151
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Jeong EM, Ahn KH, Jeon HJ, Kim HD, Lee HS, Jung SY, Jung KM, Kim SK, Bonventre JV, Kim DK. Purification and characterization of a cytosolic Ca(2+)-independent phospholipase A(2) from bovine brain. Mol Cells 2011; 32:405-13. [PMID: 21874539 PMCID: PMC3887695 DOI: 10.1007/s10059-011-1058-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 06/13/2011] [Accepted: 07/01/2011] [Indexed: 02/02/2023] Open
Abstract
The Ca(2+)-independent phospholipase A(2) (iPLA(2)) subfamily of enzymes is associated with arachidonic acid (AA) release and the subsequent increase in fatty acid turnover. This phenomenon occurs not only during apoptosis but also during inflammation and lymphocyte proliferation. In this study, we purified and characterized a novel type of iPLA(2) from bovine brain. iPLA(2) was purified 4,174-fold from the bovine brain by a sequential process involving DEAE-cellulose anion exchange, phenyl-5PW hydrophobic interaction, heparin-Sepharose affinity, Sephacryl S-300 gel filtration, Mono S cation exchange, Mono Q anion exchange, and Superose 12 gel filtration. A single peak of iPLA(2) activity was eluted at an apparent molecular mass of 155 kDa during the final Superose 12 gel-filtration step. The purified enzyme had an isoelectric point of 5.3 on two-dimensional gel electrophoresis (2-DE) and was inhibited by arachidonyl trifluoromethyl ketone (AACOCF(3)), Triton X-100, iron, and Ca(2+). However, it was not inhibited by bromoenol lactone (BEL), an inhibitor of iPLA(2), and adenosine triphosphate (ATP). The spot with the iPLA(2) activity did not match with any known protein sequence, as determined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Altogether, these data suggest that the purified enzyme is a novel form of cytosolic iPLA(2).
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Affiliation(s)
| | | | | | | | | | | | | | | | - Joseph V. Bonventre
- Medical Services, Brigham and Women’s Hospital, Harvard Medical School, Boston, Longwood, MA, USA
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152
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Towards novel radiosensitizing agents: the role of cytosolic PLA2α in combined modality cancer therapy. Future Med Chem 2011; 3:835-43. [PMID: 21644828 DOI: 10.4155/fmc.11.38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The radioresistant nature of some tumors serves as an obstacle to curative therapy for several poor-prognosis malignancies. The radiosensitivity of a cancer is dependent not only on the intrinsic ability of tumor cells to recover from radiation-induced damage, but also the ability of stromal elements (e.g., vasculature) in the tumor microenvironment to survive and continue proliferating in the face of ionizing radiation. In this regard, it is important to understand the initial events activating radiation-induced signal transduction pathways. Among these events is the activation of cytosolic phospholipase A2 α and the subsequent production of the lipid second messengers. These events occur within minutes following exposure to ionizing radiation, and have been shown to enhance cell viability through a number of prosurvival signaling pathways. Furthermore, inhibition of cytosolic phospholipase A2 α has now been shown to reduce the viability of endothelial cells in culture after exposure to ionizing radiation, as well as slowing the growth of tumors in animal models of cancer.
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153
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Budsberg SC, Torres BT, Zwijnenberg RJ, Eppler CM, Clark JD, Cathcart CJ, Reynolds LR, Al-Nadaf S. Effect of perzinfotel and a proprietary phospholipase A(2) inhibitor on kinetic gait and subjective lameness scores in dogs with sodium urate-induced synovitis. Am J Vet Res 2011; 72:757-63. [PMID: 21627521 DOI: 10.2460/ajvr.72.6.757] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the ability of perzinfotel (an N-methyl-d-aspartate receptor antagonist) and a proprietary phospholipase A(2) (PLA(2)) inhibitor to attenuate lameness in dogs with sodium urate (SU)-induced synovitis. ANIMALS 8 adult dogs. PROCEDURES A blinded 4-way crossover study was performed. Dogs received perzinfotel (10 mg/kg), a proprietary PLA(2) inhibitor (10 mg/kg), carprofen (4.4 mg/kg; positive control treatment), or no treatment (negative control treatment). On the fourth day after initiation of treatment, synovitis was induced via intra-articular injection of SU 1 hour before administration of the last treatment dose. Ground reaction forces were measured and clinical lameness evaluations were performed before (baseline [time 0]) and 2, 4, 6, 8, 12, and 25 hours after SU injection. There was a 21-day washout period between subsequent treatments. Data were analyzed via repeated-measures ANOVAs. RESULTS Peak vertical force (PVF) and vertical impulse (VI) values for negative control and perzinfotel treatments were significantly lower at 2 and 4 hours, compared with baseline values. Values for PVF and VI for the PLA(2) inhibitor and positive control treatments did not differ from baseline values at any time points. Between-treatment comparisons revealed significantly higher PVF and VI values for the positive control treatment than for the negative control and perzinfotel treatments at 2 and 4 hours. Values for VI were higher for PLA(2) inhibitor treatment than for negative control treatment at 2 hours. CONCLUSIONS AND CLINICAL RELEVANCE Perzinfotel did not significantly alter SU-induced lameness. The proprietary PLA(2) inhibitor attenuated lameness but not as completely as did carprofen.
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Affiliation(s)
- Steven C Budsberg
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
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154
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Williams SP, Nowicki MO, Liu F, Press R, Godlewski J, Abdel-Rasoul M, Kaur B, Fernandez SA, Chiocca EA, Lawler SE. Indirubins decrease glioma invasion by blocking migratory phenotypes in both the tumor and stromal endothelial cell compartments. Cancer Res 2011; 71:5374-80. [PMID: 21697283 PMCID: PMC4288480 DOI: 10.1158/0008-5472.can-10-3026] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Invasion and proliferation in neoplasia require the cooperation of tumor cell and endothelial compartments. Glycogen synthase kinase-3 (GSK-3) is increasingly recognized as a major contributor to signaling pathways that modulate invasion and proliferation. Here we show that GSK-3 inhibitors of the indirubin family reduce invasion of glioma cells and glioma-initiating cell-enriched neurospheres both in vitro and in vivo, and we show that β-catenin signaling plays an important role in mediating these effects. Indirubins improved survival in glioma-bearing mice in which a substantial decrease in blood vessel density was seen in treated animals. In addition, indirubins blocked migration of endothelial cells, suggesting that anti-invasive glioma therapy with GSK-3 inhibitors in vivo not only inhibits invasion of tumor cells, but blocks migration of endothelial cells, which is also required for tumor angiogenesis. Overall, our findings suggest that indirubin inhibition of GSK-3 offers a novel treatment paradigm to target 2 of the most important interacting cellular compartments in heterotypic models of cancer.
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Affiliation(s)
- Shanté P. Williams
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | - Michal O. Nowicki
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | - Fang Liu
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | - Rachael Press
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | - Jakub Godlewski
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | | | - Balveen Kaur
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | | | - E. Antonio Chiocca
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
| | - Sean E. Lawler
- Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of Neurological Surgery, The Ohio State University Medical Center and James Comprehensive Cancer Center
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155
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Fabelo N, Martín V, Santpere G, Marín R, Torrent L, Ferrer I, Díaz M. Severe alterations in lipid composition of frontal cortex lipid rafts from Parkinson's disease and incidental Parkinson's disease. Mol Med 2011; 17:1107-18. [PMID: 21717034 DOI: 10.2119/molmed.2011.00119] [Citation(s) in RCA: 269] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 06/21/2011] [Indexed: 02/04/2023] Open
Abstract
Lipid rafts are cholesterol- and sphingomyelin-enriched microdomains that provide a highly saturated and viscous physicochemical microenvironment to promote protein-lipid and protein-protein interactions. We purified lipid rafts from human frontal cortex from normal, early motor stages of Parkinson's disease (PD) and incidental Parkinson's disease (iPD) subjects and analyzed their lipid composition. We observed that lipid rafts from PD and iPD cortices exhibit dramatic reductions in their contents of n-3 and n-6 long-chain polyunsaturated fatty acids, especially docosahexaenoic acid (22:6-n3) and arachidonic acid (20:4n-6). Also, saturated fatty acids (16:0 and 18:0) were significantly higher than in control brains. Paralleling these findings, unsaturation and peroxidability indices were considerably reduced in PD and iPD lipid rafts. Lipid classes were also affected in PD and iPD lipid rafts. Thus, phosphatidylserine and phosphatidylinositol were increased in PD and iPD, whereas cerebrosides and sulfatides and plasmalogen levels were considerably diminished. Our data pinpoint a dramatic increase in lipid raft order due to the aberrant biochemical structure in PD and iPD and indicate that these abnormalities of lipid rafts in the frontal cortex occur at early stages of PD pathology. The findings correlate with abnormal lipid raft signaling and cognitive decline observed during the development of these neurodegenerative disorders.
