Ferroptosis in sepsis: The mechanism, the role and the therapeutic potential

Intravenous calcitriol administration improves the liver redox status and attenuates ferroptosis in mice with high-fat diet-induced obesity complicated with sepsis

Obesity aggravates ferroptosis, and vitamin D (VD) may inhibit ferroptosis. We hypothesized that weight reduction and/or calcitriol administration have benefits against the sepsis-induced liver redox imbalance and ferroptosis in obese mice. Mice were fed a high-fat diet for 11 weeks, then half of the mice continued to consume the diet, while the other half were transferred to a low-energy diet for 5 weeks. After feeding the respective diets for 16 weeks, sepsis was induced by cecal ligation and puncture (CLP). Septic mice were divided into four experimental groups: OS group, obese mice injected with saline; OD group, obese mice with calcitriol; WS group, weight-reduction mice with saline; and WD group, weight-reduction mice with calcitriol. Mice in the respective groups were euthanized at 12 or 24 h after CLP. Results showed that the OS group had the highest inflammatory mediators and lipid peroxide levels in the liver. Calcitriol treatment reduced iron content, enhanced the reduced glutathione/oxidized glutathione ratio, upregulated nuclear factor erythroid 2-related factor 2, ferroptosis-suppressing protein 1, and solute carrier family 7 member 11 expression levels. Also, mitochondrion-associated nicotinamide adenine dinucleotide phosphate oxidase 1, peroxisome proliferator-activated receptor-γ coactivator 1, hypoxia-inducible factor-1α, and heme oxidase-1 expression levels increased in the late phase of sepsis. These results were not noted in the WS group. These findings suggest that calcitriol treatment elicits a more-balanced glutathione redox status, alleviates liver ferroptosis, and enhances mitochondrial biogenesis-associated gene expressions. Weight reduction alone had minimal influences on liver ferroptosis and mitochondrial biogenesis in obese mice with sepsis.

Evaluating the Causal Effects of Circulating Proteome on the Risk of Sepsis and Related Outcomes

The current investigation deployed Mendelian randomization (MR) to elucidate the causal relationship between circulating proteins and sepsis. A rigorous two-sample MR analysis evaluated the effect of plasma proteins on the sepsis susceptibility. To affirm the integrity of MR findings, a suite of supplementary analyses, including Bayesian colocalization, Steiger filtering, the assessment of protein-altering polymorphisms, and the correlation between expression quantitative trait loci and protein quantitative trait loci (pQTLs), was employed. The study further integrated the examination of protein-protein interactions and pathway enrichment, along with the identification of pharmacologically actionable targets, to advance our comprehension and outline potential sepsis therapies. Subsequent analyses leveraging cis-pQTLs within MR studies unveiled noteworthy relationships: 94 specific proteins exhibited significant links with sepsis-related 28 day mortality, while 96 distinct proteins correlated with survival outcomes in sepsis. Furthermore, incorporating both cis- and trans-pQTLs in MR investigations revealed more comprehensive findings, associating 201 unique proteins with sepsis-related 28 day mortality and 199 distinct proteins with survival outcomes in sepsis. Markedly, colocalization analyses confirmed that eight of these proteins exhibited prominent evidence for colocalization, emphasizing their potential criticality in sepsis pathophysiology. Further in silico analyses were conducted to delineate putative regulatory networks and to highlight prospective drug targets among these proteins. Employing the MR methodology has shed light on plasma proteins implicated in the etiopathogenesis of sepsis. This novel approach unveiled numerous biomarkers and targets, providing a scientific rationale for the development of new therapeutic strategies and prophylactic measures against sepsis.

Dysregulated dendritic cells in sepsis: functional impairment and regulated cell death

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Studies have indicated that immune dysfunction plays a central role in the pathogenesis of sepsis. Dendritic cells (DCs) play a crucial role in the emergence of immune dysfunction in sepsis. The major manifestations of DCs in the septic state are abnormal functions and depletion in numbers, which are linked to higher mortality and vulnerability to secondary infections in sepsis. Apoptosis is the most widely studied pathway of number reduction in DCs. In the past few years, there has been a surge in studies focusing on regulated cell death (RCD). This emerging field encompasses various forms of cell death, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death (ADCD). Regulation of DC's RCD can serve as a possible therapeutic focus for the treatment of sepsis. Throughout time, numerous tactics have been devised and effectively implemented to improve abnormal immune response during sepsis progression, including modifying the functions of DCs and inhibiting DC cell death. In this review, we provide an overview of the functional impairment and RCD of DCs in septic states. Also, we highlight recent advances in targeting DCs to regulate host immune response following septic challenge.

