51
|
Zhao Y, Natarajan V. Lysophosphatidic acid signaling in airway epithelium: role in airway inflammation and remodeling. Cell Signal 2009; 21:367-77. [PMID: 18996473 PMCID: PMC2660380 DOI: 10.1016/j.cellsig.2008.10.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 09/27/2008] [Accepted: 10/21/2008] [Indexed: 02/07/2023]
Abstract
Lysophosphatidic acid (LPA), a potent bioactive phospholipid, induces diverse cellular responses, including cell proliferation, migration, and cytokine release. LPA can be generated intracellularly and extracellularly through multiple synthetic pathways by action of various enzymes, such as phospholipase A(1/2) (PLA(1/2)), phospholipase D (PLD), acylglycerol kinase (AGK), and lysophospholipase D (lysoPLD). Metabolism of LPA is regulated by a family of lipid phosphate phosphatases (LPPs). Significant amounts of LPA have been detected in various biological fluids, including serum, saliva, and bronchoalveolar lavage fluid (BALF). The most significant effects of LPA appear to be through activation of the G-protein-coupled receptors (GPCRs), termed LPA(1-6). LPA regulates gene expression through activation of several transcriptional factors, such as nuclear factor-kappaB (NF-kappaB), AP-1, and C/EBPbeta. In addition to GPCRs, cross-talk between LPA receptors and receptor tyrosine kinases (RTKs) partly regulates LPA-induced intracellular signaling and cellular responses. Airway epithelial cells participate in innate immunity through the release of cytokines, chemokines, lipid mediators, other inflammatory mediators and an increase in barrier function in response to a variety of inhaled stimuli. Expression of LPA receptors has been demonstrated in airway epithelial cells. This review summarizes our recent observations of the role of LPA/LPA-Rs in regulation of airway epithelium, especially in relation to the secretion of pro- and anti-inflammatory mediators and regulation of airway barrier function.
Collapse
Affiliation(s)
- Yutong Zhao
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
| | | |
Collapse
|
52
|
Alexander SPH, Kendall DA. The life cycle of the endocannabinoids: formation and inactivation. Curr Top Behav Neurosci 2009; 1:3-35. [PMID: 21104378 DOI: 10.1007/978-3-540-88955-7_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this chapter, we summarise the current thinking about the nature of endocannabinoids. In describing the life cycle of these agents, we highlight the synthetic and catabolic enzymes suggested to be involved. For each of these, we provide a systematic analysis of information on sequence, subcellular and cellular distribution, as well as physiological and pharmacological substrates, enhancers and inhibitors, together with brief descriptions of the impact of manipulating enzyme levels through genetic mechanisms (dealt with in more detail in the chapter "Genetic Models of the Endocannabinoid System" by Monory and Lutz, this volume). In addition, we describe experiments investigating the stimulation of endocannabinoid synthesis and release in intact cell systems.
Collapse
Affiliation(s)
- Stephen P H Alexander
- School of Biomedical Sciences and Institute of Neuroscience, University of Nottingham Medical School, Queens Medical Centre, Nottingham, UK.
| | | |
Collapse
|
53
|
Foell JL, Hesse M, Volkmer I, Schmiedel BJ, Neumann I, Staege MS. Membrane-associated phospholipase A1 beta (LIPI) Is an Ewing tumour-associated cancer/testis antigen. Pediatr Blood Cancer 2008; 51:228-34. [PMID: 18435455 DOI: 10.1002/pbc.21602] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Cancer/testis antigens (CTA) represent a heterogeneous group of antigens expressed nearly exclusively in tumour cells and testis. Recently, we identified phospholipase A1 beta (a CTA also known as lipase member I, LIPI) as a gene with high expression in Ewing family tumours (EFT). In the present paper we analyzed expression of LIPI in a panel of normal tissues and tumour samples. PROCEDURE The expression of CTA in EFT and normal tissues was analyzed by using DNA microarray datasets. Expression of LIPI in EFT, a panel of other tumour samples, and normal tissues was analyzed by using RT-PCR and quantitative RT-PCR. RESULTS LIPI was expressed in EFT samples but not in other investigated tumour samples. Expression of LIPI in normal tissues was restricted to testis and thyroid. However, expression in these tissues was low compared with EFT. Interestingly testis as well as thyroid expressed all analyzed EFT-associated transcripts, suggesting that these tissues harbour a small cell population with molecular features of EFT. The sensitivity of the LIPI RT-PCR was similar to the sensitivity of the conventional EWSR1-FLI1 RT-PCR, suggesting that LIPI might be useful as additional diagnostic target structure. CONCLUSIONS The human cancer/testis antigen LIPI is highly expressed in Ewing family tumours and can be easily detected by RT-PCR or quantitative RT-PCR. LIPI might be an interesting target for the development of future diagnostic tools or treatment strategies.
