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He YL, Liu DD, Fang YJ, Zhan XQ, Yao JJ, Mei YA. Exposure to extremely low-frequency electromagnetic fields modulates Na+ currents in rat cerebellar granule cells through increase of AA/PGE2 and EP receptor-mediated cAMP/PKA pathway. PLoS One 2013; 8:e54376. [PMID: 23349866 PMCID: PMC3551899 DOI: 10.1371/journal.pone.0054376] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 12/11/2012] [Indexed: 12/19/2022] Open
Abstract
Although the modulation of Ca2+ channel activity by extremely low-frequency electromagnetic fields (ELF-EMF) has been studied previously, few reports have addressed the effects of such fields on the activity of voltage-activated Na+ channels (Nav). Here, we investigated the effects of ELF-EMF on Nav activity in rat cerebellar granule cells (GCs). Our results reveal that exposing cerebellar GCs to ELF-EMF for 10–60 min significantly increased Nav currents (INa) by 30–125% in a time- and intensity-dependent manner. The Nav channel steady-state activation curve, but not the steady-state inactivation curve, was significantly shifted (by 5.2 mV) towards hyperpolarization by ELF-EMF stimulation. This phenomenon is similar to the effect of intracellular application of arachidonic acid (AA) and prostaglandin E2 (PGE2) on INa in cerebellar GCs. Increases in intracellular AA, PGE2 and phosphorylated PKA levels in cerebellar GCs were observed following ELF-EMF exposure. Western blottings indicated that the NaV 1.2 protein on the cerebellar GCs membrane was increased, the total expression levels of NaV 1.2 protein were not affected after exposure to ELF-EMF. Cyclooxygenase inhibitors and PGE2 receptor (EP) antagonists were able to eliminate this ELF-EMF-induced increase in phosphorylated PKA and INa. In addition, ELF-EMF exposure significantly enhanced the activity of PLA2 in cerebellar GCs but did not affect COX-1 or COX-2 activity. Together, these data demonstrate for the first time that neuronal INa is significantly increased by ELF-EMF exposure via a cPLA2 AA PGE2 EP receptors PKA signaling pathway.
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Affiliation(s)
- Yan-Lin He
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Dong-Dong Liu
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan-Jia Fang
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiao-Qin Zhan
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Jin-Jing Yao
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan-Ai Mei
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
- * E-mail:
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Narayanankutty A, Reséndiz-Hernández JM, Falfán-Valencia R, Teran LM. Biochemical pathogenesis of aspirin exacerbated respiratory disease (AERD). Clin Biochem 2012; 46:566-78. [PMID: 23246457 DOI: 10.1016/j.clinbiochem.2012.12.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 11/14/2012] [Accepted: 12/04/2012] [Indexed: 12/30/2022]
Abstract
Aspirin exacerbated respiratory disease (AERD) is a distinct clinical entity characterized by eosinophilic rhinosinusitis, asthma and often nasal polyposis. Exposure to aspirin or other nonsteroid anti-inflammatory drugs (NSAIDs) exacerbates bronchospasms with asthma and rhinitis. Disease progression suggests a skewing towards TH2 type cellular response along with moderate to severe eosinophil and mast cell infiltration. Alterations in upper and lower airway cellular milieu with abnormalities in eicosanoid metabolism and altered eicosanoid receptor expression are the key features underlying AERD pathogenesis. Dysregulation of arachidonic acid (AA) metabolism, notably reduced prostaglandin E2 (PGE2) synthesis compared to their aspirin tolerant counterpart and relatively increased PGD2 production, a TH2/eosinophil chemoattractant are reported in AERD. Underproduced PGE2 is metabolized by overexpression of 15 prostaglandin dehydrogenase (15-PGDH) to inactive products further reducing PGE2 at real time. This relives the inhibitory effect of PGE2 on 5-lipoxygenase (5-LOX) resulting in overproduction of cysteinyl leukotrienes (CysLTs). Diminished formation of CysLT antagonists called lipoxins (LXs) also augments CysLTs responsiveness. Occasional intake of NSAIDs favors even more 5-LOX product formation, further narrowing the bronchoconstrictive bottle neck, resulting in acute asthmatic exacerbations along with increased mucus production. This review focuses on abnormalities in biochemical and molecular mechanisms in eicosanoid biosynthesis, eicosanoid receptor dysregulation and associated polymorphisms with special reference to arachidonic acid metabolism in AERD.
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Affiliation(s)
- Arun Narayanankutty
- Department of Immunoallergy and Asthma, Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas, Calzada de Tlalpan 4502, Col. Sección XVI, Delegación Tlalpan, C.P. 14080, Mexico.
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C2-di-ethyl-ceramide-1-phosphate as an inhibitor of group IVA cytosolic phospholipase A2. Eur J Pharmacol 2012; 697:144-51. [DOI: 10.1016/j.ejphar.2012.09.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 09/19/2012] [Accepted: 09/22/2012] [Indexed: 11/18/2022]
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104
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Davignon JL, Hayder M, Baron M, Boyer JF, Constantin A, Apparailly F, Poupot R, Cantagrel A. Targeting monocytes/macrophages in the treatment of rheumatoid arthritis. Rheumatology (Oxford) 2012. [PMID: 23204551 DOI: 10.1093/rheumatology/kes304] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Biotherapies have revolutionized the treatment of RA. However, much work is needed to understand all the mechanisms of these biotherapies, and alternatives are needed to circumvent adverse effects and the high cost of these long-lasting treatments. In this article we outline some of the approaches we have used to target monocytes/macrophages as major components of inflammation and bone homeostasis. We also discuss how anti-TNF-α antibodies target monocytes/macrophages in the complex mechanisms contributing to inhibition of inflammation.
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105
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Impaired thrombin-induced platelet activation and thrombus formation in mice lacking the Ca(2+)-dependent tyrosine kinase Pyk2. Blood 2012; 121:648-57. [PMID: 23175689 DOI: 10.1182/blood-2012-06-438762] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, we used a knockout murine model to analyze the contribution of the Ca(2+)-dependent focal adhesion kinase Pyk2 in platelet activation and thrombus formation in vivo. We found that Pyk2-knockout mice had a tail bleeding time that was slightly increased compared with their wild-type littermates. Moreover, in an in vivo model of femoral artery thrombosis, the time to arterial occlusion was significantly prolonged in mice lacking Pyk2. Pyk2-deficient mice were also significantly protected from collagen plus epinephrine-induced pulmonary thromboembolism. Ex vivo aggregation of Pyk2-deficient platelets was normal on stimulation of glycoprotein VI, but was significantly reduced in response to PAR4-activating peptide, low doses of thrombin, or U46619. Defective platelet aggregation was accompanied by impaired inside-out activation of integrin α(IIb)β(3) and fibrinogen binding. Granule secretion was only slightly reduced in the absence of Pyk2, whereas a marked inhibition of thrombin-induced thromboxane A(2) production was observed, which was found to be responsible for the defective aggregation. Moreover, we have demonstrated that Pyk2 is implicated in the signaling pathway for cPLA(2) phosphorylation through p38 MAPK. The results of the present study show the importance of the focal adhesion kinase Pyk2 downstream of G-protein-coupled receptors in supporting platelet aggregation and thrombus formation.
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106
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Iacono F, Prezioso D, Illiano E, Ruffo A, Romeo G, Amato B. Observational study: daily treatment with a new compound "Tradamixina" plus serenoa repens for two months improved the lower urinary tract symptoms. BMC Surg 2012; 12 Suppl 1:S22. [PMID: 23173650 PMCID: PMC3499205 DOI: 10.1186/1471-2482-12-s1-s22] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lower urinary tract symptoms (LUTS) are associated with great emotional costs to individuals and substantial economic costs to society. This study seeks to evaluate the effect of a new natural compound "Tradamixina plus Serenoa Repens" in order to improve lower urinary tract symptoms. METHODS 100 patients (≥ 45 years) who had had LUTS/BPH for >6 mo at screening and with IPSS -The international Prostate symptom scores- ≥ 13 and maximum urinary flow rate (Qmax) ≥ 4 to ≤ 15 ml/s. were recruited. The compound "Tradamixina plus Serenoa Repens" (80 mg of Alga Ecklonia Bicyclis, 100 mg of Tribulus Terrestris and 100 mg of D-Glucosamine and N-Acetyl-D-Glucosamine plus 320 mg of Serenoa Repens) was administered daily for 2 months. At visit and after 60 days of treatment patients were evaluated by means of detailed medical urological history, clinical examination, laboratory investigations (total PSA), and instrumental examination like urolfowmetry. Efficacy measures included IPSS-International Prostate Sympto, BPH Impact Index (BII), Quality-of-Life (QoL) Index. Measures were assessed at baseline and end point (12 wk or end of therapy) and also at screening, 1 and 4 wk for IPSS, and 4 wk for BII. Statistical significance was interpreted only if the results of the preceding analysis were significant at the 0.05 level. RESULTS After 2 months of treatment the change from baseline to week 12 relative to "Tradamixina plus Seronea Repens" in total IPSS and Qol was statistically significant. Differences from baseline in BII were statistically significant for "Tradamixina plus Seronea Repens" above all differences in BII were also significant at 4 wk (LSmean ± SE: -0.8 ± 0.2). In the distribution of subjects over the PGI-I and CGI-I response categories were significant for"Tradamixina plus Seronea Repens" (PGI-I: p = 0.001; CGI-I). We also observed a decrease of total PSA. CONCLUSION The daily treatment with a new compound "Tradamixina plus Serenoa Repens" for 2 months improved the male sexual function , it improved the bother symptoms which affect the patient's quality of life , improved uroflowmetric parameters, and we also observed a decrease of serum PSA level.
