1
|
Liu P, Zhu W, Chen C, Yan B, Zhu L, Chen X, Peng C. The mechanisms of lysophosphatidylcholine in the development of diseases. Life Sci 2020; 247:117443. [DOI: 10.1016/j.lfs.2020.117443] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/11/2020] [Accepted: 02/17/2020] [Indexed: 02/07/2023]
|
2
|
Corrêa R, Silva LFF, Ribeiro DJS, Almeida RDN, Santos IDO, Corrêa LH, de Sant'Ana LP, Assunção LS, Bozza PT, Magalhães KG. Lysophosphatidylcholine Induces NLRP3 Inflammasome-Mediated Foam Cell Formation and Pyroptosis in Human Monocytes and Endothelial Cells. Front Immunol 2020; 10:2927. [PMID: 31998284 PMCID: PMC6962110 DOI: 10.3389/fimmu.2019.02927] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/28/2019] [Indexed: 12/04/2022] Open
Abstract
Foam cells are specialized lipid-loaded macrophages derived from monocytes and are a key pathological feature of atherosclerotic lesions. Lysophosphatidylcholine (LPC) is a major lipid component of the plasma membrane with a broad spectrum of proinflammatory activities and plays a key role in atherosclerosis. However, the role of LPC in lipid droplet (LD) biogenesis and the modulation of inflammasome activation is still poorly understood. In the present study, we investigated whether LPC can induce foam cell formation through an analysis of LD biogenesis and determined whether the cell signaling involved in this process is mediated by the inflammasome activation pathway in human endothelial cells and monocytes. Our results showed that LPC induced foam cell formation in both types of cells by increasing LD biogenesis via a NLRP3 inflammasome-dependent pathway. Furthermore, LPC induced pyroptosis in both cells and the activation of the inflammasome with IL-1β secretion, which was dependent on potassium efflux and lysosomal damage in human monocytes. The present study described the IL-1β secretion and foam cell formation triggered by LPC via an inflammasome-mediated pathway in human monocytes and endothelial cells. Our results will help improve our understanding of the relationships among LPC, LD biogenesis, and NLRP3 inflammasome activation in the pathogenesis of atherosclerosis.
Collapse
Affiliation(s)
- Rafael Corrêa
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - Luís Felipe Fonseca Silva
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | | | - Raquel das Neves Almeida
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - Igor de Oliveira Santos
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - Luís Henrique Corrêa
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - Lívia Pimentel de Sant'Ana
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | | | - Patrícia T Bozza
- Laboratory of Immunopharmacology, Institute of Oswaldo Cruz-Fiocruz, Rio de Janeiro, Brazil
| | - Kelly Grace Magalhães
- Laboratory of Immunology and Inflammation, Department of Cell Biology, University of Brasília, Brasilia, Brazil
| |
Collapse
|
3
|
Piccirillo AR, Hyzny EJ, Beppu LY, Menk AV, Wallace CT, Hawse WF, Buechel HM, Wong BH, Foo JC, Cazenave-Gassiot A, Wenk MR, Delgoffe GM, Watkins SC, Silver DL, D'Cruz LM. The Lysophosphatidylcholine Transporter MFSD2A Is Essential for CD8 + Memory T Cell Maintenance and Secondary Response to Infection. THE JOURNAL OF IMMUNOLOGY 2019; 203:117-126. [PMID: 31127034 DOI: 10.4049/jimmunol.1801585] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/29/2019] [Indexed: 01/09/2023]
Abstract
Access to nutrients is critical for an effective T cell immune response to infection. Although transporters for sugars and amino acids have previously been described in the context of the CD8+ T cell immune response, the active transport of exogenous fatty acids has remained enigmatic. In this study, we discovered that the sodium-dependent lysophosphatidylcholine (LPC) transporter major facilitator superfamily domain containing 2A (MFSD2A) is upregulated on activated CD8+ T cells and is required for memory T cell maintenance. MFSD2A deficiency in mice resulted in decreased import of LPC esterified to long chain fatty acids into activated CD8+ T cells, and MFSD2A-deficient cells are at a competitive disadvantage resulting in reduced memory T cell formation and maintenance and reduced response to secondary infection. Mechanistically, import of LPCs was required to maintain T cell homeostatic turnover, which when lost resulted in a decreased memory T cell pool and thus a reduced secondary response to repeat infection.
