NOX4 promotes ferroptosis of astrocytes by oxidative stress-induced lipid peroxidation via the impairment of mitochondrial metabolism in Alzheimer's diseases

Mechanisms of ferroptosis in Alzheimer's disease and therapeutic effects of natural plant products: A review

Neurodegenerative diseases, such as Alzheimer's disease (AD), are characterized by massive loss of specific neurons. It is a progressive disabling, severe and fatal complex disease. Due to its complex pathogenesis and limitations of clinical treatment strategies, it poses a serious medical challenge and medical burden worldwide. The pathogenesis of AD is not clear, and its potential biological mechanisms include aggregation of soluble amyloid to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFT), neuroinflammation, ferroptosis, oxidative stress and metal ion disorders. Among them, ferroptosis is a newly discovered programmed cell death induced by iron-dependent lipid peroxidation and reactive oxygen species. Recent studies have shown that ferroptosis is closely related to AD, but the mechanism remains unclear. It may be induced by iron metabolism, amino acid metabolism and lipid metabolism affecting the accumulation of iron ions. Some iron chelating agents (deferoxamine, deferiprone), chloroiodohydroxyquine and its derivatives, antioxidants (vitamin E, lipoic acid, selenium), chloroiodohydroxyquine and its derivatives Fer-1, tet, etc. have been shown in animal studies to be effective in AD and exert neuroprotective effects. This review summarizes the mechanism of ferroptosis in AD and the regulation of natural plant products on ferroptosis in AD, in order to provide reference information for future research on the development of ferroptosis inhibitors.

A Concise Review on Oxidative Stress-Mediated Ferroptosis and Cuproptosis in Alzheimer's Disease

Alzheimer's disease (AD), which was first identified more than a century ago, has become a pandemic that exacts enormous social burden and economic tolls as no measure of combating devastated AD is currently available. Growing etiopathological, genetic, and biochemical data indicate that AD is a heterogeneous, polygenic, multifactorial, and complex disease. However, its exact etiopathology remains to be determined. Numerous experimental data show that cerebral iron and copper dyshomeostasis contribute to Aβ amyloidosis and tauopathy, two neuropathological hallmarks of AD. Moreover, increasing experimental evidence suggests ferroptosis, an iron-dependent and nonapoptotic form of cell death, may be involved in the neurodegenerative process in the AD brain. Thus, the anti-ferroptosis approach may be an efficacious therapeutic strategy for AD patients. Furthermore, it remains to be further determined whether cuproptosis, a copper-dependent and distinct form of regulated cell death, also plays a contributing role in AD neurodegeneration. We hope this concise review of recent experimental studies of oxidative stress-mediated ferroptosis and cuproptosis in AD may spur further investigations on this timely and essential line of research.

NOX4 is a potential therapeutic target in septic acute kidney injury by inhibiting mitochondrial dysfunction and inflammation

Rationale: Sepsis is a severe clinical syndrome featured through organ dysfunction due to infection, while the accompanying acute kidney injury (AKI) is linked to significant incidence of morbidity as well as mortality. Recently, emerging evidence has revealed that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) is implicated in various renal diseases, while its role and modulation in septic acute kidney injury (S-AKI) remains largely unknown. Methods: In vivo, S-AKI in wild-type and renal tubular epithelial cell (RTEC)-specific NOX4 knockout mice was induced by lipopolysaccharides (LPS) injection or cecal ligation and puncture (CLP). In vitro, TCMK-1 (mouse kidney tubular epithelium cell line) cells were treated with LPS. Serum and supernatant biochemical, mitochondrial dysfunctional, inflammatory and apoptotic parameters were measured and compared across groups. The activation of reactive oxygen species (ROS) and NF-κB signaling was also assessed. Results: NOX4 was predominantly upregulated in RTECs of S-AKI mouse model induced by LPS/CLP and cultured TCMK-1 cells exposed to LPS. RTEC-specific deletion of NOX4 or pharmacological inhibition of NOX4 by GKT137831 both alleviated LPS/CLP-injured renal function and pathology in mice. Furthermore, NOX4 inhibition alleviated mitochondrial dysfunction supported by ultrastructural damage, reduction of ATP production and mitochondrial dynamics imbalance, together with inflammation and apoptosis in kidney injured by LPS/CLP and TCMK-1 cells injured by LPS, while NOX4 overexpression aggravated the above-mentioned indices in TCMK-1 cells with LPS stimulation. Mechanism-wise, the raised NOX4 in RTECs may induce ROS and NF-κB signaling activation in S-AKI. Conclusions: Collectively, genetic or pharmacological inhibition of NOX4 protects from S-AKI by reducing generation of ROS and activation of NF-κB signal, which suppress mitochondrial dysfunction, inflammation together with apoptosis. NOX4 may act as a novel target for the S-AKI therapy.

Maintenance of mitochondrial homeostasis for Alzheimer's disease: Strategies and challenges

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, and its early onset is closely related to mitochondrial energy metabolism. The brain is only 2% of body weight, but consumes 20% of total energy needs. Mitochondria are responsible for providing energy in cells, and maintaining their homeostasis ensures an adequate supply of energy to the brain. Mitochondrial homeostasis is constituted by mitochondrial quantity and quality control, which is dynamically regulated by mitochondrial energy metabolism, mitochondrial dynamics and mitochondrial quality control. Impaired energy metabolism of brain cells occurs early in AD, and maintaining mitochondrial homeostasis is a promising therapeutic target in the future. We summarized the mechanism of mitochondrial homeostasis in AD, its influence on the pathogenesis of early AD, strategies for maintaining mitochondrial homeostasis, and mitochondrial targeting strategies. This review concludes with the authors' opinions on future research and development for mitochondrial homeostasis of early AD.

TXNIP contributes to induction of pro-inflammatory phenotype and caspase-3 activation in astrocytes during Alzheimer's diseases

Neuroinflammation and oxidative stress have been implicated in the pathogenesis of Alzheimer's disease (AD). Neuroinflammation and oxidative stress are associated with neuronal death in AD. Astrocytes are linked to neuroinflammation during AD. Astrocytes are important contributors to AD progression. Although the role of thioredoxin-interacting protein (TXNIP) has been identified in inflammation and oxidative stress, the mechanism by which TXNIP regulates inflammation and oxidative stress in astrocytes during AD remains unclear. In the present study, we found that TXNIP gene levels were elevated in cerebral cortex of patients with AD. The protein levels of TXNIP were elevated in GFAP-positive astrocytes of cerebral cortex from patients with AD and APP/PS1 double-transgenic mouse model of AD. Our results showed that TXNIP increased expression of genes related to pro-inflammatory reactive astrocytes and pro-inflammatory cytokines and chemokines in human astrocytes. Moreover, TXNIP increased production of pro-inflammatory cytokines and chemokines in human astrocytes. TXNIP induced activation of NK-kB signaling and over-production of mitochondrial reactive oxygen species (mtROS) in human astrocytes. TXNIP also induced mitochondrial oxidative stress by reduction of mitochondrial respiration and ATP production in human astrocytes. Furthermore, elevated TXNIP levels are correlated with caspase-3 activation of GFAP-positive astrocytes in patients with AD and mouse AD. TXNIP induced mitochondria-dependent apoptosis via caspase-9 and caspase-3 activation in human astrocytes. These results suggest that TXNIP contributes to induction of pro-inflammatory phenotype and caspase-3 activation in astrocytes during AD.

Polydopamine Nanoparticles Targeting Ferroptosis Mitigate Intervertebral Disc Degeneration Via Reactive Oxygen Species Depletion, Iron Ions Chelation, and GPX4 Ubiquitination Suppression

Intervertebral disc degeneration (IVDD)-induced lower back pain (LBP) is a common problem worldwide. The underlying mechanism is partially accredited to ferroptosis, based on sequencing analyses of IVDD patients from the gene expression omnibus (GEO) databases. In this study, it is shown that polydopamine nanoparticles (PDA NPs) inhibit oxidative stress-induced ferroptosis in nucleus pulposus (NP) cells in vitro. PDA NPs scavenge reactive oxygen species (ROS), chelate Fe²⁺ to mitigate iron overload, and regulate the expression of iron storage proteins such as ferritin heavy chain (FHC), ferritin, and transferrin receptor (TFR). More importantly, PDA NPs co-localize with glutathione peroxidase 4 (GPX4) around the mitochondria and suppress ubiquitin-mediated degradation, which in turn exerts a protective function via the transformation and clearance of phospholipid hydroperoxides. PDA NPs further down-regulate malondialdehyde (MDA) and lipid peroxide (LPO) production; thus, antagonizing ferroptosis in NP cells. Moreover, PDA NPs effectively rescue puncture-induced degeneration in vivo by targeting ferroptosis and inhibiting GPX4 ubiquitination, resulting in the upregulation of antioxidant pathways. The findings offer a new tool to explore the underlying mechanisms and a novel treatment strategy for IVDD-induced LBP.

Zooming in and out of ferroptosis in human disease

Ferroptosis is defined as an iron-dependent regulated form of cell death driven by lipid peroxidation. In the past decade, it has been implicated in the pathogenesis of various diseases that together involve almost every organ of the body, including various cancers, neurodegenerative diseases, cardiovascular diseases, lung diseases, liver diseases, kidney diseases, endocrine metabolic diseases, iron-overload-related diseases, orthopedic diseases and autoimmune diseases. Understanding the underlying molecular mechanisms of ferroptosis and its regulatory pathways could provide additional strategies for the management of these disease conditions. Indeed, there are an expanding number of studies suggesting that ferroptosis serves as a bona-fide target for the prevention and treatment of these diseases in relevant pre-clinical models. In this review, we summarize the progress in the research into ferroptosis and its regulatory mechanisms in human disease, while providing evidence in support of ferroptosis as a target for the treatment of these diseases. We also discuss our perspectives on the future directions in the targeting of ferroptosis in human disease.

