Classification Term: 1808
Hepoxilins (ontology term: CHEMONTID:0001020)
Eicosanoids containing an oxirane group attached to the fatty acyl chain." []
found 8 associated metabolites at category metabolite taxonomy ontology rank level.
Ancestor: Eicosanoids
Child Taxonomies: There is no child term of current ontology term.
11,12-Epoxyeicosatrienoic acid
11,12-Epoxyeicosatrienoic acid (CAS: 81276-02-0) is an epoxyeicosatrienoic acid (EET). Induction of CYP2C8 in native coronary artery endothelial cells by beta-naphthoflavone enhances the formation of 11,12-epoxyeicosatrienoic acid, as well as endothelium-derived hyperpolarizing factor-mediated hyperpolarization and relaxation. Transfection of coronary arteries with CYP2C8 antisense oligonucleotides resulted in decreased levels of CYP2C and attenuated the endothelium-derived hyperpolarizing factor-mediated vascular responses. Thus, a CYP-epoxygenase product is an essential component of the endothelium-derived hyperpolarizing factor-mediated relaxation in the porcine coronary artery, and CYP2C8 fulfills the criteria for the coronary endothelium-derived hyperpolarization factor synthase. The role of EETs in the regulation of the cerebral circulation has become more important since it was realized that EETs are produced in another specialized cell type of the brain, the astrocytes. It has become evident that EETs released from astrocytes may mediate cerebral functional hyperemia. Molecular and pharmacological evidence has shown that neurotransmitter release and spillover onto astrocytes can generate EETs. Since these EETs may reach the vasculature via astrocyte foot-processes, they have the same potential as their endothelial counterparts to hyperpolarize and dilate cerebral vessels. P450 enzymes contain heme in their catalytic domain and nitric oxide (NO) appears to bind to these heme moieties and block formation of P450 products, including EETs. Thus, there appears to be crosstalk between P450 enzymes and NO/NO synthase. The role of fatty acid metabolites and cerebral blood flow becomes even more complex in light of data demonstrating that cyclooxygenase products can act as substrates for P450 enzymes (PMID: 17494091, 17434916, 17406062, 17361113, 15581597, 11413051, 10519554). EETs function as autocrine and paracrine mediators. During inflammation, a large amount of arachidonic acid (AA) is released into the cellular milieu and cyclooxygenase enzymes convert this AA to prostaglandins that in turn sensitize pain pathways. However, AA is also converted into natural EETs by cytochrome P450 enzymes. Cytochrome P450 (CYP) epoxygenases convert arachidonic acid into four epoxyeicosatrienoic acid (EET) regioisomers, 5,6-, 8,9-, 11,12-, and 14,15-EET. EETs produce vascular relaxation by activating smooth muscle large-conductance Ca2+-activated K+ channels. In particular, 11,12-epoxy-5Z,8Z,14Z-eicosatrienoic acid has been shown to play a role in the recovery of depleted Ca2+ pools in cultured smooth muscle cells (PMID: 9368016). In addition, EETs have anti-inflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and the brain. EET levels are typically regulated by soluble epoxide hydrolase (sEH), the major enzyme degrading EETs. Specifically, soluble epoxide hydrolase (sEH) converts EETs into dihydroxyeicosatrienoic acids. 11,12-EpETrE or 11,12-epoxy-5Z,8Z,14Z-eicosatrienoic acid is an epoxyeicosatrienoic acid or an EET derived from arachadonic acid. EETs function as autacrine and paracrine mediators. During inflammation, a large amount of arachidonic acid (AA) is released into the cellular milieu and cyclooxygenase enzymes convert this AA to prostaglandins that in turn sensitize pain pathways. However, AA is also converted to natural epoxyeicosatrienoic acids (EETs) by cytochrome P450 enzymes. Cytochrome P450 (CYP) epoxygenases convert arachidonic acid to four epoxyeicosatrienoic acid (EET) regioisomers, 5,6-, 8,9-, 11,12-, and 14,15-EET. EETs produce vascular relaxation by activating smooth muscle large-conductance Ca2+-activated K+ channels. In particular, 11,12-epoxy-5Z,8Z,14Z-eicosatrienoic acid has been show to play a role in the recovery of depleted Ca2+ pools in cultured smooth muscle cells (PMID: 9368016). In addition, EETs have antiinflammatory effects on blood vessels and in the kidney, promote angiogenesis, and protect ischemic myocardium and brain. EET levels are typically regulated by soluble epoxide hydrolase (sEH), the major enzyme degrading EETs. Specifically, soluble epoxide hydrolase (sEH) converts EETs to dihydroxyeicosatrienoic acids. [HMDB] D002317 - Cardiovascular Agents > D014665 - Vasodilator Agents
(5Z,9E,14Z)-(8xi,11R,12S)-11,12-epoxy-8-hydroxyicosa-5,9,14-trienoic Acid
