signal pathways and cancer development indicated that targeting ferroptosis has great potential for cancer therapy. In the present study, the latest research progress of ferroptosis was reviewed, focusing on the relationship between ferroptosis and the development of cancer, in order to further promote the clinical application of ferroptosis in cancer.

Ferroptosis defense mechanisms: The future and hope for treating osteosarcoma

Currently, challenges such as chemotherapy resistance, resulting from preoperative and postoperative chemotherapy, postoperative recurrence, and poor bone regeneration quality, are becoming increasingly prominent in osteosarcoma (OS) treatment. There is an urgent need to find more effective ways to address these issues. Ferroptosis is a novel form of iron-dependent programmed cell death, distinct from other forms of cell death. In this paper, we summarize how, through the three major defense systems of ferroptosis, not only can substances from traditional Chinese medicine, antitumor drugs, and nano-drug carriers induce ferroptosis in OS cells, but they can also be combined with immunotherapy, differentiation therapy, and other treatment modalities to significantly enhance chemotherapy sensitivity and inhibit tumor growth. Thus, ferroptosis holds great potential in treating OS, offering more choices and possibilities for future clinical interventions.

Research update for ferroptosis and cholangiocarcinoma

Cholangiocarcinoma (CCA) is the second most common hepatobiliary malignancy after hepatocellular carcinoma. Due to the poor treatment effect and high mortality rate of CCA, it is of great significance to explore new therapeutic targets. Ferroptosis is a type of cell death caused by iron-dependent cell oxidative injury, which is closely related to the occurrence and development of numerous diseases. Novel ideas for the prevention and treatment of related diseases have been provided by ferroptosis, which has become a focus of research in recent years. This review introduces the underlying mechanisms related to ferroptosis, as well as a research update for ferroptosis in the occurrence and development of CCA. The clinical value of ferroptosis-related regulatory mechanisms in CCA will be elucidated.

Knockdown of NADK promotes LUAD ferroptosis via NADPH/FSP1 axis

BACKGROUND

Lung cancer is a serious threat to human health and is the first leading cause of cancer death. Ferroptosis, a newly discovered form of programmed cell death associated with redox homeostasis, is of particular interest in the lung cancer, given the high oxygen environment of lung cancer. NADPH has reducing properties and therefore holds the potential to resist ferroptosis. Resistance to ferroptosis exists in lung cancer, but the role of NADK in regulating ferroptosis in lung cancer has not been reported yet.

METHODS

Immunohistochemistry (IHC) was used to analyse the expression of NADK in 86 cases of lung adenocarcinoma(LUAD) and adjacent tissues, and a IHC score was assigned to each sample. Chi-square and kaplan-meier curve was performed to analyse the differences in metastasis and five-year survival between the two groups with NADK high or low scores. Proliferation of NADK-knockdown LUAD cell lines was detected in vivo and vitro. Furthermore, leves of ROS, MDA and Fe2+ were measured to validate the effect and mechanism of NADK on ferroptosis in LUAD.

RESULTS

The expression of NADK was significantly evaluated in LUAD tissues as compared to adjacent non-cancerous tissues. The proliferation of NADK-knockdown cells was inhibited both in vivo and vitro, and increasing levels of intracellular ROS, Fe2+ and lipid peroxide products (MDA) were observed. Furthermore, NADK-knockdown promoted the ferroptosis of LUAD cells induced by Erastin/RSL3 by regulating the level of NADPH and the expression of FSP1. Knockdown of NADK enhanced the sensitivities of LUAD cells to Erastin/RSL3-induced ferroptosis by regulating NADPH level and FSP1 expression.

CONCLUSIONS

NADK is over-expressed in LUAD patients. Knockdown of NADK inhibited the proliferation of LUAD cells both in vitro and in vivo and promotes the Erastin/RSL3-induced ferroptosis of LUAD cells by down-regulating the NADPH/FSP1 axis.

Ferroptosis: a potential therapeutic target for stroke

Ferroptosis is a form of regulated cell death characterized by massive iron accumulation and iron-dependent lipid peroxidation, differing from apoptosis, necroptosis, and autophagy in several aspects. Ferroptosis is regarded as a critical mechanism of a series of pathophysiological reactions after stroke because of iron overload caused by hemoglobin degradation and iron metabolism imbalance. In this review, we discuss ferroptosis-related metabolisms, important molecules directly or indirectly targeting iron metabolism and lipid peroxidation, and transcriptional regulation of ferroptosis, revealing the role of ferroptosis in the progression of stroke. We present updated progress in the intervention of ferroptosis as therapeutic strategies for stroke in vivo and in vitro and summarize the effects of ferroptosis inhibitors on stroke. Our review facilitates further understanding of ferroptosis pathogenesis in stroke, proposes new targets for the treatment of stroke, and suggests that more efforts should be made to investigate the mechanism of ferroptosis in stroke.