Gli1 depletion induces oxidative stress and apoptosis of nucleus pulposus cells via Fos in intervertebral disc degeneration

Background

Intervertebral disc degeneration (IDD) is the most common chronic disease. Oxidative stress and apoptosis of nucleus pulposus (NP) cells disrupt intervertebral disc (IVD) homeostasis, which is the main cause of IDD. Glioma-associated oncogene 1 (Gli1) is an important transcription factor in the Hedgehog (Hh) pathway. Depletion of Gli1 accelerates the occurrence and development of degenerative diseases. This study aimed to explore the role of aging related Gli1 depletion in the progression of IDD.

Methods

The relationship between aging related Gli1 depletion and IDD was studied in the NP tissues of human and rats of different ages, and the levels of oxidative stress and NP cell apoptosis during IDD were explored. Gli1 depletion of NP cells were established by targeting inhibitor GANT61 or lentivirus-coated Gli1 sh-RNA (sh-Gli1) to explore the role of Gli1 in NP cells and underlying mechanism. Exogenous Gli1 depletion induced IDD of rats was established by intraperitoneal injection of GANT61. Also, the roles of Fos in the Gli1 depletion induced NP cell oxidative stress, apoptosis and IDD were investigated.

Results

Gli1 was down-regulated in the tissues of degenerative NP, and the level of Gli1 was negatively correlated with the severity of aging related IDD in human and rats. Furthermore, we found enhanced oxidative stress and apoptosis in degenerative NP tissues. Gli1 depletion promoted oxidative stress and apoptosis of NP cells and resulted in the degradation of extracellular matrix (ECM) and decreased ECM synthesis. Transcriptome sequencing showed that Gli1 depletion caused Fos activation in NP cells. the effect of Gli1 depletion on the oxidative stress and apoptosis of NP cells were retarded by Fos inhibitor. In vivo, Fos inhibition alleviated the IDD induced by exogenous Gli1 depletion.

Conclusions

This study revealed for the first time that Gli1 is gradually depleted in NP with IDD progression. Exogenous Gli1 depletion causes oxidative stress and apoptosis of NP cells both in vivo and in vitro. Fos suppression effectively retards the destructive effects of Gli1 depletion on IVD homoeostasis.The translational potential of this article: This study may provide new potential targets for preventing and reversing IDD. Maintaining Gli1 expression in NP and suppressing Fos activation may be an effective treatment strategy for IDD.

ENPP2 alleviates hypoxia/reoxygenation injury and ferroptosis by regulating oxidative stress and mitochondrial function in human cardiac microvascular endothelial cells

This study aimed to elucidate the molecular mechanisms of hypoxia/reoxygenation (H/R) injury in human cardiac microvascular endothelial cells (HCMECs) by regulating ferroptosis. H/R model was established with HCMECs and before the reperfusion, ferroptosis inhibitor ferrostatin-1 or ferroptosis inducer erastin was all administered. Wound-healing assay was performed to detect the migration ability of cells in each group, and the angiogenesis ability was determined by tube formation assay. The level of reactive oxygen species (ROS) was detected by flow cytometry. Transmission electron microscopy (TEM) was used to observe the state of mitochondria. The expressions of related proteins in HCMECs were assessed by Western blot. From the results, H/R injury could inhibit the migration and angiogenesis, induce the ROS production, and cause the mitochondrial damage of HCMECs. Ferroptosis activator erastin could aggravate H/R injury in HCMECs, while the ferroptosis inhibitor ferrostatin-1 could reverse the effects of H/R on HCMECs. Western blot results showed that H/R or/and erastin treatment could significantly induce ACSL4, HGF, VEGF, p-ERK, and uPA protein expression and inhibit GPX4 expression. The addition of ferrostatin-1 resulted in the opposite trend of the proteins expression above to erastin treatment. What is more, overexpression of ENPP2 markedly suppressed the damaging effect of H/R on HCMECs and reversed the effects of H/R or erastin treatment on the expression of related proteins. These results demonstrated a great therapeutic efficacy of ENPP2 overexpression in preventing the development of H/R injury through inhibiting oxidative stress and ferroptosis.

Intermittent fasting alleviates type 1 diabetes-induced cognitive dysfunction by improving the frontal cortical metabolic disorder

Intermittent fasting (IF) is an ecological strategy to control various metabolic disorder symptoms, but its protective effect on type 1 diabetes (T1D)-induced cognitive dysfunction and the underlying mechanisms remain poorly defined. Herein, we examined the efficacy of IF in altering the behaviors and brain metabolome in T1D mice and investigated the potential molecular mechanisms. We demonstrated that IF remarkably improved frontal cortical-dependent memory in T1D mice and reduced the loss of neuronal cells. Metabolomics and targeted mass spectrometry assay showed that IF reprogrammed the frontal cortical metabolome composition, including activated the aspartate and glutamate pathway and reversed glycerophospholipid and sphingolipid depositions in T1D mice. Mechanistically, IF attenuated the levels of oxidative stress proteins, such as NOX2, NOX4, 8-OHdG, 4-HNE, and inhibited the levels of pro-apoptotic factors Bax and cleaved Caspase-3, finally improved the memory ability of T1D mice. In vitro studies confirmed the protective effect of the supplemented N-acetylaspartate, a pivotal metabolite involved in IF-regulated T1D-induced cognitive dysfunction, in high glucose-stimulated SH-SY5Y cells by eliminating toxic lipids accumulation, oxidative stress and apoptosis. To conclude, the frontal cortical metabolites mediated the protective effects of IF against T1D-induced cognitive dysfunction by attenuating oxidative stress and apoptotic signaling. Thus, IF can be a potential therapeutic strategy for T1D-induced cognitive dysfunction.

TRIM-containing 44 aggravates cardiac hypertrophy via TLR4/NOX4-induced ferroptosis

TRIM-containing 44 (TRIM44) is a promoter of multiple cancers. However, its role in cardiac hypertrophy has not been elucidated. This study explored the role of TRIM44 on pressure overload-induced cardiac hypertrophy in mice. Mice were subjected to aortic banding to establish an adverse cardiac hypertrophy model, followed by the administration of AAV9-TRIM44 or AAV9shTRIM44 to overexpress or knock down TRIM44. Echocardiography was used to assess cardiac function. H9c2 cells were cultured and transfected with either Ad-TRIM44 or TRIM44 siRNA to overexpress or silence TRIM44. Cells were also stimulated with angiotensin II to establish a cardiomyocyte hypertrophy model. Results indicated that TRIM44 was downregulated in mice hearts and cardiomyocytes that were treated with aortic banding or angiotensin II. TRIM44 overexpression in mice hearts aggravated cardiac hypertrophy and fibrosis, as well as inhibited cardiac function post-aortic banding. Moreover, mice with TRIM44 overexpression displayed increased ferroptosis post-aortic banding. Mice with TRIM44 knockdown revealed ameliorated cardiac hypertrophy, ferroptosis, and fibrosis, as well as improved cardiac function post-aortic banding. In H9c2 cells transfected with Ad-TRIM44, angiotensin II-induced ferroptosis was enhanced, while cells with silenced TRIM44 reported reduced ferroptosis post-angiotensin II administration. Furthermore, TRIM44 interacted with TLR4, which increased the expression of NOX4 and subsequently augmented ferroptosis-associated protein levels. By using TLR4 knockout mice, the inhibitory role of TRIM44 was reduced post-aortic banding. Taken together, TRIM44 aggravated pressure overload-induced cardiac hypertrophy via increased TLR4/NOX4-associated ferroptosis. KEY MESSAGES: TRIM44 could aggregate pressure overload-induced cardiac hypertrophy via increasing TLR4-NOX4 associated ferroptosis. Target TRIM44 may become a new therapeutic method for preventing or treating pressure overload-induced cardiac hypertrophy.

Revisiting the intersection of microglial activation and neuroinflammation in Alzheimer's disease from the perspective of ferroptosis

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by chronic neuroinflammation with amyloid beta-protein deposition and hyperphosphorylated tau protein. The typical clinical manifestation of AD is progressive memory impairment, and AD is considered a multifactorial disease with various etiologies (genetic factors, aging, lifestyle, etc.) and complicated pathophysiological processes. Previous research identified that neuroinflammation and typical microglial activation are significant mechanisms underlying AD, resulting in dysfunction of the nervous system and progression of the disease. Ferroptosis is a novel modality involved in this process. As an iron-dependent form of cell death, ferroptosis, characterized by iron accumulation, lipid peroxidation, and irreversible plasma membrane disruption, promotes AD by accelerating neuronal dysfunction and abnormal microglial activation. In this case, disturbances in brain iron homeostasis and neuronal ferroptosis aggravate neuroinflammation and lead to the abnormal activation of microglia. Abnormally activated microglia release various pro-inflammatory factors that aggravate the dysregulation of iron homeostasis and neuroinflammation, forming a vicious cycle. In this review, we first introduce ferroptosis, microglia, AD, and their relationship. Second, we discuss the nonnegligible role of ferroptosis in the abnormal microglial activation involved in the chronic neuroinflammation of AD to provide new ideas for the identification of potential therapeutic targets for AD.

