GPX4 deficiency-dependent phospholipid peroxidation drives motor deficits of ALS

A prospective therapeutic strategy: GPX4-targeted ferroptosis mediators

As a crucial regulator of oxidative homeostasis, seleno-protein glutathione peroxidase 4 (GPX4) represents the primary defense system against ferroptosis, making it a promising target with important clinical application prospects. From the discovery of covalent and allosteric sites in GPX4, substantial advancements in GPX4-targeted small molecules have been made through diverse discovery and design strategies in recent years. Moreover, as an emerging hotspot in drug development, seleno-organic compounds can functionally mimic GPX4 to reduce hydroperoxides. To facilitate the further development of selective ferroptosis mediators as potential pharmaceutical agents, this review comprehensively covers all GPX4-targeted small molecules, including inhibitors, degraders, and activators. In addition, seleno-organic compounds as GPX mimics are also included. We also provide perspectives regarding challenges and future research directions in this field.

Triple-helix β-glucan-based self-assemblies, synthesis, characterization and anticarcinogenic effect

Triple negative breast cancer (TNBC) seriously endangers women's life and health due to its high invasion and mortality. Reactive oxygen species (ROS) mediated tumor cells apoptosis is considered an effective anticancer approach. Herein, we designed a natural active triple helix β-Glucan (BFP) wrapped single walled carbon nanotubes (SWNTs)-loaded doxorubicin (DOX) self-assembly (BSD) via generating excess ROS to induce oxidative stress damage for TNBC therapy. BSD could directly consume glutathione (GSH) to promote ROS. In vitro results demonstrated that BSD exhibited obvious antitumor effects to breast cancer cells by promoting apoptosis. Un-targeted metabolomics under molecular level identified the specific metabolic targets and unveiled that BSD markedly disturbed multiple metabolic pathways, including purine metabolism, pentose phosphate pathway, glutathione metabolism pathways, amino sugar and nucleotide sugar metabolism and energy metabolism, led to the inhibition of DNA and RNA synthesis, the generation of ROS, the exacerbation of DNA damage, the disruption of cell membrane integrity and the decrease of ATP. In vitro and in vivo oxidative stress assays further verified that BSD significantly promoted intracellular oxidative stress and resulted in cell damage. This study provides theoretical basis for the development and screening of new drugs based on ROS therapy for TNBC.

Matrine protects against experimental autoimmune encephalomyelitis through modulating microglial ferroptosis

Multiple sclerosis (MS) is an inflammatory demyelination neurodegenerative disease of the central nervous system (CNS). Ferroptosis has been implicated in a range of brain disorders, and iron-loaded microglia are frequently found in affected brain regions. However, the molecular mechanisms linking ferroptosis with MS have not been well-defined. The present study seeks to bridge this gap and investigate the impact of matrine (MAT), a herbal medicine with immunomodulatory capacities, on the regulation of oxidative stress and ferroptosis in the CNS of mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. CNS of EAE mice contained elevated levels of ferroptosis-related molecules, e.g., MDA, LPCAT3 and PTGS2, but decreased expression of antioxidant molecules, including GSH and SOD, GPX4 and SLC7A11. This pathogenic process was reversed by MAT treatment, together with significant reduction of disease severity and CNS inflammatory demyelination. Furthermore, the expression of PTGS2 and LOX was largely increased in microglia of EAE mice, accompanied with increased production of IL-6 and TNF-α, indicating a proinflammatory phenotype of microglia that undergo oxidative stress/ferroptosis, and their expression was significantly reduced after MAT treatment. Together, our results indicate that ferroptosis/inflammation plays an important role in the pathogenesis of CNS autoimmunity, and inhibiting ferroptosis-induced microglial activation/inflammation could be a novel mechanism underlying the therapeutic effects of MAT on CNS inflammatory demyelination in EAE.

Ferroptosis and Its Potential Role in the Physiopathology of Skeletal Muscle Atrophy

Skeletal muscle atrophy is a major health concern, severely affecting the patient's mobility and life quality. In the pathological process of skeletal muscle atrophy, with the progressive decline in muscle quality, strength, and function, the incidence of falling, fracture, and death is greatly increased. Unfortunately, there are no effective treatments for this devastating disease. Thus, it is imperative to investigate the exact pathological molecular mechanisms underlying the development of skeletal muscle atrophy and to identify new therapeutic targets. Decreased muscle mass, strength, and muscle fiber cross-sectional area are typical pathological features and manifestations of skeletal muscle atrophy. Ferroptosis, an emerging type of programmed cell death, is characterized by iron-dependent oxidative damage, lipid peroxidation, and reactive oxygen species accumulation. Notably, the understanding of its role in skeletal muscle atrophy is emerging. Ferroptosis has been found to play an important role in the intricate interplay between the pathological mechanisms of skeletal muscle atrophy and its progression caused by multiple factors. This provides new opportunities and challenges in the treatment of skeletal muscle atrophy. Therefore, we systematically elucidated the ferroptosis mechanism and its progress in skeletal muscle atrophy, aiming to provide a comprehensive insight into the intricate relationship between ferroptosis and skeletal muscle atrophy from the perspectives of iron metabolism and lipid peroxidation and to provide new insights for targeting the pathways related to ferroptosis and the treatment of skeletal muscle atrophy.

