Ferrostatin-1 alleviates skin inflammation and inhibits ferroptosis of neutrophils and CD8+ T cells in allergic contact dermatitis.

BACKGROUND: Ferroptosis is considered as an immunogenic type of regulated cell death and associated with the pathogenesis of inflammatory skin diseases. However, the involvement and function of ferroptosis in allergic contact dermatitis (ACD) remains unknown. OBJECTIVE: To explore the role of ferroptosis in ACD. To reveal which type of cells develops ferroptosis in ACD. METHODS: We detected the key markers of ferroptosis in 1-Chloro-2,4-dinitrochlorobenzene (DNCB)-induced ACD mice model. We applicated ferrostatin-1 (Fer-1) to restrain ferroptosis in ACD mice and then compared the severity of dermatitis and the level of inflammation and ferroptosis in dermis and epidermis, respectively. Keratinocyte-specific Gpx4 conditional knockout (cKO) mice were used to investigate the function of keratinocyte ferroptosis in the development of ACD. Single-cell RNA sequencing was conducted to analyze the affection of Fer-1 on different type of cells in ACD. RESULTS: Ferroptosis was involved in DNCB-induced ACD mice. Ferroptosis activation was more remarkable in dermis rather than in epidermis. Gpx4 cKO mice showed similar severity of skin dermatitis as control mice. Fer-1 alleviated skin inflammation in mice and reduced ferroptosis in neutrophils and CD8+ T cells both of which contribute to development of ACD. CONCLUSION: Ferroptosis was activated in immune cells, especially neutrophils and CD8+ T cells in DNCB-induced ACD mice. Fer-1 treatment inhibited ferroptosis of neutrophils and CD8+ T cells and relieved skin damage in ACD mice.

Nicotinamide mononucleotide mitigates neuroinflammation by enhancing GPX4-mediated ferroptosis defense in microglia.

BACKGROUND: Numerous neurological diseases involving neuroinflammation, particularly microglia, contribute to neuronal death. Ferroptosis is implicated in various diseases characterized by neuronal injury. Studies showed that nicotinamide mononucleotide (NMN) inhibits both neuroinflammation and ferroptosis. However, the mechanisms of NMN in both ferroptosis and neuroinflammation remain unclear. We aimed to explore the effects of NMN on neuroinflammation and the susceptibility of microglia to ferroptosis. METHODS: Ferroptosis markers in macroglia exposed to lipopolysaccharides (LPS) were analyzed using CCK8, flow cytometry, ELISA, and quantitative RT-PCR. The effects of NMN on LPS-induced ferroptosis in microglia were evaluated through flow cytometry, western blot, and immunofluorescence staining. RT-PCR analysis assessed the inflammatory cytokine production of microglia subjected to Ferrostatin-1-regulated ferroptosis. RNA sequencing elucidated the underlying mechanism of NMN-involved microglia ferroptosis under LPS induction. In BV2 microglia, an inhibitor of GPX4, RSL3, was employed to suppress GPX4 expression. Intracerebroventricular injection of LPS was performed to evaluate neuroinflammation and microglia activation in vivo. RESULTS: NMN effectively rescued LPS-induced ferroptosis and improved cell viability in microglia. Co-administration of NMN and ferrostatin-1 significantly reduced proinflammatory cytokine production in microglia following the introduction of LPS stimuli. Mechanistically, NMN facilitated glutathione (GSH) production, and enhanced resistance to lipid peroxidation occurred in a manner dependent on GPX4, repressing cytokine transcription and protecting cells from ferroptosis. RNA sequencing elucidated the underlying mechanism of NMN-associated microglia ferroptosis under LPS induction. Furthermore, simultaneous injection of NMN ameliorated LPS-induced ferroptosis and neuroinflammation in mouse brains. The data from the present study indicated that NMN enhances GPX4-mediated ferroptosis defense against LPS-induced ferroptosis in microglia by recruiting GSH, thereby inhibiting neuroinflammation. CONCLUSION: Therapeutic approaches to effectively target ferroptosis in diseases using NMN, consideration should be given to both its anti-ferroptosis and anti-inflammatory effects to attain optimal outcomes, presenting promising strategies for treating neuroinflammation-related diseases or disorders.