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Affiliation(s)
- Fabrizio Iacono
- Department of Urology – University Federico II of Naples, Via S. Pansini, 5 – 80131 Naples – Italy
| | - Domenico Prezioso
- Department of Urology – University Federico II of Naples, Via S. Pansini, 5 – 80131 Naples – Italy
| | - Ester Illiano
- Department of Urology – University Federico II of Naples, Via S. Pansini, 5 – 80131 Naples – Italy
| | - Antonio Ruffo
- Department of Urology – University Federico II of Naples, Via S. Pansini, 5 – 80131 Naples – Italy
| | - Giuseppe Romeo
- Department of Urology – University Federico II of Naples, Via S. Pansini, 5 – 80131 Naples – Italy
| | - Bruno Amato
- Department of General, Geriatric, Oncologic Surgery and Advanced Technologies,-University “Federico II” of Naples. Via Pansini, 5 - 80131 – Naples, Italy
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Szymanski PT, Muley P, Ahmed SA, Khalifa S, Fahmy H. Sarcophine-diol inhibits expression of COX-2, inhibits activity of cPLA2, enhances degradation of PLA2 and PLC(γ)1 and inhibits cell membrane permeability in mouse melanoma B16F10 cells. Mar Drugs 2012; 10:2166-2180. [PMID: 23170076 PMCID: PMC3497015 DOI: 10.3390/md10102166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/20/2012] [Accepted: 09/21/2012] [Indexed: 12/28/2022] Open
Abstract
Sarcophine-diol (SD) is a semi-synthetic derivative of sarcophine with a significant chemopreventive effect against non-melanoma skin cancer both in vitro and in vivo. Recently, we have studied the effect of SD on melanoma development using the mouse melanoma B₁₆F₁₀ cell line. In this study, our findings show that SD suppresses cell multiplication and diminishes membrane permeability for ethidium bromide (EB), a model marker used to measure cell permeability for Ca²⁺ ions. SD also decreases protein levels of COX-2, and increases degradation of phospholipases PLA₂ and PLC(γ)1 and diminishes enzymatic activity of the Ca²⁺-dependent cPLA₂. This lower membrane permeability for Ca²⁺-ions, associated with SD, is most likely due to the diminished content of lysophosphosphatidylcholine (lysoPC) within cell membranes caused by the effect of SD on PLA₂. The decrease in diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP₃) due to inhibition of PLC(γ)1, leads to the downregulation of Ca²⁺-dependent processes within the cell and also inhibits the formation of tumors. These findings support our previous data suggesting that SD may have significant potential in the treatment of melanoma.
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Affiliation(s)
- Pawel T. Szymanski
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
| | - Pratik Muley
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
| | - Safwat A. Ahmed
- Department of Pharmacognosy, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt;
| | | | - Hesham Fahmy
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
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108
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Rodríguez Diez G, Uranga RM, Mateos MV, Giusto NM, Salvador GA. Differential participation of phospholipase A2 isoforms during iron-induced retinal toxicity. Implications for age-related macular degeneration. Neurochem Int 2012; 61:749-58. [PMID: 22732705 DOI: 10.1016/j.neuint.2012.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 06/06/2012] [Accepted: 06/14/2012] [Indexed: 01/01/2023]
Abstract
Both elevated iron concentrations and the resulting oxidative stress condition are common signs in retinas of patients with age-related macular degeneration (AMD). The role of phospholipase A(2) (PLA(2)) during iron-induced retinal toxicity was investigated. To this end, isolated retinas were exposed to increasing Fe(2+) concentrations (25, 200 or 800 μM) or to the vehicle, and lipid peroxidation levels, mitochondrial function, and the activities of cytosolic PLA(2) (cPLA(2)) and calcium-independent PLA(2) (iPLA(2)) were studied. Incubation with Fe(2+) led to a time- and concentration-dependent increase in retinal lipid peroxidation levels whereas retinal cell viability was only affected after 60 min of oxidative injury. A differential release of arachidonic acid (AA) and palmitic acid (PAL) catalyzed by cPLA(2) and iPLA(2) activities, respectively, was also observed in microsomal and cytosolic fractions obtained from retinas incubated with iron. AA release diminished as the association of cyclooxygenase-2 increased in microsomes from retinas exposed to iron. Retinal lipid peroxidation and cell viability were also analyzed in the presence of cPLA(2) inhibitor, arachidonoyl trifluoromethyl ketone (ATK), and in the presence of iPLA(2) inhibitor, bromoenol lactone (BEL). ATK decreased lipid peroxidation levels and also ERK1/2 activation without affecting cell viability. BEL showed the opposite effect on lipid peroxidation. Our results demonstrate that iPLA(2) and cPLA(2) are differentially regulated and that they selectively participate in retinal signaling in an experimental model resembling AMD.
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Affiliation(s)
- G Rodríguez Diez
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, 8000 Bahía Blanca, Argentina
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109
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Maintenance of synaptic stability requires calcium-independent phospholipase A₂ activity. Neural Plast 2012; 2012:569149. [PMID: 22685677 PMCID: PMC3364014 DOI: 10.1155/2012/569149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/03/2012] [Accepted: 02/07/2012] [Indexed: 12/31/2022] Open
Abstract
Phospholipases A₂ (PLA₂s) represent one of the largest groups of lipid-modifying enzymes. Over the years, significant advances have been made in understanding their potential physiological and pathological functions. Depending on their calcium requirement for activation, PLA₂s are classified into calcium dependent and independent. This paper mainly focuses on brain calcium-independent PLA₂ (iPLA₂) and on the mechanisms by which they influence neuronal function and regulate synaptic plasticity. Particular attention will be given to the iPLA₂γ isoform and its role in the regulation of synaptic glutamate receptors. In particular, the paper discusses the possibility that brain iPLA₂γ deficiencies could destabilise normal synaptic operation and might contribute to the aetiology of some brain disorders. In this line, the paper presents new data indicating that iPLA₂γ deficiencies accentuate AMPA receptor destabilization and tau phosphorylation, which suggests that this iPLA₂ isoform should be considered as a potential target for the treatment of Tau-related disorders.
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110
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Saber R, Zadeh M, Pakanati KC, Bere P, Klaenhammer T, Mohamadzadeh M. Lipoteichoic acid-deficient Lactobacillus acidophilus regulates downstream signals. Immunotherapy 2012; 3:337-47. [PMID: 21395377 DOI: 10.2217/imt.10.119] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The trillions of microbes residing within the intestine induce critical signals that either regulate or stimulate host immunity via their bacterial products. To better understand the immune regulation elicited by lipoteichoic acid (LTA)-deficient Lactobacillus acidophilus NCFM in steady state and induced inflammation, we deleted phosphoglycerol transferase gene, which synthesizes LTA in L. acidophilus NCFM. In vitro and in vivo experiments were conducted in order to compare the immune regulatory properties of the L. acidophilus strain deficient in LTA (NCK2025) with its wild-type parent (NCK56) in C57BL/6, C57BL/6 recombination-activation gene 1-deficient (Rag1 (-/-)) and C57BL/6 Rag1(-/-)IL-10(-/-) mice. We demonstrate that NCK2025 significantly activates the phosphorylation of Erk1/2 but downregulates the phosphorylation of Akt1, cytosolic group IV PLA2 and p38 in mouse dendritic cells. Similarly, mice treated orally with NCK2025 exhibit decreased phosphorylation of inflammatory signals (Akt1, cytosolic group IV PLA2 or P38) but upregulate Erk1/2-phosphorylation in colonic epithelial cells in comparison with mice treated with NCK56. In addition, regulation of pathogenic CD4+ T cell induced colitis by NCK2025 was observed in Rag1 (-/-) but not Rag1(-/-)IL-10 (-/-) mice suggests a critical role of IL-10 that may be tightly regulated by Erk1/2 signaling. These data highlight the immunosuppressive properties of NCK2025 to deliver regulatory signals in innate cells, which results in the mitigation of T-cell-induced colitis in vivo.
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Affiliation(s)
- Rana Saber
- Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
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Choi J, Kim SH, Kim S. Suppressive effects of PG201, an antiarthritic botanical formulation, on lipopolysaccharide-induced inflammatory mediators in Raw264.7 cells. Exp Biol Med (Maywood) 2012; 237:499-508. [PMID: 22442340 DOI: 10.1258/ebm.2011.011203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PG201, an ethanol extract from a mixture of 12 herbs, has strong antiarthritic activity. To understand the molecular mechanisms underlying its anti-inflammatory effects, PG201-mediated suppression of inflammatory mediators was studied in Raw264.7, a mouse macrophage cell line. PG201 decreased the expression of interleukin (IL)-1β, IL-6 and CC chemokine ligand-2, but not tumor necrosis factor-α, at the protein and mRNA levels in lipopolysaccharide-stimulated Raw264.7 cells. Results from a gel retardation assay indicated that PG201 substantially reduced the DNA-binding activity of the activator protein-1 and cyclic adenosine monophosphate-responsive element-binding protein transcription factors, but not nuclear factor-κB. Western blot and Northern blot analyses showed that PG201 reduced inducible nitric oxide synthase and cytosolic phospholipase A(2) (cPLA(2)) protein expression, but did not affect mRNA expression, ultimately resulting in decreased nitric oxide and prostaglandin E(2). The protein expression of cPLA(2) was decreased by PG201 in the presence of cycloheximide, an inhibitor of translation, suggesting that PG201 may facilitate the degradation of cPLA(2). Taken together, these results suggest that PG201 selectively affects the expression of proteins that play key roles in the inflammatory response at transcriptional and post-translational levels.
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Affiliation(s)
- Jinyong Choi
- School of Biological Sciences, Seoul National University, Seoul 151-742, Korea
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112
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Saito Y, Watanabe K, Fujioka D, Nakamura T, Obata JE, Kawabata K, Watanabe Y, Mishina H, Tamaru S, Kita Y, Shimizu T, Kugiyama K. Disruption of group IVA cytosolic phospholipase A(2) attenuates myocardial ischemia-reperfusion injury partly through inhibition of TNF-α-mediated pathway. Am J Physiol Heart Circ Physiol 2012; 302:H2018-30. [PMID: 22427514 DOI: 10.1152/ajpheart.00955.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Group IVA cytosolic phospholipase A(2) (cPLA(2)α), which preferentially cleaves arachidonic acid from phospholipids, plays a role in apoptosis and tissue injury. Downstream signals in response to tumor necrosis factor (TNF)-α, a mediator of myocardial ischemia-reperfusion (I/R) injury, involve cPLA(2)α activation. This study examined the potential role of cPLA(2)α and its mechanistic link with TNF-α in myocardial I/R injury using cPLA(2)α knockout (cPLA(2)α(-/-)) mice. Myocardial I/R was created with 10-wk-old male mice by 1 h ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. As a result, compared with wild-type (cPLA(2)α(+/+)) mice, cPLA(2)α(-/-) mice had a 47% decrease in myocardial infarct size, preservation of echocardiographic left ventricle (LV) function (%fractional shortening: 14 vs. 21%, respectively), and lower content of leukotriene B(4) and thromboxane B(2) (62 and 50% lower, respectively) in the ischemic myocardium after I/R. Treatment with the TNF-α inhibitor (soluble TNF receptor II/IgG1 Fc fusion protein, sTNFR:Fc) decreased myocardial I/R injury and LV dysfunction in cPLA(2)α(+/+) mice but not cPLA(2)α(-/-) mice. sTNFR:Fc also suppressed cPLA(2)α phosphorylation in the ischemic myocardium after I/R of cPLA(2)α(+/+) mice. Similarly, sTNFR:Fc exerted protective effects against hypoxia-reoxygenation (H/R)-induced injury in the cultured cardiomyocytes from cPLA(2)α(+/+) mice but not cPLA(2)α(-/-) cardiomyocytes. H/R and TNF-α induced cPLA(2)α phosphorylation in cPLA(2)α(+/+) cardiomyocytes, which was reversible by sTNFR:Fc. In cPLA(2)α(-/-) cardiomyocytes, TNF-α induced apoptosis and release of arachidonic acid to a lesser extent than in cPLA(2)α(+/+) cardiomyocytes. In conclusion, disruption of cPLA(2)α attenuates myocardial I/R injury partly through inhibition of TNF-α-mediated pathways.