Collapse
Affiliation(s)
- Ann R Piccirillo
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Eric J Hyzny
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Lisa Y Beppu
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Ashley V Menk
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232
| | - Callen T Wallace
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15213
| | - William F Hawse
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Heather M Buechel
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Bernice H Wong
- Signature Research Program in Cardiovascular and Metabolic Diseases, Duke-National University of Singapore Graduate Medical School, Singapore 159857, Singapore; and
| | - Juat Chin Foo
- Department of Biochemistry, National University of Singapore, Singapore 117597, Singapore
| | | | - Markus R Wenk
- Department of Biochemistry, National University of Singapore, Singapore 117597, Singapore
| | - Greg M Delgoffe
- Tumor Microenvironment Center, UPMC Hillman Cancer Center, Pittsburgh, PA 15232
| | - Simon C Watkins
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15213
| | - David L Silver
- Signature Research Program in Cardiovascular and Metabolic Diseases, Duke-National University of Singapore Graduate Medical School, Singapore 159857, Singapore; and
| | - Louise M D'Cruz
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213;
| |
Collapse
|
4
|
Liang L, Li Y, Tian X, Zhou J, Zhong L. Comprehensive lipidomic, metabolomic and proteomic profiling reveals the role of immune system in vitiligo. Clin Exp Dermatol 2019; 44:e216-e223. [PMID: 30859585 DOI: 10.1111/ced.13961] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Vitiligo is a common depigmentation disorder resulting from destruction of melanocytes, and has both genetic and environmental influences. Although genomic analyses have been performed to investigate the pathogenesis of vitiligo, the lipidomics, metabolomics and proteomics of serum have not been reported, and the role of small molecules and serum proteins in vitiligo remains unknown. AIM To study the metabolite and protein profiles in patients with vitiligo and healthy controls (HCs). METHODS Plasma samples from 60 participants (29 patients with vitiligo and 31 HCs) were analysed. Untargeted lipidomics, metabolomics and isobaric tags for relative and absolute quantification-based proteomics were performed using high performance liquid chromatography-tandem mass spectrometry. In addition, to validate differentially expressed metabolites in patients with vitiligo, plasma enzyme-linked immunosorbent assay was performed. RESULTS We identified differential expression of several metabolites and proteins involved in the immune system. Among these metabolites and proteins, lysophosphatidylcholine, platelet-activating factor, sn-glycerol-3-phosphocholine, succinic acid, CXCL4 and CXCL7 were significantly elevated in the plasma of patients with vitiligo, while aspartate was downregulated. CONCLUSION Our study has characterized several serum metabolites and proteins that could be potential candidate biomarkers in vitiligo, and provides a comprehensive insight into the role of immune system and aspartate metabolism in vitiligo.
Collapse
Affiliation(s)
- L Liang
- Department of Biophysics and, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Y Li
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - X Tian
- Jilin People's Hospital, Jilin, China
| | - J Zhou
- Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.,Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Beihang University, Beijing, 100191, China
| | - L Zhong
- Center of Medical and Health Analysis, Peking University Health Science Center, Beijing, China
| |
Collapse
|
5
|
Kulkarni YM, Dutta S, Iyer AKV, Wright CA, Ramesh V, Kaushik V, Semmes OJ, Azad N. A Lipidomics Approach to Identifying Key Lipid Species Involved in VEGF-Inhibitor Mediated Attenuation of Bleomycin-Induced Pulmonary Fibrosis. Proteomics Clin Appl 2018; 12:e1700086. [PMID: 29283216 DOI: 10.1002/prca.201700086] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 11/14/2017] [Indexed: 12/21/2022]
Abstract
PURPOSE Poor molecular characterization of idiopathic pulmonary fibrosis (IPF) has led to insufficient understanding of the pathogenesis of the disease, resulting in lack of effective therapies and poor prognosis. Particularly, the role of lipid imbalance due to impaired lipid metabolism in the pathogenesis of IPF has been poorly studied. EXPERIMENTAL DESIGN The authors have used shotgun lipidomics in a bleomycin (BLM) mouse model of pulmonary fibrosis with vascular endothelial growth factor (VEGF)-inhibitor CBO-P11 as a therapeutic measure, to identify a comprehensive set of lipids that contribute to the pathogenesis of pulmonary fibrosis. RESULTS The authors report that attenuation of BLM-induced fibrotic response with CBO-P11 cotreatment is accompanied by a decrease in total lipid content and specific downregulation of lipids, which are upregulated in response to BLM treatment. CONCLUSION AND CLINICAL RELEVANCE Dysregulated lipids identified in this study hold the potential of being future biomarkers for IPF.
Collapse
Affiliation(s)
- Yogesh M Kulkarni
- Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA, USA
| | - Sucharita Dutta
- Leroy T. Canoles Jr., Cancer Research Center, Eastern Virginia Medical School, Norfolk, VA,, USA
| | - Anand Krishnan V Iyer
- Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA, USA
| | - Clayton A Wright
- Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA, USA
| | - Vani Ramesh
- Department of Obstetrics and Gynecology, The Jones Institute for Reproductive Medicine, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Vivek Kaushik
- Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA, USA
| | - Oliver John Semmes
- Leroy T. Canoles Jr., Cancer Research Center, Eastern Virginia Medical School, Norfolk, VA,, USA.,Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Neelam Azad
- Department of Pharmaceutical Sciences, School of Pharmacy, Hampton University, Hampton, VA, USA
| |
Collapse
|
6
|
Cho WH, Park T, Park YY, Huh JW, Lim CM, Koh Y, Song DK, Hong SB. Clinical significance of enzymatic lysophosphatidylcholine (LPC) assay data in patients with sepsis. Eur J Clin Microbiol Infect Dis 2011; 31:1805-10. [PMID: 22167258 DOI: 10.1007/s10096-011-1505-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 11/23/2011] [Indexed: 01/06/2023]
Abstract
Lysophosphatidylcholine (LPC) has been suggested to serve as a useful prognostic marker for sepsis. However, existing LPC assays are complicated, time-consuming, and of limited application in real clinical situations. Thus, we investigated the serum LPC levels in sepsis patients using an enzymatic assay and analyzed the correlations between the serum LPC concentration and clinical characteristics. We prospectively collected blood samples from suspected sepsis patients, commencing on day 1 of sepsis. We analyzed all samples using an enzymatic assay. Additionally, we analyzed the serum LPC concentrations in a control group of 21 healthy blood donors. A total of 105 patients who fulfilled the sepsis criteria were included. The mean serum LPC concentration was 43.49 ± 33.09 μmol/L in sepsis patients, which was much lower than that of 21 healthy controls (234.68 ± 30.33 μmol/L, p<0.001). Bacteremic sepsis was associated with a lower serum LPC concentration than non-bacteremic sepsis (34.8 ± 26.85 vs. 49.05 ± 35.63 μmol/L, p<0.05). No difference in serum LPC concentration was evident between survivors and non-survivors. The serum LPC concentration tended to decrease with the severity of sepsis. The day 1 serum LPC concentration was decreased in patients with sepsis, especially when bacteremia was present. However, the serum LPC level did not correlate with disease severity and did not predict mortality from sepsis.