Apoptosis-inducing factor 1 mediates Vibrio splendidus-induced coelomocyte apoptosis via importin β dependent nuclear translocation in Apostichopus japonicus

As is well known, apoptosis is an important form of immune response and immune regulation, particularly playing a crucial role in combating microbial infections. Apoptosis-inducing factor 1 (AIF-1) is essential for apoptosis to induce chromatin condensation and DNA fragmentation via a caspase-independent pathway. The nuclear translocation of AIF-1 is a key step in apoptosis but the molecular mechanism is still unclear. In this study, the homologous gene of AIF-1, named AjAIF-1, was cloned and identified in Apostichopus japonicus. The mRNA expression of AjAIF-1 was significantly increased by 46.63-fold after Vibrio splendidus challenge. Silencing of AjAIF-1 was found to significantly inhibit coelomocyte apoptosis because the apoptosis rate of coelomocyte decreased by 0.62-fold lower compared with the control group. AjAIF-1 was able to promote coelomocyte apoptosis through nuclear translocation under the V. splendidus challenge. Moreover, AjAIF-1 and Ajimportin β were mainly co-localized around the nucleus in vivo and silencing Ajimportin β significantly inhibited the nuclear translocation of AjAIF-1 and suppressed coelomocyte apoptosis by 0.64-fold compared with control. In summary, nuclear translocation of AjAIF-1 will likely mediate coelomocyte apoptosis through an importin β-dependent pathway in sea cucumber.

Molecular mechanism of ATF6 in unfolded protein response and its role in disease

Activating transcription factor 6 (ATF6), an important signaling molecule in unfolded protein response (UPR), plays a role in the pathogenesis of several diseases, including diseases such as congenital retinal disease, liver fibrosis and ankylosing spondylitis. After endoplasmic reticulum stress (ERS), ATF6 is activated after separation from binding immunoglobulin protein (GRP78/BiP) in the endoplasmic reticulum (ER) and transported to the Golgi apparatus to be hydrolyzed by site 1 and site 2 proteases into ATF6 fragments, which localize to the nucleus and regulate the transcription and expression of ERS-related genes. In these diseases, ERS leads to the activation of UPR, which ultimately lead to the occurrence and development of diseases by regulating the physiological state of cells through the ATF6 signaling pathway. Here, we discuss the evidence for the pathogenic importance of ATF6 signaling in different diseases and discuss preclinical results.

Ferroptosis: Emerging mechanisms, biological function, and therapeutic potential in cancer and inflammation

Ferroptosis represents a distinct form of programmed cell death triggered by excessive iron accumulation and lipid peroxidation-induced damage. This mode of cell death differentiates from classical programmed cell death in terms of morphology and biochemistry. Ferroptosis stands out for its exceptional biological characteristics and has garnered extensive research and conversations as a form of programmed cell death. Its dysfunctional activation is closely linked to the onset of diseases, particularly inflammation and cancer, making ferroptosis a promising avenue for combating these conditions. As such, exploring ferroptosis may offer innovative approaches to treating cancer and inflammatory diseases. Our review provides insights into the relevant regulatory mechanisms of ferroptosis, examining the impact of ferroptosis-related factors from both physiological and pathological perspectives. Describing the crosstalk between ferroptosis and tumor- and inflammation-associated signaling pathways and the potential of ferroptosis inducers in overcoming drug-resistant cancers are discussed, aiming to inform further novel therapeutic directions for ferroptosis in relation to inflammatory and cancer diseases.

CD36 promotes tubular ferroptosis by regulating the ubiquitination of FSP1 in acute kidney injury

Reactive oxidative species (ROS) production-driven ferroptosis plays a role in acute kidney injury (AKI). However, its exact molecular mechanism is poorly understood. Scavenger receptor CD36 has important roles in oxidizing lipids, lipid accumulation, metabolic syndrome, and insulin resistance in chronic kidney disease, but its roles remain unexplored in AKI. The present study investigated the role and mechanism of CD36 in regulating proximal tubular cell ferroptosis and AKI. The expression of CD36 was found to be significantly up-regulated in AKI renal tissues and correlated with renal function, which might serve as an independent biomarker for AKI patients. Moreover, in adult mice subjected to AKI, deletion of CD36 (CD36-/-) induced tubular cell ROS accumulation, ferroptosis activation, and renal injury. Mechanistically, combining LC-MS/MS, co-IP, and ubiquitination analyses revealed that CD36 could specifically bind to ferroptosis suppressor protein 1 (FSP1) and regulate its ubiquitination at sites K16 and K24, leading to FSP1 degradation and progression of ferroptosis in AKI. The present results emphasize a novel mechanism of CD36 in cisplatin-induced AKI. The discovery of the special CD36 roles in promoting ferroptosis and AKI development by regulating the ubiquitination of FSP1 in proximal tubular cells may be potential therapeutic targets for AKI. Moreover, CD36 may play a key role in the progression of AKI. Therefore, targeting CD36 may provide a promising treatment option for AKI.

The mitochondrial regulation in ferroptosis signaling pathway and its potential strategies for cancer

Ferroptosis is an iron-dependent regulated cell death, mainly manifested by the production of reactive oxygen species and accumulation of lipid peroxides. It is distinct from other forms of cell death with regard to morphology and biochemistry, particularly in disrupting mitochondrial function. Mitochondria are essential compartments where the organism generates energy and are closely associated with the fate of ferroptosis. Currently, researchers focus on the potential value of ferroptosis and mitochondria for overcoming drug sensitivity and assisting in cancer therapy. In this review, we summarize the main mechanisms of ferroptosis (the GPX4-realated pathway, FSP1-related pathway, and iron metabolism pathway) and the functions and regulating pathways of mitochondria (the TCA cycle, oxidative phosphorylation, mitochondrial regulation of iron ions, and mtDNA) in ferroptosis. We believe that exploring the role of mitochondria in ferroptosis will help us understand the potential regulatory mechanisms of ferroptosis in cancer and help us find new therapeutic targets.

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.

