Antifungal Activity of the Lipophilic Antioxidant Ferrostatin-1

Broadening horizons: ferroptosis as a new target for traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide, with ~50 million people experiencing TBI each year. Ferroptosis, a form of regulated cell death triggered by iron ion-catalyzed and reactive oxygen species-induced lipid peroxidation, has been identified as a potential contributor to traumatic central nervous system conditions, suggesting its involvement in the pathogenesis of TBI. Alterations in iron metabolism play a crucial role in secondary injury following TBI. This study aimed to explore the role of ferroptosis in TBI, focusing on iron metabolism disorders, lipid metabolism disorders and the regulatory axis of system Xc-/glutathione/glutathione peroxidase 4 in TBI. Additionally, we examined the involvement of ferroptosis in the chronic TBI stage. Based on these findings, we discuss potential therapeutic interventions targeting ferroptosis after TBI. In conclusion, this review provides novel insights into the pathology of TBI and proposes potential therapeutic targets.

Polyphyllin I induced ferroptosis to suppress the progression of hepatocellular carcinoma through activation of the mitochondrial dysfunction via Nrf2/HO-1/GPX4 axis

BACKGROUND

Ferroptosis is an emerging iron-dependent programmed cell death mode characterized by lipid peroxidation and iron accumulation, closely associated with Hepatocellular Carcinoma (HCC) progression. Although the impact of Polyphyllin I (PPI), a prominent bioactive constituent derived from Paris polyphylla, on diverse malignancies has been established, the specific role and potential mechanistic pathways through which PPI modulates ferroptosis in HCC remain elusive.

PURPOSE

This study aimed to elucidate the anti-cancer properties and potential mechanisms of PPI in inducing ferroptosis and triggering mitochondrial injury in HCC.

METHODS

Cell viability was assessed using CCK-8 assays. EdU proliferation and colony formation assays were employed to evaluate cell proliferation. A wound-healing assay was performed to assess cell migration. Transwell assay was utilized to evaluate cell invasion. Ferroptosis was evaluated through the utilization of a FerroOrange fluorescent probe, malondialdehyde (MDA) and reduced glutathione (GSH) assay kits, DCFH-DA fluorescent probe, western blotting, and transmission electron microscopy (TEM) analysis. Molecular docking, immunofluorescence, and western blotting were employed to predict and validate the binding and interaction of PPI with Nrf2, HO-1, xCT, and GPX4. Mitochondrial structure and membrane potential changes were evaluated using JC-1 and Mito Tracker Green fluorescent probes. A nude mice xenograft model was constructed to determine the inhibitory effects and the levels of ferroptosis of PPI on HCC through hematoxylin and eosin (H&E), Prussian blue reaction, immunofluorescence staining, immunohistochemistry, and western blotting analysis, in vivo.

RESULTS

PPI exhibited dose-dependent inhibitory effects on the proliferation, invasion, and metastasis of HCC cells mediated by increasing reactive oxygen species (ROS) and MDA levels, promoting Fe2+ accumulation, depleting GSH, and suppressing the expression of xCT and GPX4, thereby inducing ferroptosis in HCC. The induction of ferroptosis by PPI was associated with the binding of PPI to Nrf2, HO-1, and GPX4 proteins, modulating the Nrf2/HO-1/GPX4 antioxidant axis. PPI also induced mitochondrial structural damage and decreased mitochondrial membrane potential (MMP). Inhibition of ferroptosis by ferrostatin-1 (Fer-1) mitigated the mitochondrial disruption induced by PPI. In vivo, PPI inhibited Nrf2/HO-1/GPX4 axis-induced ferroptosis, impeding HCC growth similar to the effects of sorafenib.

CONCLUSION

These results demonstrated that PPI intervention can suppress the proliferation, invasion, and metastasis of HCC cells by enhancing mitochondrial disruption and inducing ferroptosis via the Nrf2/HO-1/GPX4 axis. Consequently, our research advances the frontiers of pharmacodynamics and deepens our comprehension of the intricate mechanisms underpinning PPI. Furthermore, it has yielded an innovative treatment stratagem rooted in the tenets of Traditional Chinese Medicine (TCM), thereby furnishing a novel therapeutic avenue for addressing HCC.