Targeting novel regulated cell death：Ferroptosis, pyroptosis, and autophagy in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE), a common neurological complication of sepsis, is a heterogenous complex clinical syndrome caused by the dysfunctional response of a host to infection. This dysfunctional response leads to excess mortality and morbidity worldwide. Despite clinical relevance with high incidence, there is a lack of understanding for its both its acute/chronic pathogenesis and therapeutic management. A better understanding of the molecular mechanisms behind SAE may provide tools to better enhance therapeutic efficacy. Mounting evidence indicates that some types of non-apoptotic regulated cell death (RCD), such as ferroptosis, pyroptosis, and autophagy, contribute to SAE. Targeting these types of RCD may provide meaningful targets for future treatments against SAE. This review summarizes the core mechanism by which non-apoptotic RCD leads to the pathogenesis of SAE. We focus on the emerging types of therapeutic compounds that can inhibit RCD and delineate their beneficial pharmacological effects against SAE. Within this review we suggest that pharmacological inhibition of non-apoptotic RCD may serve as a potential therapeutic strategy against SAE.

GPX4, ferroptosis, and diseases

GPX4 (Glutathione peroxidase 4) serves as a crucial intracellular regulatory factor, participating in various physiological processes and playing a significant role in maintaining the redox homeostasis within the body. Ferroptosis, a form of iron-dependent non-apoptotic cell death, has gained considerable attention in recent years due to its involvement in multiple pathological processes. GPX4 is closely associated with ferroptosis and functions as the primary inhibitor of this process. Together, GPX4 and ferroptosis contribute to the pathophysiology of several diseases, including sepsis, nervous system diseases, ischemia reperfusion injury, cardiovascular diseases, and cancer. This review comprehensively explores the regulatory roles and impacts of GPX4 and ferroptosis in the development and progression of these diseases, with the aim of providing insights for identifying potential therapeutic strategies in the future.

Identification of ferroptosis-associated genes and potential pharmacological targets in sepsis-induced myopathy

Background

The role of Ferroptosis in the course of sepsis-induced myopathy is yet unclear. The objective of our work is to identify key genes connected with Ferroptosis in sepsis-induced myopathy and investigate possible pharmaceutical targets related to this process. This research aims to provide new insights into the management of sepsis-induced myopathy.

Methods

We got the GSE13205 dataset from the Gene Expression Omnibus (GEO) and extracted Ferroptosis-associated genes from the FerrDb database. After conducting a functional annotation analysis of these genes, we created a protein-protein interaction network using Cytoscape software to identify important genes. Subsequently, we employed CMap to investigate prospective pharmaceuticals that could target these crucial genes.

Results

A total of 61 genes that are expressed differently (DEGs) have been found concerning Ferroptosis. These genes are involved in a wide range of biological functions, including reacting to signals from outside the cell and the availability of nutrients, programmed cell death, controlling apoptosis, and responding to peptides, chemical stressors, and hormones. The KEGG pathway study revealed that these pathways are involved in Ferroptosis, autophagy, P53 signaling, PI3K-Akt signaling, mTOR signaling, HIF-1 signaling, endocrine resistance, and different tumorigenic processes. In addition, we created a network that shows the simultaneous expression of important genes and determined the top 10 medications that have the potential to treat sepsis-induced myopathy.

Conclusion

The bioinformatics research undertaken sheds insight into the probable role of Ferroptosis-associated genes in sepsis-induced myopathy. The identified critical genes show potential as therapeutic targets for treating sepsis-induced myopathy, offering opportunities for the development of tailored medicines.

Emerging mechanisms of ferroptosis and its implications in lung cancer

ABSTRACT

Lung cancer is one of the most common malignancies and has the highest number of deaths among all cancers. Despite continuous advances in medical strategies, the overall survival of lung cancer patients is still low, probably due to disease progression or drug resistance. Ferroptosis is an iron-dependent form of regulated cell death triggered by the lethal accumulation of lipid peroxides, and its dysregulation is implicated in cancer development. Preclinical evidence has shown that targeting the ferroptosis pathway could be a potential strategy for improving lung cancer treatment outcomes. In this review, we summarize the underlying mechanisms and regulatory networks of ferroptosis in lung cancer and highlight ferroptosis-targeting preclinical attempts to provide new insights for lung cancer treatment.

The possible mechanisms of ferroptosis in sepsis-associated acquired weakness

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, and its morbidity and mortality rates are increasing annually. It is an independent risk factor for intensive care unit-acquired weakness (ICU-AW), which is a common complication of patients in ICU. This situation is also known as sepsis-associated acquired weakness (SAW), and it can be a complication in more than 60% of patients with sepsis. The outcomes of SAW are often prolonged mechanical ventilation, extended hospital stays, and increased morbidity and mortality of patients in ICUs. The pathogenesis of SAW is unclear, and an effective clinical treatment is not available. Ferroptosis is an iron-dependent type of cell death with unique morphological, biochemical, and genetic features. Unlike other forms of cell death such as autophagy, apoptosis, and necrosis, ferroptosis is primarily driven by lipid peroxidation. Cells undergo ferroptosis during sepsis, which further enhances the inflammatory response. This process leads to increased cell death, as well as multi-organ dysfunction and failure. Recently, there have been sporadic reports suggesting that SAW is associated with ferroptosis, but the exact pathophysiological mechanisms remain unclear. Therefore, we reviewed the possible pathogenesis of ferroptosis that leads to SAW and offer new strategies to prevent and treat SAW.