Cntnap4 partial deficiency exacerbates α-synuclein pathology through astrocyte-microglia C3-C3aR pathway

Parkinson's disease (PD) is the most common progressive neurodegenerative movement disorder, which is characterized by dopaminergic (DA) neuron death and the aggregation of neurotoxic α-synuclein. Cntnap4, a risk gene of autism, has been implicated to participate in PD pathogenesis. Here we showed Cntnap4 lacking exacerbates α-synuclein pathology, nigrostriatal DA neuron degeneration and motor impairment, induced by injection of adeno-associated viral vector (AAV)-mediated human α-synuclein overexpression (AAV-hα-Syn). This scenario was further validated in A53T α-synuclein transgenic mice injected with AAV-Cntnap4 shRNA. Mechanistically, α-synuclein derived from damaged DA neuron stimulates astrocytes to release complement C3, activating microglial C3a receptor (C3aR), which in turn triggers microglia to secrete complement C1q and pro-inflammatory cytokines. Thus, the astrocyte-microglia crosstalk further drives DA neuron death and motor dysfunction in PD. Furthermore, we showed that in vivo depletion of microglia and microglial targeted delivery of a novel C3aR antagonist (SB290157) rescue the aggravated α-synuclein pathology resulting from Cntnap4 lacking. Together, our results indicate that Cntnap4 plays a key role in α-synuclein pathogenesis by regulating glial crosstalk and may be a potential target for PD treatment.

The deubiquitinase USP11 ameliorates intervertebral disc degeneration by regulating oxidative stress-induced ferroptosis via deubiquitinating and stabilizing Sirt3

Increasing studies have reported that intervertebral disc degeneration (IVDD) is the main contributor and independent risk factor for low back pain (LBP), it would be, therefore, enlightening that investigating the exact pathogenesis of IVDD and developing target-specific molecular drugs in the future. Ferroptosis is a new form of programmed cell death characterized by glutathione (GSH) depletion, and inactivation of the regulatory core of the antioxidant system (glutathione system) GPX4. The close relationship of oxidative stress and ferroptosis has been studied in various of diseases, but the crosstalk between of oxidative stress and ferroptosis has not been explored in IVDD. At the beginning of the current study, we proved that Sirt3 decreases and ferroptosis occurs after IVDD. Next, we found that knockout of Sirt3 (Sirt3^-/-) promoted IVDD and poor pain-related behavioral scores via increasing oxidative stress-induced ferroptosis. The (immunoprecipitation coupled with mass spectrometry) IP/MS and co-IP demonstrated that USP11 was identified to stabilize Sirt3 via directly binding to Sirt3 and deubiquitinating Sirt3. Overexpression of USP11 significantly ameliorate oxidative stress-induced ferroptosis, thus relieving IVDD by increasing Sirt3. Moreover, knockout of USP11 in vivo (USP11^-/-) resulted in exacerbated IVDD and poor pain-related behavioral scores, which could be reversed by overexpression of Sirt3 in intervertebral disc. In conclusion, the current study emphasized the importance of the interaction of USP11 and Sirt3 in the pathological process of IVDD via regulating oxidative stress-induced ferroptosis, and USP11-mediated oxidative stress-induced ferroptosis is identified as a promising target for treating IVDD.

NOX4 as a critical effector mediating neuroinflammatory cytokines, myeloperoxidase and osteopontin, specifically in astrocytes in the hippocampus in Parkinson's disease

Oxidative stress and mitochondrial dysfunction have been believed to play an important role in the pathogenesis of aging and neurodegenerative diseases, including Parkinson's disease (PD). The excess of reactive oxygen species (ROS) increases with age and causes a redox imbalance, which contributes to the neurotoxicity of PD. Accumulating evidence suggests that NADPH oxidase (NOX)-derived ROS, especially NOX4, belong to the NOX family and is one of the major isoforms expressed in the central nervous system (CNS), associated with the progression of PD. We have previously shown that NOX4 activation regulates ferroptosis via astrocytic mitochondrial dysfunction. We have previously shown that activation of NOX4 regulates ferroptosis through mitochondrial dysfunction in astrocytes. However, it remains unclear why an increase in NOX4 in neurodegenerative diseases leads to astrocyte cell death by certain mediators. Therefore, this study was designed to evaluate how NOX4 in the hippocampus is involved in PD by comparing an MPTP-induced PD mouse model compared to human PD patients. We could detect that the hippocampus was dominantly associated with elevated levels of NOX4 and α-synuclein during PD and the neuroinflammatory cytokines, myeloperoxidase (MPO) and osteopontin (OPN), were upregulated particularly in astrocytes. Intriguingly, NOX4 suggested a direct intercorrelation with MPO and OPN in the hippocampus. Upregulation of MPO and OPN induces mitochondrial dysfunction by suppressing five protein complexes in the mitochondrial electron transport system (ETC) and increases the level of 4-HNE leading to ferroptosis in human astrocytes. Overall, our findings indicate that the elevation of NOX4 cooperated with the MPO and OPN inflammatory cytokines through mitochondrial aberration in hippocampal astrocytes during PD.

Natural Flavonoids and Ferroptosis: Potential Therapeutic Opportunities for Human Diseases

Flavonoids are a class of bioactive phytochemicals containing a core 2-phenylchromone skeleton and are widely found in fruits, vegetables, and herbs. Such natural compounds have gained significant attention due to their various health benefits. Ferroptosis is a recently discovered unique iron-dependent mode of cell death. Unlike traditional regulated cell death (RCD), ferroptosis is associated with excessive lipid peroxidation on cellular membranes. Accumulating evidence suggests that this form of RCD is involved in a variety of physiological and pathological processes. Notably, multiple flavonoids have been shown to be effective in preventing and treating diverse human diseases by regulating ferroptosis. In this review, we introduce the key molecular mechanisms of ferroptosis, including iron metabolism, lipid metabolism, and several major antioxidant systems. Additionally, we summarize the promising flavonoids targeting ferroptosis, which provides novel ideas for the management of diseases such as cancer, acute liver injury, neurodegenerative diseases, and ischemia/reperfusion (I/R) injury.

Nox4-and Tf/TfR-mediated peroxidation and iron overload exacerbate neuronal ferroptosis after intracerebral hemorrhage: Involvement of EAAT3 dysfunction

Intracerebral hemorrhage (ICH) induces high mortality and disability. Neuronal death is the principal factor to unfavourable prognosis in ICH. However, the mechanisms underlying this association remain unclear. In this study, we investigated the molecular mechanisms by which neuronal ferroptosis occurs after ICH and whether the use of corresponding modulators can inhibit neuronal death and improve early outcomes in a rat ICH model. Our findings indicated that Nox4 and TF/TfR were upregulated in the perihematomal tissues of ICH rats. Oxidative stress and iron overload induced by Nox4 and TF/TfR promoted neuronal ferroptosis post-ICH. In contrast, application of Nox4-siRNA and the deferoxamine (DFO) attenuated peroxidation and iron deposition in the hemorrhagic brain, alleviated neuronal ferroptosis, and improved sensorimotor function in ICH rats. Additionally, our findings indicated that the post-ICH neuronal reduced glutathione (GSH) depletion were not related to dysfunctional glutamine delivery in astrocytes but rather to downregulation of EAAT3 due to lipid peroxidation-induced dysfunction in the neuronal membrane. These findings indicate that ferroptosis is involved in neuronal death in model rats with collagenase-induced ICH. Oxidative stress and iron overload induced by Nox4 and TF/TfR exacerbate ferroptosis after ICH, while Nox4 downregulation and iron chelation exert neuroprotective effects. The present results highlight the cysteine importer EAAT3 as a potential biomarker of ferroptosis and provide insight into the neuronal death process that occurs following ICH, which may aid in the development of translational treatment strategies for ICH.

ChREBP-β/TXNIP aggravates frucose-induced renal injury through triggering ferroptosis of renal tubular epithelial cells

High fructose intake is an essential risk factor for kidney injury. However, the specific mechanism underlying high fructose-induced kidney injury remains unclarified. Carbohydrate response element-binding protein (ChREBP) is a key transcriptional activator that regulates fructose metabolism. ChREBP-β exhibits sustained activity due to the lack of a low glucose inhibitory domain, and is thus described as the active form of ChREBP. In this study, a mouse model with specific overexpression of ChREBP-β in the renal tubule was established by using the Cre/LoxP method. Quantitative proteomic analysis and experimental verification results suggest that ChREP-β overexpression leads to ferroptosis of renal tubular epithelial cells and kidney injury. ChREPB-β promotes the gene transcription of thioredoxin-interacting protein (TXNIP) and thereby increases its expression level. TXNIP is associated with activation of ferroptosis. TXNIP can initiate ferroptosis and eventually contribute to high fructose-induced renal tubular epithelial cell damage. Through down-regulating ChREBP-β, metformin can inhibit gene transcription of TXNIP, attenuate high fructose-induced ferroptosis in renal tubular epithelial cells, and alleviate kidney injury. In conclusion, ChREBP-β mediates fructose-induced ferroptosis of renal tubular epithelial cells, and metformin with a ChREBP-β inhibitory effect may be a potential treatment for ferroptosis of renal tubular epithelial cells.