The emerging role of ferroptosis in female reproductive disorders

Iron, as an essential trace element for the organism, is vital for maintaining the organism's health. Excessive iron can promote reactive oxygen species (ROS) accumulation, thus damaging cells and tissues. Ferroptosis is a novel form of programmed cell death distinguished by iron overload and lipid peroxidation, which is unique from autophagy, apoptosis and necrosis, more and more studies are focusing on ferroptosis. Recent evidence suggests that ferroptosis is associated with the development of female reproductive disorders (FRDs), including polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), endometriosis (EMs), ovarian cancer (OC), preeclampsia (PE) and spontaneous abortion (SA). Pathways and genes associated with ferroptosis may participate in processes that regulate granulosa cell proliferation and secretion, oocyte development, ovarian reserve function, early embryonic development and placental oxidative stress. However, its exact mechanism has not been fully revealed. Therefore, our review systematically elaborates the occurrence mechanism of ferroptosis and its research progress in the development of FRDs, with a view to providing literature references for clinical targeting of ferroptosis -related pathways and regulatory factors for the management of FRDs.

Sorafenib induces ferroptosis by promoting TRIM54-mediated FSP1 ubiquitination and degradation in hepatocellular carcinoma

BACKGROUND

Ferroptosis is a unique form of regulated cell death that provided a new opportunity for cancer therapy. Ferroptosis suppressor protein 1 (FSP1) is a key regulator in the NAD(P)H/FSP1/CoQ10 antioxidant system, which sever as an oxide redox enzyme to scavenge harmful lipid hydroperoxides and escape from ferroptosis in cells. This study aimed to investigate the role of FSP1 on sorafenib-induced ferroptosis and disclosed the underlying mechanisms.

METHODS

Cell viability, malondialdehyde (MDA), glutathione (GSH), and lipid reactive oxygen species levels were assessed using indicated assay kits. The levels of FSP1 and glutathione peroxidase 4 (GPX4) in the patients with HCC were analyzed based on the database. Western blot and quantitative real-time PCR were performed to detect the protein and mRNA expression. Co-immunoprecipitation was applied to detect the interaction between proteins. Tumor xenograft experiments were used to evaluate whether overexpression of FSP1-inhibited sorafenib-induced ferroptosis in vivo.

RESULTS

We verified that sorafenib-induced ferroptosis in HCC. Furthermore, we found that sorafenib decreased the protein level of FSP1, and knockdown FSP1 rendered HCC cells susceptible to sorafenib-induced ferroptosis. Co-immunoprecipitation and ubiquitination assays showed that sorafenib accelerated the TRIM54-mediated FSP1 ubiquitination and degradation. Sorafenib-induced ferroptosis was abrogated by TRIM54 suppression. Mechanically, sorafenib-promoted TRIM54 ubiquitinated and degraded FSP1 by means of the ERK pathway. Moreover, FSP1 enhanced tumor development and decreased HCC cellular susceptibility to sorafenib in vivo.

CONCLUSIONS

Sorafenib facilitated the TRIM54-mediated FSP1 ubiquitination through the ERK pathway, thereby inducing ferroptosis in HCC cells.

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.

Structural insights into FSP1 catalysis and ferroptosis inhibition

Ferroptosis suppressor protein 1 (FSP1, also known as AIMF2, AMID or PRG3) is a recently identified glutathione-independent ferroptosis suppressor1-3, but its underlying structural mechanism remains unknown. Here we report the crystal structures of Gallus gallus FSP1 in its substrate-free and ubiquinone-bound forms. The structures reveal a FAD-binding domain and a NAD(P)H-binding domain, both of which are shared with AIF and NADH oxidoreductases4-9, and a characteristic carboxy-terminal domain as well. We demonstrate that the carboxy-terminal domain is crucial for the catalytic activity and ferroptosis inhibition of FSP1 by mediating the functional dimerization of FSP1, and the formation of two active sites located on two sides of FAD, which are responsible for ubiquinone reduction and a unique FAD hydroxylation respectively. We also identify that FSP1 can catalyze the production of H2O2 and the conversion of FAD to 6-hydroxy-FAD in the presence of oxygen and NAD(P)H in vitro, and 6-hydroxy-FAD directly inhibits ferroptosis in cells. Together, these findings further our understanding on the catalytic and ferroptosis suppression mechanisms of FSP1 and establish 6-hydroxy-FAD as an active cofactor in FSP1 and a potent radical-trapping antioxidant in ferroptosis inhibition.

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.

FSP1: a key regulator of ferroptosis

Ferroptosis suppressor protein 1 (FSP1) is one of the main regulatory molecules of ferroptosis. FSP1 functions through the FSP1-coenzyme Q10 (CoQ10)-NAD(P)H axis and the vitamin K redox cycle. FSP1 is regulated by upstream factors, including transcription factors and noncoding RNA (ncRNA), and is subject to epigenetic modifications, which affect the progress of FSP1-related diseases. FSP1 is closely associated with the poor prognosis of malignant tumors and plays an important role in disease treatment. This review aims to provide a comprehensive understanding of the role of FSP1 in ferroptosis regulation by summarizing regulatory pathways, possible mechanisms involving FSP1, and the relationship between FSP1 and disease prognosis and treatment.

