Reaction Process: WikiPathways:WP4348
Eicosanoid metabolism via lipoxygenases (LOX) related metabolites
find 30 related metabolites which is associated with chemical reaction(pathway) Eicosanoid metabolism via lipoxygenases (LOX)
Arachidonic acid ⟶ 12-HETE
Arachidonic acid
Arachidonic acid is a polyunsaturated, essential fatty acid that has a 20-carbon chain as a backbone and four cis-double bonds at the C5, C8, C11, and C14 positions. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is synthesized from dietary linoleic acid. Arachidonic acid mediates inflammation and the functioning of several organs and systems either directly or upon its conversion into eicosanoids. Arachidonic acid in cell membrane phospholipids is the substrate for the synthesis of a range of biologically active compounds (eicosanoids) including prostaglandins, thromboxanes, and leukotrienes. These compounds can act as mediators in their own right and can also act as regulators of other processes, such as platelet aggregation, blood clotting, smooth muscle contraction, leukocyte chemotaxis, inflammatory cytokine production, and immune function. Arachidonic acid can be metabolized by cytochrome p450 (CYP450) enzymes into 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs), their corresponding dihydroxyeicosatrienoic acids (DHETs), and 20-hydroxyeicosatetraenoic acid (20-HETE). The production of kidney CYP450 arachidonic acid metabolites is altered in diabetes, pregnancy, hepatorenal syndrome, and in various models of hypertension, and it is likely that changes in this system contribute to the abnormalities in renal function that are associated with many of these conditions. Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid (PMID: 12736897, 12736897, 12700820, 12570747, 12432908). The beneficial effects of omega-3 fatty acids are believed to be due in part to selective alteration of arachidonate metabolism that involves cyclooxygenase (COX) enzymes (PMID: 23371504). 9-Oxononanoic acid (9-ONA), one of the major products of peroxidized fatty acids, was found to stimulate the activity of phospholipase A2 (PLA2), the key enzyme to initiate the arachidonate cascade and eicosanoid production (PMID: 23704812). Arachidonate lipoxygenase (ALOX) enzymes metabolize arachidonic acid to generate potent inflammatory mediators and play an important role in inflammation-associated diseases (PMID: 23404351). Essential fatty acid. Constituent of many animal phospholipids Arachidonic acid. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=506-32-1 (retrieved 2024-07-15) (CAS RN: 506-32-1). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0). Arachidonic acid is an essential fatty acid and a major constituent of biomembranes. Arachidonic acid is an essential fatty acid and a major constituent of biomembranes.
12(S)-HPETE
12-HPETE is one of the six monohydroperoxy fatty acids produced by the non-enzymatic oxidation of arachidonic acid (Leukotrienes). Reduction of the hydroperoxide yields the more stable hydroxyl fatty acid (+/-)12-HETE. A family of biologically active compounds derived from arachidonic acid by oxidative metabolism through the 5-lipoxygenase pathway. They participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. They have potent actions on many essential organs and systems, including the cardiovascular, pulmonary, and central nervous system as well as the gastrointestinal tract and the immune system. 12-HPETE is one of the six monohydroperoxy fatty acids produced by the non-enzymatic oxidation of arachidonic acid (Leukotrienes). Reduction of the hydroperoxide yields the more stable hydroxyl fatty acid (+/-)12-HETE. D006401 - Hematologic Agents > D010975 - Platelet Aggregation Inhibitors D002317 - Cardiovascular Agents > D014662 - Vasoconstrictor Agents
12-HETE
12-Hydroxyeicosatetraenoic acid (CAS: 71030-37-0), also known as 12-HETE, is an eicosanoid, a 5-lipoxygenase metabolite of arachidonic acid. 5-Lipoxygenase (LO)-derived leukotrienes are involved in inflammatory glomerular injury. LO product 12-HETE is associated with the pathogenesis of hypertension and may mediate angiotensin II and TGFbeta induced mesangial cell abnormality in diabetic nephropathy. 12-HETE is markedly elevated in the psoriatic lesions. 12-HETE is a vasoconstrictor eicosanoid that contributes to high blood pressure in (renovascular) hypertension and pregnancy-induced hypertension. A significant percentage of patients suffering from a selective increase in plasma LDL cholesterol (type IIa hyperlipoproteinemia) exhibits increased platelet reactivity. This includes enhanced platelet responsiveness against a variety of platelet-stimulating agents ex vivo and enhanced arachidonic acid metabolism associated with increased generation of arachidonic acid metabolites such as 12-HETE, and secretion of platelet-storage products (PMID: 7562532, 12480795, 17361113, 8498970, 1333255, 2119633). 12-HETE is a highly selective ligand used to label mu-opioid receptors in both membranes and tissue sections. The 12-S-HETE analog has been reported to augment tumour cell metastatic potential through activation of protein kinase C. 12-HETE has a diversity of biological actions and is generated by a number of tissues including the renal glomerulus and the vasculature. 12-HETE is one of the six monohydroxy fatty acids produced by the non-enzymatic oxidation of arachidonic acid. 12-HETE is a neuromodulator that is synthesized during ischemia. Its neuronal effects include attenuation of calcium influx and glutamate release as well as inhibition of AMPA receptor (AMPA-R) activation. 12-HETE is found to be associated with peroxisomal biogenesis defect and Zellweger syndrome, which are inborn errors of metabolism.
