Acyl-CoA synthetase long chain family member 4 plays detrimental role in early brain injury after subarachnoid hemorrhage in rats by inducing ferroptosis

VEGFD/VEGFR3 signaling contributes to the dysfunction of the astrocyte IL-3/microglia IL-3Rα cross-talk and drives neuroinflammation in mouse ischemic stroke

Astrocyte-derived IL-3 activates the corresponding receptor IL-3Rα in microglia. This cross-talk between astrocytes and microglia ameliorates the pathology of Alzheimer's disease in mice. In this study we investigated the role of IL-3/IL-3Rα cross-talk and its regulatory mechanisms in ischemic stroke. Ischemic stroke was induced in mice by intraluminal occlusion of the right middle cerebral artery (MCA) for 60 min followed by reperfusion (I/R). Human astrocytes or microglia subjected to oxygen-glucose deprivation and reoxygenation (OGD/Re) were used as in vitro models of brain ischemia. We showed that both I/R and OGD/Re significantly induced decreases in astrocytic IL-3 and microglial IL-3Rα protein levels, accompanied by pro-inflammatory activation of A1-type astrocytes and M1-type microglia. Importantly, astrocyte-derived VEGFD acting on VEGFR3 of astrocytes and microglia contributed to the cross-talk dysfunction and pro-inflammatory activation of the two glial cells, thereby mediating neuronal cell damage. By using metabolomics and multiple biochemical approaches, we demonstrated that IL-3 supplementation to microglia reversed OGD/Re-induced lipid metabolic reprogramming evidenced by upregulated expression of CPT1A, a rate-limiting enzyme for the mitochondrial β-oxidation, and increased levels of glycerophospholipids, the major components of cellular membranes, causing reduced accumulation of lipid droplets, thus reduced pro-inflammatory activation and necrosis, as well as increased phagocytosis of microglia. Notably, exogenous IL-3 and the VEGFR antagonist axitinib reestablished the cross-talk of IL-3/IL-3Rα, improving microglial lipid metabolic levels via upregulation of CPT1A, restoring microglial phagocytotic function and attenuating microglial pro-inflammatory activation, ultimately contributing to brain recovery from I/R insult. Our results demonstrate that VEGFD/VEGFR3 signaling contributes to the dysfunction of the astrocyte IL-3/microglia IL-3Rα cross-talk and drives pro-inflammatory activation, causing lipid metabolic reprogramming of microglia. These insights suggest VEGFR3 antagonism or restoring IL-3 levels as a potential therapeutic strategy for ischemic stroke.

The role of ferroptosis and oxidative stress in cognitive deficits among chronic schizophrenia patients: a multicenter investigation

Oxidative stress (OS) is crucial in schizophrenia (SCZ) pathology. Ferroptosis, a recently discovered cell death pathway linked to OS, might contribute to the development of SCZ. This study investigated the association between ferroptosis markers and cognitive impairments in chronic SCZ patients. A retrospective analysis was conducted on 204 chronic SCZ patients with cognitive deficits and 216 healthy controls (HC) matched for relevant characteristics. Plasma levels of ferroptosis and OS markers, including iron, ferritin (FE), transferrin (TF), glutathione peroxidase 4 (GPX4), long-chain acyl-CoA synthetase 4 (ACSL4), glutathione (GSH), sirtuin 1 (SIRT1), nuclear factor erythroid 2-related factor 2 (Nrf2), malondialdehyde (MDA), and superoxide dismutase (SOD) were measured. Standardized assessments like the positive and negative syndrome scale (PANSS), and Montreal Cognitive Assessment (MoCA) were used to evaluate psychiatric symptoms, and cognitive function. SCZ patients showed significant differences in markers compared to the HC group (P < 0.01). Multiple linear regression analysis revealed that decreased GSH and iron levels, along with elevated SOD levels, were significantly associated with the overall severity of psychiatric symptoms. Additionally, reduced GPX4 levels and increased ACSL4 and FE levels were significantly linked to negative symptoms and cognitive impairments. Notably, GPX4 emerged as a key predictor for cognitive function in abstraction and language domains. Our study revealed alterations in the altered plasma levels of GPX4, GSH, iron, ACSL4, FE, and SOD in chronic SCZ patients, which might indicate a close association between biomarkers of ferroptosis and OS and the psychiatric symptoms and cognitive deficits observed in these individuals.

Asiatic acid alleviates subarachnoid hemorrhage-induced brain injury in rats by inhibiting ferroptosis of neurons via targeting acyl-coenzyme a oxidase 1

The occurrence of subarachnoid hemorrhage (SAH) can lead to brain injury, which is a fatal condition with limited effective clinical intervention strategies. The naturally occurring component Asiatic acid (AA), found in the tropical plant Centella asiatica, has been reported to possess neuroprotective properties. The objective of this study was to evaluate the neuroprotective effect of AA following SAH and investigate its potential mechanisms. The SAH model was established in male Sprague-Dawley (SD) rats through intravascular perforation, following a standardized protocol. The administration of AA was performed via gavage following SAH. A lentiviral vector was constructed and utilized for the knockdown of Acyl Coenzyme A Oxidase 1 (ACOX1) Firstly, AA treatment effectively improves brain neurological deficit, neuronal damage, and iron deposition induced by SAH. Furthermore, it has been demonstrated that AA directly interacts with ACOX1, which exhibits decreased expression in neurons following SAH. Additionally, our study reveals AA can reverse SAH-induced reduction in ACOX1 expression, concurrently ameliorating neuronal ferroptosis. This improvement is evidenced by reduced lipid peroxidation, including mitigated GSH depletion, decreased MDA production, and increased GPX4 content and activity. Also, AA enhances mitochondrial constriction while alleviating cristae disruption induced by SAH, providing crucial insights into its neuroprotective effects against neuronal ferroptosis in SAH. Moreover, when ACOX1 is knocked down, the neuroprotective effects of AA are weakened. Collectively, this study elucidated the neuroprotective effect of AA by inhibiting neuronal cell ferroptosis through targeting ACOX1. These findings suggest that AA holds promise as a potential therapeutic candidate for ameliorating SAH-induced brain injury.

Update on Strategies to Reduce Early Brain Injury after Subarachnoid Hemorrhage

PURPOSE OF REVIEW

Early brain injury (EBI) after aneurysmal subarachnoid hemorrhage (SAH) is the most influential clinical determinant of outcomes. Despite significant advances in understanding of the pathophysiology of EBI, currently no treatments to target EBI have been developed. This review summarizes recent advances in EBI research over the past five years with a focus on potential therapeutic targets.

RECENT FINDINGS

Mechanism-specific translational studies are converging on several pathophysiologic pathways: improved antioxidant delivery and the Sirt1/Nrf2 pathway for reactive oxygen species; NLRP3 inflammasome and microglial polarization for inflammation; and the PI3K/Akt pathway for apoptosis. Recently identified mechanistic components, such as microcirculatory failure and ferroptosis, need particular attention. Clinical studies developing radiographic markers and mechanism-specific, biofluid markers are attempting to bridge the translational therapeutic gap. There has been an exponential growth in EBI research. Further clinical studies which address specific pathophysiology mechanisms need to be performed to identify novel therapeutic approaches.

[Ferroptosis and liver diseases]

As the central organ of metabolism, the liver plays a pivotal role in the regulation of the synthesis and metabolism of various nutrients within the body. Ferroptosis, as a newly discovered type of programmed cell death caused by the accumulation of iron-dependent lipid peroxides, is involved in the physiological and pathological processes of a variety of acute and chronic liver diseases. Ferroptosis can accelerate the pathogenetic process of acute liver injury, metabolic associated fatty liver disease, alcoholic liver disease, viral hepatitis, and autoimmune hepatitis; while it can slower disease progression in advanced liver fibrosis and hepatocellular carcinoma. This suggests that targeted regulation of ferroptosis may impact the occurrence and development of various liver diseases. This article reviews the latest research progress of ferroptosis in various liver diseases, including acute liver injury, metabolic associated fatty liver disease, alcoholic liver disease, viral hepatitis, autoimmune hepatitis, liver fibrosis and hepatocellular carcinoma. It aims to provide insights for the prevention and treatment of acute and chronic liver diseases through targeting ferroptosis.

