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Janovicz A, Majer A, Kosztelnik M, Geiszt M, Chun J, Ishii S, Tigyi GJ, Benyó Z, Ruisanchez É. Autotaxin-lysophosphatidic acid receptor 5 axis evokes endothelial dysfunction via reactive oxygen species signaling. Exp Biol Med (Maywood) 2023; 248:1887-1894. [PMID: 37837357 PMCID: PMC10792427 DOI: 10.1177/15353702231199081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 07/29/2023] [Indexed: 10/16/2023] Open
Abstract
Lysophosphatidylcholine (LPC) is a bioactive lipid that has been shown to attenuate endothelium-dependent vasorelaxation contributing to endothelial dysfunction; however, the underlying mechanisms are not well understood. In this study, we investigated the molecular mechanisms involved in the development of LPC-evoked impairment of endothelium-dependent vasorelaxation. In aortic rings isolated from wild-type (WT) mice, a 20-min exposure to LPC significantly reduced the acetylcholine chloride (ACh)-induced vasorelaxation indicating the impairment of normal endothelial function. Interestingly, pharmacological inhibition of autotaxin (ATX) by GLPG1690 partially reversed the endothelial dysfunction, suggesting that lysophosphatidic acid (LPA) derived from LPC may be involved in the effect. Therefore, the effect of LPC was also tested in aortic rings isolated from different LPA receptor knock-out (KO) mice. LPC evoked a marked reduction in ACh-dependent vasorelaxation in Lpar1, Lpar2, and Lpar4 KO, but its effect was significantly attenuated in Lpar5 KO vessels. Furthermore, addition of superoxide dismutase reduced the LPC-induced endothelial dysfunction in WT but not in the Lpar5 KO mice. In addition, LPC increased H2O2 release from WT vessels, which was significantly reduced in Lpar5 KO vessels. Our findings indicate that the ATX-LPA-LPA5 receptor axis is involved in the development of LPC-induced impairment of endothelium-dependent vasorelaxation via LPA5 receptor-mediated reactive oxygen species production. Taken together, in this study, we identified a new pathway contributing to the development of LPC-induced endothelial dysfunction.
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Affiliation(s)
- Anna Janovicz
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
- Eötvös Loránd Research Network and Semmelweis University (ELKH-SE) Cerebrovascular and Neurocognitive Disorders Research Group, H-1052 Budapest, Hungary
| | - Aliz Majer
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
| | - Mónika Kosztelnik
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
- Eötvös Loránd Research Network and Semmelweis University (ELKH-SE) Cerebrovascular and Neurocognitive Disorders Research Group, H-1052 Budapest, Hungary
| | - Miklós Geiszt
- Department of Physiology, Faculty of Medicine, Semmelweis University, H-1094 Budapest, Hungary
| | - Jerold Chun
- Translational Neuroscience at Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Satoshi Ishii
- Department of Immunology, Graduate School of Medicine, Akita University, Akita 010-8543, Japan
| | - Gábor József Tigyi
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Zoltán Benyó
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
- Eötvös Loránd Research Network and Semmelweis University (ELKH-SE) Cerebrovascular and Neurocognitive Disorders Research Group, H-1052 Budapest, Hungary
| | - Éva Ruisanchez
- Institute of Translational Medicine, Semmelweis University, H-1094 Budapest, Hungary
- Eötvös Loránd Research Network and Semmelweis University (ELKH-SE) Cerebrovascular and Neurocognitive Disorders Research Group, H-1052 Budapest, Hungary
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Szlasa W, Zendran I, Zalesińska A, Tarek M, Kulbacka J. Lipid composition of the cancer cell membrane. J Bioenerg Biomembr 2020; 52:321-342. [PMID: 32715369 PMCID: PMC7520422 DOI: 10.1007/s10863-020-09846-4] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022]
Abstract
Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.
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Affiliation(s)
- Wojciech Szlasa
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | - Iga Zendran
- Faculty of Medicine, Wroclaw Medical University, Wrocław, Poland
| | | | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000, Nancy, France
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wrocław, Poland.
