AQP4-AS1 Can Regulate the Expression of Ferroptosis-Related Regulator ALOX15 through Competitive Binding with miR-4476 in Lung Adenocarcinoma.

Background The AQP4-AS1/miR-4476-ALOX15 regulatory axis was discovered in previous studies. We aimed to investigate the regulatory mechanism of the ferroptosis-related regulator ALOX15 by AQP4-AS1 and miR-4476 in lung adenocarcinoma (LUAD) and find new targets for clinical treatment. Methods After bioinformatics analysis, we contained one ferroptosis-related gene (FRG), namely ALOX15. MicroRNAs (miRNAs) and long noncoding RNAs were predicted by miRWalk. Furthermore, we constructed overexpressed LUAD cell lines. Real-time quantitative polymerase chain reaction and western blot were used to determine the expression of mRNA and protein, respectively. Cell Counting Kit-8 (CCK-8) and EdU assay were used to detect the cell proliferation. Double luciferase assay was used to detect the binding relationship between AQP4-AS1 and miR-4464. Results ALOX15 was the most significantly downregulated FRG compared with normal tissues. Furthermore, protein-protein interaction network analysis indicated that the AQP4-AS1-miR-4476-ALOX15 regulatory axis might be involved in the occurrence and development of LUAD and there might be direct interaction between AQP4-AS1 and miR-4476, and miR-4476 and ALOX15. Furthermore, AQP4-AS1 and ALOX15 were significantly downregulated in the LUAD tissue and cell lines, whereas miR-4476 showed the opposite results ( p < 0.001). AQP4-AS1 overexpression improved the ALOX15 expression in LUAD cell lines. CCK-8 and EdU assay revealed that overexpression of AQP4-AS1 and ALOX15 inhibited the LUAD cell proliferation. Double luciferase assay results indicated that there was a combination between AQP4-AS1 and miRNA-4476. In addition, we found that overexpressed AQP4-AS1 activates the ferroptosis in LUAD cell lines. Conclusions AQP4-AS1 can regulate the expression of ALOX15 through competitive binding with miR-4476, further activate ferroptosis and inhibit the proliferation of LUAD cells.

Cerebroprotein hydrolysate-I ameliorates cognitive dysfunction in APP/PS1 mice by inhibiting ferroptosis via the p53/SAT1/ALOX15 signalling pathway.

Ferroptosis, an iron-dependent lipid peroxidation-driven cell death pathway, has been linked to the development of Alzheimer's disease (AD). However, the role of ferroptosis in the pathogenesis of AD remains unclear. Cerebroprotein hydrolysate-I (CH-I) is a mixture of peptides with neurotrophic effects that improves cognitive deficits and reduces amyloid burden. The present study investigated the ferroptosis-induced signalling pathways and the neuroprotective effects of CH-I in the brains of AD transgenic mice. Seven-month-old male APPswe/PS1dE9 (APP/PS1) transgenic mice were treated with intraperitoneal injections of CH-I and saline for 28 days. The Morris water maze test was used to assess cognitive function. CH-I significantly improved cognitive deficits and attenuated beta-amyloid (Aß) aggregation and tau phosphorylation in the hippocampus of APP/PS1 mice. RNA sequencing revealed that multiple genes and pathways, including ferroptosis-related pathways, were involved in the neuroprotective effects of CH-I. The increased levels of lipid peroxidation, ferrous ions, reactive oxygen species (ROS), and altered expression of ferroptosis-related genes (recombinant solute carrier family 7, member 11 (SLC7A11), spermidine/spermine N1-acetyltransferase 1 (SAT1) and glutathione peroxidase 4 (GPX4)) were significantly alleviated after CH-I treatment. Quantitative real-time PCR and western blotting were performed to investigate the expression of key ferroptosis-related genes and the p53/SAT1/arachidonic acid 15-lipoxygenase (ALOX15) signalling pathway. The p53/SAT1/ALOX15 signalling pathway was found to be involved in mediating ferroptosis, and the activation of this pathway was significantly suppressed in AD by CH-I. CH-I demonstrated neuroprotective effects against AD by attenuating ferroptosis and the p53/SAT1/ALOX15 signalling pathway, thus providing new targets for AD treatment.