The role of lipid peroxidation in epithelial-mesenchymal transition of retinal pigment epithelial cells.

Epithelial-Mesenchymal Transition (EMT) of retinal pigment epithelial (RPE) cells is recognized as pivotal in various retinal diseases. Previous studies have suggested a reciprocal regulation between reactive oxygen species (ROS) and EMT, though the involvement of peroxidized lipids or the effects of reducing them has remained unclear. The present study disclosed that EMT of ARPE-19 cells induced by TGF-ß2 and TNF-α involves increased lipid peroxidation, and Ferrostatin-1 (Fer-1), a lipophilic antioxidative agent, successfully inhibited the increase in lipid peroxidation. Fer-1 suppressed the formation of EMT-associated fibrotic deposits, while EMT induction or Fer-1 treatment did not influence the cell viability or proliferation. Functionally, Fer-1 impeded EMT-driven cell migration and reduction in transepithelial electrical resistance. It demonstrated regulatory prowess by downregulating the mesenchymal marker fibronectin, upregulating the epithelial marker ZO-1, and inhibiting the EMT-associated transcriptional factor ZEB1. Additionally, VEGF, a major pathogenic cytokine in various retinal diseases, is also upregulated during EMT, and Fer-1 significantly mitigated the effect. The present study disclosed the involvement of lipid peroxidation in EMT of RPE cells, and suggests the suppression of lipid peroxidation may be a potential therapeutic target in retinal diseases in which EMT is implicated.

Silencing of tropomodulin 1 inhibits acute myeloid leukemia cell proliferation and tumor growth by elevating karyopherin alpha 2-mediated autophagy.

Evidence shows that tropomodulin 1 (TMOD1) is a powerful diagnostic marker in the progression of several cancer types. However, the regulatory mechanism of TMOD1 in tumor progression is still unclear. Here, we showed that TMOD1 was highly expressed in acute myeloid leukemia (AML) specimens, and TMOD1-silencing inhibited cell proliferation by inducing autophagy in AML THP-1 and MOLM-13 cells. Mechanistically, the C-terminal region of TMOD1 directly bound to KPNA2, and TMOD1-overexpression promoted KPNA2 ubiquitylation and reduced KPNA2 levels. In contrast, TMOD1-silencing increased KPNA2 levels and facilitated the nuclear transfer of KPNA2, then subsequently induced autophagy and inhibited cell proliferation by increasing the nucleocytoplasmic transport of p53 and AMPK activation. KPNA2/p53 inhibitors attenuated autophagy induced by silencing TMOD1 in AML cells. Silencing TMOD1 also inhibited tumor growth by elevating KPNA2-mediated autophagy in nude mice bearing MOLM-13 xenografts. Collectively, our data demonstrated that TMOD1 could be a novel therapeutic target for AML treatment.

Effect of ferroptosis inhibitors in a murine model of acetaminophen-induced liver injury.

Liver injury caused by acetaminophen (APAP) overdose is the leading cause of acute liver failure in western countries. The mode of APAP-induced cell death has been controversially discussed with ferroptosis emerging as a more recent hypothesis. Ferroptosis is characterized by ferrous iron-catalyzed lipid peroxidation (LPO) causing cell death, which can be prevented by the lipophilic antioxidants ferrostatin-1 and UAMC-3203. To assess the efficacy of these ferroptosis inhibitors, we used two murine models of APAP hepatotoxicity, APAP overdose alone or in combination with FeSO4 in fasted male C57BL/6J mice. APAP triggered severe liver injury in the absence of LPO measured as hepatic malondialdehyde (MDA) levels. In contrast, ferrous iron co-treatment aggravated APAP-induced liver injury and caused extensive LPO. Standard doses of ferrostatin-1 did not affect MDA levels or the injury in both models. In contrast, UAMC-3203 partially protected in both models and reduced LPO in the presence of ferrous iron. However, UAMC-3203 attenuated the translocation of phospho-JNK through downregulation of the mitochondrial anchor protein Sab resulting in reduced mitochondrial dysfunction and liver injury. Thus, APAP toxicity does not involve ferroptosis under normal conditions. The lack of effects of ferroptosis inhibitors in the pathophysiology indicates that ferroptosis signaling pathways are not relevant therapeutic targets.