Collapse
Affiliation(s)
- W H Cho
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan, Korea
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Efficient CRM197-mediated drug targeting to monocytes. J Control Release 2011; 158:139-47. [PMID: 21982901 DOI: 10.1016/j.jconrel.2011.09.091] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 01/04/2023]
Abstract
Efficient delivery of drugs to specific cellular reservoirs is of particular importance for therapeutics that are not able to pass cellular barriers and that may have unwanted side effects in off-target tissues. Heparin-binding epidermal growth factor (HB-EGF) is expressed on leukocytes and may be targeted for specific drug delivery using cross-reacting material (CRM)197, a non-toxic variant of diphtheria toxin and exogenous substrate for HB-EGF. We used fluorescently labeled CRM197 and CRM197-coated liposomes to investigate their potential use for drug delivery to leukocytes. We demonstrate that CRM197-guided systems are efficiently taken up by human leukocytes in vitro. CRM197 was also found to specifically target leukocytes in vivo in mice with components of the human immune system (HIS mice) and hamsters. Monocytes represent the most prominent subset of leukocytes that showed highly specific CRM197-mediated uptake. We therefore propose the application of CRM197 as a novel targeting approach in diseases that require the selective treatment of monocytes.
Collapse
|
8
|
Costantini C, Micheletti A, Calzetti F, Perbellini O, Pizzolo G, Cassatella MA. Neutrophil activation and survival are modulated by interaction with NK cells. Int Immunol 2010; 22:827-38. [PMID: 20739460 DOI: 10.1093/intimm/dxq434] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
It is increasingly evident that neutrophils are able to cross-talk with other leukocytes to shape ongoing inflammatory and immune responses. In this study, we analyzed whether human NK cells may influence the survival and activation of neutrophils under co-culture conditions. We report that NK cells exposed to either IL-15 or IL-18 alone strongly protect the survival of neutrophils via the release of IFNγ and granulocyte macrophage colony-stimulating factor (GM-CSF) plus IFNγ, respectively, and cause a slight up-regulation of neutrophil CD64 and CD11b expression. In comparison, NK cells exposed to both IL-15 and IL-18 show a lesser ability to increase the survival of neutrophils but can more potently up-regulate CD64 and CD11b expression, as well as induce the de novo surface expression of CD69, in neutrophils. Analysis of the events occurring in neutrophil/NK co-cultures exposed to IL-15 plus IL-18 revealed that (i) neutrophil survival is positively affected by NK-derived GM-CSF but negatively influenced by a CD18-dependent neutrophil/NK contact, (ii) NK-derived IFNγ is almost entirely responsible for the induction of CD64, (iii) both soluble factors (primarily GM-CSF) and direct cell-cell contact up-regulate CD11b and CD69 and (iv) NK-derived GM-CSF induces the expression of biologically active heparin-binding EGF-like growth factor (HB-EGF) in neutrophils. Finally, we demonstrate that NK cells can also express HB-EGF when stimulated with either IL-2 or IL-15, yet independently of endogenous GM-CSF. Altogether, our results define a novel interaction within the innate immune system whereby NK cells, by directly modulating neutrophil functions, might contribute to the pathogenesis of inflammatory diseases.
Collapse
Affiliation(s)
- Claudio Costantini
- Department of Pathology and Diagnostics, Division of General Pathology, University of Verona, Strada Le Grazie 8, Verona 37134, Italy
| | | | | | | | | | | |
Collapse
|
9
|
Schmitz G, Ruebsaamen K. Metabolism and atherogenic disease association of lysophosphatidylcholine. Atherosclerosis 2009; 208:10-8. [PMID: 19570538 DOI: 10.1016/j.atherosclerosis.2009.05.029] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 04/27/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
Abstract
Lysophosphatidylcholine (LPC) is a major plasma lipid that has been recognized as an important cell signalling molecule produced under physiological conditions by the action of phospholipase A(2) on phosphatidylcholine. LPC transports glycerophospholipid components such as fatty acids, phosphatidylglycerol and choline between tissues. LPC is a ligand for specific G protein-coupled signalling receptors and activates several second messengers. LPC is also a major phospholipid component of oxidized low-density lipoproteins (Ox-LDL) and is implicated as a critical factor in the atherogenic activity of Ox-LDL. Hence, LPC plays an important role in atherosclerosis and acute and chronic inflammation. In this review we focus in some detail on LPC function, biochemical pathways, sources and signal-transduction system. Moreover, we outline the detection of LPC by mass spectrometry which is currently the best method for accurate and simultaneous analysis of each individual LPC species and reveal the pathophysiological implication of LPC which makes it an interesting target for biomarker and drug development regarding atherosclerosis and cardiovascular disorders.