Differential mRNA profiles reveal the potential roles of genes involved in lactate stimulation in mouse macrophages

Lactate is a glycolysis end product, and its levels are markedly associated with disease severity, morbidity, and mortality in sepsis. It modulates key functions of immune cells, including macrophages. In this investigation, transcriptomic analysis was performed using lactic acid, sodium lactate, and hydrochloric acid-stimulated mouse bone marrow-derived macrophages (iBMDM), respectively, to identify lactate-associated signaling pathways. After 24 h of stimulation, 896 differentially expressed genes (DEG) indicated were up-regulation, whereas 792 were down-regulated in the lactic acid group, in the sodium lactate group, 128 DEG were up-regulated, and 41 were down-regulated, and in the hydrochloric acid group, 499 DEG were up-regulated, and 285 were down-regulated. Subsequently, clinical samples were used to further verify the eight genes with significant differences, among which Tssk6, Ypel4, Elovl3, Trp53inp1, and Cfp were differentially expressed in patients with high lactic acid, indicating their possible involvement in lactic acid-induced inflammation and various physiological diseases caused by sepsis. However, elongation of very long chain fatty acids protein 3 (Elovl3) was negatively correlated with lactic acid content in patients. The results of this study provide a necessary reference for better understanding the transcriptomic changes caused by lactic acid and explain the potential role of high lactic acid in the regulation of macrophages in sepsis.

Metallothionein Alleviates Glutathione Depletion-Induced Oxidative Cardiomyopathy through CISD1-Dependent Regulation of Ferroptosis in Murine Hearts

This study was designed to discern the effect of heavy scavenger metallothionein on glutathione (GSH) deprivation-evoked cardiac anomalies and mechanisms involved with an emphasis on ferroptosis. Wild-type and cardiac metallothionein transgenic mice received GSH synthase inhibitor buthionine sulfoximine (BSO; 30 mmol/L in drinking water) for 14 days before assessment of myocardial morphology and function. BSO evoked cardiac remodeling and contractile anomalies, including cardiac hypertrophy, interstitial fibrosis, enlarged left ventricular chambers, deranged ejection fraction, fraction shortening, cardiomyocyte contractile capacity, intracellular Ca2+ handling, sarcoplasmic reticulum Ca2+ reuptake, loss of mitochondrial integrity (mitochondrial swelling, loss of aconitase activity), mitochondrial energy deficit, carbonyl damage, lipid peroxidation, ferroptosis, and apoptosis. Metallothionein itself did not affect myocardial morphology and function, although it mitigated BSO-provoked myocardial anomalies, loss of mitochondrial integrity and energy, and ferroptosis. Immunoblotting revealed down-regulated sarco(endo)plasmic reticulum Ca2+-ATPase 2a, glutathione peroxidase 4, the ferroptosis-suppressing iron-sulfur domain 1 (CISD1), and mitochondrial regulating glycogen synthase kinase-3β phosphorylation with elevated p53, myosin heavy chain-β isozyme, IκB phosphorylation, and SLC7A11 as well as unchanged SLC39A1, SLC1A5, and ferroptosis-suppressing protein 1 following BSO challenge, all of which, except glutamine transporter SLC7A11 and p53, were abrogated by metallothionein. Inhibition of CISD1 using pioglitazone nullified GSH-offered benefit against BSO-induced cardiomyocyte ferroptosis and contractile and intracellular Ca2+ derangement. Taken together, these findings support a regulatory modality for CISD1 in the impedance of ferroptosis in metallothionein-offered protection against GSH depletion-evoked cardiac aberration.

Targeting ferroptosis in the maintenance of mitochondrial homeostasis in the realm of septic cardiomyopathy

Septic cardiomyopathy is one of the predominant culprit factors contributing to the rising mortality in patients with severe sepsis. Among various mechanisms responsible for the etiology of septic heart anomalies, disruption of mitochondrial homeostasis has gained much recent attention, resulting in myocardial inflammation and even cell death. Ferroptosis is a novel category of regulated cell death (RCD) provoked by iron-dependent phospholipid peroxidation through iron-mediated phospholipid (PL) peroxidation, enroute to the rupture of plasma membranes and eventually cell death. This review summarizes the recent progress of ferroptosis in mitochondrial homeostasis during septic cardiomyopathy. We will emphasize the role of mitochondrial iron transport channels and the antioxidant system in ferroptosis. Finally, we will summarize and discuss future research, which should help guide disease treatment.

