Ferrostatin-1 inhibits ferroptosis of vascular smooth muscle cells and alleviates abdominal aortic aneurysm formation through activating the SLC7A11/GPX4 axis.

Ferroptosis, a type of iron-catalyzed necrosis, is responsible for vascular smooth muscle cell (VSMC) death and serves as a potential therapeutic target for alleviating aortic aneurysm. Here, our study explored the underlying mechanism of ferroptosis affecting VSMC functions and the resultant formation of AAA using its inhibitor Ferrostatin-1 (Fer-1). Microarray-based gene expression profiling was employed to identify differentially expressed genes related to AAA and ferroptosis. An AAA model was established by angiotensin II (Ang II) induction in apolipoprotein E-knockout (ApoE-/- ) mice, followed by injection of Fer-1 and RSL-3 (ferroptosis inducer). Then, the role of Fer-1 and RSL-3 in the ferroptosis of VSMCs and AAA formation was analyzed in Ang II-induced mice. Primary mouse VSMCs were cultured in vitro and treated with Ang II, Fer-1, sh-SLC7A11, or sh-GPX4 to assess the effect of Fer-1 via the SLC7A11/GPX axis. Bioinformatics analysis revealed that GPX4 was involved in the fibrosis formation of AAA, and there was an interaction between SLC7A11 and GPX4. In vitro assays showed that Fer-1 alleviated Ang II-induced ferroptosis of VSMCs and retard the consequent AAA formation. The mechanism was associated with activation of the SLC7A11/GPX4 pathway. Silencing of SLC7A11 or GPX4 could inhibit the ameliorating effect of Fer-1 on the ferroptosis of VSMCs. In vivo animal studies further demonstrated that Fer-1 inhibited Ang II-induced ferroptosis and vessel wall structural abnormalities in AAA mouse through activation of the SLC7A11/GPX4 pathway. Fer-1 may prevent AAA formation through activation of the SLC7A11/GPX4 pathway.

SRS 16-86 promotes diabetic nephropathy recovery by regulating ferroptosis.

Diabetic nephropathy (DN) is a common complication of diabetes mellitus (DM), and cell death plays an important role. Ferroptosis is a recently discovered type of iron-dependent cell death and one that is different from other kinds of cell death including apoptosis and necrosis. However, ferroptosis has not been described in the context of DN. This study explored the role of ferroptosis in DN pathophysiology and aimed to confirm the efficacy of the ferroptosis inhibitor SRS 16-86 on DN. Streptozotocin injection was used to establish the DM and DN animal models. To investigate the presence or occurrence of ferroptosis in DN, we assessed the concentrations of iron, reactive oxygen species and specific markers associated with ferroptosis in a rat model of DN. Additionally, we performed haematoxylin-eosin staining, blood biochemistry, urine biochemistry and kidney function analysis to evaluate the efficacy of the ferroptosis inhibitor SRS 16-86 in ameliorating DN. We found that SRS 16-86 could improve the recovery of renal function after DN by upregulating glutathione peroxidase 4, glutathione and system xc -light chain and by downregulating the lipid peroxidation markers and 4-hydroxynonenal. SRS 16-86 treatment could improve renal organization after DN. The inflammatory cytokines interleukin 1ß and tumour necrosis factor α and intercellular adhesion molecule 1 were significantly decreased following SRS 16-86 treatment after DN. The results indicate that there is a strong connection between ferroptosis and the pathological mechanism of DN. The efficacy of the ferroptosis inhibitor SRS 16-86 in DN repair supports its use as a new therapeutic treatment for DN.

Design and synthesis of sulfonamide phenothiazine derivatives as novel ferroptosis inhibitors and their therapeutic effects in spinal cord injury.

