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Epp N, Fürstenberger G, Müller K, de Juanes S, Leitges M, Hausser I, Thieme F, Liebisch G, Schmitz G, Krieg P. 12R-lipoxygenase deficiency disrupts epidermal barrier function. ACTA ACUST UNITED AC 2007; 177:173-82. [PMID: 17403930 PMCID: PMC2064121 DOI: 10.1083/jcb.200612116] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
12R-lipoxygenase (12R-LOX) and the epidermal LOX-3 (eLOX-3) constitute a novel LOX pathway involved in terminal differentiation in skin. This view is supported by recent studies showing that inactivating mutations in 12R-LOX and eLOX-3 are linked to the development of autosomal recessive congenital ichthyosis. We show that 12R-LOX deficiency in mice results in a severe impairment of skin barrier function. Loss of barrier function occurs without alterations in proliferation and stratified organization of the keratinocytes, but is associated with ultrastructural anomalies in the upper granular layer, suggesting perturbance of the assembly/extrusion of lamellar bodies. Cornified envelopes from skin of 12R-LOX–deficient mice show increased fragility. Lipid analysis demonstrates a disordered composition of ceramides, in particular a decrease of ester-bound ceramide species. Moreover, processing of profilaggrin to monomeric filaggrin is impaired. This study indicates that the 12R-LOX–eLOX-3 pathway plays a key role in the process of epidermal barrier acquisition by affecting lipid metabolism, as well as protein processing.
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Abstract
Vitamin E is essential for normal neurological function. It is the major lipid-soluble, chain-breaking antioxidant in the body, protecting the integrity of membranes by inhibiting lipid peroxidation. Mostly on the basis of symptoms of primary vitamin E deficiency, it has been demonstrated that vitamin E has a central role in maintaining neurological structure and function. Orally supplemented vitamin E reaches the cerebrospinal fluid and brain. Vitamin E is a generic term for all tocopherols and their derivatives having the biological activity of RRR-alpha-tocopherol, the naturally occurring stereoisomer compounds with vitamin E activity. In nature, eight substances have been found to have vitamin E activity: alpha-, beta-, gamma- and delta-tocopherol; and alpha-, beta-, gamma- and delta-tocotrienol. Often, the term vitamin E is synonymously used with alpha-tocopherol. Tocotrienols, formerly known as zeta, , or eta-tocopherols, are similar to tocopherols except that they have an isoprenoid tail with three unsaturation points instead of a saturated phytyl tail. Although tocopherols are predominantly found in corn, soybean, and olive oils, tocotrienols are particularly rich in palm, rice bran, and barley oils. Tocotrienols possess powerful antioxidant, anticancer, and cholesterol-lowering properties. Recently, we have observed that alpha-tocotrienol is multi-fold more potent than alpha-tocopherol in protecting HT4 and primary neuronal cells against toxicity induced by glutamate as well as by a number of other toxins. At nanomolar concentration, tocotrienol, but not tocopherol, completely protected neurons by an antioxidant-independent mechanism. Our current work identifies two major targets of tocotrienol in the neuron: c-Src kinase and 12-lipoxygenase. Dietary supplementation studies have established that tocotrienol, fed orally, does reach the brain. The current findings point towards tocotrienol as a potent neuroprotective form of natural vitamin E.
