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de Bejczy A. Phosphatidylethanol (B-PEth) and other direct and indirect biomarkers of alcohol consumption. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 175:313-344. [PMID: 38555120 DOI: 10.1016/bs.irn.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
When identifying, preventing and treating alcohol use disorder, a correct estimation of alcohol intake is essential. An objective marker is preferred as self-reported alcohol intake suffers from bias, and the use of alcohol biomarkers is increasing globally. An easy-to-use blood biomarker to correctly assess alcohol consumption is an invaluable asset in alcohol treatment strategies, as well as in alcohol research studies. The specific, cumulative, biomarker phosphatidylethanol, mirroring the past two weeks of consumption, has shown superiority over traditional biomarkers and is an attractive choice of proxy for alcohol intake.
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Affiliation(s)
- Andrea de Bejczy
- Addiction Biology Unit, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Addiction and Dependency, Sahlgrenska University Hospital, Gothenburg, Sweden.
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2
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Botten N, Hodges RR, Bair J, Utheim TP, Serhan CN, Yang M, Dartt DA. Resolvin D2 uses multiple Ca 2+ -dependent signaling pathways to stimulate mucin secretion in rat and human conjunctival goblet cells. J Cell Physiol 2022; 237:3816-3833. [PMID: 36066128 PMCID: PMC9560994 DOI: 10.1002/jcp.30854] [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: 11/30/2021] [Revised: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 11/11/2022]
Abstract
The mucin layer of the tear film is produced by goblet cells in the conjunctiva to protect the ocular surface and maintain homeostasis. The pro-resolving lipid mediator resolvin D2 (RvD2) biosynthesized from an omega 3 fatty acid actively terminates inflammation and regulates mucin secretion from conjunctival goblet cells. Our objective was to determine which Ca2+ -dependent signaling pathways RvD2 uses to stimulate conjunctival goblet cell function (CGC). We hypothesize that RvD2 activates multiple intracellular Ca2+ signaling pathways to stimulate CGC secretion. Rat and human CGCs were cultured from conjunctival explants. The amount of RvD2 receptor GPR18/DRV2 message and protein were determined. The intracellular concentration of Ca2+ ([Ca2+ ]i ) was measured in CGCs using a fluorescent Ca2+ dye and mucin secretion was determined by measuring protein secretion enzymatically with a lectin. Goblet cells were incubated with signaling pathway inhibitors before stimulation with RvD2 and [Ca2+ ]i or secretion was measured. In rat and human CGCs RvD2 receptor and in rat CGCs IP3 (a molecule that releases Ca2+ from intracellular organelles) receptors 1-3 were detected. In both species of CGC RvD2 increased [Ca2+ ]i similarly to RvD1. In rat CGCs, the increase in [Ca2+ ]i and secretion stimulated by RvD2 was significantly blocked by inhibitors to phospholipase (PL-) C and IP3 -receptor, but not protein kinase C. Increase in [Ca2+ ]i was blocked by the PLD inhibitor, but not the PLA2 inhibitor. Secretion was blocked by PLA2 inhibitor, but not the PLD inhibitor. An inhibitor of the epidermal growth factor receptor blocked the increase in [Ca2+ ]i by RvD2 in both species of CGCs. In CGCs RvD2 activates multiple intracellular signaling pathways that are Ca2+ -dependent, along with one Ca2+ -independent and one cAMP/protein kinase A-dependent pathway. Activation of these pathways stimulate mucin secretion from rat and human CGCs into the tear film contributing to ocular surface homeostasis and health.
