NEET Proteins: A New Link Between Iron Metabolism, Reactive Oxygen Species, and Cancer

Unraveling the molecular mechanism underlying the anticancer activity of CISD2/NAF-144-67

We recently reported on the development of a unique cancer-targeting peptide called NAF-144-67 (derived from CISD2/NAF-1). NAF-144-67 selectively permeates the plasma membrane (PM) of cancer cells, but not healthy cells, causing the activation of apoptotic and ferroptotic cell death pathways specifically in cancer cells. NAF-144-67 also targets and shrinks human breast and ovarian cancer tumors in a xenograft mice model system without any apparent side effects. Although the specific permeation of NAF-144-67 through cancer cell PMs was studied, and its cancer killing effects validated in vitro and in vivo, little is known about how NAF-144-67 exerts its biological activity once it enters cancer cells. Here, we report that NAF-144-67 targets the CISD2/NAF-1 protein of cancer cells and disrupts its homodimeric structure. We further reveal that a peptide derived from the same domain of the human CISD1 (mitoNEET; mNT19-42) protein, a close family member to CISD2, has no killing activity towards cancer cells, and that dimers of NAF-144-67 (at two different orientations) have higher anticancer activity compared to monomeric NAF-144-67. Our findings shed new light on the biological activity of NAF-144-67 and bring it closer to becoming a potential new anticancer drug.

Genetic profile of ferroptosis in non-small cell lung carcinoma and pharmaceutical options for ferroptosis induction

Lung cancer (LC) is the leading cause of cancer-related deaths and the second most commonly diagnosed malignancy worldwide. Lung adenocarcinoma (LUAD) and lung squamous cell LC (LUSCC) are the most common subtypes of non-small cell LC (NSCLC). Early diagnosis of LC can be challenging due to a lack of biomarkers. The overall survival (OS) of patients with NSCLC is still poor despite the enormous efforts that have been made to develop novel treatments. Understanding fundamental molecular and genetic mechanisms is necessary to develop new therapeutic approaches for NSCLC. A recently identified type of programmed cell death known as ferroptosis is one potential approach. Ferroptosis causes oxidative damage and the death of cancerous cells by peroxidizing unsaturated phospholipids and accumulating reactive oxygen species (ROS) in an iron-dependent manner. Ferroptosis-related gene (FRG) signatures have recently been evaluated for their ability to predict patient OS and prognosis. These analyses show FRGs are involved in cancer progression, and may serve as promising biomarkers for tumor diagnosis and therapy. Moreover, we summarize the current pharmaceutical options of ferroptosis induction and their underlying molecular mechanism in LC. Therefore, this review aims to provide a comprehensive summary of FRG-based prognostic models, their associated metabolic and signaling pathways, and promising therapeutic options for ferroptosis induction in NSCLC.

Ferroptosis: A Mechanism of Cell Death With Potential Scope in Cancer Therapy

Ferroptosis is a type of regulated cell death caused by oxidative imbalance of the intracellular microenvironment. This causes the accumulation of toxic lipid peroxides, depicted by iron overload and lipid peroxidation, which results in disease development. The affected cell population displays unique morphological and biochemical features, which are distinct from other modes of cell death, like apoptosis, pyroptosis, and necroptosis. The individual pathways of each of these modes are interrelated and tend to counterbalance each other in the mechanism of cell death. The process of ferroptosis is associated with disturbances in iron metabolism, in conjunction with glutathione peroxidase and lipid peroxidation, culminating in a reduction of antioxidant capacity and accumulation of lipid peroxides in the dying cell. It has been observed that even excess cellular levels of iron can cause cell death, where ferroptosis is initiated by diminishing the levels of glutathione and glutathione peroxidase 4, and thus leading to excess build-up of lipid reactive oxygen species (ROS). In the case of a neoplastic cell, ferroptosis along with its regulators tends to orchestrate cell death and also affects cancer progression by modulation of proliferation activity, apoptosis suppression, metastasis, and drug resistance. Comprehending the complex network of molecular processes implicated in ferroptosis regulation is vital for developing targeted therapies for diseases where ferroptosis plays a significant role.

Ferroptosis in immune chaos: Unraveling its impact on disease and therapeutic potential

Since its introduction in 2012, ferroptosis has garnered significant attention from researchers over the past decade. Unlike autophagy and apoptosis, ferroptosis is an atypical iron-dependent programmed cell death that falls under necrosis. It is regulated by various cellular metabolic and signaling processes, which encompass amino acid, lipid, iron, and mitochondrial metabolism. The initiation of ferroptosis occurs through iron-dependent phospholipid peroxidation. Notably, ferroptosis exhibits a dual effect and is associated with various diseases. A significant challenge lies in managing autoimmune disorders with unknown origins that stem from the reactivation of the immune system. Two contributing factors to autoimmunity are the aberrant stimulation of cell death and the inadequate clearance of dead cells, which can expose or release intracellular components that activate the immune response. Ferroptosis is distinct from other forms of cell death, such as apoptosis, necroptosis, autophagy, and pyroptosis, due to its unique morphological, biochemical, and genetic characteristics and specific relationship with cellular iron levels. Recent studies indicate that immune cells can both induce and undergo ferroptosis. To better understand how ferroptosis influences immune responses and its imbalance in disease, a molecular understanding of the relationship between ferroptosis and immunity is essential. Consequently, further research is needed to develop immunotherapeutics that target ferroptosis. This review primarily focuses on the role of ferroptosis in immune-related disorders.

Unraveling the molecular mechanism underlying the anticancer activity of CISD2/NAF-1 44-67

We recently reported on the development of a unique cancer-targeting peptide called NAF-1 44-67 (derived from CISD2/NAF-1). NAF-1 44-67 selectively permeates the plasma membrane (PM) of cancer cells, but not healthy cells, causing the activation of apoptotic and ferroptotic cell death pathways specifically in cancer cells. NAF-1 44-67 also targets and shrinks human breast and ovarian cancer tumors in a xenograft mice model system without any apparent side effects. Although the specific permeation of NAF-1 44-67 through cancer cell PMs was studied, and its cancer killing effects validated in vitro and in vivo , little is known about how NAF-1 44-67 exerts its biological activity once it enters cancer cells. Here, we report that NAF-1 44-67 targets the CISD2/NAF-1 protein of cancer cells and disrupts its homodimeric structure. We further reveal that a peptide derived from the same domain of the human CISD1 (mitoNEET; mNT 19-42 ) protein, a close family member to CISD2, has no killing activity towards cancer cells, and that dimers of NAF-1 44-67 (at two different orientations) have higher anticancer activity compared to monomeric NAF-1 44-67 . Our findings shed new light on the biological activity of NAF-1 44-67 and bring it closer to becoming a potential new anticancer drug.

CISD2-mediated mitochondrial dysfunction and iron redistribution contributes to ferroptosis in arsenic-induced nonalcoholic steatohepatitis

Arsenic in the environment, such as sodium arsenic (NaAsO2), is a frequently occurring hazard that has been linked to nonalcoholic steatohepatitis (NASH). Our prior research established the involvement of ferroptosis in arsenic-induced NASH, but the precise underlying mechanisms remain elusive. Here, we found that exposure to NaAsO2 had a suppressive effect on the expression of CDGSH iron-sulfur domain-containing protein 2 (CISD2) at the protein and gene levels, and overexpression of CISD2 inhibited NaAsO2-induced ferroptosis and NASH. Additionally, administration of NaAsO2 to hepatocytes triggered mitochondrial dysfunction, manifesting as the release of cytochrome c, impairment of the mitochondrial respiratory chain, and reduction in ATP synthesis. However, these adverse effects were alleviated through overexpression of CISD2. Intracellular iron redistribution was induced by overexpression of CISD2 and inhibited NaAsO2-induced ferroptosis. This inhibition was characterized by a reduction in cytoplasmic iron levels and an increase in mitochondrial iron levels. Our study demonstrated that NaAsO2 induced intracellular iron reorganization and mitochondrial dysfunction through CISD2 inhibition, leading to ferroptosis and NASH. This may provide a novel means of treatment of nonalcoholic fatty liver disease triggered by environmental factors.

Nicotine aggravates high-fat diet-induced non-alcoholic fatty liver disease in mice via inhibition of CISD3

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease globally. Growing data suggests that smoking plays an important role in the evolution of NAFLD. CDGSH iron sulfur domain 3 (CISD3) regulates critical biological activities. However, its role in nicotine-associated NAFLD and its underlying mechanisms have not been elucidated. Mice were given a high-fat diet for 10 weeks to induce the development of NAFLD. The results revealed that in mice with NAFLD, nicotine treatment resulted in reduced CISD3 expression, leading to mitochondrial dysfunction and impaired β-oxidation. Notably, exacerbation of hepatic steatosis and inflammatory injury was observed. Furthermore, Cisd3-knockout exacerbated lipid accumulation, aggravating oxidative stress and apoptosis. In conclusion, these results contribute to our knowledge of the function of CISD3 in nicotine-associated NAFLD, revealing the possibility of using CISD3 as a potential molecular target for treating NAFLD.

