The ferroptosis inducer erastin promotes proliferation and differentiation in human peripheral blood mononuclear cells

Identification of new hub- ferroptosis-related genes in Lupus Nephritis

Background: Lupus Nephritis (LN) is the primary causation of kidney injury in systemic lupus erythematosus (SLE). Ferroptosis is a programmed cell death. Therefore, understanding the crosstalk between LN and ferroptosis is still a significant challenge. Methods: We obtained the expression profile of LN kidney biopsy samples from the Gene Expression Omnibus database and utilised the R-project software to identify differentially expressed genes (DEGs). Then, we conducted a functional correlation analysis. Ferroptosis-related genes (FRGs) and differentially expressed genes (DEGs) crossover to select FRGs with LN. Afterwards, we used CIBERSORT to assess the infiltration of immune cells in both LN tissues and healthy control samples. Finally, we performed immunohistochemistry on LN human renal tissue. Results: 10619 DEGs screened from the LN biopsy tissue were identified. 22 hub-ferroptosis-related genes with LN (FRGs-LN) were screened out. The CIBERSORT findings revealed that there were significant statistical differences in immune cells between healthy control samples and LN tissues. Immunohistochemistry further demonstrated a significant difference in HRAS, TFRC, ATM, and SRC expression in renal tissue between normal and control groups. Conclusion: We developed a signature that allowed us to identify 22 new biomarkers associated with FRGs-LN. These findings suggest new insights into the pathology and therapeutic potential of LN ferroptosis inhibitors and iron chelators.

Saracatinib prompts hemin-induced K562 erythroid differentiation but suppresses erythropoiesis of hematopoietic stem cells

Human myeloid leukemia cells (such as K562) could be used for the study of erythropoiesis, and mature erythroid markers and globins could be induced during leukemia cell differentiation; however, the pathways involved are different compared with those of hematopoietic stem cells (HSCs).We identified the differentially expressed genes (DEGs) of K562 cells and HSCs associated with stem cells and erythroid differentiation. Furthermore, we showed that hemin-induced differentiation of K562 cells could be induced by serum starvation or treatment with the tyrosine kinase inhibitor saracatinib. However, erythroid differentiation of HSCs was inhibited by the deprivation of the important serum component erythropoietin (EPO) or treatment with saracatinib. Finally, we found that the mRNA expression of K562 cells and HSCs was different during saracatinib-treated erythroid differentiation, and the DEGs of K562 cells and HSCs associated with tyrosine-protein kinase were identified.These findings elucidated the cellular phenomenon of saracatinib induction during erythroid differentiation of K562 cells and HSCs, and the potential mechanism is the different mRNA expression profile of tyrosine-protein kinase in K562 cells and HSCs.

Mitochondria-Specific Molecular Crosstalk between Ferroptosis and Apoptosis Revealed by In Situ Raman Spectroscopy

Ferroptosis and apoptosis are two types of regulated cell death that are closely associated with the pathophysiological processes of many diseases. The significance of ferroptosis-apoptosis crosstalk in cell fate determination has been reported, but the underlying molecular mechanisms are poorly understood. Herein mitochondria-mediated molecular crosstalk is explored. Based on a comprehensive spectroscopic investigation and mass spectrometry, cytochrome c-involved Fenton-like reactions and lipid peroxidation are revealed. More importantly, cytochrome c is found to induce ROS-independent and cardiolipin-specific lipid peroxidation depending on its redox state. In situ Raman spectroscopy unveiled that erastin can interrupt membrane permeability, specifically through cardiolipin, facilitating cytochrome c release from the mitochondria. Details of the erastin-cardiolipin interaction are determined using molecular dynamics simulations. This study provides novel insights into how molecular crosstalk occurs around mitochondrial membranes to trigger ferroptosis and apoptosis, with significant implications for the rational design of mitochondria-targeted cell death reducers in cancer therapy.

Ferroptosis in cardiovascular diseases: role and mechanism

In multicellular organisms, regulatory cell death is a crucial aspect of growth and development. Ferroptosis, which was postulated roughly ten years ago, is a mode of cell death that differs from apoptosis, autophagy, and pyrodeath. This distinct pattern of cell death is triggered by an imbalance between oxidants and antioxidants and strongly associated with the metabolism of iron, lipids, amino acids, and glutathione. A growing body of research has implicated ferroptosis in the incidence and progression of many organ traumas and degenerative diseases. Recently, ferroptosis has gained attention as a crucial regulatory mechanism underlying the initiation and development of a variety of cardiovascular diseases, including myocardial ischemia/reperfusion injury, cardiomyopathy, arrhythmia, chemotherapy, and Corona Virus-2-induced cardiac injury. Pharmacological therapies that inhibit ferroptosis have great potential for the management of cardiovascular disorders. This review discusses the prevalence and regulatory mechanisms of ferroptosis, effect of ferroptosis on the immune system, significance of ferroptosis in cardiovascular diseases, and potential therapeutic value of regulating ferroptosis in a variety of heart diseases.