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Tsai TY, Leong IL, Cheng KS, Shiao LR, Su TH, Wong KL, Chan P, Leung YM. Lysophosphatidylcholine-induced cytotoxicity and protection by heparin in mouse brain bEND.3 endothelial cells. Fundam Clin Pharmacol 2018; 33:52-62. [PMID: 29974515 DOI: 10.1111/fcp.12399] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Tien-Yao Tsai
- Cardiovascular Division; Fu Jen Catholic University Hospital; New Taipei City Taiwan
- School of Medicine; College of Medicine; Fu Jen Catholic University; New Taipei City Taiwan
| | - Iat-Lon Leong
- Division of Cardiology; Department of Internal Medicine; Kiang Wu Hospital; Macau China
| | - Ka-Shun Cheng
- Department of Anesthesiology; China Medical University Hospital; Taichung Taiwan
- Department of Anesthesiology; The Qingdao University Yuhuangding Hospital; Yantai Shandong China
| | - Lian-Ru Shiao
- Department of Physiology; China Medical University; Taichung Taiwan
| | - Tzu-Hui Su
- Department of Anesthesiology; China Medical University Hospital; Taichung Taiwan
| | - Kar-Lok Wong
- Department of Anesthesiology; China Medical University Hospital; Taichung Taiwan
| | - Paul Chan
- Division of Cardiology; Department of Medicine; Taipei Medical University Wan Fang Hospital; Taipei Taiwan
| | - Yuk-Man Leung
- Department of Physiology; China Medical University; Taichung Taiwan
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Boxler MI, Liechti ME, Schmid Y, Kraemer T, Steuer AE. First Time View on Human Metabolome Changes after a Single Intake of 3,4-Methylenedioxymethamphetamine in Healthy Placebo-Controlled Subjects. J Proteome Res 2017; 16:3310-3320. [DOI: 10.1021/acs.jproteome.7b00294] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Martina I. Boxler
- Department of Forensic Pharmacology & Toxicology, Zurich Institute of Forensic Medicine, University of Zurich,Winterthurerstrasse 190/52, 8057 Zurich, Switzerland
| | - Matthias E. Liechti
- Psychopharmacology
Research, Division of Clinical Pharmacology and Toxicology, Department
of Biomedicine, Department of Clinical Research, University Hospital Basel, 4031 Basel, Switzerland
| | - Yasmin Schmid
- Psychopharmacology
Research, Division of Clinical Pharmacology and Toxicology, Department
of Biomedicine, Department of Clinical Research, University Hospital Basel, 4031 Basel, Switzerland
| | - Thomas Kraemer
- Department of Forensic Pharmacology & Toxicology, Zurich Institute of Forensic Medicine, University of Zurich,Winterthurerstrasse 190/52, 8057 Zurich, Switzerland
| | - Andrea E. Steuer
- Department of Forensic Pharmacology & Toxicology, Zurich Institute of Forensic Medicine, University of Zurich,Winterthurerstrasse 190/52, 8057 Zurich, Switzerland
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Wiltz DC, Han RI, Wilson RL, Kumar A, Morrisett JD, Grande-Allen KJ. Differential Aortic and Mitral Valve Interstitial Cell Mineralization and the Induction of Mineralization by Lysophosphatidylcholine In Vitro.. Cardiovasc Eng Technol 2014; 5:371-383. [PMID: 25419248 PMCID: PMC4235965 DOI: 10.1007/s13239-014-0197-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE Calcific aortic valve disease (CAVD) is a serious condition with vast uncertainty regarding the precise mechanism leading to valve calcification. This study was undertaken to examine the role of the lipid lysophosphatidylcholine (LPC) in a comparison of aortic and mitral valve cellular mineralization. METHODS The proportion of LPC in differentially calcified regions of diseased aortic valves was determined using thin layer chromatography (TLC). Next, porcine valvular interstitial cells (pVICs) from the aortic (paVICs) and mitral valve (pmVICs) were cultured with LPC (10-1 - 105 nM) and analyzed for cellular mineralization, alkaline phosphatase activity (ALPa), proliferation, and apoptosis. RESULTS TLC showed a higher percentage of LPC in calcified regions of tissue compared to non-calcified regions. In pVIC cultures, with the exception of 105 nM LPC, increasing concentrations of LPC led to an increase in phosphate mineralization. Increased levels of calcium content were exhibited at 104 nm LPC application compared to baseline controls. Compared to pmVIC cultures, paVIC cultures had greater total phosphate mineralization, ALPa, calcium content, and apoptosis, under both a baseline control and LPC-treated conditions. CONCLUSIONS This study showed that LPC has the capacity to promote pVIC calcification. Also, paVICs have a greater propensity for mineralization than pmVICs. LPC may be a key factor in the transition of the aortic valve from a healthy to diseased state. In addition, there are intrinsic differences that exist between VICs from different valves that may play a key role in heart valve pathology.