CISD2 regulates oxidative stress and mitophagy to maintain the balance of the follicular microenvironment in PCOS

OBJECTIVES

To observe the CISD2 expression among PCOS patients and to explore its profound impact on the follicular microenvironment. Moreover, we want to elucidate the intricate mechanistic contribution of CISD2 to the onset and progression of PCOS.

METHODS

Oxidase NOX2, mitophagy-related proteins, and CISD2 were detected by WB. The changes in mitochondrial structure and quantity were observed by transmission electron microscopy. Mitochondrial and lysosome colocalization was used to detect the changes of mitophagy. MDA kit, GSH and GSSG Assay kit and ROS probe were used to detect oxidative stress damage.

RESULTS

We found that CISD2, mitophagy and oxidase in the GCs of PCOS patients were significantly increased. Testosterone stimulation leads to the increase of oxidase, mitophagy, and CISD2 in KGN cells. CISD2 inhibition promoted the increase of mitophagy, and the activation of mitochondria-lysosome binding, while alleviating the oxidative stress.

CONCLUSIONS

Inhibition of CISD2 can improve the occurrence of oxidative stress by increasing the level of mitophagy, thus affecting the occurrence and development of PCOS diseases.

Long-read Ribo-STAMP simultaneously measures transcription and translation with isoform resolution

Transcription and translation are intertwined processes in which mRNA isoforms are crucial intermediaries. However, methodological limitations in analyzing translation at the mRNA isoform level have left gaps in our understanding of critical biological processes. To address these gaps, we developed an integrated computational and experimental framework called long-read Ribo-STAMP (LR-Ribo-STAMP) that capitalizes on advancements in long-read sequencing and RNA-base editing-mediated technologies to simultaneously profile translation and transcription at both the gene and mRNA isoform levels. We also developed the EditsC metric to quantify editing and leverage the single-molecule, full-length transcript information provided by long-read sequencing. Here, we report concordance between gene-level translation profiles obtained with long-read and short-read Ribo-STAMP. We show that LR-Ribo-STAMP successfully profiles translation of mRNA isoforms and links regulatory features, such as upstream open reading frames (uORFs), to translation measurements. We apply LR-Ribo-STAMP to discovering translational differences at both the gene and isoform levels in a triple-negative breast cancer cell line under normoxia and hypoxia and find that LR-Ribo-STAMP effectively delineates orthogonal transcriptional and translation shifts between conditions. We also discover regulatory elements that distinguish translational differences at the isoform level. We highlight GRK6, in which hypoxia is observed to increase expression and translation of a shorter mRNA isoform, giving rise to a truncated protein without the AGC Kinase domain. Overall, LR-Ribo-STAMP is an important advance in our repertoire of methods that measures mRNA translation with isoform sensitivity.

TMSB4X is a regulator of inflammation-associated ferroptosis, and promotes the proliferation, migration and invasion of hepatocellular carcinoma cells

BACKGROUND

Ferroptosis and inflammation are involved in cancer progression. The aim of this study was to identify inflammation-associated ferroptosis regulators in hepatocellular carcinoma (HCC).

METHODS

FerrDb database was searched for ferroptosis-related genes. RNA sequencing data and clinicopathologic information of HCC patients were downloaded from the Cancer Genome Atlas (TCGA) database. Weighted gene co-expression network analysis was applied to obtain the genes probably involved in inflammation-associated ferroptosis. Univariate Cox regression analysis was conducted to screen prognostic genes, and 10 machine learning algorithms were combined to find the optimal strategy to evaluate the prognosis of the patients based on the prognosis-related genes. The patients were divided into high risk group and low risk group, and the differentially expressed genes were obtained. Thymosin beta 4 X-linked (TMSB4X) was overexpressed or knocked down in HCC cell lines, and then qPCR, CCK-8, Transwell, flow cytometery assays were performed to detect the change of HCC cells' phenotypes, and Western blot was used to detect the change of ferroptosis markers.

RESULTS

157 genes related to inflammation and ferroptosis in HCC were obtained by WGCNA. rLasso algorithm, with the highest C-index, screened out 29 hub genes, and this model showed good efficacy to predict the prognosis of HCC patients. The patients in high risk group and low risk groups showed distinct molecular characteristics. TMSB4X was the most important gene which dominated the classification, and it was highly expressed in HCC samples. TMSB4X promoted the viability, migration and invasion, and repressed ferroptosis of HCC cells.

CONCLUSION

The risk model constructed based on the inflammation-associated ferroptosis regulators is effective to predict the clinical outcome of HCC patients. TMSB4X, involved in inflammation-associated ferroptosis, is a potential biomarker and therapeutic target for HCC.

Inhibition of CISD2 enhances sensitivity to doxorubicin in diffuse large B-cell lymphoma by regulating ferroptosis and ferritinophagy

Background

CDGSH iron-sulfur domain 2 (CISD2), an iron-sulfur protein with a [2Fe-2S] cluster, plays a pivotal role in the progression of various cancers, including Diffuse Large B-cell Lymphoma (DLBCL). However, the mechanisms by which CISD2 regulates the occurrence and development of DLBCL remain to be fully elucidated.

Methods

The potential role of CISD2 as a predictive marker in DLBCL patients treated with the R-CHOP regimen was investigated through bioinformatics analysis and clinical cohort studies. DLBCL cell lines (SUDHL-4 and HBL-1) were employed in this research. Adenoviral (AV) plasmids were used to either silence or overexpress CISD2 in these DLBCL cell lines. Additionally, the induction of ferroptosis in DLBCL cell lines was assessed. Various parameters, including cell proliferation, intracellular free iron levels, lipid peroxides, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP), were measured. Furthermore, the expression of proteins associated with ferroptosis and ferritinophagy was analyzed. Drug-resistant DLBCL cell lines were developed by gradually increasing doxorubicin (DOX) concentration over 6 months. The biological role of CISD2 in these drug-resistant DLBCL cell lines was subsequently assessed.

Results

Elevated CISD2 levels were found to be associated with decreased sensitivity of DLBCL patients to the R-CHOP regimen, as indicated by bioinformatics and clinical cohort analysis. Silencing CISD2 significantly reduced cell proliferation, increased iron accumulation, depleted glutathione (GSH), and elevated malondialdehyde (MDA) levels, alongside the accumulation of ROS and increased MMP. Additionally, BECN1 and NCOA4 expressions were upregulated, while p62, FTH1, and GPX4 expressions were downregulated. Conversely, overexpression of CISD2 reversed these effects. Treatment of DLBCL cell lines with Erastin led to decreased CISD2 levels. Notably, in drug-resistant DLBCL cell lines, CISD2 knockdown promoted ferroptosis and ferritinophagy, restoring sensitivity to DOX and enhancing the efficacy of Erastin treatment.

Conclusion

Our findings suggest that CISD2 may play a role in the drug resistance observed in DLBCL patients. Inhibition of CISD2 could enhance ferroptosis and ferritinophagy, potentially improving the sensitivity of DLBCL cells to DOX treatment.

Fighting ischemia-reperfusion injury: Focusing on mitochondria-derived ferroptosis

Ischemia-reperfusion injury (IRI) is a major cause of mortality and morbidity. Current treatments for IRI have limited efficacy and novel therapeutic strategies are needed. Mitochondrial dysfunction not only initiates IRI but also plays a significant role in ferroptosis pathogenesis. Recent studies have highlighted that targeting mitochondrial pathways is a promising therapeutic approach for ferroptosis-induced IRI. The association between ferroptosis and IRI has been reviewed many times, but our review provides the first comprehensive overview with a focus on recent mitochondrial research. First, we present the role of mitochondria in ferroptosis. Then, we summarize the evidence on mitochondrial manipulation of ferroptosis in IRI and review recent therapeutic strategies aimed at targeting mitochondria-related ferroptosis to mitigate IRI. We hope our review will provide new ideas for the treatment of IRI and accelerate the transition from bench to bedside.