Collapse
Affiliation(s)
- Juergen L Foell
- Department of Paediatrics, Children's Cancer Research Centre, Martin-Luther-University Halle-Wittenberg, 06097 Halle, Germany
| | | | | | | | | | | |
Collapse
|
54
|
Ye X. Lysophospholipid signaling in the function and pathology of the reproductive system. Hum Reprod Update 2008; 14:519-36. [PMID: 18562325 DOI: 10.1093/humupd/dmn023] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are two prominent signaling lysophospholipids (LPs) exerting their functions through a group of G protein-coupled receptors (GPCRs). This review covers current knowledge of the LP signaling in the function and pathology of the reproductive system. METHODS PubMed was searched up to May 2008 for papers on lysophospholipids/LPA/S1P/LPC/SPC in combination with each part of the reproductive system, such as testis/ovary/uterus. RESULTS LPA and SIP are found in significant amounts in serum and other biological fluids. To date, 10 LP receptors have been identified, including LPA(1-5) and S1P(1-5). In vitro and in vivo studies from the past three decades have demonstrated or suggested the physiological functions of LP signaling in reproduction, such as spermatogenesis, male sexual function, ovarian function, fertilization, early embryo development, embryo spacing, implantation, decidualization, pregnancy maintenance and parturition, as well as pathological roles in ovary, cervix, mammary gland and prostate cancers. CONCLUSIONS Receptor knock-out and other studies indicate tissue-specific and receptor-specific functions of LP signaling in reproduction. More comprehensive studies are required to define mechanisms of LP signaling and explore the potential use as a therapeutic target.
Collapse
Affiliation(s)
- Xiaoqin Ye
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| |
Collapse
|
55
|
Chang YJ, Kim YL, Jo JY, Kyeok K, Kim HL, Im DS. Dioleoyl phosphatidic acid induces morphological changes through an endogenous LPA receptor in C6 glioma cells. Arch Pharm Res 2008; 31:628-33. [PMID: 18481020 DOI: 10.1007/s12272-001-1204-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Indexed: 10/22/2022]
Abstract
Previously, we suggested that dioleoyl phosphatidic acid (PA) and lysophosphatidic acid (LPA) increased [Ca(2+)](i) through endogenous LPA receptors coupled to pertussis toxin-sensitive G proteins in rat C6 glioma cells. In the present report, we investigated morphological changes and cytotoxicity induced by PA and LPA in C6 glioma cells. Isoproterenol treatment led to changes in the cell morphology of rat C6 glioma cells, which were reverted by the addition of PA and LPA. PA-and LPA-induced morphological reversions were inhibited by treatment with Ki16425, an LPA(1)/LPA(3) receptor antagonist. VPC32183, another LPA(1)/LPA(3) receptor antagonist with a different structure, only inhibited PA-induced morphological reversion but not LPA-induced reversion. However, the reversions were not inhibited by treatment with pertussis toxin, a specific inhibitor of G(i/o) proteins. In addition, cytotoxicity was only induced by LPA but not by PA in C6 glioma cells. Our results suggest that PA may act as a partial agonist at endogenous LPA receptors, which are sensitive to Ki16425 and coupled to PTX-insensitive G proteins, to evoke morphological changes in C6 glioma cells.