Ferroptosis: A potential therapeutic target in autoimmune disease (Review)

Ferroptosis is a distinct type of regulated cell death characterized by iron overload and lipid peroxidation. Ferroptosis is regulated by numerous factors and controlled by several mechanisms. This cell death type has a relationship with the immune system, which may be regulated by damage-associated molecular patterns. Ferroptosis participates in the progression of autoimmune diseases, including autoimmune hepatitis, rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, multiple sclerosis, Parkinson's Disease, psoriasis and insulin-dependent diabetes mellitus. The present review summarizes the role of ferroptosis in autoimmune disorders and discusses ferroptosis as a potential therapeutic target for autoimmune disease.

Emerging insights into the role of ferroptosis in the pathogenesis of autoimmune diseases

Ferroptosis, a novel type of regulated cell death mediated by iron-dependent lipid oxidation, was discovered a decade ago. Significant progress has been made in our knowledge of ferroptosis and immune dysfunction. This review covers recent advancements in the interaction of ferroptosis and the immune system, with an emphasis on autoimmune diseases. The critical regulators of ferroptosis are summarized in the context of reactive oxygen species biology, lipid metabolism, and iron homeostasis. The molecular crosstalk between ferroptosis and different immune cells is also highlighted. Future research is expected to yield new insights into the mechanisms governing ferroptosis and its potential therapeutic benefits in autoimmune diseases.

The crosslinks between ferroptosis and autophagy in asthma

Autophagy is an evolutionarily conserved cellular process capable of degrading various biological molecules and organelles via the lysosomal pathway. Ferroptosis is a type of oxidative stress-dependent regulated cell death associated with the iron accumulation and lipid peroxidation. The crosslinks between ferroptosis and autophagy have been focused on since the dependence of ferroptosis on autophagy was discovered. Although the research and theories on the relationship between autophagy and ferroptosis remain scattered and fragmented, the crosslinks between these two forms of regulated cell death are closely related to the treatment of various diseases. Thereof, asthma as a chronic inflammatory disease has a tight connection with the occurrence of ferroptosis and autophagy since the crosslinked signal pathways may be the crucial regulators or exactly regulated by cells and secretion in the immune system. In addition, non-immune cells associated with asthma are also closely related to autophagy and ferroptosis. Further studies of cross-linking asthma inflammation with crosslinked signaling pathways may provide us with several key molecules that regulate asthma through specific regulators. The crosslinks between autophagy and ferroptosis provide us with a new perspective to interpret and understand the manifestations of asthma, potential drug discovery targets, and new therapeutic options to effectively intervene in the imbalance caused by abnormal inflammation in asthma. Herein, we introduce the main molecular mechanisms of ferroptosis, autophagy, and asthma, describe the role of crosslinks between ferroptosis and autophagy in asthma based on their common regulatory cells or molecules, and discuss potential drug discovery targets and therapeutic applications in the context of immunomodulatory and symptom alleviation.

Erastin inhibits porcine epidemic diarrhea virus replication in Vero cells

Background

Porcine epidemic diarrhea virus (PEDV), an intestinal pathogenic coronavirus, has caused significant economic losses to the swine industry worldwide. At present, there are several treatment methods, but there is still a lack of clinically effective targeted drugs, new antiviral mechanisms and drugs need to be explored.

Methods

In this study, we established a model of erastin versus ferrostatin-1 treatment of Vero cells, and then detected virus proliferation and gene expression by RT-qPCR through PEDV infection experiments.

Results

We demonstrated for the first time that erastin significantly inhibited the replication of PEDV upon entry into cells; Vero treated with erastin significantly regulated the expression of three genes, NRF2, ACSL4 and GPX4, notably erastin regulated the expression of these three genes negatively correlated with the expression induced by PEDV virus infection.

Conclusions

Since NRF2, ACSL4 and GPX4 are classical Ferroptosis genes, this study speculates that erastin may inhibit the replication of PEDV in Vero cells in part through the regulation of ferroptosis pathway, and erastin may be a potential drug for the treatment of PEDV infection.

Identification of ferroptosis‑associated genes in chronic kidney disease

Ferroptosis serves a pivotal role in developing chronic kidney disease (CKD). The present study aimed to detect and confirm the relevance of potential ferroptosis-related genes in CKD using bioinformatics and experimentation strategies. The original GSE15072 mRNA expression dataset was retrieved from the Gene Expression Omnibus database. Subsequently, the potential differentially expressed genes associated with ferroptosis of CKD were screened using R software. Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses, correlation analysis and protein-protein interactions (PPI) were performed for differentially expressed ferroptosis-associated genes (DFGs). Lastly, the expression levels of the top nine DFGs were measured in the kidney tissue of Adriamycin-induced CKD rats and healthy controls via reverse transcription-quantitative (RT-q)PCR analysis. Overall, 49 DFGs among 21 patients with CKD and nine healthy controls were identified. GO and KEGG enrichment analyses demonstrated that these DFGs were primarily involved in 'ferroptosis' and 'mitophagy'. PPI findings indicated that these ferroptosis-associated genes interacted with one another. RT-qPCR of CKD tissue from the rat model revealed that STAT3, MAPK14, heat shock protein (HSP)A5, MTOR and solute carrier family 2 member 1 (SLC2A1) mRNA levels in CKD were upregulated. Overall, 49 potential ferroptosis-associated genes of CKD were identified via bioinformatics analyses. STAT3, MAPK14, HSPA5, MTOR and SLC2A1 may influence CKD onset by regulating ferroptosis. The present results add to the existing body of knowledge about CKD and may be useful in the treatment of CKD.