CISD3 is a prognostic biomarker and therapeutic target in pan-cancer

Recent studies indicate that CISD3 is crucial in mitochondrial function and tumorigenesis. Using various databases, we systematically analyzed its expression, prognostic value, and immune activity. Our findings show CISD3 is mainly expressed in tumor cells across cancers, with higher mRNA but lower protein levels, degraded post-translationally via the lysosomal pathway. In certain cancers, CISD3 expression is positively correlated with tumor-infiltrating immune cells. Prognostic analysis suggests dual roles as both protective and risk factors, notably an independent prognostic predictor in renal cell carcinoma (RCC). CISD3 copy number variations are linked to homologous recombination defects and tumor-specific neoantigens, negatively correlated with methylation levels. Pathway analysis reveals CISD3 involvement in oncogenic processes, such as proliferation inhibition and epithelial-mesenchymal transition. Protein interactions underline its role in mitochondrial metabolism and redox balance. Experiments confirm low CISD3 expression in cancers, with overexpression reducing proliferation, migration, invasion, and tumor growth in mice. Mechanistic studies indicate CISD3 overexpression disrupts mitochondrial function, increases ROS levels, decreases GSH/GSSG ratios and mitochondrial membrane potential, inhibiting antioxidant activity and promoting cell damage and ferroptosis, thus impeding cancer progression. This study highlights CISD3's potential as a prognostic biomarker and therapeutic target.

Potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in individuals with diabetes

Diabetes and its complications are major diseases that affect human health. Diabetic cardiovascular complications such as cardiovascular diseases (CVDs) are the major complications of diabetes, which are associated with the loss of cardiovascular cells. Pathogenically the role of ferroptosis, an iron-dependent cell death, and cuproptosis, a copper-dependent cell death has recently been receiving attention for the pathogenesis of diabetes and its cardiovascular complications. How exposure to environmental metals affects these two metal-dependent cell deaths in cardiovascular pathogenesis under diabetic and nondiabetic conditions remains largely unknown. As an omnipresent environmental metal, cadmium exposure can cause oxidative stress in the diabetic cardiomyocytes, leading to iron accumulation, glutathione depletion, lipid peroxidation, and finally exacerbate ferroptosis and disrupt the cardiac. Moreover, cadmium-induced hyperglycemia can enhance the circulation of advanced glycation end products (AGEs). Excessive AGEs in diabetes promote the upregulation of copper importer solute carrier family 31 member 1 through activating transcription factor 3/transcription factor PU.1, thereby increasing intracellular Cu+ accumulation in cardiomyocytes and disturbing Cu+ homeostasis, leading to a decline of Fe-S cluster protein and reactive oxygen species accumulation in cardiomyocytes mitochondria. In this review, we summarize the available evidence and the most recent advances exploring the underlying mechanisms of ferroptosis and cuproptosis in CVDs and diabetic cardiovascular complications, to provide critical perspectives on the potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in diabetic individuals.

ATM1, an essential conserved transporter in Apicomplexa, bridges mitochondrial and cytosolic [Fe-S] biogenesis

The Apicomplexa phylum encompasses numerous obligate intracellular parasites, some associated with severe implications for human health, including Plasmodium, Cryptosporidium, and Toxoplasma gondii. The iron-sulfur cluster [Fe-S] biogenesis ISC pathway, localized within the mitochondrion or mitosome of these parasites, is vital for parasite survival and development. Previous work on T. gondii and Plasmodium falciparum provided insights into the mechanisms of [Fe-S] biogenesis within this phylum, while the transporter linking mitochondria-generated [Fe-S] with the cytosolic [Fe-S] assembly (CIA) pathway remained elusive. This critical step is catalyzed by a well-conserved ABC transporter, termed ATM1 in yeast, ATM3 in plants and ABCB7 in mammals. Here, we identify and characterize this transporter in two clinically relevant Apicomplexa. We demonstrate that depletion of TgATM1 does not specifically impair mitochondrial metabolism. Instead, proteomic analyses reveal that TgATM1 expression levels inversely correlate with the abundance of proteins that participate in the transfer of [Fe-S] to cytosolic proteins at the outer mitochondrial membrane. Further insights into the role of TgATM1 are gained through functional complementation with the well-characterized yeast homolog. Biochemical characterization of PfATM1 confirms its role as a functional ABC transporter, modulated by oxidized glutathione (GSSG) and [4Fe-4S].

Dystroglycan-HSPG interactions provide synaptic plasticity and specificity

AIM

This study examined the roles of the laminin and proteoglycan receptor dystroglycan (DG) in extracellular matrix stabilization and cellular mechanosensory processes conveyed through communication between the extracellular matrix (ECM) and cytoskeleton facilitated by DG. Specific functional attributes of HS-proteoglycans (HSPGs) are conveyed through interactions with DG and provide synaptic specificity through diverse interactions with an extensive range of cell attachment and adaptor proteins which convey synaptic plasticity. HSPG-DG interactions are important in phototransduction and neurotransduction and facilitate retinal bipolar-photoreceptor neuronal signaling in vision. Besides synaptic stabilization, HSPG-DG interactions also stabilize basement membranes and the ECM and have specific roles in the assembly and function of the neuromuscular junction. This provides neuromuscular control of muscle systems that control conscious body movement as well as essential autonomic control of diaphragm, intercostal and abdominal muscles and muscle systems in the face, mouth and pharynx which assist in breathing processes. DG is thus a multifunctional cell regulatory glycoprotein receptor and regulates a diverse range of biological and physiological processes throughout the human body. The unique glycosylation of the αDG domain is responsible for its diverse interactions with ECM components in cell-ECM signaling. Cytoskeletal cell regulatory switches assembled by the βDG domain in its role as a nuclear scaffolding protein respond to such ECM cues to regulate cellular behavior and tissue homeostasis thus DG has fascinating and diverse roles in health and disease.

Iron-sulfur cluster loss in mitochondrial CISD1 mediates PINK1 loss-of-function phenotypes

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra of the midbrain. Familial cases of PD are often caused by mutations of PTEN-induced kinase 1 (PINK1) and the ubiquitin ligase Parkin, both pivotal in maintaining mitochondrial quality control. CISD1, a homodimeric mitochondrial iron-sulfur-binding protein, is a major target of Parkin-mediated ubiquitination. We here discovered a heightened propensity of CISD1 to form dimers in Pink1 mutant flies and in dopaminergic neurons from PINK1 mutation patients. The dimer consists of two monomers that are covalently linked by a disulfide bridge. In this conformation CISD1 cannot coordinate the iron-sulfur cofactor. Overexpressing Cisd, the Drosophila ortholog of CISD1, and a mutant Cisd incapable of binding the iron-sulfur cluster in Drosophila reduced climbing ability and lifespan. This was more pronounced with mutant Cisd and aggravated in Pink1 mutant flies. Complete loss of Cisd, in contrast, rescued all detrimental effects of Pink1 mutation on climbing ability, wing posture, dopamine levels, lifespan, and mitochondrial ultrastructure. Our results suggest that Cisd, probably iron-depleted Cisd, operates downstream of Pink1 shedding light on PD pathophysiology and implicating CISD1 as a potential therapeutic target.

Oxidative Metabolism as a Cause of Lipid Peroxidation in the Execution of Ferroptosis

Ferroptosis is a type of nonapoptotic cell death that is characteristically caused by phospholipid peroxidation promoted by radical reactions involving iron. Researchers have identified many of the protein factors that are encoded by genes that promote ferroptosis. Glutathione peroxidase 4 (GPX4) is a key enzyme that protects phospholipids from peroxidation and suppresses ferroptosis in a glutathione-dependent manner. Thus, the dysregulation of genes involved in cysteine and/or glutathione metabolism is closely associated with ferroptosis. From the perspective of cell dynamics, actively proliferating cells are more prone to ferroptosis than quiescent cells, which suggests that radical species generated during oxygen-involved metabolism are responsible for lipid peroxidation. Herein, we discuss the initial events involved in ferroptosis that dominantly occur in the process of energy metabolism, in association with cysteine deficiency. Accordingly, dysregulation of the tricarboxylic acid cycle coupled with the respiratory chain in mitochondria are the main subjects here, and this suggests that mitochondria are the likely source of both radical electrons and free iron. Since not only carbohydrates, but also amino acids, especially glutamate, are major substrates for central metabolism, dealing with nitrogen derived from amino groups also contributes to lipid peroxidation and is a subject of this discussion.

A critical appraisal of ferroptosis in Alzheimer's and Parkinson's disease: new insights into emerging mechanisms and therapeutic targets

Neurodegenerative diseases represent a pressing global health challenge, and the identification of novel mechanisms underlying their pathogenesis is of utmost importance. Ferroptosis, a non-apoptotic form of regulated cell death characterized by iron-dependent lipid peroxidation, has emerged as a pivotal player in the pathogenesis of neurodegenerative diseases. This review delves into the discovery of ferroptosis, the critical players involved, and their intricate role in the underlying mechanisms of neurodegeneration, with an emphasis on Alzheimer's and Parkinson's diseases. We critically appraise unsolved mechanistic links involved in the initiation and propagation of ferroptosis, such as a signaling cascade resulting in the de-repression of lipoxygenase translation and the role played by mitochondrial voltage-dependent anionic channels in iron homeostasis. Particular attention is given to the dual role of heme oxygenase in ferroptosis, which may be linked to the non-specific activity of P450 reductase in the endoplasmic reticulum. Despite the limited knowledge of ferroptosis initiation and progression in neurodegeneration, Nrf2/Bach1 target genes have emerged as crucial defenders in anti-ferroptotic pathways. The activation of Nrf2 and the inhibition of Bach1 can counteract ferroptosis and present a promising avenue for future therapeutic interventions targeting ferroptosis in neurodegenerative diseases.