EPA, DHA, and resolvin effects on cancer risk: The underexplored mechanisms.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplements have exhibited inconsistent effects on cancer risk, and their potential efficacy as cancer preventive agents has been increasingly questioned, especially in recent large randomized clinical trials. The role of host factors that govern EPA and DHA metabolism in relation to their impact on carcinogenesis remains understudied. Resolvins, the products of EPA and DHA oxidative metabolism, demonstrate intriguing antitumorigenic effects through mechanisms such as promoting macrophage phagocytosis of cell debris and inhibiting the production of proinflammatory chemokines and cytokines by tumor-associated macrophages (TAMs), which are crucial for cancer progression. However, clinical studies have not yet shown a significant increase in target tissue levels of resolvins with EPA and DHA supplementation. 15-Lipoxygenase-1 (ALOX15), a key enzyme in EPA and DHA oxidative metabolism, is often lost in various major human cancers, including precancerous and advanced colorectal cancers. Further research is needed to elucidate whether the loss of ALOX15 expression in colorectal precancerous and cancerous cells affects EPA and DHA oxidative metabolism, the formation of resolvins, and subsequently carcinogenesis. The findings from these studies could aid in the development of novel and effective chemoprevention interventions to reduce cancer risk.

Silencing HEATR1 Rescues Cisplatin Resistance of Non-Small Cell Lung Cancer by Inducing Ferroptosis via the p53/SAT1/ALOX15 Axis.

BACKGROUND: Cisplatin (DDP) is a commonly used chemotherapy agent. However, its resistance to the drug is a major challenge in its clinical application. Earlier research has suggested a connection between HEATR1 and chemoresistance in cancer. However, additional investigation is needed to better understand its involvement in resistance to DDP. In this study, we aimed to determine the regulatory effect of HEATR1 on the resistance of cisplatin in NSCLC. METHODS: We collected specimens of both DDP-resistant and non-resistant NSCLC to examine the expression of HEATR1. Additionally, we established cisplatin-resistant cells of NSCLC using the A549 cell line. Cell ability was examined by CCK-8 assay. Cell apoptosis and lipid ROS were examined by flow cytometry. The expressions of HEATR1, p53, SAT1, and ALOX15 were determined by qRT-PCR and Western blot. The tumor xenograft experiment was conducted to assess the impact of silencing HEATR1 on cisplatin resistance in vivo in NSCLC. RESULTS: The expression levels of HEATR1 were found to be significantly elevated in DDP-resistant tissues and cells of NSCLC as compared to non-resistant counterparts. Conversely, the expression levels of p53, SAT1, and ALOX15 were observed to be reduced in DDP-resistant cells. Through the inhibition of HEATR1, the proliferation of DDP-resistant cells was significantly suppressed, while the generation of lipid ROS was enhanced. This effect was achieved by activating ferroptosis and the p53/SAT1/ALOX15 pathway, as demonstrated both in vitro and in vivo. Conversely, the overexpression of HEATR1 exhibited opposite effects. Furthermore, the silencing of p53 and ALOX15 reversed the oncogenic effects of HEATR1 and inhibited ferroptosis in DDP-resistant NSCLC cells, suggesting the involvement of p53 and ALOX15 in HEATR1-mediated DDP resistance. CONCLUSION: Finally, the findings revealed that HEATR1 silencing reduced DDP resistance in NSCLC by inducing ferroptosis via the p53/SAT1/ALOX15 axis. HEATR1 might become a potential target for overcoming DDP resistance in NSCLC treatment.

Regulation of hepatocyte phospholipid peroxidation signaling by a Chinese patent medicine against psychological stress-induced liver injury.