The ameliorative effects of melatonin against BDE-47-induced hippocampal neuronal ferroptosis and cognitive dysfunction through Nrf2-Chaperone-mediated autophagy of ACSL4 degradation

Recent studies demonstrate that lipid peroxidation-induced ferroptosis participates in 2,2',4,4'-tetrabromodiphenyl ether (BDE-47)-evoked neurotoxicity and cognitive dysfunction. Melatonin has been indicated to confer neuroprotection against brain diseases via its potent anti-ferroptotic effects. Therefore, this study aims to explore whether melatonin can mitigate BDE-47-elicited cognitive impairment via suppressing ferroptosis, and further delineate the underlying mechanisms. Our results found that melatonin administration effectively inhibited BDE-47-induced ferroptosis in mice hippocampi and murine hippocampal neuronal HT-22 cells. Acyl-CoA synthetase long-chain family member 4 (ACSL4), a key lipid metabolism enzyme dictating ferroptosis sensitivity, accompanied by higher MDA and lipid reactive oxygen species (ROS), was remarkably increased under BDE-47 stress, while melatonin supplementation could suppress the elevated ACSL4 in vivo and in vitro. Furthermore, melatonin facilitated lysosomal ACSL4 degradation through enhancing lysosome-associated membrane protein type 2a (LAMP2a) expression and chaperone-mediated autophagy (CMA) activity, while LAMP2a knockdown abrogated the positive effects of melatonin on ACSL4 elimination in BDE-47-treated HT-22 cells. Moreover, nuclear factor erythroid 2-related factor 2 (Nrf2) activation by melatonin contributed to LAMP2a upregulation and CMA of ACSL4 and subsequent neuronal ferroptosis. Importantly, melatonin, CMA activator CA77.1, and ACSL4 inhibitor rosiglitazone (RSG) administration substantially attenuated neuronal/synaptic injury and cognitive deficits following BDE-47 exposure. Taken together, these findings revealed that melatonin could prevent BDE-47-provoked ferroptosis in the hippocampal neurons and mitigate cognitive dysfunction by facilitating ACSL4 degradation via Nrf2-chaperone-mediated autophagy. Therefore, melatonin might be a potential candidate for treating BDE-47-elicited neurotoxicity and neurobehavioral disorder.

Celastrol alleviates secondary brain injury following intracerebral haemorrhage by inhibiting neuronal ferroptosis and blocking blood-brain barrier disruption

Background

Following recent research advancements, an increasing level of evidence had been published to indicate that celastrol exerted a therapeutic effect on a range of nervous system diseases. This study therefore aimed to investigate the potential involvement of celastrol on ferroptosis and the blood-brain barrier disruption in intracerebral haemorrhage.

Methods

We established a rat intracerebral haemorrhage and adrenal pheochromocytoma cell (PC12) OxyHb models using an ACSL4 overexpression vector. Ferroptosis-related indices were assessed using corresponding assay kits, and immunofluorescence and flow cytometry were used to measure reactive oxygen species (ROS) levels. Additionally, quantitative PCR (qPCR) and western blot analyses were conducted to evaluate the expression of key proteins and elucidate the role of celastrol in intracerebral haemorrhage (ICH).

Results

Celastrol significantly improved neurological function scores, blood-brain barrier integrity, and brain water content in rats with ICH. Moreover, subsequent analysis of ferroptosis-related markers, such as Fe2+, ROS, MDA, and SOD, suggested that celastrol exerted a protective effect against the oxidative damage induced by ferroptosis in ICH rats and cells. Furthermore, Western blotting indicated that celastrol attenuated ferroptosis by modulating the expression levels of key proteins, including acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), and anti-transferrin receptor 1 (TFR1) both in vitro and in vivo. ACSL4 overexpression attenuated the neuroprotective effects of celastrol on ICH in vitro. Molecular docking analysis revealed that celastrol interacted with ACSL4 via the GLU107, GLN109, ASN111, and LYS357 binding sites.

Conclusions

Celastrol exerted antioxidant properties and aids in neurological recovery after stroke by suppressing ACSL4 expression during ferroptosis. As such, this drug represented a promising pharmaceutical candidate for the treatment of ICH.

Fibronectin type III domain containing protein 5/irisin alleviated sepsis-induced acute kidney injury by abating ferroptosis through the adenosine 5'-monophosphate-activated protein kinase/nuclear factor erythroid-2-related factor 2 signaling pathway

Objective

Ferroptosis has been described in association with acute kidney injury (AKI)-induced sepsis. Fibronectin type III domain containing protein 5 (FNDC5)/irisin plays a crucial role in renal protection. The objective of this study was to investigate whether FNDC5/irisin is involved in AKI-induced sepsis by modulating ferroptosis, and the molecular mechanisms that may be involved.

Material and Methods

A sepsis-induced AKI model was built in vivo and in vitro through lipopolysaccharide (LPS) intervention. FNDC5, adenosine 5'-monophosphate-activated protein kinase (AMPK), phospho-AMPK (p-AMPK), nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), glutathione peroxidase 4 (GPX4), and acyl-CoA synthetase long-chain family member 4 (ACSL4) concentrations in cells and mouse kidney tissues were appraised by Western blot. Pro-inflammatory cytokines concentrations in cell supernatants and mouse kidney tissues were appraised by enzyme-linked immunosorbent assay. Fe2+ concentration in cells and mouse kidney tissue was appraised by kit. The apoptosis rate of cells and mouse kidney tissue was measured by flow cytometry. Automatic biochemical analyzer was to test serum creatinine (SCr) and blood urea nitrogen (BUN). The kidney tissue sections from each groups were observed by hematoxylin and eosin staining.

Results

LPS abated FNDC5 concentration in human kidney-2 cells and mouse kidney tissue (P < 0.001). Overexpression of FNDC5 can abated proinflammatory cytokines concentrations in cells and mouse kidney tissue (P < 0.01). Meanwhile, overexpression of FNDC5 can boost GPX4 protein concentration, abate ACSL4 protein, and abate Fe2+ concentration in cells and mouse kidney tissues (P < 0.05). In addition, the overexpression of FNDC5 can reduce the rate of apoptosis (P < 0.01). In vivo experiments showed that FNDC5 overexpression reduced serum BUN and SCr concentrations and alleviated pathological damage in the mouse renal tissues (P < 0.05) and exhibited a certain renal protective effect. FNDC5 overexpression can boost p-AMPK/AMPK, Nrf2, and HO-1 protein concentrations (P < 0.01).

Conclusion

FNDC5/irisin improves sepsis-induced acute renal injury by abating ferroptosis through the AMPK/Nrf2 signaling pathway.

The role of ACSL4 in stroke: mechanisms and potential therapeutic target

Stroke, as a neurological disorder with a poor overall prognosis, has long plagued the patients. Current stroke therapy lacks effective treatments. Ferroptosis has emerged as a prominent subject of discourse across various maladies in recent years. As an emerging therapeutic target, notwithstanding its initial identification in tumor cells associated with brain diseases, it has lately been recognized as a pivotal factor in the pathological progression of stroke. Acyl-CoA synthetase long-chain family member 4 (ACSL4) is a potential target and biomarker of catalytic unsaturated fatty acids mediating ferroptosis in stroke. Specifically, the upregulation of ACSL4 leads to heightened accumulation of lipid peroxidation products and reactive oxygen species (ROS), thereby exacerbating the progression of ferroptosis in neuronal cells. ACSL4 is present in various tissues and involved in multiple pathways of ferroptosis. At present, the pharmacological mechanisms of targeting ACSL4 to inhibit ferroptosis have been found in many drugs, but the molecular mechanisms of targeting ACSL4 are still in the exploratory stage. This paper introduces the physiopathological mechanism of ACSL4 and the current status of the research involved in ferroptosis crosstalk and epigenetics, and summarizes the application status of ACSL4 in modern pharmacology research, and discusses the potential application value of ACSL4 in the field of stroke.

The complex interplay between ferroptosis and atherosclerosis

Atherosclerosis, characterized by the accumulation of plaque within the arterial walls, is an intricate cardiovascular disease that often results in severe health issues. Recent studies have emphasized the importance of ferroptosis, a controlled type of cell death dependent on iron, as a critical factor in this disease state. Ferroptosis, distinguished by its reliance on iron and the accumulation of lipid hydroperoxides, offers a unique insight into the pathology of atherosclerotic lesions. This summary encapsulates the current knowledge of the intricate role ferroptosis plays in the onset and progression of atherosclerosis. It explores the molecular processes through which lipid peroxidation and iron metabolism contribute to the development of atheromatous plaques and evaluates the possibility of utilizing ferroptosis as a novel treatment approach for atherosclerosis. By illuminating the intricate relationship between ferroptosis-related processes and atherosclerosis, this review paves the way for future clinical applications and personalized medicine approaches aimed at alleviating the effects of atherosclerosis.

LPCAT3 exacerbates early brain injury and ferroptosis after subarachnoid hemorrhage in rats

AIMS

Lysophosphatidylcholine acyltransferase 3 (LPCAT3) is known to play a pivotal role in lipid metabolism, but its role in the early brain injury (EBI) following subarachnoid hemorrhage (SAH) remains unclear. This study provides insights into LPCAT3 expression alterations and functional implications in EBI following SAH.