Involvement of CD44 and MAPK14-mediated ferroptosis in hemorrhagic shock

To elucidate the induction of ferroptotic pathways and the transcriptional modulation of pivotal genes in the context of hemorrhagic shock. The R software was used to analyze the GSE64711 dataset, isolating genes relevant to ferroptosis. Enrichment analyses and protein interaction networks were assembled. Using WGCNA hub genes were identified and intersected with ferroptosis-related genes, highlighting hub genes CD44 and MAPK14. In a rat hemorrhagic shock model, cardiac ROS, Fe2+, MDA, and GSH levels were assessed. Key ferroptotic proteins (SLC7A11/GPX4) in myocardial tissues were examined via western blot. Hub genes, CD44 and MAPK14, expressions were confirmed through immunohistochemistry. Analyzing the GSE64711 dataset revealed 337 differentially expressed genes, including 12 linked to ferroptosis. Enrichment analysis highlighted pathways closely related to ferroptosis. Using Genemania, we found these genes mainly affect ROS metabolism and oxidative stress response. WGCNA identified CD44 and MAPK14 as hub genes. Rat myocardial tissue validation showed significant cardiac damage and elevated ROS and MDA levels, and decreased GSH levels in the hemorrhagic shock model. The ferroptotic pathway SLC7A11/GPX4 was activated, and immunohistochemistry showed a significant increase in the expression levels of CD44 and MAPK14 in the hemorrhagic shock rat model. We demonstrated the presence of tissue ferroptosis in hemorrhagic shock by combining bioinformatics analysis with in vivo experimentation. Specifically, we observed the activation of the SLC7A11/GPX4 ferroptotic pathway. Further, CD44 and MAPK14 were identified as hub genes in hemorrhagic shock.

STAT3-Mediated Ferroptosis is Involved in Sepsis-Associated Acute Respiratory Distress Syndrome

Sepsis-induced acute respiratory distress syndrome (ARDS) poses a grave danger to life, resulting from sepsis-induced multi-organ failure. Although ferroptosis, a form of iron-dependent lipid peroxidative cell death, has been associated with sepsis-induced ARDS, the specific mechanisms are not fully understood. In this study, we utilized WGCNA, PPI, friends analysis, and six machine learning techniques (Lasso, SVM, RFB, XGBoost, AdaBoost, and LightGBM) to pinpoint STAT3 as a potential diagnostic marker. A significant increase in monocyte and neutrophil levels was observed in patients with sepsis-induced ARDS, as revealed by immune infiltration analyses, when compared to controls. Moreover, there was a positive correlation between STAT3 expression and the level of infiltration. Single-cell analysis uncovered a notable disparity in B-cell expression between sepsis and sepsis-induced ARDS. Furthermore, in vitro experiments using LPS-treated human bronchial epithelial cells (BEAS-2B) and THP1 cells demonstrated a significant increase in STAT3 phosphorylation expression. Additionally, the inhibition of STAT3 phosphorylation by Stattic effectively prevented LPS-induced ferroptosis in both BEAS-2B and THP1 cells. This indicates that the activation of STAT3 phosphorylation promotes ferroptosis in human bronchial epithelial cells in response to LPS. In summary, this research has discovered and confirmed STAT3 as a potential biomarker for the diagnosis and treatment of sepsis-induced ARDS.

Bioinformatics reveals diagnostic potential of cuproptosis-related genes in the pathogenesis of sepsis

Background

Multiple modes of cell death occur during the development of sepsis. Among these patterns, cuproptosis has recently been identified as a regulated form of cell death. However, its impact on the onset and progression of sepsis remains unclear.

Method

We screened a dataset of gene expression profiles from patients with sepsis using the GEO database. Survival analysis was performed to analyze the relationship between cuproptosis-related genes (CRGs) and prognosis. Hub genes were identified through univariate Cox regression analysis. The diagnostic value of hub genes in sepsis was tested in both training sets (GSE65682) and validation sets (GSE134347). To examine the association between hub genes and immune cells, single-sample gene set enrichment analysis (ssGSEA) and Pearson correlation analysis were employed. Additionally, the CRGs were validated in a septic mouse model using real-time quantitative PCR (qRT-PCR) and immunohistochemistry (IHC).

Results

In sepsis, most CRGs were upregulated, with only DLD and MTF1 downregulated. High expression of three genes (GLE, LIAS, and PDHB) was associated with better prognosis, but only two hub genes (LIAS, PDHB) reached statistical significance. The receiver operating characteristic (ROC) analysis for diagnosing sepsis showed LIAS had a range of 0.793-0.906, while PDHB achieved values of 0.882 and 0.975 in the training and validation sets, respectively. ssGSEA analysis revealed a lower number of immune cells in the sepsis group, and there was a correlation between immune cell population and CRGs (LIAS, PDHB). Analysis in the septic mouse model demonstrated no significant difference in mRNA expression levels and IHC staining between LIAS and PDHB in heart and liver tissues, but up-regulation was observed in lung tissues. Furthermore, the mRNA expression levels and IHC staining of LIAS and PDHB were down-regulated in renal tissues.