Ferroptosis is a novel style of cell death, and studies have shown that ferroptosis is strongly associated with spinal cord injury (SCI). A large number of ferroptosis inhibitors have been reported, but so far no ferroptosis inhibitor has been used clinically. Therefore there is an urgent need to discover a better inhibitor of ferroptosis. In this study, 24 novel sulfonamide phenothiazine ferroptosis inhibitors were designed and synthesized, followed by structure-activity relationship studies on these compounds. Among them, compound 23b exhibited the best activity in Erastin-induced PC12 cells (EC50 = 0.001 µM) and demonstrated a low hERG inhibition activity (IC50 > 30 µM). Additionally, compound 23b was identified as a ROS scavenger and showed promising therapeutic effects in an SD rat model of SCI. Importantly, 23b did not display significant toxicity in both in vivo and in vitro experiments and show good pharmacokinetic properties. These findings suggest that compound 23b, a novel ferroptosis inhibitor, holds potential as a therapeutic agent for spinal cord injury and warrants further investigation.

Identifying eleven new ferroptosis inhibitors as neuroprotective agents from FDA-approved drugs.

With increasing evidence that ferroptosis is associated with diverse neurological disorders, targeting ferroptosis offers a promising avenue for developing effective pharmaceutical agents for neuroprotection. In this study, we identified ferroptosis inhibitors as neuroprotective agents from US Food and Drug Administration (FDA)-approved drugs. 1176 drugs have been screened against erastin-induced ferroptosis in HT22 cells, resulting in 89 ferroptosis inhibitors. Among them, 26 drugs showed significant activity with EC50 below10 µM. The most active ferroptosis inhibitor is lumateperone tosylate at nanomolar level. 11 drugs as ferroptosis inhibitors were not reported previously. Further mechanistic studies revealed that their mechanisms of actions involve free radical scavenging, Fe2+ chelation, and 15-lipoxygenase inhibition. Notably, the active properties of some drugs were firstly revealed here. These ferroptosis inhibitors increase the chemical diversity of ferroptosis inhibitors, and offer new therapeutic possibilities for the treatments of related neurological diseases.

Discovery and optimization of olanzapine derivatives as new ferroptosis inhibitors.

Ferroptosis is a new type of cell death associated with many human diseases. It is a new strategy to discover ferroptosis inhibitors for the treatment of ferroptosis-related diseases. Here the FDA-approved drug library containing 1160 molecules was screened for ferroptosis inhibitors in RSL3-induced HT22 mouse hippocampal neuronal cells. As a result, olanzapine showed potent ferroptosis inhibitory activity (EC50 = 1.18 µM). Structural optimization and the structure-activity relationships (SARs) analysis led to the synthesis of 41 new derivatives (4-44) and one known compound 45. Comparing with olanzapine, its derivative 36 showed nearly sixteen-folds improved ferroptosis inhibition and low cytotoxicity (EC50 = 0.074 µM, CC50 = 18.8 µM). Further mechanistic studies revealed that compound 36 specifically inhibited ferroptosis by its antioxidative ability. This work demonstrates that olanzapine protected RSL3-induced ferroptosis in HT22 cell, and its derivative 36 having nanomolar ferroptosis inhibitory activity merit to be developed for drugs against ferroptosis-related neurological diseases.

Discovery of 2-vinyl-10H-phenothiazine derivatives as a class of ferroptosis inhibitors with minimal human Ether-a-go-go related gene (hERG) activity for the treatment of DOX-induced cardiomyopathy.

Ferroptosis was an iron-dependent, nonapoptotic form of regulated cell death. In our previous study, we discovered a potent ferroptosis inhibitor with phenothiazine scaffold (1), but subsequent investigation showed that this compound had potent hERG binding affinity. Herein, we report the discovery of a series of 2-vinyl-10H-phenothiazine derivatives as new class of ferroptosis inhibitors. Structure-activity relationship (SAR) analyses led to the identification of compound 7j, which exhibited significantly reduced hERG inhibition (IC50 > 30 µM) while maintaining high ferroptosis inhibitory activity (EC50 = 0.001 µM on the erastin-induced HT1080 cell ferroptosis model). Further studies confirmed 7j acted as a ROS scavenger and could relieve DOX-induced cardiomyopathy. 7j also displayed favorable pharmacokinetic properties and exhibited no obvious toxicity in vivo and vitro. Overall, this study provides a promising lead compound for drug discovery targeting ferroptosis.