Ferroptosis-related gene signature predicts prognosis in kidney renal papillary cell carcinoma

Ferroptosis, an iron-dependent form of selective cell death, is involved in the development of many cancers. However, the role of ferroptosis-related genes (FRGs) in kidney renal papillary cell carcinoma (KIRP) is unclear. In this study, we examined the mRNA expression profiles and clinical data of patients with KIRP from the TCGA cohort. Consequently, 41 differentially-expressed FRGs were screened using the limma package, and 17 prognostic-related FRGs were identified by survival analysis and univariate Cox regression analyses. Thereafter, a ferroptosis-related gene prognostic index (FRGPI) was constructed based on five FRGs (AKR1C3, SAT1, FANCD2, HSBP1 and SQLE), using lasso Cox and multivariate Cox regression analyses. KIRP patients with high FRGPI scores displayed worse outcomes. Furthermore, the FRGPI was shown to be a reliable independent prognostic factor in both the training and testing cohorts. Comprehensive analysis also showed that the FRGPI can distinguish gene mutation, functional enrichment of immune cells and molecular function-related pathways. Interestingly, low FRGPI score could be more benefit from immune checkpoint inhibitors (ICIs) therapy. Then, the two hub prognostic genes (AKR1C3 and FANCD2) as a risk gene for KIRP were identified based on the FRGPI module, and the expression profiles of these two genes were validated using human KIRP cells, besides, we furthermore discovered that Fancd2 is significantly up-regulated in most cancers and is associated with prognosis. In conclusion, these findings showed that FRGPI can accurately predict the prognosis of patients with KIRP, suggesting that this risk model is a promising prognostic biomarker for these patients. Moreover, targeting ferroptosis (FANCD2) could be a potential therapeutic alternative for various cancers.

Ferroptosis: A potential opportunity for intervention of pre-metastatic niche

It is widely thought that the tumor microenvironment (TME) provides the “soil” for malignant tumors to survive. Prior to metastasis, the interaction at the host site between factors secreted by primary tumors, bone-marrow-derived cells, with stromal components initiates and establishes a pre-metastatic niche (PMN) characterized by immunosuppression, inflammation, angiogenesis and vascular permeability, as well as lymphangiogenesis, reprogramming and organotropism. Ferroptosis is a non-apoptotic cell death characterized by iron-dependent lipid peroxidation and metabolic constraints. Ferroptotic cancer cells release various signal molecules into the TME to either suppress or promote tumor progression. This review highlights the important role played by ferroptosis in PMN, focusing on the relationship between ferroptosis and PMN characteristics, and discusses future research directions.

Establishment of a prognostic ferroptosis- and immune-related long noncoding RNAs profile in kidney renal clear cell carcinoma

Background: Ferroptosis and immunity are novel treatments that target several cancers, including kidney renal clear cell carcinoma (KIRC). Long noncoding RNAs (lncRNAs) are an important class of gene expression regulators that play fundamental roles in the regulation of ferroptosis and immunity. We aimed to identify ferroptosis- and immune-related lncRNAs as biomarkers in patients with KIRC.

Methods: Corresponding data for each patient with KIRC were obtained from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analyses were used to identify candidate biomarkers followed by least absolute shrinkage and selection operator (LASSO) regression analyses, weighted gene coexpression network analysis (WGCANA), and gene set enrichment analysis (GSEA).

Results: Three ferroptosis- and immune-related differentially expressed lncRNAs (FI-DELs) (AC124854.1, LINC02609, and ZNF503-AS2) were markedly and independently correlated with the overall survival (OS) of patients with KIRC. The area under the curve (AUC) value of the prognostic model in the entire group using the three FI-DELs was > 0.70. The sensitivity and specificity of the diagnostic model using the three FI-DELs were 0.8586 and 0.9583, respectively.

Conclusion: The present study found that AC124854.1, LINC02609, and ZNF503-AS2 were considerably and independently correlated with the OS of patients with KIRC, suggesting that the three FI-DELs could be used as prognostic and diagnostic biomarkers for patients with KIRC.

Identification of immune-related ferroptosis prognostic marker and in-depth bioinformatics exploration of multi-omics mechanisms in thyroid cancer

Background: Factors such as variations in thyroid carcinoma (THCA) gene characteristics could influence the clinical outcome. Ferroptosis and immunity have been verified to play an essential role in various cancers, and could affect the cancer patients’ prognosis. However, their relationship to the progression and prognosis of many types of THCA remains unclear.

