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Klose AM, Klier M, Gorressen S, Elvers M. Enhanced Integrin Activation of PLD2-Deficient Platelets Accelerates Inflammation after Myocardial Infarction. Int J Mol Sci 2020; 21:ijms21093210. [PMID: 32370031 PMCID: PMC7247352 DOI: 10.3390/ijms21093210] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/20/2022] Open
Abstract
Background: Phospholipase (PL)D1 is crucial for integrin αIIbβ3 activation of platelets in arterial thrombosis and TNF-α-mediated inflammation and TGF-β-mediated collagen scar formation after myocardial infarction (MI) in mice. Enzymatic activity of PLD is not responsible for PLD-mediated TNF-α signaling and myocardial healing. The impact of PLD2 in ischemia reperfusion injury is unknown. Methods: PLD2-deficient mice underwent myocardial ischemia and reperfusion (I/R). Results: Enhanced integrin αIIbβ3 activation of platelets resulted in elevated interleukin (IL)-6 release from endothelial cells in vitro and enhanced IL-6 plasma levels after MI in PLD2-deficient mice. This was accompanied by enhanced migration of inflammatory cells into the infarct border zone and reduced TGF-β plasma levels after 72 h that might account for enhanced inflammation in PLD2-deficient mice. In contrast to PLD1, TNF-α signaling, infarct size and cardiac function 24 h after I/R were not altered when PLD2 was deleted. Furthermore, TGF-β plasma levels, scar formation and heart function were comparable between PLD2-deficient and control mice 21 days post MI. Conclusions: The present study contributes to our understanding about the role of PLD isoforms and altered platelet signaling in the process of myocardial I/R injury.
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Affiliation(s)
- Aglaia Maria Klose
- Department of Vascular and Endovascular Surgery, Experimental Vascular Medicine, Heinrich-Heine University Medical Center, 40225 Düsseldorf, Germany; (A.M.K.); (M.K.)
| | - Meike Klier
- Department of Vascular and Endovascular Surgery, Experimental Vascular Medicine, Heinrich-Heine University Medical Center, 40225 Düsseldorf, Germany; (A.M.K.); (M.K.)
| | - Simone Gorressen
- Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine University, 40225 Düsseldorf, Germany;
| | - Margitta Elvers
- Department of Vascular and Endovascular Surgery, Experimental Vascular Medicine, Heinrich-Heine University Medical Center, 40225 Düsseldorf, Germany; (A.M.K.); (M.K.)
- Correspondence:
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Lu WJ, Chung CL, Chen RJ, Huang LT, Lien LM, Chang CC, Lin KH, Sheu JR. An Antithrombotic Strategy by Targeting Phospholipase D in Human Platelets. J Clin Med 2018; 7:jcm7110440. [PMID: 30441821 PMCID: PMC6262437 DOI: 10.3390/jcm7110440] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/06/2018] [Accepted: 11/13/2018] [Indexed: 01/16/2023] Open
Abstract
Phospholipase D (PLD) is involved in many biological processes. PLD1 plays a crucial role in regulating the platelet activity of mice; however, the role of PLD in the platelet activation of humans remains unclear. Therefore, we investigated whether PLD is involved in the platelet activation of humans. Our data revealed that inhibition of PLD1 or PLD2 using pharmacological inhibitors effectively inhibits platelet aggregation in humans. However, previous studies have showed that PLD1 or PLD2 deletion did not affect mouse platelet aggregation in vitro, whereas only PLD1 deletion inhibited thrombus formation in vivo. Intriguingly, our data also showed that the pharmacological inhibition of PLD1 or PLD2 does not affect mouse platelet aggregation in vitro, whereas the inhibition of only PLD1 delayed thrombus formation in vivo. These findings indicate that PLD may play differential roles in humans and mice. In humans, PLD inhibition attenuates platelet activation, adhesion, spreading, and clot retraction. For the first time, we demonstrated that PLD1 and PLD2 are essential for platelet activation in humans, and PLD plays different roles in platelet function in humans and mice. Our findings also indicate that targeting PLD may provide a safe and alternative therapeutic approach for preventing thromboembolic disorders.