CISD3/MiNT is required for complex I function, mitochondrial integrity, and skeletal muscle maintenance

Mitochondria play a central role in muscle metabolism and function. A unique family of iron-sulfur proteins, termed CDGSH Iron Sulfur Domain-containing (CISD/NEET) proteins, support mitochondrial function in skeletal muscles. The abundance of these proteins declines during aging leading to muscle degeneration. Although the function of the outer mitochondrial CISD/NEET proteins, CISD1/mitoNEET and CISD2/NAF-1, has been defined in skeletal muscle cells, the role of the inner mitochondrial CISD protein, CISD3/MiNT, is currently unknown. Here, we show that CISD3 deficiency in mice results in muscle atrophy that shares proteomic features with Duchenne muscular dystrophy. We further reveal that CISD3 deficiency impairs the function and structure of skeletal muscles, as well as their mitochondria, and that CISD3 interacts with, and donates its [2Fe-2S] clusters to, complex I respiratory chain subunit NADH Ubiquinone Oxidoreductase Core Subunit V2 (NDUFV2). Using coevolutionary and structural computational tools, we model a CISD3-NDUFV2 complex with proximal coevolving residue interactions conducive of [2Fe-2S] cluster transfer reactions, placing the clusters of the two proteins 10 to 16 Å apart. Taken together, our findings reveal that CISD3/MiNT is important for supporting the biogenesis and function of complex I, essential for muscle maintenance and function. Interventions that target CISD3 could therefore impact different muscle degeneration syndromes, aging, and related conditions.

Exploring Ferroptosis-Associated Gene Signatures as Diagnostic and Therapeutic Targets for Sepsis-Induced Cardiomyopathy

BACKGROUND

Sepsis-induced cardiomyopathy (SICM) is a severe complication of sepsis associated with high mortality rates. Despite its significance, the molecular mechanisms underlying SICM remain poorly understood, particularly the role of ferroptosis - a form of iron-dependent programmed cell death.

METHODOLOGY

This study analyzed the GSE79962 dataset from the Gene Expression Omnibus, containing cardiac gene expression profiles from SICM patients and controls. A list of ferroptosis-related genes (FRGs) was retrieved from the FerrDb. We used the limma package in R for differential expression analysis, setting an adjusted P-value cutoff of <0.05 and a log2-fold change threshold of ±1 to identify differentially expressed ferroptosis-related genes (DE-FRGs). We applied machine learning algorithms for biomarker identification, including least absolute shrinkage and selection operator (LASSO) logistic regression and support vector machine with recursive feature elimination (SVM-RFE), implemented via the glmnet and e1071 packages in R, respectively. Gene set enrichment analysis (GSEA) was conducted using the GSEA package to investigate the biological pathways related to key DE-FRGs.

RESULTS

After differential expression analysis, we identified 145 DE-FRGs. Functional enrichment analyses underscored the involvement of these genes in critical biological processes and pathways, such as lipid metabolism and insulin resistance. Machine learning approaches pinpointed five key DE-FRGs (NCOA4, GABARAPL1, GJA1, CISD1, CP), with strong predictive potential for SICM. Further analyses, including the construction of a ceRNA network, revealed intricate post-transcriptional regulatory mechanisms that may influence the expression of these key genes.

CONCLUSIONS

Our findings highlight the central role of ferroptosis in SICM and identify potential biomarkers and therapeutic targets that could help refine diagnostic and treatment strategies. This study advances our understanding of the molecular underpinnings of SICM and sets the stage for future research aimed at mitigating this severe sepsis complication.

Mitochondria-mediated Ferroptosis in Diseases Therapy: From Molecular Mechanisms to Implications

Ferroptosis, a type of cell death involving iron and lipid peroxidation, has been found to be closely associated with the development of many diseases. Mitochondria are vital components of eukaryotic cells, serving important functions in energy production, cellular metabolism, and apoptosis regulation. Presently, the precise relationship between mitochondria and ferroptosis remains unclear. In this study, we aim to systematically elucidate the mechanisms via which mitochondria regulate ferroptosis from multiple perspectives to provide novel insights into mitochondrial functions in ferroptosis. Additionally, we present a comprehensive overview of how mitochondria contribute to ferroptosis in different conditions, including cancer, cardiovascular disease, inflammatory disease, mitochondrial DNA depletion syndrome, and novel coronavirus pneumonia. Gaining a comprehensive understanding of the involvement of mitochondria in ferroptosis could lead to more effective approaches for both basic cell biology studies and medical treatments.

Inhibition of CISD1 alleviates mitochondrial dysfunction and ferroptosis in mice with acute lung injury

The NET family member, CDGSH iron-sulfur domain-containing protein 1 (CISD1), is located in theoutermembrane of mitochondria, where it regulates energy and iron metabolism. CISD1 has vital functions in certain human diseases; however, its function in acute lung injury (ALI) is unknown. ALI pathogenesis critically involves mitochondrial dysfunction and ferroptosis, which might be regulated by CISD1. Therefore, we investigated CISD1's function in mitochondrial dysfunction and ferroptosis regulation in lipopolysaccharide (LPS)-induced ALI. We found that CISD1 was upregulated in LPS-induced ALI,and silencing Cisd1 prevented cell apoptosis and increased cell viability. When CISD1was inhibited by mitoNEET ligand-1 (NL-1) there was a significant mitigation of pathological injury and lung edema, and reduced numbers of total cells, polymorphonuclear leukocytes, and a decreased protein content in the bronchoalveolar lavage fluid (BALF). Moreover, inhibition of CISD1 markedly decreased the interleukin (IL)6, IL-1β, and tumor necrosis factor alpha (TNF-α) levels in the lungs and BALF of ALI-model mice. Silencing of Cisd1 prevented LPS-induced mitochondrial membrane potential depolarization, cellular ATP reduction, and reactive oxygen species (ROS) accumulation, suggesting mitochondrial protection. ALI activated ferroptosis, as evidenced by the increased lipid-ROS, intracellular Fe2+ level, reduced Gpx4 (glutathione peroxidase 4) expression, and the glutathione/glutathione disulfide ratio. Interestingly, inhibition of CISD1 reduced LPS-induced ferroptosis in vivo and in vitro. In conclusion, inhibition of CISD1 alleviated mitochondrial dysfunction and ferroptosis in LPS-induced ALI, identifying CISD1 as possible target for therapy of LPS-induced ALI.

Biochemical and cellular characterization of the CISD3 protein: Molecular bases of cluster release and destabilizing effects of nitric oxide

The NEET proteins, an important family of iron-sulfur (Fe-S) proteins, have generated a strong interest due to their involvement in diverse diseases such as cancer, diabetes, and neurodegenerative disorders. Among the human NEET proteins, CISD3 has been the least studied, and its functional role is still largely unknown. We have investigated the biochemical features of CISD3 at the atomic and in cellulo levels upon challenge with different stress conditions i.e., iron deficiency, exposure to hydrogen peroxide, and nitric oxide. The redox and cellular stability properties of the protein agree on a predominance of reduced form of CISD3 in the cells. Upon the addition of iron chelators, CISD3 loses its Fe-S clusters and becomes unstructured, and its cellular level drastically decreases. Chemical shift perturbation measurements suggest that, upon cluster oxidation, the protein undergoes a conformational change at the C-terminal CDGSH domain, which determines the instability of the oxidized state. This redox-associated conformational change may be the source of cooperative electron transfer via the two [Fe2S2] clusters in CISD3, which displays a single sharp voltammetric signal at -31 mV versus SHE. Oxidized CISD3 is particularly sensitive to the presence of hydrogen peroxide in vitro, whereas only the reduced form is able to bind nitric oxide. Paramagnetic NMR provides clear evidence that, upon NO binding, the cluster is disassembled but iron ions are still bound to the protein. Accordingly, in cellulo CISD3 is unaffected by oxidative stress induced by hydrogen peroxide but it becomes highly unstable in response to nitric oxide treatment.