Ferroptosis: A new strategy for targeting Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a complex pathogenesis, which involves the formation of amyloid plaques and neurofibrillary tangles. Many recent studies have revealed a close association between ferroptosis and the pathogenesis of AD. Factors such as ferroptosis-associated iron overload, lipid peroxidation, disturbances in redox homeostasis, and accumulation of reactive oxygen species have been found to contribute to the pathological progression of AD. In this review, we explore the mechanisms underlying ferroptosis, describe the link between ferroptosis and AD, and examine the reported efficacy of ferroptosis inhibitors in treating AD. Finally, we discuss the potential challenges to ferroptosis inhibitors use in the clinic, enabling their faster use in clinical treatment.

Emerging ferroptosis inhibitors as a novel therapeutic strategy for the treatment of neonatal hypoxic-ischemic encephalopathy.

Neonatal hypoxia-ischemia encephalopathy (NHIE), an oxygen deprivation-mediated brain injury due to birth asphyxia or reduced cerebral blood perfusion, often leads to lifelong sequelae, including seizures, cerebral palsy, and mental retardation. NHIE poses a significant health challenge, as one of the leading causes of neonatal morbidity and mortality globally. Despite this, available therapies are limited. Numerous studies have recently demonstrated that ferroptosis, an iron-dependent non-apoptotic regulated form of cell death characterized by lipid peroxidation (LPO) and iron dyshomeostasis, plays a role in the genesis of NHIE. Moreover, recently discovered compounds have been shown to exert potential therapeutic effects on NHIE by inhibiting ferroptosis. This comprehensive review summarizes the fundamental mechanisms of ferroptosis contributing to NHIE. We focus on various emerging therapeutic compounds exhibiting characteristics of ferroptosis inhibition and delineate their pharmacological benefits for the treatment of NHIE. This review suggests that pharmacological inhibition of ferroptosis may be a potential therapeutic strategy for NHIE.

ROS-responsive nanoparticle delivery of ferroptosis inhibitor prodrug to facilitate mesenchymal stem cell-mediated spinal cord injury repair.

Spinal cord injury (SCI) is a traumatic condition that results in impaired motor and sensory function. Ferroptosis is one of the main causes of neural cell death and loss of neurological function in the spinal cord, and ferroptosis inhibitors are effective in reducing inflammation and repairing SCI. Although human umbilical cord mesenchymal stem cells (Huc-MSCs) can ameliorate inflammatory microenvironments and promote neural regeneration in SCI, their efficacy is greatly limited by the local microenvironment after SCI. Therefore, in this study, we constructed a drug-release nanoparticle system with synergistic Huc-MSCs and ferroptosis inhibitor, in which we anchored Huc-MSCs by a Tz-A6 peptide based on the CD44-targeting sequence, and combined with the reactive oxygen species (ROS)-responsive drug nanocarrier mPEG-b-Lys-BECI-TCO at the other end for SCI repair. Meanwhile, we also modified the classic ferroptosis inhibitor Ferrostatin-1 (Fer-1) and synthesized a new prodrug Feborastatin-1 (Feb-1). The results showed that this treatment regimen significantly inhibited the ferroptosis and inflammatory response after SCI, and promoted the recovery of neurological function in rats with SCI. This study developed a combination therapy for the treatment of SCI and also provides a new strategy for the construction of a drug-coordinated cell therapy system.

Ferroptosis inhibitor alleviates sorafenib-induced cardiotoxicity by attenuating KLF11-mediated FSP1-dependent ferroptosis.

