10-hydroxy-11-12-epoxyeicosa-5-8-14-trienoic-acid and 8-hydroxy-11-12-epoxyeicosa-5-9-14-trienoic-acid

This article reviews published evidence describing the enzymatic and nonenzymatic formation and the routes of metabolism of the hepoxilins. Also treated are the major approaches used for the chemical synthesis of these compounds and for some of their analogs.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Drug Stability; Leukotrienes; Molecular Structure

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Hemin; Humans; Leukotrienes; Lung; Molecular Conformation; Molecular Structure; Pineal Gland

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Calcium; Chemotaxis, Leukocyte; Humans; Insulin; Insulin Secretion; Neutrophils

1. This article reviews the formation, metabolism and pharmacological actions of the hepoxilins. These are biologically active hydroxy epoxide derivatives of arachidonic acid formed through the 12-lipoxygenase pathway. 2. This review summarizes literature data available at the time of writing of this article.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Humans

Zika virus (ZIKV) has emerged as one of the most medically relevant viral infections of the past decades; the devastating effects of this virus over the developing brain are a major matter of concern during pregnancy. Although the connection with congenital malformations are well documented, the mechanisms by which ZIKV reach the central nervous system (CNS) and the causes of impaired cortical growth in affected fetuses need to be better addressed. We performed a non-invasive, metabolomics-based screening of saliva from infants with congenital Zika syndrome (CZS), born from mothers that were infected with ZIKV during pregnancy. We were able to identify three biomarkers that suggest that this population suffered from an important inflammatory process; with the detection of mediators associated with glial activation, we propose that microcephaly is a product of immune response to the virus, as well as excitotoxicity mechanisms, which remain ongoing even after birth.

Topics: 8,11,14-Eicosatrienoic Acid; Biomarkers; Female; Fetal Development; Fetus; Humans; Infant; Infant, Newborn; Inflammation; Longitudinal Studies; Male; Metabolomics; Microcephaly; Mothers; Parturition; Pregnancy; Pregnancy Complications, Infectious; Saliva; Virus Diseases; Zika Virus; Zika Virus Infection

Pulmonary exacerbations in cystic fibrosis airways are accompanied by inflammation, neutrophilia, and mucous thickening. Cystic fibrosis sputum contains a large amount of uncleared DNA contributed by neutrophil extracellular trap (NET) formation from neutrophils. The exact mechanisms of the induction of NETosis in cystic fibrosis airways remain unclear, especially in uninfected lungs of patients with early cystic fibrosis lung disease. Here we show that Hepoxilin A3, a proinflammatory eicosanoid, and the synthetic analog of Hepoxilin B3, PBT-3, directly induce NETosis in human neutrophils. Furthermore, we show that Hepoxilin A3-mediated NETosis is NADPH-oxidase-dependent at lower doses of Hepoxilin A3, while it is NADPH-oxidase-independent at higher doses. Together, these results demonstrate that Hepoxilin A3 is a previously unrecognized inducer of NETosis in cystic fibrosis lungs and may represent a new therapeutic target for treating cystic fibrosis and other inflammatory lung diseases.

Topics: 8,11,14-Eicosatrienoic Acid; Cells, Cultured; Cystic Fibrosis; Extracellular Traps; Humans; Neutrophils

We have chemically synthesized several stable analogs of the naturally occurring hepoxilins, 12-LO products derived from arachidonic acid, which we found to have promising actions in a variety of test systems of disease. The analogs, PBTs, afford chemical and biological stability to the hepoxilin molecule. This article reviews some of our latest observations with the PBTs in the areas of inflammation (inhibition of the bleomycin-evoked lung fibrosis in mice in vivo), platelet aggregation (antagonism of the thromboxane receptor in human platelets in vitro) and thrombosis (inhibitors in vivo), and cancer (apoptosis of the human leukemia cell line, K562 in vitro and in vivo). The demonstration that the PBTs are active in vivo suggests that they can serve as a platform for their further development as novel therapeutics in disease.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Apoptosis; Bleomycin; Blood Platelets; Disease Models, Animal; Fibrinolytic Agents; Humans; K562 Cells; Leukemia, Experimental; Lung; Mice; Platelet Aggregation; Pulmonary Fibrosis