TRPM2 Channel Inhibition Attenuates Amyloid β42-Induced Apoptosis and Oxidative Stress in the Hippocampus of Mice

Alzheimer's disease (AD) is characterized by the increase of hippocampal Ca²⁺ influx-induced apoptosis and mitochondrial oxidative stress (OS). The OS is a stimulator of TRPM2, although N-(p-amylcinnamoyl)anthranilic acid (ACA), 2-aminoethyl diphenylborinate (2/APB), and glutathione (GSH) are non-specific antagonists of TRPM2. In the present study, we investigated the protective roles of GSH and TRPM2 antagonist treatments on the amyloid β42 peptide (Aβ)-caused oxidative neurotoxicity and apoptosis in the hippocampus of mice with AD model. After the isolation of hippocampal neurons from the newborn mice, they were divided into five incubation groups as follows: control, ACA, Aβ, Aβ+ACA, and Aβ+GSH. The levels of apoptosis, hippocampus death, cytosolic ROS, cytosolic Zn²⁺, mitochondrial ROS, caspase-3, caspase-9, lipid peroxidation, and cytosolic Ca²⁺ were increased in the primary hippocampus cultures by treatments of Aβ, although their levels were decreased in the neurons by the treatments of GSH, PARP-1 inhibitors (PJ34 and DPQ), and TRPM2 blockers (ACA and 2/APB). The Aβ-induced decreases of cell viability, cytosolic GSH, reduced GSH, and GSH peroxidase levels were also increased in the groups of Aβ+ACA and Aβ+GSH by the treatments of ACA and GSH. However, the Aβ-caused changes were not observed in the hippocampus of TRPM2-knockout mice. In conclusion, the present data demonstrate that maintaining the activation of TRPM2 is not only important for the quenching OS and neurotoxicity in the hippocampal neurons of mice with experimental AD but also equally critical to the modulation of Aβ-induced apoptosis. The possible positive effects of GSH and TRPM2 antagonist treatments on the amyloid-beta (Aβ)-induced oxidative toxicity in the hippocampus of mice. The ADP-ribose (ADPR) is produced via the stimulation of PARP-1 in the nucleus of neurons. The NUT9 in the C terminus of TRPM2 channel acts as a key role for the activation of TRPM2. The antagonists of TRPM2 are glutathione (GSH), ACA, and 2/APB in the hippocampus. The Aβ incubation-mediated TRPM2 stimulation increases the concentration of cytosolic-free Ca²⁺ and Zn²⁺ in the hippocampus. In turn, the increased concentration causes the increase of mitochondrial membrane potential (ΔΨm), which causes the excessive generations of mitochondria ROS and the decrease of cytosolic GSH and GSH peroxidase (GSH-Px). The ROS production and GSH depletion are two main causes in the neurobiology of Alzheimer's disease. However, the effect of Aβ was not shown in the hippocampus of TRPM2-knockout mice. The Aβ and TRPM2 stimulation-caused overload Ca²⁺ entry cause apoptosis and cell death via the activations of caspase-3 (Casp/3) and caspase-9 (Casp/9) in the hippocampus. The actions of Aβ-induced oxidative toxicity were modulated in the primary hippocampus by the incubations of ACA, GSH, 2/APB, and PARP-1 inhibitors (PJ34 and DPQ). (↑) Increase. (↓) Decrease.

Nutrient sensing signaling and metabolic responses in shrimp Litopenaeus vannamei under acute ammonia stress

Ammonia is the primary environmental factor affecting the growth and health of crustaceans. It would induce oxidative stress and metabolic disorders. Extra amount of energy was demanded to maintain the physiological functions under ammonia stress. However, limited information was available on its effects on the main nutrient metabolism, as well as the nutrient sensing signaling pathways. In the present study, shrimp Litopenaeus vannamei were exposed to acute ammonia stress and injected with amino acid solution. The results showed that acute ammonia exposure resulted in lower free amino acid levels in hemolymph, incomplete activation of the mechanistic target of rapamycin (mTOR) signaling and cascaded less protein synthesis in muscle. It induced autophagy and activated the AMP-activated protein kinase (AMPK) pathway. Meanwhile, ammonia exposure enhanced glycolysis and lipogenesis, but inhibited lipolysis. The results characterized the integrated metabolic responses and nutrient signaling to ammonia stress. It provides critical clues to understand the growth performance and physiological responses in shrimp under ammonia stress.

Levosimendan Reverses Cardiac Malfunction and Cardiomyocyte Ferroptosis During Heart Failure with Preserved Ejection Fraction via Connexin 43 Signaling Activation

PURPOSE

In recent decades, the occurrence of heart failure with preserved ejection fraction (HFpEF) has outweighed that of heart failure with reduced ejection fraction by degrees, but few drugs have been demonstrated to improve long-term clinical outcomes in patients with HFpEF. Levosimendan, a calcium-sensitizing cardiotonic agent, improves decompensated heart failure clinically. However, the anti-HFpEF activities of levosimendan and underlying molecular mechanisms are unclear.

METHODS

In this study, a double-hit HFpEF C57BL/6N mouse model was established, and levosimendan (3 mg/kg/week) was administered to HFpEF mice aged 13 to 17 weeks. Different biological experimental techniques were used to verify the protective effects of levosimendan against HFpEF.

RESULTS

After four weeks of drug treatment, left ventricular diastolic dysfunction, cardiac hypertrophy, pulmonary congestion, and exercise exhaustion were significantly alleviated. Junction proteins in the endothelial barrier and between cardiomyocytes were also improved by levosimendan. Among the gap junction channel proteins, connexin 43, which was especially highly expressed in cardiomyocytes, mediated mitochondrial protection. Furthermore, levosimendan reversed mitochondrial malfunction in HFpEF mice, as evidenced by increased mitofilin and decreased ROS, superoxide anion, NOX4, and cytochrome C levels. Interestingly, after levosimendan administration, myocardial tissue from HFpEF mice showed restricted ferroptosis, indicated by an increased GSH/GSSG ratio; upregulated GPX4, xCT, and FSP-1 expression; and reduced intracellular ferrous ion, MDA, and 4-HNE levels.

CONCLUSION

Regular long-term levosimendan administration can benefit cardiac function in a mouse model of HFpEF with metabolic syndromes (namely, obesity and hypertension) by activating connexin 43-mediated mitochondrial protection and sequential ferroptosis inhibition in cardiomyocytes.

The role of ferroptosis mediated by Bmal1/Nrf2 in nicotine -induce injury of BTB integrity

Nicotine has shown the toxic effects on male reproductive system, and testicular damage is associated with ferroptosis, which is a non-apoptotic regulated cell death driven by iron-dependent lipid peroxidation. However, the role of nicotine on ferroptosis of testicular cells is largely elusive. In the present study, we showed that nicotine destroyed blood-testis barrier (BTB) by interfering with the circadian rhythm of BTB-related factors (ZO-1, N-Cad, Occludin and CX-43) and induced ferroptosis, as reflected via increased clock-control levels of lipid peroxide and decreased ferritin and GPX4, which involved in the circadian. Inhibition of ferroptosis with Fer-1 alleviated nicotine-induced injury of BTB and impaired sperm in vivo. Mechanically, we uncover that the core molecular clock protein, Bmal1, regulates the expression of Nrf2 via direct E-box binding to its promoter to regulate its activity, and nicotine decreases the transcription of Nrf2 through Bmal1 and inactivates Nrf2 pathway and its downstream antioxidant gene, which leads to the imbalance of redox state and ROS accumulation. Intriguingly, nicotine induced lipid peroxidation and subsequent ferroptosis by Bmal1-mediated Nrf2. In conclusion, our study reveals a clear role for the molecular clock in controlling Nrf2 in testis to mediate the ferroptosis induced by nicotine. These findings provide a potential mechanism to prevent smoking and/or cigarette smoke-induced male reproductive injury.

Inhibition of ferroptosis through regulating neuronal calcium homeostasis: An emerging therapeutic target for Alzheimer's disease

Alzheimer's disease (AD), a chronic and progressive neurodegenerative disease, generates a serious threat to the health of the elderly. The AD brain is microscopically characterized by amyloid plaques and neurofibrillary tangles. There are still no effective therapeutic drugs to restrain the progression of AD though much attention has been paid to exploit AD treatments. Ferroptosis, a type of programmed cell death, has been reported to promote the pathological occurrence and development of AD, and inhibition of neuronal ferroptosis can effectively improve the cognitive impairment of AD. Studies have shown that calcium (Ca²⁺) dyshomeostasis is closely related to the pathology of AD, and can drive the occurrence of ferroptosis through several pathways, such as interacting with iron, and regulating the crosstalk between endoplasmic reticulum (ER) and mitochondria. This paper mainly reviews the roles of ferroptosis and Ca²⁺ in the pathology of AD, and highlights that restraining ferroptosis through maintaining the homeostasis of Ca²⁺ may be an innovative target for the treatment of AD.