BACKGROUND: Psychological stress is associated with various diseases including liver dysfunction, yet effective intervention strategies remain lacking due to the unrevealed pathogenesis mechanism. PURPOSE: This study aims to explore the relevance between BMAL1-controlled circadian rhythms and lipoxygenase 15 (ALOX15)-mediated phospholipids peroxidation in psychological stress-induced liver injury, and to investigate whether hepatocyte phospholipid peroxidation signaling is involved in the hepatoprotective effects of a Chinese patent medicine, Pien Tze Huang (PZH). METHODS: Restraint stress models were established to investigate the underlying molecular mechanisms of psychological stress-induced liver injury and the hepatoprotective effects of PZH. Redox lipidomics based on liquid chromatography-tandem mass spectrometry was applied for lipid profiling. RESULTS: The present study discovered that acute restraint stress could induce liver injury. Notably, lipidomic analysis confirmed that phospholipid peroxidation was accumulated in the livers of stressed mice. Additionally, the essential core circadian clock gene Brain and Muscle Arnt-like Protein-1 (Bmal1) was altered in stressed mice. Circadian disruption in mice, as well as BMAL1-overexpression in human HepaRG cells, also appeared to have a significant increase in phospholipid peroxidation, suggesting that stress-induced liver injury is closely related to circadian rhythm and phospholipid peroxidation. Subsequently, arachidonate 15-lipoxygenase (ALOX15), a critical enzyme that contributed to phospholipid peroxidation, was screened as a potential regulatory target of BMAL1. Mechanistically, BMAL1 promoted ALOX15 expression via direct binding to an E-box-like motif in the promoter. Finally, this study revealed that PZH treatment significantly relieved pathological symptoms of psychological stress-induced liver injury with a potential mechanism of alleviating ALOX15-mediated phospholipid peroxidation. CONCLUSION: Our findings illustrate the critical role of BMAL1-triggered phospholipid peroxidation in psychological stress-induced liver injury and provide new insight into treating psychological stress-associated liver diseases by TCM intervention.

Identifying ALOX15-initiated lipid peroxidation increases susceptibility to ferroptosis in asthma epithelial cells.

Ferroptosis is a programmed form of cell death regulated by iron and has been linked to the development of asthma. However, the precise mechanisms driving ferroptosis in asthma remain elusive. To gain deeper insights, we conducted an analysis of nasal epithelial and sputum samples from the GEO database using three machine learning methods. Our investigation identified a pivotal gene, Arachidonate 15-lipoxygenase (ALOX15), associated with ferroptosis in asthma. Through both in vitro and in vivo experiments, we further confirmed the significant role of ALOX15 in ferroptosis in asthma. Our results demonstrate that ferroptosis manifests in an HDM/LPS-induced allergic airway inflammation (AAI) mouse model, mimicking human asthma, and in HDM/LPS-stimulated 16HBE cells. Moreover, we observed an up-regulation of ALOX15 expression in HDM/LPS-induced mice and cells. Notably, silencing ALOX15 markedly decreased HDM/LPS-induced ferroptosis in 16HBE cells. These findings indicate that ferroptosis may be implicated in the onset and progression of asthma, with ALOX15-induced lipid peroxidation raising the susceptibility to ferroptosis in asthmatic epithelial cells.

Rhythm gene PER1 mediates ferroptosis and lipid metabolism through SREBF2/ALOX15 axis in polycystic ovary syndrome.