Sorafenib is a standard first-line drug for advanced hepatocellular carcinoma, but the serious cardiotoxic effects restrict its therapeutic applicability. Here, we show that iron-dependent ferroptosis plays a vital role in sorafenib-induced cardiotoxicity. Remarkably, our in vivo and in vitro experiments demonstrated that ferroptosis inhibitor application neutralized sorafenib-induced heart injury. By analyzing transcriptome profiles of adult human sorafenib-treated cardiomyocytes, we found that Krüppel-like transcription factor 11 (KLF11) expression significantly increased after sorafenib stimulation. Mechanistically, KLF11 promoted ferroptosis by suppressing transcription of ferroptosis suppressor protein 1 (FSP1), a seminal breakthrough due to its ferroptosis-repressing properties. Moreover, FSP1 knockdown showed equivalent results to glutathione peroxidase 4 (GPX4) knockdown, and FSP1 overexpression counteracted GPX4 inhibition-induced ferroptosis to a substantial extent. Cardiac-specific overexpression of FSP1 and silencing KLF11 by an adeno-associated virus serotype 9 markedly improved cardiac dysfunction in sorafenib-treated mice. In summary, FSP1-mediated ferroptosis is a crucial mechanism for sorafenib-provoked cardiotoxicity, and targeting ferroptosis may be a promising therapeutic strategy for alleviating sorafenib-induced cardiac damage.

Polydopamine Nanoparticles-Encapsulated Ferroptosis Inhibitor Ferstatin-1 Promotes GPX4 Expression by Down-Regulating NOX4 to Alleviate Myocardial Ischemia-Reperfusion Injury.

OBJECTIVE: Polydopamine nanoparticles (PDA NPs) are a promising topic in the fields of drug delivery, tissue engineering, bioimaging, etc. The present study aims to explore the impact of PDA NPs carrying ferroptosis inhibitor ferstatin-1 (Fer-1) on myocardial ischemia-reperfusion injury (MIRI). METHODS: After establishment of a rat model of MIRI and PDA NPs, the rats were divided into 4 groups: model group, sham operation group, Fer-1 group, and nano+Fer-1 group (n=8). To detect the effect of PDA NPs encapsulating Fer-1 on ferroptosis in MIRI rats, we further set up NOX4 overexpression group (pc-NOX4 group), NOX4 inhibitor group (Fulvene-5 group), nano+Fer-1+pc-NOX4 group, and nano+Fer-1+Fulvene-5 group (n=8). A CCK-8 assay was conducted to assess cell viability and staining to detect cardiomyocyte apoptosis and observe myocardial infraction. RESULTS: PDA NPs loaded with Fer-1 were successfully prepared with good safety and biocompatibility. Administration of PDA NPs carrying Fer-1 notably alleviated myocardial injury and hindered the process of ferroptosis in MIRI rats when inducing downregulation of NOX4 expression. Additionally, overexpression of GPX4 significantly attenuated myocardial injury in MIRI rats. While Fer-1 was shown to inhibit the expression of NOX4, the NOX4 inhibitor Fulvene-5 greatly elevated GPX4 and FTH1 expression in cardiomyocytes, and down-regulated the content of Fe2+, especially in the nanometer+Fer-1+Fulvene-5 group. CONCLUSION: With promising safety and biocompatibility, PDA NPs encapsulated Fer-1 decrease GPX4 and FTH1 expression by inhibiting the level of NOX4 in myocardial cells of MIRI rats, thereby suppressing ferroptosis of cardiomyocytes and alleviating myocardial injury.

Defining the ferroptotic phenotype of beta cells in type 1 diabetes and its inhibition as a potential antidiabetic strategy.