Methods: First, we extracted prognosis-related immune-related genes and ferroptosis-related genes from 2 databases for co-expression analysis to obtain prognosis-related differentially expressed immune-related ferroptosis genes (PR-DE-IRFeGs), and screened BID and CDKN2A for building a prognostic model. Subsequently, multiple validation methods were used to test the model’s performance and compare its performance with other 4 external models. Then, we explored the mechanism of immunity and ferroptosis in the occurrence, development and prognosis of THCA from the perspectives of anti-tumor immunity, CDKN2A-related competitive endogenous RNA regulatory, copy number variations and high frequency gene mutation. Finally, we evaluated this model’s clinical practice value.

Results: BID and CDKN2A were identified as prognostic risk and protective factors, respectively. External data and qRT-PCR experiment also validated their differential expression. The model’s excellent performance has been repeatedly verified and outperformed other models. Risk scores were significantly associated with most immune cells/functions. Risk score/2 PR-DE-IRFeGs expression was strongly associated with BRAF/NRAS/HRAS mutation. Single copy number deletion of CDKN2A is associated with upregulation of CDKN2A expression and worse prognosis. The predicted regulatory network consisting of CYTOR, hsa-miRNA-873-5p and CDKN2A was shown to significantly affect prognosis. The model and corresponding nomogram have been shown to have excellent clinical practice value.

Conclusion: The model can effectively predict the THCA patients’ prognosis and guide clinical treatment. Ferroptosis and immunity may be involved in the THCA’s progression through antitumor immunity and BRAF/NRAS/HRAS mutation. CYTOR-hsa-miRNA-873-5p-CDKN2A regulatory networks and single copy number deletion of CDKN2A may also affect THCA′ progression and prognosis.

Pathological mechanisms and crosstalk among different forms of cell death in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder characterized by a profound immune dysregulation and the presence of a variety of autoantibodies. Aberrant activation of programmed cell death (PCD) signaling and accelerated cell death is critical in the immunopathogenesis of SLE. Accumulating cellular components from the dead cells and ineffective clearance of the dead cell debris, in particular the nucleic acids and nucleic acids-protein complexes, provide a stable source of self-antigens, which potently activate auto-reactive B cells and promote IFN-I responses in SLE. Different cell types display distinct susceptibility and characteristics to a certain type of cell death, while different PCDs in various cells have mutual and intricate connections to promote immune dysregulation and contribute to the development of SLE. In this review, we discuss the role of various cell death pathways and their interactions in the pathogenesis of SLE. An in depth understanding of the interconnections among various forms cell death in SLE will lead to a better understanding of disease pathogenesis, shedding light on the development of novel therapeutic targets.

Comprehensive Analysis of Ferroptosis- and Immune-Related Signatures to Improve the Prognosis and Diagnosis of Kidney Renal Clear Cell Carcinoma

Background

Almost 40% of patients with kidney renal clear cell carcinoma (KIRC) with advanced cancers eventually develop to metastases, and their 5-year survival rates are approximately 10%. Aberrant DNA methylations are significantly associated with the development of KIRC. The aim of our present study was to identify suitable ferroptosis- and immune-related (FI) biomarkers correlated with aberrant methylations to improve the prognosis and diagnosis of KIRC.

Methods

ChAMP and DESeq2 in R (3.6.2) were used to screen the differentially expressed methylation probes and differentially expressed genes, respectively. Univariate and multivariate Cox regression were used to identify the overall survival (OS)-related biomarkers.

Results

We finally identified five FI biomarkers (CCR4, CMTM3, IFITM1, MX2, and NR3C2) that were independently correlated with the OS of KIRC. The area under the curve value of the receiver operating characteristic value of prognosis model was 0.74, 0.68, and 0.72 in the training, validation, and entire cohorts, respectively. The sensitivity and specificity of the diagnosis model were 0.8698 and 0.9722, respectively. In addition, the prognosis model was also significantly correlated with several immune cells and factors.

Conclusion

Our present study suggested that these five FI-DEGs (CCR4, CMTM3, IFITM1, MX2, and NR3C2) could be used as prognosis and diagnosis biomarkers for patients with KIRC, but further cross-validation clinical studies are still needed to confirm them.

Development and Validation of Ferroptosis- and Immune-Related lncRNAs Signatures for Breast Infiltrating Duct and Lobular Carcinoma

Background

Heterogeneity of breast cancer (BRCA) is significantly correlated with its prognosis. Target therapy for ferroptosis and immunity is a new cancer treatment option discovered in recent years. In the present study, we aimed to identify ferroptosis- and immune-related long non-coding RNAs (lncRNAs) to accurately predict the prognosis and diagnosis of patients with breast infiltrating duct and lobular carcinoma by integrated analyses.