Collapse
Affiliation(s)
- Young-Ja Chang
- Laboratory of Pharmacology, Pusan National University, Busan, Republic of Korea
| | | | | | | | | | | |
Collapse
|
56
|
Avendaño-Vázquez SE, Cabrera-Wrooman A, Colín-Santana CC, García-Sáinz JA. Lysophosphatidic acid LPA1 receptor close-up. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200700138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
57
|
Chang YJ, Kim HL, Sacket SJ, Kim KO, Han MJ, Jo JY, Im DS. Calcium Signaling of Dioleoyl Phosphatidic Acid via Endogenous LPA Receptors: A Study Using HCT116 and HT29 Human Colon Cancer Cell Lines. Biomol Ther (Seoul) 2007. [DOI: 10.4062/biomolther.2007.15.3.150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
58
|
Morita SY, Kobayashi A, Takanezawa Y, Kioka N, Handa T, Arai H, Matsuo M, Ueda K. Bile salt-dependent efflux of cellular phospholipids mediated by ATP binding cassette protein B4. Hepatology 2007; 46:188-99. [PMID: 17523162 DOI: 10.1002/hep.21591] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Human ABCB4 (multidrug resistance [MDR]3 P-glycoprotein) is expressed in the canalicular membrane of the hepatocyte. ABCB4 has been shown to be required for phosphatidylcholine (PC) secretion into the bile and to translocate PC across the plasma membrane. To further investigate the function of ABCB4, we established a cell line stably expressing ABCB4 (human embryonic kidney [HEK]/ABCB4). The efflux of phospholipids from HEK/ABCB4 cells was remarkably increased by the addition of taurocholate. In addition, the cholesterol efflux from HEK/ABCB4 cells was also enhanced in the presence of taurocholate. Light scattering measurements suggested that the taurocholate monomer plays an important role in ABCB4-mediated lipid secretion. On the other hand, the efflux of phospholipids and cholesterol was not mediated by ABCB1 (MDR1) even in the presence of taurocholate. Taurocholate promoted the efflux of phospholipids and cholesterol from HEK/ABCB4 cells more efficiently than glycocholate and cholate. ABCB4-K435M and ABCB4-K1075M, Walker A lysine mutants, did not mediate the phospholipid and cholesterol efflux in the presence of taurocholate, suggesting that ATP hydrolysis is essential for the efflux. Verapamil completely inhibited the taurocholate-dependent efflux of phospholipids and cholesterol from HEK/ABCB4 cells. Mass spectrometry revealed that, in the presence of taurocholate, HEK/ABCB4 cells preferentially secreted PC compared to sphingomyelin. PC vesicles induced cholesterol diffusion from cell membrane, but did not accept cholesterol from ABCB4. CONCLUSION ABCB4 mediates the efflux of phospholipids into the canalicular lumen in the presence of bile salts, and plays a crucial role in bile formation and lipid homeostasis.
Collapse
Affiliation(s)
- Shin-ya Morita
- Laboratory of Cellular Biochemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | | | | | | | | | | | | |
Collapse
|
59
|
Chang YJ, Kim YL, Lee YK, Sacket SJ, Kim K, Kim HL, Han M, Bae YS, Okajima F, Im DS. Dioleoyl phosphatidic acid increases intracellular Ca2+ through endogenous LPA receptors in C6 glioma and L2071 fibroblasts. Prostaglandins Other Lipid Mediat 2007; 83:268-76. [PMID: 17499746 DOI: 10.1016/j.prostaglandins.2007.01.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 01/21/2007] [Accepted: 01/26/2007] [Indexed: 11/29/2022]
Abstract
Phosphatidic acid (PA) increased intracellular Ca(2+) concentration ([Ca(2+)](i)) in C6 rat glioma and L2071 mouse fibroblast cells. Dioleoyl PA (PA, 18:1) was the most efficacious, followed by dipalmitoyl PA (16:0 PA) and dimyristoyl PA (14:0 PA). Lysophosphatidic acid (LPA) also increased the [Ca(2+)](i) in the both cells. PA desensitized LPA-induced Ca(2+) response completely in C6 cells, but partly in L2071 cells. Treatment of pertussis toxin (PTX), a specific inhibitor of G(i/o)-type G proteins, completely ameliorated LPA- and PA-induced Ca(2+) response in C6 cells. However, in L2071 cells, PTX inhibited PA-induced Ca(2+) increase by 80% and LPA-induced one by 20%. Ki16425, a specific inhibitor of LPA(1)/LPA(3) receptors, completely inhibited both LPA- and PA-induced Ca(2+) responses in C6 cells. On the other hand, in L2071 cells, Ki16425 completely inhibited PA-induced Ca(2+) response, but partly LPA-induced one. VPC32183, another specific inhibitor of LPA(1)/LPA(3) receptors, completely inhibited LPA- and PA-induced Ca(2+) responses in both C6 and L2071 cells. Therefore, PA and LPA appear to increase [Ca(2+)](i) through Ki16425/VPC32183-sensitive LPA receptor coupled to PTX-sensitive G proteins in C6 cells. In L2071 cells, however, LPA increases [Ca(2+)](i) through Ki16425-insensitive LPA receptor coupled to PTX-insensitive G proteins and Ki16425-sensitive LPA receptor coupled to PTX-sensitive G protein, whereas PA utilized only the latter pathway. Our results suggest that PA acts as a partial agonist on endogenous LPA receptors, which are sensitive to Ki16425 and coupled to PTX-sensitive G protein, but not on LPA receptors, which are not sensitive to Ki16425 and coupled to PTX-insensitive G protein.