In this study we set out to investigate whether the inflammatory agents, bradykinin (BK) and platelet activating factor (PAF), affect the lipoxygenase pathway in rat skin in vivo and whether the main products so formed may be involved in the inflammatory actions of these agents. In vitro preparations of epidermis were also investigated to determine whether lipoxygenases are stimulated by these agents. We also investigated the actions of arachidonic acid and 12(S)-HPETE as substrates for the lipoxygenases. Our results indicated that 12-lipoxygenase is actively and selectively stimulated in a dose-dependent way in both preparations by the administration of BK and PAF; the main product, 12-HETE, was shown by chiral analysis to be exclusively of the S-configuration, indicating that 12(S)-lipoxygenase was present in the rat skin and was stimulated by these inflammatory agents. Hepoxilins were also formed but to a lesser extent in both in vivo and in vitro preparations. In separate experiments, 12(S)-HETE administered intradermally on its own (40 ng/site), increased vascular permeability as also seen with bradykinin (100 ng/site) and PAF (10 ng/site). However, unlike previously observed with hepoxilin A3 administration, 12(S)-HETE did not stimulate the action of BK on vascular permeability, suggesting that the two compounds may have different mechanisms of action to enhance inflammation. These observations suggest that the vascular permeability and plasma extravasation observed with both inflammatory agents (BK and PAF) may be mediated at least in part through the activation of 12(S)-lipoxygenase, resulting in enhanced formation of 12(S)-HETE which causes acute inflammation.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 8,11,14-Eicosatrienoic Acid; Animals; Arachidonate 12-Lipoxygenase; Bradykinin; Capillary Permeability; Enzyme Activation; Inflammation; Inflammation Mediators; Male; Platelet Activating Factor; Rats; Rats, Wistar; Skin

We recently found that normal human epidermis produces relatively high amounts of hepoxilins and trioxilins in vitro. Therefore, the aim of this study was to demonstrate the presence of these compounds in psoriatic lesions. Extracts from scales of patients with chronic stable plaque psoriasis were analyzed by a combination of high performance liquid chromatography and gas chromatography-mass spectrometry techniques. We found that the levels of hepoxilin B3 were more than 16-fold higher in psoriatic scales than in normal epidermis (3.2+/-2.3 and < 0.2 ng per mg, respectively), whereas hepoxilin A3 was not detected in any sample. Trioxilins were semiquantitated and referred to 12-hydroxyeicosatetraenoic acid, ratios of trioxilins A3 and B3 12-hydroxyeicosatetraenoic acid in psoriatic lesions were 0.65+/-0.23 and 0.32+/-0.28, respectively, and they were not detected in normal epidermis. The presence of a great amount of trioxilin A3 strongly suggests that hepoxilin A3 was present in psoriatic lesions and it was totally degraded to trioxilin A3 during the analysis procedure. Our results demonstrate that hepoxilins and trioxilins are produced by human skin in vivo and that the levels of these compounds are increased in psoriasis. The reported biologic activities of hepoxilins indicate that they could amplify and maintain the inflammatory response. Our results reinforce the idea that these compounds could play a role as mediators in the inflammatory response in skin, particularly in psoriasis.

Topics: 8,11,14-Eicosatrienoic Acid; Chromatography, High Pressure Liquid; Epidermis; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyeicosatetraenoic Acids; Psoriasis; Reference Values

We describe here the effects of two 12-lipoxygenase products, 12-HETE (12-hydroxyeicosa (5Z,8Z,10E,14Z) tetraenoic acid) and 12-HPETE (12-hydroperoxyeicosa (5Z,8Z,10E,14Z) tetraenoic acid), on the release of intracellular calcium in intact human neutrophils using the INDO-1 AM fluorescent dye technique. Both products dose dependently stimulate intracellular release, with 12-HETE being more powerful than 12-HPETE. The threshold concentration for 12-HETE was 5 ng/ml (1.5 x 10-8 M), while that for 12-HPETE was 10 ng/ml. The (12S) regioisomer was slightly more active than the (12R) isomer. The laser potency of 12-HPETE may be due to its conversion into the less active hepoxilins as incubation of neutrophils with (12S/R)-HPETE in a nonradioactive assay, using fluorescent ADAM esters of the products, generated mostly hepoxilin A3 (8-hydroxy-(11S,12S) epoxyeicosa (5Z,9E,14Z)trienoic acid), indicative of an enzymatic process. In contrast, boiled neutrophil preparations converted 12-HPETE primarily into hepoxilin B3 which previously showed to be derived nonenzymatically. This data demonstrates that 12-HETE, known to be generated in significant amounts by platelets, can act transcellularly to modify intracellular concentrations of calcium in neutrophils. This may in turn affect the responsiveness of these cells to other chemotactic factors.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 8,11,14-Eicosatrienoic Acid; Arachidonate 12-Lipoxygenase; Arachidonic Acid; Blood Platelets; Calcium; Chelating Agents; Fluorescent Dyes; Humans; Indoles; Leukotrienes; Neutrophils

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Blood Proteins; Bradykinin; Capillary Permeability; Drug Synergism; Injections, Intradermal; Male; Platelet Activating Factor; Rats; Rats, Wistar; Regional Blood Flow; Skin

Fluorescent anthryl (ADAM) derivatives of hepoxilins have been shown to possess good chromatographic properties affording good sensitivity for the high-performance liquid chromatographic analysis and detection of these compounds and related eicosanoids (12-hydroxyeicosatetraenoic acid) in biological samples. We report herein the separation of all possible stereoisomers of hepoxilins A3 and B3 as their methyl esters as well as their ADAM ester and acetate derivatives on a cellulose trisdimethyphenylcarbamate chiral stationary phase (Chiracel OD) in the normal-phase mode. This methodology is important to address the mechanistic route of biosynthesis of these products.