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Zhang XJ, Liu X, Hu M, Zhao GJ, Sun D, Cheng X, Xiang H, Huang YP, Tian RF, Shen LJ, Ma JP, Wang HP, Tian S, Gan S, Xu H, Liao R, Zou T, Ji YX, Zhang P, Cai J, Wang ZV, Meng G, Xu Q, Wang Y, Ma XL, Liu PP, Huang Z, Zhu L, She ZG, Zhang X, Bai L, Yang H, Lu Z, Li H. Pharmacological inhibition of arachidonate 12-lipoxygenase ameliorates myocardial ischemia-reperfusion injury in multiple species. Cell Metab 2021; 33:2059-2075.e10. [PMID: 34536344 DOI: 10.1016/j.cmet.2021.08.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/01/2020] [Accepted: 08/25/2021] [Indexed: 12/18/2022]
Abstract
Myocardial ischemia-reperfusion (MIR) injury is a major cause of adverse outcomes of revascularization after myocardial infarction. To identify the fundamental regulator of reperfusion injury, we performed metabolomics profiling in plasma of individuals before and after revascularization and identified a marked accumulation of arachidonate 12-lipoxygenase (ALOX12)-dependent 12-HETE following revascularization. The potent induction of 12-HETE proceeded by reperfusion was conserved in post-MIR in mice, pigs, and monkeys. While genetic inhibition of Alox12 protected mouse hearts from reperfusion injury and remodeling, Alox12 overexpression exacerbated MIR injury. Remarkably, pharmacological inhibition of ALOX12 significantly reduced cardiac injury in mice, pigs, and monkeys. Unexpectedly, ALOX12 promotes cardiomyocyte injury beyond its enzymatic activity and production of 12-HETE but also by its suppression of AMPK activity via a direct interaction with its upstream kinase TAK1. Taken together, our study demonstrates that ALOX12 is a novel AMPK upstream regulator in the post-MIR heart and that it represents a conserved therapeutic target for the treatment of myocardial reperfusion injury.
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Herre S, Schadendorf T, Ivanov I, Herrberger C, Steinle W, Rück-Braun K, Preissner R, Kuhn H. Photoactivation of an Inhibitor of the 12/15‐Lipoxygenase Pathway. Chembiochem 2006; 7:1089-95. [PMID: 16755628 DOI: 10.1002/cbic.200600082] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Lipoxygenases are lipid-peroxidizing enzymes that have been implicated in the pathogenesis of inflammatory diseases and lipoxygenase inhibitors may be developed as anti-inflammatory drugs. Structure comparison with known lipoxygenase inhibitors has suggested that (2Z)-2-(3-benzylidene)-3-oxo-2,3-dihydrobenzo[b]thiophene-7-carboxylic acid methyl ester might inhibit the lipoxygenase pathway but we found that it exhibited only a low inhibitory potency for the pure 12/15-lipoxygenase (IC(50) = 0.7 mM). However, photoactivation, which induces a Z-to-E isomerization of the double bond, strongly augmented the inhibitory potency and an IC(50) value of 0.021 mM was determined for the pure E isomer. Similar isomer-specific differences were observed with the recombinant enzyme and its 12-lipoxygenating Ile418Ala mutant, as well as in intracellular lipoxygenase activity. Structure modeling of the enzyme/inhibitor complex suggested the molecular reasons for this isomer specificity. Since light-induced isomerization may proceed in the skin, such photoreactive compounds might be developed as potential drugs for inflammatory skin diseases.
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Abstract
Chronic unresolved inflammation contributes to the development of nonalcoholic steatohepatitis (NASH), a disorder characterized by lipotoxicity, fibrosis, and progressive liver dysfunction. In this issue of the JCI, Han et al. report that maresin 1 (MaR1), a proresolving lipid mediator, mitigates NASH by reprograming macrophages to an antiinflammatory phenotype. Mechanistically, they identified retinoic acid-related orphan receptor α (RORα) as both a target and autocrine regulator of MaR1 production. Because NASH is associated with many widely occurring metabolic diseases, including obesity and type 2 diabetes, identification of this endogenous protective pathway could have broad therapeutic implications.