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Affiliation(s)
- Dena C. Wiltz
- Rice University, Department of Bioengineering, Houston, TX
| | - Richard I. Han
- Rice University, Department of Bioengineering, Houston, TX
- Baylor College of Medicine, Departments of Medicine and Biochemistry, Houston, TX
| | - Reid L. Wilson
- Rice University, Department of Bioengineering, Houston, TX
- Baylor College of Medicine, Departments of Medicine and Biochemistry, Houston, TX
| | - Aditya Kumar
- Rice University, Department of Bioengineering, Houston, TX
| | - Joel D. Morrisett
- Baylor College of Medicine, Departments of Medicine and Biochemistry, Houston, TX
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Tedesco E, Rigoni M, Caccin P, Grishin E, Rossetto O, Montecucco C. Calcium overload in nerve terminals of cultured neurons intoxicated by alpha-latrotoxin and snake PLA2 neurotoxins. Toxicon 2009; 54:138-44. [DOI: 10.1016/j.toxicon.2009.03.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 03/12/2009] [Accepted: 03/23/2009] [Indexed: 10/20/2022]
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Takayama M, Yao K, Wada M. The dihydropyridine calcium channel blocker benidipine prevents lysophosphatidylcholine-induced endothelial dysfunction in rat aorta. J Biomed Sci 2009; 16:57. [PMID: 19558657 PMCID: PMC2710319 DOI: 10.1186/1423-0127-16-57] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 06/26/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lysophosphatidylcholine (LPC), an atherogenic component of oxidized low-density lipoprotein, has been shown to induce the attenuation of endothelium-dependent vascular relaxation. Although benidipine, a dihydropyridine-calcium channel blocker, is known to have endothelial protective effects, the effects of benidipine on LPC-induced endothelial dysfunction remain unknown. We examined the effects of benidipine on the impairment of endothelium-dependent relaxation induced by LPC. METHODS Benidipine was administered orally to rats and aortas were then isolated. Aortic rings were treated with LPC and endothelial functions were then evaluated. Additionally, the effects of benidipine on intracellular calcium concentration ([Ca2+]i) and membrane fluidity altered by LPC in primary cultured rat aortic endothelial cells were examined. [Ca2+]i was measured using the fluorescent calcium indicator fura-2. Membrane fluidity was monitored by measuring fluorescence recovery after photobleaching. RESULTS Treatment with LPC impaired endothelial function. Benidipine prevents the impairment of relaxation induced by LPC. Acetylcholine elicited an increase in [Ca2+]i in fura-2 loaded endothelial cells. The increase in [Ca2+]i was suppressed after exposure to LPC. Plasma membrane fluidity increased following incubation with LPC. Benidipine inhibited the LPC-induced increase in membrane fluidity and impairment of increase in [Ca2+]i. CONCLUSION These results suggest that benidipine inhibited LPC-induced endothelial dysfunction by maintaining increase in [Ca2+]i. Benidipine possesses membrane stabilization properties in LPC-treated endothelial cells. It is speculated that the preservation of membrane fluidity by benidipine may play a role in the retainment of calcium mobilization. The present findings may provide new insights into the endothelial protective effects of benidipine.