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Affiliation(s)
- Yukio Saito
- Department of Internal Medicine II, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
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Zizza P, Iurisci C, Bonazzi M, Cossart P, Leslie CC, Corda D, Mariggiò S. Phospholipase A2IVα regulates phagocytosis independent of its enzymatic activity. J Biol Chem 2012; 287:16849-59. [PMID: 22393044 DOI: 10.1074/jbc.m111.309419] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Group IVα phospholipase A(2) (PLA(2)IVα) is a lipolytic enzyme that catalyzes the hydrolysis of membrane phospholipids to generate precursors of potent inflammatory lipid mediators. Here, the role of PLA(2)IVα in Fc receptor (FcR)-mediated phagocytosis was investigated, demonstrating that PLA(2)IVα is selectively activated upon FcR-mediated phagocytosis in macrophages and that it rapidly translocates to the site of the nascent phagosome. Moreover, pharmacological inhibition of PLA(2)IVα by pyrrophenone reduces particle internalization by up to 50%. In parallel, fibroblasts from PLA(2)IVα knock-out mice overexpressing FcγRIIA and able to internalize IgG-opsonized beads show 50% lower phagocytosis, compared with wild-type cells, and transfection of PLA(2)IVα fully recovers this impaired function. Interestingly, transfection of the catalytically inactive deleted PLA(2)IVα mutant (PLA(2)IVα(1-525)) and point mutant (PLA(2)IVα-S228C) also promotes recovery of this impaired function. Finally, transfection of the PLA(2)IVα C2 domain (which is directly involved in PLA(2)IVα membrane binding), but not of PLA(2)IVα-D43N (which cannot bind to membranes), rescues FcR-mediated phagocytosis. These data unveil a new mechanism of action for PLA(2)IVα, which demonstrates that the membrane binding, and not the enzymatic activity, is required for PLA(2)IVα modulation of FcR-mediated phagocytosis.
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Affiliation(s)
- Pasquale Zizza
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
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114
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Gutowska I, Baranowska-Bosiacka I, Siennicka A, Telesiński A, Stańczyk-Dunaj M, Wesołowska T, Gąssowska M, Kłos P, Zakrzewska H, Machaliński B, Chlubek D, Stachowska E. Activation of phospholipase A(2) by low levels of fluoride in THP1 macrophages via altered Ca(2+) and cAMP concentration. Prostaglandins Leukot Essent Fatty Acids 2012; 86:99-105. [PMID: 22382002 DOI: 10.1016/j.plefa.2012.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 02/04/2012] [Accepted: 02/06/2012] [Indexed: 10/28/2022]
Abstract
Phospholipases (PLA's) participate in the regulation of physiological and pathological processes in the cell, including the release of pro-inflammatory mediators and stimulation of inflammatory processes. It is also well known that fluoride can increase the inflammatory reactions. Therefore we decided to examine the effect of fluorides in concentrations determined in human serum on cPLA(2) and sPLA(2) activity. The incubation of macrophages in fluoride solutions significantly increased the amount of synthesized cellular cAMP, intracellular calcium and sPLA(2) activity in a dose-dependent pattern. The cPLA(2) activity, estimated by the amount of released arachidonic acid, increased significantly when 10 μM NaF was used. The results of our study suggest that fluoride may change the activity of phospholipases in macrophage cells. Probably, increased cAMP concentration activates protein kinase C (PKC) and thus stimulates PLA(2). cAMP also regulates the passage of Ca(2+) through ion channels, which additionally influence PLA(2) throughout Ca(2+)-calmodulin dependent protein kinase.
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Affiliation(s)
- I Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, ul. Żołnierska 48, Szczecin, Poland.
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Shoeb M, Ramana KV. Anti-inflammatory effects of benfotiamine are mediated through the regulation of the arachidonic acid pathway in macrophages. Free Radic Biol Med 2012; 52:182-90. [PMID: 22067901 PMCID: PMC3249497 DOI: 10.1016/j.freeradbiomed.2011.10.444] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/11/2011] [Accepted: 10/16/2011] [Indexed: 11/23/2022]
Abstract
Benfotiamine, a lipid-soluble analogue of vitamin B1, is a potent antioxidant that is used as a food supplement for the treatment of diabetic complications. Our recent study (U.C. Yadav et al., Free Radic. Biol. Med. 48:1423-1434, 2010) indicates a novel role for benfotiamine in the prevention of bacterial endotoxin, lipopolysaccharide (LPS)-induced cytotoxicity and inflammatory response in murine macrophages. Nevertheless, it remains unclear how benfotiamine mediates anti-inflammatory effects. In this study, we investigated the anti-inflammatory role of benfotiamine in regulating arachidonic acid (AA) pathway-generated inflammatory lipid mediators in RAW264.7 macrophages. Benfotiamine prevented the LPS-induced activation of cPLA2 and release of AA metabolites such as leukotrienes, prostaglandin E2, thromboxane 2 (TXB2), and prostacyclin (PGI2) in macrophages. Further, LPS-induced expression of AA-metabolizing enzymes such as COX-2, LOX-5, TXB synthase, and PGI2 synthase was significantly blocked by benfotiamine. Furthermore, benfotiamine prevented the LPS-induced phosphorylation of ERK1/2 and expression of transcription factors NF-κB and Egr-1. Benfotiamine also prevented the LPS-induced oxidative stress and protein-HNE adduct formation. Most importantly, compared to specific COX-2 and LOX-5 inhibitors, benfotiamine significantly prevented LPS-induced macrophage death and monocyte adhesion to endothelial cells. Thus, our studies indicate that the dual regulation of the COX and LOX pathways in AA metabolism could be a novel mechanism by which benfotiamine exhibits its potential anti-inflammatory response.
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Affiliation(s)
| | - Kota V Ramana
- Correspondence: Kota V Ramana, PhD, , Telephone (409)-772-2202, Fax: 409-772-9679 and mailing address: #6.614D BSB, Department of Biochemistry and Molecular biology, University of Texas Medical Branch, Galveston, Texas -77555, USA
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116
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Kerkelä R, Boucher M, Zaka R, Gao E, Harris D, Piuhola J, Song J, Serpi R, Woulfe KC, Cheung JY, O'Leary E, Bonventre JV, Force T. Cytosolic phospholipase A(2)α protects against ischemia/reperfusion injury in the heart. Clin Transl Sci 2011; 4:236-42. [PMID: 21884509 DOI: 10.1111/j.1752-8062.2011.00294.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Studies with sPLA(2) Group X, and cPLA(2) α gene-targeted mice suggest that absence of sPLA(2) Group X results in protection from ischemia/reperfusion (I/R) injury in the heart, and absence of cPLA(2) α Group IV is protective in the brain. Although latter studies might suggest a similar deleterious role for cPLA(2) α in I/R injury in the heart, the pathophysiology of stroke is intricately related to excitotoxicity and cannot necessarily be extrapolated to the heart. We report here that unlike findings in the brain, cPLA(2) α((-/-)) mice have exaggerated injury following I/R in vivo. In contrast, there is no difference in injury induced by simulated ischemia in cardiomyocytes isolated from cPLA(2) α((-/-)) versus cPLA(2) α((+/+)) mice. This suggests that cPLA(2) α does not have an important cardiomyocyte autonomous effect on ischemic injury. Prostaglandin E(2) (PGE(2) ) levels are significantly reduced in the hearts of the cPLA(2) α((-/-)) mice, and the enhanced injury is ameliorated by treatment with the PGE analog, misoprostol. We demonstrate that cPLA(2) α is cardioprotective in vivo, and this is likely via cPLA(2) α-mediated production of cardioprotective eicosanoids. These studies are the first to identify a protective role for cPLA(2) in I/R injury in any organ and raise concerns over long-term inhibition of cPLA(2).
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Affiliation(s)
- Risto Kerkelä
- Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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117
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Ishihara K, Kuroda A, Sugihara K, Kanai S, Nabe T, Akiba S. Regulation of macrophage differentiation and polarization by group IVC phospholipase A2. Biochem Biophys Res Commun 2011; 416:325-30. [DOI: 10.1016/j.bbrc.2011.11.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/05/2011] [Indexed: 01/19/2023]
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118
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Shoeb M, Yadav UCS, Srivastava SK, Ramana KV. Inhibition of aldose reductase prevents endotoxin-induced inflammation by regulating the arachidonic acid pathway in murine macrophages. Free Radic Biol Med 2011; 51:1686-96. [PMID: 21856412 PMCID: PMC3188329 DOI: 10.1016/j.freeradbiomed.2011.07.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/27/2011] [Accepted: 07/28/2011] [Indexed: 12/27/2022]
Abstract
The bacterial endotoxin lipopolysaccharide (LPS) is known to induce release of arachidonic acid (AA) and its metabolic products, which play important roles in the inflammatory process. We have shown earlier that LPS-induced signals in macrophages are mediated by aldose reductase (AR). Here we have investigated the role of AR in LPS-induced release of AA metabolites and their modulation using a potent pharmacological inhibitor, fidarestat, and AR siRNA ablation in RAW264.7 macrophages and AR-knockout mouse peritoneal macrophages and heart tissue. Inhibition or genetic ablation of AR prevented the LPS-induced synthesis and release of AA metabolites such as PGE2, TXB, PGI2, and LTBs in macrophages. LPS-induced activation of cPLA2 was also prevented by AR inhibition. Similarly, AR inhibition also prevented the calcium ionophore A23187-induced cPLA2 and LTB4 in macrophages. Further, AR inhibition by fidarestat prevented the expression of AA-metabolizing enzymes such as COX-2 and LOX-5 in RAW264.7 cells and AR-knockout mouse-derived peritoneal macrophages. LPS-induced expression of AA-metabolizing enzymes and their catalyzed metabolic products was significantly lower in peritoneal macrophages and heart tissue from AR-knockout mice. LPS-induced activation of redox-sensitive signaling intermediates such as MAPKs, transcription factor NF-κB, and EGR-1, a transcriptional regulator of mPGES-1, which in collaboration with COX-2 leads to the production of PGE2, was also significantly prevented by AR inhibition. Taken together, our results indicate that AR mediates LPS-induced inflammation by regulating the AA-metabolic pathway and thus provide a novel role for AR inhibition in preventing inflammatory complications such as sepsis.
