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Dar KB, Bhat AH, Amin S, Reshi BA, Zargar MA, Masood A, Ganie SA. Elucidating Critical Proteinopathic Mechanisms and Potential Drug Targets in Neurodegeneration. Cell Mol Neurobiol 2019; 40:313-345. [PMID: 31584139 DOI: 10.1007/s10571-019-00741-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/06/2019] [Indexed: 12/18/2022]
Abstract
Neurodegeneration entails progressive loss of neuronal structure as well as function leading to cognitive failure, apathy, anxiety, irregular body movements, mood swing and ageing. Proteomic dysregulation is considered the key factor for neurodegeneration. Mechanisms involving deregulated processing of proteins such as amyloid beta (Aβ) oligomerization; tau hyperphosphorylation, prion misfolding; α-synuclein accumulation/lewy body formation, chaperone deregulation, acetylcholine depletion, adenosine 2A (A2A) receptor hyperactivation, secretase deregulation, leucine-rich repeat kinase 2 (LRRK2) mutation and mitochondrial proteinopathies have deeper implications in neurodegenerative disorders. Better understanding of such pathological mechanisms is pivotal for exploring crucial drug targets. Herein, we provide a comprehensive outlook about the diverse proteomic irregularities in Alzheimer's, Parkinson's and Creutzfeldt Jakob disease (CJD). We explicate the role of key neuroproteomic drug targets notably Aβ, tau, alpha synuclein, prions, secretases, acetylcholinesterase (AchE), LRRK2, molecular chaperones, A2A receptors, muscarinic acetylcholine receptors (mAchR), N-methyl-D-aspartate receptor (NMDAR), glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) and mitochondrial/oxidative stress-related proteins for combating neurodegeneration and associated cognitive and motor impairment. Cross talk between amyloidopathy, synucleinopathy, tauopathy and several other proteinopathies pinpoints the need to develop safe therapeutics with ability to strike multiple targets in the aetiology of the neurodegenerative disorders. Therapeutics like microtubule stabilisers, chaperones, kinase inhibitors, anti-aggregation agents and antibodies could serve promising regimens for treating neurodegeneration. However, drugs should be target specific, safe and able to penetrate blood-brain barrier.
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Affiliation(s)
- Khalid Bashir Dar
- Department of Clinical Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India.,Department of Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Aashiq Hussain Bhat
- Department of Clinical Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India.,Department of Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Shajrul Amin
- Department of Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Bilal Ahmad Reshi
- Department of Biotechnology, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Mohammad Afzal Zargar
- Department of Clinical Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Akbar Masood
- Department of Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India
| | - Showkat Ahmad Ganie
- Department of Clinical Biochemistry, Faculty of Biological Sciences, University of Kashmir, Srinagar, India.
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The Lipoxygenases: Their Regulation and Implication in Alzheimer's Disease. Neurochem Res 2015; 41:243-57. [PMID: 26677076 PMCID: PMC4773476 DOI: 10.1007/s11064-015-1776-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/06/2015] [Accepted: 11/14/2015] [Indexed: 02/03/2023]
Abstract
Inflammatory processes and alterations of lipid metabolism play a crucial role in Alzheimer’s disease (AD) and other neurodegenerative disorders. Polyunsaturated fatty acids (PUFA) metabolism impaired by cyclooxygenases (COX-1, COX-2), which are responsible for formation of several eicosanoids, and by lipoxygenases (LOXs) that catalyze the addition of oxygen to linolenic, arachidonic (AA), and docosahexaenoic acids (DHA) and other PUFA leading to formation of bioactive lipids, significantly affects the course of neurodegenerative diseases. Among several isoforms, 5-LOX and 12/15-LOX are especially important in neuroinflammation/neurodegeneration. These two LOXs are regulated by substrate concentration and availability, and by phosphorylation/dephosphorylation through protein kinases PKA, PKC and MAP-kinases, including ERK1/ERK2 and p38. The protein/protein interaction also is involved in the mechanism of 5-LOX regulation through FLAP protein and coactosin-like protein. Moreover, non-heme iron and calcium ions are potent regulators of LOXs. The enzyme activity significantly depends on the cell redox state and is differently regulated by various signaling pathways. 5-LOX and 12/15-LOX convert linolenic acid, AA, and DHA into several bioactive compounds e.g. hydroperoxyeicosatetraenoic acids (5-HPETE, 12S-HPETE, 15S-HPETE), which are reduced to corresponding HETE compounds. These enzymes synthesize several bioactive lipids, e.g. leucotrienes, lipoxins, hepoxilins and docosahexaenoids. 15-LOX is responsible for DHA metabolism into neuroprotectin D1 (NPD1) with significant antiapoptotic properties which is down-regulated in AD. In this review, the regulation and impact of 5-LOX and 12/15-LOX in the pathomechanism of AD is discussed. Moreover, we describe the role of several products of LOXs, which may have significant pro- or anti-inflammatory activity in AD, and the cytoprotective effects of LOX inhibitors.
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Selective reduction of hydroperoxyeicosatetraenoic acids to their hydroxy derivatives by apolipoprotein D: implications for lipid antioxidant activity and Alzheimer's disease. Biochem J 2012; 442:713-21. [PMID: 22150111 DOI: 10.1042/bj20111166] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ApoD (apolipoprotein D) is up-regulated in AD (Alzheimer's disease) and upon oxidative stress. ApoD inhibits brain lipid peroxidation in vivo, but the mechanism is unknown. Specific methionine residues may inhibit lipid peroxidation by reducing radical-propagating L-OOHs (lipid hydroperoxides) to non-reactive hydroxides via a reaction that generates MetSO (methionine sulfoxide). Since apoD has three conserved methionine residues (Met(49), Met(93) and Met(157)), we generated recombinant proteins with either one or all methionine residues replaced by alanine and assessed their capacity to reduce HpETEs (hydroperoxyeicosatetraenoic acids) to their HETE (hydroxyeicosatetraenoic acid) derivatives. ApoD, apoD(M49-A) and apoD(M157-A) all catalysed the reduction of HpETEs to their corresponding HETEs. Amino acid analysis of HpETE-treated apoD revealed a loss of one third of the methionine residues accompanied by the formation of MetSO. Additional studies using apoD(M93-A) indicated that Met(93) was required for HpETE reduction. We also assessed the impact that apoD MetSO formation has on protein aggregation by Western blotting of HpETE-treated apoD and human brain samples. ApoD methionine oxidation was associated with formation of apoD aggregates that were also detected in the hippocampus of AD patients. In conclusion, conversion of HpETE into HETE is mediated by apoD Met(93), a process that may contribute to apoD antioxidant function.