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Affiliation(s)
- Noemí Fabelo
- Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Tenerife, Spain
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156
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Vana AC, Li S, Ribeiro R, Tchantchou F, Zhang Y. Arachidonyl trifluoromethyl ketone ameliorates experimental autoimmune encephalomyelitis via blocking peroxynitrite formation in mouse spinal cord white matter. Exp Neurol 2011; 231:45-55. [PMID: 21683698 DOI: 10.1016/j.expneurol.2011.05.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 05/04/2011] [Accepted: 05/22/2011] [Indexed: 11/19/2022]
Abstract
Inhibition of phospholipase A(2) (PLA(2)) has recently been found to attenuate the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a commonly used animal model of multiple sclerosis (MS). However, the protective mechanisms that underlie PLA(2) inhibition are still not well understood. In this study, we found that cytosolic PLA(2) (cPLA(2)) was highly expressed in infiltrating lymphocytes and macrophages/microglia in mouse spinal cord white matter. Although cPLA(2) is also expressed in spinal cord neurons and oligodendrocytes, there were no differences observed in these cell types between EAE and control animals. Arachidonyl trifluoromethyl ketone (AACOCF3), a cPLA(2) inhibitor, significantly reduced the clinical symptoms and inhibited the body weight loss typically found in EAE mice. AACOCF3 also attenuated the loss of mature, myelin producing, oligodendrocytes, and axonal damage in the spinal cord white matter. Nitrotyrosine immunoreactivity, an indicator of peroxynitrite formation, was dramatically increased in EAE mice and attenuated by treatment with AACOCF3. These protective effects were not evident when AA861, an inhibitor of lipoxygenase, was used. In primary cultures of microglia, lipopolysaccharide (LPS) induced an upregulation of cPLA(2), inducible nitric oxide synthase (iNOS) and components of the NADPH oxidase complex, p47phox and p67phox. AACOCF3 significantly attenuated iNOS induction, nitric oxide production and the generation of reactive oxygen species in reactive microglia. Similar to the decomposition catalyst of peroxynitrite, AACOCF3 also blocked oligodendrocyte toxicity induced by reactive microglia. These results suggest that AACOCF3 may prevent oligodendrocyte loss in EAE by attenuating peroxynitrite formation in the spinal cord white matter.
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MESH Headings
- Animals
- Animals, Newborn
- Arachidonic Acids/pharmacology
- Arachidonic Acids/therapeutic use
- Cells, Cultured
- Coculture Techniques
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Mice
- Mice, Inbred C57BL
- Oligodendroglia/drug effects
- Oligodendroglia/metabolism
- Peroxynitrous Acid/antagonists & inhibitors
- Peroxynitrous Acid/metabolism
- Phospholipases A2, Cytosolic/antagonists & inhibitors
- Phospholipases A2, Cytosolic/physiology
- Rats
- Rats, Sprague-Dawley
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord/pathology
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Affiliation(s)
- Adam C Vana
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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157
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Bach JH, Jung KM, Choi JS, Jung SY, Chin MR, Ahn KH, Kim SK, Kim DK. Identification of a 42-kDa Group IV cPLA2-activating protein, cPLAPγ, as a GTP-binding protein in the bovine brain. J Biochem 2011; 150:385-94. [PMID: 21613292 DOI: 10.1093/jb/mvr064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brain tissue contains multiple forms of Phospholipase A(2) (PLA(2)) whose activities are involved in intracellular and intercellular signalling related to normal functions such as long-term potentiation, neurotransmitter release, cell growth and differentiation. Among them, we focused on regulatory mechanism of cPLA(2)α (Group IVA cytosolic PLA(2)) in brain tissue. In the present study, we report the identification of a cPLA(2)-activating protein (cPLAP) in the bovine brain. cPLAP activity appeared as two major peaks with molecular masses of 200 and 42 kDa in a Superose 12 gel filtration FPLC column. The 42-kDa form of cPLAP, designated cPLAPγ, was further purified using a Mono S FPLC column to near homogeneity and characterized to as a GTP-binding protein (G protein). Metabolic labelling and immunoprecipitation studies revealed that cPLAPγ associates with cPLA(2) in vitro and co-immunoprecipitates with [(35)S]-cPLA(2). Notably, cPLAPγ rendered cPLA(2) fully activated at submicromolar concentrations of Ca(2+). These results suggest that cPLAPγ may act as a G protein, activating cPLA(2)α prior to reaching full intracellular Ca(2+) concentrations.
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Affiliation(s)
- Jae Hyung Bach
- Department of Environmental & Health Chemistry, College of Pharmacy, Chung-Ang University, 221 Huksuk-dong, Dongjak-ku, Seoul 156-756, South Korea
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158
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Cytosolic phospholipase A2 as a molecular target for the radiosensitization of ovarian cancer. Cancer Lett 2011; 304:137-43. [PMID: 21397389 DOI: 10.1016/j.canlet.2011.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/10/2011] [Accepted: 02/15/2011] [Indexed: 12/14/2022]
Abstract
In ovarian cancer, the molecular targeted chemotherapeutics could increase the efficiency of low-dose radiotherapy while decreasing injury to adjusted organs. In irradiated A2780 human ovarian carcinoma cells, cytosolic phospholipase A2 (cPLA(2)) inhibitor AACOCF(3) prevented activation of pro-survival Akt signaling and enhanced cell death. The potential molecular mechanisms of this effect could involve signaling through lysophosphatidic acid receptors. In the heterotopic A2780 tumor model using nude mice, cPLA(2) inhibition significantly delayed tumor growth compared to treatment with radiation or vehicle alone. These results identify cPLA(2) as a molecular target to enhance the therapeutic ratio of radiation in ovarian cancer.
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159
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Rink C, Khanna S. Significance of brain tissue oxygenation and the arachidonic acid cascade in stroke. Antioxid Redox Signal 2011; 14:1889-903. [PMID: 20673202 PMCID: PMC3078506 DOI: 10.1089/ars.2010.3474] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The significance of the hypoxia component of stroke injury is highlighted by hypermetabolic brain tissue enriched with arachidonic acid (AA), a 22:6n-3 polyunsaturated fatty acid. In an ischemic stroke environment in which cerebral blood flow is arrested, oxygen-starved brain tissue initiates the rapid cleavage of AA from the membrane phospholipid bilayer. Once free, AA undergoes both enzyme-independent and enzyme-mediated oxidative metabolism, resulting in the formation of number of biologically active metabolites which themselves contribute to pathological stroke outcomes. This review is intended to examine two divergent roles of molecular dioxygen in brain tissue as (1) a substrate for life-sustaining homeostatic metabolism of glucose and (2) a substrate for pathogenic metabolism of AA under conditions of stroke. Recent developments in research concerning supplemental oxygen therapy as an intervention to correct the hypoxic component of stroke injury are discussed.
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Affiliation(s)
- Cameron Rink
- Department of Surgery, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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160
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Park JH, Hwang IC, Ha N, Lee S, Kim JM, Lee SS, Yu H, Lim IT, You JA, Kim DH. Effects of the anti-sepsis drug, (S)-1-(α-naphthylmethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD-712), on mortality, inflammation, and organ injuries in rodent sepsis models. Arch Pharm Res 2011; 34:485-94. [PMID: 21547682 DOI: 10.1007/s12272-011-0318-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 10/14/2010] [Accepted: 11/09/2010] [Indexed: 11/28/2022]
Abstract
CKD-712 is a 1-naphthyl analog of higenamine that has been reported to have potent antiinflammatory and thus anti-sepsis effects. The purpose of this study was to investigate the potential of CKD-712 as a medicine for sepsis and to confirm its protective effects on organs in animal sepsis models. Pretreatment with CKD-712 dose-dependently increased survival rate in a lipopolysaccharide-induced sepsis model in mice. Body temperature decrease, an important pre-symptom of septic death, was also prevented by CKD-712. CKD-712 still significantly increased survival rate even when administered one and four hours after lipopolysaccharide injection. Therapeutic efficacy of CKD-712 was also confirmed against sepsis following zymosan-induced endotoxemia and in cecal ligation and puncture surgery in mice. In a disseminated intravascular coagulation model in rats, CKD-712 showed organ-protective effect by reducing serum glutamate-oxaloacetate transaminase, glutamate-pyruvate transferase, blood urea nitrogen, and creatinine levels. CKD-712 also prevented histological damage to the lung and liver. In this same model, CKD-712 showed anti-inflammatory effects through decreases in tumor necrosis factor-α and interleukin-6 in the blood and reduced translocation of nuclear factor-κB to the nuclei of lung cells. CKD-712 administration also diminished infiltration of leukocytes into the lung and liver. Taken together, these results show that CKD-712 has excellent potential as an effective medicine for sepsis.
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Affiliation(s)
- Jae-Hwan Park
- Chong Kun Dang Research Institute, CKD Pharmaceuticals Inc., Chonan, Korea
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161
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Brustovetsky T, Brittain MK, Sheets PL, Cummins TR, Pinelis V, Brustovetsky N. KB-R7943, an inhibitor of the reverse Na+ /Ca2+ exchanger, blocks N-methyl-D-aspartate receptor and inhibits mitochondrial complex I. Br J Pharmacol 2011; 162:255-70. [PMID: 20883473 DOI: 10.1111/j.1476-5381.2010.01054.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE An isothiourea derivative (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methane sulfonate (KB-R7943), a widely used inhibitor of the reverse Na(+) /Ca(2+) exchanger (NCX(rev)), was instrumental in establishing the role of NCX(rev) in glutamate-induced Ca(2+) deregulation in neurons. Here, the effects of KB-R7943 on N-methyl-D-aspartate (NMDA) receptors and mitochondrial complex I were tested. EXPERIMENTAL APPROACH Fluorescence microscopy, electrophysiological patch-clamp techniques and cellular respirometry with Seahorse XF24 analyzer were used with cultured hippocampal neurons; membrane potential imaging, respirometry and Ca(2+) flux measurements were made in isolated rat brain mitochondria. KEY RESULTS KB-R7943 inhibited NCX(rev) with IC(50) = 5.7 ± 2.1 µM, blocked NMDAR-mediated ion currents, and inhibited NMDA-induced increase in cytosolic Ca(2+) with IC(50) = 13.4 ± 3.6 µM but accelerated calcium deregulation and mitochondrial depolarization in glutamate-treated neurons. KB-R7943 depolarized mitochondria in a Ca(2+) -independent manner. Stimulation of NMDA receptors caused NAD(P)H oxidation that was coupled or uncoupled from ATP synthesis depending on the presence of Ca(2+) in the bath solution. KB-R7943, or rotenone, increased NAD(P)H autofluorescence under resting conditions and suppressed NAD(P)H oxidation following glutamate application. KB-R7943 inhibited 2,4-dinitrophenol-stimulated respiration of cultured neurons with IC(50) = 11.4 ± 2.4 µM. With isolated brain mitochondria, KB-R7943 inhibited respiration, depolarized organelles and suppressed Ca(2+) uptake when mitochondria oxidized complex I substrates but was ineffective when mitochondria were supplied with succinate, a complex II substrate. CONCLUSIONS AND IMPLICATIONS KB-R7943, in addition to NCX(rev) , blocked NMDA receptors in cultured hippocampal neurons and inhibited complex I in the mitochondrial respiratory chain. These findings are critical for the correct interpretation of experimental results obtained with KB-R7943 and a better understanding of its neuroprotective action.