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Affiliation(s)
- Wan Jung Lu
- Department of Medical Research, Taipei Medical University Hospital, Taipei 110, Taiwan.
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
- Graduate Institute of Metabolism and Obesity Sciences, College of Public Health and Nutrition, Taipei Medical University, Taipei 110, Taiwan.
| | - Chi Li Chung
- Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan.
- School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
| | - Ray Jade Chen
- Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei 110, Taiwan.
- School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
| | - Li Ting Huang
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
| | - Li Ming Lien
- School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
- Department of Neurology, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan.
| | - Chao Chien Chang
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
| | - Kuan Hung Lin
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
- Central Laboratory, Shin-Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan.
- Institute of Biomedical Sciences, Mackay Medical College, New Taipei City 252, Taiwan.
| | - Joen Rong Sheu
- Department of Pharmacology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
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3
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Identification of key lipids critical for platelet activation by comprehensive analysis of the platelet lipidome. Blood 2018; 132:e1-e12. [PMID: 29784642 DOI: 10.1182/blood-2017-12-822890] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/12/2018] [Indexed: 12/23/2022] Open
Abstract
Platelet integrity and function critically depend on lipid composition. However, the lipid inventory in platelets was hitherto not quantified. Here, we examined the lipidome of murine platelets using lipid-category tailored protocols on a quantitative lipidomics platform. We could show that the platelet lipidome comprises almost 400 lipid species and covers a concentration range of 7 orders of magnitude. A systematic comparison of the lipidomics network in resting and activated murine platelets, validated in human platelets, revealed that <20% of the platelet lipidome is changed upon activation, involving mainly lipids containing arachidonic acid. Sphingomyelin phosphodiesterase-1 (Smpd1) deficiency resulted in a very specific modulation of the platelet lipidome with an order of magnitude upregulation of lysosphingomyelin (SPC), and subsequent modification of platelet activation and thrombus formation. In conclusion, this first comprehensive quantitative lipidomic analysis of platelets sheds light on novel mechanisms important for platelet function, and has therefore the potential to open novel diagnostic and therapeutic opportunities.
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Geue S, Walker-Allgaier B, Eißler D, Tegtmeyer R, Schaub M, Lang F, Gawaz M, Borst O, Münzer P. Doxepin inhibits GPVI-dependent platelet Ca 2+ signaling and collagen-dependent thrombus formation. Am J Physiol Cell Physiol 2017; 312:C765-C774. [PMID: 28404545 DOI: 10.1152/ajpcell.00262.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 04/11/2017] [Accepted: 04/11/2017] [Indexed: 12/24/2022]
Abstract
Platelet adhesion, activation, and aggregation are essential for primary hemostasis, but are also critically involved in the development of acute arterial thrombotic occlusion. Stimulation of the collagen receptor glycoprotein VI (GPVI) leads to phospholipase Cγ2-dependent inositol triphosphate (IP3) production with subsequent platelet activation, due to increased intracellular Ca2+ concentration ([Ca2+]i). Although tricyclic antidepressants have been shown to potentially impair platelet activation, nothing is hitherto known about potential effects of the tricyclic antidepressant doxepin on platelet Ca2+ signaling and thrombus formation. As shown in the present study, doxepin significantly diminished the stimulatory effect of GPVI agonist collagen-related peptide (CRP) on intracellular Ca2+ release as well as subsequent extracellular Ca2+ influx. Doxepin was partially effective by impairment of CRP-dependent IP3 production. Moreover, doxepin abrogated CRP-induced platelet degranulation and integrin αIIbβ3 activation and aggregation. Finally, doxepin markedly blunted in vitro platelet adhesion to collagen and thrombus formation under high arterial shear rates (1,700-s). In conclusion, doxepin is a powerful inhibitor of GPVI-dependent platelet Ca2+ signaling, platelet activation, and thrombus formation.