Conclusions

Cuproptosis is emerging as a significant factor in the development of sepsis. LIAS and PDHB, identified as potential diagnostic biomarkers for cuproptosis-associated sepsis, are believed to play crucial roles in the initiation and progression of cuproptosis-induced sepsis.

Exploring the efficacious constituents and underlying mechanisms of sini decoction for sepsis treatment through network pharmacology and multi-omics

BACKGROUND

Traditional Chinese medicine prescription sini decoction (SND) can alleviate inflammation, improve microcirculation, and modulate immune status in sepsis patients. However, its underlying mechanisms remain unclear, and therapeutic effects may vary among individuals.

PURPOSE

Through a comprehensive and systematic network pharmacology analysis, the purpose of this study is to investigate the therapeutic mechanisms of SND in treating sepsis.

METHODS

An analysis of WGCNA identified CX3CR1 as a key gene influencing sepsis prognosis. A drug-active component-target network for SND was created using the traditional Chinese medicine systems pharmacology (TCMSP) database and Cytoscape software. Shared targets between SND and CX3CR1 high-expression gene modules were found through the GEO database. Gene module functionality was analyzed using GO, KEGG, GSEA, and GSVA. Unsupervised clustering of sepsis patients was performed based on the ferroptosis gene set, and immune cell interactions and mechanisms were explored using CIBERSORT, single-cell sequencing, and intercellular communication analysis.

RESULTS

This study demonstrates that high expression of CX3CR1 improves survival rates in sepsis patients and is associated with immune cell signaling pathways. SND contains 116 active components involved in oxidative stress and lipid metabolism pathways. HMOX1, a co-expressed gene in SND and CX3CR1 high-expression gene module, plays a crucial role in sepsis survival. Unsupervised clustering analysis classified sepsis patients into three clusters based on the ferroptosis gene set, revealing differences in immune cell expression and involvement in heme metabolism pathways. Notably, intercellular interactions among immune cells primarily occur through paracrine and autocrine mechanisms in MIF, GALECTIN, and IL16 signaling pathways, modulating the immune-inflammatory microenvironment in sepsis.

CONCLUSIONS

This study identifies CX3CR1 as a crucial molecule impacting sepsis prognosis through WGCNA analysis. It reveals that SND's active component, quercetin and kaempferol, target HMOX1 via related pathways to regulate heme metabolism, reduce inflammation, inhibit ferroptosis, and improve immune function, ultimately improving sepsis prognosis. These findings offer a solid pharmacological foundation and potential therapeutic targets for SND in treating sepsis.

Role of YAP Signaling in Regulation of Programmed Cell Death and Drug Resistance in Cancer

Although recent advances in cancer treatment significantly improved the prognosis of patients, drug resistance remains a major challenge. Targeting programmed cell death is a major approach of antitumor drug development. Deregulation of programmed cell death (PCD) contributes to resistance to a variety of cancer therapeutics. Yes-associated protein (YAP) and its paralog TAZ, the main downstream effectors of the Hippo pathway, are aberrantly activated in a variety of human malignancies. The Hippo-YAP pathway, which was originally identified in Drosophila, is well conserved in humans and plays a defining role in regulation of cell fate, tissue growth and regeneration. Activation of YAP signaling has emerged as a key mechanism involved in promoting cancer cell proliferation, metastasis, and drug resistance. Understanding the role of YAP/TAZ signaling network in PCD and drug resistance could facilitate the development of effective strategies for cancer therapeutics.

Klotho activation of Nrf2 inhibits the ferroptosis signaling pathway to ameliorate sepsis-associated acute kidney injury

Background

Sepsis-associated acute kidney injury (SA-AKI) is a common complication of sepsis and greatly increases patient mortality. Recombinant human Klotho protein (Klotho) is a protective protein that can be secreted by the kidney. The aim of this study was to explore the protective effect of Klotho on SA-AKI and its molecular mechanism.

Methods

In vivo, a mouse SA-AKI model was constructed by cecum ligation perforation (CLP). In vitro, a human renal tubular cell epithelial cell line (HK2) was induced with lipopolysaccharide (LPS) in the SA-AKI model. Determine renal injury markers, inflammatory factors, oxidative stress and molecular proteins related to the ferroptosis signaling pathway.