Glycolipotoxicity conferred tendinopathy through ferroptosis dictation of tendon-derived stem cells by YAP activation

Tendinopathy is a condition characterized by chronic, complex, and multidimensional pathological changes in the tendons. The etiology of tendinopathy is the combination of several factors, and diabetes mellitus (DM) is a risk factor. Increasing evidence has shown that the diabetic microenvironment plays an important role in tendinopathy. However, the mechanism causing tendinopathy in patients with DM remains unclear. Our study found that ferroptosis played an important role in tendinopathy in patients with DM. In vitro, high glucose and high fat treatment was used to simulate the DM microenvironment. Results showed that such a mechanism significantly increased ferroptosis, which was characterized by mass cell death, lipid peroxide accumulation, mitochondrial morphological changes, mitochondrial membrane potential decline, iron overload, and the activation of ferroptosis-related genes, in tendon-derived stem cells cultured in vitro. In the animal studies, db/db mice were used in the DM model, and the db mice had severe tendon injury and high ACSL4 and TfR1 expressions. These phenomena could be alleviated by the ferroptosis inhibitor ferrostatin-1. In conclusion, ferroptosis is associated with tendinopathy in patients with DM, and ferroptosis targeting may be a novel approach for treating diabetic tendinopathy. Our results can provide a new strategy for managing tendinopathy clinically in patients with DM.

Mitophagy contributes to zinc-induced ferroptosis in porcine testis cells

Zinc (Zn) is a critical microelement for physiological process, but excess exposure can cause testicular dysfunction. However, the underlying mechanism of Zn-induced ferroptosis via regulating mitophagy is unknown. In this study, a total of 60 male weaned pigs were randomly divided into three groups and the content of Zn were 75 mg/kg (control), 750 mg/kg (Zn-I), 1500 mg/kg (Zn-II). Meanwhile, testicular cells were treated with ZnSO4 (0, 50 and 100 μM), and in combination of ZnSO4 (100 μM) and ferrostation-1, ML-210, or 3-methyladenine for 24 h. Our results verified that Zn could cause ferroptosis and lipid peroxidation, which were characterized by down-regulating level of SLC7A11, GPX4, and ferritin, and up-regulating levels of MDA, CD71, TF, and HMGB1 by Western blot, immunohistochemistry, immunofluorescence, peroxidase assay, et.ac. The opposite effect was shown after treatment with ferrostation-1 or ML-210. Meanwhile, the mitophagy-related proteins (PINK, Parkin, ATG5, LC3-II/LC3-I) were significantly upregulated in vivo and in vitro. Most importantly, 3-methyladenine observably relieved ferroptosis under Zn treatment through inhibiting mitophagy. Collectively, we demonstrated that mitophagy contributes to Zn-induced ferroptosis in porcine testis cells, providing a new insight into Zn toxicology.

Nobiletin alleviates myocardial ischemia-reperfusion injury via ferroptosis in rats with type-2 diabetes mellitus

Susceptibility to myocardial ischemia-reperfusion (IR) injury in type-2 diabetes (T2DM) remains disputed, although studies have reported that ferroptosis is associated with myocardial IR injury. Nobiletin, a flavonoid isolated from citrus peels, is an antioxidant that possesses anti-inflammatory and anti-diabetic activities. However, it remains unknown whether nobiletin has any protective effects on susceptibility to myocardial IR injury during T2DM in rats via ferroptosis. To investigate the effects and underlying mechanisms of nobiletin on myocardial IR injury during T2DM, we induced myocardial IR model in rats at T2DM onset vs mature disease. We also established a high-fat high-glucose (HFHG) and hypoxia-reoxygenation (H/R) model in H9c2 cells to imitate abnormal glycolipid metabolism during T2DM. Myocardial injury, oxidative stress and ferroptosis towards myocardial IR in rats with mature T2DM but not at T2DM onset were increased. These changes were restored under treatment with ferrostain-1 or nobiletin. Both ferrostain-1 and nobiletin decreased the expression of ferroptosis-related proteins including Acyl-CoA synthetase long chain family member 4 (ACSL4) and nuclear receptor coactivator 4 (NCOA4) but not glutathione peroxidase 4 (GPX4) in rats with mature T2DM and cells with HFHG and H/R injury. Nobiletin strengthened the effect of si-ACSL4 on inhibiting ACSL4 expression, and also inhibited the effect of Erastin or oe-ACSL4 on increasing ACSL4 expression. Taken together, our data indicates that ferroptosis involves in susceptibility to myocardial IR injury in rats during T2DM. Nobiletin has therapeutic potential for alleviating myocardial IR injury associated with ACSL4- and NCOA4-related ferroptosis.