Basic mechanisms and novel potential therapeutic targets for ferroptosis in acute myeloid leukemia

Ferroptosis is a form of cell death that is regulated by iron and characterized by the buildup of lipid peroxides (LPO) and subsequent rupture of the cell membrane. The molecular mechanisms of ferroptosis involve metabolic pathways related to iron, lipids, and amino acids, which contribute to the production of lipid reactive oxygen species (ROS). In recent years, there has been increasing attention on the occurrence of ferroptosis in various diseases. Ferroptosis has been found to play a crucial role in cardiovascular diseases, digestive diseases, respiratory and immunological diseases, and particularly in malignancies. However, there is still a lack of studies on ferroptosis in acute myeloid leukemia (AML). This paper provides a comprehensive review of the mechanism of ferroptosis and its regulatory molecules and therapeutic agents in AML. It also evaluates the relationship between ferroptosis-related genes (FRGs), non-coding RNAs (ncRNAs), and prognosis to develop prognostic molecular models in AML. The study also explores the association between ferroptosis and immune infiltration in AML, to identify novel potential target regimens for AML.

Unleashing Ferroptosis in Human Cancers: Targeting Ferroptosis Suppressor Protein 1 for Overcoming Therapy Resistance

Ferroptosis, a recently identified form of regulated cell death characterized by the iron-dependent accumulation of lethal lipid peroxidation, has gained increasing attention in cancer therapy. Ferroptosis suppressor protein 1 (FSP1), an NAD(P)H-ubiquinone oxidoreductase that reduces ubiquinone to ubiquinol, has emerged as a critical player in the regulation of ferroptosis. FSP1 operates independently of the canonical system xc^-/glutathione peroxidase 4 pathway, making it a promising target for inducing ferroptosis in cancer cells and overcoming ferroptosis resistance. This review provides a comprehensive overview of FSP1 and ferroptosis, emphasizing the importance of FSP1 modulation and its potential as a therapeutic target in cancer treatment. We also discuss recent progress in developing FSP1 inhibitors and their implications for cancer therapy. Despite the challenges associated with targeting FSP1, advances in this field may provide a strong foundation for developing innovative and effective treatments for cancer and other diseases.

Targeting ferroptosis, a novel programmed cell death, for the potential of alcohol-related liver disease therapy

Ferroptosis is a new iron-dependent cell death mode, which is different from the other types of programmed cell death, such as apoptosis, necrosis, and autophagy. Ferroptosis is characterized by a process in which fatal lipids from lipid peroxidation accumulate in cells and eventually lead to cell death. Alcohol-related liver disease (ALD) is a type of liver injury caused by excessive alcohol intake. Alcohol-related liver disease is a broad-spectrum disease category, which includes fatty liver, steatohepatitis, hepatitis, cirrhosis, and hepatocellular tumors. Recent studies have found that ferroptosis is involved in the pathological development of non-viral liver diseases. Therefore, ferroptosis may be an ideal target for the treatment of non-viral liver diseases. In this review article, we will elaborate the molecular mechanism and regulatory mechanism of ferroptosis, explore the key role of ferroptosis in the Alcohol-related liver disease process, and summarize the existing targeted ferroptosis drugs and their feasibility for the treatment of Alcohol-related liver disease.

The role of ferroptosis in metabolic diseases

The annual incidence of metabolic diseases such as diabetes, non-alcoholic fatty liver disease (NAFLD), osteoporosis, and atherosclerosis (AS) is increasing, resulting in a heavy burden on human health and the social economy. Ferroptosis is a novel form of programmed cell death driven by iron-dependent lipid peroxidation, which was discovered in recent years. Emerging evidence has suggested that ferroptosis contributes to the development of metabolic diseases. Here, we summarize the mechanisms and molecular signaling pathways involved in ferroptosis. Then we discuss the role of ferroptosis in metabolic diseases. Finally, we analyze the potential of targeting ferroptosis as a promising therapeutic approach for metabolic diseases.

Ferroptosis in acute leukemia

ABSTRACT

Ferroptosis is an iron-dependent cell death pathway that is different from apoptosis, pyroptosis, and necrosis. The main characteristics of ferroptosis are the Fenton reaction mediated by intracellular free divalent iron ions, lipid peroxidation of cell membrane lipids, and inhibition of the anti-lipid peroxidation activity of intracellular glutathione peroxidase 4 (GPX4). Recent studies have shown that ferroptosis can be involved in the pathological processes of many disorders, such as ischemia-reperfusion injury, nervous system diseases, and blood diseases. However, the specific mechanisms by which ferroptosis participates in the occurrence and development of acute leukemia still need to be more fully and deeply studied. This article reviews the characteristics of ferroptosis and the regulatory mechanisms promoting or inhibiting ferroptosis. More importantly, it further discusses the role of ferroptosis in acute leukemia and predicts a change in treatment strategy brought about by increased knowledge of the role of ferroptosis in acute leukemia.

Overexpression of ferroptosis-related genes FSP1 and CISD1 is related to prognosis and tumor immune infiltration in gastric cancer

PURPOSE

Gastric cancer (GC) is one of the highest incidence rate cancers worldwide and the search for new biomarkers remains urgent due to its relatively poor prognosis and limited treatment methods. Ferroptosis suppressor protein 1 (FSP1) and iron sulfur domain 1 (CISD1) promoted malignant tumor progression as ferroptosis suppressors in a variety of tumors, but their study in GC remains to be explored.

METHODS

In our study, FSP1 and CISD1 expression were predicted through different databases and confirmed by qRT-PCR, immunohistochemistry and western blotting. Enrichment analyses were exploited to explore the potential functions of FSP1 and CISD1. Finally, their relationship with immune infiltration was determined by Tumor Immune Estimation Resource and ssGSEA algorithm.