Ferrostatin-1 inhibits fibroblast fibrosis in keloid by inhibiting ferroptosis.

Background: Keloid is a chronic proliferative fibrotic disease caused by abnormal fibroblasts proliferation and excessive extracellular matrix (ECM) production. Numerous fibrotic disorders are significantly influenced by ferroptosis, and targeting ferroptosis can effectively mitigate fibrosis development. This study aimed to investigate the role and mechanism of ferroptosis in keloid development. Methods: Keloid tissues from keloid patients and normal skin tissues from healthy controls were collected. Iron content, lipid peroxidation (LPO) level, and the mRNA and protein expression of ferroptosis-related genes including solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), transferrin receptor (TFRC), and nuclear factor erythroid 2-related factor 2 (Nrf2) were determined. Mitochondrial morphology was observed using transmission electron microscopy (TEM). Keloid fibroblasts (KFs) were isolated from keloid tissues, and treated with ferroptosis inhibitor ferrostatin-1 (fer-1) or ferroptosis activator erastin. Iron content, ferroptosis-related marker levels, LPO level, mitochondrial membrane potential, ATP content, and mitochondrial morphology in KFs were detected. Furthermore, the protein levels of α-smooth muscle actin (α-SMA), collagen I, and collagen III were measured to investigate whether ferroptosis affect fibrosis in KFs. Results: We found that iron content and LPO level were substantially elevated in keloid tissues and KFs. SLC7A11, GPX4, and Nrf2 were downregulated and TFRC was upregulated in keloid tissues and KFs. Mitochondria in keloid tissues and KFs exhibited ferroptosis-related pathology. Fer-1 treatment reduced iron content, restrained ferroptosis and mitochondrial dysfunction in KFs, Moreover, ferrostatin-1 restrained the protein expression of α-SMA, collagen I, and collagen III in KFs. Whereas erastin treatment showed the opposite results. Conclusion: Ferroptosis exists in keloid. Ferrostatin-1 restrained ECM deposition and fibrosis in keloid through inhibiting ferroptosis, and erastin induced ECM deposition and fibrosis through intensifying ferroptosis.

Blood brain barrier-targeted lipid nanoparticles improved the neuroprotection of Ferrostatin-1 against cerebral ischemic damage in an experimental stroke model.

Cerebral ischemic stroke is a serious disease with high mortality and disability rates. However, few neuroprotective drugs have been used for ischemic stroke in the clinic. Two main reasons may be responsible for this failure: difficulty in penetrating the blood-brain barrier (BBB) and easily inactivated in the blood circulation. Ferroptosis, a lipid oxidation-related cell death, plays significant roles in cerebral ischemia-reperfusion injury. We utilized RVG29, a peptide derived from Rabies virus glycoprotein, to obtain BBB-targeted lipid nanoparticles (T-LNPs) in order to investigate whether T-LNPs improved the neuroprotective effects of Ferrostatin-1 (Fer1, an inhibitor of ferroptosis) against cerebral ischemic damage. T-LNPs significantly increased BBB penetration following oxygen/glucose deprivation exposure in an in vitro BBB model and enhanced the fluorescence distribution in brain tissues at 6 h post-administration in a cerebral ischemic murine model. Moreover, T-LNPs encapsulated Fer1 (T-LNPs-Fer1) significantly enhanced the inhibitory effects of Fer1 on ferroptosis by maintaining the homeostasis of NADPH oxidase 4 (NOX4) and glutathione peroxidase 4 (GPX4) signals in neuronal cells after cerebral ischemia. T-LNPs-Fer1 significantly suppressed oxidative stress [heme oxygenase-1 expression and malondialdehyde (the product of lipid ROS reaction)] in neurons and alleviated ischemia-induced neuronal cell death, compared to Fer1 alone without encapsulation. Furthermore, T-LNPs-Fer1 significantly reduced cerebral infarction and improved behavior functions compared to Fer1-treated cerebral ischemic mice after 45-min ischemia/24-h reperfusion. These findings showed that the T-LNPs helped Fer1 penetrate the BBB and improved the neuroprotection of Fer1 against cerebral ischemic damage in experimental stroke, providing a feasible translational strategy for the development of clinical drugs for the treatment of ischemic stroke.

