A natural polyphenol activates and enhances GPX4 to mitigate amyloid-β induced ferroptosis in Alzheimer's disease

Ultrasmall iron-gallic acid coordination polymer nanoparticles for scavenging ROS and suppressing inflammation in tauopathy-induced Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder globally, with no effective treatment available yet. A crucial pathological hallmark of AD is the accumulation of hyperphosphorylated tau protein, which is deteriorated by reactive oxygen species (ROS) and neuroinflammation in AD progression. Thus, alleviation of ROS and inflammation has become a potential therapeutic strategy in many studies. Herein, we reported ultrasmall coordination polymer nanoparticles formed by ferric ions and gallic acid (Fe-GA CPNs), which owned antioxidant and anti-inflammation properties for AD therapeutics. The facilely prepared Fe-GA CPNs exhibited remarkable superoxide dismutase-like, peroxidase-like enzyme activity, and ROS eliminating ability with great water solubility, compared with gallic acid. We demonstrated that Fe-GA CPNs effectively relieved oxidative stress, ameliorated inflammation by modulating microglial polarization towards anti-inflammation phenotype, and reduced hyperphosphorylated tau protein levels. Furthermore, Fe-GA CPNs treatment significantly improved cognitive function in tauopathy-induced AD rats, and achieved a neuroprotective effect against AD pathology. This study highlights the potential of coordination polymer nanoparticles as promising therapeutic candidates for AD and other tau-related neurodegenerative diseases.

The role of ferritinophagy and ferroptosis in Alzheimer's disease

Iron is a crucial mineral element within human cells, serving as a pivotal cofactor for diverse biological enzymes. Ferritin plays a crucial role in maintaining iron homeostasis within the body through its ability to sequester and release iron. Ferritinophagy is a selective autophagic process in cells that specifically facilitates the degradation of ferritin and subsequent release of free iron, thereby regulating intracellular iron homeostasis. The nuclear receptor coactivator 4 (NCOA4) serves as a pivotal regulator in the entire process of ferritinophagy, facilitating its binding to ferritin and subsequent delivering to lysosomes for degradation, thereby enabling the release of free iron. The free iron ions within the cell undergo catalysis through the Fenton reaction, resulting in a substantial generation of reactive oxygen species (ROS). This process induces lipid peroxidation, thereby stimulating a cascade leading to cellular tissue damage and subsequent initiation of ferroptosis. Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive deterioration of emotional memory and cognitive function, accompanied by mental and behavioral aberrations. The pathology of the disease is characterized by aberrant deposition of amyloid β-protein (Aβ) and hyperphosphorylated tau protein. It has been observed that evident iron metabolism disorders and accumulation of lipid peroxides occur in AD, indicating a significant impact of ferritinophagy and ferroptosis on the pathogenesis and progression of AD. This article elucidates the process and mechanism of ferritinophagy and ferroptosis, investigating their implications in AD to identify novel targets for therapeutic intervention.

Potential role and therapeutic implications of glutathione peroxidase 4 in the treatment of Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder with a complex and incompletely understood pathogenesis. Despite extensive research, a cure for Alzheimer's disease has not yet been found. Oxidative stress mediates excessive oxidative responses, and its involvement in Alzheimer's disease pathogenesis as a primary or secondary pathological event is widely accepted. As a member of the selenium-containing antioxidant enzyme family, glutathione peroxidase 4 reduces esterified phospholipid hydroperoxides to maintain cellular redox homeostasis. With the discovery of ferroptosis, the central role of glutathione peroxidase 4 in anti-lipid peroxidation in several diseases, including Alzheimer's disease, has received widespread attention. Increasing evidence suggests that glutathione peroxidase 4 expression is inhibited in the Alzheimer's disease brain, resulting in oxidative stress, inflammation, ferroptosis, and apoptosis, which are closely associated with pathological damage in Alzheimer's disease. Several therapeutic approaches, such as small molecule drugs, natural plant products, and non-pharmacological treatments, ameliorate pathological damage and cognitive function in Alzheimer's disease by promoting glutathione peroxidase 4 expression and enhancing glutathione peroxidase 4 activity. Therefore, glutathione peroxidase 4 upregulation may be a promising strategy for the treatment of Alzheimer's disease. This review provides an overview of the gene structure, biological functions, and regulatory mechanisms of glutathione peroxidase 4, a discussion on the important role of glutathione peroxidase 4 in pathological events closely related to Alzheimer's disease, and a summary of the advances in small-molecule drugs, natural plant products, and non-pharmacological therapies targeting glutathione peroxidase 4 for the treatment of Alzheimer's disease. Most prior studies on this subject used animal models, and relevant clinical studies are lacking. Future clinical trials are required to validate the therapeutic effects of strategies targeting glutathione peroxidase 4 in the treatment of Alzheimer's disease.

Hinokitiol ameliorates MASH in mice by therapeutic targeting of hepatic Nrf2 and inhibiting hepatocyte ferroptosis

BACKGROUND

Metabolic dysfunction-associated steatohepatitis (MASH), an advanced stage of metabolic dysfunction-associated steatotic liver disease (MASLD), still lacks approved effective clinical drugs. Ferroptosis, a form of regulated cell death driven by excessive iron accumulation and uncontrollable lipid peroxidation, has been proven to be a trigger of inflammation and initiation of steatohepatitis. The pathogenic interplay is modulated by oxidative stress, while the Nrf2-mediated antioxidant response plays a regulatory role in ferroptosis. Phytochemical hinokitiol (Hino) has demonstrated positive efficacy in hepatocellular carcinoma (HCC) in the reported work, but it remains unknown whether its therapeutic effect attributes to delaying the progress of steatohepatitis to HCC.

PURPOSE

This work aimed to systemically investigate the significance of ferroptosis in the pathogenesis of MASH and to demonstrate that Hino, a bioactive monoterpene compound, attenuates the primary pathological characteristics of MASH via promotion of Nrf2/GPX4 signaling.

METHODS

In this work, a MASH model was established using the high-fat/high-cholesterol (HFHC) diet-fed in vivo and palmitic acid/oleic acid (PO)-stimulated hepatocytes in vitro. Biochemical indexes, pathological analysis, western blot, PCR assay, energy metabolic phenotype, molecular docking, and confirmatory assays were performed comprehensively to reveal the key link between the Nrf2/GPX4 axis and the treatment of MASH.