Collapse
Affiliation(s)
- Gerd Schmitz
- Institute for Clinical Chemistry and Laboratory Medicine, University of Regensburg, Regensburg, Germany.
| | | |
Collapse
|
10
|
Ali M, Madjid M. Lipoprotein-associated phospholipase A2: a cardiovascular risk predictor and a potential therapeutic target. Future Cardiol 2009; 5:159-73. [DOI: 10.2217/14796678.5.2.159] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Lipoprotein-associated phospholipase A2 (Lp-PLA2), present in the circulation and in atherosclerotic plaque, is an inflammatory marker with potential use as a predictor of cardiovascular risk and as a therapeutic target. Although Lp-PLA2 is associated with both LDL and HDL, it is important to determine whether Lp-PLA2 has a predominantly pro- or anti-atherogenic effect. Increasing evidence suggests a proatherogenic role for Lp-PLA2. ©iEpidemiologic and clinical evidence suggests Lp-PLA2 is an independent predictor of risk and may be superior to other inflammatory markers owing to its specificity and minimal biovariation. Lp-PLA2 inhibitors currently being investigated in clinical trials are promising novel anti-inflammatory agents with a specificity for the vascular bed and a potential for decreasing plaque vulnerability.
Collapse
Affiliation(s)
- Muzammil Ali
- Texas Heart Institute, 6770 Bertner Ave, MC 2-255, Houston, TX 77030, USA
| | - Mohammad Madjid
- Texas Heart Institute at St Luke’s Episcopal Hospital, The University of Texas Health Science Center at Houston, Houston, TX, USA
| |
Collapse
|
11
|
Karasawa K. Clinical aspects of plasma platelet-activating factor-acetylhydrolase. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1359-72. [PMID: 17049457 DOI: 10.1016/j.bbalip.2006.06.017] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Accepted: 06/15/2006] [Indexed: 11/25/2022]
Abstract
Plasma platelet-activating factor (PAF)-acetylhydrolase (PAF-AH), which is characterized by tight association with plasma lipoproteins, degrades not only PAF but also phospholipids with oxidatively modified short fatty acyl chain esterified at the sn-2 position. Production and accumulation of these phospholipids are associated with the onset of inflammatory diseases and preventive role of this enzyme has been evidenced by many recent studies including prevalence of the genetic deficiency of the enzyme in the patients and therapeutic effects of treatment with recombinant protein or gene transfer. With respect to the atherosclerosis, however, it is not fully cleared whether this enzyme plays an anti-atherogenic role or pro-atherogenic role because plasma PAF-AH also might produce lysophosphatidylcholine (LysoPC) and oxidatively modified nonesterified fatty acids with potent pro-inflammatory and pro-atherogenic bioactivities. These dual roles of plasma PAF-AH might be regulated by the altered distribution of the enzyme between low density lipoprotein (LDL) and high density lipoprotein (HDL) particles because HDL-associated enzymes are considered to contribute to the protection of LDL from oxidative modification. This review focuses on the recent findings which address the role of this enzyme in the human diseases especially including asthma, septic shock and atherosclerosis.
Collapse
Affiliation(s)
- Ken Karasawa
- Laboratory of Molecular Pharmaceutics, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamihara, Kanagawa 199-0195, Japan.
| |
Collapse
|
12
|
Dreux AC, Lamb DJ, Modjtahedi H, Ferns GAA. The epidermal growth factor receptors and their family of ligands: their putative role in atherogenesis. Atherosclerosis 2005; 186:38-53. [PMID: 16076471 DOI: 10.1016/j.atherosclerosis.2005.06.038] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 06/21/2005] [Accepted: 06/23/2005] [Indexed: 12/12/2022]
Abstract
The epidermal growth factor receptor is a member of type-I growth factor receptor family with tyrosine kinase activity that is activated following the binding of multiple cognate ligands. Several members of the EGF family of ligands are expressed by cells involved in atherogenesis. EGF receptor mediated processes have been well characterised within epithelial, smooth muscle and tumour cell lines in vitro, and the EGF receptor has been identified immunocytochemically on intimal smooth muscle cells within atherosclerotic plaques. There is also limited evidence for the expression of the EGF receptor family on leukocytes, although their function has yet to be clarified. In this review, we will discuss the biological functions of this receptor and its ligands and their potential to modulate the function of cells involved in the atherosclerotic process.
Collapse
Affiliation(s)
- Alys C Dreux
- Centre for Clinical Science & Measurement, School of Biomedical & Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
| | | | | | | |
Collapse
|
13
|
Sheikh AM, Ochi H, Masuda J. Lysophosphatidylcholine induces tPA gene expression through CRE-dependent mechanism. Biochem Biophys Res Commun 2005; 329:71-7. [PMID: 15721275 DOI: 10.1016/j.bbrc.2005.01.094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Indexed: 11/21/2022]
Abstract
Lysophosphatidylcholine (lysoPC) is implicated in the development of atherosclerosis and certain autoimmune diseases, and is reported to induce tissue-type plasminogen activator (tPA) at the protein level in endothelial cells. This study was designed to investigate the effect of lysoPC on tPA gene expression and the underlying molecular mechanisms in cultured endothelial cells. LysoPC transiently induced the mRNA expression of tPA in endothelial cells. LysoPC also induced the mRNA expression of urokinase-type plasminogen activator (uPA), uPA receptor, and plasminogen activator inhibitor-1, but the kinetics were different from that of tPA. Promoter analysis revealed that the cyclic AMP-responsive element of the tPA gene (tPACRE) is required for lysoPC-induced tPA expression. Furthermore, an electrophoresis mobility shift assay showed that lysoPC increased the binding activity of CRE binding protein to tPACRE. These results indicated that lysoPC transcriptionally upregulated the gene expression of tPA in endothelial cells, at least in part, via tPACRE activation.