OBJECTIVE: This work aimed to investigate the role of rhythm gene PER1 in mediating granulosa cell ferroptosis and lipid metabolism of polycystic ovary syndrome (PCOS). METHODS: We injected dehydroepiandrosterone and Ferrostatin-1 (Fer-1) into mice to explore the mechanism of ferroptosis in PCOS. The effect of PER1 on ferroptosis-like changes in granulosa cells was explored by overexpression of PER1 plasmid transfection and Fer-1 treatment. RESULTS: We found that Fer-1 ameliorated the characteristic polycystic ovary morphology, suppressed ferroptosis in the PCOS mice. PER1 and ALOX15 were highly expressed in PCOS, whereas SREBF2 was lowly expressed. Overexpression of PER1 decreased granulosa cell viability and inhibited proliferation. Meanwhile, overexpression of PER1 increased lipid reactive oxygen species, 4-Hydroxynonenal (4-HNE), Malondialdehyde (MDA), total Fe, and Fe2+ levels in granulosa cells and decreased Glutathione (GSH) content. Fer-1, SREBF2 overexpression, or ALOX15 silencing treatment reversed the effects of PER1 overexpression on granulosa cells. PER1 binds to the SREBF2 promoter and represses SREBF2 transcription. SREBF2 binds to the ALOX15 promoter and represses ALOX15 transcription. Correlation analysis of clinical trials showed that PER1 was positively correlated with total cholesterol, low-density lipoprotein cholesterol, luteinizing hormone, testosterone, 4-HNE, MDA, total Fe, Fe2+, and ALOX15. In contrast, PER1 was negatively correlated with SREBF2, high-density lipoprotein cholesterol, follicle-stimulating hormone, progesterone, and GSH. CONCLUSION: This study demonstrates that the rhythm gene PER1 promotes ferroptosis and dysfunctional lipid metabolism in granulosa cells in PCOS by inhibiting SREBF2/ALOX15 signaling.

Association between arachidonate lipoxygenase 15,c.-292 C > T gene polymorphism and non-cystic fibrosis bronchiectasis in children: a pilot study on the effects on airway lipoxin A4 and disease phenotype.

BACKGROUND: Persistent airway inflammation is a central feature of bronchiectasis. Arachidonate 15-lipoxygenase (ALOX-15) controls production of endogenous lipid mediators, including lipoxins that regulate airway inflammation. Mutations at various positions in ALOX-15 gene can influence airway disease development. We investigated association between ALOX-15,c.-292 C > T gene polymorphism and bronchiectasis unrelated to cystic fibrosis in Egyptian children. Also, lipoxin A4 (LXA4) level in bronchoalveolar lavage (BAL) was studied in relation to polymorphism genotypes and disease phenotypes determined by clinical, pulmonary functions, and radiological severity parameters. METHODS: This was an exploratory study that included 60 participants. Thirty children with non-cystic fibrosis bronchiectasis (NCFB) were compared with 30 age and sex-matched controls. ALOX-15,c.-292 C > T polymorphism was genotyped using TaqMan-based Real-time PCR. LXA4 was measured in BAL using ELISA method. RESULTS: There was no significant difference between patients and controls regarding ALOX-15,c.-292 C > T polymorphism genotypes and alleles (OR = 1.75; 95% CI (0.53-5.7), P = 0.35) (OR = 1; 95% CI (0.48-2), p = 1). BAL LXA4 level was significantly lower in patients, median (IQR) of 576.9 (147.6-1510) ng/ml compared to controls, median (IQR) of 1675 (536.8-2542) (p = 0.002). Patients with severe bronchiectasis had a significantly lower LXA4 level (p < 0.001). There were significant correlations with exacerbations frequency (r=-0.54, p = 0.002) and FEV1% predicted (r = 0.64, p = 0.001). Heterozygous CT genotype carriers showed higher LXA4 levels compared to other genotypes(p = 0.005). CONCLUSIONS: Low airway LXA4 in children with NCFB is associated with severe disease phenotype and lung function deterioration. CT genotype of ALOX-15,c.-292 C > T polymorphism might be a protective genetic factor against bronchiectasis development and/or progression due to enhanced LXA4 production.

Identification of core gene in chronic rhinosinusitis with nasal polyps and correlations with inflammation-related genes.

OBJECTIVE: Our aim in this study is to identify the core genes of chronic rhinosinusitis with nasal polyps and analyze the correlations between it and inflammation-related genes. METHODS: GSE72713 dataset containing gene expression data of ECRSwNP, nonECRSwNP and healthy samples was obtained from Gene Expression Omnibus (GEO) and filtered by limma to identify DEGs among three groups, then the functions and correlated pathways of DEGs were analyzed using GO and KEGG. The core DEGs were selected by the intersection of DEGs and the PPI network was constructed via STRING. The correlations between the expression levels of CRSwNP core gene and inflammation-related genes were analyzed via the Mann-Whitney U test. RESULTS: The DEGs among ECRSwNP, nonECRSwNP, and CTRL were filtered respectively, and enrichment analysis showed they were associated with olfaction and/or immune responses. The PPI network was constructed by 7 core DEGs obtained via the intersection among three groups, and ALOX15 was confirmed as the core gene in the network. Subsequently, the correlations between the expression levels of ALOX15 and inflammation-related genes were illustrated. CONCLUSION: In this study, the core gene ALOX15 was selected from the DEGs among ECRSwNP, nonECRSwNP, and CTRL. IL5, IL1RL1, and IL1RAP were found to exhibit a significant positive correlation with ALOX15. LEVEL OF EVIDENCE: Level 3.