RESULTS

Under MASH conditions with increased oxidative stress, we show that Nrf2 was remarkable downregulated in HFHC diet-fed mice and PO-managed hepatocytes. Mechanistically, hepatic upregulation of Nrf2 through phytochemical Hino supplementation inhibited ferroptosis, enhanced lipid metabolism, and thereby alleviated hepatic steatosis, inflammation, and fibrosis. Conversely, silencing Nrf2 in hepatocytes further promoted the accumulation of key markers of ferroptosis and aggravated MASH phenotypes.

CONCLUSION

Increased ferroptosis promoted steatosis which further drove inflammation and hepatic fibrosis. Our results suggested the significance of Nrf2 in ameliorating MASH, which was regulated through Hino. Thus, targeted inhibition of ferroptosis through Hino administration is a feasible and effective approach for treating MASH.

Ginger leaf polyphenols mitigate β-amyloid toxicity via JNK/FOXO pathway activation in Caenorhabditis elegans

β-Amyloid (Aβ) aggregation is the major pathological feature of Alzheimer's disease (AD), resulting in oxidative stress and further exacerbating Aβ aggregation. Ginger leaf polyphenols (GLP) have been found to possess antioxidant activity, evidencing their potential in addressing AD. GLP is mainly composed of 12 polyphenols, 8 organic acids, and 6 glycosides, of which polyphenols are predominantly composed of apigenin, kaempferol, and quercetin derivatives. Moreover, GLP alleviates reproductive toxicity, longevity toxicity, and neurotoxicity induced by Aβ via regulating the antioxidase system in Caenorhabditis elegans. As shown by the network pharmacology results, GLP might activate the JNK/Foxo signaling pathway to regulate the antioxidase system, which was evidenced by the up-regulation of gene expression levels of jnk-1, daf-16, sod-3, and hsp-16.2. Overall, GLP might be a potential antioxidant for combating AD.

Mechanisms and Therapeutic Potential of GPX4 in Pain Modulation

Pain, a complex symptom encompassing both sensory and emotional dimensions, constitutes a significant global public health issue. Oxidative stress is a pivotal factor in the complex pathophysiology of pain, with glutathione peroxidase 4 (GPX4) recognized as a crucial antioxidant enzyme involved in both antioxidant defense mechanisms and ferroptosis pathways. This review systematically explores GPX4's functions across various pain models, including neuropathic, inflammatory, low back, and cancer-related pain. Specifically, the focus includes GPX4's physiological roles, antioxidant defense mechanisms, regulation of ferroptosis, involvement in signal transduction pathways, and metabolic regulation. By summarizing current research, we highlight the potential of GPX4-targeted therapies in pain management.

A Redox-Triggered Polymeric Nanoparticle for Disrupting Redox Homeostasis and Enhanced Ferroptosis

Cancer cells possess an efficient redox system, enabling them to withstand oxidative damage induced by treatments, especially in hypoxia areas and ferroptosis can disrupt redox homeostasis in cancer cell. Herein, GSH-sensitive nanoparticles are constructed that induce ferroptosis by long-lasting GSH depletion and enhanced PDT. Carbonic anhydrase IX inhibitor, protoporphyrin IX (Por) complexed with Fe and epirubicin (EPI) are grafted to hyaluronic acid (HA) via disulfide bonds to obtain HSPFE and loaded xCT inhibitor SAS for fabricating SAS@HSPFE which is actively targeted to deep hypoxic tumor cells, and explosively releasing EPI, Por-Fe complex and SAS due to at high GSH concentration. Specifically, SAS inhibited the GSH biosynthesis, and the generation of ROS by Por and the involvement of Fe2+ in the Fenton reaction jointly facilitates oxidative stress. Besides, Fe2+ reacted with excess H2O2 to produce O2, which continuously fuels PDT. GPX4 and SLC7A11 related to antioxidant defense are down-regulated, while ACSL4 and TFRC promoting lipid peroxidation and ROS accumulation are up-regulated, which enhanced ferroptosis by amplifying oxidative stress and suppressing antioxidant defense. SAS@HSPFE NPs revealed highly efficient antitumor effect in vivo study. This study provides a novel approach to cancer treatment by targeting redox imbalance.

The Role of Gut Microbiota in the Neuroprotective Effects of Selenium in Alzheimer's Disease

The objective of the present review was to provide a timely update on the molecular mechanisms underlying the beneficial role of Se in Alzheimer's disease pathogenesis, and discuss the potential role of gut microbiota modulation in this neuroprotective effect. The existing data demonstrate that selenoproteins P, M, S, R, as well as glutathione peroxidases and thioredoxin reductases are involved in regulation of Aβ formation and aggregation, tau phosphorylation and neurofibrillary tangles formation, as well as mitigate the neurotoxic effects of Aβ and phospho-tau. Correspondingly, supplementation with various forms of Se in cellular and animal models of AD was shown to reduce Aβ formation, tau phosphorylation, reverse the decline in brain antioxidant levels, inhibit neuronal oxidative stress and proinflammatory cytokine production, improve synaptic plasticity and neurogenesis, altogether resulting in improved cognitive functions. In addition, most recent findings demonstrate that these neuroprotective effects are associated with Se-induced modulation of gut microbiota. In animal models of AD, Se supplementation was shown to improve gut microbiota biodiversity with a trend to increased relative abundance of Lactobacillus, Bifidobacterium, and Desulfivibrio, while reducing that of Lachnospiracea_NK4A136, Rikenella, and Helicobacter. Moreover, the relative abundance of Se-affected taxa was significantly associated with Aβ accumulation, tau phosphorylation, neuronal oxidative stress, and neuroinflammation, indicative of the potential role of gut microbiota to mediate the neuroprotective effects of Se in AD. Hypothetically, modulation of gut microbiota along with Se supplementation may improve the efficiency of the latter in AD, although further detailed laboratory and clinical studies are required.