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Affiliation(s)
| | | | | | - Kota V Ramana
- Correspondence: Kota V Ramana, PhD , Telephone (409)-772-2202, Fax: 409-772-9679 and mailing address: #6.614D BSB, Department of Biochemistry and Molecular biology, University of Texas Medical Branch, Galveston, Texas -77555, USA
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119
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Takahashi N, Kozai D, Kobayashi R, Ebert M, Mori Y. Roles of TRPM2 in oxidative stress. Cell Calcium 2011; 50:279-87. [DOI: 10.1016/j.ceca.2011.04.006] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/19/2011] [Accepted: 04/22/2011] [Indexed: 12/15/2022]
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120
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121
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Lee CW, Lin CC, Lee IT, Lee HC, Yang CM. Activation and induction of cytosolic phospholipase A2 by TNF-α mediated through Nox2, MAPKs, NF-κB, and p300 in human tracheal smooth muscle cells. J Cell Physiol 2011; 226:2103-14. [PMID: 21520062 DOI: 10.1002/jcp.22537] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cytosolic phospholipase A(2) (cPLA(2)) plays a pivotal role in mediating agonist-induced arachidonic acid (AA) release for prostaglandin (PG) synthesis during inflammation triggered by tumor necrosis factor-α (TNF-α). However, the mechanisms underlying TNF-α-induced cPLA(2) expression and PGE(2) synthesis in human tracheal smooth muscle cells (HTSMCs) remain unknown. Here, we report that TNF-α-induced cPLA(2) protein and mRNA expression, PGE(2) production, and phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK1/2, which were attenuated by pretreatment with a ROS scavenger [N-acetyl-L-cysteine, (NAC)] and the inhibitors of NADPH oxidase [apocynin (APO) and diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), and JNK1/2 (SP600125) or transfection with siRNA of Nox2, p47(phox) , MEK1, p42, p38, or JNK2. TNF-α-induced cPLA(2) expression was also inhibited by pretreatment with a selective NF-κB inhibitor [helenalin (HLN)] or transfection with dominant negative mutants of NF-κB inducing kinase (NIK) or IκB kinase (IKK)α/β. TNF-α-induced NF-κB translocation was blocked by pretreatment with NAC, DPI, APO, or HLN, but not by U0126, SB202190, or SP600125. In addition, pretreatment with curcumin (a p300 inhibitor) or transfection with p300 siRNA blocked cPLA(2) expression and PGE(2) synthesis induced by TNF-α. We further confirmed that p300 was associated with the cPLA(2) promoter which was dynamically linked to histone H4 acetylation stimulated by TNF-α, determined by chromatin immunoprecipitation assay. Association of p300 and histone H4 to cPLA(2) promoter was inhibited by U0126, SB202190, and SP600125. These results suggested that in HTSMCs, activation of p47(phox) , MAPKs, NF-κB, and p300 is essential for TNF-α-induced cPLA(2) expression and PGE(2) release.
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Affiliation(s)
- Chiang-Wen Lee
- Department of Nursing, Division of Basic Medical Sciences, Chronic Diseases and Health Promotion Research Center, Chang Gung Institute of Technology, Chia-Yi, Taiwan
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122
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Di R, Huang MT, Ho CT. Anti-inflammatory activities of mogrosides from Momordica grosvenori in murine macrophages and a murine ear edema model. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:7474-7481. [PMID: 21631112 DOI: 10.1021/jf201207m] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Momordica grosvenori (Luo Han Guo), grown primarily in Guangxi province in China, has been traditionally used for thousands of years by the Chinese to make hot drinks for the treatment of sore throat and the removal of phlegm. The natural noncaloric sweetening triterpenoid glycosides (mogrosides) contained in the M. grosvenori fruits are also antioxidative, anticarcinogenic, and helpful in preventing diabetic complications. The aim of this study was to assess the anti-inflammatory properties of mogrosides in both murine macrophage RAW 264.7 cells and a murine ear edema model. The results indicate that mogrosides can inhibit inflammation induced by lipopolysaccharides (LPS) in RAW 264.7 cells by down-regulating the expression of key inflammatory genes iNOS, COX-2, and IL-6 and up-regulating some inflammation protective genes such as PARP1, BCL2l1, TRP53, and MAPK9. Similarly, in the murine ear edema model, 12-O-tetradecanoylphorbol-13-acetate-induced inflammation was inhibited by mogrosides by down-regulating COX-2 and IL-6 and up-regulating PARP1, BCL2l1, TRP53, MAPK9, and PPARδ gene expression. This study shows that the anticancer and antidiabetic effects of M. grosvenori may result in part from its anti-inflammatory activity.
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Affiliation(s)
- Rong Di
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, USA.
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123
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Hui E, Gaffaney JD, Wang Z, Johnson CP, Evans CS, Chapman ER. Mechanism and function of synaptotagmin-mediated membrane apposition. Nat Struct Mol Biol 2011; 18:813-21. [PMID: 21642967 PMCID: PMC3130839 DOI: 10.1038/nsmb.2075] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 04/28/2011] [Indexed: 11/09/2022]
Abstract
Synaptotagmin-I (syt) is a Ca2+ sensor that triggers synchronous neurotransmitter release. The first documented biochemical property of syt was its ability to aggregate membranes in response to Ca2+. However, the mechanism and function of syt-mediated membrane aggregation are poorly understood. Here, we demonstrate that syt-mediated vesicle aggregation is driven by trans interactions between syt molecules bound to different membranes. We observed a strong correlation between the ability of Ca2+-syt to aggregate vesicles and to stimulate SNARE-mediated membrane fusion. Moreover, artificial aggregation of membranes - using non-syt proteins - also efficiently promoted fusion of SNARE-bearing liposomes. Finally, using a modified fusion assay, we observed that syt drives the assembly of otherwise non-fusogenic individual t-SNARE proteins into fusion competent heterodimers, in an aggregation-independent manner. Thus, membrane aggregation and t-SNARE assembly appear to be two key aspects of Ca2+-syt-regulated, SNARE-catalyzed fusion reactions.
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Affiliation(s)
- Enfu Hui
- Howard Hughes Medical Institute and Department of Neuroscience, University of Wisconsin, Madison, Wisconsin, USA
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124
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Yoo YS, Lim SC, Kim KJ. Prognostic significance of cytosolic phospholipase A2 expression in patients with colorectal cancer. JOURNAL OF THE KOREAN SURGICAL SOCIETY 2011; 80:397-403. [PMID: 22066066 PMCID: PMC3204686 DOI: 10.4174/jkss.2011.80.6.397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 03/09/2011] [Indexed: 02/07/2023]
Abstract
PURPOSE Cyclooxygenase-2 is believed to be an important enzyme in the pathogenesis of colorectal cancer (CRC). Cytosolic phospholipase A2 (cPLA2), also, have been suggested to be related to the carcinogenesis of CRC. The aim of this study was to investigate cPLA2 expression and its relationship with prognostic significance in CRC. METHODS Eighty-eight patients with colorectal cancer who underwent curative surgery were enrolled in this study. cPLA2 was examined in 88 primary CRCs by immunohistochemistry and we compared their expression with clinicopathologic findings, recurrence and survival in patients with CRC. RESULTS The expression of cPLA2 was positive in 54.5% (48/88). The expression of cPLA2 was not correlated with clinicopathologic parameters. However, cPLA2 expression was significantly related with vascular endothelial growth factor expression. Kaplan-Meier analysis didn't show any clinical significance in disease-free survival and overall survival according to cPLA2 expression. CONCLUSION These results suggest that cPLA2 expression was not associated with the prognosis of CRC. However, further large-scale studies are needed to clarify the prognostic effect of cPLA2 in CRC.
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Affiliation(s)
- Young Sun Yoo
- Department of Surgery, Chosun University College of Medicine, Gwangju, Korea
| | - Sung Chul Lim
- Department of Pathology, Chosun University College of Medicine, Gwangju, Korea
| | - Kyung Jong Kim
- Department of Surgery, Chosun University College of Medicine, Gwangju, Korea
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125
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Zhang Q, Wang D, Singh NK, Kundumani-Sridharan V, Gadiparthi L, Rao CM, Rao GN. Activation of cytosolic phospholipase A2 downstream of the Src-phospholipase D1 (PLD1)-protein kinase C γ (PKCγ) signaling axis is required for hypoxia-induced pathological retinal angiogenesis. J Biol Chem 2011; 286:22489-98. [PMID: 21536681 DOI: 10.1074/jbc.m110.217786] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In view of understanding the mechanisms of retinal neovascularization, we had reported previously that vascular endothelial growth factor (VEGF)-induced pathological retinal angiogenesis requires the activation of Src-PLD1-PKCγ signaling. In the present work, we have identified cytosolic phospholipase A(2) (cPLA(2)) as an effector molecule of Src-PLD1-PKCγ signaling in the mediation of VEGF-induced pathological retinal angiogenesis based on the following observations. VEGF induced cPLA(2) phosphorylation in a time-dependent manner in human retinal microvascular endothelial cells (HRMVECs). VEGF also induced arachidonic acid (AA) release in a dose-, time-, and cPLA(2)-dependent manner. Depletion of cPLA(2) levels inhibited VEGF-induced HRMVEC DNA synthesis, migration, and tube formation. In addition, the exogenous addition of AA rescued VEGF-induced HRMVEC DNA synthesis, migration, and tube formation from inhibition by down-regulation of cPLA(2). Inhibition of Src, PLD1, or PKCγ attenuated VEGF-induced cPLA(2) phosphorylation and AA release. Consistent with these findings, hypoxia induced cPLA(2) phosphorylation and activity in VEGF-Src-PLD1-PKCγ-dependent manner in a mouse model of oxygen-induced retinopathy. In addition, siRNA-mediated down-regulation of cPLA(2) levels in the retina abrogated hypoxia-induced retinal endothelial cell proliferation and neovascularization. These observations suggest that cPLA(2)-dependent AA release is required for VEGF-induced Src-PLD1-PKCγ-mediated pathological retinal angiogenesis.