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Affiliation(s)
- Sascha Geue
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Britta Walker-Allgaier
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Daniela Eißler
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Roland Tegtmeyer
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Malte Schaub
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Florian Lang
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and.,Department of Physiology, University of Tuebingen, Tuebingen, Germany
| | - Meinrad Gawaz
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Oliver Borst
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
| | - Patrick Münzer
- Department of Cardiology and Cardiovascular Medicine, University of Tuebingen, Tuebingen, Germany; and
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5
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PLD1 participates in BDNF-induced signalling in cortical neurons. Sci Rep 2015; 5:14778. [PMID: 26437780 PMCID: PMC4594037 DOI: 10.1038/srep14778] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/09/2015] [Indexed: 01/07/2023] Open
Abstract
The brain-derived neurotrophic factor BDNF plays a critical role in neuronal development and the induction of L-LTP at glutamatergic synapses in several brain regions. However, the cellular and molecular mechanisms underlying these BDNF effects have not been firmly established. Using in vitro cultures of cortical neurons from knockout mice for Pld1 and Rsk2, BDNF was observed to induce a rapid RSK2-dependent activation of PLD and to stimulate BDNF ERK1/2-CREB and mTor-S6K signalling pathways, but these effects were greatly reduced in Pld1(-/-) neurons. Furthermore, phospho-CREB did not accumulate in the nucleus, whereas overexpression of PLD1 amplified the BDNF-dependent nuclear recruitment of phospho-ERK1/2 and phospho-CREB. This BDNF retrograde signalling was prevented in cells silenced for the scaffolding protein PEA15, a protein which complexes with PLD1, ERK1/2, and RSK2 after BDNF treatment. Finally PLD1, ERK1/2, and RSK2 partially colocalized on endosomal structures, suggesting that these proteins are part of the molecular module responsible for BDNF signalling in cortical neurons.
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6
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Lucke-Wold BP, Turner RC, Logsdon AF, Simpkins JW, Alkon DL, Smith KE, Chen YW, Tan Z, Huber JD, Rosen CL. Common mechanisms of Alzheimer's disease and ischemic stroke: the role of protein kinase C in the progression of age-related neurodegeneration. J Alzheimers Dis 2015; 43:711-24. [PMID: 25114088 PMCID: PMC4446718 DOI: 10.3233/jad-141422] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ischemic stroke and Alzheimer's disease (AD), despite being distinct disease entities, share numerous pathophysiological mechanisms such as those mediated by inflammation, immune exhaustion, and neurovascular unit compromise. An important shared mechanistic link is acute and chronic changes in protein kinase C (PKC) activity. PKC isoforms have widespread functions important for memory, blood-brain barrier maintenance, and injury repair that change as the body ages. Disease states accelerate PKC functional modifications. Mutated forms of PKC can contribute to neurodegeneration and cognitive decline. In some cases the PKC isoforms are still functional but are not successfully translocated to appropriate locations within the cell. The deficits in proper PKC translocation worsen stroke outcome and amyloid-β toxicity. Cross talk between the innate immune system and PKC pathways contribute to the vascular status within the aging brain. Unfortunately, comorbidities such as diabetes, obesity, and hypertension disrupt normal communication between the two systems. The focus of this review is to highlight what is known about PKC function, how isoforms of PKC change with age, and what additional alterations are consequences of stroke and AD. The goal is to highlight future therapeutic targets that can be applied to both the treatment and prevention of neurologic disease. Although the pathology of ischemic stroke and AD are different, the similarity in PKC responses warrants further investigation, especially as PKC-dependent events may serve as an important connection linking age-related brain injury.