Collapse
Affiliation(s)
- Young-Ja Chang
- Laboratory of Pharmacology, College of Pharmacy and Research Institute for Drug Development, Pusan National University, San 30, Jang-Jun-dong, Geum-Jung-gu, Busan 609-735, Republic of Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
60
|
Ban N, Matsumura Y, Sakai H, Takanezawa Y, Sasaki M, Arai H, Inagaki N. ABCA3 as a Lipid Transporter in Pulmonary Surfactant Biogenesis. J Biol Chem 2007; 282:9628-9634. [PMID: 17267394 DOI: 10.1074/jbc.m611767200] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ABCA3 protein is expressed predominantly at the limiting membrane of the lamellar bodies in alveolar type II cells, and mutations in the ABCA3 gene cause lethal respiratory distress in newborn infants. To investigate the function of ABCA3 protein, we generated Abca3-deficient mice by targeting Abca3. Full-term Abca3(-/-) newborn pups died within an hour after birth because of acute respiratory failure. Ultrastructural analysis revealed abnormally dense lamellar body-like organelles and no normal lamellar bodies in Abca3(-/-) alveolar type II cells. TLC and electrospray ionization mass spectrometry analyses of lipids in the pulmonary interstitium showed that phosphatidylcholine and phosphatidylglycerol, which contain palmitic acid and are abundant in normal surfactant lipids, were dramatically decreased in Abca3(-/-) lung. These findings indicate that ABCA3 plays an essential role in pulmonary surfactant lipid metabolism and lamellar body biogenesis, probably by transporting these lipids as substrates.
Collapse
Affiliation(s)
- Nobuhiro Ban
- Department of Physiology, Akita University School of Medicine, and Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Agency (JST), Akita 010-8543, Japan
| | - Yoshihiro Matsumura
- Department of Physiology, Akita University School of Medicine, and Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Agency (JST), Akita 010-8543, Japan
| | - Hiromichi Sakai
- Department of Physiology, Akita University School of Medicine, and Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Agency (JST), Akita 010-8543, Japan
| | - Yasukazu Takanezawa
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Mayumi Sasaki
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, and CREST-JST, Kyoto 606-8507, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nobuya Inagaki
- Department of Physiology, Akita University School of Medicine, and Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Agency (JST), Akita 010-8543, Japan; Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, and CREST-JST, Kyoto 606-8507, Japan.
| |
Collapse
|
61
|
Ali G, Chishti MS, Raza SI, John P, Ahmad W. A mutation in the lipase H (LIPH) gene underlie autosomal recessive hypotrichosis. Hum Genet 2007; 121:319-25. [PMID: 17333281 DOI: 10.1007/s00439-007-0344-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 02/05/2007] [Indexed: 12/01/2022]
Abstract
Hereditary hypotrichosis is a rare autosomal recessive disorder characterized by sparse hair on scalp and rest of the body of affected individuals. Two forms of such hypotrichosis LAH and AH have been mapped on chromosome 18q12.1 and 3q27, respectively. Mutations in desmogelin 4 (DSG4) gene have been reported to underlie LAH. Recently, a deletion mutation in Lipase H (LIPH) gene, located at AH locus, has been identified in two ethnic groups of Russian population. In the present study, a four generation Pakistani family with AH phenotype has been mapped to chromosome 3q27. Sequence analysis of candidate gene LIPH revealed a novel five base pair deletion mutation (c.346-350delATATA) in exon 2 of the gene leading to frameshift and downstream premature termination codon. The mutation reported in the family, presented here, is the second mutation identified in LIPH gene. The identification of a genetic defect in LIPH suggests that this enzyme regulates hair growth.
Collapse
Affiliation(s)
- Ghazanfar Ali
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | | | | | | | | |
Collapse
|
62
|
De Maria L, Vind J, Oxenbøll KM, Svendsen A, Patkar S. Phospholipases and their industrial applications. Appl Microbiol Biotechnol 2007; 74:290-300. [PMID: 17221199 DOI: 10.1007/s00253-006-0775-x] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 11/17/2006] [Accepted: 11/17/2006] [Indexed: 10/23/2022]
Abstract
Phospholipids are present in all living organisms. They are a major component of all biological membranes, along with glycolipids and cholesterol. Enzymes aimed at modifying phospholipids, namely, phospholipases, are consequently widespread in nature, playing very diverse roles from aggression in snake venom to signal transduction and digestion in humans. In this review, we give a general overview of phospholipases A1, A2, C and D from a sequence and structural perspective and their industrial application. The use of phospholipases in industrial processes has grown hand-in-hand with our ability to clone and express the genes in microbial hosts with commercially attractive amounts. Further, the use in industrial processes is increasing by optimizing the enzymes by protein engineering. Here, we give a perspective on the work done to date to express phospholipases in heterologous hosts and the efforts to optimize them by protein engineering. We will draw attention to the industrial processes where phospholipases play a key role and show how the use of a phospholipase for oil degumming leads to substantial environmental benefits. This illustrates a very general trend: the use of enzymes as an alternative to chemical processes to make products often provides a cleaner solution for the industrial processes. In a world with great demands on non-polluting, energy saving technical solutions--white biotechnology is a strong alternative.