15-HETE
15-HETE is a hydroxyeicosatetraenoic acid. Hydroxyeicosatetraenoic acids (HETEs) are formed by the 5-, 12-, and 15-lipoxygenase (LO) pathways. The 5- and 12-LO products are mainly proinflammatory in the skin whereas the main 15-LO product 15-HETE has antiinflammatory capacities. In vitro, 15-HETE has been shown to inhibit LTB4 formation, 12-HETE formation, and specifically inhibits the neutrophil chemotactic effect of LTB4. The inhibition of LTB4 formation is probably due to modulation of the 5-LO because no changes in PGE2 formation have been determined. In vivo, 15-HETE inhibits LTB4-induced erythema and edema, and reduces LTB4 in the synovial fluid of carragheenan-induced experimental arthritis in dogs. 15-HETE also has some immunomodulatory effects. It inhibits the mixed lymphocyte reaction, induces generation of murine cytotoxic suppressor T cells, and it decreases interferon production by murine lymphoma cells. Furthermore, IL-4 and IL-13 have recently been shown to be potent activators of the 15-LO in mononuclear cells (PMID: 11104340). 15(S)-HETE is found to be associated with Zellweger syndrome, which is an inborn error of metabolism. 15(S)-HETE is a hydroxyeicosatetraenoic acid. Hydroxyeicosatetraenoic acids (HETEs) are formed by the 5-, 12- and 15-lipoxygenase (LO) pathways. 5- and 12-LO products are mainly proinflammatory in the skin whereas the main 15-LO product 15-HETE has antiinflammatory capacities. In vitro 15-HETE has been shown to inhibit LTB4 formation, 12-HETE formation and specifically inhibits the neutrophil chemotactic effect of LTB4. The inhibition of LTB4 formation is probably due to modulation of the 5-LO because no changes in PGE2 formation have been determined. In vivo, 15-HETE inhibits LTB4-induced erythema and edema, and reduces LTB4 in the synovial fluid of carragheenan-induced experimental arthritis in dogs. 15-HETE has also some immunomodulatory effects. It inhibits the mixed lymphocyte reaction, induces generation of murine cytotoxic suppressor T cells, and it decreases interferon production by murine lymphoma cells. Furthermore, IL-4 and IL-13 have recently been shown to be potent activators of the 15-LO in mononuclear cells. (PMID: 11104340) [HMDB] 15(S)-HETE. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=54845-95-3 (retrieved 2024-07-10) (CAS RN: 54845-95-3). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).
15-KETE
15-OxoETE or 15-KETE is a keto-containing leukotriene derivative produced by oxidation of the 15-hydroxyl of 15-HETE. [HMDB] 15-OxoETE or 15-KETE is a keto-containing leukotriene derivative produced by oxidation of the 15-hydroxyl of 15-HETE.
5-KETE
5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE), 5-lipoxygenase product is a potent chemoattractant for neutrophils and eosinophils. Its actions are mediated by the oxoeicosanoid (OXE) receptor, a member of the G protein-coupled receptor family.(PMID:18292294) [HMDB] 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE), 5-lipoxygenase product is a potent chemoattractant for neutrophils and eosinophils. Its actions are mediated by the oxoeicosanoid (OXE) receptor, a member of the G protein-coupled receptor family.(PMID:18292294).
Leukotriene B4
A leukotriene composed of (6Z,8E,10E,14Z)-icosatetraenoic acid having (5S)- and (12R)-hydroxy substituents. It is a lipid mediator of inflammation that is generated from arachidonic acid via the 5-lipoxygenase pathway. Chemical was purchased from CAY20110 (Lot 0439924-0).; Diagnostic ions: 335.1, 317.2, 195.1, 129.0, 115.0, 111.5
Leukotriene C4
Leukotriene C4 (LTC4) is a cysteinyl leukotriene (CysLT), a family of potent inflammatory mediators. Eosinophils, one of the principal cell types recruited to and activated at sites of allergic inflammation, is capable of elaborating lipid mediators, including leukotrienes derived from the oxidative metabolism of arachidonic acid (AA). Potentially activated eosinophils may elaborate greater quantities of LTC4, than normal eosinophils. These activated eosinophils thus are primed for enhanced LTC4 generation in response to subsequent stimuli. Some recognized priming stimuli are chemoattractants (e.g. eotaxin, PAF) that may participate in the recruitment of eosinophils to sites of allergic inflammation. The mechanisms by which chemoattractants and other activating cytokines (e.g. interleukin (IL)-5) or extracellular matrix components (e.g. fibronectin) enhance eosinophil eicosanoid formation are pertinent to the functions of these eicosanoids as paracrine mediators of allergic inflammation. Some eosinophil-derived eicosanoids may be active in down-regulating inflammation. It is increasingly likely that eicosanoids synthesized within cells, including eosinophils, may have intracellular (e.g. intracrine) roles in regulating cell functions, in addition to the more recognized activities of eicosanoids as paracrine mediators of inflammation. Acting extracellularly, the cysteinyl leukotrienes (CysLTs) LTC4 and its extracellular derivatives, LTD4 and LTE4 are key paracrine mediators pertinent to asthma and allergic diseases. Based on their receptor-mediated capabilities, they can elicit bronchoconstriction, mucus hypersecretion, bronchial hyperresponsiveness, increased microvascular permeability, and additional eosinophil infiltration. Eosinophils are a major source of CysLTs and have been identified as the principal LTC4 synthase expressing cells in bronchial mucosal biopsies of asthmatic subjects (PMID: 12895596). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. Leukotriene c4, also known as ltc4 or 5s,6r-ltc(sub 4), is a member of the class of compounds known as oligopeptides. Oligopeptides are organic compounds containing a sequence of between three and ten alpha-amino acids joined by peptide bonds. Thus, leukotriene c4 is considered to be an eicosanoid lipid molecule. Leukotriene c4 is practically insoluble (in water) and a moderately acidic compound (based on its pKa). Leukotriene c4 can be synthesized from icosa-7,9,11,14-tetraenoic acid. Leukotriene c4 is also a parent compound for other transformation products, including but not limited to, leukotriene C4 methyl ester, 11,12-dihydro-(12R)-hydroxyleukotriene C4, and 11,12-dihydro-12-oxoleukotriene C4. Leukotriene c4 can be found in a number of food items such as gram bean, maitake, caraway, and burbot, which makes leukotriene c4 a potential biomarker for the consumption of these food products. Leukotriene c4 can be found primarily in blood and cerebrospinal fluid (CSF), as well as throughout most human tissues. In humans, leukotriene c4 is involved in several metabolic pathways, some of which include trisalicylate-choline action pathway, antipyrine action pathway, nepafenac action pathway, and fenoprofen action pathway. Leukotriene c4 is also involved in a couple of metabolic disorders, which include leukotriene C4 synthesis deficiency and tiaprofenic acid action pathway. Moreover, leukotriene c4 is found to be associated with eczema. Leukotriene C4 (LTC4) is a leukotriene. LTC4 has been extensively studied in the context of allergy and asthma. In cells of myeloid origin such as mast cells, its biosynthesis is orchestrated by translocation to the nuclear envelope along with co-localization of cytosolic phospholipase A2 (cPLA2), Arachidonate 5-lipoxygenase (5-LO), 5-lipoxygenase-activating protein (FLAP) and LTC4 synthase (LTC4S), which couples glutathione to an LTA4 intermediate.The MRP1 transporter then secretes cytosolic LTC4 and cell surface proteases further metabolize it by sequential cleavage of the γ-glutamyl and glycine residues off its glutathione segment, generating the more stable products LTD4 and LTE4. All three leukotrienes then bind at different affinities to two G-protein coupled receptors: CYSLTR1 and CYSLTR2, triggering pulmonary vasoconstriction and bronchoconstriction .
Leukotriene D4
C25H40N2O6S (496.26069400000006)
Leukotriene D4 (LTD4) is a cysteinyl leukotriene. Cysteinyl leukotrienes (CysLTs) are a family of potent inflammatory mediators that appear to contribute to the pathophysiologic features of allergic rhinitis. LTD4 is a pro-inflammatory mediator known to mediate its effects through specific cell-surface receptors belonging to the G-protein-coupled receptor family, namely the high-affinity CysLT1 (cysteinyl leukotriene 1) receptor. LTD4 is present at high levels in many inflammatory conditions, and areas of chronic inflammation have an increased risk for subsequent cancer development. LTD4 is associated with the pathogenesis of several inflammatory disorders, such as asthma and inflammatory bowel disease. Exposure to LTD4 increases survival and proliferation in intestinal epithelial cells. CysLT1 regulator is up-regulated in colon cancer tissue and LTD4 signalling facilitates the survival of cancer cells. LTD4 could reduce apoptosis in non-transformed epithelial cells. LTD4 causes up-regulation of beta-catenin through the CysLT1 receptor, PI3K (phosphoinositide 3-kinase), and GSK-3β (glycogen synthase kinase 3β). LTD4 induces beta-catenin translocation to the nucleus and activation of TCF/LEF family of transcription factors. LTD4 causes accumulation of free beta-catenin in non-transformed intestinal epithelial cells through the CysLT1 receptor, and this accumulation is dependent upon the activation of PI3K as well as GSK-3β inactivation (PMID: 16042577, 12607939). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent and are able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis through receptor-mediated G-protein linked signaling pathways. Leukotriene D4 (LTD4) is a cysteinyl leukotriene a family of potent inflammatory mediators. LTD4 is a pro-inflammatory mediator known to mediate its effects through specific cell-surface receptors belonging to the G-protein-coupled receptor family, namely the high-affinity CysLT1 (cysteinyl leukotriene 1) receptor. LTD4 is present at high levels in many inflammatory conditions, and areas of chronic inflammation have an increased risk for subsequent cancer development; LTD4 is associated with the pathogenesis of several inflammatory disorders, such as asthma and inflammatory bowel disease. Exposure to LTD4 increases survival and proliferation in intestinal epithelial cells. CysLT1 regulator is up-regulated in colon cancer tissue and LTD4 signalling facilitates the survival of cancer cells. LTD4 could reduce apoptosis in non-transformed epithelial cells. LTD4 causes up-regulation of b-catenin through the CysLT1 receptor, PI3K (phosphoinositide 3-kinase) and GSK-3b (glycogen synthase kinase 3b). LTD4 induces b-catenin translocation to the nucleus and activation of TCF/LEF family of transcription factors. LTD4 causes accumulation of free b-catenin in non-transformed intestinal epithelial cells through the CysLT1 receptor, and this accumulation is dependent upon the activation of PI3K as well as GSK-3b inactivation. (PMID: 16042577, 12607939)
Lipoxin A4
Lipoxin A4 (LXA4) was first identified in 1984 by Serhan and colleagues as 5-lipoxygenase interaction product of activated leukocytes. Endogenous transcellular biosynthesis of LXA4 occurs via interaction of leukocytes with epithelium, endothelium or platelets. Lipoxins (LXs) or the lipoxygenase interaction products are generated from arachidonic acid via sequential actions of lipoxygenases and subsequent reactions to give specific trihydroxytetraene-containing eicosanoids. These unique structures are formed during cell-cell interactions and appear to act at both temporal and spatially distinct sites from other eicosanoids produced during the course of inflammatory responses and to stimulate natural resolution. Lipoxin A4 (LXA4) and lipoxin B4 (LXB4) are positional isomers that each possesses potent cellular and in vivo actions. These LX structures are conserved across species. The results of numerous studies reviewed in this work now confirm that they are the first recognized eicosanoid chemical mediators that display both potent anti-inflammatory and pro-resolving actions in vivo in disease models that include rabbit, rat, and mouse systems. LXs act at specific GPCRs as agonists to regulate cellular responses of interest in inflammation and resolution. Aspirin has a direct impact in the LX circuit by triggering the biosynthesis of endogenous epimers of LX, termed the aspirin-triggered 15-epi-LX, that share the potent anti-inflammatory actions of LX. (PMID: 16005201, 16613568). Lipoxin A4 (LXA4) was first identified in 1984 by Serhan and colleagues as 5-lipoxygenase interaction product of activated leukocytes. Endogenous transcellular biosynthesis of LXA4 occurs via interaction of leukocytes with epithelium, endothelium or platelets. D018373 - Peripheral Nervous System Agents > D018689 - Sensory System Agents D002491 - Central Nervous System Agents > D000700 - Analgesics D000893 - Anti-Inflammatory Agents D018501 - Antirheumatic Agents
5(S)-Hydroperoxyeicosatetraenoic acid
5(S)-Hydroperoxyeicosatetraenoic acid is a lipid hydroperoxide precursor of leukotrienes. The first step of biosynthesis of leukotrienes is conversion of arachidonic acid into 5(S)-hydroperoxy-6,8,11,14-(E,Z,Z,Z)-eicosatetraenoic acid [5(S)-HpETE] by 5- lipoxygenases (5-LOX). Lipid hydroperoxides undergo homolytic decomposition into bifunctional electrophiles, which react with DNA bases to form DNA adducts. These DNA modifications are proposed to be involved in the etiology of cancer, cardiovascular disease, and neurodegeneration. 5-LOX, the enzyme responsible for the formation of 5(S)-HpETE in vivo, is expressed primarily in leukocytes, including monocytes and macrophages. Studies have implicated the 5-LOX pathway as an important mediator in the pathology of atherosclerosis. (PMID: 15777099). Endogenously generated 5-hydroperoxyeicosatetraenoic acid is the preferred substrate for human leukocyte leukotriene A4 synthase activity. Thus, the arachidonic acid moiety is preferentially converted to LTA4 in a concerted reaction without dissociation of a 5-HPETE intermediate. (PMID: 3036580). 5(S)-Hydroperoxyeicosatetraenoic acid is a lipid hydroperoxide precursor of leukotrienes. The first step of biosynthesis of leukotrienes is conversion of arachidonic acid into 5(S)-hydroperoxy-6,8,11,14-(E,Z,Z,Z)-eicosatetraenoic acid [5(S)-HpETE] by 5- lipoxygenases (5-LOX). Lipid hydroperoxides undergo homolytic decomposition into bifunctional electrophiles, which react with DNA bases to form DNA adducts. These DNA modifications are proposed to be involved in the etiology of cancer, cardiovascular disease, and neurodegeneration.