The effects of multifactorial stress combination on rice and maize

The complexity of environmental factors affecting crops in the field is gradually increasing due to climate change-associated weather events, such as droughts or floods combined with heat waves, coupled with the accumulation of different environmental and agricultural pollutants. The impact of multiple stress conditions on plants was recently termed "multifactorial stress combination" (MFSC) and defined as the occurrence of 3 or more stressors that impact plants simultaneously or sequentially. We recently reported that with the increased number and complexity of different MFSC stressors, the growth and survival of Arabidopsis (Arabidopsis thaliana) seedlings declines, even if the level of each individual stress is low enough to have no significant effect on plants. However, whether MFSC would impact commercial crop cultivars is largely unknown. Here, we reveal that a MFSC of 5 different low-level abiotic stresses (salinity, heat, the herbicide paraquat, phosphorus deficiency, and the heavy metal cadmium), applied in an increasing level of complexity, has a significant negative impact on the growth and biomass of a commercial rice (Oryza sativa) cultivar and a maize (Zea mays) hybrid. Proteomics, element content, and mixOmics analyses of MFSC in rice identified proteins that correlate with the impact of MFSC on rice seedlings, and analysis of 42 different rice genotypes subjected to MFSC revealed substantial genetic variability in responses to this unique state of stress combination. Taken together, our findings reveal that the impacts of MFSC on 2 different crop species are severe and that MFSC may substantially affect agricultural productivity.

Antioxidant Systems as Modulators of Ferroptosis: Focus on Transcription Factors

Ferroptosis is a type of programmed cell death that differs from apoptosis, autophagy, and necrosis and is related to several physio-pathological processes, including tumorigenesis, neurodegeneration, senescence, blood diseases, kidney disorders, and ischemia-reperfusion injuries. Ferroptosis is linked to iron accumulation, eliciting dysfunction of antioxidant systems, which favor the production of lipid peroxides, cell membrane damage, and ultimately, cell death. Thus, signaling pathways evoking ferroptosis are strongly associated with those protecting cells against iron excess and/or lipid-derived ROS. Here, we discuss the interaction between the metabolic pathways of ferroptosis and antioxidant systems, with a particular focus on transcription factors implicated in the regulation of ferroptosis, either as triggers of lipid peroxidation or as ferroptosis antioxidant defense pathways.

Dysregulated iron homeostasis in dystrophin-deficient cardiomyocytes: correction by gene editing and pharmacological treatment

AIMS

Duchenne muscular dystrophy (DMD)-associated cardiomyopathy is a serious life-threatening complication, the mechanisms of which have not been fully established, and therefore no effective treatment is currently available. The purpose of the study was to identify new molecular signatures of the cardiomyopathy development in DMD.

METHODS AND RESULTS

For modelling of DMD-associated cardiomyopathy, we prepared three pairs of isogenic control and dystrophin-deficient human induced pluripotent stem cell (hiPSC) lines. Two isogenic hiPSC lines were obtained by CRISPR/Cas9-mediated deletion of DMD exon 50 in unaffected cells generated from healthy donor and then differentiated into cardiomyocytes (hiPSC-CM). The latter were subjected to global transcriptomic and proteomic analyses followed by more in-depth investigation of selected pathway and pharmacological modulation of observed defects. Proteomic analysis indicated a decrease in the level of mitoNEET protein in dystrophin-deficient hiPSC-CM, suggesting alteration in iron metabolism. Further experiments demonstrated increased labile iron pool both in the cytoplasm and mitochondria, a decrease in ferroportin level and an increase in both ferritin and transferrin receptor in DMD hiPSC-CM. Importantly, CRISPR/Cas9-mediated correction of the mutation in the patient-derived hiPSC reversed the observed changes in iron metabolism and restored normal iron levels in cardiomyocytes. Moreover, treatment of DMD hiPSC-CM with deferoxamine (DFO, iron chelator) or pioglitazone (mitoNEET stabilizing compound) decreased the level of reactive oxygen species in DMD hiPSC-CM.

CONCLUSION

To our knowledge, this study demonstrated for the first time impaired iron metabolism in human DMD cardiomyocytes, and potential reversal of this effect by correction of DMD mutation or pharmacological treatment. This implies that iron overload-regulating compounds may serve as novel therapeutic agents in DMD-associated cardiomyopathy.

Multi-omics analysis reveals that ferroptosis-related gene CISD2 is a prognostic biomarker of head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignancy, with high mortality rate and unavailability of accurate therapies. However, its early prevention remains a challenge. In the purview of predictive, preventive, and personalized medicine (PPPM), it is paramount to identify novel and powerful biomarkers. CISD2 is a crucial regulator of iron homeostasis and reactive oxygen species (ROS). Recent studies showed that the NEET protein (NAF-1) encoded by CISD2 is involved in regulating the proliferation and metastasis of tumor cells. Nevertheless, the prognostic value and immunological correlations of CISD2 remain unclear.

METHODS

Bioinformatics analyses conducted utilizing data from comprehensive databases The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). All statistical evaluations were executed employing R software.

RESULTS

Our investigation of biological function, enrichment pathway, and immune correlation revealed a discernable linkage between CISD2 and the immune response. Moreover, we found that the suppression of CISD2 is associated with immune cell infiltration and various immune signatures.

CONCLUSIONS

The present study successfully revealed the potential prognostic and biological function of CISD2 in HNSCC. High expression of CISD2 are linked to gender, race, grade, etc., can notably enhance the early detection, prognosis, and prediction for individuals afflicted with HNSCC.

CISD2 promotes lung squamous carcinoma cell migration and invasion via the TGF-β1-induced Smad2/3 signaling pathway

BACKGROUND

Although aberrant expression of CDGSH iron sulfur domain 2 (CISD2) contributes to the tumorigenesis and progression of numerous human cancers, the biological function of CISD2 and its specific prognostic value in lung squamous cell carcinoma (LUSC) have yet to be comprehensively explored. The current study aimed to elucidate the role of CISD2 in LUSC as well as the underlying molecular mechanisms.

METHODS

Immunohistochemistry was conducted to detect the protein expression of CISD2 and analyze whether high expression of CISD2 affects the overall survival (OS) of LUSC patients. Cell proliferation, colony formation, wound healing and Transwell invasion assays were performed to clarify whether CISD2 contributes to LUSC cell proliferation and disease progression. Quantitative real-time reverse transcription-PCR and western blot assays were used to detect the levels of transcription factors and key epithelial-mesenchymal transition (EMT)-related markers in LUSC cells after CISD2 knockdown and overexpression to determine whether CISD2 regulates transforming growth factor-beta (TGF-β)-induced EMT in LUSC.

RESULTS

Immunohistochemistry of human tissue microarrays containing 90 pairs of adjacent and cancerous tissues revealed that CISD2 is considerably overexpressed in LUSC and strongly linked to poor OS. Functional experiments suggested that silencing endogenous CISD2 inhibited the growth, colony formation, migration, and invasion of H2170 and H226 cell lines. Exogenous overexpression of CISD2 facilitated these phenotypes in SK-MES-1 and H2170 cells. Furthermore, CISD2 promoted EMT progression by increasing the expression of mesenchymal markers (N-cadherin, vimentin, Snail, and Slug) as well as SMAD2/3 and reducing the expression of the epithelial marker E-cadherin. Mechanistically, our studies provide the first evidence that CISD2 can promote EMT by enhancing TGF-β1-induced Smad2/3 expression in LUSC cells.

CONCLUSION

In conclusion, our research illustrates that CISD2 is highly expressed in LUSC and may facilitate LUSC proliferation and metastasis. Thus, CISD2 may serve as an independent prognostic marker and possible treatment target for LUSC.

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.

The Interplay between Mitochondrial Dysfunction and Ferroptosis during Ischemia-Associated Central Nervous System Diseases

Cerebral ischemia, a leading cause of disability and mortality worldwide, triggers a cascade of molecular and cellular pathologies linked to several central nervous system (CNS) disorders. These disorders primarily encompass ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and other CNS conditions. Despite substantial progress in understanding and treating the underlying pathological processes in various neurological diseases, there is still a notable absence of effective therapeutic approaches aimed specifically at mitigating the damage caused by these illnesses. Remarkably, ischemia causes severe damage to cells in ischemia-associated CNS diseases. Cerebral ischemia initiates oxygen and glucose deprivation, which subsequently promotes mitochondrial dysfunction, including mitochondrial permeability transition pore (MPTP) opening, mitophagy dysfunction, and excessive mitochondrial fission, triggering various forms of cell death such as autophagy, apoptosis, as well as ferroptosis. Ferroptosis, a novel type of regulated cell death (RCD), is characterized by iron-dependent accumulation of lethal reactive oxygen species (ROS) and lipid peroxidation. Mitochondrial dysfunction and ferroptosis both play critical roles in the pathogenic progression of ischemia-associated CNS diseases. In recent years, growing evidence has indicated that mitochondrial dysfunction interplays with ferroptosis to aggravate cerebral ischemia injury. However, the potential connections between mitochondrial dysfunction and ferroptosis in cerebral ischemia have not yet been clarified. Thus, we analyzed the underlying mechanism between mitochondrial dysfunction and ferroptosis in ischemia-associated CNS diseases. We also discovered that GSH depletion and GPX4 inactivation cause lipoxygenase activation and calcium influx following cerebral ischemia injury, resulting in MPTP opening and mitochondrial dysfunction. Additionally, dysfunction in mitochondrial electron transport and an imbalanced fusion-to-fission ratio can lead to the accumulation of ROS and iron overload, which further contribute to the occurrence of ferroptosis. This creates a vicious cycle that continuously worsens cerebral ischemia injury. In this study, our focus is on exploring the interplay between mitochondrial dysfunction and ferroptosis, which may offer new insights into potential therapeutic approaches for the treatment of ischemia-associated CNS diseases.