RESULTS

The expression of FSP1 and CISD1 was higher in GC tissues. Their strongly positive immunostaining was associated with increased tumor size, degree of differentiation, depth of invasion and lymph node metastasis in GC patients. Up-regulated FSP1 and CISD1 predicted poorer overall survival of patients with GC. Furthermore, FSP1 and CISD1 as ferroptosis inhibitors were predicted to be involved in GC immune cell infiltration.

CONCLUSIONS

Our study suggested that FSP1 and CISD1 acted as biomarkers of poor prognosis and promising immunotherapeutic targets for GC.

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

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

Ferroptosis, necroptosis and cuproptosis: Novel forms of regulated cell death in diabetic cardiomyopathy

Diabetes is a common chronic metabolic disease, and its incidence continues to increase year after year. Diabetic patients mainly die from various complications, with the most common being diabetic cardiomyopathy. However, the detection rate of diabetic cardiomyopathy is low in clinical practice, and targeted treatment is lacking. Recently, a large number of studies have confirmed that myocardial cell death in diabetic cardiomyopathy involves pyroptosis, apoptosis, necrosis, ferroptosis, necroptosis, cuproptosis, cellular burial, and other processes. Most importantly, numerous animal studies have shown that the onset and progression of diabetic cardiomyopathy can be mitigated by inhibiting these regulatory cell death processes, such as by utilizing inhibitors, chelators, or genetic manipulation. Therefore, we review the role of ferroptosis, necroptosis, and cuproptosis, three novel forms of cell death in diabetic cardiomyopathy, searching for possible targets, and analyzing the corresponding therapeutic approaches to these targets.

Ferroptosis, necroptosis and cuproptosis: Novel forms of regulated cell death in diabetic cardiomyopathy

Diabetes is a common chronic metabolic disease, and its incidence continues to increase year after year. Diabetic patients mainly die from various complications, with the most common being diabetic cardiomyopathy. However, the detection rate of diabetic cardiomyopathy is low in clinical practice, and targeted treatment is lacking. Recently, a large number of studies have confirmed that myocardial cell death in diabetic cardiomyopathy involves pyroptosis, apoptosis, necrosis, ferroptosis, necroptosis, cuproptosis, cellular burial, and other processes. Most importantly, numerous animal studies have shown that the onset and progression of diabetic cardiomyopathy can be mitigated by inhibiting these regulatory cell death processes, such as by utilizing inhibitors, chelators, or genetic manipulation. Therefore, we review the role of ferroptosis, necroptosis, and cuproptosis, three novel forms of cell death in diabetic cardiomyopathy, searching for possible targets, and analyzing the corresponding therapeutic approaches to these targets.

Role of ferroptosis in pregnancy related diseases and its therapeutic potential

Ferroptosis is a form of regulated cell death characterized by iron overload, overwhelming lipid peroxidation, and disruption of antioxidant systems. Emerging evidence suggests that ferroptosis is associated with pregnancy related diseases, such as spontaneous abortion, pre-eclampsia, gestational diabetes mellitus, intrahepatic cholestasis of pregnancy, and spontaneous preterm birth. According to these findings, inhibiting ferroptosis might be a potential option to treat pregnancy related diseases. This review summarizes the mechanisms and advances of ferroptosis, the pathogenic role of ferroptosis in pregnancy related diseases and the potential medicines for its treatment.

A genome-wide CRISPR-Cas9 knockout screen identifies FSP1 as the warfarin-resistant vitamin K reductase

Vitamin K is a vital micronutrient implicated in a variety of human diseases. Warfarin, a vitamin K antagonist, is the most commonly prescribed oral anticoagulant. Patients overdosed on warfarin can be rescued by administering high doses of vitamin K because of the existence of a warfarin-resistant vitamin K reductase. Despite the functional discovery of vitamin K reductase over eight decades ago, its identity remained elusive. Here, we report the identification of warfarin-resistant vitamin K reductase using a genome-wide CRISPR-Cas9 knockout screen with a vitamin K-dependent apoptotic reporter cell line. We find that ferroptosis suppressor protein 1 (FSP1), a ubiquinone oxidoreductase, is the enzyme responsible for vitamin K reduction in a warfarin-resistant manner, consistent with a recent discovery by Mishima et al. FSP1 inhibitor that inhibited ubiquinone reduction and thus triggered cancer cell ferroptosis, displays strong inhibition of vitamin K-dependent carboxylation. Intriguingly, dihydroorotate dehydrogenase, another ubiquinone-associated ferroptosis suppressor protein parallel to the function of FSP1, does not support vitamin K-dependent carboxylation. These findings provide new insights into selectively controlling the physiological and pathological processes involving electron transfers mediated by vitamin K and ubiquinone.

Dynamic Metabolic and Transcriptional Responses of Proteasome-Inhibited Neurons

Proteasome inhibition is associated with parkinsonian pathology in vivo and degeneration of dopaminergic neurons in vitro. We explored here the metabolome (386 metabolites) and transcriptome (3257 transcripts) regulations of human LUHMES neurons, following exposure to MG-132 [100 nM]. This proteasome inhibitor killed cells within 24 h but did not reduce viability for 12 h. Overall, 206 metabolites were changed in live neurons. The early (3 h) metabolome changes suggested a compromised energy metabolism. For instance, AMP, NADH and lactate were up-regulated, while glycolytic and citric acid cycle intermediates were down-regulated. At later time points, glutathione-related metabolites were up-regulated, most likely by an early oxidative stress response and activation of NRF2/ATF4 target genes. The transcriptome pattern confirmed proteostatic stress (fast up-regulation of proteasome subunits) and also suggested the progressive activation of additional stress response pathways. The early ones (e.g., HIF-1, NF-kB, HSF-1) can be considered a cytoprotective cellular counter-regulation, which maintained cell viability. For instance, a very strong up-regulation of AIFM2 (=FSP1) may have prevented fast ferroptotic death. For most of the initial period, a definite life-death decision was not taken, as neurons could be rescued for at least 10 h after the start of proteasome inhibition. Late responses involved p53 activation and catabolic processes such as a loss of pyrimidine synthesis intermediates. We interpret this as a phase of co-occurrence of protective and maladaptive cellular changes. Altogether, this combined metabolomics-transcriptomics analysis informs on responses triggered in neurons by proteasome dysfunction that may be targeted by novel therapeutic intervention in Parkinson's disease.