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Affiliation(s)
- Qiuhua Zhang
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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126
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Chang JY. Methylmercury-induced IL-6 release requires phospholipase C activities. Neurosci Lett 2011; 496:152-6. [PMID: 21513770 DOI: 10.1016/j.neulet.2011.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 03/23/2011] [Accepted: 04/05/2011] [Indexed: 10/18/2022]
Abstract
Methylmercury (MeHg) is a neurotoxin capable of causing severe damage to the CNS, especially in the developing fetus. Glia in the CNS release a number of cytokines that are important for proper CNS development and function. We reported earlier that MeHg could induce interleukin-6 (IL-6) release in primary mouse glia. This finding is significant considering previous reports indicating that sustained IL-6 exposure could be detrimental to cerebellar granule neurons, one of the major cellular targets of MeHg cytotoxicity. By using pharmacological antagonists against phophatidycholine- and phosphoinositol-specific phospholipase C, the current study indicated that phospholipase C activity was necessary for MeHg-induced IL-6 release. Results from pharmacological antagonists further suggested that the calcium signaling initiated by phospholipase C appeared essential for this event. In contrast, protein kinase C activity did not appear to be important. Even though mitogen-activated protein kinases were important for IL-6 release in some experimental systems, these enzymes did not appear to be required for MeHg-induced IL-6 release in glia. Based on these data and those reported by us and others, there is a possibility that MeHg-induced phospholipase C activation initiates a calcium signaling that causes phospholipase A(2) activation. This, in turn, leads to arachidonic acid and lysophosphatidyl choline generation, both of which are potent inducers for IL-6 release.
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Affiliation(s)
- Jason Y Chang
- Department of Neurobiology and Developmental Sciences, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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127
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Tanabe Y, Saito M, Morikawa Y, Kamataki A, Sawai T, Hirose M, Nakayama K. Inhibition of untransformed prostaglandin H(2) production and stretch-induced contraction of rabbit pulmonary arteries by indoxam, a selective secretory phospholipase A(2) inhibitor. J Pharmacol Sci 2011; 115:525-31. [PMID: 21422723 DOI: 10.1254/jphs.10247sc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Involvement of secretory phospholipase A(2) (sPLA(2)) in the stretch-induced production of untransformed prostaglandin H(2) (PGH(2)) in the endothelium of rabbit pulmonary arteries was investigated. The stretch-induced contraction was significantly inhibited by indoxam, a selective inhibitor for sPLA(2), and NS-398, a selective inhibitor for cyclooxygenase-2 (COX-2). Indoxam inhibited the RGD-sensitive-integrin-independent production of untransformed PGH(2), but did not affect the RGD-sensitive-integrin-dependent production of thromboxane A(2) (TXA(2)). These results suggest that the stretch-induced contraction and untransformed PGH(2) production was mediated by sPLA(2)-COX-2 pathway, making it a new possible target for pharmacological intervention of pulmonary artery contractility.
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Affiliation(s)
- Yoshiyuki Tanabe
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Iwate Medical University, Japan.
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128
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Mete A, Andrews G, Bernstein M, Connolly S, Hartopp P, Jackson CG, Lewis R, Martin I, Murray D, Riley R, Robinson DH, Smith GM, Wells E, Withnall WJ. Design of novel and potent cPLA2α inhibitors containing an α-methyl-2-ketothiazole as a metabolically stable serine trap. Bioorg Med Chem Lett 2011; 21:3128-33. [PMID: 21450464 DOI: 10.1016/j.bmcl.2011.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/01/2011] [Accepted: 03/02/2011] [Indexed: 11/29/2022]
Abstract
We report the design of novel, potent cPLA(2)α inhibitors that possess an α-methyl-2-ketothiazole that acts as a serine-reactive moiety. We describe the optimization of the series for potency and metabolic stability towards ketone reduction. This was achieved by attenuating the reactivity of the ketone using a combination of electronic and steric effects.
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Affiliation(s)
- Antonio Mete
- Department of Medicinal Chemistry, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire LE11 5RH, United Kingdom.
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129
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Cheng SE, Lin CC, Lee IT, Hsu CK, Kou YR, Yang CM. Cigarette smoke extract regulates cytosolic phospholipase A2expression via NADPH oxidase/MAPKs/AP-1 and p300 in human tracheal smooth muscle cells. J Cell Biochem 2011; 112:589-99. [DOI: 10.1002/jcb.22949] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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130
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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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131
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Zhu CL, Cao YH, Zhang R, Song Y, Liu WY, Pan F, Li Y, Zhu Y, Liu F, Wu JG. Stimulatory effect of LPS and feedback effect of PGE2 on IL-27 production. Scand J Immunol 2011; 72:469-75. [PMID: 21044121 DOI: 10.1111/j.1365-3083.2010.02460.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Interleukin (IL)-27 is a new member of the IL-6/IL-12 family, composed of two subunits, the Epstein-Barr virus-induced gene 3 (EBI3) and p28 chains (p28), and produced by activated monocytes and dendritic cells. IL-27 plays an important role in the regulation of differentiation of naive T helper cells and has diverse effects on innate immune cells. However, the pro-inflammatory mechanisms of IL-27 are still not well known. In this study, we investigated the effect of lipopolysaccharide (LPS) on the production of IL-27. We found that LPS-stimulated IL-27 production was in a dose-dependent and time-dependent manner in THP-1 cells. We have also shown that IL-27 induced PGE2 production and COX-2 gene expression at the level of mRNA as well as protein. Moreover, we found feed back effect of PGE2 on the production of IL-27 in THP-1 cells. The results suggest that PGE2 significantly inhibits LPS-induced IL-27 production, without affecting basal IL-27 expression. Further experiment suggests that PGE2 and LPS regulate IL-27 through NF-κB pathway. Our findings may have wide implication for IL-27 in inflammatory diseases.
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Affiliation(s)
- C L Zhu
- Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Wuhan, China
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132
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Kandasamy P, Zarini S, Chan ED, Leslie CC, Murphy RC, Voelker DR. Pulmonary surfactant phosphatidylglycerol inhibits Mycoplasma pneumoniae-stimulated eicosanoid production from human and mouse macrophages. J Biol Chem 2011; 286:7841-7853. [PMID: 21205826 DOI: 10.1074/jbc.m110.170241] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mycoplasma pneumoniae is a human pathogen causing respiratory infections that are also associated with serious exacerbations of chronic lung diseases. Membranes and lipoproteins from M. pneumoniae induced a 4-fold increase in arachidonic acid (AA) release from RAW264.7 and a 2-fold increase in AA release from primary human alveolar macrophages. The bacterial lipoprotein mimic and TLR2/1 agonist Pam3Cys and the TLR2/6 agonist MALP-2 produced effects similar to those elicited by M. pneumoniae in macrophages by inducing the phosphorylation of p38(MAPK) and p44/42(ERK1/2) MAP kinases and cyclooxygenase-2 (COX-2) expression. M. pneumoniae induced the generation of prostaglandins PGD(2) and PGE(2) from RAW264.7 cells and thromboxane B(2) (TXB(2)) from human alveolar macrophages. Anti-TLR2 antibody completely abolished M. pneumoniae-induced AA release and TNFα secretion from RAW264.7 cells and human alveolar macrophages. Disruption of the phosphorylation of p44/42(ERK1/2) or inactivation of cytosolic phospholipase A(2)α (cPLA(2)α) completely inhibited M. pneumoniae-induced AA release from macrophages. The minor pulmonary surfactant phospholipid, palmitoyl-oleoyl-phosphatidylglycerol (POPG), antagonized the proinflammatory actions of M. pneumoniae, Pam3Cys, and MALP-2 by reducing the production of AA metabolites from macrophages. The effect of POPG was specific, insofar as saturated PG, and saturated and unsaturated phosphatidylcholines did not have significant effect on M. pneumoniae-induced AA release. Collectively, these data demonstrate that M. pneumoniae stimulates the production of eicosanoids from macrophages through TLR2, and POPG suppresses this pathogen-induced response.
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Affiliation(s)
| | - Simona Zarini
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011
| | | | - Christina C Leslie
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011; Pediatrics, National Jewish Health, Denver, Colorado, 80206 and
| | - Robert C Murphy
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011
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Lee YM. A Study on the Mechanism of Immunomodulating Effects of Moxifloxacin in Oleic Acid-Induced Acute Lung Injury. Tuberc Respir Dis (Seoul) 2011. [DOI: 10.4046/trd.2011.71.2.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Young Man Lee
- Department of Physiology, The Catholic University of Daegu School of Medicine, Daegu, Korea
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134
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Yano T, Fujioka D, Saito Y, Kobayashi T, Nakamura T, Obata JE, Kawabata K, Watanabe K, Watanabe Y, Mishina H, Tamaru S, Kugiyama K. Group V secretory phospholipase A2 plays a pathogenic role in myocardial ischaemia-reperfusion injury. Cardiovasc Res 2010; 90:335-43. [PMID: 21169294 DOI: 10.1093/cvr/cvq399] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIMS Group V secretory phospholipase A(2) (sPLA(2)-V) is highly expressed in the heart. This study examined (i) the role of sPLA(2)-V in myocardial ischaemia-reperfusion (I/R) injury and (ii) the cooperative action of sPLA(2)-V and cytosolic PLA(2) (cPLA(2)) in myocardial I/R injury, using sPLA(2)-V knockout (sPLA(2)V(-/-)) mice. METHODS AND RESULTS Myocardial I/R injury was created by 1 h ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. The sPLA(2)V(-/-) mice had a 44% decrease in myocardial infarct size, a preservation of echocardiographic LV function (%fractional shortening: 40 ± 3.5 vs. 21 ± 4.6, respectively), and lower content of leucotriene B(4) (LTB(4)) and thromboxane B(2) (TXB(2)) (40 and 37% lower, respectively) in the ischaemic myocardium after I/R compared with wild-type (WT) mice. Intraperitoneal administration of AACOCF3 or MAFP, inhibitors of cPLA(2) activity, decreased myocardial infarct size and myocardial content of LTB(4) and TXB(2) in both genotyped mice. The decrease in myocardial infarct size and content of LTB(4) and TXB(2) after cPLA(2) inhibitor administration was greater in WT mice than in sPLA(2)V(-/-) mice. I/R increased phosphorylation of extracellular signal-related kinase 1/2, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases in the ischaemic myocardium in association with cPLA(2) phosphorylation. The I/R-induced increase in the phosphorylation of p38 and cPLA(2) was less in sPLA(2)-V(-/-) mice than in WT mice. Pretreatment with the p38 inhibitor SB202190 suppressed an increase in cPLA(2) phosphorylation after I/R in WT mice. CONCLUSION sPLA(2)-V plays an important role in the pathogenesis of myocardial I/R injury partly in concert with the activation of cPLA(2).