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Affiliation(s)
- Tatiana Brustovetsky
- Department of Pharmacology and Toxicology Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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162
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Askarova S, Yang X, Lee JCM. Impacts of membrane biophysics in Alzheimer's disease: from amyloid precursor protein processing to aβ Peptide-induced membrane changes. Int J Alzheimers Dis 2011; 2011:134971. [PMID: 21547213 PMCID: PMC3087431 DOI: 10.4061/2011/134971] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/30/2010] [Accepted: 01/21/2011] [Indexed: 12/11/2022] Open
Abstract
An increasing amount of evidence supports the notion that cytotoxic effects of amyloid-β peptide (Aβ), the main constituent of senile plaques in Alzheimer's disease (AD), are strongly associated with its ability to interact with membranes of neurons and other cerebral cells. Aβ is derived from amyloidogenic cleavage of amyloid precursor protein (AβPP) by β- and γ-secretase. In the nonamyloidogenic pathway, AβPP is cleaved by α-secretases. These two pathways compete with each other, and enhancing the non-amyloidogenic pathway has been suggested as a potential pharmacological approach for the treatment of AD. Since AβPP, α-, β-, and γ-secretases are membrane-associated proteins, AβPP processing and Aβ production can be affected by the membrane composition and properties. There is evidence that membrane composition and properties, in turn, play a critical role in Aβ cytotoxicity associated with its conformational changes and aggregation into oligomers and fibrils. Understanding the mechanisms leading to changes in a membrane's biophysical properties and how they affect AβPP processing and Aβ toxicity should prove to provide new therapeutic strategies for prevention and treatment of AD.
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Affiliation(s)
- Sholpan Askarova
- Department of Biological Engineering, University of Missouri, Columbia, MO 65211, USA
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163
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Zhao Z, Liu N, Huang J, Lu PH, Xu XM. Inhibition of cPLA2 activation by Ginkgo biloba extract protects spinal cord neurons from glutamate excitotoxicity and oxidative stress-induced cell death. J Neurochem 2011; 116:1057-65. [PMID: 21182525 DOI: 10.1111/j.1471-4159.2010.07160.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Ginkgo biloba extract (EGb761) has been shown to be neuroprotective; however, the mechanism by which EGb761 mediates neuroprotection remains unclear. We hypothesized that the neuroprotective effect of EGb761 is mediated by inhibition of cytosolic phospholipase A(2) (cPLA(2)), an enzyme that is known to play a key role in mediating secondary pathogenesis after acute spinal cord injury (SCI). To determine whether EGb761 neuroprotection involves the cPLA(2) pathway, we first investigated the effect of glutamate and hydrogen peroxide on cPLA(2) activation. Results showed that both insults induced an increase in the expression of phosphorylated cPLA(2) (p-cPLA(2)), a marker of cPLA(2) activation, and neuronal death in vitro. Such effects were significantly reversed by EGb761 administration. Additionally, EGb761 significantly decreased prostaglandin E(2) (PGE(2)) release, a downstream metabolite of cPLA(2). Moreover, inhibition of cPLA(2) activity with arachidonyl trifluromethyl ketone improved neuroprotection against glutamate and hydrogen peroxide-induced neuronal death, and reversed Bcl-2/Bax ratio; notably, EGb761 produced greater effects than arachidonyl trifluromethyl ketone. Finally, we showed that the extracellular signal-regulated kinase 1/2 signaling pathway is involved in EGb761's modulation of cPLA(2) phosphorylation. These results collectively suggest that the protective effect of EGb761 is mediated, at least in part, through inhibition of cPLA(2) activation, and that the extracellular signal-regulated kinase 1/2 signaling pathway may play an important role in mediating the EGb761's effect.
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Affiliation(s)
- Zhen Zhao
- Department of Neurobiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
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164
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Thwin M, Samy RP, Satyanarayanajois SD, Gopalakrishnakone P. Venom neutralization by purified bioactive molecules: Synthetic peptide derivatives of the endogenous PLA2 inhibitory protein PIP (a mini-review). Toxicon 2010; 56:1275-83. [DOI: 10.1016/j.toxicon.2009.12.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 12/17/2009] [Accepted: 12/21/2009] [Indexed: 01/06/2023]
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165
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Abstract
Depressive symptoms are common during pregnancy and the post-partum period. Although essential n-3 PUFA may have beneficial effects on depression, it remains unclear whether they are also effective for perinatal depression. The purpose of the present study was to assess the efficacy of n-3 supplementation for perinatal depression, by performing a meta-analysis on currently available data. After a thorough literature search, we included seven randomised controlled trials in the meta-analysis, all with EPA and/or DHA supplementation. Most studies were judged to be of low-to-moderate quality, mainly due to small sample sizes and failure to adhere to Consolidated Standards of Reporting Trials guidelines. Some studies were not primarily designed to address perinatal depression. A total of 309 women on n-3 fatty acid supplementation were compared with 303 women on placebo treatment. n-3 Supplementation was not found to be significantly more effective than placebo at post-treatment with a pooled effect size (Hedges's g) of - 0.03 (95 % CI - 0.18, 0.13; P = 0.76) using a fixed-effects model. Heterogeneity was low-to-moderate (I2 = 30 %). In a subgroup analysis of three small studies of pregnant women with major depression, there was some indication of effectiveness (effect size 0.17; 95 % CI - 0.21, 0.55). In conclusion, the question of whether EPA and DHA administration is effective in the prevention or treatment of perinatal depression cannot be answered yet. Future research should focus on women who are clinically depressed (or at risk). The quality of research in this area needs to improve.
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Kim HW, Rao JS, Rapoport SI, Igarashi M. Dietary n-6 PUFA deprivation downregulates arachidonate but upregulates docosahexaenoate metabolizing enzymes in rat brain. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1811:111-7. [PMID: 21070866 DOI: 10.1016/j.bbalip.2010.10.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 11/28/2022]
Abstract
BACKGROUND Dietary n-3 polyunsaturated fatty acid (PUFA) deprivation increases expression of arachidonic acid (AA 20:4n-6)-selective cytosolic phospholipase A(2) (cPLA(2)) IVA and cyclooxygenase (COX)-2 in rat brain, while decreasing expression of docosahexaenoic acid (DHA 22:6n-3)-selective calcium-independent iPLA(2) VIA. Assuming that these enzyme changes represent brain homeostatic responses to deprivation, we hypothesized that dietary n-6 PUFA deprivation would produce changes in the opposite directions. METHODS Brain expression of PUFA-metabolizing enzymes and their transcription factors was quantified in male rats fed an n-6 PUFA adequate or deficient diet for 15weeks post-weaning. RESULTS The deficient compared with adequate diet increased brain mRNA, protein and activity of iPLA(2) VIA and 15-lipoxygenase (LOX), but decreased cPLA(2) IVA and COX-2 expression. The brain protein level of the iPLA(2) transcription factor SREBP-1 was elevated, while protein levels were decreased for AP-2α and NF-κB p65, cPLA(2) and COX-2 transcription factors, respectively. CONCLUSIONS With dietary n-6 PUFA deprivation, rat brain PUFA metabolizing enzymes and some of their transcription factors change in a way that would homeostatically dampen reductions in brain n-6 PUFA concentrations and metabolism, while n-3 PUFA metabolizing enzyme expression is increased. The changes correspond to reported in vitro enzyme selectivities for AA compared with DHA.
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Affiliation(s)
- Hyung-Wook Kim
- National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
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Leonarduzzi G, Sottero B, Poli G. Targeting tissue oxidative damage by means of cell signaling modulators: The antioxidant concept revisited. Pharmacol Ther 2010; 128:336-74. [DOI: 10.1016/j.pharmthera.2010.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 08/02/2010] [Indexed: 12/25/2022]
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Docosahexaenoic acid suppresses neuroinflammatory responses and induces heme oxygenase-1 expression in BV-2 microglia: implications of antidepressant effects for ω-3 fatty acids. Neuropsychopharmacology 2010; 35:2238-48. [PMID: 20668435 PMCID: PMC3055314 DOI: 10.1038/npp.2010.98] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Accumulating evidence suggests that the pathophysiology of depression might be associated with neuroinflammation, which could be attenuated by pharmacological treatment for depression. Omega-3 polyunsaturated fatty acids (PUFAs) are anti-inflammatory and exert antidepressant effects. The aim of this study was to identify the molecular mechanisms through which docosahexaenoic acid (DHA), the main omega-3 PUFA in the brain, modulates oxidative reactions and inflammatory cytokine production in microglial and neuronal cells. The results of this study showed that DHA reduced expressions of tumor necrosis factor-α, interleukin-6, nitric oxide synthase, and cyclo-oxygenase-2, induced by interferon-γ, and induced upregulation of heme oxygenase-1 (HO-1) in BV-2 microglia. The inhibitory effect of DHA on nitric oxide production was abolished by HO-1 inhibitor zinc protoporphyrin IX. In addition, DHA caused AKT and ERK activation in a time-dependent manner, and the DHA-induced HO-1 upregulation could be attenuated by PI-3 kinase/AKT and MEK/ERK inhibitors. DHA also increased IKKα/β phosphorylation, IκBα phosphorylation, and IκBα degradation, whereas both nuclear factor-κB and IκB protease inhibitors could inhibit DHA-induced HO-1 expressions. The other major n-3 PUFA, eicosapentaenoic acid, showed similar effects of DHA on inflammation and HO-1 in repeated key experiments. In connecting with inflammation hypothesis of depression and clinical studies supporting the antidepressant effects of omega-3 PUFAs, this study provides a novel implication of the antidepressant mechanisms of DHA.