Shen-Qi-Ling-Bi Decoction Inhibits Colorectal Cancer Cell Growth by Inducing Ferroptosis Through Inactivation of PI3K/AKT Signaling Pathway.

Colorectal cancer (CRC) is a common malignancy with poor prognosis. Shen-Qi-Ling-Bi Decoction (SQLB), a classic traditional Chinese medicine (TCM) formula, was found to exert antitumor effects in CRC. This study aimed to explore the biological functions of SQLB in CRC. Cell Counting Kit 8 (CCK-8), wound healing, and transwell invasion assays in vitro were used to evaluate the antitumor effects of SQLB in CRC cells. In addition, ferroptosis in CRC cells was determined by evaluating Fe2+ content and lipid ROS, MDA, and GSH levels. SQLB treatment partially reduced CRC cell proliferation, migration, and invasion; however, a ferroptosis inhibitor, ferrostatin-1 (Fer-1), abolished these effects. In addition, SQLB treatment triggered CRC cell ferroptosis, as evidenced by increased Fe2+, lipid ROS, and MDA levels and decreased GSH levels; conversely, these levels were reversed by Fer-1. Furthermore, SQLB notably suppressed tumor growth in nude mice in vivo. Meanwhile, SQLB decreased phosphorylated PI3K and AKT levels, downregulated Nrf2, GPX4, and SLC7A11 levels, and upregulated ACSL4 levels in CRC cells and in tumor tissues; however, these effects were reversed by Fer-1. Collectively, SQLB inhibited CRC cell proliferation, invasion, and migration by triggering ferroptosis through inactivation of the PI3K/AKT signaling pathway. These findings demonstrate a novel mechanism of action for SQLB in the treatment of CRC.

Fer-1 Protects against Isoflurane-Induced Ferroptosis in Astrocytes and Cognitive Impairment in Neonatal Mice.

Early and prolonged exposure to anesthetic agents could cause neurodevelopmental disorders in children. Astrocytes, heavily outnumber neurons in the brain, are crucial regulators of synaptic formation and function during development. However, how general anesthetics act on astrocytes and the impact on cognition are still unclear. In this study, we investigated the role of ferroptosis and GPX4, a major hydroperoxide scavenger playing a pivotal role in suppressing the process of ferroptosis, and their underlying mechanism in isoflurane-induced cytotoxicity in astrocytes and cognitive impairment. Our results showed that early 6 h isoflurane anesthesia induced cognitive impairment in mice. Ferroptosis-relative genes and metabolic changes were involved in the pathological process of isoflurane-induced cytotoxicity in astrocytes. The level of GPX4 was decreased while the expression of 4-HNE and generation of ROS were elevated after isoflurane exposure. Selectively blocking ferroptosis with Fer-1 attenuated the abovementioned cytotoxicity in astrocytes, paralleling with the reverse of the changes in GPX4, ROS and 4-HNE secondary to isoflurane anesthesia. Fer-1 attenuated the cognitive impairment induced by prolonged isoflurane exposure. Thus, ferroptosis conduced towards isoflurane-induced cytotoxicity in astrocytes via suppressing GPX4 and promoting lipid peroxidation. Fer-1 was expected to be an underlying intervention for the neurotoxicity induced by isoflurane in the developing brain, and to alleviate cognitive impairment in neonates.

The protective effects of Ferrostatin-1 against inflammation-induced preterm birth and fetal brain injury.

INTRODUCTION: Recent studies have suggested the involvement of ferroptosis in preterm birth. Despite compelling evidence, the underlying mechanism remains unknown. This investigation aimed to determine the therapeutic effects of Ferrostatin-1 (Fer-1), an inhibitor of ferroptosis, in preterm birth and fetal brain injury. METHODS: Human placenta samples and clinical data of participants were collected to ascertain whether placental ferroptosis was associated with preterm birth. Lipopolysaccharide (LPS)-induced preterm birth mouse model was used to examine the protective effects of Fer-1 on preterm birth. Fetal brain tissues and offspring mice at 5 and 8 weeks were studied to determine the effects of Fer-1 on the cognitive function of offspring. RESULTS: We examined the mechanism of spontaneous preterm birth and discovered that placental ferroptosis was associated with preterm birth. Fer-1 inhibited preterm birth by ameliorating placental ferroptosis and maternal inflammation, thus improving LPS-induced intrauterine inflammation to maintain pregnancy. Antenatal administration of Fer-1 prevented LPS-induced fetal brain damage in the acute phase and improved long-term neurodevelopmental impairments by improving placental neuroendocrine signaling and maintaining placental function. CONCLUSION: Fer-1 inhibited preterm birth and fetal brain injury by inhibiting maternal inflammation and improving placental function. Our findings provide a novel therapeutic strategy for preterm birth.