Corrigendum: Arachidonate 15-lipoxygenase-mediated production of Resolvin D5n-3 DPA abrogates pancreatic stellate cell-induced cancer cell invasion.

[This corrects the article DOI: 10.3389/fimmu.2023.1248547.].

Development of novel ALOX15 inhibitors combining dual machine learning filtering and fragment substitution optimisation approaches, molecular docking and dynamic simulation methods.

The oxidation of unsaturated lipids, facilitated by the enzyme Arachidonic acid 15-lipoxygenase (ALOX15), is an essential element in the development of ferroptosis. This study combined a dual-score exclusion strategy with high-throughput virtual screening, naive Bayesian and recursive partitioning machine learning models, the already established ALOX15 inhibitor i472, and a docking-based fragment substitution optimisation approach to identify potential ALOX15 inhibitors, ultimately leading to the discovery of three FDA-approved drugs that demonstrate optimal inhibitory potential against ALOX15. Through fragment substitution-based optimisation, seven new inhibitor structures have been developed. To evaluate their practicality, ADMET predictions and molecular dynamics simulations were performed. In conclusion, the compounds found in this study provide a novel approach to combat conditions related to ferroptosis-related injury by inhibiting ALOX15.

Identification of core gene in chronic rhinosinusitis with nasal polyps and correlations with inflammation-related genes

Abstract Objective Our aim in this study is to identify the core genes of chronic rhinosinusitis with nasal polyps and analyze the correlations between it and inflammation-related genes. Methods GSE72713 dataset containing gene expression data of ECRSwNP, nonECRSwNP and healthy samples was obtained from Gene Expression Omnibus (GEO) and filtered by limma to identify DEGs among three groups, then the functions and correlated pathways of DEGs were analyzed using GO and KEGG. The core DEGs were selected by the intersection of DEGs and the PPI network was constructed via STRING. The correlations between the expression levels of CRSwNP core gene and inflammation-related genes were analyzed via the Mann-Whitney U test. Results The DEGs among ECRSwNP, nonECRSwNP, and CTRL were filtered respectively, and enrichment analysis showed they were associated with olfaction and/or immune responses. The PPI network was constructed by 7 core DEGs obtained via the intersection among three groups, and ALOX15 was confirmed as the core gene in the network. Subsequently, the correlations between the expression levels of ALOX15 and inflammation-related genes were illustrated. Conclusion In this study, the core gene ALOX15 was selected from the DEGs among ECRSwNP, nonECRSwNP, and CTRL. IL5, IL1RL1, and IL1RAP were found to exhibit a significant positive correlation with ALOX15. Level of Evidence Level 3.

Biomimetic Macrophage Membrane-Camouflaged Nanoparticles Induce Ferroptosis by Promoting Mitochondrial Damage in Glioblastoma.