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Huang W, Bhavsar A, Ward RE, Hall JCE, Priestley JV, Michael-Titus AT. Arachidonyl trifluoromethyl ketone is neuroprotective after spinal cord injury. J Neurotrauma 2010; 26:1429-34. [PMID: 19371144 DOI: 10.1089/neu.2008.0835] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In spinal cord injury (SCI), neuronal and oligodendroglial loss occurs as a result of the initial trauma and the secondary damage that is triggered by excitotoxicity, free radicals, and inflammation. There is evidence that SCI ellicits increased cytosolic phospholipase A(2) (cPLA(2)) activity. The cleavage of phospholipids by cPLA(2) leads to release of fatty acids, and in particular arachidonic acid (AA), the metabolites of which have been associated with increased inflammation and oxidative stress. The aim of our study was to investigate whether the inhibition of cPLA(2) following SCI leads to tissue protection and an improved functional outcome. Adult rats received compression SCI and 30 min after injury they were treated intravenously with either saline or the cPLA(2) inhibitor arachidonyl trifluoromethyl ketone (AACOCF3) (7.13 mg/kg). The animals were sacrificed at 7 days post-injury and the lesioned tissue was labeled using markers for neurons, oligodendrocytes, and macrophages/activated microglia. We also assessed locomotor recovery using the Basso-Beattie-Bresnahan (BBB) score. The number of surviving neurons and oligodendrocytes was significantly increased in animals treated with the cPLA(2) inhibitor compared to saline controls. The behavioral analysis mirrored the neuroprotective effects and showed that the inhibitor-treated group had better locomotor recovery compared to saline controls. Our results show that AACOCF3 has neuroprotective potential, and support the idea that cPLA(2) is critically involved in acute spinal injury.
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Affiliation(s)
- Wenlong Huang
- Neuroscience Centre, Institute of Cell and Molecular Science, Barts and The London School of Medicine and Dentistry, London, United Kingdom
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170
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Tayebi M, David M, Bate C, Jones D, Taylor W, Morton R, Pollard J, Hawke S. Epitope-specific anti-prion antibodies upregulate apolipoprotein E and disrupt membrane cholesterol homeostasis. J Gen Virol 2010; 91:3105-15. [DOI: 10.1099/vir.0.023838-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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171
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Linkous AG, Yazlovitskaya EM, Hallahan DE. Cytosolic phospholipase A2 and lysophospholipids in tumor angiogenesis. J Natl Cancer Inst 2010; 102:1398-412. [PMID: 20729478 PMCID: PMC2943523 DOI: 10.1093/jnci/djq290] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background Lung cancer and glioblastoma multiforme are highly angiogenic and, despite advances in treatment, remain resistant to therapy. Cytosolic phospholipase A2 (cPLA2) activation contributes to treatment resistance through transduction of prosurvival signals. We investigated cPLA2 as a novel molecular target for antiangiogenesis therapy. Methods Glioblastoma (GL261) and Lewis lung carcinoma (LLC) heterotopic tumor models were used to study the effects of cPLA2 expression on tumor growth and vascularity in C57/BL6 mice wild type for (cPLA2α+/+) or deficient in (cPLA2α−/−) cPLA2α, the predominant isoform in endothelium (n = 6–7 mice per group). The effect of inhibiting cPLA2 activity on GL261 and LLC tumor growth was studied in mice treated with the chemical cPLA2 inhibitor 4-[2-[5-chloro-1-(diphenylmethyl)-2-methyl-1H-indol-3-yl]-ethoxy]benzoic acid (CDIBA). Endothelial cell proliferation and function were evaluated by Ki-67 immunofluorescence and migration assays in primary cultures of murine pulmonary microvascular endothelial cells (MPMEC) isolated from cPLA2α+/+ and cPLA2α−/− mice. Proliferation, invasive migration, and tubule formation were assayed in mouse vascular endothelial 3B-11 cells treated with CDIBA. Effects of lysophosphatidylcholine, arachidonic acid, and lysophosphatidic acid (lipid mediators of tumorigenesis and angiogenesis) on proliferation and migration were examined in 3B-11 cells and cPLA2α−/− MPMEC. All statistical tests were two-sided. Results GL261 tumor progression proceeded normally in cPLA2α+/+ mice, whereas no GL261 tumors formed in cPLA2α−/− mice. In the LLC tumor model, spontaneous tumor regression was observed in 50% of cPLA2α−/− mice. Immunohistochemical examination of the remaining tumors from cPLA2α−/− mice revealed attenuated vascularity (P ≤ .001) compared with tumors from cPLA2α+/+ mice. Inhibition of cPLA2 activity by CDIBA resulted in a delay in tumor growth (eg, LLC model: average number of days to reach tumor volume of 700 mm3, CDIBA vs vehicle: 16.8 vs 11.8, difference = 5, 95% confidence interval = 3.6 to 6.4, P = .04) and a decrease in tumor size (eg, GL261 model: mean volume on day 21, CDIBA vs vehicle: 40.1 vs 247.4 mm3, difference = 207.3 mm3, 95% confidence interval = 20.9 to 293.7 mm3, P = .021). cPLA2 deficiency statistically significantly reduced MPMEC proliferation and invasive migration (P = .002 and P = .004, respectively). Compared with untreated cells, cPLA2α−/− MPMEC treated with lysophosphatidylcholine and lysophosphatidic acid displayed increased cell proliferation (P = .011) and invasive migration (P < .001). Conclusions In these mouse models of brain and lung cancer, cPLA2 and lysophospholipids have key regulatory roles in tumor angiogenesis. cPLA2 inhibition may be a novel effective antiangiogenic therapy.
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Ramadan E, Rosa AO, Chang L, Chen M, Rapoport SI, Basselin M. Extracellular-derived calcium does not initiate in vivo neurotransmission involving docosahexaenoic acid. J Lipid Res 2010; 51:2334-40. [PMID: 20388940 PMCID: PMC2903827 DOI: 10.1194/jlr.m006262] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/13/2010] [Indexed: 11/20/2022] Open
Abstract
In vitro studies show that docosahexaenoic acid (DHA) can be released from membrane phospholipid by Ca(2+)-independent phospholipase A(2) (iPLA(2)), Ca(2+)-independent plasmalogen PLA(2) or secretory PLA(2 (sPLA2)), but not by Ca(2+)-dependent cytosolic PLA(2) (cPLA2), which selectively releases arachidonic acid (AA). Since glutamatergic NMDA (N-methyl-D-aspartate) receptor activation allows extracellular Ca(2+) into cells, we hypothesized that brain DHA signaling would not be altered in rats given NMDA, to the extent that in vivo signaling was mediated by Ca(2+)-independent mechanisms. Isotonic saline, a subconvulsive dose of NMDA (25 mg/kg), MK-801, or MK-801 followed by NMDA was administered i.p. to unanesthetized rats. Radiolabeled DHA or AA was infused intravenously and their brain incorporation coefficients k*, measures of signaling, were imaged with quantitative autoradiography. NMDA or MK-801 compared with saline did not alter k* for DHA in any of 81 brain regions examined, whereas NMDA produced widespread and significant increments in k* for AA. In conclusion, in vivo brain DHA but not AA signaling via NMDA receptors is independent of extracellular Ca(2+) and of cPLA(2). DHA signaling may be mediated by iPLA(2), plasmalogen PLA(2), or other enzymes insensitive to low concentrations of Ca(2+). Greater AA than DHA release during glutamate-induced excitotoxicity could cause brain cell damage.
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Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
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173
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A meta-analytic review of polyunsaturated fatty acid compositions in patients with depression. Biol Psychiatry 2010; 68:140-7. [PMID: 20452573 DOI: 10.1016/j.biopsych.2010.03.018] [Citation(s) in RCA: 367] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 03/09/2010] [Accepted: 03/10/2010] [Indexed: 01/21/2023]
Abstract
BACKGROUND On the basis of evidence from studies showing the antidepressant effects of omega-3 polyunsaturated fatty acids and the inverse relation between fish consumption and the prevalence of depression, the phospholipid hypothesis seems promising in ascertaining the etiology and treatment of depression. Although several studies have shown lower levels of omega-3 (n-3) polyunsaturated fatty acids in depressive patients, the results of individual polyunsaturated fatty acids, including docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and the omega-6 (n-6) polyunsaturated fatty acid arachidonic acid (AA), were inconsistent. METHODS We conducted the meta-analyses of 14 studies comparing the levels of polyunsaturated fatty acids between depressive patients and control subjects. The effect size of each study was synthesized by using a random effects model. RESULTS Compared with control subjects, the levels of EPA, DHA, and total n-3 polyunsaturated fatty acids were significantly lower in depressive patients. There was no significant change in AA or total n-6 polyunsaturated fatty acids. CONCLUSIONS The results showed lower levels of EPA, DHA, and total n-3 polyunsaturated fatty acids in patients with depression, thus implying that n-3 polyunsaturated fatty acids play a role in the pathogenesis of depression. Our findings provide further support to the phospholipid hypothesis of depression and a rationale for using n-3 polyunsaturated fatty acids as an alternative treatment for depression. With these results, future studies examining specific roles of DHA and EPA in different clusters of depressive symptoms are warranted.