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Affiliation(s)
- Nora Botten
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Robin R. Hodges
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey Bair
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Tor P. Utheim
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Charles N. Serhan
- Center for Experimental Therapeutics and Reperfusion Injury, Harvard Medical School, Boston, Massachusetts, USA
- Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Menglu Yang
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Darlene A. Dartt
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
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Tsai HJ, Cheng JC, Kao ML, Chiu HP, Chiang YH, Chen DP, Rau KM, Liao HR, Tseng CP. Integrin αIIbβ3 outside-in signaling activates human platelets through serine 24 phosphorylation of Disabled-2. Cell Biosci 2021; 11:32. [PMID: 33557943 PMCID: PMC7869483 DOI: 10.1186/s13578-021-00532-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/05/2021] [Indexed: 11/29/2022] Open
Abstract
Background Bidirectional integrin αIIbβ3 signaling is essential for platelet activation. The platelet adaptor protein Disabled-2 (Dab2) is a key regulator of integrin signaling and is phosphorylated at serine 24 in eukaryotic cells. However, the mechanistic insight and function of Dab2-serine 24 phosphorylation (Dab2-pSer24) in platelet biology are barely understood. This study aimed to define whether and how Dab2 is phosphorylated at Ser24 during platelet activation and to investigate the effect of Dab2-pSer24 on platelet function. Results An antibody with confirmed specificity for Dab2-pSer24 was generated. By using this antibody as a tool, we showed that protein kinase C (PKC)-mediated Dab2-pSer24 was a conservative signaling event when human platelets were activated by the platelet agonists such as thrombin, collagen, ADP, 12-O-tetradecanoylphorbol-13-acetate, and the thromboxane A2 activator U46619. The agonists-stimulated Dab2-pSer24 was attenuated by pretreatment of platelets with the RGDS peptide which inhibits integrin outside-in signaling by competitive binding of integrin αIIb with fibrinogen. Direct activation of platelet integrin outside-in signaling by combined treatment of platelets with manganese dichloride and fibrinogen or by spreading of platelets on fibrinogen also resulted in Dab2-pSer24. These findings implicate that Dab2-pSer24 was associated with the outside-in signaling of integrin. Further analysis revealed that Dab2-pSer24 was downstream of Src-PKC-axis and phospholipase D1 underlying the integrin αIIbβ3 outside-in signaling. A membrane penetrating peptide R11-Ser24 which contained 11 repeats of arginine linked to the Dab2-Ser24 phosphorylation site and its flanking sequences (RRRRRRRRRRR19APKAPSKKEKK29) and the R11-S24A peptide with Ser24Ala mutation were designed to elucidate the functions of Dab2-pSer24. R11-Ser24 but not R11-S24A inhibited agonists-stimulated Dab2-pSer24 and consequently suppressed platelet spreading on fibrinogen, with no effect on platelet aggregation and fibrinogen binding. Notably, Ser24 and the previously reported Ser723 phosphorylation (Dab2-pSer723) occurred exclusively in a single Dab2 molecule and resulted in distinctive subcellular distribution and function of Dab2. Dab2-pSer723 was mainly distributed in the cytosol of activated platelets and associated with integrin inside-out signaling, while Dab2-pSer24 was mainly distributed in the membrane fraction of activated platelets and associated with integrin outside-in signaling. Conclusions These findings demonstrate for the first time that Dab2-pSer24 is conservative in integrin αIIbβ3 outside-in signaling during platelet activation and plays a novel role in the control of cytoskeleton reorganization and platelet spreading on fibrinogen.
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Affiliation(s)
- Hui-Ju Tsai
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China
| | - Ju-Chien Cheng
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, 404, Taiwan, Republic of China
| | - Man-Leng Kao
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China
| | - Hung-Pin Chiu
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China
| | - Yi-Hsuan Chiang
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China
| | - Ding-Ping Chen
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China.,Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, 333, Taiwan, Republic of China
| | - Kun-Ming Rau
- Department of Hematology-Oncology, E-Da Cancer Hospital, Kaohsiung, 824, Taiwan, Republic of China.,School of Medicine, College of Medicine, I-Shou University, Kaohsiung, 824, Taiwan, Republic of China
| | - Hsiang-Ruei Liao
- Graduate institute of Natural Products, College of Medicine, Chang-Gung University, Taoyuan, 333, Taiwan, Republic of China.,Graduate institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China.,Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, 333, Taiwan, Republic of China
| | - Ching-Ping Tseng
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China. .,Department of Laboratory Medicine, Chang Gung Memorial Hospital, Taoyuan, 333, Taiwan, Republic of China. .,Graduate institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China. .,Molecular Medicine Research Center, Chang Gung University, Taoyuan, 333, Taiwan, Republic of China.