Leukotriene A4
Leukotriene A4 (LTA4) is the first metabolite in the series of reactions leading to the synthesis of all leukotrienes. 5-Lipoxygenase (5-LO) catalyzes the two-step conversion of arachidonic acid to LTA4.The first step consists of the oxidation of arachidonic acid to the unstable intermediate 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and the second step is the dehydration of 5-HPETE to form LTA4. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. (PMID: 10591081, 2820055). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. Leukotriene A4 (LTA4) is the first metabolite in the series of reactions leading to the synthesis of all leukotrienes. 5-Lipoxygenase (5-LO) catalyzes the two-step conversion of arachidonic acid to LTA4.The first step consists of the oxidation of arachidonic acid to the unstable intermediate 5-hydroperoxyeicosatetraenoic acid (5-HPETE), and the second step is the dehydration of 5-HPETE to form LTA4. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. (PMID: 10591081, 2820055)
12-Keto-leukotriene B4
12-Keto-leukotriene B4 is formed when leukotriene B4 (LTB4) is metabolized by beta-oxidation. LTB4 is the major metabolite in neutrophil polymorphonuclear leukocytes. Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region and phosphorylation to either enhance or inhibit the activity of 5-LO. Biologically active LTB4 is metabolized by w-oxidation carried out by specific cytochrome P450s (CYP4F) followed by beta-oxidation from the w-carboxy position and after CoA ester formation. (PMID: 8632343, 9667737)Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. 12-Keto-leukotriene B4 is formed when leukotriene B4 (LTB4) is metabolized by beta-oxidation. LTB4 is the major metabolite in neutrophil polymorphonuclear leukocytes. Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region and phosphorylation to either enhance or inhibit the activity of 5-LO. Biologically active LTB4 is metabolized by w-oxidation carried out by specific cytochrome P450s (CYP4F) followed by beta-oxidation from the w-carboxy position and after CoA ester formation. (PMID: 8632343, 9667737)
20-Carboxy-leukotriene B4
20-Carboxyleukotriene B4 is an omega-oxidized metabolite of leukotriene B4 (LTB4). Neutrophil microsomes are known to oxidize 20-hydroxy-LTB4 (20-OH-LTB4) to its 20-oxo and 20-carboxy derivatives in the presence of NADPH. This activity has been ascribed to LTB4 omega-hydroxylase (cytochrome P-450LTB omega). Leukotriene B4 release from polymorphonuclear granulocytes of severely burned patients was reduced as compared to healthy donor cells. This decrease is due to an enhanced conversion of LTB4 into the 20-hydroxy- and 20-carboxy-metabolites and further to a decreased LTB4-synthesis. LTB4 is the major metabolite in neutrophil polymorphonuclear leukocytes. Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region and phosphorylation to either enhance or inhibit the activity of 5-LO. Biologically active LTB4 is metabolized by w-oxidation carried out by specific cytochrome P450s (CYP4F) followed by beta-oxidation from the w-carboxy position and after CoA ester formation. Other specific pathways of leukotriene metabolism include the 12-hydroxydehydrogenase/ 15-oxo-prostaglandin-13-reductase that form a series of conjugated diene metabolites that have been observed to be excreted into human urine. Metabolism of LTC4 occurs by sequential peptide cleavage reactions involving a gamma-glutamyl transpeptidase that forms LTD4 (leukotriene D4) and a membrane-bound dipeptidase that converts LTD4 into LTE4 (leukotriene E4) before w-oxidation. These metabolic transformations of the primary leukotrienes are critical for termination of their biological activity, and defects in expression of participating enzymes may be involved in specific genetic disease. (PMID 17623009, 7633595, 2155225, 3039534)Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways.
Leukotriene E4
C23H37NO5S (439.23923120000006)
Leukotriene E4 (LTE4) is a cysteinyl leukotriene. Cysteinyl leukotrienes (CysLTs) are a family of potent inflammatory mediators that appear to contribute to the pathophysiologic features of allergic rhinitis. Nasal blockage induced by CysLTs is mainly due to dilatation of nasal blood vessels, which can be induced by the nitric oxide produced through CysLT1 receptor activation. LTE4 activates contractile and inflammatory processes via specific interaction with putative seven transmembrane-spanning receptors that couple to G proteins and subsequent intracellular signaling pathways. LTE4 is metabolized from leukotriene C4 in a reaction catalyzed by gamma-glutamyl transpeptidase and a particulate dipeptidase from kidney (PMID: 12607939, 12432945, 6311078). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent and are able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis through receptor-mediated G-protein linked signaling pathways. Leukotriene E4 (LTE4) is a cysteinyl leukotriene. Cysteinyl leukotrienes (CysLTs) are a family of potent inflammatory mediators that appear to contribute to the pathophysiologic features of allergic rhinitis. Nasal blockage induced by CysLTs is mainly due to dilatation of nasal blood vessels, which can be induced by the nitric oxide produced through CysLT1 receptor activation. LTE4, activate contractile and inflammatory processes via specific interaction with putative seven transmembrane-spanning receptors that couple to G proteins and subsequent intracellular signaling pathways. LTE4 is metabolized from leukotriene C4 in a reaction catalyzed by gamma-glutamyl transpeptidase and a particulate dipeptidase from kidney. (PMID: 12607939, 12432945, 6311078)