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174
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Linkous A, Yazlovitskaya E. Cytosolic phospholipase A2 as a mediator of disease pathogenesis. Cell Microbiol 2010; 12:1369-77. [DOI: 10.1111/j.1462-5822.2010.01505.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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175
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Pasvogel AE, Miketova P, Moore IM. Differences in CSF phospholipid concentration by traumatic brain injury outcome. Biol Res Nurs 2010; 11:325-31. [PMID: 20338895 DOI: 10.1177/1099800409346056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality. A cascade of events is initiated with TBI that leads to degradation of the membrane lipid bilayer of neurons and neuroglia. The purpose of this study was to (a) describe changes in the cerebrospinal fluid (CSF) phospholipid concentration over time for those who survived and those who died following TBI; and (b) determine whether there were differences in the CSF phospholipid concentration between those who survived and those who died following TBI. Thirty-nine CSF samples were obtained from 10 participants who sustained a TBI. Following extraction, phospholipids were separated and quantified by normal-phase high performance liquid chromatography with ultraviolet detector. For those who died, the highest median concentration was on Day 1 after TBI for lysophosphatidylcholine and on Day 4 after TBI for phosphatidylethanolamine, phosphatidylserine, phosphatidylcholine, and sphingomyelin. For those who survived, the highest median concentration was on Day 1 after TBI for phosphatidylcholine, on Day 3 after TBI for phosphatidylethanolamine and phosphatidylserine, on Day 4 after TBI for sphingomyelin, and on Day 5 after TBI for lysophosphatidylcholine. There were significant differences in the concentrations of phosphatidylethanolamine and phosphatidylserine on Days 1-2 and of phosphatidylethanolamine, phosphatidylcholine, and sphingomyelin on Days 3-4 after TBI between those who survived and died, with the highest concentrations in those who died. These findings provide preliminary evidence of greater disruption of central nervous system membrane phospholipids in participants who died after TBI.
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Affiliation(s)
- Alice E Pasvogel
- College of Nursing, University of Arizona, 1305 N. Martin, Tucson, AZ 85721, USA.
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176
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Inhibitory effect of the natural product betulin and its derivatives against the intracellular bacterium Chlamydia pneumoniae. Biochem Pharmacol 2010; 80:1141-51. [PMID: 20615390 DOI: 10.1016/j.bcp.2010.06.051] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 06/28/2010] [Accepted: 06/29/2010] [Indexed: 11/22/2022]
Abstract
Chlamydia pneumoniae is a universal pathogen that has been indicated to play a part in the development of asthma, atherosclerosis and lung cancer. The complete eradication of this intracellular bacterium is in practice impossible with the antibiotics that are currently in use and studies on new antichlamydial compounds is challenging because Chlamydia research lacks the tools required for the genetic modification of this bacterium. Betulin is a natural lupane-class triterpene derived from plants with a wide variety of biological activities. This compound group thus has wide medical potentials, and in fact has been shown to be active against intracellular pathogens. For this reason, betulin and its derivatives were selected to be assayed against C. pneumoniae in the present study. Thirty-two betulin derivatives were assayed against C. pneumoniae using an acute infection model in vitro. Five promising compounds with potential lead compound characteristics were identified. Compound 24 (betulin dioxime) gave a minimal inhibitory concentration (MIC) of 1 microM against strain CWL-029 and showed activity in nanomolar concentrations, as 50% inhibition was achieved at 290 nM. The antichlamydial effect of 24 was confirmed with a clinical isolate CV-6, showing a MIC of 2.2 microM. Previous research on betulin and its derivatives has not identified such a remarkable inhibition of Gram-negative bacterial growth. Furthermore, we also demonstrated that this antichlamydial activity was not due to PLA(2) (EC 3.1.1.4) inhibition caused by the betulin derivatives.
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177
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Kaddurah-Daouk R, Baillie RA, Zhu H, Zeng ZB, Wiest MM, Nguyen UT, Watkins SM, Krauss RM. Lipidomic analysis of variation in response to simvastatin in the Cholesterol and Pharmacogenetics Study. Metabolomics 2010; 6:191-201. [PMID: 20445760 PMCID: PMC2862962 DOI: 10.1007/s11306-010-0207-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 03/04/2010] [Indexed: 11/06/2022]
Abstract
Statins are commonly used for reducing cardiovascular disease risk but therapeutic benefit and reductions in levels of low-density lipoprotein cholesterol (LDL-C) vary among individuals. Other effects, including reductions in C-reactive protein (CRP), also contribute to treatment response. Metabolomics provides powerful tools to map pathways implicated in variation in response to statin treatment. This could lead to mechanistic hypotheses that provide insight into the underlying basis for individual variation in drug response. Using a targeted lipidomics platform, we defined lipid changes in blood samples from the upper and lower tails of the LDL-C response distribution in the Cholesterol and Pharmacogenetics study. Metabolic changes in responders are more comprehensive than those seen in non-responders. Baseline cholesterol ester and phospholipid metabolites correlated with LDL-C response to treatment. CRP response to therapy correlated with baseline plasmalogens, lipids involved in inflammation. There was no overlap of lipids whose changes correlated with LDL-C or CRP responses to simvastatin suggesting that distinct metabolic pathways govern statin effects on these two biomarkers. Metabolic signatures could provide insights about variability in response and mechanisms of action of statins. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-010-0207-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Hongjie Zhu
- Department of Statistics and Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695-7566 USA
| | - Zhao-Bang Zeng
- Department of Statistics and Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695-7566 USA
| | - Michelle M. Wiest
- Lipomics Technologies-Tethys Bioscience, 3410 Industrial Boulevard, West Sacramento, CA 95691 USA
| | - Uyen Thao Nguyen
- Lipomics Technologies-Tethys Bioscience, 3410 Industrial Boulevard, West Sacramento, CA 95691 USA
| | - Steven M. Watkins
- Lipomics Technologies-Tethys Bioscience, 3410 Industrial Boulevard, West Sacramento, CA 95691 USA
| | - Ronald M. Krauss
- Children’s Hospital Oakland Research Institute, Oakland, CA 94609 USA
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178
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Liu NK, Xu XM. Phospholipase A2 and its molecular mechanism after spinal cord injury. Mol Neurobiol 2010; 41:197-205. [PMID: 20127525 PMCID: PMC9169014 DOI: 10.1007/s12035-010-8101-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 01/08/2010] [Indexed: 12/11/2022]
Abstract
Phospholipases A(2) (PLA(2)s) are a diverse family of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor which have been implicated in pathological states of numerous acute and chronic neurological disorders. To date, more than 27 isoforms of PLA(2) have been found in the mammalian system which can be classified into four major categories: secretory PLA(2), cytosolic PLA(2), Ca(2+)-independent PLA(2), and platelet-activating factor acetylhydrolases. Multiple isoforms of PLA(2) are found in the mammalian spinal cord. Under physiological conditions, PLA(2)s are involved in diverse cellular responses, including phospholipid digestion and metabolism, host defense, and signal transduction. However, under pathological situations, increased PLA(2) activity, excessive production of free fatty acids and their metabolites may lead to the loss of membrane integrity, inflammation, oxidative stress, and subsequent neuronal injury. There is emerging evidence that PLA(2) plays a key role in the secondary injury process after traumatic spinal cord injury. This review outlines the current knowledge of the PLA(2) in the spinal cord with an emphasis being placed on the possible roles of PLA(2) in mediating the secondary SCI.
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Affiliation(s)
- Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, 950 W. Walnut St., R-2 Building, Room 402, Indianapolis, IN 46202, USA
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179
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Alpha-synuclein, lipids and Parkinson's disease. Prog Lipid Res 2010; 49:420-8. [PMID: 20580911 DOI: 10.1016/j.plipres.2010.05.004] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 04/30/2010] [Indexed: 12/15/2022]
Abstract
Parkinson's disease is the second most common neurodegenerative disease, after Alzheimer's disease, among the aging human population. The main symptoms of Parkinson's disease such as tremor and movement disabilities are the result of degeneration of dopaminergic neurons in substantia nigra pars compacta. The widely-accepted subcellular factor which underlies Parkinson's disease neuropathology is the presence of Lewy bodies with characteristic inclusions of aggregated alpha-synuclein. This small soluble protein has been implicated in a range of interactions with phospholipid membranes and free fatty acids. The precise biological function of this protein is, however, still under investigation. Here we review the evidence linking alpha-synuclein, lipid metabolism, fatty acid oxidation, mitochondrial damage and Parkinson's disease. We propose that association of alpha-synuclein with oxidized lipid metabolites can lead to mitochondrial dysfunction in turn leading to dopaminergic neuron death and thus to Parkinson's disease.
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180
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Differential effects of lysophospholipids on exocytosis in rat PC12 cells. J Neural Transm (Vienna) 2010; 117:301-8. [PMID: 20058038 DOI: 10.1007/s00702-009-0355-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 12/01/2009] [Indexed: 10/20/2022]
Abstract
Secretory phospholipase A2 (sPLA2) activity is present in the CNS and the sPLA2-IIA isoform has been shown to induce exocytosis in cultured hippocampal neurons. However, little is known about possible contributions of various lysophospholipid species to exocytosis in neuroendocrine cells. This study was therefore carried out to examine the effects of several lysophospholipid species on exocytosis on rat pheochromocytoma-12 (PC12) cells. An increase in vesicle fusion, indicating exocytosis, was observed in PC12 cells after external infusion of lysophosphatidylinositol (LPI), but not lysophosphatidylcholine or lysophosphatidylserine by total internal reflection microscopy. Similarly, external infusion of LPI induced significant increases in capacitance, or number of spikes detected at amperometry, indicating exocytosis. Depletion of cholesterol by pre-incubation of cells with methyl beta cyclodextrin and depletion of Ca2+ by thapsigargin and incubation in zero external Ca2+ resulted in attenuation of LPI induced exocytosis, indicating that exocytosis was dependent on the integrity of lipid rafts and intracellular Ca2+. Moreover, LPI induced a rise in intracellular Ca2+ suggesting that this could be the trigger for exocytosis. It is postulated that LPI may be an active participant in sPLA2-mediated exocytosis in the CNS.