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Molecular mechanisms of short-term habituation in the leech Hirudo medicinalis. Behav Brain Res 2012; 229:235-43. [DOI: 10.1016/j.bbr.2012.01.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/11/2012] [Accepted: 01/12/2012] [Indexed: 02/06/2023]
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Harrington MG, Fonteh AN, Arakaki X, Cowan RP, Ecke LE, Foster H, Hühmer AF, Biringer RG. Capillary endothelial Na(+), K(+), ATPase transporter homeostasis and a new theory for migraine pathophysiology. Headache 2010; 50:459-78. [PMID: 19845787 PMCID: PMC8020446 DOI: 10.1111/j.1526-4610.2009.01551.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cerebrospinal fluid sodium concentration ([Na(+)](csf)) increases during migraine, but the cause of the increase is not known. OBJECTIVE Analyze biochemical pathways that influence [Na(+)](csf) to identify mechanisms that are consistent with migraine. METHOD We reviewed sodium physiology and biochemistry publications for links to migraine and pain. RESULTS Increased capillary endothelial cell (CEC) Na(+), K(+), -ATPase transporter (NKAT) activity is probably the primary cause of increased [Na(+)](csf). Physiological fluctuations of all NKAT regulators in blood, many known to be involved in migraine, are monitored by receptors on the luminal wall of brain CECs; signals are then transduced to their abluminal NKATs that alter brain extracellular sodium ([Na(+)](e)) and potassium ([K(+)](e)). CONCLUSIONS We propose a theoretical mechanism for aura and migraine when NKAT activity shifts outside normal limits: (1) CEC NKAT activity below a lower limit increases [K(+)](e), facilitates cortical spreading depression, and causes aura; (2) CEC NKAT activity above an upper limit elevates [Na(+)](e), increases neuronal excitability, and causes migraine; (3) migraine-without-aura may arise from CEC NKAT over-activity without requiring a prior decrease in activity and its consequent spreading depression; (4) migraine triggers disturb, and treatments improve, CEC NKAT homeostasis; (5) CEC NKAT-induced regulation of neural and vasomotor excitability coordinates vascular and neuronal activities, and includes occasional pathology from CEC NKAT-induced apoptosis or cerebral infarction.
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Affiliation(s)
- Michael G Harrington
- Huntington Medical Research Institutes - Molecular Neurology, Pasadena, CA 91101, USA
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Uz T, Dimitrijevic N, Imbesi M, Manev H, Manev R. Effects of MK-886, a 5-lipoxygenase activating protein (FLAP) inhibitor, and 5-lipoxygenase deficiency on the forced swimming behavior of mice. Neurosci Lett 2008; 436:269-72. [PMID: 18403121 DOI: 10.1016/j.neulet.2008.03.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 03/04/2008] [Accepted: 03/18/2008] [Indexed: 12/29/2022]
Abstract
A common biological pathway may contribute to the comorbidity of atherosclerosis and depression. Increased activity of the enzymatic 5-lipoxygenase (5-LOX, 5LO) pathway is a contributing factor in atherosclerosis and a 5-LOX inhibitor, MK-886, is beneficial in animal models of atherosclerosis. In the brain, MK-886 increases phosphorylation of the glutamate receptor subunit GluR1, and the increased phosphorylation of this receptor has been associated with antidepressant treatment. In this work, we evaluated the behavioral effects of MK-886 in an automated assay of mouse forced swimming, which identifies antidepressant activity as increased climbing behavior and/or decreased rest time. Whereas a single injection of MK-886 (3 and 10 mg/kg) did not affect forced swimming behaviors assayed 30 min later, six daily injections of 3 mg/kg MK-886 slightly increased climbing and significantly reduced rest time in wild-type mice but not in 5-LOX-deficient mice. A diet delivery of MK-886, 4 micro/(100 mg(body-weight)day), required 3 weeks to affect forced swimming; it increased climbing behavior. Climbing behavior was also increased in naive 5-LOX-deficient mice compared to naive wild-type controls. These results suggest that 5-LOX inhibition and deficiency may be associated with antidepressant activity. Increased climbing in a forced swimming assay is a typical outcome of antidepressants that increase noradrenergic and dopaminergic activity. Interestingly, 5-LOX deficiency and MK-886 treatment have been shown to be capable of increasing the behavioral effects of a noradrenaline/dopamine-potentiating drug, cocaine. Future research is needed to evaluate the clinical relevance of our findings.
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Affiliation(s)
- Tolga Uz
- The Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA
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Strauss KI. Antiinflammatory and neuroprotective actions of COX2 inhibitors in the injured brain. Brain Behav Immun 2008; 22:285-98. [PMID: 17996418 PMCID: PMC2855502 DOI: 10.1016/j.bbi.2007.09.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/14/2007] [Accepted: 09/20/2007] [Indexed: 12/22/2022] Open
Abstract
Overexpression of COX2 appears to be both a marker and an effector of neural damage after a variety of acquired brain injuries, and in natural or pathological aging of the brain. COX2 inhibitors may be neuroprotective in the brain by reducing prostanoid and free radical synthesis, or by directing arachidonic acid down alternate metabolic pathways. The arachidonic acid shunting hypothesis proposes that COX2 inhibitors' neuroprotective effects may be mediated by increased formation of potentially beneficial eicosanoids. Under conditions where COX2 activity is inhibited, arachidonic acid accumulates or is converted to eicosanoids via lipoxygenases and cytochrome P450 (CYP) epoxygenases. Several P450 eicosanoids have been demonstrated to have beneficial effects in the brain and/or periphery. We suspect that arachidonic acid shunting may be as important to functional recovery after brain injuries as altered prostanoid formation per se. Thus, COX2 inhibition and arachidonic acid shunting have therapeutic implications beyond the suppression of prostaglandin synthesis and free radical formation.