AURKA knockdown inhibits esophageal squamous cell carcinoma progression through ferroptosis.

Aurora kinase A, as a pro-carcinogenic in gastric cancer and glioma kinase, is enhanced in several human tumors. However, it's regulatory mechanism in esophageal squamous cell carcinoma (ESCC) remains unclear. Thus, this study aimed to investigate the expression status, functional roles, and molecular mechanisms of AURKA in ESCC development. AURKA expression was analyzed by the screening of the GEO database and detected using an immunohistochemical method. The biological function of AURKA on ESCC was evaluated in vitro and in vivo. Western blot assay, malondialdehyde (MDA), iron, and glutathione (GSH) kits were utilized to assess changes in ferroptosis. Database analysis results showed that AURKA was a differential gene in ESCC and was highly expressed in human ESCC tissues. Functionally, AURKA knockdown decreased ESCC cell proliferation, invasion, and metastasis both in vitro and in vivo. Moreover, when AURKA was knockdown, cells were more correctly blocked in the G2/M phase, and the ferroptosis-related MDA and Fe increased, whereas the GSH reduced. Consistently, Glutathione peroxidase 4 (GPX4) and solute carrier family 7a member 11 (SLC7A11) expression were downregulated by AURKA knockdown. However, ferroptosis inhibitor partially restore ESCC cell proliferation, invasion, and metastasis caused by AURKA knockdown. AURKA knockdown enhances ferroptosis and acts against cancer progression in ESCC. AURKA acts as a tumor-promoting gene and may serve as potential target for ESCC treatment.

Design, synthesis, and evaluation of formylpiperazine analogs of Ferrostatin-1 as novel improved ferroptosis inhibitors.

In this study, a series of new formylpiperazine-derived ferroptosis inhibitors were designed and synthesized based on the structure of a known ferroptosis inhibitor, ferrostatin-1 (Fer-1). The anti-ferroptosis activity of these synthetic compounds in human umbilical vein endothelial cells (HUVECs) induced by Erastin was evaluated. It was found that some of the new compounds, especially compound 26, showed potent anti-ferroptosis activity, as evidenced by its ability to restore cell viability, reduce iron accumulation, scavenge reactive oxygen species, maintain mitochondrial membrane potential, increase GSH levels, decrease LPO and MDA content, and upregulate GPX4 expression. Moreover, compound 26 exhibited superior microsomal stability than Fer-1. The present results suggest that compound 26 is a promising lead compound for the development of new ferroptosis inhibitors for the treatment of vascular diseases.

Cpd-A1 alleviates acute kidney injury by inhibiting ferroptosis.

Acute kidney injury (AKI) is defined as sudden loss of renal function characterized by increased serum creatinine levels and reduced urinary output with a duration of 7 days. Ferroptosis, an iron-dependent regulated necrotic pathway, has been implicated in the progression of AKI, while ferrostatin-1 (Fer-1), a selective inhibitor of ferroptosis, inhibited renal damage, oxidative stress and tubular cell death in AKI mouse models. However, the clinical translation of Fer-1 is limited due to its lack of efficacy and metabolic instability. In this study we designed and synthesized four Fer-1 analogs (Cpd-A1, Cpd-B1, Cpd-B2, Cpd-B3) with superior plasma stability, and evaluated their therapeutic potential in the treatment of AKI. Compared with Fer-1, all the four analogs displayed a higher distribution in mouse renal tissue in a pharmacokinetic assay and a more effective ferroptosis inhibition in erastin-treated mouse tubular epithelial cells (mTECs) with Cpd-A1 (N-methyl-substituted-tetrazole-Fer-1 analog) being the most efficacious one. In hypoxia/reoxygenation (H/R)- or LPS-treated mTECs, treatment with Cpd-A1 (0.25 µM) effectively attenuated cell damage, reduced inflammatory responses, and inhibited ferroptosis. In ischemia/reperfusion (I/R)- or cecal ligation and puncture (CLP)-induced AKI mouse models, pre-injection of Cpd-A1 (1.25, 2.5, 5 mg·kg-1·d-1, i.p.) dose-dependently improved kidney function, mitigated renal tubular injury, and abrogated inflammation. We conclude that Cpd-A1 may serve as a promising therapeutic agent for the treatment of AKI.