Multifunctional hydroxyquinoline-derived turn-on fluorescent probe for Alzheimer's disease detection and therapy

Understanding molecular motifs that can interfere with amyloid fibrillation through non-covalent interactions is essential for addressing abnormal protein aggregation and associated human diseases. The pursuit of efficient diagnostic and treatment approaches for Alzheimer's disease (AD) has resulted in the development of M8HQ, a multifaceted small molecule turn-on probe derived from 8-hydroxyquinoline with versatile capabilities. M8HQ shows a strong affinity for amyloid beta (Aβ) fibrils, and its ability to target lysosomes enhances therapeutic precision by localizing within these organelles. This localization is essential for restoring cellular balance and maintaining LAMP1 expression, both of which are crucial for addressing AD. It also displays the ability to disaggregate Aβ fibrils and inhibit their formation, thus addressing therapeutic processes in AD progression. M8HQ further blocks reactive oxygen species (ROS)-mediated apoptosis, providing neuroprotective effects. Additionally, it chelates metal ions like Cu(II) and Fe(III), mitigating metal-induced aggregation and oxidative stress. Molecular docking and simulation studies have elucidated the interactions between M8HQ and Aβ, confirming its binding efficacy and stability. These combined properties highlight M8HQ's potential as a comprehensive diagnostic and therapeutic tool for AD.

Proteomic alteration in catalpol treatment of Alzheimer's disease by regulating HSPA5/ GPX4

Alzheimer's disease (AD), a chronic and progressive neurodegenerative disease, is characterized by the deposition of extracellular amyloid plaques and intracellular neurofibrillary tangles. Conventional anti-AD drugs exhibit high toxicity and adversely impact patients' quality of life. Therefore, novel treatments for AD are urgently required. In recent years, targeting ferroptosis through the modulation of lipid oxidation has emerged as a new approach in the treatment of neurodegenerative diseases. Catalpol, an iridoid glycoside isolated from the roots of Rehmannia glutinosa, has exhibited anti-inflammatory, antioxidant, and neuroprotective properties. Therefore, in this study, we investigated the protective effects and associated underlying mechanisms of catalpol in an APP/PS1 AD mouse model. Catalpol treatment significantly improved the cognitive capabilities and decreased Aβ1-40 and Aβ1-42 levels in mice. Morphological testing revealed that catalpol prevented neuronal loss and reduced mitochondrial swelling in the hippocampal CA1 region. Proteomic studies identified 2495 hippocampus proteins whose expression was associated with the mechanism of catalpol treatment, including 44 ferroptosis-related proteins. Bioinformatic analysis revealed that catalpol significantly increased the protein levels of HSPA5 and GPX4 in the hippocampus. Additionally, catalpol modulated biological pathways related to apoptosis, cytokine-mediated signaling, and ferroptosis. The considerable upregulation of HSPA5 and GPX4 with catalpol was further confirmed through western blotting. Catalpol exhibited neuroprotective effects through a variety of mechanisms. Among these, HSPA5 and GPX4, associated with ferroptosis, may play key roles in AD pathogenesis, and present promising therapeutic targets.

Dual emission chiral carbon dots as fluorescent probe for fast chiral recognition of tryptophan enantiomers

BACKGROUND

Chirality is an essential property of nature. Chiral recognition is of great significance to life sciences, pharmaceutical industry, food analysis, and so on. Chiral carbon dots (CCDs), as green nanomaterials, have great prospects in chiral sensing. However, CCDs with enantioselectivity for tryptophan (Trp) enantiomers are scarce. Moreover, most chiral sensing platforms depend on the difference of fluorescence intensity at the same emission wavelength to identify enantiomers, it is still a challenge to distinguish enantiomers by the positions of fluorescent emission peaks.

RESULTS

Novel CCDs with specific chiral recognition ability for Trp enantiomers are synthesized using l-lysine and l-cysteine as precursors. The CCDs have two fluorescent emission peaks at 390 nm and 450 nm. Interestingly, the fluorescence intensity of CCDs at 390 nm enhances obviously on the addition of L-Trp, while it enhances slightly at 450 nm in the presence of D-Trp. This chiral sensing system not only can identify Trp enantiomers according to fluorescence intensity, but also achieves the distinguishment depending on emission wavelength. The enantioselectivity (IL/ID) reaches 4.5 when the concentration of Trp enantiomer is 1 mM. This chiral sensing platform not only can be used for quantitative analysis of D-Trp and L-Trp, but also can be used for determining the enantiomeric excess of racemates. The chiral recognition mechanism is investigated by molecular simulation. It is found that L-Trp has higher binding energy with CCDs.

SIGNIFICANCE

This work presents a novel kind of CCDs with special chiral recognition performance for Trp enantiomers, and opens the door to identify chiral isomers according to wavelength difference, which has profound significance for the development of chiral sensing platforms, and may provide inspirations for the design of novel CCDs with excellent chiral recognition performance.

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.

Iron-associated lipid peroxidation in Alzheimer's disease is increased in lipid rafts with decreased ferroptosis suppressors, tested by chelation in mice

INTRODUCTION

Iron-mediated cell death (ferroptosis) is a proposed mechanism of Alzheimer's disease (AD) pathology. While iron is essential for basic biological functions, its reactivity generates oxidants which contribute to cell damage and death.

METHODS

To further resolve mechanisms of iron-mediated toxicity in AD, we analyzed post mortem human brain and ApoEFAD mice.

RESULTS

AD brains had decreased antioxidant enzymes, including those mediated by glutathione (GSH). Subcellular analyses of AD brains showed greater oxidative damage and lower antioxidant enzymes in lipid rafts, the site of amyloid processing, than in the non-raft membrane fraction. Apolipoprotein E ε4 carriers had lower lipid raft yield with greater membrane oxidation. The hypothesized role of iron in AD pathology was tested in ApoEFAD mice by iron chelation with deferoxamine, which decreased fibrillar amyloid and lipid peroxidation, together with increased GSH-mediated antioxidants.

DISCUSSION

These novel molecular pathways highlight iron-mediated damage to lipid rafts during AD.

HIGHLGHTS

Alzheimer's disease (AD) brains have numerous markers for ferroptosis, including increased lipid peroxidation, reduced antioxidant levels, and increased iron storage. Lipid rafts in AD cases have increased oxidative damage and reduced antioxidant enzyme levels and activity which are most severe in apolipoprotein E ε4 carriers. Neuronal markers are correlated with lipid peroxidation, antioxidant defense, and iron signaling proteins suggesting that neuronal loss is linked to these events. Chelation of iron in the early-onset familial AD model reduces iron-mediated lipid peroxidation and fibrillar amyloid.

Osmundacetone ameliorates Alzheimer's-like pathologies by inhibiting β-amyloid fibrillation, oxidative damage and neuroinflammation in APP/PS1 transgenic mice

BACKGROUND

β-Amyloid (Aβ) fibrillation is critical for Aβ deposition and cytotoxicity during the progression of Alzheimer's disease (AD). Consequently, anti-Aβ monoclonal antibody drugs targeting Aβ oligomers and aggregation are considered potential therapeutic strategies for AD treatment. Similar to the working mechanisms of anti-Aβ monoclonal antibody drugs, our study identified osmundacetone (OAC), a small-molecule compound isolated from the traditional Chinese medicine Rhizoma Osmundae, as exerting anti-AD effects by targeting Aβ.