Collapse
Affiliation(s)
- Abdullah Md Sheikh
- Department of Laboratory Medicine, Shimane University School of Medicine, Izumo, Japan
| | | | | |
Collapse
|
14
|
Chait A, Han CY, Oram JF, Heinecke JW. Thematic review series: The Immune System and Atherogenesis. Lipoprotein-associated inflammatory proteins: markers or mediators of cardiovascular disease? J Lipid Res 2005; 46:389-403. [PMID: 15722558 DOI: 10.1194/jlr.r400017-jlr200] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In humans, a chronically increased circulating level of C-reactive protein (CRP), a positive acute-phase reactant, is an independent risk factor for cardiovascular disease. This observation has led to considerable interest in the role of inflammatory proteins in atherosclerosis. In this review, after discussing CRP, we focus on the potential role in the pathogenesis of human vascular disease of inflammation-induced proteins that are carried by lipoproteins. Serum amyloid A (SAA) is transported predominantly on HDL, and levels of this protein increase markedly during acute and chronic inflammation in both animals and humans. Increased SAA levels predict the risk of cardiovascular disease in humans. Recent animal studies support the proposal that SAA plays a role in atherogenesis. Evidence is accruing that secretory phospholipase A(2), an HDL-associated protein, and platelet-activating factor acetylhydrolase, a protein associated predominantly with LDL in humans and HDL in mice, might also play roles both as markers and mediators of human atherosclerosis. In contrast to positive acute-phase proteins, which increase in abundance during inflammation, negative acute-phase proteins have received less attention. Apolipoprotein A-I (apoA-I), the major apolipoprotein of HDL, decreases during inflammation. Recent studies also indicate that HDL is oxidized by myeloperoxidase in patients with established atherosclerosis. These alterations may limit the ability of apoA-I to participate in reverse cholesterol transport. Paraoxonase-1 (PON1), another HDL-associated protein, also decreases during inflammation. PON1 is atheroprotective in animal models of hypercholesterolemia. Controversy over its utility as a marker of human atherosclerosis may reflect the fact that enzyme activity rather than blood level (or genotype) is the major determinant of cardiovascular risk. Thus, multiple lipoprotein-associated proteins that change in concentration during acute and chronic inflammation may serve as markers of cardiovascular disease. In future studies, it will be important to determine whether these proteins play a causal role in atherogenesis.
Collapse
Affiliation(s)
- Alan Chait
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98195, USA.
| | | | | | | |
Collapse
|
15
|
Mukai E, Kume N, Hayashida K, Minami M, Yamada Y, Seino Y, Kita T. Heparin-binding EGF-like growth factor induces expression of lectin-like oxidized LDL receptor-1 in vascular smooth muscle cells. Atherosclerosis 2004; 176:289-96. [PMID: 15380451 DOI: 10.1016/j.atherosclerosis.2004.03.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2003] [Revised: 10/23/2003] [Accepted: 03/30/2004] [Indexed: 11/15/2022]
Abstract
Receptor-mediated endocytosis of oxidized LDL (Ox-LDL) has been implicated in lipid accumulation and vascular cell dysfunction. Lectin-like Ox-LDL receptor-1 (LOX-1) is highly inducible by proinflammatory cytokines, as well as angiotensin II and Ox-LDL in vitro. LOX-1 is expressed in macrophages and smooth muscle cells accumulated in the intima of advanced atherosclerotic plaques in vivo. Here we show that heparin-binding epidermal growth factor-like growth factor (HB-EGF), a potent mitogen for vascular smooth muscle cells, induces LOX-1 expression in cultured bovine aortic smooth muscle cells. HB-EGF (1-100 ng/ml) induced LOX-1 expression, which was peaked between 8 and 16 h after HB-EGF stimulation. HB-EGF-induced expression of LOX-1 was suppressed by ZD1839, an inhibitor of EGF receptor phosphorylation. Both MEK and p38 mitogen-activated protein kinase (MAPK) inhibitors significantly blocked LOX-1 upregulation induced by HB-EGF. Phosphatidylinositol 3-kinase (PI3K) inhibitors also blocked HB-EGF-induced LOX-1 expression. HB-EGF induced phosphorylation of ERK, p38 MAPK and Akt, which were suppressed by ZD1839. Upregulated expression of LOX-1 was associated with enhanced uptake of DiI-labeled Ox-LDL in smooth muscle cells. Taken together, HB-EGF can also act as an inducer of LOX-1 expression and play an integral role in foam cell transformation, cellular dysfunction, and proliferation of smooth muscle cells in atherogenesis.