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Affiliation(s)
- Makoto Takayama
- Pharmaceutical Research Center, Kyowa Hakko Kirin Co, Ltd, Sunto-gun, Shizuoka-ken, Japan.
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Identification of lysophosphatidylcholine-chlorohydrin in human atherosclerotic lesions. Lipids 2008; 43:243-9. [PMID: 18256867 DOI: 10.1007/s11745-008-3151-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 12/24/2007] [Indexed: 10/22/2022]
Abstract
Lysophosphatidylcholine (LysoPtdCho) levels are elevated in sera in patients with atherosclerosis and in atherosclerotic tissue. Previous studies have shown that reactive chlorinating species attack plasmalogens in human coronary artery endothelial cells (HCAEC), forming lysoPtdCho and lysoPtdCho-chlorohydrin (lysoPtdCho-ClOH). The results herein demonstrate for the first time that lysoPtdCho-ClOH is elevated over 60-fold in human atherosclerotic lesions. In cultured HCAEC, 18:0 lysoPtdCho-ClOH led to a statistically significant increase in P-selectin cell-surface expression, but unlike 18:1 lysoPtdCho did not lead to cyclooxygenase-2 protein expression. These data show that 18:0 lysoPtdCho-ClOH is elevated in atherosclerotic tissue and may have unique pro-atherogenic properties compared to lysoPtdCho.
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Abstract
Toxins that alter neurotransmitter release from nerve terminals are of considerable scientific and clinical importance. Many advances were recently made in the understanding of their molecular mechanisms of action and use in human therapy. Here, we focus on presynaptic neurotoxins, which are very potent inhibitors of the neurotransmitter release because they are endowed with specific enzymatic activities: (1) clostridial neurotoxins with a metallo-proteolytic activity and (2) snake presynaptic neurotoxins with a phospholipase A2 activity.
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Affiliation(s)
- Ornella Rossetto
- Departimento de Scienze Biomediche and Istituto CNR di Neuroscienze, Universita di Padova, Viale G. Colombo 3, 35121, Padova, Italy
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Rigoni M, Pizzo P, Schiavo G, Weston AE, Zatti G, Caccin P, Rossetto O, Pozzan T, Montecucco C. Calcium Influx and Mitochondrial Alterations at Synapses Exposed to Snake Neurotoxins or Their Phospholipid Hydrolysis Products. J Biol Chem 2007; 282:11238-45. [PMID: 17311918 DOI: 10.1074/jbc.m610176200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Snake presynaptic phospholipase A2 neurotoxins (SPANs) bind to the presynaptic membrane and hydrolyze phosphatidylcholine with generation of lysophosphatidylcholine (LysoPC) and fatty acid (FA). The LysoPC+FA mixture promotes membrane fusion, inducing the exocytosis of the ready-to-release synaptic vesicles. However, also the reserve pool of synaptic vesicles disappears from nerve terminals intoxicated with SPAN or LysoPC+FA. Here, we show that LysoPC+FA and SPANs cause a large influx of extracellular calcium into swollen nerve terminals, which accounts for the extensive synaptic vesicle release. This is paralleled by the change of morphology and the collapse of membrane potential of mitochondria within nerve bulges. These results complete the picture of events occurring at nerve terminals intoxicated by SPANs and define the LysoPC+FA lipid mixture as a novel and effective agonist of synaptic vesicle release.