Methods

The corresponding data for the patients with breast infiltrating duct and lobular carcinoma by integrated analyses were obtained from The Cancer Genome Atlas (TCGA). Analyses of univariate and multivariate Cox regressions were used to identify the suitable candidate biomarkers.

Results

We found that seven ferroptosis- and immune-related differentially expressed lncRNAs (FI-DELs) (AC007686.3, AC078883.1, ADAMTS9-AS1, AL035661.1, CBR3-AS1, FTX, and TMEM105) were correlated with the overall survival of patients with breast infiltrating duct and lobular carcinoma. The areas under the receiver operating characteristic (AUCs) value of the prognosis model were all over 0.6 in training, validation, and entire groups. The sensitivity and specificity of the diagnosis model was 87.84% and 97.06%, respectively.

Conclusions

Through a series of bioinformatics analyses, we found that the seven FI-DELs could serve as prognostic and diagnostic biomarkers for patients with breast infiltrating duct and lobular carcinoma. However, whether these seven biomarkers could be really applied to the clinic requires further investigations.

The Potential Role of Ferroptosis in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that is accompanied with autoantibody production and inflammation. Other features of SLE pathogenesis include iron accumulation, oxidative stress, and lipid peroxidation, which are also major biochemical characteristics of ferroptosis, a novel non-apoptotic regulated form of cell death. To date, ferroptosis has been demonstrated to be an important driver of lupus progression, and several ferroptosis inhibitors have therapeutic effect in lupus-prone mice. Given the emerging link between ferroptosis and SLE, it can be postulated that ferroptosis is an integral component in the vicious cycle of immune dysfunction, inflammation, and tissue damage in SLE pathogenesis. In this review, we summarize the potential links between ferroptosis and SLE, with the aim of elucidating the underlying pathogenic mechanism of ferroptosis in lupus, and providing a new promising therapeutic strategy for SLE.

Construction and Validation of a Ferroptosis-Related Prognostic Signature for Melanoma Based on Single-Cell RNA Sequencing

Melanoma, the deadliest type of skin cancer, is on the rise globally. The generally poor prognosis makes melanoma still an enormous public health problem. Ferroptosis is a newly emerging form of iron-dependent regulated cell death, which has been implicated in the development and treatment of several tumors. However, whether there is a connection between ferroptosis-related genes and the prognosis of melanoma patients remains an enigma. In the present study, we identified a ferroptosis-related genes signature to predict the prognosis of melanoma patients by analyzing single-cell RNA-sequencing data from the Gene Expression Omnibus (GEO). Single-cell trajectory analysis was performed to explore malignant differentiation. CellChat was used to investigate intercellular communications in melanoma. Collectively, a novel four-gene signature (CP, MAP1LC3A, transferrin, and TP53) was constructed for prognosis prediction. COX proportional hazards regression analysis showed that the established ferroptosis-associated risk model was an independent prognostic predictor for melanoma patients (HR = 2.3293; 95%CI 1.1528–4.706) (p < 0.018). Patients with low-risk scores had significantly better overall survival (OS) than those with high-risk scores in The Cancer Genome Atlas, GSE59455, and GSE22153 dataset (p = 0.0015, p = 0.031, p = 0.077). Furthermore, the gene expression level of the four genes were verified in multistrain melanoma cell lines and normal human epidermal melanocytes (NHEM). The protein expression level of the four genes in clinical samples were further verified in the Human Protein Atlas (HPA) databases. Taken together, our study identified the prognostic significance of the ferroptosis-related genes in melanoma and developed a novel four-gene prognostic signature, which may shed light on the prognostic assessment and clinical decision making for melanoma patients.

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

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

Increased Lipid Peroxidation May Be Linked to Ferritin Levels Elevation in Adult-Onset Still's Disease

Lipid peroxidation (LPO) and hyper-ferritinemia are involved in inflammatory responses. Although hyper-ferritinemia is a characteristic of AOSD, its link to LPO remains unclear. We investigated the association between LPO and ferritin expression, and evaluated the relationship between LPO-related metabolites and inflammatory parameters. Mean fluorescence intensity (MFI) of LPO (C11-Biodipy^581/591)-expressing PBMCs/monocytes in AOSD patients and healthy control (HC) subjects was determined by flow-cytometry analysis. Expression of ferritin and cytokines on PBMCs/macrophages was examined by immunoblotting. Plasma levels of LPO-related metabolites and cytokines were determined by ELISA and the MULTIPLEX platform, respectively. LPO MFI on PBMCs/monocytes were significantly higher in patients (median 4456 and 9091, respectively) compared with HC (1900, p < 0.05, and 4551, p < 0.01, respectively). Patients had higher ferritin expression on PBMCs (mean fold, 1.02) than HC (0.55, p < 0.05). Their ferritin expression levels on PBMCs stimulated with LPO inducers erastin or RSL3 (2.47 or 1.61, respectively) were higher than HC (0.84, p < 0.05, or 0.74, p < 0.01). Ferritin expression on erastin-treated/IL-1β-treated macrophages from patients were higher than those from HC (p < 0.001). The elevated levels of LPO-related metabolites, including malondialdehyde and 4-hydroxyalkenals, were positively correlated with disease activity scores, suggesting LPO involvement in AOSD pathogenesis. Increased ferritin expression on PBMCs/macrophages stimulated with LPO inducers indicates a link between LPO and elevated ferritin.