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Affiliation(s)
- Toshiaki Yano
- Department of Internal Medicine II, Faculty of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Yamanashi, Chuo 409-3898, Japan
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135
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Mayahara K, Yamaguchi A, Sakaguchi M, Igarashi Y, Shimizu N. Effect of Ga-Al-As laser irradiation on COX-2 and cPLA2-alpha expression in compressed human periodontal ligament cells. Lasers Surg Med 2010; 42:489-93. [PMID: 20662025 DOI: 10.1002/lsm.20871] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Prostaglandin E(2) (PGE(2)), which has bone-resorptive activity, is produced by human periodontal ligament (PDL) cells in response to mechanical stress. We previously reported that low level laser (LLL) irradiation inhibited PGE(2) production in PDL cells in response to mechanical stress; however, the mechanism underlying this inhibitory effect was unclear. Thus, we sought to determine the mechanism underlying the inhibitory effect of LLL on PGE(2) production in compressed PDL cells. STUDY DESIGN/MATERIALS AND METHODS A compressive force of 2.0 g/cm(2) was applied for 24 hours to human PDL cells obtained from premolars extracted for orthodontic treatment. LLL irradiation (Ga-Al-As laser, 830 nm, 3.82 J/cm(2)) was applied 6 hours before, 1 hour before, and immediately after the application of compressive force. The mRNA expression of COX-2 and cPLA(2)-alpha was then examined by real-time PCR. RESULTS LLL irradiation significantly inhibited COX-2 and cPLA(2)-alpha mRNA expression, which was increased in response to the application of a compressive force. Moreover, LLL irradiation immediately after compression had the strongest inhibitory effect on the expression of these genes. CONCLUSIONS The inhibition of PGE(2) production by LLL irradiation in compressed PDL cells may be due to the inhibition of COX-2 and cPLA(2)-alpha expression and is most pronounced immediately after the application of a compressive force.
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Affiliation(s)
- Kotoe Mayahara
- Department of Orthodontics, Nihon University School of Dentistry, 1-8-13 Kanda, Surugadai, Chiyoda-Ku, Tokyo 101-8310, Japan.
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Caiazza F, McCarthy NS, Young L, Hill ADK, Harvey BJ, Thomas W. Cytosolic phospholipase A2-α expression in breast cancer is associated with EGFR expression and correlates with an adverse prognosis in luminal tumours. Br J Cancer 2010; 104:338-44. [PMID: 21119660 PMCID: PMC3031888 DOI: 10.1038/sj.bjc.6606025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: The eicosanoid signalling pathway promotes the progression of malignancies through the production of proliferative prostaglandins (PGs). Cytosolic phospholipase A2α (cPLA2α) activity provides the substrate for cyclooxygenase-dependent PG release, and we have previously found that cPLA2α expression correlated with EGFR/HER2 over-expression in a small number of breast cancer cell lines. Methods: The importance of differential cPLA2α activity in clinical breast cancer was established by relating the expression of cPLA2α in tissue samples from breast cancer patients, and two microarray-based gene expression datasets to different clinicopathological and therapeutic parameters. Results: High cPLA2α mRNA expression correlated with clinical parameters of poor prognosis, which are characteristic of highly invasive tumours of the HER2-positive and basal-like subtype, including low oestrogen receptor expression and high EGFR expression. High cPLA2α expression decreased overall survival in patients with luminal cancers, and correlated with a reduced effect of tamoxifen treatment. The cPLA2α expression was an independent predictive parameter of poor response to endocrine therapy in the first 5 years of follow-up. Conclusion: This study shows a role of cPLA2α in luminal breast cancer progression, in which the enzyme could represent a novel therapeutic target and a predictive marker.
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Affiliation(s)
- F Caiazza
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland
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137
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Bravo E, Napolitano M, Valentini SB, Quattrucci S. Neutrophil unsaturated fatty acid release by GM-CSF is impaired in cystic fibrosis. Lipids Health Dis 2010; 9:129. [PMID: 21059219 PMCID: PMC2988788 DOI: 10.1186/1476-511x-9-129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 11/08/2010] [Indexed: 01/11/2023] Open
Abstract
Dysregulated inflammation in cystic fibrosis (CF) is attributed to an altered production of inflammatory mediators derived from polyunsaturated lipids. In comparison to the arachidonic acid (AA) cascade, little is known about the modulation of docosahexaenoic acid (DHA) membrane release. We compared data on neutrophil DHA- and AA- release from both control (CT) and patients with CF using [3H]AA or [14C]DHA as a markers for, respectively, AA and DHA- release. Granulocyte-macrophage-colony stimulating factor stimulated DHA release from CT, but not CF, neutrophils. Comparison showed that both [14C]DHA and [3H]AA liberated after stimulation was higher in CT than in CF neutrophils. Since bioactive mediators derived from DHA are resolving factors and those derived from AA are both pro- and anti- inflammatory, these results suggest that CF is associated with a reduction of the release of PUFA-precursors of lipooxygenated resolving mediators. This leads to the hypothesis that defects in the resolving factors production could contribute to the inflammatory dysregulated processes in CF. Furthermore, the methodology used may help to improve knowledge on the regulation and resolution of inflammation.
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Affiliation(s)
- Elena Bravo
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena, 199-00161 Roma, Italy.
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138
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Huang WC, Chen ST, Chang WC, Chang KY, Chang WC, Chen BK. Involvement of aryl hydrocarbon receptor nuclear translocator in EGF-induced c-Jun/Sp1-mediated gene expression. Cell Mol Life Sci 2010; 67:3523-33. [PMID: 20508969 PMCID: PMC11115555 DOI: 10.1007/s00018-010-0392-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 11/27/2022]
Abstract
Aryl hydrocarbon receptor nuclear translocator (ARNT) binds to other basic helix-loop-helix Per/ARNT/Sim (bHLH-PAS) proteins to form functional transcriptional complexes in order to regulate specific biological pathways. Here, we report a novel mechanism that upon EGF treatment, ARNT associated with non-bHLH-PAS transcription factors, c-Jun/Sp1, and regulated gene expression, through forming a c-Jun/ARNT/Sp1 complex and binding to the Sp1 site of the gene promoter. EGF-induced promoter activity and the mRNA level of 12(S)-lipoxygenase as well as the association between c-Jun and Sp1 were reduced by ARNT knockdown. Notably, dominant negative c-Jun mutant, TAM-67, blocked ARNT-mediated 12(S)-lipoxygenase expression, demonstrating that c-Jun was responsible for the transcriptional activation. Moreover, ARNT knockdown also inhibited other EGF-induced c-Jun/Sp1 mediated gene expression, such as p21( WAF1/CIP1 ). Our results reveal a novel mechanism by which ARNT acts as a modulator to bridge the c-Jun/Sp1 interaction and plays a role in EGF-mediated gene expression under normoxic conditions.
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Affiliation(s)
- Wan-Chen Huang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 701 Taiwan, ROC
| | - Shu-Ting Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 701 Taiwan, ROC
| | - Wei-Chiao Chang
- Graduate Institute of Medical Genetics, Kaohsiung Medical University, 100 Tz-You First Road, Kaohsiung, 807 Taiwan, ROC
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, ROC
| | - Kwang-Yu Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, 701 Taiwan, ROC
| | - Wen-Chang Chang
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 701 Taiwan, ROC
- Center for Gene Regulation and Signal Transduction Research, National Cheng Kung University, Tainan, 701 Taiwan, ROC
- Institute of Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, 701 Taiwan, ROC
| | - Ben-Kuen Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 701 Taiwan, ROC
- Center for Gene Regulation and Signal Transduction Research, National Cheng Kung University, Tainan, 701 Taiwan, ROC
- Institute of Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, 701 Taiwan, ROC
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139
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Lim SC, Cho H, Lee TB, Choi CH, Min YD, Kim SS, Kim KJ. Impacts of cytosolic phospholipase A2, 15-prostaglandin dehydrogenase, and cyclooxygenase-2 expressions on tumor progression in colorectal cancer. Yonsei Med J 2010; 51:692-9. [PMID: 20635443 PMCID: PMC2908865 DOI: 10.3349/ymj.2010.51.5.692] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE In addition to cyclooxygenase-2 (COX-2) which is related to prostaglandin E2 synthesis, other enzymes such as cytosolic phospholipase A2 (cPLA2), microsomal prostaglandin E2 synthase-1 (mPGES-1), and 15-prostaglandin dehydrogenase (15-PGDH) have been suggested to be related to carcinogenesis of colorectal cancer (CRC). The aim of this study was to investigate the roles of cPLA2, COX-2, mPGES-1, and 15-PGDH in tumor progression. MATERIALS AND METHODS cPLA2, COX-2, mPGES-1, 15-PGDH, and vascular endothelial growth factor (VEGF) expressions were immunohistochemically examined in 89 CRC, and their expressions were compared with each other or clinicopathologic parameters as well as VEGF as tumor progression parameters. RESULTS cPLA2 was expressed in 54.5%, COX-2 in 80.5%, mPGES-1 in 96.4%, 15-PGDH in 46.1%, and VEGF in 65.9%. The expression of cPLA2 correlated with VEGF expression. COX-2 expression was correlated with the depth of invasion, tumor stage, cPLA2, and VEGF expressions. Moreover, VEGF revealed the highest expression in the tissues positive for both cPLA2 and COX-2. Furthermore, 15-PGDH expression was inversely correlated with VEGF expression. CONCLUSION The present study demonstrates that cPLA2 and mPGES-1, in addition to COX-2, are constitutively overexpressed, and that 15-PGDH might be attenuated in colorectal cancer. Furthermore, cPLA2 and 15-PGDH as well as COX-2 could have an important role in tumor progression.