Amyloid fibril structures and ferroptosis activation induced by ALS-causing SOD1 mutations

Over 200 genetic mutations in copper-zinc superoxide dismutase (SOD1) have been linked to amyotrophic lateral sclerosis (ALS). Among these, two ALS-causing mutants, histidine-46→arginine (H46R) and glycine-85→arginine (G85R), exhibit a decreased capacity to bind metal ions. Here, we report two cryo-electron microscopy structures of amyloid fibrils formed by H46R and G85R. These mutations lead to the formation of amyloid fibrils with unique structures distinct from those of the native fibril. The core of these fibrils features a serpentine arrangement with seven or eight β strands, secured by a hydrophobic cavity and a salt bridge between arginine-85 and aspartic acid-101 in the G85R fibril. We demonstrate that these mutant fibrils are notably more toxic and capable of promoting the aggregation of wild-type SOD1 more effectively, causing mitochondrial impairment and activating ferroptosis in cell cultures, compared to wild-type SOD1 fibrils. Our study provides insights into the structural mechanisms by which SOD1 mutants aggregate and induce cytotoxicity in ALS.

Hypoxia-inducible factor-1 as targets for neuroprotection : from ferroptosis to Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disease characterized by motor paralysis, tremor,and cognitive impairment. Risk factors such as brain hypoxia caused by aging and abnormal expression of HIF-1α areconsidered to be key to the development of PD, including α-synuclein accumulation and ferroptosis. However, therelationship between HIF-1α signaling and ferroptosis in PD has not been elucidated. The stable expression of HIF-1αinhibits the pathological development of PD. Aging aggravates PD pathology by promoting α-synuclein accumulationand oxidative stress.

METHODS

The literature on lipid peroxidation, oxidative stress, iron metabolism and other key factors in Parkinson'sdisease in recent years was reviewed through a variety of literature search channels, such as PubMed and Elsevier.

RESULTS

HIF-1α mediated ferroptosis through oxidative stress and GPX4-GSH system. HIF-1α mediates ferroptosisthrough Keap1-Nrf2-ARE, Grx3 and Grx4. HIF-1α mediates ferroptosis through iron metabolism.

CONCLUSION

This article reviews the oxygen-dependent regulatory mechanism of HIF-1α and its role in cerebralhypoxia homeostasis. Studies in the past decade have shown that Hif-1α mediated ferroptosis is important in PD.HIF-1α has a dual role, depending on the degree of cellular hypoxia and the environment. The equilibrium complexityneeds to be explained, and the role of ferroptosis needs to be investigated. The literature shows that the stabilizationof HIF-1α with PHD inhibitors and the combination of antioxidants and iron chelators are potential therapeuticdirections. In the future, the optimal use time and dose of inhibitors should be studied to improve the efficacy.

The role of glutathione peroxidase 4 in neuronal ferroptosis and its therapeutic potential in ischemic and hemorrhagic stroke

Ferroptosis is a type of cell death that depends on iron and is driven by lipid peroxidation, playing a crucial role in neuronal death during stroke. A central element in this process is the inactivation of glutathione peroxidase 4 (GPx4), an antioxidant enzyme that helps maintain redox balance by reducing lipid hydroperoxides. This review examines the critical function of GPx4 in controlling neuronal ferroptosis following ischemic and hemorrhagic stroke. We explore the mechanisms through which GPx4 becomes inactivated in various stroke subtypes. In strokes, excess glutamate depletes glutathione (GSH) and products of hemoglobin breakdown overwhelm GPx4. Studies using genetic models with GPx4 deficiency underscore its vital role in maintaining neuronal survival and function. We also consider new therapeutic approaches to enhance GPx4 activity, including novel small molecule activators, adjustments in GSH metabolism, and selenium supplementation. Additionally, we outline the potential benefits of combining these GPx4-focused strategies with other anti-ferroptotic methods like iron chelation and lipoxygenase inhibition for enhanced neuroprotection. Furthermore, we highlight the significance of understanding the timing of GPx4 inactivation during stroke progression to design effective therapeutic interventions.