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Lei B, Wu H, You G, Wan X, Chen S, Chen L, Wu J, Zheng N. Silencing of ALOX15 reduces ferroptosis and inflammation induced by cerebral ischemia-reperfusion by regulating PHD2/HIF2α signaling pathway. Biotechnol Genet Eng Rev 2024; 40:4341-4360. [PMID: 37154013 DOI: 10.1080/02648725.2023.2210449] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 05/01/2023] [Indexed: 05/10/2023]
Abstract
OBJECTIVE To investigate the potential mechanism of arachidonic acid deoxyribozyme 15 (ALOX15) in ferroptosis and inflammation induced by cerebral ischemia reperfusion injury. METHODS The mice and cell models of cerebral ischemia-reperfusion injury were constructed. Western Blot was used to detect the protein expression levels of ALOX15, glutathione peroxidase (GPX4), hypoxia-inducible factor-2α (HIF-2α), prolyl hydroxylase (PHD) and inflammatory factors (NLRP3, IL-1β, IL-18) in brain tissues and cells. Cell proliferation activity was detected by CCK-8 method. LDH assay was used to detect the release of lactate dehydrogenase. TTC staining was used to observe cerebral infarction. RESULTS In cerebral ischemia-reperfusion mice and cell models, the expression of ALOX15 protein was increased, the expression of GPX4, a key marker of ferroptosis was decreased, and silencing of ALOX15 down-regulated the GPX4 expression. HIF-2α expression was down-regulated in animal and cell models of cerebral ischemia reperfusion, and silencing of ALOX15 increased the HIF-2α expression by inhibiting PHD2 expression. Inhibition of ALOX15 expression reduced inflammatory factors levels (NLRP3, IL-1β, and IL-18) in cerebral ischemia. Inhibitor of PHD2 (IXOC-4) alleviating brain injury and cell death induced by cerebral ischemia reperfusion and stabilize HIF-2α expression in vivo. CONCLUSION The expression of ALOX15 was up-regulated in cerebral ischemia-reperfusion animals and cells model. Inhibition of ALOX15 up-regulated the GPX4 expression, and promoted HIF-2α expression by inhibiting PHD2, thus alleviating ferroptosis and inflammation caused by cerebral ischemia-reperfusion injury.
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Hébert MPA, Selka A, Lebel AA, Doiron JA, Isabel Chiasson A, Gauvin VL, Matthew AJ, Hébert MJG, Doucet MS, Joy AP, Barnett DA, Touaibia M, Surette ME, Boudreau LH. Caffeic acid phenethyl ester analogues as selective inhibitors of 12-lipoxygenase product biosynthesis in human platelets. Int Immunopharmacol 2023; 121:110419. [PMID: 37295028 DOI: 10.1016/j.intimp.2023.110419] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/17/2023] [Accepted: 05/30/2023] [Indexed: 06/11/2023]
Abstract
The inflammatory response is an essential process for the host defence against pathogens. Lipid mediators are important in coordinating the pro-inflammatory and pro-resolution phases of the inflammatory process. However, unregulated production of these mediators has been associated with chronic inflammatory diseases such as arthritis, asthma, cardiovascular diseases, and several types of cancer. Therefore, it is not surprising that enzymes implicated in the production of these lipid mediators have been targeted for potential therapeutic approaches. Amongst these inflammatory molecules, the 12-hydroxyeicosatetraenoic acid (12(S)-HETE) is abundantly produced in several diseases and is primarily biosynthesized via the platelet's 12-lipoxygenase (12-LO) pathway. To this day, very few compounds selectively inhibit the 12-LO pathway, and most importantly, none are currently used in the clinical settings. In this study, we investigated a series of polyphenol analogues of natural polyphenols that inhibit the 12-LO pathway in human platelets without affecting other normal functions of the cell. Using an ex vivo approach, we found one compound that selectively inhibited the 12-LO pathway, with IC50 values as low as 0.11 µM, with minimal inhibition of other lipoxygenase or cyclooxygenase pathways. More importantly, our data show that none of the compounds tested induced significant off-target effects on either the platelet's activation or its viability. In the continuous search for specific and better inhibitors targeting the regulation of inflammation, we characterized two novel inhibitors of the 12-LO pathway that could be promising for subsequent in vivo studies.