Topics: 8,11,14-Eicosatrienoic Acid; Acetates; Anthracenes; Chromatography, High Pressure Liquid; Esters; Fluorescent Dyes; Stereoisomerism

Available data obtained so far has indicated that hepoxilin formation from 12-HPETE is catalyzed by hemin and hemoglobin and is not affected through heating of these ferri-heme compounds suggestive of nonenzymatic processes. The present paper demonstrates for the first time that 12-HPETE is transformed into the hepoxilins A3 and B3 by intact cells (skin subcutis layer) and slices of several tissues (brain hippocampus and pineal gland) and that this transformation is inhibited by tissue boiling, indicating an enzymatic catalysis. The tissues employed are pharmacologically responsive to hepoxilins and hence the present data offer biochemical support of a potential biological role for the hepoxilins in these tissues.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Carbon Radioisotopes; Chromatography, High Pressure Liquid; Hippocampus; In Vitro Techniques; Leukotrienes; Male; Pineal Gland; Rats; Rats, Wistar; Skin

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; 8,11,14-Eicosatrienoic Acid; Animals; Brain; Cerebral Cortex; Evoked Potentials; Fatty Acids, Unsaturated; Hydroxyeicosatetraenoic Acids; In Vitro Techniques; Kinetics; Male; Membrane Potentials; Rats; Rats, Inbred Strains

Evidence is presented to show that pancreatic islets of Langerhans are capable of producing hepoxilins A3 and B3 from endogenous substrates as well as 14C-labeled 12-HPETE. Both hepoxilins are active in stimulating the release of insulin from these cells in the presence of 10 mM glucose. These experiments suggest that the hepoxilins may participate as potential endogenous mediators of insulin release in islets of Langerhans.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Fatty Acids, Unsaturated; Gas Chromatography-Mass Spectrometry; Hydroxyeicosatetraenoic Acids; In Vitro Techniques; Insulin; Islets of Langerhans; Rats; Rats, Inbred Strains

Isolated Krebs perifused rat pancreatic islets in the presence of 10 mM glucose convert 12S-HPETE into two hydroxy-epoxides, 8H-11,12-EPETE and 10H-11,12-EPETE for which we propose the name Hepoxilin A and B respectively. Hepoxilin A was investigated for its capacity to release insulin by this preparation. Insulin secretion by these cells, measured in the perifusate by radioimmunoassay, was dependent on the glucose concentration in the perifusing medium. Hepoxilin A dose dependently enhanced further the release of insulin during glucose (10 mM) stimulation (120 +/- 51% at 0.5 x 10(-6) M (n = 3) and 282 +/- 58% at 2.1 x 10(-6) M (n = 3) above control). These results suggest that Hepoxilin A (and possibly also Hepoxilin B) could be the active intermediate(s) involved in the potentiation of glucose dependent insulin secretion by both arachidonic acid and 12-HPETE.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acids; Carbon Radioisotopes; Dinoprostone; In Vitro Techniques; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Leukotrienes; Prostaglandins E; Rats; Rats, Inbred Strains

Arachidonic acid and 12-hydroperoxyeicosa-5,8, 10, 14-tetraenoic acid are converted by a 0-30% ammonium sulfate fraction (Fraction A) of the high speed supernatant of rat lung into two hydroxy epoxides (EH-1 and EH-2) which have been purified by high performance liquid chromatography. These hydroxy epoxides are converted quantitatively into two triols (10,11,12- from EH-1 and 8,11,12- from EH-2) by a 30-50% ammonium sulfate fraction (Fraction B) of the high speed supernatant. We propose the structures, 8-hydroxy-11,12-epoxyeicosa-5,9,14-trienoic acid (EH-2) and 10-hydroxy-11,12-epoxyeicosa-5,8,14-trienoic acids (EH-1) for these intermediates on the basis of mass spectral interpretation of several derivatives including the lithium aluminum hydride reduction product of both natural and 18Oxygenated derivatives.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acid; Arachidonic Acids; Carbon Radioisotopes; Chromatography, High Pressure Liquid; Epoxy Compounds; Ethers, Cyclic; Fatty Acids, Unsaturated; Isomerism; Lung; Male; Mass Spectrometry; Rats; Rats, Inbred Strains; Tritium