Results

Klotho reduced the release of renal injury markers and inflammatory cytokines, decreased oxidative stress, improved renal histopathological changes, ameliorated mitochondrial damage in mouse renal tubular epithelial cells, increased HK2 cell viability and reduced reactive oxygen species (ROS) accumulation. Exogenous supplementation with Klotho increased the Klotho content in circulating blood, renal tissue and HK2 cells.

Conclusions

In the SA-AKI model, Klotho attenuated renal tissue injury, increased HK2 cell viability, decreased inflammatory factor expression and oxidative stress, restored tubular epithelial mitochondrial function, and increased its level in circulating blood, renal tissue and HK2 cells. Klotho probably exerts its protective effects by activating Nrf2 to inhibit the ferroptosis signaling pathway.

Iron as an emerging therapeutic target in critically ill patients

The multiple roles of iron in the body have been known for decades, particularly its involvement in iron overload diseases such as hemochromatosis. More recently, compelling evidence has emerged regarding the critical role of non-transferrin bound iron (NTBI), also known as catalytic iron, in the care of critically ill patients in intensive care units (ICUs). These trace amounts of iron constitute a small percentage of the serum iron, yet they are heavily implicated in the exacerbation of diseases, primarily by catalyzing the formation of reactive oxygen species, which promote oxidative stress. Additionally, catalytic iron activates macrophages and facilitates the growth of pathogens. This review aims to shed light on this underappreciated phenomenon and explore the various common sources of NTBI in ICU patients, which lead to transient iron dysregulation during acute phases of disease. Iron serves as the linchpin of a vicious cycle in many ICU pathologies that are often multifactorial. The clinical evidence showing its detrimental impact on patient outcomes will be outlined in the major ICU pathologies. Finally, different therapeutic strategies will be reviewed, including the targeting of proteins involved in iron metabolism, conventional chelation therapy, and the combination of renal replacement therapy with chelation therapy.

The mechanism of ferroptosis and its related diseases

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

Ferroptosis: new insight into the mechanisms of diabetic nephropathy and retinopathy

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are the most serious and common diabetes-associated complications. DN and DR are all highly prevalent and dangerous global diseases, but the underlying mechanism remains to be elucidated. Ferroptosis, a relatively recently described type of cell death, has been confirmed to be involved in the occurrence and development of various diabetic complications. The disturbance of cellular iron metabolism directly triggers ferroptosis, and abnormal iron metabolism is closely related to diabetes. However, the molecular mechanism underlying the role of ferroptosis in DN and DR is still unclear, and needs further study. In this review article, we summarize and evaluate the mechanism of ferroptosis and its role and progress in DN and DR, it provides new ideas for the diagnosis and treatment of DN and DR.

GPX4 is a key ferroptosis biomarker and correlated with immune cell populations and immune checkpoints in childhood sepsis

Sepsis is the uncontrolled reaction of the body to infection-induced inflammation, which results in life-threatening multiple-organ dysfunction (MODS). Although the research on sepsis has advanced significantly in recent years, its pathophysiology remains entirely unknown. Ferroptosis is a new-fashioned type of programmed cell death that may have an impact on sepsis development. However, the precise mechanism still needs to be explored. In this paper, Four pediatric sepsis datasets [training datasets (GSE26378 and GSE26440) and validation datasets (GSE11755 and GSE11281)] were chosen through the GEO (Gene Expression Omnibus) database, and 63 differentially expressions of ferroptosis-relation-genes (DE-FRGs) were eventually discovered using bioinformatics investigation. Functional annotation was performed using GO and KEGG pathway enrichment analysis. Then, four Core-FRGs (FTH1, GPX4, ACSL1, and ACSL6) were extracted after the construction of the protein-protein interaction (PPI) network and the research of the MCODE module. Consequently, Hub-FRG (GPX4) was found using the validation datasets, and correlation exploration of immunity populations (neutrophils, r =  - 0.52; CD8 T-cells, r = 0.43) and immunity checkpoints (CD274, r =  - 0.42) was implemented. The usefulness of GPX4 as a marker in sepsis was assessed in a mouse model of sepsis. The findings demonstrate that GPX4 is a crucial biomarker and a new latent immunotherapy target for the prediction and therapy of pediatric sepsis.

The Road from AKI to CKD: Molecular Mechanisms and Therapeutic Targets of Ferroptosis

Acute kidney injury (AKI) is a prevalent pathological condition that is characterized by a precipitous decline in renal function. In recent years, a growing body of studies have demonstrated that renal maladaptation following AKI results in chronic kidney disease (CKD). Therefore, targeting the transition of AKI to CKD displays excellent therapeutic potential. However, the mechanism of AKI to CKD is mediated by multifactor, and there is still a lack of effective treatments. Ferroptosis, a novel nonapoptotic form of cell death, is believed to have a role in the AKI to CKD progression. In this study, we retrospectively examined the history and characteristics of ferroptosis, summarized ferroptosis's research progress in AKI and CKD, and discussed how ferroptosis participates in regulating the pathological mechanism in the progression of AKI to CKD. Furthermore, we highlighted the limitations of present research and projected the future evolution of ferroptosis. We hope this work will provide clues for further studies of ferroptosis in AKI to CKD and contribute to the study of effective therapeutic targets to prevent the progression of kidney diseases.