Endometrial stem cells alleviate cisplatin-induced ferroptosis of granulosa cells by regulating Nrf2 expression.

BACKGROUND: Premature ovarian failure (POF) caused by cisplatin is a severe and intractable sequela for young women with cancer who received chemotherapy. Cisplatin causes the dysfunction of granulosa cells and mainly leads to but is not limited to its apoptosis and autophagy. Ferroptosis has been also reported to participate, while little is known about it. Our previous experiment has demonstrated that endometrial stem cells (EnSCs) can repair cisplatin-injured granulosa cells. However, it is still unclear whether EnSCs can play a repair role by acting on ferroptosis. METHODS: Western blotting and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were applied to detect the expression levels of ferroptosis-related genes. CCK-8 and 5-Ethynyl-2'-deoxyuridine (EdU) assays were used to evaluate cell viability. Transmission electron microscopy (TEM) was performed to detect ferroptosis in morphology. And the extent of ferroptosis was assessed by ROS, GPx, GSSG and MDA indicators. In vivo, ovarian morphology was presented by HE staining and the protein expression in ovarian tissue was detected by immunohistochemistry. RESULTS: Our results showed that ferroptosis could occur in cisplatin-injured granulosa cells. Ferroptosis inhibitor ferrostatin-1 (Fer-1) and EnSCs partly restored cell viability and mitigated the damage of cisplatin to granulosa cells by inhibiting ferroptosis. Moreover, the repair potential of EnSCs can be markedly blocked by ML385. CONCLUSION: Our study demonstrated that cisplatin could induce ferroptosis in granulosa cells, while EnSCs could inhibit ferroptosis and thus exert repair effects on the cisplatin-induced injury model both in vivo and in vitro. Meanwhile, Nrf2 was validated to participate in this regulatory process and played an essential role.

Alpha-synuclein interaction with mitochondria is the final mechanism of ferroptotic death induced by erastin in SH-SY5Y cells.

Ferroptosis has been characterized as a form of iron-dependent regulated cell death accompanied by an accumulation of reactive oxygen species and lipid oxidation products along with typical morphological alterations in mitochondria. Ferroptosis is activated by diverse triggers and inhibited by ferrostatin-1 and liproxstatin-1, apart from iron chelators and several antioxidants, and the process is implicated in multiple pathological conditions. There are, however, certain ambiguities about ferroptosis, especially regarding the final executioner of cell death subsequent to the accumulation of ROS. This study uses a typical inducer of ferroptosis such as erastin on SH-SY5Y cells, and shows clearly that ferroptotic death of cells is accompanied by the loss of mitochondrial membrane potential and intracellular ATP content along with an accumulation of oxidative stress markers. All these are prevented by ferrostatin-1 and liproxstatin-1. Additionally, cyclosporine A prevents mitochondrial alterations and cell death induced by erastin implying the crucial role of mitochondrial permeability transition pore (mPTP) activation in ferroptotic death. Furthermore, an accumulation of α-synuclein occurs during erastin induced ferroptosis which can be inhibited by ferrostatin-1 and liproxstatin-1. When the knock-down of α-synuclein expression is performed by specific siRNA treatment of SH-SY5Y cells, the mitochondrial impairment and ferroptotic death of the cells induced by erastin are markedly prevented. Thus, α-synuclein through the involvement of mPTP appears to be the key executioner protein of ferroptosis induced by erastin, but it needs to be verified if it is a generalized mechanism of ferroptosis by using other inducers and cell lines.

Ferrostatin­1 alleviates liver injury via decreasing ferroptosis following ricin toxin poisoning in rat.