Ferroptosis-associated circular RNAs: Opportunities and challenges in the diagnosis and treatment of cancer

Ferroptosis is an emerging form of non-apoptotic regulated cell death which is different from cell death mechanisms such as autophagy, apoptosis and necrosis. It is characterized by iron-dependent lipid peroxide accumulation. Circular RNA (circRNA) is a newly studied evolutionarily conserved type of non-coding RNA with a covalent closed-loop structure. It exhibits universality, conservatism, stability and particularity. At present, the functions that have been studied and found include microRNA sponge, protein scaffold, transcription regulation, translation and production of peptides, etc. CircRNA can be used as a biomarker of tumors and is a hotspot in RNA biology research. Studies have shown that ferroptosis can participate in tumor regulation through the circRNA molecular pathway and then affect cancer progression, which may become a direction of cancer diagnosis and treatment in the future. This paper reviews the molecular biological mechanism of ferroptosis and the role of circular RNA in tumors and summarizes the circRNA related to ferroptosis in tumors, which may inspire research prospects for the precise prevention and treatment of cancer in the future.

Role of Ferroptosis in Stroke

Stroke is a common and serious nervous system disease caused by the rupture or blockage of the cardiovascular system. It causes millions of deaths and disabilities every year, which is a huge burden on humanity. It may be induced by thrombosis, hypertension, hyperlipidemia, hyperglycemia, smoking, advanced age and so on. According to different causes, stroke can be generally divided into hemorrhagic stroke and ischemic stroke, whose pathogenesis and treatment are quite different. Ferroptosis is a new type of cell death first defined in 2012, which is characterized by non-apoptotic, iron-dependent, and over-accumulated lipid peroxides. Excess lipid reactive oxygen species produced during ferroptosis eventually leads to oxidative cell death. Ferroptosis has been shown to occur and play an important role in tumors, neurological diseases, kidney injury, and ischemia-reperfusion injury. Ferroptosis is also closely related to the pathogenesis of stroke. Moreover, scientists have successfully intervened in the process of stroke in animal models by regulating ferroptosis, indicating that ferroptosis is a new potential target for the treatment of stroke. This paper systematically summarizes the involvement and role of ferroptosis in the pathogenesis of stroke and predicts the potential of ferroptosis in the treatment of stroke. Ferroptosis in stroke. Stroke induces iron overload and lipid metabolism disorders. Elevated iron catalyzes lipid peroxidation and eventually triggers ferroptosis. Conversely, the GSH/GPX4 pathway, as well as CoQ10, Fer-1, and Lip-1, inhibits lipid peroxidation and, thus, alleviates ferroptosis. GSH glutathione; GPX4 glutathione peroxidase 4; CoQ10 coenzyme Q10; Lip-1 liproxstatin-1; Fer-1 ferostatin-1.

Molecular mechanisms of neuronal death in brain injury after subarachnoid hemorrhage

Subarachnoid haemorrhage (SAH) is a common cerebrovascular disease with high disability and mortality rates worldwide. The pathophysiological mechanisms involved in an aneurysm rupture in SAH are complex and can be divided into early brain injury and delayed brain injury. The initial mechanical insult results in brain tissue and vascular disruption with hemorrhages and neuronal necrosis. Following this, the secondary injury results in diffused cerebral damage in the peri-core area. However, the molecular mechanisms of neuronal death following an aneurysmal SAH are complex and currently unclear. Furthermore, multiple cell death pathways are stimulated during the pathogenesis of brain damage. Notably, particular attention should be devoted to necrosis, apoptosis, autophagy, necroptosis, pyroptosis and ferroptosis. Thus, this review discussed the mechanism of neuronal death and its influence on brain injury after SAH.

Treatment with the Ferroptosis Inhibitor Ferrostatin-1 Attenuates Noise-Induced Hearing Loss by Suppressing Ferroptosis and Apoptosis