Ferrostatin-1 Inhibits Toll-Like Receptor 4/NF-κB Signaling to Alleviate Intervertebral Disc Degeneration in Rats

Ferrostatin-1 (Fer-1) is an inhibitor of ferroptosis and has been documented to be implicated in the development of intervertebral disc degeneration (IDD). This study intends to explore the role of Fer-1 in IDD via the toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Through the Gene Expression Omnibus database, IDD-related gene expression microarray GSE124272 and high-throughput sequencing data set GSE175710 were obtained. Then, differentially expressed genes in IDD were identified, followed by implementation of protein-protein interaction network analysis and receiver operating characteristic curve analysis. Main pathways in IDD were obtained through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional analyses, and target genes of Fer-1 were obtained through PubChem and PharmMapper websites. Finally, GPX4, FTH, and TLR4 expression was determined in a constructed IDD rat model. Three key co-expression modules involved in IDD were obtained through Weighted Gene Co-Expression Network Analysis. Thirteen differentially expressed genes were found to be associated with IDD, and eight key genes (TLR4, BCL2A1, CXCL1, IL1R1, NAMPT, SOCS3, XCL1, and IRAK3) were found to affect IDD. These eight key genes had the diagnostic potential for IDD. The NF-κB signaling pathway played a predominant role in IDD development. From network pharmacologic analysis, Fer-1 might suppress ferroptosis and ameliorate IDD via the TLR4/NF-κB signaling pathway, and the in vivo animal experiment further verified it. Fer-1 down-regulates TLR4 to inactivate NF-κB signaling pathway, suppressing ferroptosis and finally alleviating IDD in rats.

IL-23 signaling prevents ferroptosis-driven renal immunopathology during candidiasis

During infection the host relies on pattern-recognition receptors to sense invading fungal pathogens to launch immune defense mechanisms. While fungal recognition and immune effector responses are organ and cell type specific, during disseminated candidiasis myeloid cells exacerbate collateral tissue damage. The β-glucan receptor ephrin type-A 2 receptor (EphA2) is required to initiate mucosal inflammatory responses during oral Candida infection. Here we report that EphA2 promotes renal immunopathology during disseminated candidiasis. EphA2 deficiency leads to reduced renal inflammation and injury. Comprehensive analyses reveal that EphA2 restrains IL-23 secretion from and migration of dendritic cells. IL-23 signaling prevents ferroptotic host cell death during infection to limit inflammation and immunopathology. Further, host cell ferroptosis limits antifungal effector functions via releasing the lipid peroxidation product 4-hydroxynonenal to induce various forms of cell death. Thus, we identify ferroptotic cell death as a critical pathway of Candida-mediated renal immunopathology that opens a new avenue to tackle Candida infection and inflammation.

Long non-coding RNA ADAMTS9-AS1 attenuates ferroptosis by Targeting microRNA-587/solute carrier family 7 member 11 axis in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) accounts for approximately 90% of all ovarian cancer cases and is the most common cause of gynecological cancer death. Understanding the molecular mechanisms of EOC will help develop better diagnostics and more effective treatments. This study aimed to investigate whether long non-coding RNA ADAMTS9-AS1 (ADAMTS9-AS1) could regulate solute carrier family 7 member 11 (SLC7A11) expression and inhibit ferroptosis by sponging micoRNA-587 in EOC progression. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting results showed that ADAMTS9-AS1 expression was elevated in EOC cells; microRNA-587 expression was up-regulated and SLC7A11 expression was down-regulated after knocking down ADAMTS9-AS1 by transfection with siRNAs; however, microRNA-587 inhibitor reversed SLC7A11 expression in ADAMTS9-AS1 knocking down cells. Ferroptosis related marker detection and cell function assay confirmed that knocking down ADAMTS9-AS1 inhibited EOC cells proliferation and migration by promoting ferroptosis. Overexpression of micoRNA-587 also promoted ferroptosis while inhibited cells proliferation and migration in EOC cells. Additionally, micoRNA-587 inhibitor reversed the effect of ADAMTS9-AS1 silence on the ferroptosis and cell function. Moreover, dual-luciferase reporter gene assay and RNA immunoprecipitation assay confirmed that miR-587 was as a sponge for ADAMTS9-AS1 and SLC7A11. In conclusion, our study found that ADAMTS9-AS1 attenuated ferroptosis by targeting miR-587/SLC7A11 axis in EOC. Our study provides a new therapeutic target for EOC.

Ferrostatin-1 Polarizes Microglial Cells Toward M2 Phenotype to Alleviate Inflammation After Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is one of the most lethal stroke types and lacks effective therapeutic regimens. Recently, evidence has suggested the involvement of the ferroptosis inhibitor ferrostatin-1 (Fer-1) in the pathophysiological process of ICH. In this study, we examined the underlying mechanism.