Collapse
Affiliation(s)
- L De Maria
- Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd, Denmark,
| | | | | | | | | |
Collapse
|
63
|
Aoki J, Inoue A, Makide K, Saiki N, Arai H. Structure and function of extracellular phospholipase A1 belonging to the pancreatic lipase gene family. Biochimie 2007; 89:197-204. [PMID: 17101204 DOI: 10.1016/j.biochi.2006.09.021] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Accepted: 09/28/2006] [Indexed: 10/24/2022]
Abstract
Phospholipase A1 (PLA1) is an enzyme that hydrolyzes phospholipids and produces 2-acyl-lysophospholipids and fatty acids and is conserved in a wide range of organisms. Mammals have several enzymes that exhibit PLA1 activity in vitro. The extracellular PLA1s include phosphatidylserine (PS)-specific PLA1 (PS-PLA1), membrane-associated phosphatidic acid (PA)-selective PLA1s (mPA-PLA1alpha and mPA-PLA1beta), hepatic lipase (HL), endothelial lipase (EL) and pancreatic lipase-related protein 2 (PLRP2), all of which belong to the pancreatic lipase gene family. The former three PLA1s differ from other members in their substrate specificities, structural features and gene organizations, and form a subfamily in the pancreatic lipase gene family. PS-PLA1, mPA-PLA1alpha and mPA-PLA1beta exhibit only PLA1 activity, while HL, EL and PLRP2 show triacylglycerol-hydrolyzing activity in addition to PLA1 activity. The tertiary structures of lipases have two surface loops, the lid and the beta9 loop. The lid and the beta9 loop cover the active site in its closed conformation. An alignment of amino acid sequences of the pancreatic lipase gene family members revealed two molecular characteristics of PLA1s in the two surface loops. First, lipase members exhibiting PLA1 activity (PS-PLA1, mPA-PLA1alpha and mPA-PLA1beta, EL, guinea pig PLRP2 and PLA1 from hornet venom (DolmI)) have short lids. Second, PS-PLA1, mPA-PLA1alpha, mPA-PLA1beta and DolmI, which exhibit only PLA(1) activity, have short beta9 loops. Thus, the two surface loops appear to be involved in the ligand recognition. PS-PLA1 and mPA-PLA1s specifically hydrolyze PS and PA, respectively, producing their corresponding lysophospholipids. Lysophosphatidylserine and lysophosphatidic acid have been defined as lipid mediators with multiple biological functions. Thus, these PLA1s have a role in the production of these lysophospholipid mediators.
Collapse
Affiliation(s)
- Junken Aoki
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | | | | | | | | |
Collapse
|
64
|
|
65
|
|
66
|
Kazantseva A, Goltsov A, Zinchenko R, Grigorenko AP, Abrukova AV, Moliaka YK, Kirillov AG, Guo Z, Lyle S, Ginter EK, Rogaev EI. Human Hair Growth Deficiency Is Linked to a Genetic Defect in the Phospholipase Gene LIPH. Science 2006; 314:982-5. [PMID: 17095700 DOI: 10.1126/science.1133276] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The molecular mechanisms controlling human hair growth and scalp hair loss are poorly understood. By screening about 350,000 individuals in two populations from the Volga-Ural region of Russia, we identified a gene mutation in families who show an inherited form of hair loss and a hair growth defect. Affected individuals were homozygous for a deletion in the LIPH gene on chromosome 3q27, caused by short interspersed nuclear element-retrotransposon-mediated recombination. The LIPH gene is expressed in hair follicles and encodes a phospholipase called lipase H (alternatively known as membrane-associated phosphatidic acid-selective phospholipase A1alpha), an enzyme that regulates the production of bioactive lipids. These results suggest that lipase H participates in hair growth and development.