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Yücel G, Behnes M, Barth C, Wenke A, Sartorius B, Mashayekhi K, Yazdani B, Bertsch T, Rusnak J, Saleh A, Hoffmann U, Fastner C, Lang S, Zhou X, Sattler K, Borggrefe M, Akin I. Percutaneous Closure of Left Atrial Appendage significantly affects Lipidome Metabolism. Sci Rep 2018; 8:5894. [PMID: 29650978 PMCID: PMC5897373 DOI: 10.1038/s41598-018-23935-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 03/23/2018] [Indexed: 11/09/2022] Open
Abstract
Patients with non-valvular atrial fibrillation (AF) and a high risk for oral anticoagulation can be treated by percutaneous implantation of left atrial appendage occlusion devices (LAAC) to reduce the risk of cardio-embolic stroke. This study evaluates whether LAAC may influence lipid metabolism, which has never been investigated before. Patients with successful LAAC were included consecutively. Venous peripheral blood samples of patients were collected immediately before (T0, baseline) and 6 months after (T1, mid-term) LAAC. A targeted metabolomics approach based on electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and MS/MS measurements was performed. A total of 34 lipids revealed a significant change from baseline to mid-term follow-up after successful LAAC. Subgroup analysis revealed confounding influence by gender, age, diabetes mellitus type II, body mass index, left ventricular ejection fraction, creatinine and NT-proBNP. After multivariable adjustment within logistic regression models, these 34 lipids were still significantly altered after LAAC. Successful percutaneous LAAC may affect lipid metabolism and thereby may potentially affect pro-atherogenic and cardio-toxic effects.
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Affiliation(s)
- G Yücel
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - M Behnes
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.
| | - C Barth
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - A Wenke
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - B Sartorius
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - K Mashayekhi
- Clinic for Cardiology and Angiology II, Universitäts-Herzzentrum Freiburg - Bad Krozingen, Bad Krozingen, Germany
| | - B Yazdani
- Fifth Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - T Bertsch
- Institute of Clinical Chemistry, Laboratory Medicine and Transfusion Medicine, General Hospital Nuremberg and Paracelsus Medical University, Nuremberg, Germany
| | - J Rusnak
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - A Saleh
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - U Hoffmann
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - C Fastner
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - S Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - X Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - K Sattler
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany
| | - M Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
| | - I Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, Mannheim, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, Mannheim, Germany
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5
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Chen W, Thielmann I, Gupta S, Subramanian H, Stegner D, van Kruchten R, Dietrich A, Gambaryan S, Heemskerk JWM, Hermanns HM, Nieswandt B, Braun A. Orai1-induced store-operated Ca(2+) entry enhances phospholipase activity and modulates canonical transient receptor potential channel 6 function in murine platelets. J Thromb Haemost 2014; 12:528-39. [PMID: 24520961 DOI: 10.1111/jth.12525] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/16/2014] [Indexed: 08/31/2023]
Abstract
BACKGROUND Orai1, the major store-operated Ca(2+) entry (SOCE) channel in platelets, is not only critical for enhancing diverse signaling pathways, but may also regulate receptor-operated Ca(2+) entry (ROCE). Dynamic coupling of the Orai1 signalosome to canonical transient receptor potential channels (TRPCs) has been suggested as an essential step in the activation of SOCE and ROCE. However, the functional significance of the biochemical interaction between Orai and TRPC isoforms remains controversial. OBJECTIVE We aimed to elucidate the role of Orai1 in diacylglycerol (DAG)-mediated ROCE. METHODS Trpc6(-/-) , Orai1(-/-) and Orai1(-/-) /Trpc6(-/-) mice were generated, and their platelets were analyzed. RESULTS Thapsigargin (TG)-induced SOCE was further reduced in Orai1(-/-) /Trpc6(-/-) platelets as compared with Orai1(-/-) platelets, thus revealing that TG-induced signaling pathways can activate TRPC6. Thapsigargin-induced SOCE leads to enhanced phospholipase C and D activity in wild-type platelets. The activity of both enzymes was significantly reduced in Orai1(-/-) platelets upon TG stimulation, whereas receptor-induced phospholipase activity was not affected. Furthermore, TG-induced and glycoprotein VI-mediated thromboxane A2 release was strongly dependent on Orai1-mediated SOCE. CONCLUSION The regulation of TRPC6 activity can occur independently of the physical interaction with Orai1. TRPC6 operates in crosstalk with Orai1 through Orai1-induced DAG production via phospholipase activation. Orai1-induced DAG production and thromboxane release amplify the second phase of Ca(2+) signaling in platelets.