Depleted uranium causes renal mitochondrial dysfunction through the ETHE1/Nrf2 pathway

The kidney is the main organ affected by acute depleted uranium (DU) toxicity. The mechanism of nephrotoxicity induced by DU is complex and needs to be further explored. This study aimed to elucidate the function of mitochondrial dysfunction in nephrotoxicity generated by DU and confirm the latent mechanism. We verified that DU (2.5-10 mg/kg) caused mitochondrial dysfunction in male rat kidneys and decreased ATP content and the mitochondrial membrane potential. In addition, melatonin (20 mg/kg), as an antioxidant, alleviated DU-induced oxidative stress and mitochondrial dysfunction in male rats, further reducing kidney damage caused by DU. These results indicate that mitochondrial dysfunction plays a vital role in DU nephrotoxicity. When ethylmalonic encephalopathy 1 (ETHE1) was knocked down, DU-induced oxidative stress and mitochondrial dysfunction were increased, and renal injury was aggravated. When exogenous ETHE1 protein was applied to renal cells, the opposite changes were observed. We also found that ETHE1 knockdown increased the expression of NF-E2-related factor 2 (Nrf2), a vital oxidative stress regulator, and its downstream molecules heme oxygenase-1 (HO-1) and NADPH quinone oxidoreductase 1 (NQO1). Nrf2 knockout also aggravated DU-induced oxidative stress, mitochondrial dysfunction, and kidney damage. In conclusion, DU causes oxidative stress and antioxidant defense imbalance in renal cells through the ETHE1/Nrf2 pathway, further causing mitochondrial dysfunction and ultimately leading to nephrotoxicity.

Methyl Ferulic Acid Alleviates Neuropathic Pain by Inhibiting Nox4-induced Ferroptosis in Dorsal Root Ganglia Neurons in Rats

Neuropathic pain is a disease that has become one of the major public health problems and a global burden. Nox4-induced oxidative stress can lead to ferroptosis and neuropathic pain. Methyl ferulic acid (MFA) can inhibit the Nox4-induced oxidative stress. This study aimed to estimate whether methyl ferulic acid alleviates neuropathic pain by inhibiting the expression of Nox4 and its induction of ferroptosis. Adult male Sprague-Dawley rats were subjected to spared nerve injury (SNI) model to induce neuropathic pain. After the establishment of the model, methyl ferulic acid was given 14 days by gavage. Nox4 overexpression was induced by microinjection of the AAV-Nox4 vector. All groups measured paw mechanical withdrawal threshold (PMWT), paw thermal withdrawal latency (PTWL), and paw withdrawal cold duration (PWCD). The expression of Nox4, ACSL4, GPX4, and ROS was investigated by Western blot and immunofluorescence staining. The changes in iron content were detected by a tissue iron kit. The morphological changes in mitochondria were observed by transmission electron microscopy. In the SNI group, the paw mechanical withdrawal threshold, the paw withdrawal cold duration decreased, the paw thermal withdrawal latency did not change, the Nox4, ACSL4, ROS, and iron content increased, the GPX4 decreased, and the number of abnormal mitochondria increased. Methyl ferulic acid can increase PMWT and PWCD but does not affect PTWL. Methyl ferulic acid can inhibit Nox4 protein expression. Meanwhile, ferroptosis-related protein ACSL4 expression was decreased, GPX4 expression was increased, ROS, iron content and abnormal mitochondrial number were decreased. By overexpressing Nox4, the PMWT, PWCD, and ferroptosis of rats were more severe than those of the SNI group, but they could be reversed after treatment with methyl ferulic acid. In conclusion, methyl ferulic acid can alleviate neuropathic pain, which is related to Nox4-induced ferroptosis.

SIRT1/APE1 promotes the viability of gastric cancer cells by inhibiting p53 to suppress ferroptosis

Gastric cancer (GC) is a common cancer worldwide with high mortality. Sirtuin 1 (SIRT1) and apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) are abnormally expressed in GC cells and related to p53, which is involved in ferroptosis. Thus, we explore the mechanism via which SIRT1, APE1, and p53 impact ferroptosis in GC cells. Specifically, GC cells were transfected with small-interfering RNA for SIRT1 (SiSIRT1) or small-interfering RNA for APE1 (SiAPE1) or with short-hairpin RNA for p53, and the cell viability, Fe²⁺, malondialdehyde (MDA), and glutathione (GSH) contents were detected by cell counting kit-8 assay and enzyme-linked immunosorbent assay. Western blot, immunofluorescence, and quantitative real-time polymerase chain reaction were conducted to quantify SIRT1, APE1, p53, solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4) levels in GC cells. Silencing of SIRT1 decreased viability, GSH content, and expressions of GPX4 and SLC7A11, while increased Fe²⁺, MDA content, and p53 expression in GC cells. Such aforementioned effects were reversed by APE1 overexpression. Also, SiAPE1 generated the same effects as SiSIRT1 on the above aspects, which was offset by p53 silencing. In short, SIRT1/APE1 promotes the growth of GC cells by targeting p53 to inhibit ferroptosis.

Cyclophilin D-mediated angiotensin II-induced NADPH oxidase 4 activation in endothelial mitochondrial dysfunction that can be rescued by gallic acid

Vascular endothelial dysfunction plays a central role in the most dreadful human diseases, including stroke, tumor metastasis, and the coronavirus disease 2019 (COVID-19). Strong evidence suggests that angiotensin II (Ang II)-induced mitochondrial dysfunction is essential for endothelial dysfunction pathogenesis. However, the precise molecular mechanisms remain obscure. Here, polymerase-interacting protein 2 (Poldip 2) was found in the endothelial mitochondrial matrix and no effects on Poldip 2 and NADPH oxidase 4 (NOX 4) expression treated by Ang II. Interestingly, we first found that Ang II-induced NOX 4 binds with Poldip 2 was dependent on cyclophilin D (CypD). CypD knockdown (KD) significantly inhibited the binding of NOX 4 to Poldip 2, and mitochondrial ROS generation in human umbilical vein endothelial cells (HUVECs). Similar results were also found in cyclosporin A (CsA) treated HUVECs. Our previous study suggested a crosstalk between extracellular regulated protein kinase (ERK) phosphorylation and CypD expression, and gallic acid (GA) inhibited mitochondrial dysfunction in neurons depending on regulating the ERK-CypD axis. Here, we confirmed that GA inhibited Ang II-induced NOX 4 activation and mitochondrial dysfunction via ERK/CypD/NOX 4/Poldip 2 pathway, which provide novel mechanistic insight into CypD act as a key regulator of the NOX 4/Poldip 2 axis in Ang II-induced endothelial mitochondrial dysfunction and GA might be beneficial in the treatment of wide variety of diseases, such as COVID-19, which is worthy further research.

Ferroptosis-Related Metabolic Mechanism and Nanoparticulate Anticancer Drug Delivery Systems Based on Ferroptosis

Ferroptosis is a new type of cell death discovered in recent years that distinguishes from apoptosis and necrosis, mainly caused by the imbalance between the production and degradation of lipid reactive oxygen species in cells. Although the mechanism of ferroptosis is not yet clear, the phenomenon of ferroptosis has attracted widespread attention from researchers and has become a new hotspot in anti-tumor research. Studies have shown that ferroptosis is involved in the occurrence and development of a variety of diseases such as nervous system diseases, cardiovascular diseases and cancer. And inhibiting or inducing the occurrence of ferroptosis can effectively intervene in related diseases. At the same time, nanotechnology, by virtue of its distinct advantages, has been widely used in the development of nanodrug delivery systems. This review outlines current the advance on the intersection of ferroptosis and biomedical nanotechnology. In this review, the discovery and characteristics of ferroptosis, the mechanism of occurrence and the relationship with disease are summarized. More importantly, we summarized the strategies for inducing ferroptosis based on nanoparticulate drug delivery systems for cancer treatment.

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.

Organelle-Specific Mechanisms in Crosstalk between Apoptosis and Ferroptosis

Apoptosis has been extensively studied, whereas ferroptosis is a newly discovered form of regulated cell death that involves iron-dependent accumulations of lipid hydroperoxides. While these two cell death mechanisms were initially believed to be mutually exclusive, recent studies have revealed cellular contexts requiring a balanced interaction between them. Numerous subcellular sites and signaling molecules within these sites are involved in both processes, either as modules or switches that allow cells to choose on how to proceed. The close relationships between apoptosis and ferroptosis, as well as the possibility of switching from one to the other, are described in this review. To understand the crosstalk between apoptosis and ferroptosis, various organelle-specific mechanisms must be analyzed and compared. The ability to switch apoptosis to ferroptosis by targeting cellular organelles has a great potential in cancer therapy.

Detection of Ferroptosis in Models of Brain Diseases

Ferroptosis is a regulated form of non-apoptotic cell death driven by iron-dependent lipid peroxidation. In the past decade, ferroptosis has been reported to be involved in the pathological role in the central nervous system degenerative diseases (e.g., Alzheimer's disease, Huntington's disease, and Parkinson's disease), stroke, traumatic brain injury, and brain tumor. However, how to reliably detect and classify ferroptosis from other cell death in pathological conditions remains a great challenge, especially in primary brain cells and brain tissues. Here, we summarize the methods and protocols (such as real-time PCR, western blotting, immunofluorescence staining, lipid peroxidation assay kits and probe, immunofluorescence staining, GPX activity and glutathione depletion assay kits, iron detection, and TEM) used in the present study to detect and classify ferroptosis in the brain.