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Affiliation(s)
- Brandon P. Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Ryan C. Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Aric F. Logsdon
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - James W. Simpkins
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Daniel L. Alkon
- Blanchette Rockefeller Neurosciences Institute, Morgantown, WV, USA
| | - Kelly E. Smith
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Yi-Wen Chen
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Zhenjun Tan
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Jason D. Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV, USA
| | - Charles L. Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV, USA
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV, USA
- Correspondence to: Charles L. Rosen, MD, PhD, Department of Neurosurgery, West Virginia University School of Medicine, One Medical Center Drive, Suite 4300, Health Sciences Center, PO Box 9183, Morgantown, WV 26506-9183, USA. Tel.: +1 304 293 5041; Fax: +1 304 293 4819;
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7
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Pivotal role of phospholipase D1 in tumor necrosis factor-α-mediated inflammation and scar formation after myocardial ischemia and reperfusion in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2450-64. [PMID: 25046692 DOI: 10.1016/j.ajpath.2014.06.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 05/28/2014] [Accepted: 06/04/2014] [Indexed: 01/07/2023]
Abstract
Myocardial inflammation is critical for ventricular remodeling after ischemia. Phospholipid mediators play an important role in inflammatory processes. In the plasma membrane they are degraded by phospholipase D1 (PLD1). PLD1 was shown to be critically involved in ischemic cardiovascular events. Moreover, PLD1 is coupled to tumor necrosis factor-α signaling and inflammatory processes. However, the impact of PLD1 in inflammatory cardiovascular disease remains elusive. Here, we analyzed the impact of PLD1 in tumor necrosis factor-α-mediated activation of monocytes after myocardial ischemia and reperfusion using a mouse model of myocardial infarction. PLD1 expression was highly up-regulated in the myocardium after ischemia/reperfusion. Genetic ablation of PLD1 led to defective cell adhesion and migration of inflammatory cells into the infarct border zone 24 hours after ischemia/reperfusion injury, likely owing to reduced tumor necrosis factor-α expression and release, followed by impaired nuclear factor-κB activation and interleukin-1 release. Moreover, PLD1 was found to be important for transforming growth factor-β secretion and smooth muscle α-actin expression of cardiac fibroblasts because myofibroblast differentiation and interstitial collagen deposition were altered in Pld1(-/-) mice. Consequently, infarct size was increased and left ventricular function was impaired 28 days after myocardial infarction in Pld1(-/-) mice. Our results indicate that PLD1 is crucial for tumor necrosis factor-α-mediated inflammation and transforming growth factor-β-mediated collagen scar formation, thereby augmenting cardiac left ventricular function after ischemia/reperfusion.
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8
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Pre-activated blood platelets and a pro-thrombotic phenotype in APP23 mice modeling Alzheimer's disease. Cell Signal 2014; 26:2040-50. [PMID: 24928203 DOI: 10.1016/j.cellsig.2014.05.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 05/26/2014] [Indexed: 11/21/2022]
Abstract
Platelet activation and thrombus formation play a critical role in primary hemostasis but also represent a pathophysiological mechanism leading to acute thrombotic vascular occlusions. Besides, platelets modulate cellular processes including inflammation, angiogenesis and neurodegeneration. On the other hand, platelet activation and thrombus formation are altered in different diseases leading to either bleeding complications or pathological thrombus formation. For many years platelets have been considered to play a role in neuroinflammatory diseases such as Alzheimer's disease (AD). AD is characterized by deposits of amyloid-β (Aβ) and strongly related to vascular diseases with platelets playing a critical role in the progression of AD because exposure of platelets to Aβ induces platelet activation, platelet Aβ release, and enhanced platelet adhesion to collagen in vitro and at the injured carotid artery in vivo. However, the molecular mechanisms and the relation between vascular pathology and amyloid-β plaque formation in the pathogenesis of AD are not fully understood. Compelling evidence is suggestive for altered platelet activity in AD patients. Thus we analyzed platelet activation and thrombus formation in aged AD transgenic mice (APP23) known to develop amyloid-β deposits in the brain parenchyma and cerebral vessels. As a result, platelets are in a pre-activated state in blood of APP23 mice and showed strongly enhanced integrin activation, degranulation and spreading kinetics on fibrinogen surfaces upon stimulation. This enhanced platelet signaling translated into almost unlimited thrombus formation on collagen under flow conditions in vitro and accelerated vessel occlusion in vivo suggesting that these mice are at high risk of arterial thrombosis leading to cerebrovascular and unexpectedly to cardiovascular complications that might be also relevant in AD patients.