METHODS

SAH models of adult male Sprague-Dawley (SD) rats were established by intravascular perforation. Lentivirus vectors were administered by intracerebroventricular injection (i.c.v.) to either induce LPCAT3 overexpression or knockdown 14 days before SAH induction. Western blot, immunofluorescence, Nissl staining, MDA detection, ROS detection, iron content detection, and short-term and long-term neurobehavioral tests were performed to investigate the effects of regulated-LPCAT3 after SAH.

RESULTS

LPCAT3 levels were found to be significantly elevated in SAH. Suppression of LPCAT3 expression via shRNA improved oxidative stress, reduced brain edema, alleviated behavioral and cognitive deficits following SAH and decreased neuronal death, while upregulating LPCAT3 expression showed opposing effects.

CONCLUSION

LPCAT3 is involved in SAH-induced EBI and associated with ferroptosis. Our findings provide a referential basis for potential therapeutic interventions aimed at alleviating EBI following SAH.

Effects of cognitive training and behavior modification on aggressive behavior and sleep quality in schizophrenia

Background

Schizophrenia (SCZ) is linked to a heightened risk of impulsive aggression and disturbances in sleep patterns. Cognitive and social cognitive impairments have been connected to aggression, with social cognitive deficits appearing to play a more immediate role. In this investigation, we conducted a retrospective analysis of the impact of cognitive training and sleep interventions on aggressive behavior and the quality of sleep among individuals with SCZ who were hospitalized.

Methods

This study divided 80 hospitalized patients into two groups according to medical advice, namely the normal group and the study group. The control group received routine drug treatment and education; The research group implemented cognitive training and sleep intervention based on the normal group. Collect basic clinical data, aggressive behavior indicators, and sleep quality indicators.

Results

There is no difference in the basic information statistics between the two groups. Both groups can reduce aggressive behavior and improve sleep quality. In the study group, there was a notable decrease in aggressive behavior compared to the control group. Furthermore, the sleep quality in the study group exhibited significant improvement when compared to the control group.

Conclusion

Cognitive training and sleep intervention have been proven to be effective nonpharmacological treatments, effectively reducing aggressive behavior and improving sleep quality.

Panax notoginseng Saponins Activate Nuclear Factor Erythroid 2-Related Factor 2 to Inhibit Ferroptosis and Attenuate Inflammatory Injury in Cerebral Ischemia-Reperfusion

Panax notoginseng saponins (PNS), the primary medicinal ingredient of Panax notoginseng, mitigates cerebral ischemia-reperfusion injury (CIRI) by inhibiting inflammation, regulating oxidative stress, promoting angiogenesis, and improving microcirculation. Moreover, PNS activates nuclear factor erythroid 2-related factor 2 (Nrf2), which is known to inhibit ferroptosis and reduce inflammation in the rat brain. However, the molecular regulatory roles of PNS in CIRI-induced ferroptosis remain unclear. In this study, we aimed to investigate the effects of PNS on ferroptosis and inflammation in CIRI. We induced ferroptosis in SH-SY5Y cells via erastin stimulation and oxygen glucose deprivation/re-oxygenation (OGD/R) in vitro. Furthermore, we determined the effect of PNS treatment in a rat model of middle cerebral artery occlusion/reperfusion and assessed the underlying mechanism. We also analyzed the changes in the expression of ferroptosis-related proteins and inflammatory factors in the established rat model. OGD/R led to an increase in the levels of ferroptosis markers in SH-SY5Y cells, which were reduced by PNS treatment. In the rat model, combined treatment with an Nrf2 agonist, Nrf2 inhibitor, and PNS-Nrf2 inhibitor confirmed that PNS promotes Nrf2 nuclear localization and reduces ferroptosis and inflammatory responses, thereby mitigating brain injury. Mechanistically, PNS treatment facilitated Nrf2 activation, thereby regulating the expression of iron overload and lipid peroxidation-related proteins and the activities of anti-oxidant enzymes. This cascade inhibited ferroptosis and mitigated CIRI. Altogether, these results suggest that the ferroptosis-mediated activation of Nrf2 by PNS reduces inflammation and is a promising therapeutic approach for CIRI.

A mechanism linking ferroptosis and ferritinophagy in melatonin-related improvement of diabetic brain injury

Ferroptosis and ferritinophagy play critical roles in various disease contexts. Herein, we observed that ferroptosis and ferritinophagy were induced both in the brains of mice with diabetes mellitus (DM) and neuronal cells after high glucose (HG) treatment, as evidenced by decreases in GPX4, SLC7A11, and ferritin levels, but increases in NCOA4 levels. Interestingly, melatonin administration ameliorated neuronal damage by inhibiting ferroptosis and ferritinophagy both in vivo and in vitro. At the molecular level, we found that not only the ferroptosis inducer p53 but also the ferritinophagy mediator NCOA4 was the potential target of miR-214-3p, which was downregulated by DM status or HG insult, but was increased after melatonin treatment. However, the inhibitory effects of melatonin on ferroptosis and ferritinophagy were blocked by miR-214-3p downregulation. These findings suggest that melatonin is a potential drug for improving diabetic brain damage by inhibiting p53-mediated ferroptosis and NCOA4-mediated ferritinophagy through regulating miR-214-3p in neurons.

Exploring the Role of Ferroptosis-Related Circular RNAs in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular event associated with high mortality and significant morbidity. Recent studies have highlighted the emerging role of ferroptosis, a novel form of regulated cell death, in the pathogenesis of SAH. Circular RNAs (circRNAs), have been found to play essential roles in various cellular processes, including gene regulation and disease pathogenesis. The expression profile of circRNAs in neural tissues, particularly in the brain, suggests their critical role in synaptic function and neurogenesis. Moreover, the interplay between circRNAs and ferroptosis-related pathways, such as iron metabolism and lipid peroxidation, is explored in the context of SAH. Understanding the functional roles of specific circRNAs in the context of SAH may provide potential therapeutic targets to attenuate ferroptosis-associated brain injury. Furthermore, the potential of circRNAs as diagnostic biomarkers for SAH severity, prognosis, and treatment response is discussed. Overall, this review highlights the significance of studying the intricate interplay between circRNAs and ferroptosis in the context of SAH. Unraveling the mechanisms by which circRNAs modulate ferroptotic cell death may pave the way for the development of novel therapeutic strategies and diagnostic approaches for SAH management, ultimately improving patient outcomes and quality of life.

Activating transcription factor 6 alleviates secondary brain injury by increasing cystathionine γ-lyase expression in a rat model of intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) comprises primary and secondary injuries, the latter of which induces increased inflammation and apoptosis and is more severe. Activating transcription factor 6 (ATF6) is a type-II transmembrane protein in the endoplasmic reticulum (ER). ATF6 target genes could improve ER homeostasis, which contributes to cryoprotection. Hence, we predict that ATF6 will have a protective effect on brain tissue after ICH.

METHOD

The ICH rat model was generated through autologous blood injection into the right basal ganglia, the expression of ATF6 after ICH was determined by WB and IF. The expression of ATF6 was effectively controlled by means of intervention, and a series of measures was used to detect cell death, neuroinflammation, brain edema, blood-brain barrier and other indicators after ICH. Finally, the effects on long-term neural function of rats were measured by behavioral means.

RESULT

ATF6 was significantly increased in the ICH-induced brain tissues. Further, ATF6 was found to modulate the expression of cystathionine γ-lyase (CTH) after ICH. Upregulation of ATF6 attenuated neuronal apoptosis and inflammation in ICH rats, along with mitigation of ICH-induced brain edema, blood-brain barrier deterioration, and cognitive behavior defects. Conversely, ATF6 genetic knockdown induced effects counter to those aforementioned.

CONCLUSIONS

This study thereby emphasizes the crucial role of ATF6 in secondary brain injury in response to ICH, indicating that ATF6 upregulation may potentially ameliorate ICH-induced secondary brain injury. Consequently, ATF6 could serve as a promising therapeutic target to alleviate clinical ICH-induced secondary brain injuries.

Sulfasalazine promotes ferroptosis through AKT-ERK1/2 and P53-SLC7A11 in rheumatoid arthritis

OBJECTIVE

Ferroptosis has been reported to play a role in rheumatoid arthritis (RA). Sulfasalazine, a common clinical treatment for ankylosing spondylitis, also exerts pathological influence on the progression of rheumatoid arthritis including the induced ferroptosis of fibroblast-like synoviocytes (FLSs), which result in the perturbated downstream signaling and the development of RA. The aim of this study was to investigate the underlying mechanism so as to provide novel insight for the treatment of RA.

METHODS

CCK-8 and Western blotting were used to assess the effect of sulfasalazine on FLSs. A collagen-induced arthritis mouse model was constructed by the injection of collagen and Freund's adjuvant, and then, mice were treated with sulfasalazine from day 21 after modeling. The synovium was extracted and ferroptosis was assessed by Western blotting and immunofluorescence staining.