Wenqingyin suppresses ferroptosis in the pathogenesis of sepsis-induced liver injury by activating the Nrf2-mediated signaling pathway

BACKGROUND

Wenqingyin (WQY) is a classic traditional Chinese medicine formula used to treat various inflammatory diseases. However, its protective activity against ferroptosis in the pathogenesis of sepsis-induced liver injury and underlying mechanisms remain unclear.

PURPOSE

This study aimed to determine the therapeutic efficacy and potential mechanism of action of WQY in sepsis-induced liver injury both in vivo and in vitro.

METHODS

In vivo: Lipopolysaccharide was intraperitoneally injected into nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (Nrf2^-/-) and wild-type mice to construct a septic liver injury mouse model. Experimental mice were intraperitoneally injected with ferroptosis-1 and intragastrically administered WQY. In vitro: LO2 hepatocytes were stimulated with erastin to activate ferroptosis and later treated with varying concentrations of WQY and an Nrf2 inhibitor (ML385). Pathological damage was evaluated following hematoxylin and eosin staining. Lipid peroxidation levels were assessed using malondialdehyde, superoxide dismutase, and glutathione, as well as reactive oxygen species fluorescent probes. JC-1 staining was performed to evaluate the mitochondrial membrane potential damage. Quantitative reverse transcription polymerase chain reaction and western blot assay were performed to detect the related gene and protein levels. The levels of inflammatory factors were measured using Enzyme-Linked Immunosorbent Assay kits.

RESULTS

In vivo, sepsis-induced liver injury activated ferroptosis in mouse liver tissue. Fer-1 and WQY attenuated septic liver injury, which was associated with increased Nrf2 expression. Deletion of the Nrf2 gene led to aggravation of septic liver injury. The effect of WQY on the attenuation of septic liver injury was partially abolished by the knockdown of Nrf2. In vitro, erastin-induced ferroptosis resulted in decreased hepatocyte viability, lipid peroxidation, and mitochondrial membrane potential damage. WQY protected hepatocytes from erastin-induced ferroptosis by activating Nrf2. The attenuation effect of ferroptosis in hepatocytes by WQY was partially abolished by the inhibition of Nrf2.

CONCLUSION

Ferroptosis has a critical role in the development of sepsis-mediated liver injury. Inhibition of ferroptosis is a possible novel treatment strategy for alleviating septic liver injury. WQY attenuates sepsis-mediated liver injury by suppressing ferroptosis in hepatocytes, which is related to its ability to activate Nrf2.

Cardiac-specific overexpression of catalase attenuates lipopolysaccharide-induced cardiac anomalies through reconciliation of autophagy and ferroptosis

Lipopolysaccharide (LPS) from Gram-negative bacteria is a major contributor to cardiovascular failure, but the signaling mechanisms underlying its stress response are not fully understood. This study aimed to investigate the effect of the antioxidant enzyme catalase on LPS-induced cardiac abnormalities and the mechanisms involved, with particular focus on the interplay between autophagy, ferroptosis, and apoptosis. Cardiac-specific catalase (CAT) overexpression and wild-type (WT) mice were stimulated with LPS (6 mg/kg, intravenous injection), and cardiac morphology and function were evaluated. Oxidative stress, ferroptosis, apoptosis, and mitochondrial status were monitored, and survival curves were plotted based on the results of LPS stimulation. The results showed that, compared with WT mice, mice overexpressing catalase had a higher survival rate under LPS stimulation. Ultrasound echocardiography, cardiomyocyte characteristics, and Masson's trichrome staining showed that LPS inhibited cardiac function and caused cardiac fibrosis, while catalase alleviated these adverse effects. LPS increased apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), increased O₂^·- production, induced inflammation (TNF-α), autophagy, iron toxicity, and carbonyl damage, and significantly damaged mitochondria (mitochondrial membrane potential, mitochondrial proteins, and ultrastructure). These effects were significantly alleviated by catalase. Interestingly, the antioxidant N-acetylcysteine, autophagy inhibitor 3-methyladenine, and ferroptosis inhibitor lipostatin-1 all eliminated the LPS-induced contraction dysfunction and ferroptosis (using lipid peroxidation). Induction of ferroptosis could eliminate the cardioprotective effect of NAC. In conclusion, catalase rescues LPS-induced cardiac dysfunction by regulating oxidative stress, autophagy, ferroptosis, apoptosis, and mitochondrial damage in cardiomyocytes.