Programmed cell death in aortic aneurysm and dissection: A potential therapeutic target

Rupture of aortic aneurysm and dissection (AAD) remains a leading cause of death. Progressive smooth muscle cell (SMC) loss is a crucial feature of AAD that contributes to aortic dysfunction and degeneration, leading to aortic aneurysm, dissection, and, ultimately, rupture. Understanding the molecular mechanisms of SMC loss and identifying pathways that promote SMC death in AAD are critical for developing an effective pharmacologic therapy to prevent aortic destruction and disease progression. Cell death is controlled by programmed cell death pathways, including apoptosis, necroptosis, pyroptosis, and ferroptosis. Although these pathways share common stimuli and triggers, each type of programmed cell death has unique features and activation pathways. A growing body of evidence supports a critical role for programmed cell death in the pathogenesis of AAD, and inhibitors of various types of programmed cell death represent a promising therapeutic strategy. This review discusses the different types of programmed cell death pathways and their features, induction, contributions to AAD development, and therapeutic potential. We also highlight the clinical significance of programmed cell death for further studies.

Ferroptosis in infection, inflammation, and immunity

Ferroptosis is a type of regulated necrosis that is triggered by a combination of iron toxicity, lipid peroxidation, and plasma membrane damage. The upstream inducers of ferroptosis can be divided into two categories (biological versus chemical) and activate two major pathways (the extrinsic/transporter versus the intrinsic/enzymatic pathways). Excessive or deficient ferroptotic cell death is implicated in a growing list of physiological and pathophysiological processes, coupled to a dysregulated immune response. This review focuses on new discoveries related to how ferroptotic cells and their spilled contents shape innate and adaptive immunity in health and disease. Understanding the immunological characteristics and activity of ferroptotic death not only illuminates an intersection between cell death and immunity but may also lead to the development of novel treatment approaches for immunopathological diseases.

Identification the ferroptosis-related gene signature in patients with esophageal adenocarcinoma

BACKGROUND

Ferroptosis is a recently recognized non-apoptotic cell death that is distinct from the apoptosis, necroptosis and pyroptosis. Considerable studies have demonstrated ferroptosis is involved in the biological process of various cancers. However, the role of ferroptosis in esophageal adenocarcinoma (EAC) remains unclear. This study aims to explore the ferroptosis-related genes (FRG) expression profiles and their prognostic values in EAC.

METHODS

The FRG data and clinical information were downloaded from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate cox regressions were used to identify the prognostic FRG, and the predictive ROC model was established using the independent risk factors. GO and KEGG enrichment analyses were performed to investigate the bioinformatics functions of significantly different genes (SDG) of ferroptosis. Additionally, the correlations of ferroptosis and immune cells were assessed through the single-sample gene set enrichment analysis (ssGSEA) and TIMER database. Finally, SDG were verified in clinical EAC specimens and normal esophageal mucosal tissues.

RESULTS

Twenty-eight significantly different FRG were screened from 78 EAC and 9 normal tissues. Enrichment analyses showed these SDG were mainly related to the iron-related pathways and metabolisms of ferroptosis. Gene network demonstrated the TP53, G6PD, NFE2L2 and PTGS2 were the hub genes in the biology of ferroptosis. Cox regression analyses demonstrated four FRG (CARS1, GCLM, GLS2 and EMC2) had prognostic values for overall survival (OS) (all P < 0.05). ROC curve showed better predictive ability using the risk score (AUC = 0.744). Immune cell enrichment analysis demonstrated that the types of immune cells and their expression levels in the high-risk group were significant different with those in the low-risk group (all P < 0.05). The experimental results confirmed the ALOX5, NOX1 were upregulated and the MT1G was downregulated in the EAC tissues compared with the normal esophageal mucosal tissues (all P < 0.05).

CONCLUSIONS

We identified differently expressed ferroptosis-related genes that may involve in EAC. These genes have significant values in predicting the patients' OS and targeting ferroptosis may be an alternative for therapy. Further studies are necessary to verify these results of our study.

Ferroptosis: molecular mechanisms and health implications

Cell death can be executed through different subroutines. Since the description of ferroptosis as an iron-dependent form of non-apoptotic cell death in 2012, there has been mounting interest in the process and function of ferroptosis. Ferroptosis can occur through two major pathways, the extrinsic or transporter-dependent pathway and the intrinsic or enzyme-regulated pathway. Ferroptosis is caused by a redox imbalance between the production of oxidants and antioxidants, which is driven by the abnormal expression and activity of multiple redox-active enzymes that produce or detoxify free radicals and lipid oxidation products. Accordingly, ferroptosis is precisely regulated at multiple levels, including epigenetic, transcriptional, posttranscriptional and posttranslational layers. The transcription factor NFE2L2 plays a central role in upregulating anti-ferroptotic defense, whereas selective autophagy may promote ferroptotic death. Here, we review current knowledge on the integrated molecular machinery of ferroptosis and describe how dysregulated ferroptosis is involved in cancer, neurodegeneration, tissue injury, inflammation, and infection.