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Affiliation(s)
- Sung Chul Lim
- Department of Pathology, Chosun University, Gwangju, Korea
- Research Center for Resistant Cells, Chosun University, Gwangju, Korea
| | - Hoon Cho
- Research Center for Resistant Cells, Chosun University, Gwangju, Korea
- Department of Polymer Science & Engineering, Chosun University, Gwangju, Korea
| | - Tae Bum Lee
- Research Center for Resistant Cells, Chosun University, Gwangju, Korea
| | - Cheol Hee Choi
- Research Center for Resistant Cells, Chosun University, Gwangju, Korea
| | - Young Don Min
- Department of Surgery, College of Medicine, Chosun University, Gwangju, Korea
| | - Sung Soo Kim
- Department of Surgery, College of Medicine, Chosun University, Gwangju, Korea
| | - Kyung Jong Kim
- Department of Surgery, College of Medicine, Chosun University, Gwangju, Korea
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140
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Leopoldini M, Russo N, Toscano M. Favored Reaction Mechanism of Calcium-Dependent Phospholipase A2. Insights from Density Functional Exploration. J Phys Chem B 2010; 114:11584-93. [DOI: 10.1021/jp1003819] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Monica Leopoldini
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
| | - Nino Russo
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
| | - Marirosa Toscano
- Dipartimento di Chimica and Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite-Centro d’Eccellenza MIUR, Università della Calabria, I-87030 Arcavacata di Rende (CS), Italy
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141
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Carrichon L, Picciocchi A, Debeurme F, Defendi F, Beaumel S, Jesaitis AJ, Dagher MC, Stasia MJ. Characterization of superoxide overproduction by the D-Loop(Nox4)-Nox2 cytochrome b(558) in phagocytes-Differential sensitivity to calcium and phosphorylation events. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:78-90. [PMID: 20708598 DOI: 10.1016/j.bbamem.2010.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 08/02/2010] [Accepted: 08/03/2010] [Indexed: 11/29/2022]
Abstract
NADPH oxidase is a crucial element of phagocytes involved in microbicidal mechanisms. It becomes active when membrane-bound cytochrome b(558), the redox core, is assembled with cytosolic p47(phox), p67(phox), p40(phox), and rac proteins to produce superoxide, the precursor for generation of toxic reactive oxygen species. In a previous study, we demonstrated that the potential second intracellular loop of Nox2 was essential to maintaining NADPH oxidase activity by controlling electron transfer from FAD to O(2). Moreover, replacement of this loop by the Nox4-D-loop (D-loop(Nox4)-Nox2) in PLB-985 cells induced superoxide overproduction. In the present investigation, we demonstrated that both soluble and particulate stimuli were able to induce this superoxide overproduction. Superoxide overproduction was also observed after phosphatidic acid activation in a purified cell-free-system assay. The highest oxidase activity was obtained after ionomycin and fMLF stimulation. In addition, enhanced sensitivity to Ca(2+) influx was shown by thapsigargin, EDTA, or BTP2 treatment before fMLF activation. Mutated cytochrome b(558) was less dependent on phosphorylation triggered by ERK1/2 during fMLF or PMA stimulation and by PI3K during OpZ stimulation. The superoxide overproduction of the D-loop(Nox4)-Nox2 mutant may come from a change of responsiveness to intracellular Ca(2+) level and to phosphorylation events during oxidase activation. Finally the D-loop(Nox4)-Nox2-PLB-985 cells were more effective against an attenuated strain of Pseudomonas aeruginosa compared to WT-Nox2 cells. The killing mechanism was biphasic, an early step of ROS production that was directly bactericidal, and a second oxidase-independent step related to the amount of ROS produced in the first step.
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Affiliation(s)
- Laure Carrichon
- Centre Diagnostic et Recherche sur la Granulomatose septique chronique CGD, TheREx-TIMC/Imag UMR CNRS 5525, CHU and Université Joseph Fourier, 38043 Grenoble Cedex 9, France
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142
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Ghomashchi F, Naika GS, Bollinger JG, Aloulou A, Lehr M, Leslie CC, Gelb MH. Interfacial kinetic and binding properties of mammalian group IVB phospholipase A2 (cPLA2beta) and comparison with the other cPLA2 isoforms. J Biol Chem 2010; 285:36100-11. [PMID: 20705608 DOI: 10.1074/jbc.m110.165647] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cytosolic (group IV) phospholipase A(2) (cPLA(2)s) family contains six members. We have prepared recombinant proteins for human α, mouse β, human γ, human δ, human ε, and mouse ζ cPLA(2)s and have studied their interfacial kinetic and binding properties in vitro. Mouse cPLA(2)β action on phosphatidylcholine vesicles is activated by anionic phosphoinositides and cardiolipin but displays a requirement for Ca(2+) only in the presence of cardiolipin. This activation pattern is explained by the effects of anionic phospholipids and Ca(2+) on the interfacial binding of mouse cPLA(2)β and its C2 domain to vesicles. Ca(2+)-dependent binding of mouse cPLA(2)β to cardiolipin-containing vesicles requires a patch of basic residues near the Ca(2+)-binding surface loops of the C2 domain, but binding to phosphoinositide-containing vesicles does not depend on any specific cluster of basic residues. Human cPLA(2)δ also displays Ca(2+)- and cardiolipin-enhanced interfacial binding and activity. The lysophospholipase, phospholipase A(1), and phospholipase A(2) activities of the full set of mammalian cPLA(2)s were quantified. The relative level of these activities is very different among the isoforms, and human cPLA(2)δ stands out as having relatively high phospholipase A(1) activity. We also tested the susceptibility of all cPLA(2) family members to a panel of previously reported inhibitors of human cPLA(2)α and analogs of these compounds. This led to the discovery of a potent and selective inhibitor of mouse cPLA(2)β. These in vitro studies help determine the regulation and function of the cPLA(2) family members.
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Affiliation(s)
- Farideh Ghomashchi
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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143
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Hawkins BJ, Irrinki KM, Mallilankaraman K, Lien YC, Wang Y, Bhanumathy CD, Subbiah R, Ritchie MF, Soboloff J, Baba Y, Kurosaki T, Joseph SK, Gill DL, Madesh M. S-glutathionylation activates STIM1 and alters mitochondrial homeostasis. ACTA ACUST UNITED AC 2010; 190:391-405. [PMID: 20679432 PMCID: PMC2922639 DOI: 10.1083/jcb.201004152] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Oxidant stress induces constitutive calcium entry by tacking glutathiones onto the Orai CRAC channel activator STIM1. Oxidant stress influences many cellular processes, including cell growth, differentiation, and cell death. A well-recognized link between these processes and oxidant stress is via alterations in Ca2+ signaling. However, precisely how oxidants influence Ca2+ signaling remains unclear. Oxidant stress led to a phenotypic shift in Ca2+ mobilization from an oscillatory to a sustained elevated pattern via calcium release–activated calcium (CRAC)–mediated capacitive Ca2+ entry, and stromal interaction molecule 1 (STIM1)– and Orai1-deficient cells are resistant to oxidant stress. Functionally, oxidant-induced Ca2+ entry alters mitochondrial Ca2+ handling and bioenergetics and triggers cell death. STIM1 is S-glutathionylated at cysteine 56 in response to oxidant stress and evokes constitutive Ca2+ entry independent of intracellular Ca2+ stores. These experiments reveal that cysteine 56 is a sensor for oxidant-dependent activation of STIM1 and demonstrate a molecular link between oxidant stress and Ca2+ signaling via the CRAC channel.
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Affiliation(s)
- Brian J Hawkins
- Department of Biochemistry, Temple University, Philadelphia, PA 19140, USA
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144
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Lee CW, Lee IT, Lin CC, Lee HC, Lin WN, Yang CM. Activation and induction of cytosolic phospholipase A2 by IL-1beta in human tracheal smooth muscle cells: role of MAPKs/p300 and NF-kappaB. J Cell Biochem 2010; 109:1045-56. [PMID: 20069553 DOI: 10.1002/jcb.22488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cytosolic phospholipase A(2) (cPLA(2)) plays a pivotal role in mediating agonist-induced arachidonic acid (AA) release for prostaglandin (PG) synthesis during inflammation triggered by IL-1beta. However, the mechanisms underlying IL-1beta-induced cPLA(2) expression and PGE(2) synthesis in human tracheal smooth muscle cells (HTSMCs) remain unknown. IL-1beta-induced cPLA(2) protein and mRNA expression, PGE(2) production, or phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK1/2, which was attenuated by pretreatment with the inhibitors of MEK1/2 (U0126), p38 MAPK (SB202190), and JNK1/2 (SP600125) or transfection with siRNAs of MEK1, p42, p38, and JNK2. IL-1beta-induced cPLA(2) expression was also inhibited by pretreatment with a NF-kappaB inhibitor, helenalin or transfection with siRNA of NIK, IKKalpha, or IKKbeta. IL-beta-induced NF-kappaB translocation was blocked by pretreatment with helenalin, but not U0126, SB202190, and SP600125. In addition, transfection with p300 siRNA blocked cPLA(2) expression induced by IL-1beta. Moreover, p300 was associated with the cPLA(2) promoter, which was dynamically linked to histone H4 acetylation stimulated by IL-1beta. These results suggest that in HTSMCs, activation of MAPKs, NF-kappaB, and p300 are essential for IL-1beta-induced cPLA(2) expression and PGE(2) secretion.