Ricin is a highly toxic plant toxin that can cause multi-organ failure, especially liver dysfunction, and is a potential bioterrorism agent. Despite the serious public health challenge posed by ricin, effective therapeutic for ricin-induced poisoning is currently unavailable. Therefore, it is important to explore the mechanism of ricin poisoning and develop appropriate treatment protocols accordingly. Previous studies have shown that lipid peroxidation and iron accumulation are associated with ricin poisoning. Ferroptosis is an iron-dependent form of cell death caused by excessive accumulation of lipid peroxide. The role and mechanism of ferroptosis in ricin poisoning are unclear and require further study. We investigated the effect of ferroptosis on ricin-induced liver injury and further elucidated the mechanism. The results showed that ferroptosis occurred in the liver of ricin-intoxicated rats, and Ferrostatin­1 could ameliorate hepatic ferroptosis and thus liver injury. Ricin induced liver injury by decreasing hepatic reduced glutathione and the protein level of glutathione peroxidase 4 and Solute Carrier Family 7 Member 11, increasing iron, malondialdehyde and reactive oxygen species, and mitochondrial damage, whereas Ferrostatin­1 pretreatment increased hepatic reduced glutathione and the protein level of glutathione peroxidase 4 and Solute Carrier Family 7 Member 11, decreased iron, malondialdehyde, and reactive oxygen species, and ameliorated mitochondrial damage, thereby alleviated liver injury. These results suggested that ferroptosis exacerbated liver injury after ricin poisoning and that inhibition of ferroptosis may be a novel strategy for the treatment of ricin poisoning.

Protecting against ferroptosis in hyperuricemic nephropathy: The potential of ferrostatin-1 and its inhibitory effect on URAT1.

Hyperuricemic nephropathy (HN) is characterized by renal fibrosis and tubular necrosis caused by elevated uric acid levels. Ferroptosis, an iron-dependent type of cell death, has been implicated in the pathogenesis of kidney diseases. The objective of this study was to explore the role of ferroptosis in HN and the impact of a ferroptosis inhibitor, ferrostatin-1 (Fer-1). The study combined adenine and potassium oxonate administration to establish a HN model in mice and treated HK-2 cells with uric acid to simulate HN conditions. The effects of Fer-1 on the renal function, fibrosis, and ferroptosis-associated molecules were investigated in HN mice and HK-2 cells treated with uric acid. The HN mice presented with renal dysfunction characterized by elevated tissue iron levels and diminished antioxidant capacity. There was a significant decrease in the mRNA and protein expression levels of SLC7A11, GPX4, FTL-1 and FTH-1 in HN mice. Conversely, treatment with Fer-1 reduced serum uric acid, serum creatinine, and blood urea nitrogen, while increasing uric acid levels in urine. Fer-1 administration also ameliorated renal tubule dilatation and reduced renal collagen deposition. Additionally, Fer-1 also upregulated the expression levels of SLC7A11, GPX4, FTL-1, and FTH-1, decreased malondialdehyde and iron levels, and enhanced glutathione in vivo and in vitro. Furthermore, we first found that Fer-1 exhibited a dose-dependent inhibition of URAT1, with the IC50 value of 7.37 ± 0.66 µM. Collectively, the current study demonstrated that Fer-1 effectively mitigated HN by suppressing ferroptosis, highlighting the potential of targeting ferroptosis as a therapeutic strategy for HN.

Sodium Butyrate Alleviates Free Fatty Acid-Induced Steatosis in Primary Chicken Hepatocytes via Regulating the ROS/GPX4/Ferroptosis Pathway.

Fatty liver hemorrhagic syndrome (FLHS) in laying hens is a nutritional metabolic disease commonly observed in high-yielding laying hens. Sodium butyrate (NaB) and ferroptosis were reported to contribute to the pathogenesis of fatty liver-related diseases. However, the underlying mechanism of NaB in FLHS and whether it mediates ferroptosis remains unclear. A chicken primary hepatocyte induced by free fatty acids (FFAs, keeping the ratio of sodium oleate and sodium palmitate concentrations at 2:1) was established, which received treatments with NaB, the ferroptosis inducer RAS-selective lethal 3 (RSL3), and the inhibitor ferrostatin-1 (Fer-1). As a result, NaB increased biochemical and lipid metabolism indices, and the antioxidant level, while inhibiting intracellular ROS accumulation and the activation of the ferroptosis signaling pathway, as evidenced by a reduction in intracellular iron concentration, upregulated GPX4 and xCT expression, and inhibited NCOA4 and ACSL4 expression. Furthermore, treatment with Fer-1 reinforced the protective effects of NaB, while RSL3 reversed it by blocking the ROS/GPX4/ferroptosis pathway, leading to the accumulation of lipid droplets and oxidative stress. Collectively, our findings demonstrated that NaB protects hepatocytes by regulating the ROS/GPX4-mediated ferroptosis pathway, providing a new strategy and target for the treatment of FLHS.