The increasing understanding of ferroptosis has indicated its role and therapeutic potential in cancer; however, this knowledge has yet to be translated into effective therapies. Glioblastoma (GBM) patients face a bleak prognosis and encounter challenges due to the limited treatment options available. In this study, we conducted a genome-wide CRISPR-Cas9 screening in the presence of a ferroptosis inducer (RSL3) to identify the key driver genes involved in ferroptosis. We identified ALOX15, a key lipoxygenase (LOX), as an essential driver of ferroptosis. Small activating RNA (saRNA) was used to mediate the expression of ALOX15 promoted ferroptosis in GBM cells. We then coated saALOX15-loaded mesoporous polydopamine (MPDA) with Angiopep-2-modified macrophage membranes (MMs) to reduce the clearance by the mononuclear phagocyte system (MPS) and increase the ability of the complex to cross the blood-brain barrier (BBB) during specific targeted therapy of orthotopic GBM. These generated hybrid nanoparticles (NPs) induced ferroptosis by mediating mitochondrial dysfunction and rendering mitochondrial morphology abnormal. In vivo, the modified MM enabled the NPs to target GBM cells, exert a marked inhibitory effect on GBM progression, and promote GBM radiosensitivity. Our results reveal ALOX15 to be a promising therapeutic target in GBM and suggest a biomimetic strategy that depends on the biological properties of MMs to enhance the in vivo performance of NPs for treating GBM.

Arachidonate 15-lipoxygenase-mediated production of Resolvin D5n-3 DPA abrogates pancreatic stellate cell-induced cancer cell invasion.

Activation of pancreatic stellate cells (PSCs) to cancer-associated fibroblasts (CAFs) is responsible for the extensive desmoplastic reaction observed in PDAC stroma: a key driver of pancreatic ductal adenocarcinoma (PDAC) chemoresistance leading to poor prognosis. Specialized pro-resolving mediators (SPMs) are prime modulators of inflammation and its resolution, traditionally thought to be produced by immune cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipid mediator profiling PSCs as well as primary human CAFs express enzymes and receptors to produce and respond to SPMs. Human PSC/CAF SPM secretion profile can be modulated by rendering these cells activated [transforming growth factor beta (TGF-ß)] or quiescent [all-trans retinoic acid (ATRA)]. ATRA-induced nuclear translocation of arachidonate-15-lipoxygenase (ALOX15) was linked to increased production of n-3 docosapentaenoic acid-derived Resolvin D5 (RvD5n-3 DPA), among other SPMs. Inhibition of RvD5n-3 DPA formation increases cancer cell invasion, whereas addback of this molecule reduced activated PSC-mediated cancer cell invasion. We also observed that circulating concentrations of RvD5n-3 DPA levels were decreased in peripheral blood of metastatic PDAC patients when compared with those measured in plasma of non-metastatic PDAC patients. Together, these findings indicate that RvD5n-3 DPA may regulate cancer-stroma cross-talk and invasion.

Middle meatus microbiome in patients with eosinophilic chronic rhinosinusitis in a Japanese population.

BACKGROUND: Chronic rhinosinusitis (CRS) is a common chronic inflammatory disease and is subdivided into eosinophilic and noneosinophilic forms. There are few reports investigating the nasal microbiome and its pathological functions in patients with CRS. OBJECTIVE: We sought to analyze factors contributing to variations of the nasal microbiome in CRS, and on the basis of these factors, to elucidate whether the bacterial metabolites were related to the pathogenesis. METHODS: Nasal swabs were collected, and the V3 to V4 variable region of the 16S ribosomal RNA gene was amplified and sequenced. Factors contributing to variations of the nasal microbiome in patients with CRS were compared. The most influential factor was whether CRS was eosinophilic, and we compared α- and ß-diversity, bacterial species, and predictive bacterial functions between the 2 patient groups. In addition, the metabolites of the key bacteria were extracted, and we evaluated the predicted bacterial functions in airway epithelial cells. RESULTS: In total, 110 patients with CRS and 33 control subjects were enrolled. On the basis of the factors of variation, it was found that patients with eosinophilic CRS (n = 65) had different microbiomes with weighted UniFrac ß-diversity and lower α-diversity compared with those with noneosinophilic CRS (n = 45). A higher abundance of Fusobacterium nucleatum and an increased LPS pathway were observed in patients with noneosinophilic CRS compared with those with eosinophilic CRS. In airway epithelial cells, LPS derived from F nucleatum suppressed the expression levels of ALOX15 induced by TH2 cytokines. CONCLUSIONS: The differences in the nasal microbiome may play a key role in the pathophysiology of CRS.

Baicalein, a component of banxia xiexin decoction, alleviates CPT-11-induced gastrointestinal dysfunction by inhibiting ALOX15-mediated ferroptosis.