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Affiliation(s)
- Kenneth I. Strauss
- Mayfield Neurotrauma Research Lab, Department of Neurosurgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, ML515, Cincinnati, OH 45267 ()
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Slyshenkov VS, Shevalye AA, Moiseenok AG. Pantothenate prevents disturbances in the synaptosomal glutathione system and functional state of synaptosomal membrane under oxidative stress conditions. NEUROCHEM J+ 2007. [DOI: 10.1134/s1819712407030105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zhao YN, Pan Y, Tao JL, Xing DM, Du LJ. Study on cardioactive effects of brazilein. Pharmacology 2005; 76:76-83. [PMID: 16319518 DOI: 10.1159/000089721] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Accepted: 09/26/2005] [Indexed: 11/19/2022]
Abstract
Brazilein (6a,7-dihydro-3,6a,10-trihydroxy-benz[b]indeno[1,2-d]pyran-9(6H)-one) is a compound obtained in a large amount from Caesalpinia sappan ethanol extracts with a high purity of about 98%. In isolated cardiac tissues, we found that brazilein exhibited a positive inotropic action in a concentration-dependent manner with little effect on heart rate and coronary perfusion. To study its possible mode of action, isolated rat hearts were treated with propranolol. This treatment did not alter the cardiotonic effect of brazilein, suggesting that this effect does not involve stimulation of beta-adrenoceptors. On the other hand, an analysis of the interaction between Na(+),K(+)-ATPase and brazilein was carried out. Albino guinea pig erythrocytes (mainly alpha1-Na(+),K(+)-ATPase isoforms) enriched with Na(+),K(+)-ATPase isoforms were utilized to compare the inhibition promoted by brazilein with that of classical inhibitors such as the cardiac glycoside deslanoside. Analysis of inhibition curves revealed that unlike deslanoside, brazilein had a relatively low affinity for erythrocyte isoforms and failed to completely inhibit the Na(+),K(+)-ATPase activity. The extent of the maximum inhibition rate was about 50%. The inhibitory effect of brazilein was not antagonized by 10 mmol/l K(+), as observed with deslanoside. Electrocardiogram research in vivo showed that brazilein did not induce the ventricular arrhythmias observed with deslanoside, suggesting that brazilein might have a less adverse effect and higher therapeutic index than cardiac glycosides. In light of all the above-mentioned observations, it can be concluded that brazilein, a molecule with a non-steroidal skeleton, produced its positive inotropic effect through inhibiting Na(+),K(+)-ATPase and could thus serve as a structural paradigm to develop new inotropic drugs.
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Affiliation(s)
- Yu Nan Zhao
- Laboratory of Pharmaceutical Sciences, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100-084, China
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Gopez JJ, Yue H, Vasudevan R, Malik AS, Fogelsanger LN, Lewis S, Panikashvili D, Shohami E, Jansen SA, Narayan RK, Strauss KI. Cyclooxygenase-2-specific inhibitor improves functional outcomes, provides neuroprotection, and reduces inflammation in a rat model of traumatic brain injury. Neurosurgery 2005; 56:590-604. [PMID: 15730585 PMCID: PMC1513642 DOI: 10.1227/01.neu.0000154060.14900.8f] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Accepted: 12/13/2004] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Increases in brain cyclooxygenase-2 (COX2) are associated with the central inflammatory response and with delayed neuronal death, events that cause secondary insults after traumatic brain injury. A growing literature supports the benefit of COX2-specific inhibitors in treating brain injuries. METHODS DFU [5,5-dimethyl-3(3-fluorophenyl)-4(4-methylsulfonyl)phenyl-2(5)H)-furanone] is a third-generation, highly specific COX2 enzyme inhibitor. DFU treatments (1 or 10 mg/kg intraperitoneally, twice daily for 3 d) were initiated either before or after traumatic brain injury in a lateral cortical contusion rat model. RESULTS DFU treatments initiated 10 minutes before injury or up to 6 hours after injury enhanced functional recovery at 3 days compared with vehicle-treated controls. Significant improvements in neurological reflexes and memory were observed. DFU initiated 10 minutes before injury improved histopathology and altered eicosanoid profiles in the brain. DFU 1 mg/kg reduced the rise in prostaglandin E2 in the brain at 24 hours after injury. DFU 10 mg/kg attenuated injury-induced COX2 immunoreactivity in the cortex (24 and 72 h) and hippocampus (6 and 72 h). This treatment also decreased the total number of activated caspase-3-immunoreactive cells in the injured cortex and hippocampus, significantly reducing the number of activated caspase-3-immunoreactive neurons at 72 hours after injury. DFU 1 mg/kg amplified potentially anti-inflammatory epoxyeicosatrienoic acid levels by more than fourfold in the injured brain. DFU 10 mg/kg protected the levels of 2-arachidonoyl glycerol, a neuroprotective endocannabinoid, in the injured brain. CONCLUSION These improvements, particularly when treatment began up to 6 hours after injury, suggest exciting neuroprotective potential for COX2 inhibitors in the treatment of traumatic brain injury and support the consideration of Phase I/II clinical trials.