RESULTS

The results revealed that sulfasalazine promotes ferroptosis. Compared with the control group, the expression levels of ferroptosis-related proteins such as glutathione peroxidase 4, ferritin heavy chain 1, and solute carrier family 7, member 11 (SLC7A11) were lower in the experimental group. Furthermore, deferoxamine inhibited ferroptosis induced by sulfasalazine. Sulfasalazine-promoted ferroptosis was related to a decrease in ERK1/2 and the increase of P53.

CONCLUSIONS

Sulfasalazine promoted ferroptosis of FLSs in rheumatoid arthritis, and the PI3K-AKT-ERK1/2 pathway and P53-SLC7A11 pathway play an important role in this process.

Ferroptosis in early brain injury after subarachnoid hemorrhage: review of literature

Spontaneous subarachnoid hemorrhage (SAH), mainly caused by ruptured intracranial aneurysms, is a serious acute cerebrovascular disease. Early brain injury (EBI) is all brain injury occurring within 72 h after SAH, mainly including increased intracranial pressure, decreased cerebral blood flow, disruption of the blood-brain barrier, brain edema, oxidative stress, and neuroinflammation. It activates cell death pathways, leading to neuronal and glial cell death, and is significantly associated with poor prognosis. Ferroptosis is characterized by iron-dependent accumulation of lipid peroxides and is involved in the process of neuron and glial cell death in early brain injury. This paper reviews the research progress of ferroptosis in early brain injury after subarachnoid hemorrhage and provides new ideas for future research.

Deferoxamine Mitigates Ferroptosis and Inflammation in Hippocampal Neurons After Subarachnoid Hemorrhage by Activating the Nrf2/TXNRD1 Axis

Ferroptosis is a distinct peroxidation-driven form of cell death tightly involved in subarachnoid hemorrhage (SAH). This study delved into the mechanism of deferoxamine (DFO, an iron chelator) in SAH-induced ferroptosis and inflammation. SAH mouse models were established by endovascular perforation method and injected intraperitoneally with DFO, or intraventricularly injected with the Nrf2 pathway inhibitor ML385 before SAH, followed by detection of neurological function, blood-brain barrier (BBB) permeability, and brain water content. Apoptotic level of hippocampal neurons, symbolic changes of ferroptosis, and levels of pro-inflammatory cytokines were assessed using TUNEL staining, Western blotting, colorimetry, and ELISA. The localization and expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) were detected. HT22 cells were exposed to Hemin as in vitro SAH models and treated with FIN56 to induce ferroptosis, followed by evaluation of the effects of DFO on FIN56-treated HT22 cells. The regulation of Nrf2 in thioredoxin reductase 1 (TXNRD1) was analyzed by co-immunoprecipitation and Western blotting. Moreover, HT22 cells were treated with DFO and ML385 to identify the role of DFO in the Nrf2/TXNRD1 axis. DFO extenuated brain injury, and ferroptosis and inflammation in hippocampal neurons of SAH mice. Nrf2 localized at the CA1 region of hippocampal neurons, and DFO stimulated nuclear translocation of Nrf2 protein in hippocampal neurons of SAH mice. Additionally, DFO inhibited ferroptosis and inflammatory responses in FIN56-induced HT22 cells. Nrf2 positively regulated TXNRD1 protein expression. Indeed, DFO alleviated FIN56-induced ferroptosis and inflammation via activation of the Nrf2/TXNRD1 axis. DFO alleviated neurological deficits, BBB disruption, brain edema, and brain injury in mice after SAH by inhibiting hippocampal neuron ferroptosis via the Nrf2/TXNRD1 axis. DFO ameliorates SAH-induced ferroptosis and inflammatory responses in hippocampal neurons by activating the Nrf2/TXNRD1 axis.

Ferroptosis as a Therapeutic Target in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a cerebrovascular disorder with significant mortality and morbidity. Neural injury in SAH is mediated through a variety of pathophysiological processes. Currently available treatments are either nonspecific in targeting the basic pathophysiological mechanisms that result in neural damage in SAH, or merely focus on vasospasm. Ferroptosis is a type of programmed iron dependent cell death, which has received attention due to its possible role in neural injury in SAH. Herein, we review how intracellular iron overload mediates the production of reactive free radicals and lipid peroxidation through a variety of biochemical pathways in SAH. This in turn results in induction of ferroptosis, as well as exacerbation of vasospasm. We also discuss several therapeutic agents that have been shown to inhibit ferroptosis through targeting different steps of the process. Such agents have proven effective in ameliorating vasospasm, neural damage, and neurobehavioral outcomes in animal models of SAH. Human studies to test the safety and efficacy of intrathecal or parenteral administration of the inhibitors of ferroptosis in improving outcomes of SAH patients are warranted. There are currently a few ongoing clinical trials pursuing this therapeutic concept, the results of which will be critical to determine the value of ferroptosis as a novel therapeutic target in SAH.

Astrocyte-derived hepcidin aggravates neuronal iron accumulation after subarachnoid hemorrhage by decreasing neuronal ferroportin1

Iron accumulation is one of the most essential pathological events after subarachnoid hemorrhage (SAH). Ferroportin1 (FPN1) is the only transmembrane protein responsible for exporting iron. Hepcidin, as the major regulator of FPN1, is responsible for its degradation. Our study investigated how the interaction between FPN1 and hepcidin contributes to iron accumulation after SAH. We found that iron accumulation aggravated after SAH, along with decreased FPN1 in neurons and increased hepcidin in astrocytes. After knocking down hepcidin in astrocytes, the neuronal FPN1 significantly elevated, thus attenuating iron accumulation. After SAH, p-Smad1/5 and Smad4 tended to translocate into the nucleus. Moreover, Smad4 combined more fragments of the promoter region of Hamp after OxyHb stimulation. By knocking down Smad1/5 or Smad4 in astrocytes, FPN1 level restored and iron overload attenuated, leading to alleviated neuronal cell death and improved neurological function. However, the protective role disappeared after recombinant hepcidin administration. Therefore, our study suggests that owing to the nuclear translocation of transcription factors p-Smad1/5 and Smad4, astrocyte-derived hepcidin increased significantly after SAH, leading to a decreased level of neuronal FPN1, aggravation of iron accumulation, and worse neurological outcome.

Menaquinone-4 attenuates ferroptosis by upregulating DHODH through activation of SIRT1 after subarachnoid hemorrhage

BACKGROUND

Menaquinone-4(MK-4), the isoform of vitamin K2 in the brain, exerts neuroprotective effects against a variety of central nervous system disorders. This study aimed to demonstrate the anti-ferroptosis effects of MK-4 in neurons after SAH.

METHODS

A subarachnoid hemorrhage (SAH) model was prepared by endovascular perforation in mice. In vitro hemoglobin stimulation of primary cortical neurons mimicked SAH. MK-4, Brequinar (BQR, DHODH inhibitor), and Selisistat (SEL, SIRT1 inhibitor) were administered, respectively. Subsequently, WB, immunofluorescence was used to determine protein expression and localization, and transmission electron microscopy was used to observe neuronal mitochondrial structure while other indicators of ferroptosis were measured.

RESULTS

MK-4 treatment significantly upregulated the protein levels of DHODH; decreased GSH, PTGS2, NOX1, ROS, and restored mitochondrial membrane potential. Meanwhile, MK-4 upregulated the expression of SIRT1 and promoted its entry into the nucleus. BQR or SEL partially abolished the protective effect of MK-4 on, neurologic function, and ferroptosis.

CONCLUSIONS

Taken together, our results suggest that MK-4 attenuates ferroptosis after SAH by upregulating DHODH through the activation of SIRT1.

Restoring System xc- activity by xCT overexpression inhibited neuronal ferroptosis and improved neurological deficits after experimental subarachnoid hemorrhage

BACKGROUND

Ferroptosis is an important therapeutic target to alleviate early brain injury (EBI) after subarachnoid hemorrhage (SAH), yet the mechanism of neuronal ferroptosis after SAH remains unclear. System xc- dysfunction is one of the key pathways to induce ferroptosis. System xc- activity is mainly regulated by the expression of xCT. This study was designed to investigate the effect of xCT expression and System xc- activity on ferroptosis and EBI in an experimental SAH model both in vitro and in vivo.

METHODS

SAH was induced in adult male Sprague-Dawley rats by injecting autologous blood into the prechiasmatic cistern. Primary neurons treated with oxyhemoglobin (10 µM) were used to mimic SAH in vitro. Plasmid transfection was used to induce xCT overexpression. Western blotting, immunofluorescence staining, measurement of cystine uptake, enzyme-linked immunosorbent assay, transmission electron microscopy, Nissl staining, and a series of neurobehavioral tests were conducted to explore the role of xCT and System xc- activity in ferroptosis and EBI after SAH.