Mitochondrial miR-12294-5p regulated copper-induced mitochondrial oxidative stress and mitochondrial quality control imbalance by targeted inhibition of CISD1 in chicken livers

Copper (Cu) is hazardous metal contaminant, which induced hepatotoxicity is closely related to mitochondrial disorder, but exact regulatory mechanism has not yet been revealed. Mitochondrial microRNAs (mitomiRs) are a novel and critical regulator of mitochondrial function and mitochondrial homeostasis. Hence, this study revealed the impact of Cu-exposure on mitomiR expression profiles in chicken livers, and further identified mitomiR-12294-5p and its target gene CISD1 as core regulators involved in Cu-induced hepatotoxicity. Additionally, our results showed that Cu-exposure induced mitochondrial oxidative damage, and mitochondrial quality control imbalance mediated by mitochondrial dynamics disturbances, mitochondrial biogenesis inhibition and abnormal mitophagy flux in chicken livers and primary chicken embryo hepatocytes (CEHs). Meaningfully, we discovered that inhibition of the expression of mitomiR-12294-5p effectively alleviated Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance, while the up-regulation of mitomiR-12294-5p expression exacerbated Cu-induced mitochondrial damage. Simultaneously, the above Cu-induced mitochondrial damage can be effectively rescued by the overexpression of CISD1, while knockdown of CISD1 dramatically reverses the mitigating effect that inhibition of mitomiR-12294-5p expression on Cu-induced mitochondrial oxidative stress and mitochondrial quality control imbalance. Overall, these results suggested that mitomiR-12294-5p/CISD1 axis mediated mitochondrial damage is a novel molecular mechanism involved in regulating Cu-induced hepatotoxicity in chickens.

Mitochondrial iron regulation as an emerging target in ischemia/reperfusion injury during kidney transplantation

The injury caused by ischemia and subsequent reperfusion (I/R) is inevitable during kidney transplantation and its current management remains unsatisfactory. Iron is considered to play a remarkable pathologic role in the initiation or progression of tissue damage induced by I/R, whereas the effects of iron-related therapy remain controversial owing to the complicated nature of iron's involvement in multiple biological processes. A significant portion of the cellular iron is located in the mitochondria, which exerts a central role in the development and progression of I/R injury. Recent studies of iron regulation associated with mitochondrial function represents a unique opportunity to improve our knowledge on the pathophysiology of I/R injury. However, the molecular mechanisms linking mitochondria to the iron homeostasis remain unclear. In this review, we provide a comprehensive analysis of the alterations to iron metabolism in I/R injury during kidney transplantation, analyze the current understanding of mitochondrial regulation of iron homeostasis and discussed its potential application in I/R injury. The elucidation of regulatory mechanisms regulating mitochondrial iron homeostasis will offer valuable insights into potential therapeutic targets for alleviating I/R injury with the ultimate aim of improving kidney graft outcomes, with potential implications that could also extend to acute kidney injury or other I/R injuries.

A combination of a cell penetrating peptide and a protein translation inhibitor kills metastatic breast cancer cells

Cell Penetrating Peptides (CPPs) are promising anticancer and antimicrobial drugs. We recently reported that a peptide derived from the human mitochondrial/ER membrane-anchored NEET protein, Nutrient Autophagy Factor 1 (NAF-1; NAF-144-67), selectively permeates and kills human metastatic epithelial breast cancer cells (MDA-MB-231), but not control epithelial cells. As cancer cells alter their phenotype during growth and metastasis, we tested whether NAF-144-67 would also be efficient in killing other human epithelial breast cancer cells that may have a different phenotype. Here we report that NAF-144-67 is efficient in killing BT-549, Hs 578T, MDA-MB-436, and MDA-MB-453 breast cancer cells, but that MDA-MB-157 cells are resistant to it. Upon closer examination, we found that MDA-MB-157 cells display a high content of intracellular vesicles and cellular protrusions, compared to MDA-MB-231 cells, that could protect them from NAF-144-67. Inhibiting the formation of intracellular vesicles and dynamics of cellular protrusions of MDA-MB-157 cells, using a protein translation inhibitor (the antibiotic Cycloheximide), rendered these cells highly susceptible to NAF-144-67, suggesting that under certain conditions, the killing effect of CPPs could be augmented when they are applied in combination with an antibiotic or chemotherapy agent. These findings could prove important for the treatment of metastatic cancers with CPPs and/or treatment combinations that include CPPs.

The diversified role of mitochondria in ferroptosis in cancer

Ferroptosis is a form of regulated cell death induced by iron-dependent lipid peroxidation, and it has been studied extensively since its discovery in 2012. Induced by iron overload and ROS accumulation, ferroptosis is modulated by various cellular metabolic and signaling pathways. The GSH-GPX4 pathway, the FSP1-CoQ10 pathway, the GCH1-BH4 pathway, the DHODH-CoQH2 system and the sex hormones suppress ferroptosis. Mitochondrial iron metabolism regulates ferroptosis and mitochondria also undergo a morphological change during ferroptosis, these changes include increased membrane density and reduced mitochondrial cristae. Moreover, mitochondrial energy metabolism changes during ferroptosis, the increased oxidative phosphorylation and ATP production rates lead to a decrease in the glycolysis rate. In addition, excessive oxidative stress induces irreversible damage to mitochondria, diminishing organelle integrity. ROS production, mitochondrial membrane potential, mitochondrial fusion and fission, and mitophagy also function in ferroptosis. Notably, some ferroptosis inhibitors target mitochondria. Ferroptosis is a major mechanism for cell death associated with the progression of cancer. Metastasis-prone or metastatic cancer cells are more susceptible to ferroptosis. Inducing ferroptosis in tumor cells shows very promising potential for treating drug-resistant cancers. In this review, we present a brief retrospect of the discovery and the characteristics of ferroptosis, then we discuss the regulation of ferroptosis and highlight the unique role played by mitochondria in the ferroptosis of cancer cells. Furthermore, we explain how ferroptosis functions as a double-edged sword as well as novel therapies aimed at selectively manipulating cell death for cancer eradication.

HIF2α, Hepcidin and their crosstalk as tumour-promoting signalling

Not all aspects of the disruption of iron homeostasis in cancer have been fully elucidated. Iron accumulation in cancer cells is frequent for many solid tumours, and this is often accompanied by the contemporary rise of two key iron regulators, HIF2α and Hepcidin. This scenario is different from what happens under physiological conditions, where Hepcidin parallels systemic iron concentrations while HIF2α levels are inversely associated to Hepcidin. The present review highlights the increasing body of evidence for the pro-tumoral effect of HIF2α and Hepcidin, discusses the possible imbalance in HIF2α, Hepcidin and iron homeostasis during cancer, and explores therapeutic options relying on these pathways as anticancer strategies.

Mechanism of sorafenib resistance associated with ferroptosis in HCC

Hepatocellular carcinoma (HCC) is the most familiar primary hepatic malignancy with a poor prognosis. The incidence of HCC and the associated deaths have risen in recent decades. Sorafenib is the first drug to be approved by the Food and Drug Administration (FDA) for routine use in the first-line therapy of patients with advanced HCC. However, only about 30% of patients with HCC will be benefited from sorafenib therapy, and drug resistance typically develops within 6 months. In recent years, the mechanisms of resistance to sorafenib have gained the attention of a growing number of researchers. A promising field of current studies is ferroptosis, which is a novel form of cell death differing from apoptosis, necroptosis, and autophagy. This process is dependent on the accumulation of intracellular iron and reactive oxygen species (ROS). Furthermore, the increase in intracellular iron levels and ROS can be significantly observed in cells resistant to sorafenib. This article reviews the mechanisms of resistance to sorafenib that are related to ferroptosis, evaluates the relationship between ferroptosis and sorafenib resistance, and explores new therapeutic approaches capable of reversing sorafenib resistance in HCC through the modulation of ferroptosis.