Collapse
Affiliation(s)
- Eri Mukai
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | | | | | | | | | | | | |
Collapse
|
16
|
Kostenis E. A glance at G-protein-coupled receptors for lipid mediators: a growing receptor family with remarkably diverse ligands. Pharmacol Ther 2004; 102:243-57. [PMID: 15246248 DOI: 10.1016/j.pharmthera.2004.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A plethora of lipid-like molecules known to act as intracellular second messengers are now recognized to signal cells through plasma membrane 7 transmembrane G-protein-coupled receptors (GPCRs). This has been the result of a decade-long genetic hunt for novel sequences encoding 7 transmembrane receptor proteins and the efforts to pair novel sequences with biologically active substances of (partly) unknown molecular mechanism of action. Identification of novel GPCR ligand pairs represents the first step to shed more light into the mode of action of novel cellular signaling molecules in human health and disease and might represent a fruitful source for the development of new drugs, judged on the successful history of GPCR as drug targets. Since 2000, more than 16 reports became available on lipid mediators--as diverse as lysophospholipids, arachidonic acid metabolites, short-, medium-, and long-chain fatty acids as well as steroid-like molecules--exerting their effects as extracellular mediators via rhodopsin-like family GPCRs. These reports have opened new avenues for research in human lipid receptor physiology and pharmacology. Here, the current knowledge on the recently deorphanized lipid receptors, including their isolation, expression pattern, function, and possible physiological or pathological roles will be reviewed.
Collapse
Affiliation(s)
- Evi Kostenis
- 7TM Pharma A/S, 3 Fremtidsvej, 2970 Hoersholm, Denmark.
| |
Collapse
|
17
|
Légrádi A, Chitu V, Szukacsov V, Fajka-Boja R, Székely Szücs K, Monostori E. Lysophosphatidylcholine is a regulator of tyrosine kinase activity and intracellular Ca(2+) level in Jurkat T cell line. Immunol Lett 2004; 91:17-21. [PMID: 14757365 DOI: 10.1016/j.imlet.2003.10.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lysophospholipids, particularly lysophosphatidylcholine (lyso-PC), have been implicated in modulating T cell functions at the sites of inflammation and atherosclerosis. Although the chemotactic and immunomodulatory effects are well documented, the exact signaling pathway of lyso-PC action is poorly defined. In this work, we studied the earliest biochemical events in T cells triggered by lyso-PC. A marked and immediate tyrosine phosphorylation was induced in the leukemic T cell line, Jurkat. Phosphorylation of cellular substrates included src family kinase, p56(lck) and syk family kinase, ZAP70. The lyso-PC induced tyrosine phosphorylation was largely dependent on the presence of functional p56(lck). Tyrosine phosphorylation was followed by the elevation of intracellular Ca(2+) concentration. The magnitude of the mobilization of the intracellular Ca(2+) was similar in the absence of the p56(lck) activity in JCaM1.6 cells as in Jurkat cells, however, it was slightly but reproducibly delayed compared to that in the wild type cells. Inhibition of the Ser/Thr kinases and tyrosine kinases with staurosporine and genistein, respectively, decreased the rise in the intracellular Ca(2+) content. Moreover, pertussis toxin completely blocked the Ca(2+) signal supporting the role of the G-protein coupled LPC receptor in this event.
Collapse
Affiliation(s)
- Adám Légrádi
- Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of Hungarian Academy of Sciences, PO Box 521, Temesvári krt. 62, H-6726 Szeged, Hungary
| | | | | | | | | | | |
Collapse
|
18
|
Yan JJ, Jung JS, Lee JE, Lee J, Huh SO, Kim HS, Jung KC, Cho JY, Nam JS, Suh HW, Kim YH, Song DK. Therapeutic effects of lysophosphatidylcholine in experimental sepsis. Nat Med 2004; 10:161-7. [PMID: 14716308 DOI: 10.1038/nm989] [Citation(s) in RCA: 257] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Accepted: 12/15/2003] [Indexed: 12/13/2022]
Abstract
Sepsis represents a major cause of death in intensive care units. Here we show that administration of lysophosphatidylcholine (LPC), an endogenous lysophospholipid, protected mice against lethality after cecal ligation and puncture (CLP) or intraperitoneal injection of Escherichia coli. In vivo treatment with LPC markedly enhanced clearance of intraperitoneal bacteria and blocked CLP-induced deactivation of neutrophils. In vitro, LPC increased bactericidal activity of neutrophils, but not macrophages, by enhancing H(2)O(2) production in neutrophils that ingested E. coli. Incubation with an antibody to the LPC receptor, G2A, inhibited LPC-induced protection from CLP lethality and inhibited the effects of LPC in neutrophils. G2A-specific antibody also blocked the inhibitory effects of LPC on certain actions of lipopolysaccharides (LPS), including lethality and the release of tumor necrosis factor-alpha (TNF-alpha) from neutrophils. These results suggest that LPC can effectively prevent and treat sepsis and microbial infections.
Collapse
Affiliation(s)
- Ji-Jing Yan
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, 1 Okchon-dong, Chunchon, Gangwon-do, 200-702, South Korea
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Ishizuka K, Miyamoto Y, Satsu H, Sato R, Shimizu M. Characteristics of lysophosphatidylcholine in its inhibition of taurine uptake by human intestinal Caco-2 cells. Biosci Biotechnol Biochem 2002; 66:730-6. [PMID: 12036043 DOI: 10.1271/bbb.66.730] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The characteristics of lysophosphatidylcholine (LPC) in its inhibition of the taurine uptake by human intestinal Caco-2 cells were investigated. By treating the cells with 200 microM of LPC, the taurine uptake was rapidly decreased by approximately 60%. This decrease was accompanied by an increase in the Km value for the uptake. A rapid uptake of LPC itself by the cells was also observed. The inhibitory activity of LPC was specific to the uptake of taurine and certain amino acids, while the uptake of glucose, glutamic acid and peptide (glycylglutamine) was not affected by LPC. The activity was dependent on the structure of a polar head and the bound fatty acid. The phosphorylcholine residue was likely to have played an important role, and surface active LPC with fatty acids of C14 or longer was highly inhibitory. These results suggest that the interaction of LPC with the taurine transporter in the intestinal cell membrane was the cause of the reduced taurine uptake.