Abnormal Ferroptosis in Myelodysplastic Syndrome

Background

Ferroptosis is a form of iron-dependent non-apoptotic cell death, with characteristics of loss of the activity of the lipid repair enzyme, glutathione (GSH) peroxidase 4 (GPX4), and accumulation of lethal reactive lipid oxygen species. The mechanism of ferroptosis in myelodysplastic syndrome (MDS) is unclear.

Methods

Cell viability assay, reactive oxygen species (ROS) assay, GSH assay, and GPX activity assay were performed to study the regulation of ferroptosis in MDS cells obtained from MDS patients, the iron overload model mice, and cell lines.

Results

The growth-inhibitory effect of decitabine could be partially reversed by ferrostatin-1 and iron-chelating agent [desferrioxamine (DFO)] in MDS cell lines. Erastin could increase the cytotoxicity of decitabine on MDS cells. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in MDS cells upon treatment with decitabine, which could be reversed by ferrostatin-1. The concentration of hemoglobin in peripheral blood of iron overload mice was negatively correlated with intracellular Fe²⁺ level and ferritin concentration. Iron overload (IO) led to decreased viability of bone marrow mononuclear cells (BMMNCs), which was negatively correlated with intracellular Fe²⁺ level. Ferrostatin-1 partially reversed the decline of cell viability in IO groups. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in BMMNCs of IO mice. DFO could increase the level of GSH. Ferrostatin-1 and DFO could increase the GPX4 activity of BMMNCs in IO mice. Ferrostatin-1 could significantly reverse the growth-inhibitory effect of decitabine in MDS patients. Decitabine could significantly increase the ROS level in MDS groups, which could be inhibited by ferrostatin-1 or promoted by erastin. Ferrostatin-1 could significantly reverse the inhibitory effect of decitabine on GSH levels in MDS patients. Erastin combined with decitabine could further reduce the GSH level. Erastin could further decrease the activity of GPX4 compared with the decitabine group.

Conclusion

Ferroptosis may account for the main mechanisms of how decitabine induced death of MDS cells. Decitabine-induced ROS raise leads to ferroptosis in MDS cells by decreasing GSH level and GPX4 activity.

Targeting chronic lymphocytic leukemia with N-methylated thrombospondin-1-derived peptides overcomes drug resistance

Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia in Western countries, is a very heterogeneous disease characterized by a peripheral accumulation of abnormal CD5+ B lymphocytes in the immune system. Despite new therapeutic developments, there remains an unmet medical need for CLL. Here, we demonstrate that the use of N-methylated thrombospondin-1 (TSP-1)-derived peptides is an efficient way to kill the malignant CLL cells, including those from high-risk individuals with poor clinical prognosis, del11q, del17p, 2p gain, or complex karyotype. PKT16, our hit N-methylated peptide, triggers the elimination of the leukemic cells, sparing the nontumor cells, including the hematopoietic precursors, and reduces the in vivo tumor burden of a CLL-xenograft mice model. A complementary analysis underscores the improved cytotoxic efficiency of PKT16 compared with the previously described TSP-1-derived probes, such as PKHB1. PKT16 elicits an original caspase-independent programmed necrotic mode of cell death, different from necroptosis or ferroptosis, implicating an intracellular Ca2+ deregulation that provokes mitochondrial damage, cell cycle arrest, and the specific death of the malignant CLL cells. The activation of the Gαi proteins and the subsequent drop of cyclic adenosine monophosphate levels and protein kinase A activity regulate this cytotoxic cascade. Remarkably, PKT16 induces the molecular hallmarks of immunogenic cell death, as defined by the calreticulin plasma membrane exposure and the release of adenosine triphosphate and high-mobility group box 1 protein from the dying CLL cells. Thus, PKT16 appears to be able to stimulate an anticancer in vivo immune response. Collectively, our results pave the way toward the development of an efficient strategy against CLL.