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Affiliation(s)
- Chiang-Wen Lee
- Division of Basic Medical Sciences, Department of Nursing, Chang Gung Institute of Technology, Chia-Yi, Taiwan
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145
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Extracellular phospholipases in atherosclerosis. Biochimie 2010; 92:594-600. [DOI: 10.1016/j.biochi.2010.02.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/02/2010] [Indexed: 01/01/2023]
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146
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Suzuki Y, Inoue T, Ra C. NSAIDs, Mitochondria and Calcium Signaling: Special Focus on Aspirin/Salicylates. Pharmaceuticals (Basel) 2010; 3:1594-1613. [PMID: 27713319 PMCID: PMC4033999 DOI: 10.3390/ph3051594] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 04/26/2010] [Accepted: 05/14/2010] [Indexed: 12/21/2022] Open
Abstract
Aspirin (acetylsalicylic acid) is a well-known nonsteroidal anti-inflammatory drug (NSAID) that has long been used as an anti-pyretic and analgesic drug. Recently, much attention has been paid to the chemopreventive and apoptosis-inducing effects of NSAIDs in cancer cells. These effects have been thought to be primarily attributed to the inhibition of cyclooxygenase activity and prostaglandin synthesis. However, recent studies have demonstrated unequivocally that certain NSAIDs, including aspirin and its metabolite salicylic acid, exert their anti-inflammatory and chemopreventive effects independently of cyclooxygenase activity and prostaglandin synthesis inhibition. It is becoming increasingly evident that two potential common targets of NSAIDs are mitochondria and the Ca2+ signaling pathway. In this review, we provide an overview of the current knowledge regarding the roles of mitochondria and Ca2+ in the apoptosis-inducing effects as well as some side effects of aspirin, salicylates and other NSAIDs, and introducing the emerging role of L-type Ca2+ channels, a new Ca2+ entry pathway in non-excitable cells that is up-regulated in human cancer cells.
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Affiliation(s)
- Yoshihiro Suzuki
- Division of Molecular Cell Immunology and Allergology, Nihon University Graduate School of Medical Science, Tokyo, Japan.
| | - Toshio Inoue
- Division of Molecular Cell Immunology and Allergology, Nihon University Graduate School of Medical Science, Tokyo, Japan
| | - Chisei Ra
- Division of Molecular Cell Immunology and Allergology, Nihon University Graduate School of Medical Science, Tokyo, Japan
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147
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Cañadillas S, Canalejo R, Rodriguez-Ortiz ME, Martinez-Moreno JM, Estepa JC, Zafra R, Perez J, Muñoz-Castañeda JR, Canalejo A, Rodriguez M, Almaden Y. Upregulation of parathyroid VDR expression by extracellular calcium is mediated by ERK1/2-MAPK signaling pathway. Am J Physiol Renal Physiol 2010; 298:F1197-204. [DOI: 10.1152/ajprenal.00529.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously demonstrated that the activation of rat parathyroid calcium-sensing receptor (CaSR) upregulates VDR expression in vivo (Garfia B, Cañadillas S, Luque F, Siendones E, Quesada M, Almadén Y, Aguilera-Tejero E, Rodríguez M. J Am Soc Nephrol 13: 2945–2952, 2002; Rodriguez ME, Almaden Y, Cañadillas S, Canalejo A, Siendones E, Lopez I, Aguilera-Tejero E, Martin D, Rodriguez M. Am J Physiol Renal Physiol 292: F1390–F1395, 2007). The present study was designed to characterize the signaling system that mediates the stimulation of parathyroid VDR gene expression by extracellular calcium. Experiments were performed in vitro by the incubation of rat parathyroid glands and in vivo with normal and uremic (Nx) rats receiving injections of CaCl2or EDTA to obtain hypercalcemic or hypocalcemic clamps. A high calcium concentration increased VDR expression. The addition of arachidonic acid (AA) to the low-calcium medium produced an increase in VDR mRNA of the same magnitude as that observed with high calcium. The addition of ionophore to the low-calcium medium also increased VDR mRNA expression. High calcium or the addition of AA to the low-calcium medium induced the activation (phosphorylation) of ERK1/2-MAPK. The specific inhibition of the ERK1/2-MAPK activity prevented the stimulation of VDR expression by high calcium or AA. These results suggest that AA regulates parathyroid VDR gene expression through the activation of the ERK1/2-MAPK. CaSR activation induced the activation of transcription factor Sp1, but not of NF-κB p50 or p65 or activator protein-1. The addition of AA to the low-calcium medium increased specific DNA-binding activity of Sp1 to almost the same level as high calcium, which was prevented by the inhibition of ERK1/2. Furthermore, mithramycin A (a Sp1 inhibitor) prevented the upregulation of VDR mRNA by high calcium. Finally, both sham and Nx hypercalcemic rats showed similar increased levels of VDR mRNA compared with sham and Nx hypocalcemic rats. Our results demonstrate that extracellular calcium stimulates VDR expression in parathyroid glands through the elevation of the cytosolic calcium level and the stimulation of the PLA2-AA-dependent ERK1/2-pathway. Furthermore, the transcription factor Sp1 mediates this effect.
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Affiliation(s)
- Sagrario Cañadillas
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | - Rocio Canalejo
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | - Maria Encarnacion Rodriguez-Ortiz
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | - Julio Manuel Martinez-Moreno
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | | | - Rafael Zafra
- Departmento Anatomía Patológica, and Universidad de Cordoba, Cordoba; and
| | - Jose Perez
- Departmento Anatomía Patológica, and Universidad de Cordoba, Cordoba; and
| | - Juan Rafael Muñoz-Castañeda
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | - Antonio Canalejo
- Departmento Biología Ambiental y Salud Publica, Universidad de Huelva, Huelva, Spain
| | - Mariano Rodriguez
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
| | - Yolanda Almaden
- Unidad de Investigacion, Servicio de Nefrologia, Red in ren, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia,
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Buttar NS, DeMars CJ, Lomberk G, Ilyas SI, Bonilla-Velez J, Achra S, Rashtak S, Wang KK, Fernandez-Zapico ME, Urrutia R. Distinct role of Kruppel-like factor 11 in the regulation of prostaglandin E2 biosynthesis. J Biol Chem 2010; 285:11433-44. [PMID: 20154088 PMCID: PMC2857022 DOI: 10.1074/jbc.m109.077065] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 02/02/2010] [Indexed: 12/15/2022] Open
Abstract
Kruppel-like factor (KLF) proteins are emerging as key regulators of lipid metabolism, diabetes, and the biosynthesis of immunological cytokines. However, their role in the synthesis of prostaglandins, widely known biochemical mediators that act in a myriad of cell biological processes remain poorly understood. Consequently, in this study a comprehensive investigation at the cellular, biochemical, and molecular levels reveal that KLF11 inhibits prostaglandin E(2) synthesis via transcriptional silencing of the promoter of its biosynthetic enzyme, cytosolic phospholipase A2alpha. Mechanistically, KLF11 accomplishes this function by binding to the promoter via specific GC-rich sites and recruiting the Sin3-histone deacetylase chromatin remodeling complex. Further functional characterization reveals that this function of KLF11 can be reversed by epidermal growth factor receptor-AKT-mediated post-translational modification of threonine 56, a residue within its Sin3-binding domain. This is the first evidence supporting a relevant role for any KLF protein in doing both: transcriptionally inhibiting prostaglandin biosynthesis and its reversibility by an epidermal growth factor receptor-AKT signaling-mediated posttranslational mechanisms.
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Affiliation(s)
- Navtej S Buttar
- Division of Gastroenterology, Mayo Clinic, Rochester, Minnesota 55902, USA.
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Mirshafiey A, Jadidi-Niaragh F. Immunopharmacological role of the Leukotriene Receptor Antagonists and inhibitors of leukotrienes generating enzymes in Multiple Sclerosis. Immunopharmacol Immunotoxicol 2010; 32:219-27. [DOI: 10.3109/08923970903283662] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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150
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Meliton AY, Muñoz NM, Meliton LN, Binder DC, Osan CM, Zhu X, Dudek SM, Leff AR. Cytosolic group IVa phospholipase A2 mediates IL-8/CXCL8-induced transmigration of human polymorphonuclear leukocytes in vitro. JOURNAL OF INFLAMMATION-LONDON 2010; 7:14. [PMID: 20298597 PMCID: PMC2848033 DOI: 10.1186/1476-9255-7-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 03/18/2010] [Indexed: 12/18/2022]
Abstract
Background Cytosolic gIVaPLA2 is a critical enzyme in the generation of arachidonate metabolites and in induction of β2-integrin adhesion in granulocytes. We hypothesized that gIVaPLA2 activation also is an essential downstream step for post adhesive migration of PMN in vitro. Methods Migration of PMNs caused by IL-8/CXCL8 was assessed using a transwell migration chamber. PMNs were pretreated with two structurally unrelated inhibitors of gIVaPLA2, arachidonyl trifluoromethylketone (TFMK) or pyrrophenone, prior to IL-8/CXCL8 exposure. The fraction of migrated PMNs present in the lower chamber was measured as total myeloperoxidase content. GIVaPLA2 enzyme activity was analyzed using [14C-PAPC] as specific substrate F-actin polymerization and cell structure were examined after rhodamine-phalloidin staining. Results IL-8/CXCL8-induced migration of PMNs was elicited in concentration- and time-dependent manner. Time-related phosphorylation and translocation of cytosolic gIVaPLA2 to the nucleus was observed for PMNs stimulated with IL-8/CXCL8 in concentration sufficient to cause upstream phosphorylation of MAPKs (ERK-1/2 and p38) and Akt/PKB. Inhibition of gIVaPLA2 corresponded to the magnitude of blockade of PMN migration. Neither AA nor LTB4 secretion was elicited following IL-8/CXCL8 activation. In unstimulated PMNs, F-actin was located diffusely in the cytosol; however, a clear polarized morphology with F-actin-rich ruffles around the edges of the cell was observed after activation with IL-8/CXCL8. Inhibition of gIVaPLA2 blocked change in cell shape and migration caused by IL-8/CXCL8 but did not cause F-actin polymerization or translocation of cytosolic F-actin to inner leaflet of the PMN membrane. Conclusion We demonstrate that IL-8/CXCL8 causes a) phosphorylation and translocation of cytosolic gIVaPLA2 to the nucleus, b) change in cell shape, c) polymerization of F-actin, and d) chemoattractant/migration of PMN in vitro. Inhibition of gIVaPLA2 blocks the deformability and subsequent migration of PMNs caused by IL-8/CXCL8. Our data suggest that activation of gIVaPLA2 is an essential step in PMN migration in vitro.
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Affiliation(s)
- Angelo Y Meliton
- Section of Pulmonary and Critical Care Medicine, Departments of Medicine, The University of Chicago, 5841 S Maryland Avenue, MC 6026, Chicago, IL 60637, USA.
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