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Kanai M, Nishino T, Daassi D, Kimura A, Liao CW, Javanfekr Shahri Z, Wakimoto A, Gogoleva N, Usui T, Morito N, Arita M, Takahashi S, Hamada M. MAFB in Macrophages Regulates Prostaglandin E2-Mediated Lipid Mediator Class Switch through ALOX15 in Ischemic Acute Kidney Injury. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 213:1212-1224. [PMID: 39230290 PMCID: PMC11457724 DOI: 10.4049/jimmunol.2300844] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 07/31/2024] [Indexed: 09/05/2024]
Abstract
Monocytes and macrophages express the transcription factor MAFB (V-maf musculoaponeurotic fibrosarcoma oncogene homolog B) and protect against ischemic acute kidney injury (AKI). However, the mechanism through which MAFB alleviates AKI in macrophages remains unclear. In this study, we induced AKI in macrophage lineage-specific Mafb-deficient mice (C57BL/6J) using the ischemia-reperfusion injury model to analyze these mechanisms. Our results showed that MAFB regulates the expression of Alox15 (arachidonate 15-lipoxygenase) in macrophages during ischemic AKI. The expression of ALOX15 was significantly decreased at the mRNA and protein levels in macrophages that infiltrated the kidneys of macrophage-specific Mafb-deficient mice at 24 h after ischemia-reperfusion injury. ALOX15 promotes the resolution of inflammation under acute conditions by producing specialized proresolving mediators by oxidizing essential fatty acids. Therefore, MAFB in macrophages promotes the resolution of inflammation in ischemic AKI by regulating the expression of Alox15. Moreover, MAFB expression in macrophages is upregulated via the COX-2/PGE2/EP4 pathway in ischemic AKI. Our in vitro assay showed that MAFB regulates the expression of Alox15 under the COX-2/PGE2/EP4 pathway in macrophages. PGE2 mediates the lipid mediator (LM) class switch from inflammatory LMs to specialized proresolving mediators. Therefore, MAFB plays a key role in the PGE2-mediated LM class switch by regulating the expression of Alox15. Our study identified a previously unknown mechanism by which MAFB in macrophages alleviates ischemic AKI and provides new insights into regulating the LM class switch in acute inflammatory conditions.
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Mabalirajan U, Agrawal A, Ghosh B. Comment on "Ym1/2 promotes Th2 cytokine expression by inhibiting 12/15(S)-lipoxygenase: identification of a novel pathway for regulating allergic inflammation". THE JOURNAL OF IMMUNOLOGY 2009; 183:6039; author reply 6039-40. [PMID: 19890062 DOI: 10.4049/jimmunol.0990091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Zhang W, Huang F, Ding X, Qin J, Wang W, Luo L. Identifying ALOX15-initiated lipid peroxidation increases susceptibility to ferroptosis in asthma epithelial cells. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167176. [PMID: 38641013 DOI: 10.1016/j.bbadis.2024.167176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
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.
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Shen N, Li M, Fang B, Li X, Jiang F, Zhu T, Zheng J, Zhang W. ALOX15-Driven Ferroptosis: The key target in Dihydrotanshinone I's epigenetic Battle in hepatic stellate cells against liver fibrosis. Int Immunopharmacol 2025; 146:113827. [PMID: 39675198 DOI: 10.1016/j.intimp.2024.113827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2024] [Revised: 12/02/2024] [Accepted: 12/07/2024] [Indexed: 12/17/2024]
Abstract
BACKGROUND It is known that ferroptosis promotes hepatic stellate cells (HSCs) inactivation. Arachidonate 15-Lipoxygenase (ALOX15), a ferroptosis driver gene, participates in disease progression. PURPOSE Dihydrotanshinone I (DHI), an active compound from Salvia miltiorrhiza, effectively regulates HSC inactivation. Nonetheless, there still needs to be clear understanding of how DHI affects HSC ferroptosis. METHODS This study primarily investigates DHI's protective effects on liver fibrosis in vivo and in vitro. Additionally, we explored the molecular mechanisms by which DHI promotes ferroptosis in HSCs. The relationship between ALOX15 level and methylation was examined. Molecular docking was performed to confirm the targeting between early growth response protein 1 (EGR1) and DHI. RESULTS DHI exhibited a mitigating effect on liver fibrosis in vivo. DHI-induced inactivation of HSC by promoting ferroptosis, accompanied by an elevation in intracellular iron and reactive oxygen species (ROS) levels. Results of transcriptome sequencing and quantitative real-time PCR (qRT-PCR) confirmed the elevation of ALOX15 (a ferroptosis driver gene) in HSCs with DHI. Loss of ALOX15 inhibited DHI-induced ferroptosis. Interestingly, DNA methyltransferase 1 (DNMT1), an essential DNA methyltransferase, was downregulated by DHI. Overexpression of DNMT1 resulted in decreased ALOX15 expression in cells with DHI. Notably, transcription factor EGR1 was demonstrated to regulate DNMT1 expression. EGR1 deficiency led to an increase in DNMT1 expression, which inhibited DHI-induced ferroptosis. Molecular docking confirmed that EGR1 could serve as a direct pharmacological target of DHI. CONCLUSION DHI upregulates EGR1 level, leading to decreased DNMT1 expression and increased ALOX15 demethylation, thereby promoting HSC ferroptosis and inactivation.