Research progress on perioperative blood-brain barrier damage and its potential mechanism

The blood-brain barrier (BBB) is an important barrier separating the central nervous system from the periphery. The composition includes endothelial cells, pericytes, astrocytes, synapses and tight junction proteins. During the perioperative period, anesthesia and surgical operations are also a kind of stress to the body, which may be accompanied by blood-brain barrier damage and brain metabolism dysfunction. Perioperative blood-brain barrier destruction is closely associated with cognitive impairment and may increase the risk of postoperative mortality, which is not conducive to enhanced recovery after surgery. However, the potential pathophysiological process and specific mechanism of blood-brain barrier damage during the perioperative period have not been fully elucidated. Changes in blood-brain barrier permeability, inflammation and neuroinflammation, oxidative stress, ferroptosis, and intestinal dysbiosis may be involved in blood-brain barrier damage. We aim to review the research progress of perioperative blood-brain barrier damage and its potential adverse effects and potential molecular mechanisms, and provide ideas for the study of homeostasis maintenance of brain function and precision anesthesia.

Activated AMPK mitigates diabetes-related cognitive dysfunction by inhibiting hippocampal ferroptosis

Clinical and preclinical interest in Type 2 diabetes (T2D)-associated cognitive dysfunction (TDACD) has grown in recent years. However, the precise mechanisms underlying TDACD need to be further elucidated. Ferroptosis was reportedly involved in neurodegenerative diseases and diabetes-related organ injuries; however, its role in TDACD remains elusive. In this study, mice fed with a high-fat-diet combined with streptozotocin (HFD-STZ) were used as a T2D model to assess the role of ferroptosis in cognitive dysfunction. We found that ferroptosis was mainly activated in hippocampal neurons but not in microglia or astrocytes. Accordingly, increased levels of transferrin receptor and decreased levels of ferritin, GPX4, and SLC7A11 were observed in hippocampal neurons. In addition, pre-treatment with liproxstatin-1, a ferroptosis inhibitor, attenuated iron accumulation and oxidative stress response, which resulted in improved cognitive function in the HFD-STZ group. Furthermore, we found that p-AMP-activated protein kinase (AMPK) was decreased in the HFD-STZ group. Pre-treatment with AMPK agonist increased the expression of AMPK and GPX4, but decreased lipocalin 2 (LCN2) in the hippocampus that resulted in improved spatial learning ability in the HFD-STZ group. Taken together, we found that activation of neuronal ferroptosis in the hippocampus contributed to cognitive impairment of HFD-STZ mice. Furthermore, AMPK activation may reduce hippocampal ferroptosis, and consequently improve cognitive performance in diabetic mice.

Exploring Dysregulated Ferroptosis-Related Genes in Septic Myocardial Injury Based on Human Heart Transcriptomes: Evidence and New Insights

Introduction

Sepsis is currently a common condition in emergency and intensive care units, and is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Cardiac dysfunction caused by septic myocardial injury (SMI) is associated with adverse prognosis and has significant economic and human costs. The pathophysiological mechanisms underlying SMI have long been a subject of interest. Recent studies have identified ferroptosis, a form of programmed cell death associated with iron accumulation and lipid peroxidation, as a pathological factor in the development of SMI. However, the current understanding of how ferroptosis functions and regulates in SMI remains limited, particularly in the absence of direct evidence from human heart.

Methods

We performed a sequential comprehensive bioinformatics analysis of human sepsis cardiac transcriptome data obtained through the GEO database. The lipopolysaccharide-induced mouse SMI model was used to validate the ferroptosis features and transcriptional expression of key genes.

Results

We identified widespread dysregulation of ferroptosis-related genes (FRGs) in SMI based on the human septic heart transcriptomes, deeply explored the underlying biological mechanisms and crosstalks, followed by the identification of key functional modules and hub genes through the construction of protein-protein interaction network. Eight key FRGs that regulate ferroptosis in SMI, including HIF1A, MAPK3, NOX4, PPARA, PTEN, RELA, STAT3 and TP53, were identified, as well as the ferroptosis features. All the key FRGs showed excellent diagnostic capability for SMI, part of them was associated with the prognosis of sepsis patients and the immune infiltration in the septic hearts, and potential ferroptosis-modulating drugs for SMI were predicted based on key FRGs.

Conclusion

This study provides human septic heart transcriptome-based evidence and brings new insights into the role of ferroptosis in SMI, which is significant for expanding the understanding of the pathobiological mechanisms of SMI and exploring promising diagnostic and therapeutic targets for SMI.

Identification and validation of ferroptosis-related hub genes in obstructive sleep apnea syndrome

Background

By 2020, the prevalence of Obstructive Sleep Apnea Syndrome (OSAS) in the US has reached 26. 6-43.2% in men and 8.7-27.8% in women. OSAS promotes hypertension, diabetes, and tumor growth through unknown means. Chronic intermittent hypoxia (CIH), sleep fragmentation, and increased pleural pressure are central mechanisms of OSAS complications. CIH exacerbates ferroptosis, which is closely related to malignancies. The mechanism of ferroptosis in OSAS disease progression remains unknown.

Methods

OSAS-related datasets (GSE135917 and GSE38792) were obtained from the GEO. Differentially expressed genes (DEGs) were screened using the R software and intersected with the ferroptosis database (FerrDb V2) to get ferroptosis-related DEGs (f-DEGs). GO, DO, KEGG, and GSEA enrichment were performed, a PPI network was constructed and hub genes were screened. The TCGA database was used to obtain the thyroid cancer (THCA) gene expression profile, and hub genes were analyzed for differential and survival analysis. The mechanism was investigated using GSEA and immune infiltration. The hub genes were validated with RT-qPCR, IHC, and other datasets. Sprague-Dawley rats were randomly separated into normoxia and CIH groups. ROS, MDA, and GSH methods were used to detect CIH-induced ferroptosis and oxidative stress.

Results

GSEA revealed a statistically significant difference in ferroptosis in OSAS (FDR < 0.05). HIF1A, ATM, HSPA5, MAPK8, MAPK14, TLR4, and CREB1 were identified as hub genes among 3,144 DEGs and 74 f-DEGs. HIF1A and ATM were the only two validated genes. F-DEGs were mainly enriched in THCA. HIF1A overexpression in THCA promotes its development. HIF1A is associated with CD8 T cells and macrophages, which may affect the immunological milieu. The result found CIH increased ROS and MDA while lowering GSH indicating that it could cause ferroptosis. In OSAS patients, non-invasive ventilation did not affect HIF1A and ATM expression. Carvedilol, hydralazine, and caffeine may be important in the treatment of OSAS since they suppress HIF1A and ATM.

Conclusions

Our findings revealed that the genes HIF1A and ATM are highly expressed in OSAS, and can serve as biomarkers and targets for OSAS.

Identifification and validation of ferroptosis signatures and immune infifiltration characteristics associated with intervertebral disc degeneration

Ferroptosis and immune infiltration play an important role in the pathogenesis of intervertebral disc degeneration (IDD). However, there is still a lack of comprehensive analysis on the interaction between ferroptosis-related genes (FRGs) and immune microenvironment in IDD patients. Therefore, this study aims to explore the correlation between FRGs characteristics and immune infiltration in the progression of IDD. The expression profiles (GSE56081 and GSE70362) and FRGs were downloaded from the comprehensive gene expression omnibus (GEO) and FerrDb database, respectively, and the differences were analyzed using R. The intersection of IDD related differential genes (DEGs) and FRGs was taken as differentially expressed FRGs (DE-FRGs) and GO and KEGG enrichment analysis was conducted. Then, we used least absolute shrinkage and selection operator (LASSO) regression algorithm and support vector machine (SVM) algorithm to screen feature genes and draw ROC curve judge the diagnostic value of key DE-FRGs. Then CIBERSORT algorithm is used to evaluate the infiltration of immune cells and analyze the correlation between key DE-FRGs and immune infiltration. Based on the analysis results, we conducted single gene GSEA analysis on key DE-FRGs. RT-PCR and immunohistochemistry further verified the clinical value of the results of biochemical analysis and screening. Seven key DE-FRGs were screened, including the upregulated genes NOX4 and PIR, and the downregulated genes TIMM9, ATF3, ENPP2, FADS2 and TFAP2A. Single gene GSEA analysis further elucidates the role of DE-FRGs in IDD associated with ferroptosis. Correlation analysis showed that seven key DE-FRGs were closely related to immune infiltration in the development of IDD. Finally, RT-PCR and immunohistochemical staining showed that NOX4, ENPP2, FADS2 and TFAP2A were statistically significant differences. In this study, we explored the connection between ferroptosis related characteristics and immune infiltration in IDD, and confirmed that NOX4, ENPP2, FADS2, and TFAP2A may become biomarkers and potential therapeutic targets for IDD.

Ferroptosis-related NFE2L2 and NOX4 Genes are Potential Risk Prognostic Biomarkers and Correlated with Immunogenic Features in Glioma

Ferroptosis is a newfound mode of regulated cell death that may have potential to associate with prognostic or diagnostic factors in glioma. In this research, 5 genes related to glioma were screened through the FerrDb database, and we analyzed the combination between genes and glioma of survival and prognosis via TCGA, GEPIA, TIMER, and other databases. Survival curve and prognostic analysis showed that the overexpression of NFE2L2 and NOX4, respectively, has a remarkable link with a worse prognosis in glioma. Then, the association between the expression of the two genes and tumor-infiltrating immune cells level was explored based on the GSCA, and the immunity of NFE2L2 and NOX4 based on the TISIDB database was also investigated. In glioma, especially GBM, there is a strong association between gene expression and immune infiltration, even in macrophages, nTreg, and Th2 cells, which play immunosuppressive functions in TME. In conclusion, these results indicate that NFE2L2 and NOX4 could be risk prognosis biomarkers in glioma, and they bound up with immune infiltration and tumor immunity in tumorigenesis.