(5Z,9E,14Z)-(8xi,11R,12S)-11,12-epoxy-8-hydroxyicosa-5,9,14-trienoic Acid, also known as Hepoxilin a3 or 8-EH-2, is classified as a member of the Hepoxilins. Hepoxilins are eicosanoids containing an oxirane group attached to the fatty acyl chain. (5Z,9E,14Z)-(8xi,11R,12S)-11,12-epoxy-8-hydroxyicosa-5,9,14-trienoic Acid is considered to be practically insoluble (in water) and acidic
Hepoxilin B3
Hepoxilin B3 is a normal human epidermis eicosanoid. Hepoxilin B3 is dramatically elevated in psoriatic lesions. The primary biological action of the hepoxilins appears to relate to their ability to release calcium from intracellular stores through a receptor-mediated action. The receptor is intracellular, and appears to be G-protein coupled. The conversion of hepoxilin into its omega-hydroxy catabolite has recently been demonstrated through the action of an omega-hydroxylase. This enzyme is different from that which oxidizes leukotriene B4, as the former activity is lost when the cell is disrupted, while leukotriene B4-catabolic activity is recovered in both the intact and disrupted cell. Additionally, hepoxilin catabolism is inhibited by CCCP, a mitochondrial uncoupler, while leukotriene catabolism is unaffected. As hepoxilins cause the translocation of calcium from intracellular stores in the endoplasmic reticulum to the mitochondria, it is speculated that hepoxilin omega-oxidation takes place in the mitochondria, and the omega-oxidation product facilitates accumulation of the elevated cytosolic calcium by the mitochondria. (PMID 10692117, 11851887, 10086189) [HMDB] Hepoxilin B3 is a normal human epidermis eicosanoid. Hepoxilin B3 is dramatically elevated in psoriatic lesions. The primary biological action of the hepoxilins appears to relate to their ability to release calcium from intracellular stores through a receptor-mediated action. The receptor is intracellular, and appears to be G-protein coupled. The conversion of hepoxilin into its omega-hydroxy catabolite has recently been demonstrated through the action of an omega-hydroxylase. This enzyme is different from that which oxidizes leukotriene B4, as the former activity is lost when the cell is disrupted, while leukotriene B4-catabolic activity is recovered in both the intact and disrupted cell. Additionally, hepoxilin catabolism is inhibited by CCCP, a mitochondrial uncoupler, while leukotriene catabolism is unaffected. As hepoxilins cause the translocation of calcium from intracellular stores in the endoplasmic reticulum to the mitochondria, it is speculated that hepoxilin omega-oxidation takes place in the mitochondria, and the omega-oxidation product facilitates accumulation of the elevated cytosolic calcium by the mitochondria. (PMID 10692117, 11851887, 10086189).
Hepoxilin A3
Hepoxilin A3 is an electrophilic eicosanoids synthesized during arachidonic acid oxidative metabolism, which can participate in the Michael addition reaction with glutathione (GSH, a major cellular antioxidant) catalyzed by the GSH-S-transferase (GST) family. GSH-adducts have been observed with molecules synthesized through the 12-lipoxygenase pathway. (PMID 12432937). Hepoxilins have biological actions that appear to have, as their basis, changes in intracellular concentrations of ions including calcium and potassium ions as well as changes in second messenger systems. Recent evidence suggests that the biological actions of the hepoxilins may be receptor-mediated as indicated from data showing the existence of hepoxilin-specific binding proteins in the human neutrophils. Such evidence also implicates the association of G-proteins both in hepoxilin-binding as well as in hepoxilin action. (PMID 7947989). Hepoxilin A3 is an electrophilic eicosanoids synthesized during arachidonic acid oxidative metabolism, which can participate in the Michael addition reaction with glutathione (GSH, a major cellular antioxidant) catalyzed by the GSH-S-transferase (GST) family. GSH-adducts have been observed with molecules synthesized through the 12-lipoxygenase pathway. (PMID 12432937)
10-hydroxy-11S,12S-epoxy-5Z,8Z,14Z-eicosatrienoic acid
10-hydroxy-11S,12S-epoxy-5Z,8Z,14Z-eicosatrienoic acid, also known as Hepoxilin b3 or EPHETA, is classified as a member of the Hepoxilins. Hepoxilins are eicosanoids containing an oxirane group attached to the fatty acyl chain. 10-hydroxy-11S,12S-epoxy-5Z,8Z,14Z-eicosatrienoic acid is considered to be practically insoluble (in water) and acidic
(5Z,8Z)-10-[(2S,3R)-3-[(2Z)-Oct-2-en-1-yl]oxiran-2-yl]deca-5,8-dienoylcarnitine
C27H45NO5 (463.32975600000003)