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Chen Y, Liu Z, Chen H, Wen Y, Fan L, Luo M. Rhythm gene PER1 mediates ferroptosis and lipid metabolism through SREBF2/ALOX15 axis in polycystic ovary syndrome. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167182. [PMID: 38653359 DOI: 10.1016/j.bbadis.2024.167182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/08/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Abstract
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.
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Oyagbemi AA, Saba AB, Ibraheem AO. Curcumin: from food spice to cancer prevention. Asian Pac J Cancer Prev 2009; 10:963-967. [PMID: 20192567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Curcumin [1, 7-bis (4-hydroxy-3-methoxyphenyl)-1, 6 heptadiene-3, 5-dione] is an orange-yellow component of turmeric (Curcuma longa), a spice often found in curry powder. It is known to have a variety of biologic and pharmacologic activities, including anti-inflammatory, anti-oxidant, and anticarcinogenic potential. It is a potent inhibitor of cytochrome P450 with capacity to simultaneously induce detoxifying enzymes such as glutathione S-transferase and as such may find application as a chemopreventive agent. Curcumin is a potent inhibitor of cyclooxygenase-2, lipooxygenase, ornithine decarboxylase (ODC), nuclear factor-kappaB, c-Jun N-terminal kinase and protein kinase C and has also been demonstrated to play a vital role against pathological conditions such as cancer, atherosclerosis, and neurodegenerative diseases.
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Yang X, Chen H, Shen W, Chen Y, Lin Z, Zhuo J, Wang S, Yang M, Li H, He C, Zhang X, Hu Z, Lian Z, Yang M, Wang R, Li C, Pan B, Xu L, Chen J, Wei X, Wei Q, Xie H, Zheng S, Lu D, Xu X. FGF21 modulates immunometabolic homeostasis via the ALOX15/15-HETE axis in early liver graft injury. Nat Commun 2024; 15:8578. [PMID: 39362839 PMCID: PMC11449914 DOI: 10.1038/s41467-024-52379-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 09/02/2024] [Indexed: 10/05/2024] Open
Abstract
Fibroblast growth factor 21 (FGF21) is essential for modulating hepatic homeostasis, but the impact of FGF21 on liver graft injury remains uncertain. Here, we show that high FGF21 levels in liver graft and serum are associated with improved graft function and survival in liver transplantation (LT) recipients. FGF21 deficiency aggravates early graft injury and activates arachidonic acid metabolism and regional inflammation in male mouse models of hepatic ischemia/reperfusion (I/R) injury and orthotopic LT. Mechanistically, FGF21 deficiency results in abnormal activation of the arachidonate 15-lipoxygenase (ALOX15)/15-hydroxy eicosatetraenoic acid (15-HETE) pathway, which triggers a cascade of innate immunity-dominated pro-inflammatory responses in grafts. Notably, the modulating role of FGF21/ALOX15/15-HETE pathway is more significant in steatotic livers. In contrast, pharmacological administration of recombinant FGF21 effectively protects against hepatic I/R injury. Overall, our study reveals the regulatory mechanism of FGF21 and offers insights into its potential clinical application in early liver graft injury after LT.
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Kirkik D, Kalkanli Tas S. Arachidonate 15-lipoxygenase: A promising therapeutic target for alleviating inflammation in acute pancreatitis. World J Gastroenterol 2025; 31:102752. [PMID: 40309226 PMCID: PMC12038556 DOI: 10.3748/wjg.v31.i15.102752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2024] [Revised: 02/21/2025] [Accepted: 03/07/2025] [Indexed: 04/18/2025] Open
Abstract
This article discusses the significant findings from the study on the transfection of arachidonate 15-lipoxygenase (ALOX15) and its therapeutic potential in managing acute pancreatitis (AP). The research highlights the role of ALOX15 in attenuating inflammatory responses, apoptosis, and autophagy in a cerulein-induced AP murine model. By using a recombinant lentiviral vector for efficient gene delivery, the study provides compelling evidence for the protective effects of ALOX15 transfection on pancreatic tissue. The authors demonstrate that ALOX15 reduces the expression of key inflammatory markers like interleukin-β and tumor necrosis factor α while promoting apoptosis through caspase-3 activation. Furthermore, the modulation of autophagy and structural preservation of pancreatic acinar cells suggest that ALOX15 could be a promising therapeutic target for AP. The implications of these findings are discussed, emphasizing the potential for future clinical translation and further research to explore the molecular mechanisms and therapeutic applications of ALOX15 in inflammatory diseases.