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Affiliation(s)
- Michela Rigoni
- Department of Biomedical Sciences and Consiglio Nazionale Ricerche Institute of Neuroscience, University of Padova, 35121 Padova, Italy
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Yan S, Chai H, Wang H, Yang H, Nan B, Yao Q, Chen C. Effects of lysophosphatidylcholine on monolayer cell permeability of human coronary artery endothelial cells. Surgery 2005; 138:464-73. [PMID: 16213900 DOI: 10.1016/j.surg.2005.06.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 06/22/2005] [Accepted: 06/25/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND Lysophosphatidylcholine (LysoPC) is a product of phosphatidylcholine hydrolysis by phospholipase A2, which is associated with atherosclerosis. However, the underlying molecular mechanisms are still unclear. The purpose of this study was to determine the effects of LysoPC on monolayer permeability of human coronary artery endothelial cells (HCAECs). METHODS HCAECs were cultured with LysoPC in a dose- and time-dependent manner. Monolayer permeability was studied by using a transwell system with a Texas-Red-labeled dextran tracer. The messenger RNA and protein levels of endothelial tight junction proteins were determined with the use of real-time reverse transcriptase-polymerase chain reaction and Western blot analysis, respectively. Superoxide anion levels were determined with the use of fluorescent dye dihydroethidium-based flow cytometry analysis. Activation of mitogen-activated protein kinases was determined by performing Bio-Plex immunoassay. RESULTS LysoPC (30 micromol/L) increased monolayer permeability by 53% and decreased the messenger RNA levels of zonula occludens-1, occludin, claudin-1, and junctional adhesion molecule by 44%, 53%, 50%, and 52%, respectively, compared with controls (P < .05). Western blot analysis showed reduced protein levels of these tight junction molecules. LysoPC (15 and 30 micromol/L) also increased superoxide anion production by 54% and 58%, respectively, compared with controls (P < .05). Antioxidant seleno-L-methionine (20 and 30 micromol/L) inhibited LysoPC (30 micromol/L)-induced permeability by 42% and 68%, respectively (P < .05). Furthermore, LysoPC (30 micromol/L) activated c-Jun N-terminal kinase and p38 phosphorylation, but not extracellular signal-related kinase 1/2, within 5 to 10 minutes. CONCLUSIONS LysoPC increases monolayer permeability and reduces the expression of tight junction molecules in HCAECs through oxidative stress and activation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase. The antioxidant can effectively block LysoPC-induced endothelial permeability.
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Affiliation(s)
- Shaoyu Yan
- Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA
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Wilson-Ashworth HA, Judd AM, Law RM, Freestone BD, Taylor S, Mizukawa MK, Cromar KR, Sudweeks S, Bell JD. Formation of transient non-protein calcium pores by lysophospholipids in S49 Lymphoma cells. J Membr Biol 2005; 200:25-33. [PMID: 15386157 DOI: 10.1007/s00232-004-0691-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2004] [Revised: 05/12/2004] [Indexed: 10/26/2022]
Abstract
Palmitoyl-lysophosphatidylcholine promotes a transient calcium influx in lymphoma cells. Previously, it was observed that this influx was accompanied by a temporary increase in propidium iodide permeability that appeared linked to calcium entry. Those studies demonstrated that cobalt or nickel could block the response to lysophosphatidylcholine and raised the question of whether the calcium conductance involved specific channels. This communication describes a series of experiments to address that issue. The time dependence and structural specificity of the responses to lysophosphatidylcholine reinforced the hypothesis of a specific channel or transporter. Nevertheless, observations using patch clamp or calcium channel blockers suggested that this "channel" does not involve proteins. Alternative protein-mediated mechanisms such as indirect involvement of the sodium-calcium exchanger and the sodium-potassium ATPase were also excluded. Experiments with extracellular and intracellular calcium chelators suggested a common route of entry for calcium and propidium iodide. More directly, the ability of lysophosphatidylcholine to produce cobalt-sensitive permeability to propidium iodide was reproduced in protein-free artificial membranes. Finally, the transient nature of the calcium time course was rationalized quantitatively by the kinetics of lysophosphatidylcholine metabolism. These results suggest that physiological concentrations of lysophosphatidylcholine can directly produce membrane pores that mimic some of the properties of specific protein channels.