(5Z,8Z)-10-[(2S,3R)-3-[(2Z)-oct-2-en-1-yl]oxiran-2-yl]deca-5,8-dienoylcarnitine is an acylcarnitine. More specifically, it is an (5Z,8Z)-10-[(2S,3R)-3-[(2Z)-oct-2-en-1-yl]oxiran-2-yl]deca-5,8-dienoic acid ester of carnitine. Acylcarnitines were first discovered more than 70 year ago (PMID: 13825279). It is believed that there are more than 1000 types of acylcarnitines in the human body. The general role of acylcarnitines is to transport acyl-groups (organic acids and fatty acids) from the cytoplasm into the mitochondria so that they can be broken down to produce energy. This process is known as beta-oxidation. According to a recent review [Dambrova et al. 2021, Physiological Reviews], acylcarnitines (ACs) can be classified into 9 different categories depending on the type and size of their acyl-group: 1) short-chain ACs; 2) medium-chain ACs; 3) long-chain ACs; 4) very long-chain ACs; 5) hydroxy ACs; 6) branched chain ACs; 7) unsaturated ACs; 8) dicarboxylic ACs and 9) miscellaneous ACs. Short-chain ACs have acyl-groups with two to five carbons (C2-C5), medium-chain ACs have acyl-groups with six to thirteen carbons (C6-C13), long-chain ACs have acyl-groups with fourteen to twenty once carbons (C14-C21) and very long-chain ACs have acyl groups with more than 22 carbons. (5Z,8Z)-10-[(2S,3R)-3-[(2Z)-oct-2-en-1-yl]oxiran-2-yl]deca-5,8-dienoylcarnitine is therefore classified as a long chain AC. As a long-chain acylcarnitine (5Z,8Z)-10-[(2S,3R)-3-[(2Z)-oct-2-en-1-yl]oxiran-2-yl]deca-5,8-dienoylcarnitine is generally formed through esterification with long-chain fatty acids obtained from the diet. The main function of most long-chain acylcarnitines is to ensure long chain fatty acid transport into the mitochondria (PMID: 22804748). Altered levels of long-chain acylcarnitines can serve as useful markers for inherited disorders of long-chain fatty acid metabolism. Carnitine palmitoyltransferase I (CPT I, EC:2.3.1.21) is involved in the synthesis of long-chain acylcarnitines (more than C12) on the mitochondrial outer membrane. Elevated serum/plasma levels of long-chain acylcarnitines are not only markers for incomplete FA oxidation but also are indicators of altered carbohydrate and lipid metabolism. High serum concentrations of long-chain acylcarnitines in the postprandial or fed state are markers of insulin resistance and arise from insulins inability to inhibit CPT-1-dependent fatty acid metabolism in muscles and the heart (PMID: 19073774). Increased intracellular content of long-chain acylcarnitines is thought to serve as a feedback inhibition mechanism of insulin action (PMID: 23258903). In healthy subjects, increased concentrations of insulin effectively inhibits long-chain acylcarnitine production. Several studies have also found increased levels of circulating long-chain acylcarnitines in chronic heart failure patients (PMID: 26796394). The study of acylcarnitines is an active area of research and it is likely that many novel acylcarnitines will be discovered in the coming years. It is also likely that many novel roles in health and disease will be uncovered. An excellent review of the current state of knowledge for acylcarnitines is available at [Dambrova et al. 2021, Physiological Reviews].
MG(0:0/20:3(5Z,8Z,14Z)-O(11S,12R)/0:0)
MG(0:0/20:3(5Z,8Z,14Z)-O(11S,12R)/0:0) is an oxidized monoacyglycerol (MG). Oxidized monoacyglycerols are glycerolipids in which the fatty acyl chain has undergone oxidation. As all oxidized lipids, oxidized monoacyglycerols belong to a group of biomolecules that have a role as signaling molecules. The biosynthesis of oxidized lipids is mediated by several enzymatic families, including cyclooxygenases (COX), lipoxygenases (LOX) and cytochrome P450s (CYP). Non-enzymatically oxidized lipids are produced by uncontrolled oxidation through free radicals and are considered harmful to human health (PMID: 33329396). As is the case with other lipids, monoacyglycerols can be substituted by different fatty acids, with varying lengths, saturation and degrees of oxidation attached at the C-1, C-2 and C-3 positions. Lipids are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Similarly to what occurs with lipids, the fatty acid distribution at the C-1 and C-2 positions of glycerol within oxidized lipids is continually in flux, owing to lipid degradation and the continuous lipid remodeling that occurs while these molecules are in membranes. Oxidized MGs can be synthesized via three different routes. In one route, the oxidized MG is synthetized de novo following the same mechanisms as for MGs but incorporating an oxidized acyl chain (PMID: 33329396). An alternative is the transacylation of the non-oxidized acyl chains with an oxidized acylCoA (PMID: 33329396). The third pathway results from the oxidation of the acyl chain while still attached to the MG backbone, mainly through the action of LOX (PMID: 33329396).