RESULTS

We found that System xc- dysfunction induced ferroptosis and exacerbated EBI after SAH in rats. xCT deficiency after SAH resulted in System xc- dysfunction, weakened neuronal antioxidant capacity and activated neuronal ferroptosis. xCT overexpression improved neuronal antioxidant capacity and inhibited neuronal ferroptosis by restoring System xc- activity. Rats with xCT overexpression after SAH presented with attenuated brain edema and inflammation, increased neuronal survival, and ameliorated neurological deficits.

CONCLUSIONS

Our study revealed that restoring System xc- activity by xCT overexpression inhibited neuronal ferroptosis and EBI and improved neurological deficits after SAH.

Ferroptosis in Neurological Disease

Iron accumulation in the CNS occurs in many neurological disorders. It can contribute to neuropathology as iron is a redox-active metal that can generate free radicals. The reasons for the iron buildup in these conditions are varied and depend on which aspects of iron influx, efflux, or sequestration that help maintain iron homeostasis are dysregulated. Iron was shown recently to induce cell death and damage via lipid peroxidation under conditions in which there is deficient glutathione-dependent antioxidant defense. This form of cell death is called ferroptosis. Iron chelation has had limited success in the treatment of neurological disease. There is therefore much interest in ferroptosis as it potentially offers new drugs that could be more effective in reducing iron-mediated lipid peroxidation within the lipid-rich environment of the CNS. In this review, we focus on the molecular mechanisms that induce ferroptosis. We also address how iron enters and leaves the CNS, as well as the evidence for ferroptosis in several neurological disorders. Finally, we highlight biomarkers of ferroptosis and potential therapeutic strategies.

H3K9 trimethylation dictates neuronal ferroptosis through repressing Tfr1

Spontaneous intracerebral hemorrhage (ICH) is a devastating disease with high morbidity and mortality worldwide. We have previously shown that ferroptosis contributes to neuronal loss in ICH mice. The overload of iron and dysfunction of glutathione peroxidase 4 (GPx4) promote neuronal ferroptosis post-ICH. However, how epigenetic regulatory mechanisms affect the ferroptotic neurons in ICH remains unclear. In the current study, hemin was used to induce ferroptosis in N2A and SK-N-SH neuronal cells to mimic ICH. The results showed that hemin-induced ferroptosis was accompanied by an increment of global level of trimethylation in histone 3 lysine 9 (H3K9me3) and its methyltransferase Suv39h1. Transcriptional target analyses indicated that H3K9me3 was enriched at the promoter region and gene body of transferrin receptor gene 1 (Tfr1) and repressed its expression upon hemin stimulation. Inhibition of H3K9me3 with inhibitor or siRNA against Suv39h1 aggravated hemin- and RSL3-induced ferroptosis by upregulating Tfr1 expression. Furthermore, Suv39h1-H3K9me3 mediated repression of Tfr1 contributes to the progression of ICH in mice. These data suggest a protective role of H3K9me3 in ferroptosis post ICH. The knowledge gained from this study will improve the understanding of epigenetic regulation in neuronal ferroptosis and shed light on future clinical research after ICH.

Pharmacological Inhibition of Ferroptosis as a Therapeutic Target for Neurodegenerative Diseases and Strokes

Emerging evidence suggests that ferroptosis, a unique regulated cell death modality that is morphologically and mechanistically different from other forms of cell death, plays a vital role in the pathophysiological process of neurodegenerative diseases, and strokes. Accumulating evidence supports ferroptosis as a critical factor of neurodegenerative diseases and strokes, and pharmacological inhibition of ferroptosis as a therapeutic target for these diseases. In this review article, the core mechanisms of ferroptosis are overviewed and the roles of ferroptosis in neurodegenerative diseases and strokes are described. Finally, the emerging findings in treating neurodegenerative diseases and strokes through pharmacological inhibition of ferroptosis are described. This review demonstrates that pharmacological inhibition of ferroptosis by bioactive small-molecule compounds (ferroptosis inhibitors) could be effective for treatments of these diseases, and highlights a potential promising therapeutic avenue that could be used to prevent neurodegenerative diseases and strokes. This review article will shed light on developing novel therapeutic regimens by pharmacological inhibition of ferroptosis to slow down the progression of these diseases in the future.

Inhibition of ACSL4 Alleviates Parkinsonism Phenotypes by Reduction of Lipid Reactive Oxygen Species

Ferroptosis is a programmed cell death pathway that is recently linked to Parkinson's disease (PD), where the key genes and molecules involved are still yet to be defined. Acyl-CoA synthetase long-chain family member 4 (ACSL4) esterifies polyunsaturated fatty acids (PUFAs) which is essential to trigger ferroptosis, and is suggested as a key gene in the pathogenesis of several neurological diseases including ischemic stroke and multiple sclerosis. Here, we report that ACSL4 expression in the substantia nigra (SN) was increased in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated model of PD and in dopaminergic neurons in PD patients. Knockdown of ACSL4 in the SN protected against dopaminergic neuronal death and motor deficits in the MPTP mice, while inhibition of ACSL4 activity with Triacsin C similarly ameliorated the parkinsonism phenotypes. Similar effects of ACSL4 reduction were observed in cells treated with 1-methyl-4-phenylpyridinium (MPP+) and it specifically prevented the lipid ROS elevation without affecting the mitochondrial ROS changes. These data support ACSL4 as a therapeutic target associated with lipid peroxidation in PD.

The ACSL4 Network Regulates Cell Death and Autophagy in Diseases

Lipid metabolism, cell death, and autophagy are interconnected processes in cells. Dysregulation of lipid metabolism can lead to cell death, such as via ferroptosis and apoptosis, while lipids also play a crucial role in the regulation of autophagosome formation. An increased autophagic response not only promotes cell survival but also causes cell death depending on the context, especially when selectively degrading antioxidant proteins or organelles that promote ferroptosis. ACSL4 is an enzyme that catalyzes the formation of long-chain acyl-CoA molecules, which are important intermediates in the biosynthesis of various types of lipids. ACSL4 is found in many tissues and is particularly abundant in the brain, liver, and adipose tissue. Dysregulation of ACSL4 is linked to a variety of diseases, including cancer, neurodegenerative disorders, cardiovascular disease, acute kidney injury, and metabolic disorders (such as obesity and non-alcoholic fatty liver disease). In this review, we introduce the structure, function, and regulation of ACSL4; discuss its role in apoptosis, ferroptosis, and autophagy; summarize its pathological function; and explore the potential implications of targeting ACSL4 in the treatment of various diseases.

ACSL4-Mediated Ferroptosis and Its Potential Role in Central Nervous System Diseases and Injuries

As an iron-dependent regulated form of cell death, ferroptosis is characterized by iron-dependent lipid peroxidation and has been implicated in the occurrence and development of various diseases, including nervous system diseases and injuries. Ferroptosis has become a potential target for intervention in these diseases or injuries in relevant preclinical models. As a member of the Acyl-CoA synthetase long-chain family (ACSLs) that can convert saturated and unsaturated fatty acids, Acyl-CoA synthetase long-chain familymember4 (ACSL4) is involved in the regulation of arachidonic acid and eicosapentaenoic acid, thus leading to ferroptosis. The underlying molecular mechanisms of ACSL4-mediated ferroptosis will promote additional treatment strategies for these diseases or injury conditions. Our review article provides a current view of ACSL4-mediated ferroptosis, mainly including the structure and function of ACSL4, as well as the role of ACSL4 in ferroptosis. We also summarize the latest research progress of ACSL4-mediated ferroptosis in central nervous system injuries and diseases, further proving that ACSL4-medicated ferroptosis is an important target for intervention in these diseases or injuries.

Role of Protein Tyrosine Phosphatase 1B Inhibitor in Early Brain Injury of Subarachnoid Hemorrhage in Mice

Clinically, early brain injury (EBI), which refers to the acute injuries to the whole brain in the phase of the first 72 h following subarachnoid hemorrhage (SAH), is intensely investigated to improve neurological and psychological function. Additionally, it will be meaningful to explore new therapeutic approaches for EBI treatment to improve the prognosis of patients with SAH. To investigate the underlying neuroprotection mechanism in vitro, the Protein tyrosine phosphatase 1B inhibitor (PTP1B-IN-1) was put in primary neurons induced by OxyHb to observe neuroapoptosis, neuroinflammation, and ER stress. Then, one hundred forty male mice were subjected to Experiment two and Experiment three. The mice in the SAH24h + PTP1B-IN-1 group were given an intraperitoneal injection of 5 mg/kg PTP1B-IN-1 30 min before anesthesia. SAH grade, neurological score, brain water content, Western blot, PCR, and Transmission Electron Microscopy (TEM) were performed to observe the underlying neuroprotection mechanism in vivo. Overall, this study suggests that PTP1B-IN-1 could ameliorate neuroapoptosis, neuroinflammation, and ER stress in vitro and in vivo by regulating the IRS-2/AKT signaling pathway, suggesting that PTP1B-IN-1 may be a candidate drug for the treatment of early brain injury after SAH.