15(S)-HPETE
15(S)-hydroperoxyeicosatetraenoic acid (15(S)-HPETE) is the corresponding hydroperoxide of 15(S)-HETE and undergoes homolytic decomposition to the DNA-reactive bifunctional electrophile 4-oxo-2(E)-nonenal, a precursor of heptanone-etheno-2-deoxyguanosine. Reactive oxygen species convert the omega-6 polyunsaturated fatty acid arachidonic acid into (15-HPETE); vitamin C mediates 15(S)-HPETE decomposition. 15(S)-HPETE initiates apoptosis in vascular smooth muscle cells. 15(S)-HPETE is a lipoxygenase metabolite that affects the expression of cell adhesion molecules (CAMs) involved in the adhesion of leukocytes and/or the accumulation of leukocytes in the vascular endothelium, these being the initial events in endothelial cell injury. 15(S)-HPETE induces a loss of cardiomyocytes membrane integrity. 15-(S)HPETE is a hydroperoxide that enhances the activity of the enzymes lipoxygenase [EC 1.13.11.12] and Na+, K+-ATPase [EC 3.6.3.9] of brain microvessels. Lipoxygenase(s) and Na+-K+-ATPase of brain microvessels may play a significant role in the occurrence of ischemic brain edema. (PMID: 15964853, 15723435, 8655602, 8595608, 2662983). D002317 - Cardiovascular Agents > D014662 - Vasoconstrictor Agents D004791 - Enzyme Inhibitors > D016859 - Lipoxygenase Inhibitors D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides
Troxilin B3
Troxilin B3 is the enzymatically formed derivative of Hepoxilin B3. Normal human epidermis incubated with exogenous AA produces 12-oxo-eicosatetraenoic acid (12-oxo-ETE), hepoxilin A3 (HxA3), and hepoxilin B3 (HxB3) through the 12- Lipoxygenase (LO) pathway. 12-LO is the major arachidonic acid (AA) oxygenation pathway in epidermal cells with total product formation generally exceeding cyclooxygenase activity. Platelet-type 12-LO has been found to be the predominant isoenzyme expressed in human and murine skin epidermis. Increased levels of nonesterified hepoxilins and trioxilins occur in the psoriatic scales. Normal human epidermis synthesized only one of the two possible 10-hydroxy epimers of HxB3 whose formation is probably catalyzed by 12-LO. Hepoxilins exert action on plasma permeability on skin, and induce a specific-receptor-dependent Ca2+ mobilization from endogenous sources and the release of AA and diacylglycerols. (PMID: 11851887) [HMDB] Troxilin B3 is the enzymatically formed derivative of Hepoxilin B3. Normal human epidermis incubated with exogenous AA produces 12-oxo-eicosatetraenoic acid (12-oxo-ETE), hepoxilin A3 (HxA3), and hepoxilin B3 (HxB3) through the 12- Lipoxygenase (LO) pathway. 12-LO is the major arachidonic acid (AA) oxygenation pathway in epidermal cells with total product formation generally exceeding cyclooxygenase activity. Platelet-type 12-LO has been found to be the predominant isoenzyme expressed in human and murine skin epidermis. Increased levels of nonesterified hepoxilins and trioxilins occur in the psoriatic scales. Normal human epidermis synthesized only one of the two possible 10-hydroxy epimers of HxB3 whose formation is probably catalyzed by 12-LO. Hepoxilins exert action on plasma permeability on skin, and induce a specific-receptor-dependent Ca2+ mobilization from endogenous sources and the release of AA and diacylglycerols. (PMID: 11851887).
Trioxilin A3
Trioxilin A3 is the enzymatically formed derivative of Hepoxilin A3. Normal human epidermis incubated with exogenous AA produces 12-oxo-eicosatetraenoic acid (12-oxo-ETE), hepoxilin A3 (HxA3), and hepoxilin B3 (HxB3) through the 12- Lipoxygenase (LO) pathway. 12-LO is the major arachidonic acid (AA) oxygenation pathway in epidermal cells with total product formation generally exceeding cyclooxygenase activity. Platelet-type 12-LO has been found to be the predominant isoenzyme expressed in human and murine skin epidermis. Increased levels of nonesterified hepoxilins and trioxilins occur in the psoriatic scales. Normal human epidermis synthesized only one of the two possible 10-hydroxy epimers of HxB3 whose formation is probably catalyzed by 12-LO. Hepoxilins exert action on plasma permeability on skin, and induce a specific-receptor-dependent Ca2+ mobilization from endogenous sources and the release of AA and diacylglycerols. (PMID: 11851887) [HMDB] Trioxilin A3 is the enzymatically formed derivative of Hepoxilin A3. Normal human epidermis incubated with exogenous AA produces 12-oxo-eicosatetraenoic acid (12-oxo-ETE), hepoxilin A3 (HxA3), and hepoxilin B3 (HxB3) through the 12- Lipoxygenase (LO) pathway. 12-LO is the major arachidonic acid (AA) oxygenation pathway in epidermal cells with total product formation generally exceeding cyclooxygenase activity. Platelet-type 12-LO has been found to be the predominant isoenzyme expressed in human and murine skin epidermis. Increased levels of nonesterified hepoxilins and trioxilins occur in the psoriatic scales. Normal human epidermis synthesized only one of the two possible 10-hydroxy epimers of HxB3 whose formation is probably catalyzed by 12-LO. Hepoxilins exert action on plasma permeability on skin, and induce a specific-receptor-dependent Ca2+ mobilization from endogenous sources and the release of AA and diacylglycerols. (PMID: 11851887).