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Affiliation(s)
- Jonas J. Gopez
- Department of Neurosurgery, Temple University, School of Medicine, Philadelphia, Pennsylvania
| | - Hongfei Yue
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania
| | - Ram Vasudevan
- Department of Neurosurgery, Temple University, School of Medicine, Philadelphia, Pennsylvania
| | - Amir S. Malik
- Department of Neurosurgery, University of Texas, Houston Medical Center, Houston, Texas
| | - Lester N. Fogelsanger
- Department of Neurosurgery, Temple University, School of Medicine, Philadelphia, Pennsylvania
| | - Shawn Lewis
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | | | - Esther Shohami
- Department of Pharmacology, Hebrew University, Jerusalem, Israel
| | - Susan A. Jansen
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania
| | - Raj K. Narayan
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Kenneth I. Strauss
- Reprint requests: Kenneth I. Strauss, Ph.D., Department of Neurosurgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, ML515, Cincinnati, OH 45267-0515.
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Scuri R, Mozzachiodi R, Brunelli M. Role for calcium signaling and arachidonic acid metabolites in the activity-dependent increase of AHP amplitude in leech T sensory neurons. J Neurophysiol 2005; 94:1066-73. [PMID: 15872070 DOI: 10.1152/jn.00075.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have revealed a new form of activity-dependent modulation of the afterhyperpolarization (AHP) in tactile (T) neurons of the leech Hirudo medicinalis. The firing of T cells is characterized by an AHP, which is mainly due to the activity of the Na+/K+ ATPase. Low-frequency repetitive stimulation of T neurons leads to a robust increment of the AHP amplitude, which is correlated with a synaptic depression between T neuron and follower cells. In the present study, we explored the molecular cascades underlying the AHP increase. We tested the hypothesis that this activity-dependent phenomenon was triggered by calcium influx during neural activity by applying blockers of voltage-dependent Ca2+ channels. We report that AHP increase requires calcium influx that, in turn, induces release of calcium from intracellular stores so sustaining the enhancement of AHP. An elevation of the intracellular calcium can activate the cytosolic isoforms of the phosholipase A2 (PLA2). Therefore we analyzed the role of PLA2 in the increase of the AHP, and we provide evidence that not only PLA2 but also the recruitment of arachidonic acid metabolites generated by the 5-lipoxygenase pathway are necessary for the induction of AHP increase. These data indicate that a sophisticated cascade of intracellular signals links the repetitive discharge of T neurons to the activation of molecular pathways, which finally may alter the activity of critical enzymes such as the Na+/K+ ATPase, that sustains the generation of the AHP and its increase during repetitive stimulation. These results also suggest the potential importance of the poorly studied 5-lipoxygenase pathway in forms of neuronal plasticity.
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Affiliation(s)
- Rossana Scuri
- Department of Physiology and Biochemistry G. Moruzzi, University of Pisa, Pisa, Italy.
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Lebeau A, Terro F, Rostene W, Pelaprat D. Blockade of 12-lipoxygenase expression protects cortical neurons from apoptosis induced by β-amyloid peptide. Cell Death Differ 2004; 11:875-84. [PMID: 15105833 DOI: 10.1038/sj.cdd.4401395] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The cyclo-oxygenase (COX) and lipoxygenase (LOX) pathways belong to the eicosanoid synthesis pathway, a major component of the chronic inflammatory process occurring in Alzheimer's disease (AD). Clinical studies reported beneficial effects of COX inhibitors, but little is known about the involvement of LOXs in AD pathogenesis. beta-amyloid peptide (A beta) accumulation contributes to neurodegeneration in AD, but mechanisms underlying A beta toxicity have not been fully elucidated yet. Here, using an antisense oligonucleotide-based strategy, we show that blockade of 12-LOX expression prevents both A beta-induced apoptosis and overexpression of c-Jun, a factor required for the apoptotic process, in cortical neurons. Conversely, the 12-LOX metabolite, 12(S)-HETE (12(S)-hydroxy-(5Z, 8Z, 10E, 14Z)-eicosatetraenoic acid), promoted c-Jun-dependent apoptosis. Specificity of the 12-LOX involvement was further supported by the observed lack of contribution of 5-LOX in this process. These data indicate that blockade of 12-LOX expression disrupts a c-Jun-dependent apoptosis pathway, and suggest that 12-LOX may represent a new target for the treatment of AD.
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Affiliation(s)
- A Lebeau
- Unité 339 INSERM-UPMC, Hôpital Saint-Antoine, 75571 Paris Cedex 12, France
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Durmaz R, Ertilav K, Akyüz F, Kanbak G, Bildirici K, Tel E. Lazaroid U-74389G attenuates edema in rat brain subjected to post-ischemic reperfusion injury. J Neurol Sci 2004; 215:87-93. [PMID: 14568134 DOI: 10.1016/s0022-510x(03)00207-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aim of the present study was to determine the potential therapeutic value of 21-aminosteroid U-74389G, on blood-brain barrier (BBB) breakdown and edema in association with the changes in synaptosomal Na(+)/K(+) and Mg(2+)/Ca(2+)-ATPase activities in rat brain subjected to post-ischemic reperfusion injury. Brain ischemia was achieved by means of four-vessel occlusion model for 25 min and animals were sacrificed after 12 h reperfusion. An increase of cerebral tissue water content, blood-brain disruption and the changes of synaptosomal Na(+)/K(+) and Mg(2+)/Ca(2+)-ATPases activities were evaluated. U-74389G was given intraperitoneally at two times as 5 mg/kg at 10 min prior to ischemia and at the beginning of reperfusion. Edema was determined by means of wet-dried weight method, and BBB of extravasation of Evan's blue dye. Extravasation of Evan's blue dye into brain following ischemia and reperfusion was 2.4-fold of control value and brought close to control levels by the effect of U-74389G (p<0.001). Post-ischemic reperfusion injury caused an increase of 3.7% in tissue water content of whole brain and administration of U-74389G lowered the cerebral edema (p<0.001). The loses in the Na(+)/K(+)-ATPase and Mg(2+)/Ca(2+)-ATPase activities occurred as 42.1% (p<0.01) and 65.7% (p<0.001) of control value, respectively. While Mg(2+)/Ca(2+)-ATPase activity was enhanced compared to vehicle-treated group of animals (p<0.01), Na(+)/K(+)-ATPase activity was fully recovered when compared to control by U-74389G (p>0.05). U-74389G also significantly attenuated neuronal necrosis (p<0.001) which was determined in the hippocampal CA1 subfield. Blood-brain barrier protection, attenuation of brain edema and neuronal necrosis concomitant with the stabilizing of membrane-bound enzymes brought about by the effect of U-74389G suggest that 21-aminosteroids are worthy of consideration in the acute treatment of cerebral ischemia.