HIF-1α Induced by Hypoxia Promotes Peripheral Nerve Injury Recovery Through Regulating Ferroptosis in DRG Neuron

Peripheral nerve injury (PNI) usually has a poor effect on functional recovery and severely declines the patient's quality of life. Our prior findings indicated that hypoxia remarkably promoted nerve regeneration of rats with sciatic nerve transection. However, the underlying molecular mechanisms of hypoxia in functional recovery of PNI still remain elusive. In this research, we tried to explain the functional roles and mechanisms of hypoxia and the hypoxia-inducible factor-1α (HIF-1α) in PNI. Our results indicated that hypoxia promoted proliferation and migration of dorsal root ganglia (DRG) and increased the expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Mechanistically, hypoxia suppressed ferroptosis through activating HIF-1α in DRG neurons. Gain and loss of function studies were performed to evaluate the regulatory roles of HIF-1α in ferroptosis and neuron recovery. The results revealed that up-regulation of HIF-1α enhanced the expression of solute carrier family membrane 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) and increased the contents of cysteine and glutathione, while inhibiting the accumulation of reactive oxygen species (ROS). Our findings provided novel light on the mechanism of ferroptosis involved in PNI and manifest hypoxia as a potential therapeutic strategy for PNI recovery.

A guide to ferroptosis, the biological rust of cellular membranes

Unprotected iron can rust due to oxygen exposure. Similarly, in our body, oxidative stress can kill cells in an iron-dependent manner, which can give rise to devastating diseases. This type of cell death is referred to as ferroptosis. Generally, ferroptosis is defined as an iron-catalyzed form of regulated necrosis that occurs through excessive peroxidation of polyunsaturated fatty acids within cellular membranes. This review summarizes how ferroptosis is executed by a rather primitive biochemical process, under tight regulation of lipid, iron, and redox metabolic processes. An overview is given of major classes of ferroptosis inducers and inhibitors, and how to detect ferroptosis. Finally, its detrimental role in disease is briefly discussed.

Dietary Selenium Insufficiency Induces Cardiac Inflammatory Injury in Chicks

BACKGROUND

Laying hens undergo intensive metabolism and are vulnerable to cardiac insults. Previous research demonstrated overt heart disorders of broiler chickens induced by dietary Se deficiency.

OBJECTIVES

This study aimed to reveal effects and mechanism of dietary Se insufficiency on cardiac injuries of egg-type chicks in their early life.

METHODS

White Leghorn chicks (0-d-old, female) were fed a corn-soy, Se-insufficient basal diet (BD, 0.05 mg Se/kg; n = 11) or the BD supplemented with 0.3 mg Se/kg (as sodium selenite; n = 8) for 35 d. Cardiac tissues were collected at the end of study for histology and to determine its relationship with heart Se contents, selenoprotein expression profiles, antioxidant and inflammatory status, and the Toll-like receptor 4/extracellular signal-regulated kinases/p38 map kinase/c-Jun N-terminal kinase (TLR4/ERK/P38/JNK) pathway.

RESULTS

Compared with those fed 0.35 mg Se/kg, chicks fed BD had significantly lower body weights and average daily gain, and 28% lower heart Se, and developed cardiac mononuclear inflammatory cell infiltration, along with elevated (P < 0.05) serum concentrations of creatine kinase, aldolase, and interleukin-1 (IL-1). The BD decreased (P < 0.05) body weight and heart glutathione contents and expression of selenoproteins but increased (P < 0.05) heart concentrations of malondialdehyde and reactive oxygen species. These changes were associated with increased (P < 0.05) mRNA and/or protein concentrations of cyclooxygenases, lipoxygenase-12, cytokines (IL-1β), nuclear factor (NF) κB subunit, chemokines, and receptors (CCL20, CXCR1, and CXCLI2) and increased (P < 0.1) TLR4/ERK /P38/JNK in the heart of Se-insufficient chicks.

CONCLUSIONS

Dietary Se insufficiency induces infiltration of mononuclear inflammatory cells in the heart of egg-type chicks. This cardiac injury was mediated by decreased functional expressions of selenoproteins, which resulted in apparent elevated oxidative stress and subsequent activations of the TLR4 pathway and NF κB.

Mechanism of motoneuronal and pyramidal cell death in amyotrophic lateral sclerosis and its potential therapeutic modulation

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder clinically characterized by muscle atrophy and progressive paralysis. Loss of motoneurons and pyramidal cells is thought to be the center piece of the complex and multifaceted ALS pathology, however, the exact mechanisms laying behind motoneuronal cell death in the spinal cord and motor cortex are still unknown. It was originally proposed that apoptosis plays a fundamental role in motoneuronal demise, nonetheless, later it became clear that other forms of regulated cell death, including necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death, may also contribute to motoneuron loss. Over the past years, multiple studies aimed to improve our understanding of the contributory role of these mechanisms as well as to offer novel targets for potential therapeutic interventions. The pharmacological inhibition of the ferroptotic pathway and the modulation of the autophagic machinery seem to have particularly promising effects, reducing motoneuron loss and slowing disease progression in transgenic models of ALS. Nevertheless, the potential beneficial effects of necroptosis-targeting interventions were mostly disproven in the latest studies. In this review we aim to summarize the current view on regulated cell death mechanisms that lead to motoneuronal and pyramidal cell degeneration in ALS and showcase their applicability as future drug targets.