PURPOSE

This study sought to determine whether OAC influences the Aβ burden in APP/PS1 mice and to identify potential regulatory mechanisms.

METHODS

Five-month-old APP/PS1 mice were injected intraperitoneally with OAC at a dose of 1 mg/kg for 12 weeks. The cognitive functions of the mice were assessed via the Morris water maze test and the open field test. Osmundacetone was analyzed via molecular docking, an isothermal dose‒response fingerprint-cellular context thermal shift assay, a thioflavine T fluorescence assay, and an atomic force microscopy assay to analyze the effects of OAC on Aβ fibrillation. Immunofluorescence, immunoblotting, and immunohistochemistry were used to assess Aβ clearance, AD pathology, oxidative stress, and inflammatory responses.

RESULTS

The innovative biochemical and physical data illustrated that the ability of OAC to inhibit Aβ fibrillation was accomplished by binding directly to Aβ, which differed from the majority of previously reported natural polyphenols that modulate the Aβ content and structure in an indirect manner. The inhibition of Aβ fibrosis by OAC subsequently promoted Aβ lysosomal degradation, resulting in a decreased Aβ burden in APP/PS1 mice. Furthermore, OAC treatment inhibited oxidative damage by upregulating glutathione peroxidase expression and attenuated the production of inflammatory factors by downregulating nuclear factor-kB phosphorylation in APP/PS1 mice.

CONCLUSION

These findings demonstrate, for the first time, that OAC could reduce the brain Aβ burden in APP/PS1 mice by inhibiting Aβ fibrillation through direct binding to Aβ and improve cognitive dysfunction by attenuating oxidative damage and neuroinflammation. These findings indicate that OAC may be a promising candidate for the treatment of AD.

Iron homeostasis and neurodegeneration in the ageing brain: Insight into ferroptosis pathways

Ageing is a major risk factor for various chronic diseases and offers a potential target for developing novel and broadly effective preventatives or therapeutics for age-related conditions, including those affecting the brain. Mechanisms contributing to ageing have been summarized as the hallmarks of ageing, with iron imbalance being one of the major factors. Ferroptosis, an iron-mediated lipid peroxidation-induced programmed cell death, has recently been implicated in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Addressing ferroptosis offers both opportunities and challenges for treating neurodegenerative diseases, though the specific mechanisms remain unclear. This research explores the key processes behind how ferroptosis contributes to brain ageing, with a focus on the complex signaling networks that are involved. The current article aims to uncover that how ferroptosis, a specific type of cell death, may drive age-related changes in the brain. Additionally, the article also unveils its role in neurodegenerative diseases, discussing how understanding these mechanisms could open up new therapeutic avenues.

Different amyloid β42 preparations induce different cell death pathways in the model of SH-SY5Y neuroblastoma cells

Amyloid β42 (Aβ42) plays a decisive role in the pathology of Alzheimer's disease. The Aβ42 peptide can aggregate into various supramolecular structures, with oligomers being the most toxic form. However, different Aβ species that cause different effects have been described. Many cell death pathways can be activated in connection with Aβ action, including apoptosis, necroptosis, pyroptosis, oxidative stress, ferroptosis, alterations in mitophagy, autophagy, and endo/lysosomal functions. In this study, we used a model of differentiated SH-SY5Y cells and applied two different Aβ42 preparations for 2 and 4 days. Although we found no difference in the shape and size of Aβ species prepared by two different methods (NaOH or NH4OH for Aβ solubilization), we observed strong differences in their effects. Treatment of cells with NaOH-Aβ42 mainly resulted in damage of mitochondrial function and increased production of reactive oxygen species, whereas application of NH4OH-Aβ42 induced necroptosis and first steps of apoptosis, but also caused an increase in protective Hsp27. Moreover, the two Aβ42 preparations differed in the mechanism of interaction with the cells, with the effect of NaOH-Aβ42 being dependent on monosialotetrahexosylganglioside (GM1) content, whereas the effect of NH4OH-Aβ42 was independent of GM1. This suggests that, although both preparations were similar in size, minor differences in secondary/tertiary structure are likely to strongly influence the resulting processes. Our work reveals, at least in part, one of the possible causes of the inconsistency in the data observed in different studies on Aβ-toxicity pathways.

Implications of liquid-liquid phase separation and ferroptosis in Alzheimer's disease

Neuronal cell demise represents a prevalent occurrence throughout the advancement of Alzheimer's disease (AD). However, the mechanism of triggering the death of neuronal cells remains unclear. Its potential mechanisms include aggregation of soluble amyloid-beta (Aβ) to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFTs), neuroinflammation, ferroptosis, oxidative stress, liquid-liquid phase separation (LLPS) and metal ion disorders. Among them, ferroptosis is an iron-dependent lipid peroxidation-driven cell death and emerging evidences have demonstrated the involvement of ferroptosis in the pathological process of AD. The sensitivity to ferroptosis is tightly linked to numerous biological processes. Moreover, emerging evidences indicate that LLPS has great impacts on regulating human health and diseases, especially AD. Soluble Aβ can undergo LLPS to form liquid-like droplets, which can lead to the formation of insoluble amyloid plaques. Meanwhile, tau has a high propensity to condensate via the mechanism of LLPS, which can lead to the formation of NFTs. In this review, we summarize the most recent advancements pertaining to LLPS and ferroptosis in AD. Our primary focus is on expounding the influence of Aβ, tau protein, iron ions, and lipid oxidation on the intricate mechanisms underlying ferroptosis and LLPS within the domain of AD pathology. Additionally, we delve into the intricate cross-interactions that occur between LLPS and ferroptosis in the context of AD. Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for AD.