Introduction: Recently, the involvement of ferroptotic cell death in the reduction of ß-cell mass in diabetes has been demonstrated. To elucidate the mechanisms of ß-cell ferroptosis and potential antidiabetic effects of the ferroptosis inhibitor ferrostatin-1 (Fer-1) in vivo, a mouse model of type 1 diabetes (T1D) was used. Methods: Animals were divided into three groups: control (vehicle-treated), diabetic (streptozotocin-treated, 40 mg/kg, from days 1-5), and diabetic treated with Fer-1 (1 mg/kg, from days 1-21). On day 22, glycemia and insulinemia were measured and pancreases were isolated for microscopic analyses. Results: Diabetes disturbed general parameters of ß-cell mass (islet size, ß-cell abundance and distribution) and health (insulin and PDX-1 expression), increased lipid peroxidation in islet cells, and phagocytic removal of iron-containing material. It also downregulated the main players of the antiferroptotic pathway - Nrf2, GPX4, and xCT. In contrast, Fer-1 ameliorated the signs of deterioration of ß-cell/islets, decreased lipid peroxidation, and reduced phagocytic activity, while upregulated expression of Nrf2 (and its nuclear translocation), GPX4, and xCT in ß-cell/islets. Discussion: Overall, our study confirms ferroptosis as an important mode of ß-cell death in T1D and suggests antiferroptotic agents as a promising strategy for the prevention and treatment of diabetes.

Targeting ferroptosis as a promising therapeutic strategy to treat cardiomyopathy.

Cardiomyopathies are a clinically heterogeneous group of cardiac diseases characterized by heart muscle damage, resulting in myocardium disorders, diminished cardiac function, heart failure, and even sudden cardiac death. The molecular mechanisms underlying the damage to cardiomyocytes remain unclear. Emerging studies have demonstrated that ferroptosis, an iron-dependent non-apoptotic regulated form of cell death characterized by iron dyshomeostasis and lipid peroxidation, contributes to the development of ischemic cardiomyopathy, diabetic cardiomyopathy, doxorubicin-induced cardiomyopathy, and septic cardiomyopathy. Numerous compounds have exerted potential therapeutic effects on cardiomyopathies by inhibiting ferroptosis. In this review, we summarize the core mechanism by which ferroptosis leads to the development of these cardiomyopathies. We emphasize the emerging types of therapeutic compounds that can inhibit ferroptosis and delineate their beneficial effects in treating cardiomyopathies. This review suggests that inhibiting ferroptosis pharmacologically may be a potential therapeutic strategy for cardiomyopathy treatment.

Ferroptosis Inhibitors as New Therapeutic Insights into Radiation-Induced Heart Disease.

Radiation-induced heart disease (RIHD) is a significant cause of morbidity in breast and other mediastinal cancers. The many molecular and cellular patho-mechanisms that have a role in RIHD are not completely understood. Endothelial injury, oxidative stress, and inflammation, as well as endoplasmic reticulum and mitochondrial damage, are considered the primary causes of RIHD. Ferroptosis is a newly discovered type of cell death that results from irondependent lipid peroxide accumulation. As ferroptosis plays an important role in the pathogenesis of cardiovascular diseases, it seems that it has a significant effect on RIHD. It was recently shown that ionizing radiation (IR) generates severe ferroptosis, which is a critical component of Radiotherapy-mediated normal cell toxicity. These findings support the use of a ferroptosis inhibitor to reduce RIHD. In this perspective review, we summarize the role of ferroptosis in pathogens of cardiovascular disease and radiation toxicity, and we will introduce ferroptosis inhibitors as a new strategy to prevent or reduce RIHD.

Pharmacological inhibition of ferroptosis as a therapeutic target for sepsis-associated organ damage.