LPS-aggravated Ferroptosis via Disrupting Circadian Rhythm by Bmal1/AKT/p53 in Sepsis-Induced Myocardial Injury

Circadian disruption is involved in the progress of sepsis-induced cardiomyopathy (SICM), one of the leading causes of death in sepsis. The molecular mechanism remains ambiguous. In this study, LPS was used to build SICM model in H9c2 cell. The results suggested that LPS induced cytotoxicity via increasing ferroptosis over the time of course. After screening the expressions of six circadian genes, the circadian swing of Bmal1 was dramatically restrained by LPS in H9c2 cell of SIMC vitro model. PcDNA and siRNA were used to upregulate and downregulate Bmal1 and confirmed that Bmal1 inhibited LPS-triggered ferroptosis in H9c2 cells. Then, the results suggested that AKT/p53 pathway was restrained by LPS in H9c2 cell. Rescue test indicated that Bmal1 inhibited LPS-triggered ferroptosis via AKT/p53 pathway in H9c2 cells. In summary, our findings demonstrated that LPS induced cytotoxicity via increasing ferroptosis over the time of course in H9c2 cells and Bmal1 inhibited this toxicity of LPS via AKT/p53 pathway. Although further studies are needed, our findings may contribute to a new insight to mechanism of SICM.

Exploring Dysregulated Ferroptosis-Related Genes in Septic Myocardial Injury Based on Human Heart Transcriptomes: Evidence and New Insights

Introduction

Sepsis is currently a common condition in emergency and intensive care units, and is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Cardiac dysfunction caused by septic myocardial injury (SMI) is associated with adverse prognosis and has significant economic and human costs. The pathophysiological mechanisms underlying SMI have long been a subject of interest. Recent studies have identified ferroptosis, a form of programmed cell death associated with iron accumulation and lipid peroxidation, as a pathological factor in the development of SMI. However, the current understanding of how ferroptosis functions and regulates in SMI remains limited, particularly in the absence of direct evidence from human heart.

Methods

We performed a sequential comprehensive bioinformatics analysis of human sepsis cardiac transcriptome data obtained through the GEO database. The lipopolysaccharide-induced mouse SMI model was used to validate the ferroptosis features and transcriptional expression of key genes.

Results

We identified widespread dysregulation of ferroptosis-related genes (FRGs) in SMI based on the human septic heart transcriptomes, deeply explored the underlying biological mechanisms and crosstalks, followed by the identification of key functional modules and hub genes through the construction of protein-protein interaction network. Eight key FRGs that regulate ferroptosis in SMI, including HIF1A, MAPK3, NOX4, PPARA, PTEN, RELA, STAT3 and TP53, were identified, as well as the ferroptosis features. All the key FRGs showed excellent diagnostic capability for SMI, part of them was associated with the prognosis of sepsis patients and the immune infiltration in the septic hearts, and potential ferroptosis-modulating drugs for SMI were predicted based on key FRGs.

Conclusion

This study provides human septic heart transcriptome-based evidence and brings new insights into the role of ferroptosis in SMI, which is significant for expanding the understanding of the pathobiological mechanisms of SMI and exploring promising diagnostic and therapeutic targets for SMI.

Opportunities and challenges related to ferroptosis in glioma and neuroblastoma

A newly identified form of cell death known as ferroptosis is characterized by the peroxidation of lipids in response to iron. Rapid progress in research on ferroptosis in glioma and neuroblastoma has promoted the exploitation of ferroptosis in related therapy. This manuscript provides a review of the findings on ferroptosis-related therapy in glioblastoma and neuroblastoma and outlines the mechanisms involved in ferroptosis in glioma and neuroblastoma. We summarize some recent data on traditional drugs, natural compounds and nanomedicines used as ferroptosis inducers in glioma and neuroblastoma, as well as some bioinformatic analyses of genes involved in ferroptosis. Moreover, we summarize some data on the associations of ferroptosis with the tumor immunotherapy and TMZ drug resistance. Finally, we discuss future directions for ferroptosis research in glioma and neuroblastoma and currently unresolved issues.

Identification of Molecular Subtypes and a Novel Prognostic Model of Sepsis Based on Ferroptosis-Associated Gene Signature

Ferroptosis has recently been associated with immunological changes in sepsis. However, the clinical significance of ferroptosis-associated genes (FAGs) remains unknown. In this paper, a FAG-based prognostic model was constructed for sepsis patients using an integrated machine learning approach. The prognosis model was composed of 14 FAGs that classify the patients as high or low risk. Based on immunological study, it was found that the immune status differed between the high-risk and low-risk clusters. Cox regression analysis revealed that FAGs were independent risk factors for the overall survival of sepsis patients. ROC curves and nomograms revealed that the FAG-based model was robust for prognosis prediction. Lastly, NEDD4L was identified from the 14 FAGs as a potential hub gene for sepsis prediction.