8(S)-HPETE
8S-HPETE is metabolized from arachidonic acid by the enzyme 8S-lipoxygenase (8-LOX in mouse, ALOX15 and ALOX15B in human). 8S-HPETE will be readily reduced under physiological circumstances to 8S-hydroxyeicosatetraenoic acid (8S-HETE), a natural agonist of peroxisome proliferator-activated receptor alpha (PPAR alpha). (PMID: 16112079) [HMDB] 8S-HPETE is metabolized from arachidonic acid by the enzyme 8S-lipoxygenase (8-LOX in mouse, ALOX15 and ALOX15B in human). 8S-HPETE will be readily reduced under physiological circumstances to 8S-hydroxyeicosatetraenoic acid (8S-HETE), a natural agonist of peroxisome proliferator-activated receptor alpha (PPAR alpha). (PMID: 16112079).
12-KETE
12-keto-eicosatetraenoic acid is a biologically active eicosanoid in the nervous system of Aplysia.It is a metabolite of 12-HPETE formed by Aplysia nervous tissue. 12-KETE was identified in incubations of the tissue with arachidonic acid using HPLC, UV spectrometry, and gas-chromatography/mass spectrometry. [3H]12-KETE is formed from endogenous lipid stores in nervous tissue, labeled with [3H]arachidonic acid upon stimulation by application of histamine. In L14 and L10 cells, identified neurons in the abdominal ganglion, applications of 12-KETE elicit changes in membrane potential similar to those evoked by histamine.[PMID:2774398] [HMDB] 12-keto-eicosatetraenoic acid is a biologically active eicosanoid in the nervous system of Aplysia.It is a metabolite of 12-HPETE formed by Aplysia nervous tissue. 12-KETE was identified in incubations of the tissue with arachidonic acid using HPLC, UV spectrometry, and gas-chromatography/mass spectrometry. [3H]12-KETE is formed from endogenous lipid stores in nervous tissue, labeled with [3H]arachidonic acid upon stimulation by application of histamine. In L14 and L10 cells, identified neurons in the abdominal ganglion, applications of 12-KETE elicit changes in membrane potential similar to those evoked by histamine.[PMID:2774398].
11-trans-Leukotriene C4
11-trans-Leukotriene C4 (11-trans-LTC4) is a leukotriene derivative formed by the metabolism of LTA4 and is found in human endothelial cells. Leukotrienes (LT) are a family of naturally occurring lipids that are oxygenated metabolites of arachidonic acid. Biosynthesis of the leukotrienes involves the action of a lipoxygenase on arachidonate to yield a hydroperoxy intermediate which is then dehydrated to the allylic epoxide, LTA4. LTA4 can be hydrolyzed to the dihydroxy acid, LTB4 or it can be conjugated with glutathione (GSH) to produce the parent slow reacting substance, LTC4. The leukotrienes are mediators of inflammation, hypersensitivity reactions, and respiratory disorders. On a cellular level, LTC4 and its metabolites, LTD4 and LTE4, are potent constrictors of vascular bronchial smooth muscle. LTC4 and LTD4 also induce plasma leakage from the microvasculature. LTB4 is a potent polymorphonuclear leukocyte (PMNL) chemotaxin and induces neutrophils to degranulate, generate superoxide, and adhere to vascular endothelium. Several investigations of leukotriene synthesis by blood vessels and cultured vascular cells have been undertaken. Vascular preparations have been shown to produce LTB4 and LTC4 and to metabolize LTC4 to LTD4 and LTE4. In addition, mast cells, macrophages, and PMNL, all of which may contaminate whole vessel preparations, are known to synthesize both peptide-containing and dihydroxy acid leukotrienes. Consequently, it is unclear what cells are contributing to vascular leukotriene synthesis. No evidence of isolated vascular cell leukotriene synthesis is currently available. Indeed, this report and others have been unable to detect endothelial cell conversion of arachidonic acid to the leukotrienes. The fact that vascular endothelium lacks the full complement of leukotriene biosynthetic enzymes does not preclude an active role for this tissue in leukotriene metabolism. In some cases, tissues which are not known to synthesize leukotrienes from arachidonate are able to catalyze one or more of the intermediate steps of the pathway. In the present investigation, the leukotriene metabolism of porcine aortic endothelium has been studied. Evidence is presented which indicates that endothelial cells are unable to convert arachidonic acid to LTC4 but, nevertheless, contain LTC4 synthetase. Additional experiments suggest that a neutrophil-endothelial cell interaction augments vascular LTC4 synthesis by the intercellular transfer of LTA4 from PMNL to endothelial cells (PMID: 3023351). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. 