Regulation of redox enzymes by nutraceuticals: a review of the roles of antioxidant polyphenols and peptides

Redox enzymes are essential components of the cellular defence system against oxidative stress, which is a common factor in various diseases. Therefore, understanding the role of bioactive nutraceuticals in modulating the activity of these enzymes holds immense therapeutic potential. This paper provides a comprehensive review of the regulation of redox enzymes in cell and animal models by food-derived bioactive nutraceuticals, focusing on polyphenols and peptides. Specifically, this paper discusses the regulation of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), NAPDH oxidase, xanthine oxidase (XO), myeloperoxidase (MPO), and haem oxygenase (HO) in cell and animal models. Polyphenols, which are abundant in fruits, vegetables, and beverages, have diverse antioxidant properties, including direct scavenging of reactive oxygen species and regulation of transcription factors such as nuclear factor erythroid 2-related factor 2, which leads to the increased expression of the redoxenzymes SOD, HO, and GPx. Similarly, bioactive peptides from various food proteins can enhance antioxidative enzyme activity by regulating gene expression and directly activating the enzyme CAT. In other cases, an antioxidative response requires the downregulation or inhibition of the redox enzymes XO, MPO, and NAPDH oxidase. This paper highlights the potential of bioactive nutraceuticals in mitigating oxidative stress-related diseases and their mechanisms in modulating the redox enzyme expression or activity. Furthermore, the review highlights the need for further research to uncover new therapeutic strategies using nutraceuticals for enhancing cellular antioxidant defence mechanisms and improving health outcomes.

Astrocyte-derived lactoferrin inhibits neuronal ferroptosis by reducing iron content and GPX4 degradation in APP/PS1 transgenic mice

Increased astrocytic lactoferrin (Lf) expression was observed in the brains of elderly individuals and Alzheimer's disease (AD) patients. Our previous study revealed that astrocytic Lf overexpression improved cognitive capacity by facilitating Lf secretion to neurons to inhibit β-amyloid protein (Aβ) production in APP/PS1 mice. Here, we further discovered that astrocytic Lf overexpression inhibited neuronal loss by decreasing iron accumulation and increasing glutathione peroxidase 4 (GPX4) expression in neurons within APP/PS1 mice. Furthermore, human Lf (hLf) treatment inhibited ammonium ferric citrate (FAC)-induced ferroptosis by chelating intracellular iron. Additionally, machine learning analysis uncovered a correlation between Lf and GPX4. hLf treatment boosted low-density lipoprotein receptor-related protein 1 (LRP1) internalization and facilitated its interaction with heat shock cognate 70 (HSC70), thereby inhibiting HSC70 binds to GPX4, and eventually attenuating GPX4 degradation and FAC-induced ferroptosis. Overall, astrocytic Lf overexpression inhibited neuronal ferroptosis through two pathways: reducing intracellular iron accumulation and promoting GPX4 expression via inhibiting chaperone-mediated autophagy (CMA)-mediated GPX4 degradation. Hence, upregulating astrocytic Lf expression is a promising strategy for combating AD.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Olive Oil Industry By-Products as a Novel Source of Biophenols with a Promising Role in Alzheimer Disease Prevention

This review explores the potential health benefits and applications of phenolic secoiridoids derived from olive oil by-products in the prevention of Alzheimer's disease (AD). As reviewed herein, polyphenols, such as epigallocatechin-3-gallate, epicatechin, and resveratrol, show in vitro and in vivo antioxidant, anti-inflammatory, and neuroprotective properties, and are particularly relevant in the context of AD, a leading cause of dementia globally. The olive oil industry, particularly in the Mediterranean region, produces significant amounts of waste, including leaves, pomace, and wastewater, which pose environmental challenges but also offer an untapped source of bioactive compounds. Despite promising in vitro and in vivo studies indicating that olive-derived polyphenols, such as oleuropein and hydroxytyrosol, may mitigate AD pathology, human clinical trials remain limited. The variability in extraction methods and the complex nature of AD further complicate research. Future studies should focus on standardizing the protocols and conducting robust clinical trials to fully assess the therapeutic potential of these compounds. This approach not only supports the development of new treatments for AD but also promotes environmental sustainability by valorizing olive oil industry waste.

The Potential Effects of Red Wine and Its Components on Neurocognitive Disorders: A Narrative Review

BACKGROUND

The aging population is associated with a net increase in the incidence and prevalence of chronic-degenerative diseases, particularly neurocognitive disorders. Therefore, the identification of preventative strategies to restrain the burden of such chronic conditions is of key relevance. Red wine and its components have accumulated evidence regarding their positive effects in terms of neurological pathologies associated with neurocognitive symptoms.

METHODS

Based on this background, the present narrative review aims to summarize the state-of-the-art evidence on the effects of red wine and its components on neurocognitive disorders in both preclinical and clinical settings.

RESULTS

The main findings highlight a protective effect of wine polyphenols present in red wine on dementia in different preclinical models of cognitive decline. The current translational clinical evidence remains uncertain, especially considering the risk-to-benefit ratio of alcohol consumption on brain health.

CONCLUSIONS

Given the overall health risks associated with red wine consumption and consistent with the prevailing guidelines in the literature, there is insufficient evidence to support light-to-moderate red wine consumption as an effective strategy for preventing these diseases. However, the largely preclinical findings on polyphenols derived from red wine remain of significant interest in this context.

A novel ferroptosis inhibitor, Thonningianin A, improves Alzheimer's disease by activating GPX4

Background: Ferroptosis, a recently unveiled iron-dependent form of cellular demise, has emerged as a pivotal process contributing to the pathology of Alzheimer's Disease (AD). Glutathione Peroxidase 4 (GPX4), a vital defense mechanism countering ferroptosis by nullifying lipid peroxides and maintaining cellular redox equilibrium, has garnered significant attention in AD. Thus, identifying ferroptosis inhibitors to target GPX4 activation may help mitigate neuronal damage and impede AD progression. Objectives: We aimed to screen potent ferroptosis inhibitors and investigate their mechanism of action and therapeutic potential in AD, as well as lay the groundwork for future research in this promising area of study. Methods: This study employed a natural compound library to screen potential ferroptosis inhibitors in RAS-selective lethal compounds 3 (RSL-3)-induced PC-12 cells. Ferroptosis was evaluated by examining the mitochondrial morphology and function, reactive oxygen species (ROS) production, and lipid peroxide levels. The ability to chelate iron and intracellular iron levels was determined by UHPLC-Q/TOF-MS/MS and PGSK staining, respectively. APP Swe/ind- or Tau P301L-overexpressing PC-12 cells, and Amyloid-β transgenic CL4176 and Tau transgenic BR5270 Caenorhabditis elegans were employed as cellular and animal models of AD. Results: Thonningianin A (ThA) was identified as a novel ferroptosis inhibitor, as demonstrated by augmented cellular viability, mitigated mitochondrial impairment, diminished lipid peroxides, iron levels, and ROS generation. Mechanistically, ThA binds with GPX4 and enhances the AMPK/Nrf2 signaling pathway to stimulate GPX4 activation, effectively inhibiting ferroptosis. Moreover, in cellular and Caenorhabditis elegans AD models, ThA substantially inhibits ferroptosis by reducing ROS, lipid peroxide generation, and iron accumulation. Furthermore, ThA significantly delays paralysis, ameliorates food-sensing deficits and increases worms' antioxidative capacity. Conclusion: ThA ameliorates AD by inhibiting neuronal ferroptosis mediated by GPX4 activation through its binding with GPX4 and the upregulation of the AMPK/Nrf2/GPX4 pathway.