Collapse
Affiliation(s)
- Anastasiya Kazantseva
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont Street, Worcester, MA 01604, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
67
|
Okazaki H, Igarashi M, Nishi M, Tajima M, Sekiya M, Okazaki S, Yahagi N, Ohashi K, Tsukamoto K, Amemiya-Kudo M, Matsuzaka T, Shimano H, Yamada N, Aoki J, Morikawa R, Takanezawa Y, Arai H, Nagai R, Kadowaki T, Osuga JI, Ishibashi S. Identification of a novel member of the carboxylesterase family that hydrolyzes triacylglycerol: a potential role in adipocyte lipolysis. Diabetes 2006; 55:2091-7. [PMID: 16804080 DOI: 10.2337/db05-0585] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Molecular mechanisms underlying lipolysis, as defined by mobilization of fatty acids from adipose tissue, are not fully understood. A database search for enzymes with alpha/beta hydrolase folds, the GXSXG motif for serine esterase and the His-Gly dipeptide motif, has provided a previously unannotated gene that is induced during 3T3-L1 adipocytic differentiation. Because of its remarkable structural resemblance to triacylglycerol hydrolase (TGH) with 70.4% identity, we have tentatively designated this enzyme as TGH-2 and the original TGH as TGH-1. TGH-2 is also similar to TGH-1 in terms of tissue distribution, subcellular localization, substrate specificity, and regulation. Both enzymes are predominantly expressed in liver, adipose tissue, and kidney. In adipocytes, they are localized in microsome and fatcake. Both enzymes hydrolyzed p-nitophenyl butyrate, triolein, and monoolein but not diolein, cholesteryl oleate, or phospholipids; hydrolysis of short-chain fatty acid ester was 30,000-fold more efficient than that of long-chain fatty acid triacylglycerol. Fasting increased the expression of both genes in white adipose tissue, whereas refeeding suppressed their expression. RNA silencing of TGH-2 reduced isoproterenol-stimulated glycerol release by 10% in 3T3-L1 adipocytes, while its overexpression increased the glycerol release by 20%. Thus, TGH-2 may make a contribution to adipocyte lipolysis during period of increased energy demand.
Collapse
Affiliation(s)
- Hiroaki Okazaki
- Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
68
|
Kobayashi A, Takanezawa Y, Hirata T, Shimizu Y, Misasa K, Kioka N, Arai H, Ueda K, Matsuo M. Efflux of sphingomyelin, cholesterol, and phosphatidylcholine by ABCG1. J Lipid Res 2006; 47:1791-802. [PMID: 16702602 DOI: 10.1194/jlr.m500546-jlr200] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholesterol and phospholipids are essential to the body, but an excess of cholesterol or lipids is toxic and a risk factor for arteriosclerosis. ABCG1, one of the half-type ABC proteins, is thought to be involved in cholesterol homeostasis. To explore the role of ABCG1 in cholesterol homeostasis, we examined its subcellular localization and function. ABCG1 and ABCG1-K120M, a WalkerA lysine mutant, were localized to the plasma membrane in HEK293 cells stably expressing ABCG1 and formed a homodimer. A stable transformant expressing ABCG1 exhibited efflux of cholesterol and choline phospholipids in the presence of BSA, and the cholesterol efflux was enhanced by the presence of HDL, whereas cells expressing ABCG1-K120M did not, suggesting that ATP binding and/or hydrolysis is required for the efflux. Mass and TLC analyses revealed that ABCG1 and ABCA1 secrete several species of sphingomyelin (SM) and phosphatidylcholine (PC), and SMs were preferentially secreted by ABCG1, whereas PCs were preferentially secreted by ABCA1. These results suggest that ABCA1 and ABCG1 mediate the lipid efflux in different mechanisms, in which different species of phospholipids are secreted, and function coordinately in the removal of cholesterol and phospholipids from peripheral cells.