Mitochondrial dysfunction in vascular endothelial cells and its role in atherosclerosis

The mitochondria are essential organelles that generate large amounts of ATP via the electron transport chain (ECT). Mitochondrial dysfunction causes reactive oxygen species accumulation, energy stress, and cell death. Endothelial mitochondrial dysfunction is an important factor causing abnormal function of the endothelium, which plays a central role during atherosclerosis development. Atherosclerosis-related risk factors, including high glucose levels, hypertension, ischemia, hypoxia, and diabetes, promote mitochondrial dysfunction in endothelial cells. This review summarizes the physiological and pathophysiological roles of endothelial mitochondria in endothelial function and atherosclerosis.

Ferroptosis: a potential therapeutic target for Alzheimer's disease

The most prevalent dementia-causing neurodegenerative condition is Alzheimer's disease (AD). The aberrant buildup of amyloid β and tau hyperphosphorylation are the two most well-known theories about the mechanisms underlying AD development. However, a significant number of pharmacological clinical studies conducted around the world based on the two aforementioned theories have not shown promising outcomes, and AD is still not effectively treated. Ferroptosis, a non-apoptotic programmed cell death defined by the buildup of deadly amounts of iron-dependent lipid peroxides, has received more attention in recent years. A wealth of data is emerging to support the role of iron in the pathophysiology of AD. Cell line and animal studies applying ferroptosis modulators to the treatment of AD have shown encouraging results. Based on these studies, we describe in this review the underlying mechanisms of ferroptosis; the role that ferroptosis plays in AD pathology; and summarise some of the research advances in the treatment of AD with ferroptosis modulators. We hope to contribute to the clinical management of AD.

The emerging roles of ferroptosis in cells of the central nervous system

Ferroptosis is morphologically characterized by shrunken mitochondria and biochemically characterized by iron overload, lipid peroxidation and lipid reactive oxygen species (ROS) accumulation; these phenomena are suppressed by iron chelation, genetic inhibition of cellular iron uptake, and intervention on other pathways such as lipid metabolism. The induction of ferroptosis may be related to pathological cellular conditions in the central nervous system (CNS); thus, ferroptosis may cause disability via CNS damage. Here, we review the role of ferroptosis in the main cells of the CNS, including glial cells, neurons, and pericytes; in various diseases of the CNS; and in the interaction of glia and neurons in CNS diseases. Some small molecules and traditional Chinese drugs which inhibit ferroptosis in cells of the CNS are shown as potential therapeutic strategies for neurological diseases.

A novobiocin derivative, XN4, triggers ferroptosis in gastric cancer cells via the activation of NOX4

CONTEXT

A novobiocin derivative, XN4, has been shown to promote cell apoptosis in chronic myeloid leukaemia.

OBJECTIVE

This study explores the mechanism by which XN4 promotes ferroptosis of gastric cancer (GC) cells.

MATERIALS AND METHODS

Human GC SGC-7901 and BGC-823 cells were treated with different XN4 concentrations (0, 0.1, 0.5, 1.0, 5.0, and 10.0 μmol/L) to evaluate effects of XN4. Additionally, cells were pre-treated for 24 h with si-NOX4, for 1 h with the iron chelator deferoxamine mesylate (DFO) or for 1 h with the lipid peroxidation inhibitor liproxstatin-1 before being treated with XN4 to analyse the mechanism of XN4.

RESULTS

XN4 increased cell death (IC₅₀ values of XN4 on SGC-7901 and BGC-823 cells: 1.592 ± 0.14 μmol/L and 2.022 ± 0.19 μmol/L) and Fe²⁺ levels in SGC-7901 and BGC-823 cells. These effects of 2.0 μmol/L XN4 were abolished by 100 μmol/L DFO treatment. XN4 enhanced transferrin and transferrin receptor expression to induce Fe²⁺ accumulation. XN4 decreased mitochondrial membrane potentials in GC cells, similar to erastin. Additionally, XN4 increased MDA, hydrogen peroxide, and ROS levels, but diminished total glutathione levels. Liproxstatin-1 (200 nmol/L) nullified the effects of XN4 (2.0 μmol/L) on MDA levels and cell death. Moreover, GPX4 levels decreased, but NOX4 and ferroptosis-related protein PTGS2 levels increased in GC cells following XN4 treatment, which was nullified by NOX4 knockdown.

DISCUSSION AND CONCLUSIONS

The pro-ferroptotic role of XN4 in GC might enable it to become a promising drug for GC treatment in the future despite the need for extensive research.

Breast Cancer Exosome-Derived miR-425-5p Induces Cancer-Associated Fibroblast-Like Properties in Human Mammary Fibroblasts by TGFβ1/ROS Signaling Pathway

The connection between the cellular microenvironment and tumor cells is crucial for tumor progression. However, the process by which normal fibroblasts (NFs) become cancer-associated fibroblasts (CAFs) is unknown, and mounting evidence suggests that some microRNAs (miRNAs) have an important role in converting NFs into CAFs. Breast cancer (BC) has been proven to have enhanced miR-425-5p expression in order to support progression. We discovered that human mammary fibroblasts (HMFs) could uptake BC cell line-derived exosomes to change their properties, promoting the switch to the CAF phenotype and increasing cell motility, as evidenced by an increase in CAF activation-related marker protein expression and cell proliferation, invasion, and migration. Transfection of exosomes is obtained from BC cells, and miR-425-5p inhibitors suppressed the aforementioned effects as well as lowered chemokine levels and gene expression related with proliferation and metastasis. By suppressing the expression of its target gene TGFβRII (TGFβ1 receptor), miR-425-5p enhanced the transition of HMFs to the CAF phenotype. MDA-MB-231 cells and CAFs stimulated by HMF absorption of MDA-MB-23-derived exosomes showed similar proliferation, invasion, migration, and expression of -SMA, FAP, CXCL1, IL-6, TGFβ1, P21, P27, Ki67, vimentin, E-cadherin, N-cadherin, α-catenin, fibronectin, and MMP-2. TGFβ1 overexpression enhanced ROS production. Finally, we found that HMFs transiently transfected with miR-425-5p can promote tumor growth in vivo. Finally, these findings provide fresh insight on miR-425-5p as an important mediator of the interaction between BC cells and stroma.

Identification of a key ceRNA network associated with ferroptosis in gastric cancer

Ferroptosis, a newly discovered irondependent form of regulated cell death caused by excessive accumulation of lipid peroxides, is linked to the development and treatment response of various types of cancer, including gastric cancer (GC). Noncoding RNAs (ncRNAs), as key regulators in cancer, have both oncogenic and tumor suppressive roles. However, studies on ferroptosis-related ncRNA networks in GC are still lacking. Here, we first identified 61 differentially expressed genes associated with ferroptosis in GC by computing and analyzing gene expression profile of tumor and normal tissues for GC. Then, upstream lncRNAs and miRNAs interacting with them were found through miRNet and miRBase databases, and hub lncRNAs and miRNAs were obtained through topological analysis. Finally, the ceRNA regulatory network linked to ferroptosis in GC was established, which includes two ferroptosis marker genes (TXNIP and TSC22D3), one driver gene (GABARAPL1), and one suppressor gene (CAV1). Kaplan-Meier survival analysis showed that changes in the expression of these genes were associated with the survival of GC patients. Furthermore, our study revealed that this ceRNA network may influence the progression of GC by regulating ferroptosis process. These results will help experimental researchers to design an experiment study to further explore the roles of this regulatory network in GC ferroptosis.

Sirtuin 7 mitigates renal ferroptosis, fibrosis and injury in hypertensive mice by facilitating the KLF15/Nrf2 signaling

Hypertension is one of the leading causes of chronic kidney disease characterized with renal fibrosis. This study aimed to investigate roles and mechanisms of sirtuin 7 (SIRT7) in hypertensive renal injury. Mini-pumps were implanted to male C57BL/6 mice to deliver angiotensin (Ang) Ⅱ (1.5 mg/kg/d) or saline for 2 weeks. Ang Ⅱ infusion resulted in marked increases in systolic blood pressure levels, renal ferroptosis and interstitial fibrosis in hypertensive mice, concomitantly with downregulated SIRT7 and Krüppel-like factor 15 (KLF15) levels. Notably, administration of recombinant adeno-associated virus-SIRT7 or ferroptosis inhibitor ferrostatin-1 effectively mitigated Ang Ⅱ-triggered renal ferroptosis, epithelial-mesenchymal transition (EMT), interstitial fibrosis, renal functional and structural injury in hypertensive mice by blunting the KIM-1/NOX4 signaling and enforcing the KLF15/Nrf2 and xCT/GPX4 signaling, respectively. In primary cultured mouse renal tubular epithelial cells (TECs), Ang Ⅱ pretreatment led to repressed SIRT7 expression and augmented ferroptosis as well as partial EMT, which were substantially antagonized by rhSIRT7 or ferrostatin-1 administration. Additionally, both Nrf2 inhibitor ML385 and KLF15 siRNA strikingly abolished the rhSIRT7-mediated beneficial roles in mouse renal TECs in response to Ang Ⅱ with reduced expression of Nrf2, xCT and GPX4. More importantly, ML385 administration remarkably amplified Ang Ⅱ-mediated ROS generation, lipid peroxidation and ferroptosis in renal TECs, which were significantly reversed by ferrostatin-1. In conclusion, SIRT7 alleviates renal ferroptosis, lipid peroxidation, and partial EMT under hypertensive status by facilitating the KLF15/Nrf2 signaling, thereby mitigating renal fibrosis, injury and dysfunction. Targeting SIRT7 signaling serves as a promising strategy for hypertension and hypertensive renal injury.