Controlled preparation of tannic acid-derived carbonized dots and their use to inhibit amyloid aggregation and promote aggregate disaggregation

Tannic acid (TA)-derived carbon dots (TACDs) were synthesized for the first time via a solvothermal method using TA as one of the raw materials, which may effectively inhibit amyloid fibril aggregation and disaggregate mature fibril. The fluorescent property of TACDs were modulated by adjusting the ratio of TA to o-phenylenediamine (oPD), and TACDs fabricated with the precursor ratio as 1:1 showed the best fluorescent property. Circular dichroism spectra (CD) showed that the structure of β-sheet decreased as the concentration of TACDs increased. The inhibition efficiency, as confirmed by thioflavin T (ThT) and transmission electron microscopy (TEM), is extraordinary at 98.16%, whereas disaggregation efficiency is noteworthy at 97.97%, and the disaggregated lysozyme fibrils did not reaggregate after 7 days. More critically, TACDs can also alleviate the cellular toxicity caused by Aβ fibrils and improve cell viability. This work offers a new perspective on the design of scavengers for amyloid plaques.

Ferroptosis: A new strategy for targeting Alzheimer's disease

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

Melatonin Alleviates Osteoarthritis by Regulating NADPH Oxidase 4-Induced Ferroptosis and Mitigating Mitochondrial Dysfunction

Recent evidence indicates that the damaged regions in osteoarthritis are accompanied by the accumulation of iron ions. Ferroptosis, as an iron-dependent form of cell death, holds significant implications in osteoarthritis. Melatonin, a natural product with strong scavenging abilities against reactive oxygen species and lipid peroxidation, plays a crucial role in the treatment of osteoarthritis. This study aims to demonstrate the existence of ferroptosis in osteoarthritis and explore the specific mechanism of melatonin in suppressing ferroptosis and alleviating osteoarthritis. Our findings reveal that melatonin reverses inflammation-induced oxidative stress and lipid peroxidation while promoting the expression of extracellular matrix components in chondrocytes, safeguarding the cells. Our research has revealed that NADPH oxidase 4 (NOX4) serves as a crucial molecule in the ferroptosis process of osteoarthritis. Specifically, NOX4 is located on mitochondria in chondrocytes, which can induce disorders in mitochondrial energy metabolism and dysfunction, thereby intensifying oxidative stress and lipid peroxidation. LC-MS analysis further uncovered that GRP78 is a downstream binding protein of NOX4. NOX4 induces ferroptosis by weakening GRP78's protective effect on GPX4 and reducing its expression. Melatonin can inhibit the upregulation of NOX4 on mitochondria and mitigate mitochondrial dysfunction, effectively suppressing ferroptosis and alleviating osteoarthritis. This suggests that melatonin therapy represents a promising new approach for the treatment of osteoarthritis.

Research progress on GPX4 targeted compounds

Blocking the System Xc-_ GSH_GPX4 pathway to induce ferroptosis in tumor cells is a novel strategy for cancer treatment. GPX4 serves as the core of the System Xc-/GSH/GPX4 pathway and is a predominant target for inducing ferroptosis in tumor cells. This article summarizes compounds identified in current research that directly target the GPX4 protein, including inhibitors, activators, small molecule degraders, chimeric degraders, and the application of combination therapies with other drugs, aiming to promote further research on the target and related diseases.

Tannic acid as a biphasic modulator of tau protein liquid-liquid phase separation

Tannic acid (TA) is a natural polyphenol that shows great potential in the field of biomedicine due to its anti-inflammatory, anti-oxidant, anti-bacterial, anti-tumor, anti-virus, and neuroprotective activities. Recent studies have revealed that liquid-liquid phase separation (LLPS) is closely associated with protein aggregation. Therefore, modulating LLPS offers new insights into the treatment of neurodegenerative diseases. In this study, we investigated the influence of TA on the LLPS of the Alzheimer's-related protein tau and the underlying mechanism. Our findings indicate that TA affects the LLPS of tau in a biphasic manner, with initial promotion and subsequent suppression as the TA to tau molar ratio increases. TA modulates tau phase separation through a combination of hydrophobic interactions and hydrogen bonds. The balance between TA-tau and tau-tau interactions is found to be relevant to the material properties of TA-induced tau condensates. We further illustrate that the modulatory activity of TA in phase separation is highly dependent on the target proteins. These findings enhance our understanding of the forces driving tau LLPS under different conditions, and may facilitate the identification and optimization of compounds that can rationally modulate protein phase transition in the future.

Polycatechols inhibit ferroptosis and modulate tau liquid-liquid phase separation to mitigate Alzheimer's disease

Alzheimer's disease (AD) is a complex neurodegenerative disorder that affects learning, memory, and cognition. Current treatments targeting amyloid-β (Aβ) and tau have shown limited effectiveness, necessitating further research on the aggregation and toxicity mechanisms. One of these mechanisms involves the liquid-liquid phase separation (LLPS) of tau, contributing to the formation of pathogenic tau aggregates, although their conformational details remain elusive. Another mechanism is ferroptosis, a type of iron-dependent lipid peroxidation-mediated cell death, which has been implicated in AD. There is a lack of therapeutic strategies that simultaneously target amyloid toxicity and ferroptosis. This study aims to explore the potential of polycatechols, PDP and PLDP, consisting of dopamine and L-Dopa, respectively, as multifunctional agents to modulate the pathological nexus between ferroptosis and AD. Polycatechols were found to sequester the labile iron pool (LIP), inhibit Aβ and tau aggregation, scavenge free radicals, protect mitochondria, and prevent ferroptosis, thereby rescuing neuronal cell death. Interestingly, PLDP promotes tau LLPS, and modulates their intermolecular interactions to inhibit the formation of toxic tau aggregates, offering a conceptually innovative approach to tackle tauopathies. This is a first-of-its-kind polymer-based integrative approach that inhibits ferroptosis, counteracts amyloid toxicity, and modulates tau LLPS to mitigate the multifaceted toxicity of AD.