Sepsis is a complex clinical syndrome caused by dysfunctional host response to infection, which contributes to excess mortality and morbidity worldwide. The development of life-threatening sepsis-associated organ injury to the brain, heart, kidneys, lungs, and liver is a major concern for sepsis patients. However, the molecular mechanisms underlying sepsis-associated organ injury remain incompletely understood. Ferroptosis, an iron-dependent non-apoptotic form of cell death characterized by lipid peroxidation, is involved in sepsis and sepsis-related organ damage, including sepsis-associated encephalopathy, septic cardiomyopathy, sepsis-associated acute kidney injury, sepsis-associated acute lung injury, and sepsis-induced acute liver injury. Moreover, compounds that inhibit ferroptosis exert potential therapeutic effects in the context of sepsis-related organ damage. This review summarizes the mechanism by which ferroptosis contributes to sepsis and sepsis-related organ damage. We focus on the emerging types of therapeutic compounds that can inhibit ferroptosis and delineate their beneficial pharmacological effects for the treatment of sepsis-related organ damage. The present review highlights pharmacologically inhibiting ferroptosis as an attractive therapeutic strategy for sepsis-related organ damage.

Engineering Ferroptosis Inhibitors as Inhalable Nanomedicines for the Highly Efficient Treatment of Idiopathic Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) refers to chronic progressive fibrotic interstitial pneumonia. It is called a "tumor-like disease" and cannot be cured using existing clinical drugs. Therefore, new treatment options are urgently needed. Studies have proven that ferroptosis is closely related to the development of IPF, and ferroptosis inhibitors can slow down the occurrence of IPF by chelating iron or reducing lipid peroxidation. For example, the ferroptosis inhibitor deferoxamine (DFO) was used to treat a mouse model of pulmonary fibrosis, and DFO successfully reversed the IPF phenotype and increased the survival rate of mice from 50% to 90%. Given this, we perceive that the treatment of IPF by delivering ferroptosis inhibitors is a promising option. However, the delivery of ferroptosis inhibitors faces two bottlenecks: low solubility and targeting. For one thing, we consider preparing ferroptosis inhibitors into nanomedicines to improve solubility. For another thing, we propose to deliver nanomedicines through pulmonary drug-delivery system (PDDS) to improve targeting. Compared with oral or injection administration, PDDS can achieve better delivery and accumulation in the lung, while reducing the systemic exposure of the drug, and is an efficient and safe drug-delivery method. In this paper, three possible nanomedicines for PDDS and the preparation methods thereof are proposed to deliver ferroptosis inhibitors for the treatment of IPF. Proper administration devices and challenges in future applications are also discussed. In general, this perspective proposes a promising strategy for the treatment of IPF based on inhalable nanomedicines carrying ferroptosis inhibitors, which can inspire new ideas in the field of drug development and therapy of IPF.

Discovery of novel diphenylbutene derivative ferroptosis inhibitors as neuroprotective agents.

Ferroptosis is a regulated and iron-dependent cell death. Ferroptosis inhibitors are promising for treating many neurological diseases. Herein, with phenotypic assays, we discovered a new diphenylbutene derivative ferroptosis inhibitor, DPT. Based on this hit, we synthesized fourteen new diphenylbutene derivatives, evaluated their ferroptosis inhibitory activities in HT22 mouse hippocampal neuronal cells, and found that three compounds exhibited improved inhibitory activities compared with DPT. Among these active compounds, compound 3f displayed the most potent anti-ferroptosis activity (EC50 = 1.7 µM). Further studies demonstrated that 3f is a specific ferroptosis inhibitor. And we revealed that different from the classic ferroptosis inhibitors, 3f blocked ferroptosis by increasing FSP1 protein level. Moreover, 3f can penetrate blood-brain barrier (BBB). In a rat model of ischemic stroke, 3f effectively mitigated cerebral ischemic injury. Therefore, we are confirmed that 3f, as a novel ferroptosis inhibitor with a new scaffold, is promising for further development as an agent against neurological diseases.

Molecular mechanism of ferroptosis and its role in the occurrence and treatment of diabetes.