Active steroid hormone synthesis renders adrenocortical cells highly susceptible to type II ferroptosis induction

Conditions of impaired adrenal function and tissue destruction, such as in Addison’s disease, and treatment resistance of adrenocortical carcinoma (ACC) necessitate improved understanding of the pathophysiology of adrenal cell death. Due to relevant oxidative processes in the adrenal cortex, our study investigated the role of ferroptosis, an iron-dependent cell death mechanism and found high adrenocortical expression of glutathione peroxidase 4 (GPX4) and long-chain-fatty-acid CoA ligase 4 (ACSL4) genes, key factors in the initiation of ferroptosis. By applying MALDI mass spectrometry imaging to normal and neoplastic adrenocortical tissue, we detected high abundance of arachidonic and adrenic acid, two long chain polyunsaturated fatty acids which undergo peroxidation during ferroptosis. In three available adrenal cortex cell models (H295R, CU-ACC1 and CU-ACC-2) a high susceptibility to GPX4 inhibition with RSL3 was documented with EC₅₀ values of 5.7 × 10⁻⁸, 8.1 × 10⁻⁷ and 2.1 × 10⁻⁸ M, respectively, while all non-steroidogenic cells were significantly less sensitive. Complete block of GPX4 activity by RSL3 led to ferroptosis which was completely reversed in adrenal cortex cells by inhibition of steroidogenesis with ketoconazole but not by blocking the final step of cortisol synthesis with metyrapone. Mitotane, the only approved drug for ACC did not induce ferroptosis, despite strong induction of lipid peroxidation in ACC cells. Together, this report is the first to demonstrate extraordinary sensitivity of adrenal cortex cells to ferroptosis dependent on their active steroid synthetic pathways. Mitotane does not induce this form of cell death in ACC cells.

Erastin Inhibits Septic Shock and Inflammatory Gene Expression via Suppression of the NF-κB Pathway

Sepsis is a life-threatening condition that is caused by an abnormal immune response to infection and can lead to tissue damage, organ failure, and death. Erastin is a small molecule capable of initiating ferroptotic cell death in cancer cells. However, the function of erastin in the inflammatory response during sepsis remains unknown. Here, we showed that erastin ameliorates septic shock induced by cecal ligation and puncture or lipopolysaccharides (LPS) in mice, which was associated with a reduced production of inflammatory mediators such as nitric oxide, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Pretreatment with erastin in bone marrow-derived macrophages (BMDMs) significantly attenuated the expression of inducible nitric oxide synthase, cyclooxygenase-2, TNF-α, and IL-1β mRNA in response to LPS treatment. Furthermore, we also showed that erastin suppresses phosphorylation of IκB kinase β, phosphorylation and degradation of IκBα, and nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in LPS-stimulated BMDMs. Our findings suggest that erastin attenuates the inflammatory response by suppressing the NF-κB signaling pathway, resulting in inhibition of sepsis development. This study provides new insights regarding the potential therapeutic properties of erastin in sepsis.

PM2.5 induces ferroptosis in human endothelial cells through iron overload and redox imbalance

PM2.5 is becoming a worldwide environmental problem, which profoundly endangers public health, thus progressively capturing public attention this decade. As a fragile target of PM2.5, the underlying mechanisms of endothelial cell damage are still obscure. According to the previous microarray data and signaling pathway analysis, a new form of cell death termed ferroptosis in the current study is proposed following PM2.5 exposure. In order to verify the vital role of ferroptosis in PM2.5-induced endothelial lesion and further understand the potential mechanism involved, intracellular iron content, ROS release and lipid peroxidation, as well as biomarkers of ferroptosis were detected, respectively. As a result, uptake of particles increases cellular iron content and ROS production. Meanwhile, GSH depletion, and the decrease of GSH-Px and NADPH play significant roles in PM2.5-induced endothelial cell ferroptosis. Moreover, significantly changed expression of TFRC, FTL and FTH1 hinted that dysfunction of iron uptake and storage is a major inducer of ferroptosis. Importantly, index monitored above can be partially rescued by lipid peroxidation inhibitor ferrostatin-1 and iron chelator deferoxamine mesylate, which mediated antiferroptosis activity mainly depends on the restoration of antioxidant activity and iron metabolism. In conclusion, our data basically show that PM2.5 enhances ferroptosis sensitivity with increased ferroptotic events in endothelial cells, in which iron overload, lipid peroxidation and redox imbalance act pivotal roles.

Ferroptosis is a type of autophagy-dependent cell death

Macroautophagy (hereafter referred to as autophagy) involves an intracellular degradation and recycling system that, in a context-dependent manner, can either promote cell survival or accelerate cellular demise. Ferroptosis was originally defined in 2012 as an iron-dependent form of cancer cell death different from apoptosis, necrosis, and autophagy. However, this latter assumption came into question because, in response to ferroptosis activators (e.g., erastin and RSL3), autophagosomes accumulate, and because components of the autophagy machinery (e.g., ATG3, ATG5, ATG4B, ATG7, ATG13, and BECN1) contribute to ferroptotic cell death. In particular, NCOA4-facilitated ferritinophagy, RAB7A-dependent lipophagy, BECN1-mediated system x_c^- inhibition, STAT3-induced lysosomal membrane permeabilization, and HSP90-associated chaperone-mediated autophagy can promote ferroptosis. In this review, we summarize current knowledge on the signaling pathways involved in ferroptosis, while focusing on the regulation of autophagy-dependent ferroptotic cell death. The molecular comprehension of these phenomena may lead to the development of novel anticancer therapies.