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181
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Kirkby B, Roman N, Kobe B, Kellie S, Forwood JK. Functional and structural properties of mammalian acyl-coenzyme A thioesterases. Prog Lipid Res 2010; 49:366-77. [PMID: 20470824 DOI: 10.1016/j.plipres.2010.04.001] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
Acyl-coenzyme A thioesterases (Acots) play important cellular roles in mammalian fatty acid metabolism through modulation of cellular concentrations of activated fatty acyl-CoAs. Acots catalyse the hydrolysis of the thioester bond present within acyl-CoA ester molecules to yield coenzyme A (CoASH) and the corresponding non-esterified fatty acid. Acyl-CoA thioesterases are expressed ubiquitously in both prokaryotes and eukaryotes and, in higher order organisms, the enzymes are expressed and localised in a tissue-dependent manner within the cytosol, mitochondria, peroxisomes and endoplasmic reticulum. Recent studies have led to advances in the functional and structural characterization of many mammalian Acot family members. These include the structure determination of both type-I and type-II Acot family members, structural elucidation of the START domain of ACOT11, identification of roles in arachidonic acid and inflammatory prostaglandin production by Acot7, and inclusion of a 13th Acot family member. Here, we review and analyse the current literature on mammalian Acots with respect to their characterization and summarize the current knowledge on the structure, function and regulation of this enzyme family.
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Affiliation(s)
- Brenda Kirkby
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW 2650, Australia
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182
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Ha SW, Lee CS. Differential effect of platelet activating factor on 1-methyl-4-phenylpyridinium-induced cell death through regulation of apoptosis-related protein activation. Neurochem Int 2010; 56:819-28. [DOI: 10.1016/j.neuint.2010.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 03/10/2010] [Accepted: 03/12/2010] [Indexed: 11/27/2022]
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183
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Membrane biophysics and mechanics in Alzheimer's disease. Mol Neurobiol 2010; 41:138-48. [PMID: 20437210 DOI: 10.1007/s12035-010-8121-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 03/17/2010] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease is a chronic neurodegenerative disorder characterized by neuronal loss, cerebrovascular inflammation, and accumulation of senile plaques in the brain parenchyma and cerebral blood vessels. Amyloid-beta peptide (Abeta), a major component of senile plaques, has been shown to exert multiple toxic effects to neurons, astrocytes, glial cells, and brain endothelium. Oligomeric Abeta can disturb the structure and function of cell membranes and alter membrane mechanical properties, such as membrane fluidity and molecular order. Much of these effects are attributed to their capability to trigger oxidative stress and inflammation. In this review, we discuss the effects of Abeta on neuronal cells, astrocytes, and cerebral endothelial cells with special emphasis on cell membrane properties and cell functions.
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184
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Floreani NA, Rump TJ, Abdul Muneer PM, Alikunju S, Morsey BM, Brodie MR, Persidsky Y, Haorah J. Alcohol-induced interactive phosphorylation of Src and toll-like receptor regulates the secretion of inflammatory mediators by human astrocytes. J Neuroimmune Pharmacol 2010; 5:533-45. [PMID: 20379791 DOI: 10.1007/s11481-010-9213-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 03/15/2010] [Indexed: 01/20/2023]
Abstract
Secretion of pro-inflammatory molecules by astrocytes after alcohol treatment was shown to be associated with neuroinflammation. We hypothesized that activation of cytosolic phospholipase A2 (cPLA2) and cyclooxygenase (COX-2) by ethanol in astrocytes enhanced the secretion of inflammatory agents via the interactive tyrosine phosphorylation of toll-like receptor 4 (TLR4) and Src kinase. To test this hypothesis, we treated primary human astrocytes with 20 mM ethanol for 48 h at 37°C. Ethanol exposure elevated cytochrome P450-2E1 activity, reactive oxygen species levels, and secretion of prostaglandin E2 (PGE2) in these cells. Secretion of PGE2 was associated with induction of cPLA2 activity and protein content as well as COX-2 protein level in a Src phosphorylation-dependent manner that occurred by enhanced transcription. Immunoprecipitation and Western blot analyses indicated that the interactive tyrosine phosphorylation of TLR4-Src complex at the cell membrane triggered the activation of cPLA2 and COX-2 in the cytoplasm through a Src signaling intermediate. Inhibition of ethanol metabolism, blockage of Src activity, or inactivation of TLR4 prevented the activation of cPLA2 and COX-2 as well as diminished PGE2 production, suggesting that interactive phosphorylation of TLR4-Src regulated the pro-inflammatory response in astrocytes. Experiments with small interfering RNA knockdown of TLR4 in human astrocytes confirmed that silencing expression also abolished the interactive phosphorylation of both TLR4 and Src in the presence of ethanol.
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Affiliation(s)
- Nicholas A Floreani
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5215, USA
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185
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Goracci G, Ferrini M, Nardicchi V. Low Molecular Weight Phospholipases A2 in Mammalian Brain and Neural Cells: Roles in Functions and Dysfunctions. Mol Neurobiol 2010; 41:274-89. [DOI: 10.1007/s12035-010-8108-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 02/11/2010] [Indexed: 12/14/2022]
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186
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Horstman LL, Jy W, Ahn YS, Zivadinov R, Maghzi AH, Etemadifar M, Steven Alexander J, Minagar A. Role of platelets in neuroinflammation: a wide-angle perspective. J Neuroinflammation 2010; 7:10. [PMID: 20128908 PMCID: PMC2829540 DOI: 10.1186/1742-2094-7-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 02/03/2010] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES This review summarizes recent developments in platelet biology relevant to neuroinflammatory disorders. Multiple sclerosis (MS) is taken as the "Poster Child" of these disorders but the implications are wide. The role of platelets in inflammation is well appreciated in the cardiovascular and cancer research communities but appears to be relatively neglected in neurological research. ORGANIZATION After a brief introduction to platelets, topics covered include the matrix metalloproteinases, platelet chemokines, cytokines and growth factors, the recent finding of platelet PPAR receptors and Toll-like receptors, complement, bioactive lipids, and other agents/functions likely to be relevant in neuroinflammatory diseases. Each section cites literature linking the topic to areas of active research in MS or other disorders, including especially Alzheimer's disease. CONCLUSION The final section summarizes evidence of platelet involvement in MS. The general conclusion is that platelets may be key players in MS and related disorders, and warrant more attention in neurological research.
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Affiliation(s)
- Lawrence L Horstman
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Wenche Jy
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Yeon S Ahn
- Wallace Coulter Platelet Laboratory, Division of Hematology and Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, The Jacobs Neurological Institute, Department of Neurology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo NY, USA
| | - Amir H Maghzi
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Masoud Etemadifar
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - J Steven Alexander
- Department of Cellular and Molecular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
| | - Alireza Minagar
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA
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187
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Farooqui AA. Studies on plasmalogen-selective phospholipase A2 in brain. Mol Neurobiol 2010; 41:267-73. [PMID: 20049656 DOI: 10.1007/s12035-009-8091-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Accepted: 12/04/2009] [Indexed: 12/24/2022]
Abstract
Plasmalogen-selective phospholipase A(2) (PlsEtn-PLA(2)) has been purified from pig brain using multiple column chromatographic procedure. The purified enzyme migrates as a single band on polyacrylamide. It is stimulated by Triton X-100 and inhibited by sodium deoxycholate. Purified PlsEtn-PLA(2) is inhibited by iodoacetate, and this inhibition can be prevented by beta-meracaptoethanol. Treatment of neuronal cell cultures with kainic acid stimulates PlsEtn-PLA(2) activity in a dose-dependent manner, and this stimulation can be blocked by Ly294486, a selective kainic acid receptor antagonist. Activities of PlsEtn-PLA(2) are markedly increased in plasma membrane and synaptosomal plasma membrane fraction prepared from nucleus basalis and hippocampal region of brains from Alzheimer disease patients compared to age-matched controls. It is proposed that accumulation of ceramide and increased expression of cytokines may be responsible for the stimulation of PlsEtn-PLA(2) in Alzheimer disease.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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188
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Adibhatla RM, Hatcher JF. Lipid oxidation and peroxidation in CNS health and disease: from molecular mechanisms to therapeutic opportunities. Antioxid Redox Signal 2010; 12:125-69. [PMID: 19624272 DOI: 10.1089/ars.2009.2668] [Citation(s) in RCA: 317] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reactive oxygen species (ROS) are produced at low levels in mammalian cells by various metabolic processes, such as oxidative phosphorylation by the mitochondrial respiratory chain, NAD(P)H oxidases, and arachidonic acid oxidative metabolism. To maintain physiological redox balance, cells have endogenous antioxidant defenses regulated at the transcriptional level by Nrf2/ARE. Oxidative stress results when ROS production exceeds the cell's ability to detoxify ROS. Overproduction of ROS damages cellular components, including lipids, leading to decline in physiological function and cell death. Reaction of ROS with lipids produces oxidized phospholipids, which give rise to 4-hydroxynonenal, 4-oxo-2-nonenal, and acrolein. The brain is susceptible to oxidative damage due to its high lipid content and oxygen consumption. Neurodegenerative diseases (AD, ALS, bipolar disorder, epilepsy, Friedreich's ataxia, HD, MS, NBIA, NPC, PD, peroxisomal disorders, schizophrenia, Wallerian degeneration, Zellweger syndrome) and CNS traumas (stroke, TBI, SCI) are problems of vast clinical importance. Free iron can react with H(2)O(2) via the Fenton reaction, a primary cause of lipid peroxidation, and may be of particular importance for these CNS injuries and disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Atherosclerosis, the major risk factor for ischemic stroke, involves accumulation of oxidized LDL in the arteries, leading to foam cell formation and plaque development. This review will discuss the role of lipid oxidation/peroxidation in various CNS injuries/disorders.