Collapse
Affiliation(s)
- Aya Kobayashi
- Laboratory of Cellular Biochemistry, Division of Applied Life Sciences, Kyoto University Graduate School of Agriculture, Kyoto 606-8502, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
69
|
Transcriptional regulation of lysophosphatidic acid-induced interleukin-8 expression and secretion by p38 MAPK and JNK in human bronchial epithelial cells. Biochem J 2006. [PMID: 16197369 DOI: 10.1042/bj20050891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
HBEpCs (human bronchial epithelial cells) contribute to airway inflammation by secreting a variety of cytokines and chemokines in response to allergens, pathogens, viruses and environmental toxins and pollutants. The potent neutrophil chemoattractant, IL-8 (interleukin-8), is a major cytokine secreted by HBEpCs. We have recently demonstrated that LPA (lysophosphatidic acid) stimulated IL-8 production in HBEpCs via protein kinase C delta dependent signal transduction. However, mechanisms of IL-8 expression and secretion are complex and involve multiple protein kinases and transcriptional factors. The present study was undertaken to investigate MAPK (mitogen-activated protein kinase) signalling in the transcriptional regulation of IL-8 expression and secretion in HBEpCs. Exposure of HBEpCs to LPA (1 microM) enhanced expression and secretion of IL-8 by 5-8-fold and stimulated threonine/tyrosine phosphorylation of ERK (extracellular-signal-regulated kinase), p38 MAPK and JNK (c-Jun N-terminal kinase). The LPA-induced secretion of IL-8 was blocked by the p38 MAPK inhibitor SB203580, by p38 MAPK siRNA (small interfering RNA), and by the JNK inhibitor JNK(i) II, but not by the MEK (MAPK/ERK kinase) inhibitor, PD98059. LPA enhanced the transcriptional activity of the IL-8 gene; that effect relied on activation of the transcriptional factors NF-kappaB (nuclear factor kappaB) and AP-1 (activator protein-1). Furthermore, SB203580 attenuated LPA-dependent phosphorylation of IkappaB (inhibitory kappaB), NF-kappaB and phospho-p38 translocation to the nucleus, NF-kappaB transcription and IL-8 promoter-mediated luciferase reporter activity, without affecting the JNK pathway and AP-1 transcription. Similarly, JNK(i) II only blocked LPA-mediated phosphorylation of JNK and c-Jun, AP-1 transcription and IL-8 promoter-mediated luciferase reporter activity, without blocking p38 MAPK-dependent NF-kappaB transcription. Additionally, siRNA for LPA(1-3) receptors partially blocked LPA-induced IL-8 production and activation of MAPKs. The LPA1 and LPA3 receptors, as compared with LPA2, were most efficient in transducing LPA-mediated IL-8 production. These results show an independent role for p38 MAPK and JNK in LPA-induced IL-8 expression and secretion via NF-kappaB and AP-1 transcription respectively in HBEpCs.
Collapse
|
70
|
Saatian B, Zhao Y, He D, Georas S, Watkins T, Spannhake E, Natarajan V. Transcriptional regulation of lysophosphatidic acid-induced interleukin-8 expression and secretion by p38 MAPK and JNK in human bronchial epithelial cells. Biochem J 2006; 393:657-68. [PMID: 16197369 PMCID: PMC1360718 DOI: 10.1042/bj20050791] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
HBEpCs (human bronchial epithelial cells) contribute to airway inflammation by secreting a variety of cytokines and chemokines in response to allergens, pathogens, viruses and environmental toxins and pollutants. The potent neutrophil chemoattractant, IL-8 (interleukin-8), is a major cytokine secreted by HBEpCs. We have recently demonstrated that LPA (lysophosphatidic acid) stimulated IL-8 production in HBEpCs via protein kinase C delta dependent signal transduction. However, mechanisms of IL-8 expression and secretion are complex and involve multiple protein kinases and transcriptional factors. The present study was undertaken to investigate MAPK (mitogen-activated protein kinase) signalling in the transcriptional regulation of IL-8 expression and secretion in HBEpCs. Exposure of HBEpCs to LPA (1 microM) enhanced expression and secretion of IL-8 by 5-8-fold and stimulated threonine/tyrosine phosphorylation of ERK (extracellular-signal-regulated kinase), p38 MAPK and JNK (c-Jun N-terminal kinase). The LPA-induced secretion of IL-8 was blocked by the p38 MAPK inhibitor SB203580, by p38 MAPK siRNA (small interfering RNA), and by the JNK inhibitor JNK(i) II, but not by the MEK (MAPK/ERK kinase) inhibitor, PD98059. LPA enhanced the transcriptional activity of the IL-8 gene; that effect relied on activation of the transcriptional factors NF-kappaB (nuclear factor kappaB) and AP-1 (activator protein-1). Furthermore, SB203580 attenuated LPA-dependent phosphorylation of IkappaB (inhibitory kappaB), NF-kappaB and phospho-p38 translocation to the nucleus, NF-kappaB transcription and IL-8 promoter-mediated luciferase reporter activity, without affecting the JNK pathway and AP-1 transcription. Similarly, JNK(i) II only blocked LPA-mediated phosphorylation of JNK and c-Jun, AP-1 transcription and IL-8 promoter-mediated luciferase reporter activity, without blocking p38 MAPK-dependent NF-kappaB transcription. Additionally, siRNA for LPA(1-3) receptors partially blocked LPA-induced IL-8 production and activation of MAPKs. The LPA1 and LPA3 receptors, as compared with LPA2, were most efficient in transducing LPA-mediated IL-8 production. These results show an independent role for p38 MAPK and JNK in LPA-induced IL-8 expression and secretion via NF-kappaB and AP-1 transcription respectively in HBEpCs.