11-trans-Leukotriene C4 (11-trans-LTC4) is leukotriene derivative formed by the metabolism of LTA4 and is found in human endothelial cells. Leukotrienes (LT) are a family of naturally occurring lipids that are oxygenated metabolites of arachidonic acid. Biosynthesis of the leukotrienes involves the action of a lipoxygenase on arachidonate to yield a hydroperoxy intermediate which is then dehydrated to the allylic epoxide, LTA4. LTA4 can be hydrolyzed to the dihydroxy acid, LTB4 or it can be conjugated with glutathione (GSH) to produce the parent slow reacting substance, LTC4. The leukotrienes are mediators of inflammation, hypersensitivy reactions, and respiratory disorders. On a cellular level, LTC4 and its metabolites, LTD4 and LTE4, are potent constrictors of vascular bronchial smooth muscle. LTC4 and LTD4 also induce plasma leakage from the microvasculature. LTB4 is a potent polymorphonuclear leukocyte (PMNL) chemotaxin and induces neutrophils to degranulate, generate superoxide, and adhere to vascular endothelium. Several investigations of leukotriene synthesis by blood vessels and cultured vascular cells have been undertaken. Vascular preparations have been shown to produce LTB4 and LTC4 and to metabolize LTC4 to LTD4 and LTE4. In addition, mast cells, macrophages, and PMNL, all of which may contaminate whole vessel preparations, are known to synthesize both peptide-containing and dihydroxy acid leukotrienes. Consequently, it is unclear what cells are contributing to vascular leukotriene synthesis. No evidence of isolated vascular cell leukotriene synthesis is currently available. Indeed, this report and others have been unable to detect endothelial cell conversion of arachidonic acid to the leukotrienes. The fact that vascular endothelium lacks the full complement of leukotriene biosynthetic enzymes does not preclude an active role for this tissue in leukotriene metabolism. In some cases, tissues which are not known to synthesize leukotrienes from arachidonate are able to catalyze one or more of the intermediate steps of the pathway. In the present investigation, the leukotriene metabolism of porcine aortic endothelium has been studied. Evidence is presented which indicates that endothelial cells are unable to convert arachidonic acid to LTC4 but, nevertheless, contain LTC4 synthetase. Additional experiments suggest that a neutrophil- endothelial cell interaction augments vascular LTC4 synthesis by the intercellular transfer of LTA4 from PMNL to endothelial cells. (PMID 3023351)
20-oxo-leukotriene B4
20-oxo-leukotriene B4 is the metabolite of lipid omega-oxidation of leukotriene B4 (LTB4). LTB4 is the major metabolite in neutrophil polymorphonuclear leukocytes. Omega-oxidation is the major pathway for the catabolism of leukotriene B4 in human polymorphonuclear leukocytes. Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region, and phosphorylation to either enhance or inhibit the activity of 5-LO. Biologically active LTB4 is metabolized by omega-oxidation carried out by specific cytochrome P450s (CYP4F) followed by beta-oxidation from the omega-carboxy position and after CoA ester formation (PMID: 7649996, 17623009, 2853166, 6088485). Leukotrienes are eicosanoids. The eicosanoids consist of the prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and lipoxins (LXs). The PGs and TXs are collectively identified as prostanoids. Prostaglandins were originally shown to be synthesized in the prostate gland, thromboxanes from platelets (thrombocytes), and leukotrienes from leukocytes, hence the derivation of their names. All mammalian cells except erythrocytes synthesize eicosanoids. These molecules are extremely potent, able to cause profound physiological effects at very dilute concentrations. All eicosanoids function locally at the site of synthesis, through receptor-mediated G-protein linked signalling pathways. 20-oxo-leukotriene B4 is the metabolite of lipid omega-oxidation of leukotriene B4 (LTB4). LTB4 is the major metabolite in neutrophil polymorphonuclear leukocytes. Omega-oxidation is the major pathway for the catabolism of leukotriene B4 in human polymorphonuclear leukocytes. Leukotrienes are metabolites of arachidonic acid derived from the action of 5-LO (5-lipoxygenase). The immediate product of 5-LO is LTA4 (leukotriene A4), which is enzymatically converted into either LTB4 (leukotriene B4) by LTA4 hydrolase or LTC4 (leukotriene C4) by LTC4 synthase. The regulation of leukotriene production occurs at various levels, including expression of 5-LO, translocation of 5-LO to the perinuclear region and phosphorylation to either enhance or inhibit the activity of 5-LO. Biologically active LTB4 is metabolized by w-oxidation carried out by specific cytochrome P450s (CYP4F) followed by beta-oxidation from the w-carboxy position and after CoA ester formation. (PMID: 7649996, 17623009, 2853166, 6088485)
11-trans-LTE4
C23H37NO5S (439.23923120000006)
11-trans-LTE4 is also known as 11-trans-Leukotriene e4 or 11t-LTE4. 11-trans-LTE4 is considered to be practically insoluble (in water) and acidic. 11-trans-LTE4 is an eicosanoid lipid molecule
15-oxo-5S,6R-dihydroxy-7E,9E,11Z-eicosatrienoic acid
15-oxo-5S,6R-dihydroxy-7E,9E,11Z-eicosatrienoic acid is also known as 13,14-dihydro-15-keto-Lipoxin a4 or DHK-LXA4. 15-oxo-5S,6R-dihydroxy-7E,9E,11Z-eicosatrienoic acid is considered to be practically insoluble (in water) and acidic. 15-oxo-5S,6R-dihydroxy-7E,9E,11Z-eicosatrienoic acid is an eicosanoid lipid molecule
11-trans-LTD4
C25H40N2O6S (496.26069400000006)
5-Hete
A HETE having a 5-hydroxy group and (6E)-, (8Z)-, (11Z)- and (14Z)-double bonds. A HETE having a (5S)-hydroxy group and (6E)-, (8Z)-, (11Z)- and (14Z)-double bonds.
Eoxin A4
An oxylipin that is the (14S,15S)-epoxy derivative of (5Z,8Z,10E,12E)-icosa-5,8,10,12-tetraenoic acid.