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Fälker K, Klarström-Engström K, Bengtsson T, Lindahl TL, Grenegård M. The Toll-like receptor 2/1 (TLR2/1) complex initiates human platelet activation via the src/Syk/LAT/PLCγ2 signalling cascade. Cell Signal 2014; 26:279-86. [DOI: 10.1016/j.cellsig.2013.11.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 11/06/2013] [Indexed: 11/16/2022]
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10
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Scott SA, Mathews TP, Ivanova PT, Lindsley CW, Brown HA. Chemical modulation of glycerolipid signaling and metabolic pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1060-84. [PMID: 24440821 DOI: 10.1016/j.bbalip.2014.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 01/04/2023]
Abstract
Thirty years ago, glycerolipids captured the attention of biochemical researchers as novel cellular signaling entities. We now recognize that these biomolecules occupy signaling nodes critical to a number of physiological and pathological processes. Thus, glycerolipid-metabolizing enzymes present attractive targets for new therapies. A number of fields-ranging from neuroscience and cancer to diabetes and obesity-have elucidated the signaling properties of glycerolipids. The biochemical literature teems with newly emerging small molecule inhibitors capable of manipulating glycerolipid metabolism and signaling. This ever-expanding pool of chemical modulators appears daunting to those interested in exploiting glycerolipid-signaling pathways in their model system of choice. This review distills the current body of literature surrounding glycerolipid metabolism into a more approachable format, facilitating the application of small molecule inhibitors to novel systems. This article is part of a Special Issue entitled Tools to study lipid functions.
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Affiliation(s)
- Sarah A Scott
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Thomas P Mathews
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Pavlina T Ivanova
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - H Alex Brown
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA.
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Jackson ECG, Ortar G, McNicol A. The Effects of an Inhibitor of Diglyceride Lipase on Collagen-Induced Platelet Activation. J Pharmacol Exp Ther 2013; 347:582-8. [DOI: 10.1124/jpet.113.205591] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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12
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Thielmann I, Stegner D, Kraft P, Hagedorn I, Krohne G, Kleinschnitz C, Stoll G, Nieswandt B. Redundant functions of phospholipases D1 and D2 in platelet α-granule release. J Thromb Haemost 2012; 10:2361-72. [PMID: 22974101 DOI: 10.1111/j.1538-7836.2012.04924.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Platelet activation and aggregation are crucial for primary hemostasis, but can also result in occlusive thrombus formation. Agonist-induced platelet activation involves different signaling pathways leading to the activation of phospholipases, which produce second messengers. The role of phospholipase C (PLC) in platelet activation is well established, but less is known about the relevance of phospholipase D (PLD). OBJECTIVE AND METHODS The aim of this study was to determine a potential function of PLD2 in platelet physiology. Thus, we investigated the function of PLD2 in platelet signaling and thrombus formation, by generating mice lacking PLD2 or both PLD1 and PLD2. Adhesion, activation and aggregation of PLD-deficient platelets were analyzed in vitro and in vivo. RESULTS Whereas the absence of PLD2 resulted in reduced PLD activity in platelets, it had no detectable effect on the function of the cells in vitro and in vivo. However, the combined deficiency of both PLD isoforms resulted in defective α-granule release and protection in a model of FeCl3 -induced arteriolar thrombosis, effects that were not observed in mice lacking only one PLD isoform. CONCLUSION These results reveal redundant roles of PLD1 and PLD2 in platelet α-granule secretion, and indicate that this may be relevant for pathologic thrombus formation.
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Affiliation(s)
- I Thielmann
- Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, University of Würzburg, Würzburg Department of Neurology, University of Würzburg, Würzburg Biocenter, University of Würzburg, Würzburg, Germany
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