METHODS

We induced an in vitro apoptosis model in organotypic hippocampal slice (OHS) using hemoglobin (Hb) and an in vivo ICH model using collagenase. OHSs were treated with MK-801, Fer-1, glutamate, and Hb to assess the impacts of Fer-1 on neuron apoptosis, glutathione peroxidase-4 activity, reactive oxygen species production, inflammation-related factors, expression of M1 markers and M2 markers, and the phagocytic function of microglial cells in vitro. Then, ICH mice were treated with Fer-1 and ruxolitinib to evaluate the effects of Fer-1-orchestrating janus kinase 1/signal transducer and activator of transcription 6 pathway on neurological function, brain water content, hematoma volume, the anti-inflammatory factor, M1 and M2 markers, and the phagocytic function of microglial cells in vivo.

RESULTS

Hb or glutamate facilitated glutathione peroxidase dysfunction, reactive oxygen species production, and neuronal apoptosis in OHSs, which was nullified by Fer-1. Fer-1 polarized microglial cells to the M2 phenotype, enhanced their phagocytic function, and prevented inflammation in Hb-induced OHSs. In the ICH mouse model, Fer-1 was found to improve neurological function and promote hematoma absorption. In addition, Fer-1 activated the Fer-1-orchestrating janus kinase 1/signal transducer and activator of transcription 6 pathway, which accelerated microglial M2 polarization, enhanced the phagocytic function of microglial cells, and restrained inflammation in ICH mice.

CONCLUSIONS

Overall, our findings suggest that Fer-1 may be a novel mechanism underlying microglial M2 polarization and inflammation after ICH.

Insight into the Double-Edged Role of Ferroptosis in Disease

Ferroptosis, a newly described type of iron-dependent programmed cell death that is distinct from apoptosis, necroptosis, and other types of cell death, is involved in lipid peroxidation (LP), reactive oxygen species (ROS) production, and mitochondrial dysfunction. Accumulating evidence has highlighted vital roles for ferroptosis in multiple diseases, including acute kidney injury, cancer, hepatic fibrosis, Parkinson's disease, and Alzheimer's disease. Therefore, ferroptosis has become one of the research hotspots for disease treatment and attracted extensive attention in recent years. This review mainly summarizes the relationship between ferroptosis and various diseases classified by the system, including the urinary system, digestive system, respiratory system, nervous system. In addition, the role and molecular mechanism of multiple inhibitors and inducers for ferroptosis are further elucidated. A deeper understanding of the relationship between ferroptosis and multiple diseases may provide new strategies for researching diseases and drug development based on ferroptosis.

Is Ferroptosis a Future Direction in Exploring Cryptococcal Meningitis?

Cryptococcal meningitis (CM) is the leading cause of mortality among patients infected with human immunodeficiency virus (HIV). Although treatment strategies for CM are continually being developed, the mortality rate is still high. Therefore, we need to explore more therapeutic strategies that are aimed at hindering its pathogenic mechanism. In the field of CM, several studies have observed rapid iron accumulation and lipid peroxidation within the brain, all of which are hallmarks of ferroptosis, which is a type of programmed cell death that is characterized by iron dependence and lipid peroxidation. In recent years, many studies have confirmed the involvement of ferroptosis in many diseases, including infectious diseases such as Mycobacterium tuberculosis infection and coronavirus disease-2019 (COVID-19). Furthermore, ferroptosis is considered as immunogenic and pro-inflammatory as the ferroptotic cells release damage-associated molecular pattern molecules (DAMPs) and alarmin, both of which regulate immunity and pro-inflammatory activity. Hence, we hypothesize that there might be a relationship between this unique cell death modality and CM. Herein, we review the evidence of ferroptosis in CM and consider the hypothesis that ferroptotic cell death may be involved in the cell death of CM.

Hypoxia protects H9c2 cells against Ferroptosis through SENP1-mediated protein DeSUMOylation

Hypoxia affects proliferation, differentiation, as well as death of cardiomyocyte, and plays an important role in the development of myocardial ischemia. However, the detailed mechanisms through which hypoxia regulates cardiomyocyte ferroptosis have not been explored. In this study, we revealed that hypoxia suppresses the proliferation, migration, and erastin-induced ferroptosis of H9c2 cells. First, we confirmed the upregulation of SENP1 in H9c2 cells cultured under hypoxic conditions. Through adenovirus-mediated SENP1 gene transfection, we demonstrated that SENP1 overexpression could enhance H9c2 cell proliferation and migration while also protecting H9c2 cells from erastin-induced ferroptosis. Furthermore, through immunoprecipitation and western blotting, we confirmed that SENP1 mediated deSUMOylation of HIF-1α and ACSL4 in H9c2 cells. In conclusion, this study describes the underlying mechanism through which hypoxia upregulates SENP1 expression, in turn protecting against ferroptosis via the regulation of HIF-1α and ACSL4 deSUMOylation. Our findings provide a theoretical foundation for the development of novel therapeutics for ischemic heart diseases.