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Affiliation(s)
- Rao Muralikrishna Adibhatla
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792-3232, USA.
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189
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Phospholipase A2-derived lysophosphatidylcholine triggers Ca2+ entry in dystrophic skeletal muscle fibers. Biochem Biophys Res Commun 2010; 391:401-6. [DOI: 10.1016/j.bbrc.2009.11.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 11/10/2009] [Indexed: 11/24/2022]
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Bate C, Tayebi M, Diomede L, Salmona M, Williams A. Glimepiride reduces the expression of PrPc, prevents PrPSc formation and protects against prion mediated neurotoxicity in cell lines. PLoS One 2009; 4:e8221. [PMID: 20011040 PMCID: PMC2784943 DOI: 10.1371/journal.pone.0008221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 11/11/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND A hallmark of the prion diseases is the conversion of the host-encoded cellular prion protein (PrP(C)) into a disease related, alternatively folded isoform (PrP(Sc)). The accumulation of PrP(Sc) within the brain is associated with synapse loss and ultimately neuronal death. Novel therapeutics are desperately required to treat neurodegenerative diseases including the prion diseases. PRINCIPAL FINDINGS Treatment with glimepiride, a sulphonylurea approved for the treatment of diabetes mellitus, induced the release of PrP(C) from the surface of prion-infected neuronal cells. The cell surface is a site where PrP(C) molecules may be converted to PrP(Sc) and glimepiride treatment reduced PrP(Sc) formation in three prion infected neuronal cell lines (ScN2a, SMB and ScGT1 cells). Glimepiride also protected cortical and hippocampal neurones against the toxic effects of the prion-derived peptide PrP82-146. Glimepiride treatment significantly reduce both the amount of PrP82-146 that bound to neurones and PrP82-146 induced activation of cytoplasmic phospholipase A(2) (cPLA(2)) and the production of prostaglandin E(2) that is associated with neuronal injury in prion diseases. Our results are consistent with reports that glimepiride activates an endogenous glycosylphosphatidylinositol (GPI)-phospholipase C which reduced PrP(C) expression at the surface of neuronal cells. The effects of glimepiride were reproduced by treatment of cells with phosphatidylinositol-phospholipase C (PI-PLC) and were reversed by co-incubation with p-chloromercuriphenylsulphonate, an inhibitor of endogenous GPI-PLC. CONCLUSIONS Collectively, these results indicate that glimepiride may be a novel treatment to reduce PrP(Sc) formation and neuronal damage in prion diseases.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, North Mymms, United Kingdom.
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191
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Choi YS, Jeong YS, Ok SH, Shin IW, Lee SH, Park JY, Hwang EM, Hah YS, Sohn JT. The direct effect of levobupivacaine in isolated rat aorta involves lipoxygenase pathway activation and endothelial nitric oxide release. Anesth Analg 2009; 110:341-9. [PMID: 19955508 DOI: 10.1213/ane.0b013e3181c76f52] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Levobupivacaine is a long-acting local anesthetic with a clinical profile similar to that of racemic bupivacaine but with a greater margin of safety. Levobupivacaine produces dose-dependent vasoconstriction in vivo. Our goal in this in vitro study was to investigate the role of pathways involved in arachidonic acid metabolism in the levobupivacaine-induced contraction of isolated rat aorta and to determine which endothelium-derived vasodilators are involved in the modulation of levobupivacaine-induced contraction. METHODS Rat thoracic aortic rings were isolated and suspended for isometric tension recording. Cumulative levobupivacaine dose-response curves over a range of 10(-6) to 3 x 10(-4) M were constructed in 1) aortic rings with no drug pretreatment; 2) endothelium-denuded rings pretreated with quinacrine dihydrochloride (nonspecific phospholipase A(2) inhibitor: 2 x 10(-5), 4 x 10(-5) M), nordihydroguaiaretic acid (NDGA) (lipoxygenase inhibitor: 10(-5), 3 x 10(-5) M), indomethacin (nonspecific cyclooxygenase inhibitor: 10(-5) M), AA-861 (5-lipoxygenase inhibitor: 10(-5), 5 x 10(-5) M), fluconazole (cytochrome P450 epoxygenase inhibitor: 10(-5) M), verapamil (10(-5) M), or calcium-free solution; and 3) endothelium-intact rings pretreated with N(omega)-nitro-L-arginine methyl ester (L-NAME) (nitric oxide synthase inhibitor: 5 x 10(-5) M), indomethacin, or fluconazole. Levobupivacaine-induced contractile response at each concentration (10(-4), 3 x 10(-4) M) was assessed in endothelium-denuded rings. Dose-response curves for potassium chloride in endothelium-denuded rings were generated in the presence or absence of NDGA and AA-861. Intracellular Ca(2+) levels were monitored by Ca(2+) image analysis using Fluo-4 fluorescence in vascular smooth muscle cells treated with levobupivacaine alone or AA-861 plus levobupivacaine. RESULTS Levobupivacaine produced a tonic contraction in isolated rat aorta rings; this response was maximal at 10(-4) M levobupivacaine and gradually attenuated at 3 x 10(-4) M levobupivacaine. Levobupivacaine-induced contractions of endothelium-denuded rings were larger than those of endothelium-intact rings. Levobupivacaine-induced contraction of endothelium-denuded rings was attenuated by quinacrine dihydrochloride, NDGA, AA-861, verapamil, and calcium-free solution and, to a lesser extent, by indomethacin. L-NAME enhanced levobupivacaine-induced contraction of endothelium-intact rings and indomethacin slightly attenuated this contraction. NDGA and AA-861 attenuated the potassium chloride-induced contraction. AA-861 attenuated the levobupivacaine-induced intracellular calcium increase in vascular smooth muscle cells. CONCLUSIONS Our data indicate that levobupivacaine-induced contraction of rat aortic smooth muscle is mediated mainly by activation of the lipoxygenase pathway and in part by activation of the cyclooxygenase pathway. In addition, activation of the lipoxygenase pathway seems to facilitate calcium influx via L-type calcium channels. Endothelial nitric oxide attenuates levobupivacaine-induced contraction.
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Affiliation(s)
- Yun Suk Choi
- Department of Anesthesiology and Pain Medicine, Gyeongsang National University Hospital, Jinju 660-702, Republic of Korea.
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192
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Red blood cell plasmalogens and docosahexaenoic acid are independently reduced in primary open-angle glaucoma. Exp Eye Res 2009; 89:840-53. [DOI: 10.1016/j.exer.2009.07.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 07/15/2009] [Accepted: 07/15/2009] [Indexed: 11/21/2022]
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193
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van Rensburg SJ, Smuts CM, Hon D, Kidd M, van der Merwe S, Myburgh C, Oosthuizen P, Emsley R. Changes in erythrocyte membrane fatty acids during a clinical trial of eicosapentaenoic acid (EPA) supplementation in schizophrenia. Metab Brain Dis 2009; 24:659-72. [PMID: 19826937 DOI: 10.1007/s11011-009-9160-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Accepted: 08/29/2009] [Indexed: 01/13/2023]
Abstract
In a previously reported double-blind, placebo-controlled trial of eicosapentaenoic acid (EPA) as supplemental treatment in 40 patients with schizophrenia, we found significant improvement in symptoms as measured by the Positive and Negative Syndrome Scale (PANSS) compared to placebo (Emsley et al. 2002). Here we report changes in fatty acid composition of erythrocyte membranes in the same sample (n = 16 in each group). After 12 weeks of receiving EPA, levels of several saturated and mono-unsaturated fatty acids decreased significantly while levels of n-3 fatty acids increased significantly compared to the placebo group. Increases of n-3 and n-6 fatty acids in the erythrocyte membranes were greater in subjects who improved more than 20% on overall symptoms. Changes in fatty acids correlated significantly with improvement in PANSS sub-scale scores, more so in females than in males. Docosahexaenoic acid (DHA) (22:6n-3) levels increased less than expected, suggesting a possible defect in synthesis or incorporation of DHA into membranes in schizophrenia. Improvement in dyskinesia correlated significantly with an increase in alpha-linolenic acid (18:3n-3; p = 0.03), and a decrease in 20:1n-9 (p = 0.005).
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Affiliation(s)
- Susan J van Rensburg
- Division of Chemical Pathology, National Health Laboratory Service, University of Stellenbosch, Stellenbosch, South Africa.
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194
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Lessig J, Fuchs B. HOCl-mediated glycerophosphocholine and glycerophosphoethanolamine generation from plasmalogens in phospholipid mixtures. Lipids 2009; 45:37-51. [PMID: 19937395 DOI: 10.1007/s11745-009-3365-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 07/03/2009] [Indexed: 11/30/2022]
Abstract
Many mammalian tissues and cells contain, in addition to (diacyl) phospholipids, considerable amounts of plasmalogens, which may function as important antioxidants. Apart from the "scavenger" function mediated by the high sensitivity of the vinyl-ether bond, the functional role of plasmalogens is so far widely unknown. Furthermore, there is increasing evidence that plasmalogen degradation products have harmful effects in inflammatory processes. In a previous investigation glycerophosphocholine (GPC) formation was verified as a novel plasmalogen degradation pathway upon oxidation with hypochlorous acid (HOCl), however these investigations were performed in simple model systems. Herein, we examine plasmalogen degradation in a more complex system in order to evaluate if GPC generation is also a major pathway in the presence of other highly unsaturated glycerophospholipids (GPL) representing an additional reaction site of HOCl targets. Using MALDI-TOF mass spectrometry and (31)P NMR spectroscopy, we confirmed that the first step of the HOCl-induced degradation of GPL mixtures containing plasmalogens is the attack of the vinyl-ether bond resulting in the generation of 1-lysophosphatidylcholine (lysoPtdCho) or 1-lysophosphatidylethanolamine. In the second step HOCl reacts with the fatty acyl residue in the sn-2 position of 1-lysoPtdCho. This reaction is about three times faster in comparison to comparable diacyl-GPL. Thus, the generation of GPC and glycerophosphoethanolamine (GPE) from plasmalogens are relevant products formed from HOCl attack on the vinyl-ether bond of plasmalogens under pathological conditions.