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Affiliation(s)
- Ramazan Durmaz
- Department of Neurosurgery, Medical Faculty of Osmangazi University, 26480 Eskişehir, Turkey.
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Zhang NY, Kitagawa K, Wu B, Inagaki C. Soybean-derived phosphatidylinositol recovers amyloid beta protein-induced neurotoxicity in cultured rat hippocampal neurons. Neurosci Lett 2003; 350:105-8. [PMID: 12972164 DOI: 10.1016/s0304-3940(03)00896-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Effects of soybean-derived phosphatidylinositol (PI) on amyloid beta protein (10 nM Abeta(25-35))-induced changes in Cl(-)-ATPase activity, intracellular Cl- concentration ([Cl-]i) and glutamate neurotoxicity were examined using cultured rat hippocampal neurons. Soybean-derived PI (> or =5 nM) dose-dependently recovered Abeta-induced decrease in neuronal Cl(-)-ATPase activity without any changes in the activities of Na+,K(+)-ATPase and anion-insensitive Mg(2+)-ATPase. Soybean-derived PI reduced Abeta-induced elevation of [Cl-](i) as assayed using a Cl(-)-sensitive fluorescent dye, and prevented Abeta-induced aggravation of glutamate neurotoxicity assayed by mitochondrial 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt reducing activity and plasma membrane lactate dehydrogenase release. These data suggest that soybean-derived PI may be useful as a therapeutic and/or preventive strategy for Alzheimer's disease.
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Affiliation(s)
- Nan-Yan Zhang
- Department of Pharmacology, Kansai Medical University, Fumizono-cho 10-15, Moriguchi, Osaka 570-8506, Japan
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Aragno M, Cutrin JC, Mastrocola R, Perrelli MG, Restivo F, Poli G, Danni O, Boccuzzi G. Oxidative stress and kidney dysfunction due to ischemia/reperfusion in rat: attenuation by dehydroepiandrosterone. Kidney Int 2003; 64:836-43. [PMID: 12911533 DOI: 10.1046/j.1523-1755.2003.00152.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The pathogenesis of ischemia/reperfusion (I/R) involves generation of reactive oxygen and nitrogen species. This in vivo study investigates the effect of dehydroepiandrosterone (DHEA), a physiologic steroid with antioxidant properties, on oxidative balance and renal dysfunctions induced by monolateral I/R. METHODS Normal and DHEA-treated rats (4 mg/day x 21 days, orally) were subjected to monolateral renal I/R (30 minutes/6 hours). The oxidative state was determined by measuring hydrogen peroxide level and activities of glutathione-peroxidase, catalase, and superoxide dismutase. Tumor necrosis factor-alpha (TNF-alpha) and nitric oxide production and inducible nitric oxide synthase (iNOS) levels were also measured. Hydroxynonenal content was used to probe lipid peroxidation. Functional parameters determined were creatinine levels and Na/K-ATPase activity. Immunohistochemical and morphologic studies were also performed. RESULTS A markedly pro-oxidant state was evident in the kidney of rats subjected to I/R. Both hydrogen peroxide and reactive nitrogen species (nitric oxide and iNOS) increased, whereas antioxidants decreased. Oxidant species induce TNF-alpha increase, which, in turn, produces lipoperoxidative processes, as documented by the increased hydroxynonenal (HNE) level. As final result, impaired renal functionality, hydropic degeneration, and vacuolization of proximal convolute tubules were observed in kidneys of I/R rats. DHEA pretreatment improved the parameters considered. CONCLUSION I/R induces oxidative stress and consequently damages the proximal convolute renal tubules. Rats supplemented with DHEA and subjected to I/R had reduced pro-oxidant state, oxidative damage, and improved renal functionality, indicating an attenuation of oxidative injury and dysfunctions mediated by I/R.
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Affiliation(s)
- Manuela Aragno
- Department of Experimental Medicine and Oncology, General Pathology Section, University of Turin, Turin, Italy
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16
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Suketa Y. [Fundamental and applied studies on transport and metabolism of electrolytes and glucose--aim to contact with molecular biology]. YAKUGAKU ZASSHI 2002; 122:507-25. [PMID: 12187767 DOI: 10.1248/yakushi.122.507] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The authors' research focuses on polyuria, natriuresis, glucosuria, glycemia, and renal calcification in occupational lead poisoning and endemic fluorosis. Changes in electrolyte mobilization and in glucose metabolism and transport following the administration of lead compounds or fluoride were examined to elucidate these mechanisms. The results suggest fundamental approaches to the mechanism of aging and life style diseases. Our results show that: 1) Natriuresis and polyuria in lead poisoning and fluorosis are due to a decrease in renal Na/K-ATPase activity; 2) Renal calcification in fluorosis is due to stimulation of parathyroid function and activation of the renal phosphatidylinositol cascade; 3) Glycemia in fluorosis is due to elevation of renal and hepatic glucose-6-phosphatase activities; 4) Glusosuria in fluorosis is due to decreased renal Na/K-ATPase activity (but fluoride administered directly did not damage the renal Na/glucose cotransporter (SGLT); 5) Renal calcification in fluorosis is due to stimulation of parathyroid function; and 6) The decrease in renal Na/K-ATPase and SGLT activities with aging and hypertension is due to a decrease in phosphorylation activity by protein kinase C (PKC) etc. (decrease in PKC productivity with aging and hypertension).
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Affiliation(s)
- Yasunobu Suketa
- University of Shizuoka School of Pharmaceutical Sciences, 52-1 Yada, Shizuoka 422-8526, Japan.