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Huang TY, Chen HI, Liu CY, Jen CJ. Lysophosphatidylcholine alters vascular tone in rat aorta by suppressing endothelial [Ca(2+)](I) signaling. J Biomed Sci 2002; 9:327-33. [PMID: 12145530 DOI: 10.1007/bf02256588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The detailed mechanism of how lysophosphatidylcholine (LPC) suppresses endothelium-dependent vasodilatation is unclear at present. We investigated the effects of LPC on endothelial intracellular calcium (EC [Ca(2+)](i)) signaling and vascular tone simultaneously using a new technique we developed. Fura-2-labeled rat aortic specimens were mounted in a tissue flow chamber and precontracted with phenylephrine (5 x 10(-8) M). Under either basal or agonist-stimulated conditions, the EC [Ca(2+)](i) level was calculated from fura 2 fluorescence ratio images, and the vascular tone was estimated by measuring the relative displacement of the fluorescence images. Although both acetylcholine (ACh)-induced EC [Ca(2+)](i) elevation and the concomitant vasorelaxation were partially suppressed in specimens pretreated with LPC (20 microM), the quantitative relationship between EC [Ca(2+)](i) elevation and the corresponding vasorelaxation was unaffected. A high concentration of LPC (40 microM) completely eliminated ACh-evoked [Ca(2+)](i) elevation and vasodilatation. It has been reported that exposing vascular tissue to a calcium-free buffer causes a reduction in the EC [Ca(2+)](i) level and the accompanying vasoconstriction. Pretreatment with 20 microM LPC reduced the basal EC [Ca(2+)](i) level and abolished the calcium-free solution-induced EC [Ca(2+)](i) reduction and vasoconstriction. We conclude that LPC impairs endothelium-dependent vasorelaxation mainly by reducing the basal EC [Ca(2+)](i) level and suppressing agonist-evoked EC [Ca(2+)](i) signaling.
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Affiliation(s)
- Tung-Yi Huang
- Department of Physiology and Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
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Kwan CY, Harrison PH, Duspara PA, Daniel EE. Vasorelaxant effects of pramanicin, an anti-fungal agent: selective action on endothelial cells. JAPANESE JOURNAL OF PHARMACOLOGY 2001; 85:234-40. [PMID: 11325015 DOI: 10.1254/jjp.85.234] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A newly discovered antifungal agent, pramanicin, within the therapeutically effective concentration range (4-100 microM), inhibits the tone of phenylephrine (PE)-precontracted dog carotid arterial rings in a concentration-dependent manner and leads to gradual development of relaxation. However, pramanicin had no effect on rings precontracted with 100 mM KCl or on endothelium-denuded rings. Thus, inhibition by pramanicin of PE-induced contraction was endothelium-dependent. Preincubation of 100 microM pramanicin with carotid arterial rings for 30 min did not significantly affect the concentration-contraction response to PE, but almost completely inhibited the endothelium-dependent relaxation response to subsequent addition of 3 microM carbachol or 100 microM pramanicin. This irreversible inhibition of endothelium-dependent relaxation, which is independent of extracellular Ca2+, suggests possible endothelial cell damage by pramanicin. Pretreatment of the endothelium-intact vascular rings with L-N(G)-nitro-arginine (100 microM) inhibited the relaxation of PE-precontracted rings induced by 3 microM carbachol or 100 microM pramanicin, suggesting that the generation of nitric oxide (NO) in endothelial cells mediates the slow vascular relaxation induced by pramanicin. We conclude that pramanicin has little direct effect on the contractility of smooth muscle cells, but causes an initial slow endothelium-dependent, NO-mediated vascular relaxation. This is followed by a cytotoxic effect on vascular endothelial cells, eventually resulting in the loss of vasorelaxant function.
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Affiliation(s)
- C Y Kwan
- Department of Medicine, Faculty of Health Sciences, Faculty of Science, McMaster University, Hamilton, Ontario, Canada.
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