Where ferroptosis inhibitors and paraquat detoxification mechanisms intersect, exploring possible treatment strategies

Paraquat (PQ) is a fast-acting and effective herbicide that is used throughout the world to eliminate weeds. Over the past years, PQ was considered one of the most popular poisoning substances for suicide, and PQ poisoning accounts for about one-third of suicides around the world. Poisoning with PQ may cause multiorgan failure, pulmonary fibrosis, and ultimately death. Exposure to PQ results in the accumulation of PQ in the lungs, causing severe damage and, eventually, fibrosis. Until now, no effective antidote has been found to treat poisoning with PQ. In general, the toxicity of PQ is due to the formation of high energy oxygen free radicals and the peroxidation of unsaturated lipids in the cell. Ferroptosis is the result of the loss of glutathione peroxidase 4 (GPX4) activity that transforms iron-dependent lipid hydroperoxides to lipid alcohols, which are inert in the biological environment. Impaired iron metabolism and lipid peroxidation are increasingly known as the driving agents of ferroptosis. The contribution of ferroptosis to the development of cell death during poisoning with PQ has not yet been addressed. There is growing evidence about the relationship between PQ poisoning and ferroptosis. This raises the possibility of using ferroptosis inhibitors for the treatment of PQ poisoning. In this hypothesis-driven review article, we elaborated how ferroptosis inhibitors might circumvent the toxicity induced by PQ and may be potentially useful for the treatment of PQ toxicity.

Mitochondria regulation in ferroptosis

Ferroptosis is recognized as a new form of regulated cell death which is initiated by severe lipid peroxidation relying on reactive oxygen species (ROS) generation and iron overload. This iron-dependent cell death manifests evident morphological, biochemical and genetic differences from other forms of regulated cell death, such as apoptosis, autophagy, necrosis and pyroptosis. Ferroptosis was primarily characterized by condensed mitochondrial membrane densities and smaller volume than normal mitochondria, as well as the diminished or vanished of mitochondria crista and outer membrane ruptured. Mitochondria take the center role in iron metabolism, as well as substance and energy metabolism as it's the major organelle in iron utilization, catabolic and anabolic pathways. Interference of key regulators of mitochondrial lipid metabolism (e.g., ASCF2 and CS), iron homeostasis (e.g., ferritin, mitoferrin1/2 and NEET proteins), glutamine metabolism and other signaling pathways make a difference to ferroptotic sensitivity. Targeted induction of ferroptosis was also considered as a potential therapeutic strategy to some oxidative stress diseases, including neurodegenerative disorders, ischemia-reperfusion injury, traumatic spinal cord injury. However, the pertinence between mitochondria and ferroptosis is still in dispute. Here we systematic elucidate the morphological characteristics and metabolic regulation of mitochondria in the regulation of ferroptosis.

Regulation of lipid peroxidation and ferroptosis in diverse species

This review by Conrad et al. reviews the functions and regulation of lipid peroxidation, ferroptosis, and the antioxidant network in diverse species, including humans, other mammals and vertebrates, plants, invertebrates, yeast, bacteria, and archaea, and discusses the potential evolutionary roles of lipid peroxidation and ferroptosis.

Lipid peroxidation is the process by which oxygen combines with lipids to generate lipid hydroperoxides via intermediate formation of peroxyl radicals. Vitamin E and coenzyme Q₁₀ react with peroxyl radicals to yield peroxides, and then these oxidized lipid species can be detoxified by glutathione and glutathione peroxidase 4 (GPX4) and other components of the cellular antioxidant defense network. Ferroptosis is a form of regulated nonapoptotic cell death involving overwhelming iron-dependent lipid peroxidation. Here, we review the functions and regulation of lipid peroxidation, ferroptosis, and the antioxidant network in diverse species, including humans, other mammals and vertebrates, plants, invertebrates, yeast, bacteria, and archaea. We also discuss the potential evolutionary roles of lipid peroxidation and ferroptosis.