Ferrostatin 1 ameliorates UVB-induced damage of HaCaT cells by regulating ferroptosis.

Ferroptosis, a type of programmed cell death, occurs when there is oxidative stress and lipid peroxides. This condition is marked by lipid peroxidation that relies on iron and the reduction of cellular defences against oxidation. To investigate the effect of UVB irradiation on ferroptosis of human keratinocytes HaCaT cells, the cells were pretreated with Ferrostatin 1 (Fer-1, 10 µM), an ferroptosis inhibitor and then irradiated with UVB (20 mJ/cm2 ) for 30 min to detect related indexes of ferroptosis through MTT assay, quantitative real-time polymerase chain reaction, flow cytometry, reactive oxygen species (ROS) assay, western blotting. Results showed that UVB significantly reduced cell activity, promoted apoptosis and ROS level, whereas Fer-1 significantly increased cell activity, and reduced apoptosis and ROS level. In addition, UVB significantly reduced levels of ferroptosis-related proteins and skin barrier-related proteins, and increased levels of γ-H2AX and iron, whereas Fer-1 significantly increased their protein levels, and reduced levels of γ-H2AX and iron. Conjoint analysis of transcriptomic and proteomic revealed that UVB significantly reduced the levels of TIMP metallopeptidase inhibitor 3 (TIMP3), and coagulation factor II thrombin receptor (F2R), whereas Fer-1 significantly promoted the levels of TIMP3, and F2R. Therefore, our results indicated that Fer-1 significantly ameliorates UVB-induced damage of HaCaT cells by regulating the levels of TIMP3 and F2R.

Inhibition of ferroptosis reverses heart failure with preserved ejection fraction in mice.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) accounts for approximately 50% of heart failure cases. The molecular mechanisms by which HFpEF leads to impaired diastolic function of the heart have not been clarified, nor have the drugs that target the clinical symptoms of HFpEF patients. METHODS: HFpEF chip data (GSE180065) was downloaded from the National Center for Biotechnology Information (NCBI) database. Differentially expressed genes (DEGs) were filtered by the limma package in R and processed for GO and KEGG pathway analyses. Then, ferroptosis-related genes in HFpEF were identified by taking the intersection between DEGs and ferroptosis-related genes. CytoHubba and MCODE were used to screen ferroptosis-related hub DEGs in the protein-protein interaction (PPI) network. Establishment of a mouse HFpEF model to validate the transcript levels of ferroptosis-related hub DEGs and ferroptosis-related phenotypes. Transcript levels of ferroptosis-related hub DEGs and HFpEF phenotypic changes in the hearts of HFpEF mice were further examined after the use of ferroptosis inhibitors. RESULTS: GO and KEGG enrichment analyses suggested that the DEGs in HFpEF were significantly enriched in ferroptosis-related pathways. A total of 24 ferroptosis-related DEGs were identified between the ferroptosis gene dataset and the DEGs. The established PPI network was further analyzed by CytoHubba and MCODE modules, and 11 ferroptosis-related hub DEGs in HFpEF were obtained. In animal experiments, HFpEF mice showed significant abnormal activation of ferroptosis. The expression trends of the 11 hub DEGs associated with ferroptosis, except for Cdh1, were consistent with the results of the bioinformatics analysis. Inhibition of ferroptosis alters the transcript levels of 11 ferroptosis-related hub DEGs and ameliorates HFpEF phenotypes. CONCLUSIONS: The present study contributes to a deeper understanding of the specific mechanisms by which ferroptosis is involved in the development of HFpEF and suggests that inhibition of ferroptosis may mitigate the progression of HFpEF. In addition, eleven hub genes were recognized as potential drug binding targets.