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Affiliation(s)
- W Chen
- University Hospital and Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
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Phospholipase D is involved in the formation of Golgi associated clathrin coated vesicles in human parotid duct cells. PLoS One 2014; 9:e91868. [PMID: 24618697 PMCID: PMC3950291 DOI: 10.1371/journal.pone.0091868] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 02/17/2014] [Indexed: 11/19/2022] Open
Abstract
Phospholipase D (PLD) has been implicated in many cellular functions, such as vesicle trafficking, exocytosis, differentiation, and proliferation. The aim of this study was to characterize the role of PLD in HSY cells, a human cell line originating from the intercalated duct of the parotid gland. As the function and intracellular localization of PLD varies according to cell type, initially, the intracellular localization of PLD1 and PLD2 was determined. By immunofluorescence, PLD1 and PLD2 both showed a punctate cytoplasmic distribution with extensive co-localization with TGN-46. PLD1 was also found in the nucleus, while PLD2 was associated with the plasma membrane. Treatment of cells with the primary alcohol 1-butanol inhibits the hydrolysis of phosphatidylcoline by PLD thereby suppressing phosphatidic acid (PA) production. In untreated HSY cells, there was only a slight co-localization of PLD with the clathrin coated vesicles. When HSY cells were incubated with 1-butanol the total number of clathrin coated vesicles increased, especially in the juxtanuclear region and the co-localization of PLD with the clathrin coated vesicles was augmented. Transmission electron microscopy confirmed that the number of Golgi-associated coated vesicles was greater. Treatment with 1-butanol also affected the Golgi apparatus, increasing the volume of the Golgi saccules. The decrease in PA levels after treatment with 1-butanol likewise resulted in an accumulation of enlarged lysosomes in the perinuclear region. Therefore, in HSY cells PLD appears to be involved in the formation of Golgi associated clathrin coated vesicles as well as in the structural maintenance of the Golgi apparatus.
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7
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Wegener JW, Loga F, Stegner D, Nieswandt B, Hofmann F. Phospholipase D1 is involved in α‐adrenergic contraction of murine vascular smooth muscle. FASEB J 2014; 28:1044-8. [DOI: 10.1096/fj.13-237925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jörg W. Wegener
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
| | - Florian Loga
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
| | - David Stegner
- Lehrstuhl für Experimentelle BiomedizinUniversitätsklinikum Würzburg and Rudolf‐Virchow‐ZentrumDeutsche Forschungsgemeinschaft (DFG) Forschungszentrum für Experimentelle BiomedizinUniversität WürzburgWürzburgGermany
| | - Bernhard Nieswandt
- Lehrstuhl für Experimentelle BiomedizinUniversitätsklinikum Würzburg and Rudolf‐Virchow‐ZentrumDeutsche Forschungsgemeinschaft (DFG) Forschungszentrum für Experimentelle BiomedizinUniversität WürzburgWürzburgGermany
| | - Franz Hofmann
- For 923, Institut für Pharmakologie and Toxikologie, Technische Universität MünchenMünchenGermany
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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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Razmara M, Heldin CH, Lennartsson J. Platelet-derived growth factor-induced Akt phosphorylation requires mTOR/Rictor and phospholipase C-γ1, whereas S6 phosphorylation depends on mTOR/Raptor and phospholipase D. Cell Commun Signal 2013; 11:3. [PMID: 23311350 PMCID: PMC3560233 DOI: 10.1186/1478-811x-11-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 01/09/2013] [Indexed: 11/10/2022] Open