Hair cell death induced by excessive reactive oxygen species (ROS) has been identified as the major pathogenesis of noise-induced hearing loss (NIHL). Recent studies have demonstrated that cisplatin- and neomycin-induced ototoxicity can be alleviated by ferroptosis inhibitors. However, whether ferroptosis inhibitors have a protective effect against NIHL remains unknown. We investigated the protective effect of the ferroptosis inhibitor ferrostatin-1 (Fer-1) on NIHL in vivo in CBA/J mice and investigated the protective effect of Fer-1 on tert-butyl hydroperoxide (TBHP)-induced hair cell damage in vitro in cochlear explants and HEI-OC1 cells. We observed ROS overload and lipid peroxidation, which led to outer hair cell (OHC) apoptosis and ferroptosis, in the mouse cochlea after noise exposure. The expression level of apoptosis-inducing factor mitochondria-associated 2 (AIFM2) was substantially increased following elevation of the expression of its upstream protein P53 after noise exposure. The ferroptosis inhibitor Fer-1was demonstrated to enter the inner ear after the systemic administration. Administration of Fer-1 significantly alleviated noise-induced auditory threshold elevation and reduced the loss of OHCs, inner hair cell (IHC) ribbon synapses, and auditory nerve fibers (ANFs) caused by noise. Mechanistically, Fer-1 significantly reduced noise- and TBHP-induced lipid peroxidation and iron accumulation in hair cells, alleviating ferroptosis in cochlear cells consequently. Furthermore, Fer-1 treatment decreased the levels of TfR1, P53, and AIFM2. These results suggest that Fer-1 exerted its protective effects by scavenging of ROS and inhibition of TfR1-mediated ferroptosis and P53-AIFM2 signaling pathway-mediated apoptosis. Our findings suggest that Fer-1 is a promising drug for treating NIHL because of its ability to inhibit noise-induced hair cell apoptosis and ferroptosis, opening new avenues for the treatment of NIHL.

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.

Signaling pathways and defense mechanisms of ferroptosis

As a type of lytic cell death driven by unrestricted lipid peroxidation and subsequent plasma membrane damage, ferroptosis occurs and develops because of sophisticated signals and regulatory mechanisms. The reactive oxygen species (ROS) used to initiate ferroptosis come from a variety of sources, including iron-mediated Fenton reactions, mitochondrial ROS, and membrane-associated ROS driven by the NOX protein family. Polyunsaturated fatty acid-containing phospholipids are the main substrates of lipid peroxidation in ferroptosis, which is positively regulated by enzymes, such as ACSL4, LPCAT3, ALOXs, or POR. Selective activation of autophagic degradation pathways promotes ferroptosis by increasing iron accumulation to cause lipid peroxidation. In contrast, system xc^- -glutathione-GPX4 axis plays a central role in limiting lipid peroxidation, although other antioxidants (such as coenzyme Q10 and tetrahydrobiopterin) can also inhibit ferroptosis. A main nuclear mechanism of cell defense against ferroptosis is the activation of the NFE2L2-dependent antioxidant response by transcriptionally upregulating the expression of antioxidants or cytoprotective genes. Additionally, the membrane damage caused by ferroptotic stimulus can be repaired by ESCRT-III-dependent membrane scission machinery. In this review, we summarize recent progress in understanding the signaling pathways and defense mechanisms of ferroptosis.

Mitochondrion-Mediated Cell Death through Erk1-Alox5 Independent of Caspase-9 Signaling

Mitochondrial disruption leads to the release of cytochrome c to activate caspase-9 and the downstream caspase cascade for the execution of apoptosis. However, cell death can proceed efficiently in the absence of caspase-9 following mitochondrial disruption, suggesting the existence of caspase-9-independent cell death mechanisms. Through a genome-wide siRNA library screening, we identified a network of genes that mediate caspase-9-independent cell death, through ROS production and Alox5-dependent membrane lipid peroxidation. Erk1-dependent phosphorylation of Alox5 is critical for targeting Alox5 to the nuclear membrane to mediate lipid peroxidation, resulting in nuclear translocation of cytolytic molecules to induce DNA damage and cell death. Consistently, double knockouts of caspase-9 and Alox5 in mice, but not deletion of either gene alone, led to significant T cell expansion with inhibited cell death, indicating that caspase-9- and Alox5-dependent pathways function in parallel to regulate T cell death in vivo. This unbiased whole-genome screening reveals an Erk1-Alox5-mediated pathway that promotes membrane lipid peroxidation and nuclear translocation of cytolytic molecules, leading to the execution of cell death in parallel to the caspase-9 signaling cascade.

New perspectives on ferroptosis and its role in hepatocellular carcinoma

ABSTRACT

For a long time, the morbidity and mortality rates of hepatocellular carcinoma (HCC) have remained high. Since the concept of ferroptosis was introduced in 2012, researchers' perspectives have shifted toward finding novel ferroptosis-related treatment strategies, especially for tumors that are resistant to apoptosis. In recent years, there have been an increasing number of studies on ferroptosis, and these studies have found that ferroptosis has great potential and promise for cancer treatment. Ferroptosis is a kind of regulated cell death (RCD); unlike apoptosis, ferroptosis is an iron-dependent type of RCD driven by lipid peroxidation. The whole process of ferroptosis mainly revolves around three pathways (system xc-/ glutathione peroxidase 4 [GPX4]), lipid peroxidation, and iron metabolism), which are also regulated by various metabolic factors. This review will attempt to analyze the relationship between the system xc-/GPX4 pathway, lipid peroxidation, iron metabolism, and ferroptosis from three aspects (triggering, execution, and regulation), and the regulatory factors for ferroptosis will be summarized. In this review, we will also illustrate the relationship between ferroptosis and tumors as well as its application in tumors from the perspective of HCC. Finally, we will summarize the current limitations and needs and provide perspectives related to the focus of development in the future.