Dysfunctions, molecular mechanisms, and therapeutic strategies of pancreatic β-cells in diabetes

Pancreatic beta-cell death has been established as a critical mediator in the progression of type 1 and type 2 diabetes mellitus. Beta-cell death is associated with exacerbating hyperglycemia and insulin resistance and paves the way for the progression of DM and its complications. Apoptosis has been considered the primary mechanism of beta-cell death in diabetes. However, recent pieces of evidence have implicated the substantial involvement of several other novel modes of cell death, including autophagy, pyroptosis, necroptosis, and ferroptosis. These distinct mechanisms are characterized by their unique biochemical features and often precipitate damage through the induction of cellular stressors, including endoplasmic reticulum stress, oxidative stress, and inflammation. Experimental studies were identified from PubMed literature on different modes of beta cell death during the onset of diabetes mellitus. This review summarizes current knowledge on the crucial pathways implicated in pancreatic beta cell death. The article also focuses on applying natural compounds as potential treatment strategies in inhibiting these cell death pathways.

CISD3 is required for Complex I function, mitochondrial integrity, and skeletal muscle maintenance

Mitochondria play a central role in muscle metabolism and function. In skeletal muscles, a unique family of iron-sulfur proteins, termed CISD proteins, support mitochondrial function. The abundance of these proteins declines with aging leading to muscle degeneration. Although the function of the outer mitochondrial proteins CISD1 and CISD2 has been defined, the role of the inner mitochondrial protein CISD3, is currently unknown. Here we show that CISD3 deficiency in mice results in muscle atrophy that shares proteomic features with Duchenne Muscular Dystrophy. We further reveal that CISD3 deficiency impairs the function and structure of skeletal muscle mitochondria, and that CISD3 interacts with, and donates its clusters to, Complex I respiratory chain subunit NDUFV2. These findings reveal that CISD3 is important for supporting the biogenesis and function of Complex I, essential for muscle maintenance and function. Interventions that target CISD3 could therefore impact muscle degeneration syndromes, aging, and related conditions.

1H, 13C and 15N assignment of the human mitochondrial paramagnetic iron-sulfur protein CISD3

CISD3 is a mitochondrial protein that contains two [2Fe-2S] clusters. This protein is overexpressed in some types of cancer, so it has emerged as a potential drug target. A detailed characterization of this protein is crucial to understand how CISD3 is involved in these physiopathologies. In this study, isotopically labeled human CISD3 was expressed in Escherichia coli. A set of double and triple resonance experiments performed with standard parameters/datasets provided the assignment of 40% of the HN resonances, 47% of Cα, and 46% of C' resonances. Tailored paramagnetic HSQC, CON and CACO experiments extended up to 59% for HN, 70% for Cα and 69% for C'. The ¹H, ¹³C and ¹⁵N NMR chemical shift assignment of human CISD3 is reported here.

Targeting Iron-Sulfur Clusters in Cancer: Opportunities and Challenges for Ferroptosis-Based Therapy

Iron dysregulation is a hallmark of cancer, characterized by an overexpression of genes involved in iron metabolism and iron-sulfur cluster (ISC) biogenesis. Dysregulated iron homeostasis increases intracellular labile iron, which may lead to the formation of excess cytotoxic radicals and make it vulnerable to various types of regulated cell death, including ferroptosis. The inhibition of ISC synthesis triggers the iron starvation response, increasing lipid peroxidation and ferroptosis in cancer cells treated with oxidative stress-inducing agents. Various methods, such as redox operations, iron chelation, and iron replacement with redox-inert metals, can destabilize or limit ISC formation and function, providing potential therapeutic strategies for cancer treatment. Targeting ISCs to induce ferroptosis represents a promising approach in cancer therapy. This review summarizes the state-of-the-art overview of iron metabolism and ferroptosis in cancer cells, the role of ISC modulation in ferroptosis, and the potential of targeting ISCs for ferroptosis induction in cancer therapy. Further research is necessary to develop and validate these strategies in clinical trials for various cancers, which may ultimately lead to the development of novel and effective treatments for cancer patients.

Identification of a m6A-related ferroptosis signature as a potential predictive biomarker for lung adenocarcinoma

BACKGROUND

Both N6-methyladenosine (m⁶A) and ferroptosis-related genes are associated with the prognosis of lung adenocarcinoma. However, the predictive value of m⁶A-related ferroptosis genes remains unclear. Here, we aimed to identify the prognostic value of m⁶A-related ferroptosis genes in lung adenocarcinoma.

METHODS

Lung adenocarcinoma sample data were downloaded from the University of California Santa Cruz Xena and Gene Expression Omnibus databases. Spearman's correlation analysis was used to screen for m⁶A-related ferroptosis genes. Univariate Cox regression, Kaplan-Meier, and Lasso analyses were conducted to identify prognostic m⁶A-related ferroptosis genes, and stepwise regression was used to construct a prognostic gene signature. The predictive value of the gene signature was assessed using a multivariate Cox analysis. In the validation cohort, survival analysis was performed to verify gene signature stability. The training cohort was divided into high- and low-risk groups according to the median risk score to assess differences between the two groups in terms of gene set variation analysis, somatic mutations, and tumor immune infiltration cells.

RESULTS

Six m⁶A-related ferroptosis genes were used to construct a gene signature in the training cohort and a multivariate Cox analysis was conducted to determine the independent prognostic value of these genes in lung adenocarcinoma. In the validation cohort, Kaplan-Meier and receiver operating characteristic analyses confirmed the strong predictive power of this signature for the prognosis of lung adenocarcinoma. Gene set variation analysis showed that the low-risk group was mainly related to immunity, and the high-risk group was mainly related to DNA replication. Somatic mutation analysis revealed that the TP53 gene had the highest mutation rate in the high-risk group. Tumor immune infiltration cell analysis showed that the low-risk group had higher levels of resting CD4 memory T cells and lower levels of M0 macrophages.

CONCLUSION

Our study identified a novel m⁶A-related ferroptosis-associated six-gene signature (comprising SLC2A1, HERPUD1, EIF2S1, ACSL3, NCOA4, and CISD1) for predicting lung adenocarcinoma prognosis, yielding a useful prognostic biomarker and potential therapeutic target.

Mitoglitazone ameliorates renal ischemia/reperfusion injury by inhibiting ferroptosis via targeting mitoNEET

Ischemia/reperfusion- (I/R-) induced injury is unavoidable and a major risk factor for graft failure and acute rejection following kidney transplantation. However, few effective interventions are available to improve the outcome due to the complicated mechanisms and lack of appropriate therapeutic targets. Hence, this research aimed to explore the effect of the thiazolidinedione (TZD) compounds on I/R-induced kidney damage. One of the main causes of renal I/R injury is the ferroptosis of renal tubular cells. In this study, compared with the antidiabetic TZD pioglitazone (PGZ), we found its derivative mitoglitazone (MGZ) exerted significantly inhibitory effects on erastin-induced ferroptosis by suppressing mitochondrial membrane potential hyperpolarization and lipid ROS production in HEK293 cells. Moreover, MGZ pretreatment remarkably alleviated I/R-induced renal damages by inhibiting cell death and inflammation, upregulating the expression of glutathione peroxidase 4 (GPX4), and reducing iron-related lipid peroxidation in C57BL/6 N mice. Additionally, MGZ exhibited excellent protection against I/R-induced mitochondrial dysfunction by restoring ATP production, mitochondrial DNA copy numbers, and mitochondrial morphology in kidney tissues. Mechanistically, molecular docking and surface plasmon resonance experiments demonstrated that MGZ exhibited a high binding affinity with the mitochondrial outer membrane protein mitoNEET. Collectively, our findings indicated the renal protective effect of MGZ was closely linked to regulating the mitoNEET-mediated ferroptosis pathway, thus offering potential therapeutic strategies for ameliorating I/R injuries.

Biochemical Control of the Mitochondrial Protein MitoNEET by Biological Thiols and Lipid-derived Electrophiles

MitoNEET is a mitochondrial [2Fe-2S] protein known for its involvement in cellular metabolism, iron regulation, and oxidative stress. The protein has been associated with diseases ranging from diabetes to Parkinson's disease which has prompted development of compounds designed to selectively target mitoNEET. Unfortunately, drug development is limited due to a lack of understanding on the mechanistic level how mitoNEET integrates into pathophysiological processes. In particular, biological compounds that govern mitoNEET function are still ill defined. We demonstrate an oxygen-dependent reaction with biological thiols catalyzed by mitoNEET. Furthermore, we observed that formation of a covalently linked mitoNEET homodimer is controlled by both thiols and lipid-derived electrophiles. Finally, we demonstrate that reduced glutathione (L-GSH) regulates the reactivity of two lipid-derived biomarkers of oxidative stress, 4-HNE and 4-ONE, towards mitoNEET. We find that exposure to L-GSH prior to treatment with either of the electrophilic aldehydes prevents the formation of the covalently linked mitoNEET dimer. Meanwhile, addition of L-GSH after electrophile treatment recovers mitoNEET from the 4-HNE induced modification but not from the modification induced by 4-ONE. Our results collectively suggest that the thiol-electrophile redox balance governing ferroptotic cell death also controls mitoNEET's state at multiple biochemical levels. These results indicate a possible role for mitoNEET in thiol-mediated oxidative stress and may inform about development of probes designed to modulate mitoNEET activity to improve pathophysiological states.