Abstract
Mammalian target of rapamycin (mTOR) can be found in two multi-protein complexes, i.e. mTORC1 (containing Raptor) and mTORC2 (containing Rictor). Here, we investigated the mechanisms by which mTORC1 and mTORC2 are activated and their downstream targets in response to platelet-derived growth factor (PDGF)-BB treatment. Inhibition of phosphatidylinositol 3-kinase (PI3K) inhibited PDGF-BB activation of both mTORC1 and mTORC2. We found that in Rictor-null mouse embryonic fibroblasts, or after prolonged rapamycin treatment of NIH3T3 cells, PDGF-BB was not able to promote phosphorylation of Ser473 in the serine/threonine kinase Akt, whereas Thr308 phosphorylation was less affected, suggesting that Ser473 in Akt is phosphorylated in an mTORC2-dependent manner. This reduction in Akt phosphorylation did not influence the phosphorylation of the S6 protein, a well established protein downstream of mTORC1. Consistently, triciribine, an inhibitor of the Akt pathway, suppressed PDGF-BB-induced Akt phosphorylation without having any effect on S6 phosphorylation. Thus, mTORC2 does not appear to be upstream of mTORC1. We could also demonstrate that in Rictor-null cells the phosphorylation of phospholipase Cγ1 (PLCγ1) and protein kinase C (PKC) was impaired, and the PKCα protein levels strongly reduced. Furthermore, interfering with the PLCγ/Ca2+/PKC pathway inhibited PDGF-BB-induced Akt phosphorylation. In addition, PDGF-BB-induced activation of mTORC1, as measured by phosphorylation of the downstream S6 protein, was dependent on phospholipase D (PLD). It has been shown that Erk1/2 MAP-kinase directly phosphorylates and activates mTORC1; in partial agreement with this finding, we found that a Mek1/2 inhibitor delayed S6 phosphorylation in response to PDGF-BB, but it did not block it. Thus, whereas both mTORC1 and mTORC2 are activated in a PI3K-dependent manner, different additional signaling pathways are needed. mTORC1 is activated in a PLD-dependent manner and promotes phosphorylation of the S6 protein, whereas mTORC2, in concert with PLCγ signaling, promotes Akt phosphorylation.
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Affiliation(s)
- Masoud Razmara
- Ludwig Institute for Cancer Research, Science for life laboratory, Box 595, Biomedical Center, SE-751 24, Uppsala, Sweden.
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10
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Wallert M, McCoy A, Voog J, Rastedt D, Taves-Patterson J, Korpi-Steiner N, Canine J, Ngyuen T, Nguyen C, Provost J. α1 -Adrenergic receptor-induced cytoskeletal organization and cell motility in CCL39 fibroblasts requires phospholipase D1. J Cell Biochem 2012; 112:3025-34. [PMID: 21678474 DOI: 10.1002/jcb.23227] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The role of phospholipase D (PLD) in cytoskeletal reorganization, ERK activation, and migration is well established. Both isoforms of PLD (PLD1 and PLD2) can independently activate stress fiber formation and increase ERK phosphorylation. However, the isoform's specificity, upstream activators, and downstream targets of PLD that coordinate this process are less well understood. This study explores the role of α(1) -adrenergic receptor stimulation and its effect on PLD activity. We demonstrate that PLD1 activators, RhoA, and PKCα are critical for stress fiber formation and ERK activation, and enhance the production of phosphatidic acid (PA) upon phenylephrine addition. Ectopic expression of dominant negative PLD1 and not PLD2 blocks ERK activation, inhibits stress fiber formation, and reduces cell motility in CCL39 fibroblasts. Furthermore, we demonstrate the mechanism for PLD1 activation of ERK involves Ras. This work indicates that PLD1 plays a novel role mediating growth factor and cell motility events in α(1) -adrenergic receptor-activated cells.