Collapse
Affiliation(s)
- Koji Ishizuka
- Department of Applied Biological Chemistry, The University of Tokyo, Japan
| | | | | | | | | |
Collapse
|
20
|
Nishi E, Prat A, Hospital V, Elenius K, Klagsbrun M. N-arginine dibasic convertase is a specific receptor for heparin-binding EGF-like growth factor that mediates cell migration. EMBO J 2001; 20:3342-50. [PMID: 11432822 PMCID: PMC125525 DOI: 10.1093/emboj/20.13.3342] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a mitogen and chemotactic factor, binds to two receptor tyrosine kinases, erbB1 and erbB4. Now we demonstrate that HB-EGF also binds to a novel 140 kDa receptor on MDA-MB 453 cells. Purification of this receptor showed it to be identical to N-arginine dibasic convertase (NRDc), a metalloendopeptidase of the M16 family. Binding to cell surface NRDc and NRDc in solution was highly specific for HB-EGF among EGF family members. When overexpressed in cells, NRDc enhanced their migration in response to HB-EGF but not to EGF. Conversely, inhibition of endogenous NRDc expression in cells by antisense morpholino oligonucleotides inhibited HB-EGF-induced cell migration. Anti-erbB1 neutralizing antibodies completely abrogated the ability of NRDc to enhance HB-EGF-dependent migration, demonstrating that this NRDc activity was dependent on erbB1 signaling. Although NRDc is a metalloproteinase, enzymatic activity was not required for HB-EGF binding or enhancement of cell migration; neither did NRDc cleave HB-EGF. Together, these results suggest that NRDc is a novel specific receptor for HB-EGF that modulates HB-EGF-induced cell migration via erbB1.
Collapse
Affiliation(s)
- Eiichiro Nishi
- Departments of
Surgical Research and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA and Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, H2W 1R7, Canada Present address: Medicity Research Laboratories and the Department of Medical Biochemistry and Molecular Biology, University of Turku, FIN-20520 Turku, Finland Corresponding author e-mail:
| | - Annik Prat
- Departments of
Surgical Research and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA and Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, H2W 1R7, Canada Present address: Medicity Research Laboratories and the Department of Medical Biochemistry and Molecular Biology, University of Turku, FIN-20520 Turku, Finland Corresponding author e-mail:
| | - Véronique Hospital
- Departments of
Surgical Research and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA and Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, H2W 1R7, Canada Present address: Medicity Research Laboratories and the Department of Medical Biochemistry and Molecular Biology, University of Turku, FIN-20520 Turku, Finland Corresponding author e-mail:
| | - Klaus Elenius
- Departments of
Surgical Research and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA and Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, H2W 1R7, Canada Present address: Medicity Research Laboratories and the Department of Medical Biochemistry and Molecular Biology, University of Turku, FIN-20520 Turku, Finland Corresponding author e-mail:
| | - Michael Klagsbrun
- Departments of
Surgical Research and Pathology, Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA and Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, H2W 1R7, Canada Present address: Medicity Research Laboratories and the Department of Medical Biochemistry and Molecular Biology, University of Turku, FIN-20520 Turku, Finland Corresponding author e-mail:
| |
Collapse
|
21
|
Colles SM, Chisolm GM. Lysophosphatidylcholine-induced cellular injury in cultured fibroblasts involves oxidative events. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)33425-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
22
|
Kohjimoto Y, Honeyman TW, Jonassen J, Gravel K, Kennington L, Scheid CR. Phospholipase A2 mediates immediate early genes in cultured renal epithelial cells: possible role of lysophospholipid. Kidney Int 2000; 58:638-46. [PMID: 10916087 DOI: 10.1046/j.1523-1755.2000.00210.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Exposure to high levels of oxalate induces oxidant stress in renal epithelial cells and produces diverse changes in cell function, ranging from cell death to cellular adaptation, as evidenced by increased DNA synthesis, cellular proliferation, and induction of genes associated with remodeling and repair. These studies focused on cellular adaptation to this oxidant stress, examining the manner by which oxalate exposure leads to increased expression of immediate early genes (IEGs). Specifically, our studies assessed the possibility that oxalate-induced changes in IEG expression are mediated by phospholipase A2 (PLA2), a common pathway in cellular stress responses. METHODS Madin-Darby canine kidney (MDCK) cells were exposed to oxalate in the presence or absence of PLA2 inhibitors: mepacrine and arachidonyl trifluoromethyl ketone (AACOCF3). Expression of IEG (c-jun, egr-1, and c-myc) mRNA was assessed by Northern blot analysis. PLA2 activity was determined by measuring the release of [3H]arachidonic acid (AA) from prelabeled cells. RESULTS Oxalate exposure (1 to 1.5 mmol/L) induced time- and concentration-dependent increases in IEG mRNA. Treatment with mepacrine resulted in a 75 to 113% reduction of oxalate-induced c-jun, egr-1, and c-myc mRNA, while AACOCF3 caused a 41 to 46% reduction of oxalate-induced c-jun and egr-1 mRNA. Of the two major byproducts of PLA2, only lysophosphatidylcholine (20 micromol/L) increased c-jun and egr-1 mRNA. In contrast, AA (25 micromol/L) attenuated the oxalate-induced increase in c-jun and egr-1 mRNA, presumably by inhibiting PLA2 activity. CONCLUSIONS These findings suggest that PLA2 plays a major role in oxalate-induced IEG expression in renal epithelial cells and that lysophospholipids might be a possible lipid mediator in this pathway.