Ferroptosis is an iron-dependent programmed cell death, which is different from apoptosis, necrosis, and autophagy. Specifically, under the action of divalent iron or ester oxygenase, unsaturated fatty acids that are highly expressed on the cell membrane are catalyzed to produce lipid peroxidation, which induces cell death. In addition, the expression of the antioxidant system [glutathione (GSH) and glutathione peroxidase 4 (GPX4)] is decreased. Ferroptosis plays an important role in the development of diabetes mellitus and its complications. In this article, we review the molecular mechanism of ferroptosis in the development of diabetes mellitus and its complications. We also summarize the emerging questions in this particular area of research, some of which remain unanswered. Overall, this is a comprehensive review focusing on ferroptosis-mediated diabetes and providing novel insights in the treatment of diabetes from the perspective of ferroptosis.

Ferrostatin-1 Ameliorates Liver Dysfunction via Reducing Iron in Thioacetamide-induced Acute Liver Injury in Mice.

Background and Aims: Hepatic iron overload always leads to oxidative stress, which has been found to be involved in the progression of liver disease. However, whether iron disorder is involved in acute liver disease and the further molecular mechanisms remain unclear. Methods: A mice model of acute liver injury (ALI) was established via intraperitoneal injection of thioacetamide (TAA) (250 mg/kg/day) for 3 consecutive days. Ferrostatin-1 (Fer-1) was administered intraperitoneally (2.5 µM/kg/day) starting 3 days before TAA treatment. Deferoxamine (DFO) was intraperitoneally injected (200 mg/kg/day) with TAA treatment for 3 days. We further observed the effect of Fer-1 on TAA model with high-iron diet feeding. ALI was confirmed using histological examination and liver function activity. Moreover, expressions of iron metabolism and ferroptosis proteins were measured by Western blot analysis. Results: The study revealed that the iron accumulation and ferroptosis contributed to TAA-induced ALI pathogenesis. TAA induced prominent inflammation and vacuolar degeneration in the liver as well as liver dysfunction. In addition, protein expression of the cystine/glutamate antiporter SLC7A11 (xCT) and glutathione peroxidase 4 (GPX4) was significantly decreased in the liver, while transferrin receptor 1 (TfR1), ferroportin (Fpn) and light chain of ferritin (Ft-L) expression levels were increased after TAA exposure. As the same efficiency as DFO, pre-administration of Fer-1 significantly decreased TAA-induced alterations in the plasma ALT, AST and LDH levels compared with the TAA group. Moreover, both Fer-1 and DFO suppressed TfR1, Fpn and Ft-L protein expression and decreased iron accumulation, but did not affect xCT or GPX4 expression in the liver. Both Fer-1and DFO prevented hepatic ferroptosis by reducing the iron content in the liver. Furthermore, Fer-1 also reduced iron and reversed liver dysfunction under iron overload conditions. Conclusion: These findings indicate a role of TAA-induced iron accumulation and ferroptosis in the pathogenesis of ALI model. The effect of Fer-1 was consistent with that of DFO, which prevented hepatic ferroptosis by reducing the iron content in the liver. Thus, Fer-1 might be a useful reagent to reverse liver dysfunction and decreasing the iron content of the liver may be a potential therapeutic strategy for ALI.

Discovery of phloroglucinols from Hypericum japonicum as ferroptosis inhibitors.

Ferroptosis is a new type of cell death, which involves central neuronal system. Inhibition of ferroptosis is a promising strategy to prevent and treat neurological diseases. Thirteen phloroglucinols (1-13) were obtained from the whole plants of Hypericum japonicum. Of them, compounds 1-3 are new ones. Their structures were elucidated by extensive analysis of spectroscopic data and X-ray diffraction. All the isolates were evaluated for their inhibitory effect on RSL3-induced ferroptosis. Two new compounds 2-3 showed significant inhibitory effect with EC50 of 0.48 ± 0.14 µM and 0.94 ± 0.14 µM, respectively. DPPH free radical scavenging abilities of all compounds were assessed to evaluate their antioxidant effect. This work first reports the anti-ferroptosis activity of phloroglucinols.