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Oliw EH. Thirty years with three-dimensional structures of lipoxygenases. Arch Biochem Biophys 2024; 752:109874. [PMID: 38145834 DOI: 10.1016/j.abb.2023.109874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/17/2023] [Accepted: 12/17/2023] [Indexed: 12/27/2023]
Abstract
The X-ray crystal structures of soybean lipoxygenase (LOX) and rabbit 15-LOX were reported in the 1990s. Subsequent 3D structures demonstrated a conserved U-like shape of the substrate cavities as reviewed here. The 8-LOX:arachidonic acid (AA) complex showed AA bound to the substrate cavity carboxylate-out with C10 at 3.4 Å from the iron metal center. A recent cryo-electron microscopy (EM) analysis of the 12-LOX:AA complex illustrated AA in the same position as in the 8-LOX:AA complex. The 15- and 12-LOX complexes with isoenzyme-specific inhibitors/substrate mimics confirmed the U-fold. 5-LOX oxidizes AA to leukotriene A4, the first step in biosynthesis of mediators of asthma. The X-ray structure showed that the entrance to the substrate cavity was closed to AA by Phe and Tyr residues of a partly unfolded α2-helix. Recent X-ray analysis revealed that soaking with inhibitors shifted the short α2-helix to a long and continuous, which opened the substrate cavity. The α2-helix also adopted two conformations in 15-LOX. 12-LOX dimers consisted of one closed and one open subunit with an elongated α2-helix. 13C-ENDOR-MD computations of the 9-MnLOX:linoleate complex showed carboxylate-out position with C11 placed 3.4 ± 0.1 Å from the catalytic water. 3D structures have provided a solid ground for future research.
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Han YC, Zhang JC, Zhang CC, DU J. [Arachidonic acid Alox15/12-HETE signaling inhibits vascular calcification]. SHENG LI XUE BAO : [ACTA PHYSIOLOGICA SINICA] 2021; 73:571-576. [PMID: 34405213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This study aims to explore the effects of arachidonic acid lipoxygenase metabolism in vascular calcification. We used 5/6 nephrectomy and high-phosphorus feeding to establish a model of vascular calcification in mice. Six weeks after nephrectomy surgery, vascular calcium content was measured, and Alizarin Red S and Von Kossa staining were applied to detect calcium deposition in aortic arch. Control aortas and calcified aortas were collected for mass spectrometry detection of arachidonic acid metabolites, and active molecules in lipoxygenase pathway were analyzed. Real-time quantitative PCR was used to detect changes in the expression of lipoxygenase in calcified aortas. Lipoxygenase inhibitor was used to clarify the effect of lipoxygenase metabolic pathways on vascular calcification. The results showed that 6 weeks after nephrectomy surgery, the aortic calcium content of the surgery group was significantly higher than that of the sham group (P < 0.05). Alizarin Red S staining and Von Kossa staining showed obvious calcium deposition in aortic arch from surgery group, indicating formation of vascular calcification. Nine arachidonic acid lipoxygenase metabolites were quantitated using liquid chromatography/mass spectrometry (LC-MS) analysis. The content of multiple metabolites (12-HETE, 11-HETE, 15-HETE, etc.) was significantly increased in calcified aortas, and the most abundant and up-regulated metabolite was 12-HETE. Furthermore, we examined the mRNA levels of metabolic enzymes that produce 12-HETE in calcified blood vessels and found the expression of arachidonate lipoxygenase-15 (Alox15) was increased. Blocking Alox15/12-HETE by Alox15 specific inhibitor PD146176 significantly decreased the plasma 12-HETE content, promoted calcium deposition in aortic arch and increased vascular calcium content. These results suggest that the metabolism of arachidonic acid lipoxygenase is activated in calcified aorta, and the Alox15/12-HETE signaling pathway may play a protective role in vascular calcification.