Collapse
Affiliation(s)
- Y Kohjimoto
- Department of Physiology, University of Massachusetts Medical School, Worcester 01655-0127, USA
| | | | | | | | | | | |
Collapse
|
23
|
Ueno Y, Kume N, Miyamoto S, Morimoto M, Kataoka H, Ochi H, Nishi E, Moriwaki H, Minami M, Hashimoto N, Kita T. Lysophosphatidylcholine phosphorylates CREB and activates the jun2TRE site of c-jun promoter in vascular endothelial cells. FEBS Lett 1999; 457:241-5. [PMID: 10471787 DOI: 10.1016/s0014-5793(99)01049-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Lysophosphatidylcholine (lyso-PC), a polar phospholipid increased in atherogenic lipoproteins and atherosclerotic lesions, has been shown to induce transcription of a variety of endothelial genes relevant to atherogenesis. Lyso-PC has been shown to activate c-jun N-terminal kinase (JNK) and activator protein 1 (AP-1) and thereby stimulate transcription of the c-jun gene. Here we provide evidence that lyso-PC can phosphorylate cyclic AMP responsive element binding protein (CREB) and thereby activate the jun2 12-O-tetradecanoylphorbol 13-acetate response element (jun2TRE) site of the c-jun promoter, which appears to be the major molecular mechanism involved in lyso-PC-induced c-jun gene expression in cultured bovine aortic endothelial cells (BAEC). Transient transfection of BAEC with a 1.6-kbp c-jun promoter and luciferase reporter fusion gene resulted in a 12.9-fold increase in luciferase activity by lyso-PC treatment. Serial deletion mutation in c-jun promoter and luciferase reporter gene assay revealed that the 5' promoter region between nucleotide numbers -268 and -127, which contains a jun2TRE binding sequence, was most crucial for lyso-PC-induced transcription. The 5' promoter region between -76 and -27, which contains an AP-1 site, also affected lyso-PC-induced transcription of the c-jun gene. Point mutation in the jun2TRE site reduced lyso-PC-induced transcription of the c-jun promoter-luciferase fusion gene by a 70.3% decrease in c-jun promoter activity. Electrophoretic mobility shift assays showed increased binding of (32)P-labeled oligonucleotides with jun2TRE in nuclear extracts isolated from lyso-PC-treated BAEC, which was abolished or supershifted by anti-CREB antibody. Immunoblotting with anti-phosphorylated CREB antibody showed rapid phosphorylation of this protein after lyso-PC treatment. These results indicate that lyso-PC phosphorylates CREB, which was then bound to the jun2TRE site of the c-jun promoter and activated transcription. Activation of jun2TRE may play a key role in the transcriptional activation of c-jun as well as other endothelial genes depending upon these transcription factors.
Collapse
Affiliation(s)
- Y Ueno
- Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Affiliation(s)
- A Wang
- Department of Chemistry and Biochemistry, Revelle College and School of Medicine, University of California at San Diego, La Jolla, CA 92093-0601, USA
| | | |
Collapse
|
25
|
Wang A, Yang HC, Friedman P, Johnson CA, Dennis EA. A specific human lysophospholipase: cDNA cloning, tissue distribution and kinetic characterization. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1437:157-69. [PMID: 10064899 DOI: 10.1016/s1388-1981(99)00012-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lysophospholipases are critical enzymes that act on biological membranes to regulate the multifunctional lysophospholipids; increased levels of lysophospholipids are associated with a host of diseases. Herein we report the cDNA cloning of a human brain 25 kDa lysophospholipid-specific lysophospholipase (hLysoPLA). The enzyme (at both mRNA and protein levels) is widely distributed in tissues, but with quite different abundances. The hLysoPLA hydrolyzes lysophosphatidylcholine in both monomeric and micellar forms, and exhibits apparent cooperativity and surface dilution kinetics, but not interfacial activation. Detailed kinetic analysis indicates that the hLysoPLA binds first to the micellar surface and then to the substrate presented on the surface. The kinetic parameters associated with this surface dilution kinetic model are reported, and it is concluded that hLysoPLA has a single substrate binding site and a surface recognition site. The apparent cooperativity observed is likely due to the change of substrate presentation. In contrast to many non-specific lipolytic enzymes that exhibit lysophospholipase activity, hLysoPLA hydrolyzes only lysophospholipids and has no other significant enzymatic activity. Of special interest, hLysoPLA does not act on plasmenylcholine. Of the several inhibitors tested, only methyl arachidonyl fluorophosphonate (MAFP) potently and irreversibly inhibits the enzymatic activity. The inhibition by MAFP is consistent with the catalytic mechanism proposed for the enzyme - a serine hydrolase with a catalytic triad composed of Ser-119, Asp-174 and His-208.
Collapse
Affiliation(s)
- A Wang
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093-0601, USA
| | | | | | | | | |
Collapse
|