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17
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Aragno M, Parola S, Brignardello E, Manti R, Betteto S, Tamagno E, Danni O, Boccuzzi G. Oxidative stress and eicosanoids in the kidneys of hyperglycemic rats treated with dehydroepiandrosterone. Free Radic Biol Med 2001; 31:935-42. [PMID: 11595378 DOI: 10.1016/s0891-5849(01)00669-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidative stress plays a crucial role in the pathogenesis of chronic diabetic complications. Normoglycemic and streptozotocin-diabetic rats were treated with dehydroepiandrosterone (DHEA) (4 mg/d per rat) for 3 weeks. At the end of treatment, hydroxynonenal, hydroperoxyeicosatetraenoic acids and antioxidant levels, as well as Na/K-ATPase activity and membrane fatty acids composition were evaluated in kidney homogenates. Chronic hyperglycemia caused a marked increase of both hydroxynonenal and lipoxygenase pathway products and a drop in both GSH levels and membrane Na/K-ATPase activity. DHEA treatment restored the antioxidant levels to close to the control value and considerably reduced hydroxynonenal and hydroperoxyeicosatetraenoic acid levels. Moreover, DHEA counteracted the detrimental effect of hyperglycemia on membrane function: the drop of Na/K-ATPase activity in diabetic animals was significantly inhibited by DHEA treatment. These results show that DHEA reduces oxidative stress and the consequent increase of lipoxygenase pathway products induced by experimental diabetes in rat kidney; they also suggest that, by reducing the inflammatory response to oxidative stress, DHEA treatment might delay the progression of diabetic kidney disease.
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Affiliation(s)
- M Aragno
- Department of Experimental Medicine and Oncology, General Pathology Section, University of Turin, Turin, Italy
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18
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Foley TD. The cyclooxygenase hydroperoxide product PGG(2) activates synaptic nitric oxide synthase: a possible antioxidant response to membrane lipid peroxidation. Biochem Biophys Res Commun 2001; 286:235-8. [PMID: 11500026 DOI: 10.1006/bbrc.2001.5378] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide is a potent inhibitor of membrane lipid peroxidation. It is unknown, however, whether nitric oxide synthase (NOS) activity increases under conditions of membrane lipid peroxidation. Importantly, cyclooxygenase (COX)-catalyzed peroxidation of arachidonic acid is well-established to be increased by lipid hydroperoxides. The results of the present study demonstrate that the COX hydroperoxide product prostaglandin G(2) (PGG(2)) greatly stimulated NOS activity in synaptosomal membrane fractions from rat brain in a dose-dependent (EC(50) = 0.2 microM) manner in the presence of ATP and the antioxidant urate. NOS activation was also produced, albeit to a lesser extent, by 15-hydroperoxyeicosatetraenoic acid (15-HPETE) but not by the corresponding hydroxy compounds PGH(2) and 15-HETE or by hydrogen peroxide. These findings demonstrate that PGG(2)-activated synaptic NOS by a hydroperoxide-mediated pathway and support the view that NOS activation may be an important physiological response to lipid peroxidation.
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Affiliation(s)
- T D Foley
- Biochemistry Program, University of Scranton, Scranton, Pennsylvania 18510, USA.
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19
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Le Foll I, Duval DP. Programmed cell death induced by glutathione depletion in PC 12 cells is blocked by inhibitors of 12 lipoxygenase, but does not appear to be mediated through the formation of 12 HETE derivatives. Free Radic Biol Med 2001; 30:793-802. [PMID: 11275479 DOI: 10.1016/s0891-5849(01)00467-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Lipoxygenase metabolites have been postulated to be involved in the degenerative events provoked by oxidative stress in neuronal and nonneuronal targets, but their roles remain controversial. In the present work, we investigated the putative role of 12 lipoxygenase metabolites in the programmed cell death induced by glutathione depletion in PC 12 cells. Determinations of 12 lipoxygenase expression and activity reveal the presence of the enzyme in PC 12 cells, but the formation of arachidonate metabolites appears rather low and is not influenced by glutathione depletion. In addition, although the death induced by buthionine sulfoximine (BSO) treatment is abolished by known inhibitors of lipoxygenase enzymes, dexamethasone, a potent steroidal inhibitor of both cyclooxygenase and lipoxygenase pathways, fails to protect the cells from BSO-induced degeneration. Finally, incubation of the cells for 24 h in the presence of exogenous 12 HETE did not induce any significant decrease in cell viability. Our results indicate that 12 lipoxygenase is unlikely to play a major role in the process of cell degeneration provoked by glutathione depletion.
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Affiliation(s)
- I Le Foll
- Université de Caen, CNRS-UMR 6551, Caen, France
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20
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Wiswedel I, Bohne M, Hirsch D, Kühn H, Augustin W, Gollnick H. A sensitive gas chromatography-mass spectrometry assay reveals increased levels of monohydroxyeicosatetraenoic acid isomers in human plasma after extracorporeal photoimmunotherapy and under in vitro ultraviolet A exposure. J Invest Dermatol 2000; 115:499-503. [PMID: 10951289 DOI: 10.1046/j.1523-1747.2000.00053.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Extracorporeal photoimmunotherapy (photopheresis) is a highly effective therapy in the treatment of various disorders. Although extracorporeal photoimmunotherapy has been successfully used for more than 10 y, its mechanism of action is still unclear. The formation of reactive oxygen species have been implicated in extracorporeal photoimmunotherapy, but malonyl dialdehyde as a marker of systemic lipid peroxidation did not increase significantly during treatment. To investigate further the involvement of reactive oxygen species in extracorporeal photoimmunotherapy, we have introduced a highly sensitive negative ion gas chromatography-mass spectrometry based method for quantitating oxygenated arachidonic acid isomers (hydroxyeicosatetraenoic acids) in plasma samples of patients treated with extracorporeal photoimmunotherapy. In the plasma of healthy volunteers pmole amounts of 2-, 3-, 5-, 8-12-, and 15-hydroxyeicosatetraenoic acid were detected and we observed a dose-dependent augmentation in these metabolites when the blood was irradiated with increasing doses of ultraviolet A in the presence of the photosensitizer 8-methoxypsoralen. Analysis of plasma samples obtained from patients before and after extracorporeal photoimmunotherapy revealed a characteristic increase in total hydroxyeicosatetraenoic acid levels, particularly of 5-hydroxyeicosatetraenoic acid which contributed 80% to the sum of all hydroxyeicosatetraenoic acid isomers. Chiral phase high-performance liquid chromatography indicated almost equal amounts of 5S- and 5R-hydroxyeicosatetraenoic acid suggesting that the majority of lipid peroxidation products are formed via nonenzymatic oxidation reactions.