Ferroptosis: a double-edged sword mediating immune tolerance of cancer

The term ferroptosis was put forward in 2012 and has been researched exponentially over the past few years. Ferroptosis is an unconventional pattern of iron-dependent programmed cell death, which belongs to a type of necrosis and is distinguished from apoptosis and autophagy. Actuated by iron-dependent phospholipid peroxidation, ferroptosis is modulated by various cellular metabolic and signaling pathways, including amino acid, lipid, iron, and mitochondrial metabolism. Notably, ferroptosis is associated with numerous diseases and plays a double-edged sword role. Particularly, metastasis-prone or highly-mutated tumor cells are sensitive to ferroptosis. Hence, inducing or prohibiting ferroptosis in tumor cells has vastly promising potential in treating drug-resistant cancers. Immunotolerant cancer cells are not sensitive to the traditional cell death pathway such as apoptosis and necroptosis, while ferroptosis plays a crucial role in mediating tumor and immune cells to antagonize immune tolerance, which has broad prospects in the clinical setting. Herein, we summarized the mechanisms and delineated the regulatory network of ferroptosis, emphasized its dual role in mediating immune tolerance, proposed its significant clinical benefits in the tumor immune microenvironment, and ultimately presented some provocative doubts. This review aims to provide practical guidelines and research directions for the clinical practice of ferroptosis in treating immune-resistant tumors.

Identification of ferroptosis-related genes in syncytiotrophoblast-derived extracellular vesicles of preeclampsia

Preeclampsia (PE), defined as new-onset hypertension and multi-organ systemic complication during pregnancy, is the leading cause of maternal and neonatal mortality and morbidity. With extracellular vesicles research progresses, current data refers to the possibility that ferroptosis may play a role in exosomal effects. Evidence has suggested that ferroptosis may contribute to the pathogenesis of preeclampsia by bioinformatics analyses. The purpose of the current study is to identify the potential ferroptosis-related genes in syncytiotrophoblast-derived extracellular vesicles (STB-EVs) of preeclampsia using bioinformatics analyses. Clinical characteristics and gene expression data of all samples were obtained from the NCBI GEO database. The differentially expressed mRNAs (DE-mRNAs) in STB-EVs of preeclampsia were screened and then were intersected with ferroptosis genes. Functional and pathway enrichment analyses of ferroptosis-related DE-mRNAs in STB-EVs were performed. Ferroptosis-related hub genes in STB-EVs were identified by Cytoscape plugin CytoHubba with a Degree algorithm using a protein-protein interaction network built constructed from the STRING database. The predictive performance of ferroptosis-related hub genes was determined by a univariate analysis of receiver operating characteristic (ROC). The miRNA-hub gene regulatory network was constructed using the miRwalk database. A total of 1976 DE-mRNAs in STB-EVs were identified and the most enriched item identified by gene set enrichment analysis was signaling by G Protein-Coupled Receptors (normalized enrichment score = 1.238). These DE-mRNAs obtained 26 ferroptosis-related DE-mRNAs. Ferroptosis-related DE-mRNAs of gene ontology terms and Encyclopedia of Genes and Genomes pathway enrichment analysis were enriched significantly in response to oxidative stress and ferroptosis. Five hub genes (ALB, NOX4, CDKN2A, TXNRD1, and CAV1) were found in the constructed protein-protein interaction network with ferroptosis-related DE-mRNAs and the areas under the ROC curves for ALB, NOX4, CDKN2A, TXNRD1, and CAV1 were 0.938 (CI: 0.815-1.000), 0.833 (CI: 0.612-1.000), 0.875 (CI: 0.704-1.000), 0.958 (CI: 0.862-1.000), and 0.854 (CI: 0.652-1.000) in univariate analysis of ROC. We constructed a regulatory network of miRNA-hub gene and the findings demonstrate that hsa-miR-26b-5p, hsa-miR-192-5p, hsa-miR-124-3p, hsa-miR-492, hsa-miR-34a-5p and hsa-miR-155-5p could regulate most hub genes. In this study, we identified several central genes closely related to ferroptosis in STB-EVs (ALB, NOX4, CDKN2A, TXNRD1, and CAV1) that are potential biomarkers related to ferroptosis in preeclampsia. Our findings will provide evidence for the involvement of ferroptosis in preeclampsia and improve the understanding of ferroptosis-related molecular pathways in the pathogenesis of preeclampsia.

Light activation of iridium(III) complexes driving ROS production and DNA damage enhances anticancer activity in A549 cells

The work aimed to synthesize and characterize two iridium(III) complexes [Ir(ppy)₂(IPPH)](PF₆) (Ir1, IPPH = (2S,3R,5S,6R)-2-(2-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenoxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol, ppy = 2-phenylpyridine), [Ir(piq)₂(IPPH)](PF₆) (Ir2, piq = 1-phenylisoquinoline). The cytotoxicity of the complexes against BEL-7402, A549, HCT-116, B16 cancer cells and normal LO2 was evaluated through 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) method. The complexes show no cytotoxic activity (IC₅₀ > 100 μM) against these cancer cells, while their cytotoxicity can significantly be elevated upon illumination. The IC₅₀ values range from 0.2 ± 0.05 to 35.5 ± 3.5 μM. The cellular uptake, endoplasmic reticulum and mitochondria localization, reactive oxygen species, the change of mitochondrial membrane potential, γ-H2AX levels, cycle arrest, apoptosis and the expression of B-cell lymphoma-2 were investigated. The calreticulin (CRT), heat shock protein 70 (HSP70), high mobility group box 1 (HMGB1) were explored. This study demonstrates that photoactivatable complexes induce cell death in A549 through ROS-mediated endoplasmic reticulum stress-mitochondrial pathway, DNA damage pathways, immunogenic cell death (ICD), activation of PI3K/AKT signaling pathway and inhibit the cell growth at S phase.

A novel oxidative stress- and ferroptosis-related gene prognostic signature for distinguishing cold and hot tumors in colorectal cancer

Oxidative stress and ferroptosis exhibit crosstalk in many types of human diseases, including malignant tumors. We aimed to develop an oxidative stress- and ferroptosis-related gene (OFRG) prognostic signature to predict the prognosis and therapeutic response in patients with colorectal cancer (CRC). Thirty-four insertion genes between oxidative stress-related genes and ferroptosis-related genes were identified as OFRGs. We then performed bioinformatics analysis of the expression profiles of 34 OFRGs and clinical information of patients obtained from multiple datasets. Patients with CRC were divided into three OFRG clusters, and differentially expressed genes (DEGs) between clusters were identified. OFRG clusters correlated with patient survival and immune cell infiltration. Prognosis-related DEGs in three clusters were used to calculate the risk score, and a prognostic signature was constructed according to the risk score. In this study, patients in the low-risk group had better prognosis, higher immune cell infiltration levels, and better responses to fluorouracil-based chemotherapy and immune checkpoint blockade therapy than high-risk patients; these results were successfully validated with multiple independent datasets. Thus, low-risk CRC could be defined as hot tumors and high-risk CRC could be defined as cold tumors. To further identify potential biomarkers for CRC, the expression levels of five signature genes in CRC and adjacent normal tissues were further verified via an in vitro experiment. In conclusion, we identified 34 OFRGs and constructed an OFRG-related prognostic signature, which showed excellent performance in predicting survival and therapeutic responses for patients with CRC. This could help to distinguish cold and hot tumors in CRC, and the results might be helpful for precise treatment protocols in clinical practice.

Untargeted metabolomics analysis of the hippocampus and cerebral cortex identified the neuroprotective mechanisms of Bushen Tiansui formula in an aβ25-35-induced rat model of Alzheimer’s disease

Background: Bushen Tiansui Formula (BSTSF) is a traditional formulation of Chinese medicine that has been used to treat Alzheimer’s disease (AD) for decades; however, the underlying mechanisms by which this formula achieves such therapeutic effects have yet to be elucidated.

Prupose: To investigate the neuroprotective mechanisms of BSTSF against AD by analyzing metabolite profiles in the hippocampus and cortex of AD rats.

Methods: The rat models of AD were established by the injection of Aβ_25–35. The Morris water maze (MWM) test was performed to evaluate the effect of BSTSF treatment on cognitive dysfunction. Hematoxylin and eosin (HE) staining was used to assess the effect of BSTSF on typical AD pathologies. Underlying mechanisms were investigated using LC-MS/MS-based untargeted metabolomics analysis of the cerebral cortex and hippocampus.

Results: BSTSF significantly improved memory deficits and the typical histopathological changes of AD rats. Untargeted metabolomics analysis showed that 145 and 184 endogenous metabolites in the cerebral cortex and hippocampus, respectively, were significantly different in the BSTSF group when compared with the AD group. The differential metabolites in the cerebral cortex were primarily involved in cysteine and methionine metabolism, while those in the hippocampus were mainly involved in d-Glutamine and d-glutamate metabolism.

Conclusion: In the present study, we confirmed the neuroprotective effects of BSTSF treatment against AD using a rat model. Our findings indicate that the BSTSF-mediated protective effects were associated with amelioration of metabolic disorders in the hippocampus and cerebral cortex.