Recent Advances in the Inhibition of Membrane Lipid Peroxidation by Food-Borne Plant Polyphenols via the Nrf2/GPx4 Pathway

Lipid peroxidation (LP) leads to changes in the fluidity and permeability of cell membranes, affecting normal cellular function and potentially triggering apoptosis or necrosis. This process is closely correlated with the onset of many diseases. Evidence suggests that the phenolic hydroxyl groups in food-borne plant polyphenols (FPPs) make them effective antioxidants capable of preventing diseases triggered by cell membrane LP. Proper dietary intake of FPPs can attenuate cellular oxidative stress, especially damage to cell membrane phospholipids, by activating the Nrf2/GPx4 pathway. Nuclear factor E2-related factor 2 (Nrf2) is an oxidative stress antagonist. The signaling pathway regulated by Nrf2 is a defense transduction pathway of the organism against external stimuli such as reactive oxygen species and exogenous chemicals. Glutathione peroxidase 4 (GPx4), under the regulation of Nrf2, is the only enzyme that reduces cell membrane lipid peroxides with specificity, thus playing a pivotal role in regulating cellular ferroptosis and counteracting oxidative stress. This study explored the Nrf2/GPx4 pathway mechanism, antioxidant activity of FPPs, and mechanism of LP. It also highlighted the bioprotective properties of FPPs against LP and its associated mechanisms, including (i) activation of the Nrf2/GPx4 pathway, with GPx4 potentially serving as a central target protein, (ii) regulation of antioxidant enzyme activities, leading to a reduction in the production of ROS and other peroxides, and (iii) antioxidant effects on LP and downstream phospholipid structure. In conclusion, FPPs play a crucial role as natural antioxidants in preventing LP. However, further in-depth analysis of FPPs coregulation of multiple signaling pathways is required, and the combined effects of these mechanisms need further evaluation in experimental models. Human trials could provide valuable insights into new directions for research and application.

Multifunctional Nanocarrier for Synergistic Treatment of Alzheimer's Disease by Inhibiting β-Amyloid Aggregation and Scavenging Reactive Oxygen Species

The excessive depositions of β-amyloid (Aβ) and abnormal level of reactive oxygen species (ROS) are considered as the important pathogenic factors of Alzheimer's disease (AD). Strategies targeting only one of them have no obvious effects in clinic. In this study, a multifunctional nanocarrier CICe@M-K that crosses the blood-brain barrier (BBB) efficiently was developed for inhibiting Aβ aggregation and scavenging ROS synchronously. Antioxidant curcumin (Cur) and photosensitizer IR780 were loaded in mesoporous silica nanomaterials (MSNs). Their surfaces were grafted with cerium oxide nanoparticles (CeO2 NPs) and a short peptide K (CKLVFFAED). Living imaging showed that CICe@M-K was mainly distributed in the brain, liver, and kidneys, indicating CICe@M-K crossed BBB efficiently and accumulated in brain. After the irradiation of 808 nm laser, Cur was continuously released. Both of Cur and the peptide K can recognize and bind to Aβ through multiple interaction including π-π stacking interaction, hydrophobic interaction, and hydrogen bond, inhibiting Aβ aggregation. On the other hand, Cur and CeO2 NPs cooperate to relieve the oxidative stress in the brains by scavenging ROS. In vivo assays showed that the CICe@M-K could diminish Aβ depositions, alleviate oxidative stress, and improve cognitive ability of the APP/PS1 AD mouse model, which demonstrated that CICe@M-K is a potential agent for AD treatment.

Water extract of moschus alleviates erastin-induced ferroptosis by regulating the Keap1/Nrf2 pathway in HT22 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Moschus, first described in the Shennong's Classic of the Materia medicine, is a scarce and precious animal medicine. Modern pharmacological researches have suggested that Moschus has neuroprotective actions, and its mechanism is related to anti-inflammatory, antioxidant, and anti-apoptosis effects. Ferroptosis is one of the major pathologies of Alzheimer's disease (AD) and is widely implicated in the pathogenesis and progression of AD. Although previous studies have suggested that Moschus possesses neuroprotective effect, whether Moschus could mitigate neuronal damages by inhibiting the onset of ferroptosis is unknown in model cells of AD.

AIM OF THE STUDY

The aim of study was to explore the water extract of Moschus (WEM) on ferroptosis caused by erastin and the potential mechanism.

MATERIALS AND METHODS

Erastin was used to stimulate HT22 cells to form ferroptosis model to evaluate the anti-ferroptosis effect of WEM by cell counting kit-8 and lactic dehydrogenase (LDH) tests. The malondialdehyde (MDA) and glutathione (GSH) kits are used for detection of MDA and GSH levels, and 2',7'-dichlorofluorescein diacetate and C11 BODIPY 581/591 fluorescence probe are used for evaluation of reactive oxygen species (ROS) and lipid peroxide (LOOH) levels. And Western blot was used to test nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), heme oxygenase-1 (HO-1), and ferroptosis associated proteins including glutathione peroxidase 4 (GPX4), cystine/glutamate antiporter subunit (SLC7A11), ferritin heavy chain 1 (FTH1), ferroportin1 (FPN1), transferrin receptor (TFRC). In addition, the Nrf2 inhibitor ML385 was applied to verify whether WEM prevents erastin-induced ferroptosis by activating the Keap1/Nrf2 pathway.

RESULTS

After WEM treatment, erastin-induced HT22 cell survival was significantly elevated, the accumulation of intracellular MDA, ROS, and LOOH were significantly reduced, the level of GSH and expressions of ferroptosis inhibitors GPX4 and SLC7A11 were significantly increased, and iron metabolism-related proteins TFRC, FPN1, and FTH1 were regulated. These effects of WEM are implemented by activating the Keap1/Nrf2 pathway.

CONCLUSIONS

This study demonstrated that WEM could perform neuroprotective effects by alleviating ferroptosis, verified that WEM treatment of AD can be mediated by the Keap1/Nrf2 pathway, and provided theoretical support for the application of WEM in the treatment of AD.