The mechanism of ferroptosis in early brain injury after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a cerebrovascular accident with an acute onset, severe disease characteristics, and poor prognosis. Within 72 hours after the occurrence of SAH, a sequence of pathological changes occur in the body including blood-brain barrier breakdown, cerebral edema, and reduced cerebrovascular flow that are defined as early brain injury (EBI), and it has been demonstrated that EBI exhibits an obvious correlation with poor prognosis. Ferroptosis is a novel programmed cell death mode. Ferroptosis is induced by the iron-dependent accumulation of lipid peroxides and reactive oxygen species (ROS). Ferroptosis involves abnormal iron metabolism, glutathione depletion, and lipid peroxidation. Recent study revealed that ferroptosis is involved in EBI and is significantly correlated with poor prognosis. With the gradual realization of the importance of ferroptosis, an increasing number of studies have been conducted to examine this process. This review summarizes the latest work in this field and tracks current research progress. We focused on iron metabolism, lipid metabolism, reduction systems centered on the GSH/GPX4 system, other newly discovered GSH/GPX4-independent antioxidant systems, and their related targets in the context of early brain injury. Additionally, we examined certain ferroptosis regulatory mechanisms that have been studied in other fields but not in SAH. A link between death and oxidative stress has been described. Additionally, we highlight the future research direction of ferroptosis in EBI of SAH, and this provides new ideas for follow-up research.

Early Brain Injury After Subarachnoid Hemorrhage: Incidence and Mechanisms

Aneurysmal subarachnoid hemorrhage is a devastating condition causing significant morbidity and mortality. While outcomes from subarachnoid hemorrhage have improved in recent years, there continues to be significant interest in identifying therapeutic targets for this disease. In particular, there has been a shift in emphasis toward secondary brain injury that develops in the first 72 hours after subarachnoid hemorrhage. This time period of interest is referred to as the early brain injury period and comprises processes including microcirculatory dysfunction, blood-brain-barrier breakdown, neuroinflammation, cerebral edema, oxidative cascades, and neuronal death. Advances in our understanding of the mechanisms defining the early brain injury period have been accompanied by improved imaging and nonimaging biomarkers for identifying early brain injury, leading to the recognition of an elevated clinical incidence of early brain injury compared with prior estimates. With the frequency, impact, and mechanisms of early brain injury better defined, there is a need to review the literature in this area to guide preclinical and clinical study.

HIV-1 Tat-mediated microglial ferroptosis involves the miR-204–ACSL4 signaling axis

This study was focused on exploring the role of the HIV-1 Tat protein in mediating microglial ferroptosis. Exposure of mouse primary microglial cells (mPMs) to HIV-1 Tat protein resulted in induction of ferroptosis, which was characterized by increased expression of Acyl-CoA synthetase long-chain family member 4 (ACSL4), in turn, leading to increased generation of oxidized phosphatidylethanolamine, elevated levels of lipid peroxidation, upregulated labile iron pool (LIP) and ferritin heavy chain-1 (FTH1), decreased glutathione peroxidase-4 and mitochondrial outer membrane rupture. Also, inhibition of ferroptosis by ferrostatin-1 (Fer-1) or deferoxamine (DFO) treatment suppressed ferroptosis-related changes in mPMs. Similarly, the knockdown of ACSL4 by gene silencing also inhibited ferroptosis induced by HIV-1 Tat. Furthermore, increased lipid peroxidation resulted in increased release of proinflammatory cytokines, such as TNFα, IL6, and IL1β and microglial activation. Pretreatment of mPMs with Fer-1 or DFO further blocked HIV-1 Tat-mediated microglial activation in vitro and reduced the expression and release of proinflammatory cytokines. We identified miR-204 as an upstream modulator of ACSL4, which was downregulated in mPMs exposed to HIV-1 Tat. Transient transfection of mPMs with miR-204 mimics reduced the expression of ACSL4 while inhibiting HIV-1 Tat-mediated ferroptosis and the release of proinflammatory cytokines. These in vitro findings were further validated in HIV-1 transgenic rats as well as HIV + ve human brain samples. Overall, this study underscores a novel mechanism(s) underlying HIV-1 Tat-mediated ferroptosis and microglial activation involving miR-204-ACSL4 signaling.

Circadian Rhythm Regulator REV-ERBα Attenuates Neuroapoptosis in Early Brain Injury After Experimental Subarachnoid Hemorrhage in Rats

Subarachnoid hemorrhage (SAH) is associated with circadian rhythm abnormalities, in which REV-ERBα plays a major regulatory role. Our ambition was to investigate the capacity of REV-ERBα to inhibit neuronal neuroapoptosis induced by early brain injury (EBI) after SAH. The endovascular perforation model was used to produce experimental SAH in Sprague-Dawley rats. Specific small-interfering RNA was used to downregulate the expression REV-ERBα while SR9009 was used to upregulate the expression before assessments. Short- and long-term neurobehavior assessments, immunofluorescence staining, TUNEL staining, Nissl staining, brain water content, and Western blot were performed. The expression level of endogenous REVERBα tended to increase and then decrease after SAH and peaked at 48 h. REV-ERBα upregulation diminished neuronal apoptosis and enhanced neurological function deficits. Meanwhile, REV-ERBα downregulation aggravated the damage. Furthermore, the levels of downstream proteins of REV-ERBα (i.e., brain and muscle ARNT-like 1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK)) changed accordingly with REV-ERBα regulation. REV-ERBα may attenuate neuronal apoptosis in EBI after SAH through the BMAL1/CLOCK pathway.

Intermittent fasting ameliorates neuronal ferroptosis and cognitive impairment in mice after traumatic brain injury

Ferroptosis, a newly characterized form of programmed cell death that results from lipid peroxidation and mitochondrial dysfunction, has been demonstrated to be involved in the pathogenesis of traumatic brain injury (TBI). Scientific evidence has shown that intermittent fasting (IF) reduces both the lipid peroxidation and the mitochondrial dysfunction, raising the question of whether IF affects the ferroptosis induced by TBI. Here, based on an established TBI animal model, we examine the effects of IF on the activation of ferroptosis pathway as well as related outcomes. We uncovered that a 1-mo IF elevated the protective Gpx4 and Hspb1 expression, and partly abolished the increase of Nfe2l2, Slc7a11, Alox8, Steap3, and Nox2 in the cortex, which were induced by TBI. Furthermore, the characteristic cellular damage induced by ferroptosis was alleviated by IF, as revealed by Perls' Prussian blue staining, Nissl staining, and transmission electron microscope examination. Consistently, we examined the outcomes of mice subjected to TBI and found an improved cognitive function of the IF mice. In sum, our study demonstrated, to our knowledge for the first time, that a 1-mo IF regimen partly ameliorates ferroptosis in the cortex of mice subjected to TBI, which potentially contributes to a lessening of cognitive impairment.

Elucidating the progress and impact of ferroptosis in hemorrhagic stroke

Hemorrhagic stroke is a devastating cerebrovascular disease with high morbidity and mortality, for which effective therapies are currently unavailable. Based on different bleeding sites, hemorrhagic stroke can be generally divided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), whose pathogenesis share some similarity. Ferroptosis is a recently defined programmed cell deaths (PCDs), which is a critical supplement to the hypothesis on the mechanism of nervous system injury after hemorrhagic stroke. Ferroptosis is characterized by distinctive morphological changes of mitochondria and iron-dependent accumulation of lipid peroxides. Moreover, scientists have successfully demonstrated the involvement of ferroptosis in animal models of ICH and SAH, indicating that ferroptosis is a promising target for hemorrhagic stroke therapy. However, the studies on ferroptosis still faces a serious of technical and theoretical challenges. This review systematically elaborates the role of ferroptosis in the pathogenesis of hemorrhagic stroke and puts forward some opinions on the dilemma of ferroptosis research.

Molecular mechanisms of neuronal death in brain injury after subarachnoid hemorrhage

Subarachnoid haemorrhage (SAH) is a common cerebrovascular disease with high disability and mortality rates worldwide. The pathophysiological mechanisms involved in an aneurysm rupture in SAH are complex and can be divided into early brain injury and delayed brain injury. The initial mechanical insult results in brain tissue and vascular disruption with hemorrhages and neuronal necrosis. Following this, the secondary injury results in diffused cerebral damage in the peri-core area. However, the molecular mechanisms of neuronal death following an aneurysmal SAH are complex and currently unclear. Furthermore, multiple cell death pathways are stimulated during the pathogenesis of brain damage. Notably, particular attention should be devoted to necrosis, apoptosis, autophagy, necroptosis, pyroptosis and ferroptosis. Thus, this review discussed the mechanism of neuronal death and its influence on brain injury after SAH.