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Affiliation(s)
- Jacqueline Lessig
- Medical Faculty, Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
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195
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Sun GY, Shelat PB, Jensen MB, He Y, Sun AY, Simonyi A. Phospholipases A2 and inflammatory responses in the central nervous system. Neuromolecular Med 2009; 12:133-48. [PMID: 19855947 DOI: 10.1007/s12017-009-8092-z] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 09/25/2009] [Indexed: 12/21/2022]
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolyzing the sn-2 fatty acids of membrane phospholipids. These enzymes are known to play multiple roles for maintenance of membrane phospholipid homeostasis and for production of a variety of lipid mediators. Over 20 different types of PLA2s are present in the mammalian cells, and in snake and bee venom. Despite their common function in hydrolyzing fatty acids of phospholipids, they are diversely encoded by a number of genes and express proteins that are regulated by different mechanisms. Recent studies have focused on the group IV calcium-dependent cytosolic cPLA2, the group VI calcium-independent iPLA2, and the group II small molecule secretory sPLA2. In the central nervous system (CNS), these PLA2s are distributed among neurons and glial cells. Although the physiological role of these PLA2s in regulating neural cell function has not yet been clearly elucidated, there is increasing evidence for their involvement in receptor signaling and transcriptional pathways that link oxidative events to inflammatory responses that underline many neurodegenerative diseases. Recent studies also reveal an important role of cPLA2 in modulating neuronal excitatory functions, sPLA2 in the inflammatory responses, and iPLA2 with childhood neurologic disorders associated with brain iron accumulation. The goal for this review is to better understand the structure and function of these PLA2s and to highlight specific types of PLA2s and their cross-talk mechanisms in these inflammatory responses under physiological and pathological conditions in the CNS.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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196
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Chalbot S, Zetterberg H, Blennow K, Fladby T, Grundke-Iqbal I, Iqbal K. Cerebrospinal fluid secretory Ca2+-dependent phospholipase A2 activity is increased in Alzheimer disease. Clin Chem 2009; 55:2171-9. [PMID: 19850632 DOI: 10.1373/clinchem.2009.130286] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The phospholipase A(2) (PLA2) family comprises multiple isoenzymes that vary in their physicochemical properties, cellular localizations, calcium sensitivities, and substrate specificities. Despite these differences, PLA2s share the ability to catalyze the synthesis of the precursors of the proinflammatory mediators. To investigate the potential of PLA2 as a biomarker in screening neuroinflammatory disorders in both clinical and research settings, we developed a PLA2 assay and determined the predominant types of PLA2 activity in cerebrospinal fluid (CSF). METHODS We used liposomes composed of a fluorescent probe (bis-Bodipy FL C11-PC [1,2-bis-(4,4- difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-undecanoyl)-sn-glycero-3-phosphocholine]) and 1,2-dioleoyl-l-alpha-phosphatidylcholine as a substrate to measure CSF PLA2 activity in a 96-well microtiter plate format. We established the type of CSF PLA2 activity using type-specific inhibitors of PLA2. RESULTS Using 5 microL CSF per assay, our PLA2 activity assay was reproducible with CVs <15% in 2 CSF samples and for recombinant secretory Ca(2+)-dependent PLA2 (sPLA2) in concentrations ranging from 0.25 to 1 micromol/L. This PLA2 assay allowed identification of sPLA2 activity in lumbar CSF from healthy individuals 20-77 years old that did not depend on either sex or age. Additionally, CSF sPLA2 activity was found to be increased (P = 0.0008) in patients with Alzheimer disease. CONCLUSIONS Adult human CSF has sPLA2 activity that can be measured reliably with the assay described. This enzyme activity in the CSF is independent of both sex and age and might serve as a valuable biomarker of neuroinflammation, as we demonstrated in Alzheimer disease.
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Affiliation(s)
- Sonia Chalbot
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314-6399, USA
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197
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Mathur A, Law MH, Hamzehloei T, Megson IL, Shaw DJ, Wei J. No association between the PPARG gene and schizophrenia in a British population. Prostaglandins Leukot Essent Fatty Acids 2009; 81:273-7. [PMID: 19560328 DOI: 10.1016/j.plefa.2009.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/22/2009] [Accepted: 06/04/2009] [Indexed: 11/17/2022]
Abstract
It has consistently been reported that patients with schizophrenia have an increased risk of type-2 diabetes. To investigate a genetic link between these two diseases, the combined effects of the PLA2G4A, PTGS2 and PPARG genes were tested among 221 British nuclear families consisting of fathers, mothers and affected offspring with schizophrenia. A total of 10 single nucleotide polymorphisms (SNPs) were tested and the likelihood-based association analysis for nuclear families was used to analyse the genotyping data. Eight SNPs detected across the PPARG gene did not show allelic association with schizophrenia; a weak association was detected at rs2745557 in the PTGS2 locus (chi2=4.19, p=0.041) and rs10798059 in the PLA2G4A locus (chi2=4.28, p=0.039) but these associations did not survive after 10,000 permutations to correct the p-value (global p=0.246). The gene-gene interaction test did not show any evidence of either cis-phase interactions for the PLA2G4A and PTGS2 combinations or a trans-phase interaction for the PLA2G4A and PPARG combinations. The PPARG gene has been reported to be strongly associated with type-2 diabetes, but the present study did not support the hypothesis that the PPARG gene may also play an important role in the development of schizophrenia.
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Affiliation(s)
- Aditi Mathur
- The Genetics & Immunology Research Group, Department of Diabetes and Cardiovascular Science, UHI Millennium Institute, Inverness IV3 8GY, UK
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198
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Armugam A, Cher CDN, Lim K, Koh DCI, Howells DW, Jeyaseelan K. A secretory phospholipase A2-mediated neuroprotection and anti-apoptosis. BMC Neurosci 2009; 10:120. [PMID: 19775433 PMCID: PMC2758888 DOI: 10.1186/1471-2202-10-120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 09/23/2009] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Phospholipase A2 liberates free fatty acids and lysophospholipids upon hydrolysis of phospholipids and these products are often associated with detrimental effects such as inflammation and cerebral ischemia. The neuroprotective effect of neutral phospholipase from snake venom has been investigated. RESULTS A neutral anticoagulant secretory phospholipase A2 (nPLA) from the venom of Naja sputatrix (Malayan spitting cobra) has been found to reduce infarct volume in rats subjected to focal transient cerebral ischemia and to alleviate the neuronal damage in organotypic hippocampal slices subjected to oxygen-glucose deprivation (OGD). Real-time PCR based gene expression analysis showed that anti-apoptotic and pro-survival genes have been up-regulated in both in vivo and in vitro models. Staurosporine or OGD mediated apoptotic cell death in astrocytoma cells has also been found to be reduced by nPLA with a corresponding reduction in caspase 3 activity. CONCLUSION We have found that a secretory phospholipase (nPLA) purified from snake venom could reduce infarct volume in rodent stroke model. nPLA, has also been found to reduce neuronal cell death, apoptosis and promote cell survival in vitro ischemic conditions. In all conditions, the protective effects could be seen at sub-lethal concentrations of the protein.
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Affiliation(s)
- Arunmozhiarasi Armugam
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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199
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Effects of N-acetylcysteine and ebselen on arachidonic acid release from astrocytes and neurons cultured in normoxic or simulated ischemic conditions. Pharmacol Rep 2009; 61:941-6. [DOI: 10.1016/s1734-1140(09)70153-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 09/25/2009] [Indexed: 11/24/2022]
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200
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Hoda MN, Singh I, Singh AK, Khan M. Reduction of lipoxidative load by secretory phospholipase A2 inhibition protects against neurovascular injury following experimental stroke in rat. J Neuroinflammation 2009; 6:21. [PMID: 19678934 PMCID: PMC2739168 DOI: 10.1186/1742-2094-6-21] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 08/13/2009] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In animal models, ischemia reperfusion (IR) injury triggers membrane lipid degradation and accumulation of lipoxidative exacerbations in neurovascular unit, leading to blood brain barrier (BBB) damage and neurologic deficits. In this study, we investigated whether impeding membrane lipid breakdown by inhibiting secretory phospholipase A2 (sPLA2) activity reduces BBB leakage, leading to neuroprotection and functional recovery. METHODS Focal cerebral IR injury was induced by middle cerebral artery occlusion (MCAO) in adult male rats. A sPLA2 inhibitor, 7,7-dimethyleicosadienoic acid (DEDA), was administered following IR injury. DEDA-treated animals were compared with vehicle-treated in terms of BBB leakage, edema, infarct volume, and neurological deficit. Membrane lipid degradation and the expression/activity of sPLA2 were also assessed. The role of one of the sPLA2 products, arachidonic acid (AA), on the morphology of the differentiated neuronal cell PC12 was examined by light microscopy. RESULTS Treatment with DEDA after IR injury not only reduced BBB leakage but also decreased infarct volume and improved neurologic function. The treatment attenuated both the activity of sPLA2 and the levels of sPLA2-derived oxidized products. The metabolites of lipid oxidation/peroxidation, including the protein carbonyl, were reduced as well. The treatment also restored the levels of glutathione, indicating attenuation of oxidative stress. In vitro treatment of PC12 cells with DEDA did not restore the AA-mediated inhibition of neurite formation and the levels of glutathione, indicating that effect of DEDA is up stream to AA release. CONCLUSION sPLA2-derived oxidative products contribute to significant neurovascular damage, and treatment with sPLA2 inhibitor DEDA ameliorates secondary injury by reducing exacerbations from lipoxidative stress.
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Affiliation(s)
- Md Nasrul Hoda
- Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA.
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