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Affiliation(s)
- M Wallert
- Departments of Biosciences and Chemistry, Minnesota State University Moorhead, Moorhead, Minnesota 56563, USA
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11
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Marchini-Alves CMM, Nicoletti LM, Mazucato VM, de Souza LB, Hitomi T, Alves CDP, Jamur MC, Oliver C. Phospholipase D2: a pivotal player modulating RBL-2H3 mast cell structure. J Histochem Cytochem 2012; 60:386-96. [PMID: 22344748 DOI: 10.1369/0022155412438886] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The current study examined the role of PLD2 in the maintenance of mast cell structure. Phospholipase D (PLD) catalyzes hydrolysis of phosphatidylcholine to produce choline and phosphatidic acid (PA). PLD has two isoforms, PLD1 and PLD2, which vary in expression and localization depending on the cell type. The mast cell line RBL-2H3 was transfected to overexpress catalytically active (PLD2CA) and inactive (PLD2CI) forms of PLD2. The results of this study show that PLD2CI cells have a distinct star-shaped morphology, whereas PLD2CA and RBL-2H3 cells are spindle shaped. In PLD2CI cells, the Golgi complex was also disorganized with dilated cisternae, and more Golgi-associated vesicles were present as compared with the PLD2CA and RBL-2H3 cells. Treatment with exogenous PA led to the restoration of the wild-type Golgi complex phenotype in PLD2CI cells. Conversely, treatment of RBL-2H3 and PLD2CA cells with 1% 1-Butanol led to a disruption of the Golgi complex. The distribution of acidic compartments, including secretory granules and lysosomes, was also modified in PLD2CI cells, where they concentrated in the perinuclear region. These results suggest that the PA produced by PLD2 plays an important role in regulating cell morphology in mast cells.
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Affiliation(s)
- Claudia Maria Meirelles Marchini-Alves
- Department of Cell and Molecular Biology and Bioagents Pathogenic, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
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Kolesnikov YS, Nokhrina KP, Kretynin SV, Volotovski ID, Martinec J, Romanov GA, Kravets VS. Molecular structure of phospholipase D and regulatory mechanisms of its activity in plant and animal cells. BIOCHEMISTRY (MOSCOW) 2012; 77:1-14. [DOI: 10.1134/s0006297912010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Lee YH, Uhm JS, Yoon SH, Kang JY, Kim EK, Kang BS, Min DS, Bae YS. The C-terminal domain of PLD2 participates in degradation of protein kinase CKII β subunit in human colorectal carcinoma cells. BMB Rep 2011; 44:572-7. [DOI: 10.5483/bmbrep.2011.44.9.572] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Danne O, Möckel M. Choline in acute coronary syndrome: an emerging biomarker with implications for the integrated assessment of plaque vulnerability. Expert Rev Mol Diagn 2010; 10:159-71. [PMID: 20214535 DOI: 10.1586/erm.10.2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Whole-blood choline, plasma choline and serum choline are emerging biomarkers in acute coronary syndrome related to coronary plaque instability with platelet thrombus formation and ischemia. Whole-blood choline is an early predictor for cardiac events, which adds to troponins, natriuretic peptides and inflammatory markers. Serum choline is highly predictive for myocardial infarction and discriminates high- from low-risk subgroups in troponin-positive patients. Choline is a candidate marker to aid decision making in the emergency room in the upcoming era of sensitive troponin tests and the growing need to differentiate between ischemic and nonischemic etiologies of troponin elevations. The integrated approach of in vitro choline measurement in combination with advanced techniques of in vivo choline imaging represents a novel future strategy for detecting vulnerable plaques. This paper provides an up-to-date review of choline in acute coronary syndrome including key aspects of pathophysiology, analytical methods, clinical studies and implications for the integrated assessment of plaque vulnerability.
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Affiliation(s)
- Oliver Danne
- Department of Medicine, Internal Intensive Care and Nephrology, Charité - Universitätsmedizin Berlin/Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin, Germany.
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