An update on the therapeutic implications of long-chain acyl-coenzyme A synthetases in nervous system diseases

Long-chain acyl-coenzyme A synthetases (ACSLs) are a family of CoA synthetases that activate fatty acid (FA) with chain lengths of 12-20 carbon atoms by forming the acyl-AMP derivative in an isozyme-specific manner. This family mainly includes five members (ACSL1, ACSL3, ACSL4, ACSL5, and ACSL6), which are thought to have specific and different functions in FA metabolism and oxidative stress of mammals. Accumulating evidence shows that the dysfunction of ACSLs is likely to affect cell proliferation and lead to metabolic diseases in multiple organs and systems through different signaling pathways and molecular mechanisms. Hence, a central theme of this review is to emphasize the therapeutic implications of ACSLs in nervous system disorders.

Ferroptosis of Endothelial Cells in Vascular Diseases

Endothelial cells (ECs) line the inner surface of blood vessels and play a substantial role in vascular biology. Endothelial dysfunction (ED) is strongly correlated with the initiation and progression of many vascular diseases. Regulated cell death, such as ferroptosis, is one of the multiple mechanisms that lead to ED. Ferroptosis is an iron-dependent programmed cell death associated with various vascular diseases, such as cardiovascular, cerebrovascular, and pulmonary vascular diseases. This review summarized ferroptosis of ECs in vascular diseases and discussed potential therapeutic strategies for treating ferroptosis of ECs. In addition to lipid peroxidation inhibitors and iron chelators, a growing body of evidence showed that clinical drugs, natural products, and intervention of noncoding RNAs may also inhibit ferroptosis of ECs.

Ferroptosis contributes to hypoxic-ischemic brain injury in neonatal rats: Role of the SIRT1/Nrf2/GPx4 signaling pathway

AIMS

Hypoxic-ischemic brain injury (HIBI) often results in cognitive impairments. Herein, we investigated the roles of ferroptosis in HIBI and the underlying signaling pathways.

METHODS

Ferrostatin-1 (Fer-1) or resveratrol (Res) treatments were administered intracerebroventricularly 30 min before HIBI in 7-day-old rats. Glutathione peroxidase 4 (GPx4) expression, malondialdehyde (MDA) concentration, iron content, mitochondrial morphology, and the expression of silent information regulator factor 2-related enzyme 1 (SIRT1) and nuclear factor erythroid-2-related factor 2 (Nrf2) were measured after HIBI. Additionally, the weight ratio of left/right hemisphere, brain morphology, Nissl staining, and the Morris water maze test were conducted to estimate brain damage.

RESULTS

At 24-h post-HIBI, GPx4 expression was decreased, and MDA concentration and iron content were increased in the hippocampus. HIBI led to mitochondrial atrophy, brain atrophy/damage, and resultant learning and memory impairments, which were alleviated by Fer-1-mediated inhibition of ferroptosis. Furthermore, Res-mediated SIRT1 upregulation increased Nrf2 and GPx4 expression, thereby attenuating ferroptosis, reducing brain atrophy/damage, and improving learning and memory abilities.

CONCLUSION

The results demonstrated that during HIBI, ferroptosis occurs via the SIRT1/Nrf2/GPx4 signaling pathway, suggesting it as a potential therapeutic target for inhibiting ferroptosis and ameliorating HIBI-induced cognitive impairments.

Enhanced natural killer cell anti-tumor activity with nanoparticles mediated ferroptosis and potential therapeutic application in prostate cancer

Ferroptosis provides an opportunity to overcome the cancer cell therapeutic resistance and modulate the immune system. Here an interaction between ferroptosis of cancer cells and natural killer (NK) cells was investigated with a clinical grade iron oxide nanoparticle (ferumoxytol) for potential synergistic anti-cancer effect of ferroptosis and NK cell therapy in prostate cancer. When ferumoxytol mediated ferroptosis of cancer cells was combined with NK cells, the NK cells' cytotoxic function was increased. Observed ferroptosis mediated NK cell activation was also confirmed with IFN-γ secretion and lytic degranulation. Upregulation of ULBPs, which is one of the ligands for NK cell activating receptor NKG2D, was observed in the co-treatment of ferumoxytol mediated ferroptosis and NK cells. Additionally, HMGB1 and PD-L1 expression of cancer cells were observed in the treatment of ferroptosis + NK cells. Finally, in vivo therapeutic efficacy of ferumoxytol mediated ferroptosis and NK cell therapy was observed with significant tumor volume regression in a prostate cancer mice model. These results suggest that the NK cells' function can be enhanced with ferumoxytol mediated ferroptosis.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.

Astragaloside IV attenuates ferroptosis after subarachnoid hemorrhage via Nrf2/HO-1 signaling pathway

Subarachnoid hemorrhage (SAH) is a severe type of stroke featuring exceptionally high rate of morbidity and mortality due to the lack of effective management. Ferroptosis can be defined as a novel iron-dependent programmed cell death in contrast to classical apoptosis and necrosis. Astragaloside IV (AS-IV) is an active ingredient extracted from Astragalus membranaceus with established therapeutic effect on CNS diseases. However, the exact role of ferroptosis in Astragaloside IV-mediated neuroprotection after SAH is yet to be demonstrated. In the present study, the SAH model of SD male rats with endovascular perforation was used to gauge the neuroprotective effect of AS-IV on SAH-induced early brain injury (EBI) and to clarify the potential molecular mechanism. We found that the induction of SAH reduced the levels of SLC7A11 and glutathione peroxidase 4 (GPX4) in the brain, exacerbated iron accumulation, enhanced lipid reactive oxygen species (ROS) level, and stimulated neuronal ferroptosis. However, the administration of AS-IV and the ferroptosis inhibitor Ferrostatin-1 (Fer-1) enhanced the antioxidant capacity after SAH and suppressed the accumulation of lipid peroxides. Meanwhile, AS-IV triggered Nrf2/HO-1 signaling pathway and alleviated ferroptosis due to the induction of SAH. The Nrf2 inhibitor ML385 blocked the beneficial effects of neuroprotection. These results consistently suggest that ferroptosis is profoundly implicated in facilitating EBI in SAH, and that AS-IV thwarts the process of ferroptosis in SAH by activating Nrf2/HO-1 pathway.

The protective mechanism of protein kinase R to inhibit neuronal ferroptosis in cerebral injury from subarachnoid hemorrhage

PURPOSE

To investigate the role and mechanism of protein kinase R (PKR) in subarachnoid hemorrhage (SAH)-mediated ferroptosis.

METHODS

A rat SAH model was constructed and treated with PKR inhibitor C16 to observe SAH and neurological impairment in rats and to detect malonaldehyde (MDA), iron ions content, ferritin heavy polypeptide 1 (FTH1) and glutathione peroxidase 4 (GPX4), and other related ferroptosis indicators in brain tissue. RNA sequencing analysis was used to investigate the mechanism of PKR, affecting the ferroptosis network of SAH.

RESULTS

SAH caused severe fundic hemorrhage, neurological impairment, MDA and iron ion accumulation, and significant decrease in GPX4 and FTH1 levels in rats. C16 treatment significantly improved the above signs caused by SAH. By RNA-seq analysis, brain tissue of SAH-treated rats with SAH and C16 differentially expressed mRNA target genes enriched in stress response and organic developmental signaling pathways.

CONCLUSION

Inhibition of PKR may improve cerebral injury after SAH by inhibiting ferroptosis, and RNA sequencing staged its mechanism of action may be related to the stress response.

S100A8 regulates autophagy-dependent ferroptosis in microglia after experimental subarachnoid hemorrhage

Targeting microglial activation has been shown to ameliorate early brain injury (EBI) after subarachnoid hemorrhage (SAH). Ferroptosis is a new form of programmed cell death after SAH, but these molecular features were not recognized as evidence of microglial function so far. In this study, we constructed microglial S100A8-specific knockdown and established the SAH model in vivo and in vitro. Multi-technology strategies, including high throughput sequencing, adeno-associated virus gene gene-editing and several molecular biotechnologies to validate the effects of S100A8 on microglial autophagy and ferroptosis after SAH. Our results revealed that the expression of S100A8 was significantly increased in brain tissue after SAH. Targeted microglial S100A8 inhibition improved neural function and neuronal apoptosis in mice after SAH. Further mechanism exploration found that favourable effects of S100A8 depletion in EBI may be through the inhibition of microglia autophagy-dependent ferroptosis. In conclusion, S100A8 may be a potential intervention target for microglial ferroptosis in EBI after SAH.