Baicalein, one of the active ingredients of banxia xiexin decoction, has good therapeutic efficacy in treating diarrhea and improving gastrointestinal dysfunction. The role and mechanism of Baicalein on irinotecan (CPT-11)-induced gastrointestinal dysfunction are the focus of this study. Concretely, CPT-11 induced delayed diarrhea rat model and intestinal epithelial cell (IEC)-6 cell injury model with Baicalein treatment as needed. Colonic pathological changes were analyzed by hematoxylin-eosin staining, and inflammatory factor expressions in serum were determined by enzyme-linked immunosorbent assay. Immunohistochemistry and western blot were performed to quantify ferroptosis-related protein expressions. Thiobarbituric acid reactive substances (TBARS) kits and colorimetric assay kit were applied to detect lipid peroxidation levels and Fe2+ content, respectively. In vitro experiments also included quantitative real-time polymerase chain reaction, cell counting kit-8, and C11 BODIPY staining. CPT-11 induced aggravation of intestinal tissue damage, inflammatory factor release, Fe2+ accumulation, upregulation of lipid peroxidation and 15-Lipoxygenase (ALOX15) expression, and downregulation of glutathione peroxidase 4 (Gpx4) and SLC7A11 in vivo in rats; however, Baicalein dose-dependently reversed the effects of CPT-11. Baicalein elevated cell viability, reduced lipid peroxidation and Fe2+ accumulation, and elevated Gpx4 and SLC7A11 levels, whereas ALOX15 overexpression reversed the effects of Baicalein on a CPT-11-induced IEC-6 cell injury model. In conclusion, Baicalein plays a mitigating role in CPT-11-induced delayed diarrhea via ALOX15-mediated ferroptosis.

The suppression of cervical cancer ferroptosis by macrophages: The attenuation of ALOX15 in cancer cells by macrophages-derived exosomes.

Induction of cancer cell ferroptosis has been proposed as a potential treatment in several cancer types. Tumor-associated macrophages (TAMs) play a key role in promoting tumor malignant progression and therapy resistance. However, the roles and mechanisms of TAMs in regulating tumor ferroptosis is still unexplored and remains enigmatic. This study shows ferroptosis inducers has shown therapeutic outcomes in cervical cancer in vitro and in vivo. TAMs have been found to suppress cervical cancer cells ferroptosis. Mechanistically, macrophage-derived miRNA-660-5p packaged into exosomes are transported into cancer cells. In cancer cells, miRNA-660-5p attenuates ALOX15 expression to inhibit ferroptosis. Moreover, the upregulation of miRNA-660-5p in macrophages depends on autocrine IL4/IL13-activated STAT6 pathway. Importantly, in clinical cervical cancer cases, ALOX15 is negatively associated with macrophages infiltration, which also raises the possibility that macrophages reduce ALOX15 levels in cervical cancer. Moreover, both univariate and multivariate Cox analyses show ALOX15 expression is independent prognostic factor and positively associated with good prognosis in cervical cancer. Altogether, this study reveals the potential utility of targeting TAMs in ferroptosis-based treatment and ALOX15 as prognosis indicators for cervical cancer.

Overexpression of LOX-1 in hepatocytes protects vascular smooth muscle cells from phenotype transformation and wire injury induced carotid neoatherosclerosis through ALOX15.