Acute lymphoblastic leukemia necessitates GSH-dependent ferroptosis defenses to overcome FSP1-epigenetic silencing

Ferroptosis is a form of cell death triggered by phospholipid hydroperoxides (PLOOH) generated from the iron-dependent oxidation of polyunsaturated fatty acids (PUFAs). To prevent ferroptosis, cells rely on the antioxidant glutathione (GSH), which serves as cofactor of the glutathione peroxidase 4 (GPX4) for the neutralization of PLOOHs. Some cancer cells can also limit ferroptosis through a GSH-independent axis, centered mainly on the ferroptosis suppressor protein 1 (FSP1). The significance of these two anti-ferroptosis pathways is still poorly understood in cancers from hematopoietic origin. Here, we report that blood-derived cancer cells are selectively sensitive to compounds that block the GSH-dependent anti-ferroptosis axis. In T- and B- acute lymphoblastic leukemia (ALL) cell lines and patient biopsies, the promoter of the gene coding for FSP1 is hypermethylated, silencing the expression of FSP1 and creating a selective dependency on GSH-centered anti-ferroptosis defenses. In-trans expression of FSP1 increases the resistance of leukemic cells to compounds targeting the GSH-dependent anti-ferroptosis pathway. FSP1 over-expression also favors ALL-tumor growth in an in vivo chick chorioallantoic membrane (CAM) model. Hence, our results reveal a metabolic vulnerability of ALL that might be of therapeutic interest.

Current progress of ferroptosis study in ovarian cancer

Tumors are the leading cause of death all over the world, among which ovarian cancer ranks the third in gynecological malignancies. The current treatment for ovarian cancer is liable to develop chemotherapy resistance and high recurrence rate, in which a new strategy is demanded. Ferroptosis, a newly discovered manner of regulatory cell death, is shown to be induced by massive iron-dependent accumulation of lipid reactive oxygen species. With the in-depth study of ferroptosis, its associated mechanism with various tumors is gradually elucidated, including ovarian tumor, which probably promotes the application of ferroptosis in treating ovarian cancer. To this end, this review will focus on the history and current research progress of ferroptosis, especially its regulation mechanism, and its potential application as a novel treatment strategy for ovarian cancer.

Targeting ferroptosis in ischemia/reperfusion renal injury

Renal I/R injury is a severe medical condition contributing to acute kidney injury (AKI), leading to rapid kidney dysfunction and high mortality rates. It is generally observed during renal transplantation, shock, trauma, and urologic and cardiovascular surgery, for which there is no effective treatment. Cell death and damage are commonly linked to I/R. Cell death triggered by iron-dependent lipid peroxidation, such as ferroptosis, has been demonstrated to have a significant detrimental effect in renal IRI models, making it a new type of cell death currently being researched. Ferroptosis is a nonapoptotic type of cell death that occurs when free iron enters the cell and is a critical component of many biological processes. In ferroptosis-induced renal I/R injury, iron chelators such as Deferasirox, Deferiprone, and lipophilic antioxidants are currently suppressed lipid peroxidation Liproxstatin-1 (Lip-1), Ferrostatin-1 along with antioxidants like vitamin and quercetin. Ferroptosis has been considered a potential target for pharmaceutical intervention to alleviate renal IRI-associated cell damage. Thus, this review emphasized the role of ferroptosis and its inhibition in renal IRI. Also, Pharmacological modulation of ferroptosis mechanism in renal I/R injury has been conferred. Graphical abstract.

Targeting ferroptosis as a vulnerability in pulmonary diseases

Ferroptosis is an iron-dependent regulated cell death marked by excessive oxidative phospholipids (PLs). The polyunsaturated fatty acids-containing phospholipids (PUFA-PLs) are highly susceptible to lipid peroxidation under oxidative stress. Numerous pulmonary diseases occurrences and degenerative pathologies are driven by ferroptosis. This review discusses the role of ferroptosis in the pathogenesis of pulmonary diseases including asthma, lung injury, lung cancer, fibrotic lung diseases, and pulmonary infection. Additionally, it is proposed that targeting ferroptosis is a potential treatment for pulmonary diseases, particularly drug-resistant lung cancer or antibiotic-resistant pulmonary infection, and reduces treatment-related adverse events.

Ferroptosis and ferritinophagy in diabetes complications

BACKGROUND

With long-term metabolic malfunction, diabetes can cause serious damage to whole-body tissue and organs, resulting in a variety of complications. Therefore, it is particularly important to further explore the pathogenesis of diabetes complications and develop drugs for prevention and treatment. In recent years, different from apoptosis and necrosis, ferroptosis has been recognized as a new regulatory mode of cell death and involves the regulation of nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy. Evidence shows that ferroptosis and ferritinophagy play a significant role in the occurrence and development of diabetes complications.

SCOPE OF REVIEW

we systematically review the current understanding of ferroptosis and ferritinophagy, focusing on their potential mechanisms, connection, and regulation, discuss their involvement in diabetes complications, and consider emerging therapeutic opportunities and the associated challenges with future prospects.

MAJOR CONCLUSIONS

In summary, ferroptosis and ferritinophagy are worthy targets for the treatment of diabetes complications, but their complete molecular mechanism and pathophysiological process still require further study.

Lipid Metabolism and Cancer

Lipid metabolism is involved in the regulation of numerous cellular processes, such as cell growth, proliferation, differentiation, survival, apoptosis, inflammation, movement, membrane homeostasis, chemotherapy response, and drug resistance. Reprogramming of lipid metabolism is a typical feature of malignant tumors. In a variety of cancers, fat uptake, storage and fat production are up-regulated, which in turn promotes the rapid growth, invasion, and migration of tumors. This paper systematically summarizes the key signal transduction pathways and molecules of lipid metabolism regulating tumors, and the role of lipid metabolism in programmed cell death. In conclusion, understanding the potential molecular mechanism of lipid metabolism and the functions of different lipid molecules may facilitate elucidating the mechanisms underlying the occurrence of cancer in order to discover new potential targets for the development of effective antitumor drugs.