Light-Triggered Nanozymes Remodel the Tumor Hypoxic and Immunosuppressive Microenvironment for Ferroptosis-Enhanced Antitumor Immunity

Cancer immunotherapy holds significant promise for addressing diverse malignancies. Nevertheless, its efficacy remains constrained by the intricate tumor immunosuppressive microenvironment. Herein, a light-triggered nanozyme Fe-TCPP-R848-PEG (Fe-MOF-RP) was designed for remodeling the immunosuppressive microenvironment. The Fe-TCPP-MOFs were utilized not only as a core catalysis component against tumor destruction but also as a biocompatible delivery vector of an immunologic agonist, improving its long circulation and tumor enrichment. Concurrently, it catalyzes the decomposition of H2O2 within the tumor, yielding oxygen to augment photodynamic therapy. The induced ferroptosis, in synergy with photodynamic therapy, prompts the liberation of tumor-associated antigens from tumor cells inducing immunogenic cell death. Phototriggered on-demand release of R848 agonists stimulated the maturation of dendritic cells and reverted the tumor-promoting M2 phenotypes into adoptive M1 macrophages, which further reshaped the tumor immunosuppressive microenvironment. Notably, the nanozyme effectively restrains well-established tumors, such as B16F10 melanoma. Moreover, it demonstrates a distal tumor-inhibiting effect upon in situ light treatment. What is more, in a lung metastasis model, it elicits robust immune memory, conferring enduring protection against tumor rechallenge. Our study presents a straightforward and broadly applicable strategy for crafting nanozymes with the potential to effectively thwart cancer recurrence and metastasis.

Hybrid molecules synergistically mitigate ferroptosis and amyloid-associated toxicities in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the build-up of extracellular amyloid β (Aβ) plaques and intracellular neurofibrillary tangles (NFTs). Ferroptosis, an iron (Fe)-dependent form of cell death plays a significant role in the multifaceted AD pathogenesis through generation of reactive oxygen species (ROS), mitochondrial damage, lipid peroxidation, and reduction in glutathione peroxidase 4 (GPX4) enzyme activity and levels. Aberrant liquid-liquid phase separation (LLPS) of tau drives the growth and maturation of NFTs contributing to AD pathogenesis. In this study, we strategically combined the structural and functional properties of gallic acid (GA) and cyclic dipeptides (CDPs) to synthesize hybrid molecules that effectively target both ferroptosis and amyloid toxicity in AD. This innovative approach marks a paradigm shift from conventional therapeutic strategies. This is the first report of a synthetic small molecule (GCTR) that effectively combats ferroptosis, simultaneously restoring enzymatic activity and enhancing cellular levels of its master regulator, GPX4. Further, GCTR disrupts Fe3+-induced LLPS of tau, and aids in attenuation of abnormal tau fibrillization. The synergistic action of GCTR in combating both ferroptosis and amyloid toxicity, bolstered by GPX4 enhancement and modulation of Fe3+-induced tau LLPS, holds promise for the development of small molecule-based novel therapeutics for AD.

Biphasic modulation of tau liquid-liquid phase separation by polyphenols

Molecular tools that modulate tau liquid-liquid phase separation (LLPS) promise to treat tauopathies. We screened a set of polyphenols and demonstrated concentration-dependent biphasic modulation of tau LLPS by gallic acid (GA), showcasing its ability to expedite the liquid-to-gel transition in tau condensates and effectively impede the formation of deleterious fibrillar aggregates.

PPT1 Promotes Growth and Inhibits Ferroptosis of Oral Squamous Cell Carcinoma Cells

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers with poor prognosis in the head and neck. Elucidating molecular mechanisms underlying OSCC occurrence and development is important for the therapy. Dysregulated palmitoylation-related enzymes have been reported in several cancers but OSCC.

OBJECTIVES

To explore the role of palmitoyl-protein thioesterase 1 (PPT1) in OSCC.

METHODS

Differentially expressed genes (DEGs) and related protein-protein interaction networks between normal oral epithelial and OSCC tissues were screened and constructed via different online databases. Tumor samples from 70 OSCC patients were evaluated for the relationship between PPT1 expression level and patients'clinic characteristics. The role of PPT1 in OSCC proliferation and metastasis was studied by functional experiments including MTT, colony formation, EdU incorporation and transwell assays. Lentivirus-based constructs were used to manipulate gene expression. FerroOrange probe and malondialdehyde assay were used to determine ferroptosis. Growth of OSCC cells in vivo was investigated by a xenograft mouse model.

RESULTS

A total of 555 DEGs were obtained, and topological analysis revealed that PPT1 and GPX4 might play critical roles in OSCC. Increased PPT1 expression was found to be correlated with poor prognosis of OSCC patients. PPT1 effectively promoted the proliferation, migration and invasion while inhibited the ferroptosis of OSCC cells. PPT1 affected the expression of glutathione peroxidase 4 (GPX4).

CONCLUSION

PPT1 promoted growth and inhibited ferroptosis of OSCC cells. PPT1 might be a potential target for OSCC therapy.

Oxygen metabolism abnormality and Alzheimer's disease: An update

Oxygen metabolism abnormality plays a crucial role in the pathogenesis of Alzheimer's disease (AD) via several mechanisms, including hypoxia, oxidative stress, and mitochondrial dysfunction. Hypoxia condition usually results from living in a high-altitude habitat, cardiovascular and cerebrovascular diseases, and chronic obstructive sleep apnea. Chronic hypoxia has been identified as a significant risk factor for AD, showing an aggravation of various pathological components of AD, such as amyloid β-protein (Aβ) metabolism, tau phosphorylation, mitochondrial dysfunction, and neuroinflammation. It is known that hypoxia and excessive hyperoxia can both result in oxidative stress and mitochondrial dysfunction. Oxidative stress and mitochondrial dysfunction can increase Aβ and tau phosphorylation, and Aβ and tau proteins can lead to redox imbalance, thus forming a vicious cycle and exacerbating AD pathology. Hyperbaric oxygen therapy (HBOT) is a non-invasive intervention known for its capacity to significantly enhance cerebral oxygenation levels, which can significantly attenuate Aβ aggregation, tau phosphorylation, and neuroinflammation. However, further investigation is imperative to determine the optimal oxygen pressure, duration of exposure, and frequency of HBOT sessions. In this review, we explore the prospects of oxygen metabolism in AD, with the aim of enhancing our understanding of the underlying molecular mechanisms in AD. Current research aimed at attenuating abnormalities in oxygen metabolism holds promise for providing novel therapeutic approaches for AD.