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Zheng ZJ, Zhang HY, Hu YL, Li Y, Wu ZH, Li ZP, Chen DR, Luo Y, Zhang XJ, Li C, Wang XY, Xu D, Qiu W, Li HP, Liao XP, Ren H, Sun J. Sleep Deprivation Induces Gut Damage via Ferroptosis. J Pineal Res 2024; 76:e12987. [PMID: 38975671 DOI: 10.1111/jpi.12987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 06/17/2024] [Accepted: 06/25/2024] [Indexed: 07/09/2024]
Abstract
Sleep deprivation (SD) has been associated with a plethora of severe pathophysiological syndromes, including gut damage, which recently has been elucidated as an outcome of the accumulation of reactive oxygen species (ROS). However, the spatiotemporal analysis conducted in this study has intriguingly shown that specific events cause harmful damage to the gut, particularly to goblet cells, before the accumulation of lethal ROS. Transcriptomic and metabolomic analyses have identified significant enrichment of metabolites related to ferroptosis in mice suffering from SD. Further analysis revealed that melatonin could rescue the ferroptotic damage in mice by suppressing lipid peroxidation associated with ALOX15 signaling. ALOX15 knockout protected the mice from the serious damage caused by SD-associated ferroptosis. These findings suggest that melatonin and ferroptosis could be targets to prevent devastating gut damage in animals exposed to SD. To sum up, this study is the first report that proposes a noncanonical modulation in SD-induced gut damage via ferroptosis with a clearly elucidated mechanism and highlights the active role of melatonin as a potential target to maximally sustain the state during SD.
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Luo L, Liu K, Deng L, Wang W, Lai T, Li X. Chicoric acid acts as an ALOX15 inhibitor to prevent ferroptosis in asthma. Int Immunopharmacol 2024; 142:113187. [PMID: 39298822 DOI: 10.1016/j.intimp.2024.113187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Revised: 08/27/2024] [Accepted: 09/13/2024] [Indexed: 09/22/2024]
Abstract
BACKGROUND Chicoric acid (CA) is a crucial immunologically active compound found in chicory and echinacea, possessing a range of biological activities. Ferroptosis, a type of iron-dependent cell death induced by lipid peroxidation, plays a key role in the development and advancement of asthma. Targeting ferroptosis could be a potential therapeutic strategy for treating asthma. PURPOSE The purpose of this study was to explore the screening of ALOX15, a pivotal target of ferroptosis in asthma, and potential therapeutic agents, as well as to investigate the promising potential of CA as an ALOX15 inhibitor for modulating ferroptosis in asthma. METHODS Through high-throughput data processing of bronchial epithelial RNA from asthma patients using bioinformatics and machine learning, the key target of ferroptosis in asthma, ALOX15, was identified. An inhibitor of ALOX15 was then obtained through high-throughput molecular docking and molecular dynamics simulation tests. In vitro experiments were conducted using a 16HBE cell model induced by house dust mite (HDM) and lipopolysaccharide (LPS), which were treated with the ALOX15 inhibitor (PD146176), CA treatment, or ALOX15 knockdown. In vivo experiments were also carried out using a mouse model induced by HDM and LPS. RESULTS The composite model of ALOX15 and CA in molecular dynamics simulations shows good stability and flexibility. Network pharmacological analysis reveals that CA regulates ferroptosis through ALOX15 in treating asthma. In vitro studies show that ALOX15 is highly expressed in HDM and LPS treatments, while CA inhibits HDM and LPS-induced ferroptosis in 16HBE cells by reducing ALOX15 expression. Knockdown of ALOX15 has the opposite effect. Metabolomics analysis identifies key compounds associated with ferroptosis, including L-Targinine, eicosapentaenoic acid, 16-hydroxy hexadecanoic acid, and succinic acid. In vivo experiments demonstrate that CA suppresses ALOX15 expression, inhibits ferroptosis, and improves asthma symptoms in mice. CONCLUSION Our research initially identified CA as a promising asthma treatment that effectively blocks ferroptosis by specifically targeting ALOX15. This study not only highlights CA as a potential therapeutic agent for asthma but also introduces novel targets and treatment options for this condition, along with innovative approaches for utilizing natural compounds to target diseases associated with ferroptosis.
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