New Mechanisms and Targets of Subarachnoid Hemorrhage: A Focus on Mitochondria

Spontaneous subarachnoid hemorrhage (SAH) accounts for 5-10% of all strokes and is a subtype of hemorrhagic stroke that places a heavy burden on health care. Despite great progress in surgical clipping and endovascular treatment for ruptured aneurysms, cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI) threaten the long-term outcomes of patients with SAH. Moreover, there are limited drugs available to reduce the risk of DCI and adverse outcomes in SAH patients. New insight suggests that early brain injury (EBI), which occurs within 72 h after the onset of SAH, may lay the foundation for further DCI development and poor outcomes. The mechanisms of EBI mainly include excitotoxicity, oxidative stress, neuroinflammation, blood-brain barrier (BBB) destruction, and cellular death. Mitochondria are a double-membrane organelle, and they play an important role in energy production, cell growth, differentiation, apoptosis, and survival. Mitochondrial dysfunction, which can lead to mitochondrial membrane potential (Δψm) collapse, overproduction of reactive oxygen species (ROS), release of apoptogenic proteins, disorders of mitochondrial dynamics, and activation of mitochondria-related inflammation, is considered a novel mechanism of EBI related to DCI as well as post-SAH outcomes. In addition, mitophagy is activated after SAH. In this review, we discuss the latest perspectives on the role of mitochondria in EBI and DCI after SAH. We emphasize the potential of mitochondria as therapeutic targets and summarize the promising therapeutic strategies targeting mitochondria for SAH.

ACSL4 is overexpressed in psoriasis and enhances inflammatory responses by activating ferroptosis

More and more studies have shown that ferroptosis is closely related to the progression of various diseases, but the significance of ferroptosis in psoriasis is still rarely explored. The detection of plasma and psoriatic lesions found that the contents of MDA and ROS were significantly increased, while the contents of SOD and GSH were significantly decreased, and the trend of increase or decrease in patients with progressive psoriasis was more obvious. The expression of ACSL4, a key regulator of ferroptosis, was significantly increased in psoriatic lesions and further up-regulated in patients with progressive psoriasis. ACSL4 expression was positively correlated with PASI score and the expression levels of inflammatory cytokines (TNF-α, IL-6, IL-8 and IL-17a), and linear regression analysis showed that high expression of ACSL4 in psoriatic lesions was associated with higher PASI score. Both ferroptosis inducer Erastin and IFN-γ/TNF-α significantly induced ferroptosis, inhibited keratinocyte viability, promoted the accumulation of MDA, ROS and Fe²⁺, and enhanced ACSL4, TNF-α, IL-6 and IL-8 expression. When ferroptosis inhibitor Ferrostatin-1 was added to inhibit ferroptosis, the up-regulation trends of MDA, ROS, Fe²⁺, ACSL4, TNF-α, IL-6 and IL-8 were significantly inhibited, and inhibition of ACSL4 expression also had a similar effect. Apoptosis inhibitor Z-VAD-FMK could also attenuate the pro-inflammatory effect of IFN-γ/TNF-α, and Fer-1 plus Z-VAD-FMK further inhibited the expression of inflammatory cytokines. Thus, ferroptosis is significantly activated during the progression of psoriasis and promotes inflammatory responses by upregulating ACSL4 expression. This discovery will provide new targets for clinical detection, prevention and treatment of psoriasis.

Activation of SIRT1 Alleviates Ferroptosis in the Early Brain Injury after Subarachnoid Hemorrhage

Ferroptosis is a regulated cell death that characterizes the lethal lipid peroxidation and iron overload, which may contribute to early brain injury (EBI) pathogenesis after subarachnoid hemorrhage (SAH). Although Sirtuin 1 (SIRT1), a class III histone deacetylase, has been proved to have endogenous neuroprotective effects on the EBI following SAH, the role of SIRT1 in ferroptosis has not been studied. Hence, we designed the current study to determine the role of ferroptosis in the EBI and explore the correlation between SIRT1 and ferroptosis after SAH. The pathways of ferroptosis were examined after experimental SAH in vivo (prechiasmatic cistern injection mouse model) and in HT-22 cells stimulated by oxyhemoglobin (oxyHb) in vitro. Then, ferrostatin-1 (Fer-1) was used further to determine the role of ferroptosis in EBI. Finally, we explored the correlation between SIRT1 and ferroptosis via regulating the expression of SIRT1 by resveratrol (RSV) and selisistat (SEL). Our results showed that ferroptosis was involved in the pathogenesis of EBI after SAH through multiple pathways, including acyl-CoA synthetase long-chain family member 4 (ACSL4) activation, iron metabolism disturbance, and the downregulation of glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1). Inhibition of ferroptosis by Fer-1 significantly alleviated oxidative stress-mediated brain injury. SIRT1 activation could suppress SAH-induced ferroptosis by upregulating the expression of GPX4 and FSP1. Therefore, ferroptosis could be a potential therapeutic target for SAH, and SIRT1 activation is a promising method to inhibit ferroptosis.

Growth Differentiation Factor 15 Regulates Oxidative Stress-Dependent Ferroptosis Post Spinal Cord Injury by Stabilizing the p62-Keap1-Nrf2 Signaling Pathway

Background

Spinal cord injury (SCI) is a severe traumatic disorder of the central nervous system (CNS) that causes irreversible damage to the nervous tissue. The consequent hemorrhage contributed by trauma induces neuronal ferroptosis post SCI, which is an important death mode to mediate neuronal loss. Growth differentiation factor 15 (GDF15) is a cytokine that regulates cell proliferation, differentiation, and death. However, the specific role of GDF15 in neuronal ferroptosis post SCI remains unknown.

Materials and Methods

Neuronal ferroptosis in vitro was measured by detection of lipid peroxidation, glutathione, iron content, and reactive oxidative stress. In vivo, western blotting and immunofluorescence (IF) staining was utilized to measure ferroptosis post SCI. IF staining, TUNEL staining, hematoxylin-eosin staining, and Nissl staining were used to measure neurological damage. Finally, locomotor function recovery was analyzed using the Basso Mouse Scale and Louisville Swim Scale.

Results

GDF15 was significantly increased in neuronal ferroptosis and silencing GDF15 aggravated ferroptosis both in vitro and in vivo. Besides, GDF15-mediated inhibition of neuronal ferroptosis is through p62-dependent Keap1-Nrf2 pathway. In SCI mice, knockdown of GDF15 significantly exacerbated neuronal death, interfered with axon regeneration and remyelination, aggravated ferroptosis-mediated neuroinflammation, and restrained locomotor recovery.

Conclusion

GDF15 effectively alleviated neuronal ferroptosis post SCI via the p62-Keap1-Nrf2 signaling pathway and promoted locomotor recovery of SCI mice, which is suggested as a potential target on SCI pathogenesis and treatment.

Aquaporin 4 Depolarization-Enhanced Transferrin Infiltration Leads to Neuronal Ferroptosis after Subarachnoid Hemorrhage in Mice

The infiltration of blood components into the brain parenchyma through the lymphoid system is an important cause of subarachnoid hemorrhage injury. AQP4, a water channel protein located at the astrocyte foot, has been reported to regulate blood-brain barrier integrity, and its polarization is disrupted after SAH. Neuronal ferroptosis is involved in subarachnoid hemorrhage- (SAH-) induced brain injury, but the inducing factors are not completely clear. Transferrin is one of the inducing factors of ferroptosis. This study is aimed at researching the role and mechanism of AQP4 in brain injury after subarachnoid hemorrhage in mice. An experimental mouse SAH model was established by endovascular perforation. An AAV vector encoding AQP4 with a GFAP-specific promoter was administered to mice to achieve specific overexpression of AQP4 in astrocytes. PI staining, Fer-1 intervention, and transmission electron microscopy were used to detect neuronal ferroptosis, and dextran (40 kD) leakage was used to detect BBB integrity. Western blot analysis of perfused brain tissue protein samples was used to detect transferrin infiltration. First, neuronal ferroptosis 24 h after SAH was observed by PI staining and Fer-1 intervention. Second, a significant increase in transferrin infiltration was found in the brain parenchyma 24 h after SAH modeling, while transferrin content was positively correlated with neuronal ferroptosis. Then, we observed that AQP4 overexpression effectively improved AQP depolarization and BBB injury induced by SAH and significantly reduced transferrin infiltration and neuronal ferroptosis after SAH. Finally, we found that AQP4 overexpression could effectively improve the neurobehavioral ability of SAH mice, and the neurobehavioral ability was negatively correlated with transferrin brain content. Taken together, these data indicate that overexpression of AQP4 in the mouse brain can effectively improve post-SAH neuronal ferroptosis and brain injury, at least partly by inhibiting transferrin infiltration into the brain parenchyma in the glymphatic system.