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Affiliation(s)
- I Wiswedel
- Department of Dermatology and Venereology, Institute of Clinical Chemistry and Pathological Biochemistry, Otto-von-Guericke-University, Magdeburg, Germany.
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21
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Kumarathasan R, Leenen FHH. Effects of soybean lipoxygenase on Na+/K+-ATPase activity in vitro. Can J Physiol Pharmacol 2000. [DOI: 10.1139/y00-048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidized metabolites of polyunsaturated fatty acids produced by lipoxygenase are among the endogenous regulators of Na+/K+-ATPase. The direct effect of lipoxygenase on Na+/K+-ATPase activity was assessed in vitro using soybean lipoxygenase. Treatment of 4.2 µg/mL Na+/K+-ATPase (from dog kidneys) with 4.2 µg/mL of soybean lipoxygenase caused 20 ± 2% inhibition of ATPase activity. A 10-fold increase in lipoxygenase concentration (41.6 µg/mL) led to 30 ± 0.3% inhibition. In the presence of 12 µg/mL phenidone (a lipoxygenase inhibitor) and 15.4 µg/mL glutathione (a tripeptide containing a cysteine residue) inhibition of Na+/K+-ATPase activity was blocked and an increase in ATPase activity was observed. The presence of lipoxygenase enhanced the inhibition of Na+/K+-ATPase activity caused by 20 ng/mL ouabain (31 ± 2 vs. 19 ± 2) but had little or no effect with higher concentrations of ouabain. These findings suggest that lipoxygenase may regulate Na+/K+-ATPase by acting directly on the enzyme.Key words: Na+/K+-ATPase, soybean lipoxygenase, hypertension, oxidation, inhibition.
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Garrido R, Malecki A, Hennig B, Toborek M. Nicotine attenuates arachidonic acid-induced neurotoxicity in cultured spinal cord neurons. Brain Res 2000; 861:59-68. [PMID: 10751565 DOI: 10.1016/s0006-8993(00)01977-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Arachidonic acid release from cellular membranes due to spinal cord trauma may be one of the principal destructive events that can lead to progressive injury to spinal cord tissue. Exposure to arachidonic acid can compromise neuronal survival and viability. Because nicotine is known to be a neuroprotective agent, we propose that it can prevent arachidonic acid-induced neurotoxicity. To study this hypothesis, effects of nicotine on mitochondrial function, cellular energy content and apoptotic cell death were measured in cultured spinal cord neurons treated with arachidonic acid. Nicotine attenuated arachidonic acid-induced compromised cell viability and cellular ATP levels in spinal cord neurons. Nicotine exerted these protective effects when used at the concentration of 10 microM and only after a 2-h pre-treatment before a co-exposure to arachidonic acid. Antagonists of nicotinic receptors, such as alpha-bungarotoxin or mecamylamine, only partially reversed these neuroprotective effects of nicotine. In addition, nicotine prevented arachidonic acid-induced activation of caspase-3 activity and apoptotic cell death. These results indicate that nicotine pre-treatment can exert a protective effect against arachidonic acid-induced injury to spinal cord neurons.
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Affiliation(s)
- R Garrido
- Department of Surgery, Division of Neurosurgery, University of Kentucky Medical Center, Lexington, KY 40536, USA
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23
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Foley TD. The lipid peroxidation product 4-hydroxynonenal potently and selectively inhibits synaptic plasma membrane ecto-ATPase activity, a putative regulator of synaptic ATP and adenosine. Neurochem Res 1999; 24:1241-8. [PMID: 10492519 DOI: 10.1023/a:1020921006221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Synaptic plasma membrane (SPM)-bound, extracellular-facing (ecto) ATPases are Mg2+- or Ca2+-activated enzymes that regulate the synaptic levels of the excitatory neurotransmitter ATP and provide ADP for the further ecto-nucleotidase-mediated production of the inhibitory neuromodulator adenosine. The present results show that low concentrations (IC50 = 4 microM) of the lipid peroxidation product 4-hydroxynonenal (HNE) inhibited up to about 80% of the ecto-ATPase activity of SPM purified from rat brain cerebral cortex. In contrast, low concentrations of HNE did not inhibit the activity of the "intracellular"-facing Na+, K+, Mg2+-ATPase. In addition, the inhibition of SPM ecto-ATPase activity by HNE was largely irreversible and pH-dependent. Furthermore, structure-activity studies demonstrate that inhibition was dependent on the presence of the reactive functional groups of HNE. These findings suggest that HNE selectively inhibits SPM ecto-ATPase activity by a mechanism that may involve the covalent modification of functionally-critical nucleophilic amino acids. It is proposed that inhibition of SPM ecto-ATPase activity could contribute to the mechanisms by which lipid peroxidation and HNE formation promote excitotoxicity.
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Affiliation(s)
- T D Foley
- Section on Neurochemistry, LCS, DICBR, National Institute on Alcohol Abuse and Alcoholism, NIH, Rockville, MD 20852, USA.