FGF4 improves hepatocytes ferroptosis in autoimmune hepatitis mice via activation of CISD3

Autoimmune hepatitis (AIH) is increasingly affecting human health but pharmacotherapies remain to be identified. Growing evidence reveals that ferroptosis, a newly recognized form of programmed cell death, is critical for AIH. However, the exact mechanisms of the ferroptotic cascade remain elusive. Data in this study showed that ferroptosis aggravation was associated with protectively-elevated fibroblast growth factor 4 (FGF4) expression in Concanavalin A (ConA)-induced AIH liver injury, with these effects being effectively reversed by Ferrostatin-1 (Fer-1). Moreover, hepatic Fgf4 depletion was more susceptible to lipid peroxidation and iron accumulation, as well as hepatic lesion and inflammation caused by ConA administration. Conversely, treatment with non-mitogenic recombinant FGF4 (rFGF4) mitigated liver damage and hepatocellular ferroptosis while being accompanied by the upregulation of CDGSH iron-sulfur domain-containing protein 3 (CISD3) in vivo and in vitro. Furthermore, CISD3 overexpression exhibited stronger resistance to ferroptosis while CISD3 knockdown reduced ferroptotic biomarkers cystine/glutamate transporter (xCT) and glutathione peroxidase 4（GPX4) in rFGF4-treated Erastin-induced AML12 cells. In addition, rFGF4 significantly enhanced the levels of heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) in ConA-induced AIH mice. Overall, this study showed that FGF4 can act as a phylactic role in AIH progression, with rFGF4 treatment inhibiting ferroptosis of hepatocytes by increasing CISD3 levels and activating Nrf2/HO-1 signaling.

Lactobacillus johnsonii L531 Ameliorates Salmonella enterica Serovar Typhimurium Diarrhea by Modulating Iron Homeostasis and Oxidative Stress via the IRP2 Pathway

Salmonella enterica serovar Typhimurium (S. Typhimurium) has evolved mechanisms to evade the host's nutritional immunity and thus promote bacterial growth by using the iron in the host. However, the detailed mechanisms of S. Typhimurium induce dysregulation of iron homeostasis and whether Lactobacillus johnsonii L531 can alleviate the iron metabolism disorder caused by S. Typhimurium has not been fully elucidated. Here, we show that S. Typhimurium activated the expression of iron regulatory protein 2 (IRP2), transferrin receptor 1, and divalent metal transporter protein 1 and suppressed the expression of iron exporter ferroportin, which resulted in iron overload and oxidative stress, inhibiting the key antioxidant proteins NF-E2-related factor 2, Heme Oxygenase-1, and Superoxide Dismutase in vitro and in vivo. L. johnsonii L531 pretreatment effectively reversed these phenomena. IRP2 knockdown inhibited iron overload and oxidative damage induced by S. Typhimurium in IPEC-J2 cells, while IRP2 overexpression promoted iron overload and oxidative damage caused by S. Typhimurium. Interestingly, the protective effect of L. johnsonii L531 on iron homeostasis and antioxidant function was blocked following IRP2 overexpression in Hela cells, demonstrating that L. johnsonii L531 attenuates disruption of iron homeostasis and consequent oxidative damage caused by S. Typhimurium via the IRP2 pathway, which contributes to the prevention of S. Typhimurium diarrhea in mice.

CDGSH iron sulfur domain 2 over-expression alleviates neuronal ferroptosis and brain injury by inhibiting lipid peroxidation via AKT/mTOR pathway following intracerebral hemorrhage in mice

Ferroptosis has been implicated in the pathogenesis of secondary brain injury following intracerebral hemorrhage (ICH), and regulating this process is considered a potential therapy for alleviating further brain injury. A previous study showed that CDGSH iron sulfur domain 2 (CISD2) can inhibit ferroptosis in cancer. Thus, we investigated the effects of CISD2 on ferroptosis and the mechanisms underlying its neuroprotective role in mice after ICH. CISD2 expression markedly increased after ICH. CISD2 over-expression significantly decreased the number of Fluoro-Jade C-positive neurons and alleviated brain edema and neurobehavioral deficits at 24 h after ICH. In addition, CISD2 over-expression up-regulated the expression of p-AKT, p-mTOR, ferritin heavy chain 1, glutathione peroxidase 4, ferroportin, glutathione, and glutathione peroxidase activity, which are markers of ferroptosis. Additionally, CISD2 over-expression down-regulated the levels of malonaldehyde, iron content, acyl-CoA synthetase long-chain family member 4, transferrin receptor 1, and cyclooxygenase-2 at 24 h after ICH. It also alleviated mitochondrial shrinkage and decreased the density of the mitochondrial membrane. Furthermore, CISD2 over-expression increased the number of GPX4-positive neurons following ICH induction. Conversely, knockdown of CISD2 aggravated neurobehavioral deficits, brain edema, and neuronal ferroptosis. Mechanistically, MK2206, an AKT inhibitor, suppressed p-AKT and p-mTOR and reversed the effects of CISD2 over-expression on markers of neuronal ferroptosis and acute neurological outcome. Taken together, CISD2 over-expression alleviated neuronal ferroptosis and improved neurological performance, which may be mediated through the AKT/mTOR pathway after ICH. Thus, CISD2 may be a potential target to mitigate brain injury via the anti-ferroptosis effect after ICH.

Coupling of autophagy and the mitochondrial intrinsic apoptosis pathway modulates proteostasis and ageing in Caenorhabditis elegans

Mitochondria preserve metabolic homeostasis and integrate stress signals, to trigger cytoprotective, or cell death pathways. Mitochondrial homeostasis and function decline with age. The mechanisms underlying the deterioration of mitochondrial homeostasis during ageing, or in age-associated pathologies, remain unclear. Here, we show that CISD-1, a mitochondrial iron-sulfur cluster binding protein, implicated in the pathogenesis of Wolfram neurodegenerative syndrome type 2, modulates longevity in the nematode Caenorhabditis elegans by engaging autophagy and the mitochondrial intrinsic apoptosis pathway. The anti-apoptotic protein CED-9 is the downstream effector that mediates CISD-1-dependent effects on proteostasis, neuronal integrity and lifespan. Moreover, intracellular iron abundance is critical for CISD-1 function, since mild iron supplementation is sufficient to decelerate ageing and partly ameliorate the disturbed mitochondrial bioenergetics and proteostasis of CISD-1 deficient animals. Our findings reveal that CISD-1 serves as a mechanistic link between autophagy and the apoptotic pathway in mitochondria to differentially modulate organismal proteostasis and ageing, and suggest novel approaches which could facilitate the treatment of Wolfram Syndrome or related diseases.

Relaxation-based NMR assignment: Spotlights on ligand binding sites in human CISD3

CISD3 is a mitochondrial protein belonging to the NEET proteins family, bearing two [Fe₂S₂] clusters coordinated by CDGSH domains. At variance with the other proteins of the NEET family, very little is known about its structure-function relationships. NMR is the only technique to obtain information at the atomic level in solution on the residues involved in intermolecular interactions; however, in paramagnetic proteins this is limited by the broadening of signals of residues around the paramagnetic center. Tailored experiments can revive signals of the cluster surrounding; however, signals identification without specific residue assignment remains useless. Here, we show how paramagnetic relaxation can drive the signal assignment of residues in the proximity of the paramagnetic center(s). This allowed us to identify the potential key players of the biological function of the CISD3 protein.

Maintenance of genome integrity by the late-acting cytoplasmic iron-sulfur assembly (CIA) complex

Iron-sulfur (Fe-S) clusters are unique, redox-active co-factors ubiquitous throughout cellular metabolism. Fe-S cluster synthesis, trafficking, and coordination result from highly coordinated, evolutionarily conserved biosynthetic processes. The initial Fe-S cluster synthesis occurs within the mitochondria; however, the maturation of Fe-S clusters culminating in their ultimate insertion into appropriate cytosolic/nuclear proteins is coordinated by a late-acting cytosolic iron-sulfur assembly (CIA) complex in the cytosol. Several nuclear proteins involved in DNA replication and repair interact with the CIA complex and contain Fe-S clusters necessary for proper enzymatic activity. Moreover, it is currently hypothesized that the late-acting CIA complex regulates the maintenance of genome integrity and is an integral feature of DNA metabolism. This review describes the late-acting CIA complex and several [4Fe-4S] DNA metabolic enzymes associated with maintaining genome stability.