Neoatherosclerosis (NA), the main pathological basis of late stent failure, is the main limitation of interventional therapy. However, the specific pathogenesis and treatment remain unclear. In vivo, NA model was established by carotid wire injury and high-fat feeding in ApoE-/- mice. Oxidized low-density lipoprotein receptor-1/lectin-like oxidized low-density lipoprotein receptor-1 (OLR1/LOX-1), a specific receptor for oxidized low-density lipoprotein (ox-LDL), was specifically ectopically overexpressed in hepatocytes by portal vein injection of adeno-associated serotype 8 (AAV8)-thyroid binding globulin (TBG)-Olr1 and the protective effect against NA was examined. In vitro, LOX-1 was overexpressed on HHL5 using lentivirus (LV)-OLR1 and the vascular smooth muscle cells (VSMCs)-HHL5 indirect co-culture system was established to examine its protective effect on VSMCs and the molecular mechanism. Functionally, we found that specific ectopic overexpression of LOX-1 by hepatocytes competitively engulfed and metabolized ox-LDL, alleviating its resulting phenotypic transformation of VSMCs including migration, downregulation of contractile shape markers (smooth muscle α-actin (SMαA) and smooth muscle-22α (SM22α)), and upregulation of proliferative/migratory shape markers (osteopontin (OPN) and Vimentin) as well as foaminess and apoptosis, thereby alleviating NA, which independent of low-density lipoprotein (LDL) lowering treatment (evolocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9)). Mechanistically, we found that overexpression of LOX-1 in hepatocytes competitively engulfed and metabolized ox-LDL through upregulation of arachidonate-15-lipoxygenase (ALOX15), which further upregulated scavenger receptor class B type I (SRBI) and ATP-binding cassette transporter A1 (ABCA1). In conclusion, the overexpression of LOX-1 in liver protects VSMCs from phenotypic transformation and wire injury induced carotid neoatherosclerosis through ALOX15.

Electroacupuncture Alleviates Neuropathic Pain by Suppressing Ferroptosis in Dorsal Root Ganglion via SAT1/ALOX15 Signaling.

Neuropathic pain affects globally about 7-10% of the general population. Electroacupuncture (EA) effectively relieves neuropathic pain symptoms without causing any side effects; however, the underlying molecular mechanisms remain unclear. We established a chronic constriction injury (CCI)-induced rat model of neuropathic pain. RNA sequencing was used to screen for differentially expressed genes in the dorsal root ganglion after CCI and EA treatment. We identified gene markers of ferroptosis spermidine/spermine N1-acetyltransferase 1 (Sat1) and arachidonate 15-lipoxygenase (Alox15) to be dysregulated in the CCI-induced neuropathic pain model. Furthermore, EA relieved CCI-induced pain as well as ferroptosis-related symptoms in the dorsal root ganglion, including lipid peroxidation and iron overload. Finally, SAT1 knockdown also alleviated mechanical and thermal pain hypersensitivity and reversed ferroptosis damage. In conclusion, we showed that EA inhibited ferroptosis by regulating the SAT1/ALOX15 pathway to treat neuropathic pain. Our findings provide insight into the mechanisms of EA and suggest a novel therapeutic target for neuropathic pain.

Paradoxical Induction of ALOX15/15B by Cortisol in Human Amnion Fibroblasts: Implications for Inflammatory Responses of the Fetal Membranes at Parturition.

Inflammation of the fetal membranes is an indispensable event of parturition, with increasing prostaglandin E2 (PGE2) synthesis as one of the ultimate products that prime labor onset. In addition to PGE2, the fetal membranes also boast a large capacity for cortisol regeneration. It is intriguing how increased PGE2 synthesis is achieved in the presence of increasing amounts of classical anti-inflammatory glucocorticoids in the fetal membranes at parturition. 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) synthesized by lipoxygenase 15/15B (ALOX15/15B) has been shown to enhance inflammation-induced PGE2 synthesis in amnion fibroblasts. Here, we examined whether glucocorticoids could induce ALOX15/15B expression and 15(S)-HETE production to promote PGE2 synthesis in amnion fibroblasts at parturition. We found that cortisol and 15(S)-HETE abundance increased parallelly in the amnion at parturition. Cortisol induced ALOX15/15B expression and 15(S)-HETE production paradoxically in amnion fibroblasts. Mechanism study revealed that this paradoxical induction was mediated by p300-mediated histone acetylation and interaction of glucocorticoid receptor with transcription factors CREB and STAT3. Conclusively, cortisol regenerated in the fetal membranes can paradoxically induce ALOX15/15B expression and 15(S)-HETE production in human amnion fibroblasts, which may further assist in the induction of PGE2 synthesis in the inflammatory responses of the fetal membranes for parturition.