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Chiba N, Imai H, Nakagawa Y. Determination of 5-hydroperoxyeicosatetraenoic acid produced in rat basophilic leukemia cell line RBL-2H3 by high-performance liquid chromatography with chemiluminescence detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 728:35-40. [PMID: 10379654 DOI: 10.1016/s0378-4347(99)00099-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A simple and sensitive method, applicable to quantification of 5-hydroperoxyeicosatetraenoic acid (5-HPETE) produced in cells has been developed using high-performance liquid chromatography on a silica gel column with chemiluminescence detection. 5-HPETE was clearly separated from other positional isomers of HPETEs and hydroxyeicosatetraenoic acids with hexane-isopropanol-acetic acid (97:3:0.01, v/v) as the mobile phase. The lower limit of detection was about 100 pg. 5-HPETE produced in 10(7) cells of RBL-2H3 cells stimulated with A23187 was determined as 480+/-30 pg. In the present study, 5-HPETE, which occurs naturally, was detected and quantitated for the first time in intact cells.
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Affiliation(s)
- N Chiba
- Japan Energy Research Center Co. Ltd., Tokyo
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25
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O'Flaherty JT, Taylor JS, Thomas MJ. Receptors for the 5-oxo class of eicosanoids in neutrophils. J Biol Chem 1998; 273:32535-41. [PMID: 9829988 DOI: 10.1074/jbc.273.49.32535] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
5-Hydroxy- and 5-oxo-eicosatetraenoate (5-HETE and 5-oxoETE) activate polymorphonuclear neutrophils (PMNs) through a common, receptor-like recognition system. To define this system, we examined the interaction of these eicosanoids with human PMNs. PMNs esterified 5-[3H]HETE to glycerolipids at 37 and 4 degreesC. At 37 but not 4 degreesC, the cells also hydroxylated the label to 5, 20-[3H]diHETE. The acyl:CoA synthetase blocker, triacsin C, inhibited esterification but also led to an increase in the hydroxylation of the label. PMNs processed 5-[3H]oxoETE through the same pathways but only or principally after reducing it to 5-[3H]HETE (37 or 4 degreesC). In the presence of these varying metabolic reactions, PMNs (37 or 4 degreesC; +/- triacsin C) could not be shown to receptor bind either radiolabel. Plasma membranes isolated from PMNs esterified but unlike whole cells did not reduce or hydroxylate 5-[3H]oxoETE. Triacsin C blocked esterification, thereby rendering the membranes unable to metabolize this radiolabel. Indeed, triacsin C-treated membranes bound (Kd = 3.8 nM) 5-[3H]oxoETE specifically and reversibly to 86 pmol of sites per 25 micrograms of membrane protein. 5-OxoETE, 5-HETE, and 5,15-diHETE displaced this binding at concentrations correlating with their potency in eliciting PMN Ca2+ transients. GTP and GTPgammaS, but not ATP or ATPgammaS, also reduced 5-[3H]oxoETE binding, whereas 15-HETE, leukotriene B4, platelet-activating factor, IL-8, C5a, and N-formyl-Met-Leu-Phe lacked this effect. We conclude that PMNs and their plasma membranes use an acyl:CoA synthetase-dependent route to esterify 5-HETE and 5-oxoETE into lipids. Blockade of the synthetase uncovers cryptic plasmalemma sites that bind 5-oxoETE with exquisite specificity. These sites apparently mediate responses to the 5-oxo class of eicosanoids and are likely members of the serpentine superfamily of G protein-linked receptors.
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Affiliation(s)
- J T O'Flaherty
- Departments of Internal Medicine, Wake Forest University Medical Center, Winston-Salem, North Carolina 27157, USA.
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Liu Y, Rosenthal RE, Haywood Y, Miljkovic-Lolic M, Vanderhoek JY, Fiskum G. Normoxic ventilation after cardiac arrest reduces oxidation of brain lipids and improves neurological outcome. Stroke 1998; 29:1679-86. [PMID: 9707212 DOI: 10.1161/01.str.29.8.1679] [Citation(s) in RCA: 154] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Increasing evidence that oxidative stress contributes to delayed neuronal death after global cerebral ischemia has led to reconsideration of the prolonged use of 100% ventilatory O2 following resuscitation from cardiac arrest. This study determined the temporal course of oxidation of brain fatty acyl groups in a clinically relevant canine model of cardiac arrest and resuscitation and tested the hypothesis that postischemic ventilation with 21% inspired O2, rather than 100% O2, results in reduced levels of oxidized brain lipids and decreased neurological impairment. METHODS Neurological deficit scoring and high performance liquid chromatography measurement of fatty acyl lipid oxidation were used in an established canine model using 10 minutes of cardiac arrest followed by resuscitation with different ventilatory oxygenation protocols and restoration of spontaneous circulation for 30 minutes to 24 hours. RESULTS Significant increases in frontal cortex lipid oxidation occurred after 10 minutes of cardiac arrest alone with no reperfusion and after reperfusion for 30 minutes, 2 hours, and 24 hours (relative total 235-nm absorbing peak areas=7.1+/-0.7 SE, 17.3+/-2.7, 14.2+/-3.2, 16.1+/-1.0, and 14.0+/-0.8, respectively; n=4, P<0.05). The predominant oxidized lipids were identified by gas chromatography/mass spectrometry as 13- and 9-hydroxyoctadecadienoic acids (13- and 9-HODE). Animals ventilated on 21% to 30% O2 versus 100% O2 for the first hour after resuscitation exhibited significantly lower levels of total and specific oxidized lipids in the frontal cortex (1.7+/-0.1 versus 3.12+/-0.78 microg 13-HODE/g wet wt cortex., n=4 to 6, P<0.05) and lower neurological deficit scores (45.1+/-3.6 versus 58.3+/-3.8, n=9, P<0.05). CONCLUSIONS With a clinically relevant canine model of 10 minutes of cardiac arrest, resuscitation with 21% versus 100% inspired O2 resulted in lower levels of oxidized brain lipids and improved neurological outcome measured after 24 hours of reperfusion. This study casts further doubt on the appropriateness of present guidelines that recommend the indiscriminate use of 100% ventilatory O2 for undefined periods during and after resuscitation from cardiac arrest.
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Affiliation(s)
- Y Liu
- Department of Biochemistry and Molecular Biology, The George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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