Therapeutic exploitation of ferroptosis

Pathological breakdown of membrane lipids through excessive lipid peroxidation (LPO) was first described in the mid-20th century and is now recognized as a form of regulated cell death, dubbed ferroptosis. Accumulating evidence unveils how metabolic regulation restrains peroxidation of phospholipids within cellular membranes, thereby impeding ferroptosis execution. Unleashing these metabolic breaks is currently therapeutically explored to sensitize cancers to ferroptosis inducing anti-cancer therapies. Reversely, these natural ferroptotic defense mechanisms can fail resulting in pathological conditions or diseases such as ischemia-reperfusion injury, multi-organ dysfunction, stroke, infarction, or neurodegenerative diseases. This minireview outlines current ferroptosis-inducing anti-cancer strategies and highlights the detection as well as the therapeutic targeting of ferroptosis in preclinical experimental settings. Herein, we also briefly summarize observations related to LPO, iron and redox deregulation in patients that might hint towards ferroptosis as a contributing factor.

NRF2 activation suppresses motor neuron ferroptosis induced by the SOD1G93A mutation and exerts neuroprotection in amyotrophic lateral sclerosis

The progressive neurodegenerative disease amyotrophic lateral sclerosis (ALS) is caused by a decline in motor neuron function, resulting in worsened motor impairments, malnutrition, respiratory failure and mortality, and there is a lack of effective clinical treatments. The exact mechanism of motor neuronal degeneration remains unclear. Previously, we reported that ferroptosis, which is characterized by the accumulation of lipid peroxide and glutathione depletion in an iron-dependent manner, contributed to motor neuronal death in ALS cell models with the hSOD1^G93A (human Cu/Zn-superoxide dismutase) gene mutation. In this study, we further explored the role of ferroptosis in motor neurons and its regulation in mutant hSOD1^G93A cell and mouse models. Our results showed that ferroptosis was activated in hSOD1^G93A NSC-34 cells and mouse models, which was accompanied by decreased nuclear retention of nuclear factor erythroid 2-related factor 2 (NRF2) and downregulation of solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) levels. Moreover, RTA-408, an NRF2 activator, inhibited ferroptosis in hSOD1^G93A NSC-34 cells by upregulating the protein expression of SLC7A11 and GPX4. Moreover, hSOD1^G93A mice treated with RTA-408 showed obvious improvements in body weight and motor function. Our study demonstrated that ferroptosis contributed to the toxicity of motor neurons and that activating NRF2 could alleviate neuronal degeneration in ALS with the hSOD1^G93A mutation.

BL-918, a small-molecule activator of ULK1, induces cytoprotective autophagy for amyotrophic lateral sclerosis therapy

Amyotrophic lateral sclerosis (ALS) is one of the most common fatal neurodegenerative diseases in adults. ALS pathogenesis is associated with toxic SOD1 aggregates generated by mutant SOD1. Since autophagy is responsible for the clearance of toxic protein aggregates including SOD1 aggregates, autophagy induction has been considered as a potential strategy for treating ALS. Autophagic signaling is initiated by unc-51 like autophagy activating kinase 1 (ULK1) complex. We previously identified that BL-918 as a specific ULK1 activator, which exerted cytoprotective effect against Parkinson's disease in vitro and in vivo. In this study we investigated whether BL-918 exerted a therapeutic effect against ALS, and characterized its pharmacokinetic profile in rats. In hSODG93A-NSC34 cells, treatment with BL-918 (5, 10 μM) dose-dependently induced ULK1-dependent autophagy, and eliminated toxic SOD1 aggregates. In SODG93A mice, administration of BL-918 (40, 80 mg/kg, b.i.d., i.g.) dose-dependently prolonged lifespan and improved the motor function, and enhanced the clearance of SOD1 aggregates in spinal cord and cerebral cortex through inducing autophagy. In the pharmacokinetic study conducted in rats, we found BL-918 and its 2 metabolites (M8 and M10) present in spinal cord and brain; after intragastric and intravenous administration, BL-918 reached the highest blood concentration compared to M8 and M10. Collectively, ULK1 activator BL-918 displays a therapeutic potential on ALS through inducing cytoprotective autophagy. This study provides a further clue for autophagic dysfunction in ALS pathogenesis.