Collapse
Affiliation(s)
- Bahman Saatian
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Yutong Zhao
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Donghong He
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Steve N. Georas
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Tonya Watkins
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
| | - Ernst Wm Spannhake
- †Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | - Viswanathan Natarajan
- *Division of Pulmonary and Critical Care Medicine and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, U.S.A
- To whom correspondence should be addressed (email )
| |
Collapse
|
71
|
Rose TM, Prestwich GD. Fluorogenic phospholipids as head group-selective reporters of phospholipase A activity. ACS Chem Biol 2006; 1:83-91. [PMID: 17163648 DOI: 10.1021/cb5000014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PLA (phospholipases A) are important mediators of cell signaling, generating bioactive fatty acids and LPLs (lysophospholipids). PLA products having different head groups can initiate vastly different types of signaling. Fluorogenic analogues of the PLs (phospholipids) PA (phosphatidic acid), PC (phosphatidylcholine), PE (phosphatidylethanolamine), and PG (phosphatidylglycerol) were synthesized as PLA substrates for rapidly determining in real time the influence of head group modifications on cell signaling both in vitro and in cells. Enzyme-assisted remodeling of the sn-2 position of the diacylglyceryl moiety with cobra venom PLA 2 and transphosphatidylation with a particular PLD (phospholipase D) were central steps in the preparation of these enzymatic probes. The resulting fluorogenic Dabcyl- and BODIPY-containing PL analogues, DBPA, DBPC, DBPE, and DBPG, were used in mixed micelle assays to determine PLA 2 kinetics. Next, the assays were used to determine the X i (50) value of a common PLA 2 inhibitor. Finally, the head group selectivities of a series of commercially available PLA 2 enzymes were readily established using the DBPLs (Dabcyl-BODIPY PLs) as substrates.
Collapse
Affiliation(s)
- Tyler M Rose
- Department of Medicinal Chemistry and Center for Cell Signaling, University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108, USA
| | | |
Collapse
|
72
|
Yan W, Jenkins CM, Han X, Mancuso DJ, Sims HF, Yang K, Gross RW. The Highly Selective Production of 2-Arachidonoyl Lysophosphatidylcholine Catalyzed by Purified Calcium-independent Phospholipase A2γ. J Biol Chem 2005; 280:26669-79. [PMID: 15908428 DOI: 10.1074/jbc.m502358200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Herein, we report the heterologous expression of the human peroxisomal 63-kDa calcium-independent phospholipase A2gamma (iPLA2gamma) isoform in Sf9 cells, purification of the N-terminal His-tagged enzyme by affinity chromatography, and the identification of its remarkable substrate selectivity that results in the highly selective generation of 2-arachidonoyl lysophosphatidylcholine. Mass spectrometric analyses demonstrated that purified iPLA2gamma hydrolyzed saturated or monounsaturated aliphatic groups readily from either the sn-1 or sn-2 positions of phospholipids. In addition, purified iPLA2gamma effectively liberated arachidonic acid from the sn-2 position of plasmenylcholine substrates. In contrast, incubation of iPLA2gamma with 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine resulted in the rapid release of palmitic acid and the selective accumulation of 2-arachidonoyl lysophosphatidylcholine (LPC), which was not metabolized further by iPLA2gamma. The putative regiospecificity of the 2-arachidonoyl LPC product was authenticated by its diagnostic fragmentation pattern during tandem mass spectrometric analysis. To identify the physiological relevance of iPLA2gamma-mediated 2-arachidonoyl LPC production utilizing naturally occurring membranes, we incubated purified rat hepatic peroxisomes with iPLA2gamma and similarly identified the selective accumulation of 2-arachidonoyl LPC. Furthermore, tandem mass spectrometric analysis demonstrated that 2-arachidonoyl LPC is a natural product in human myocardium, a tissue in which iPLA2gamma expression is robust. Because 2-arachidonoyl LPC represents a key branch point intermediate that can potentially lead to a variety of bioactive molecules in eicosanoid signaling (e.g. arachidonic acid, 2-arachidonoylglycerol), these results have uncovered a novel eicosanoid selective pathway through iPLA2gamma-mediated 2-arachidonoyl LPC production to amplify and diversify the repertoire of biologic lipid second messengers in response to cellular stimulation.
Collapse
Affiliation(s)
- Wei Yan
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | | | | | | | |
Collapse
|
73
|
Staege MS, Hutter C, Neumann I, Foja S, Hattenhorst UE, Hansen G, Afar D, Burdach SEG. DNA microarrays reveal relationship of Ewing family tumors to both endothelial and fetal neural crest-derived cells and define novel targets. Cancer Res 2005; 64:8213-21. [PMID: 15548687 DOI: 10.1158/0008-5472.can-03-4059] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ewing family tumors (EFTs) are small round blue cell tumors that show features of neuroectodermal differentiation. However, the histogenetic origin of EFTs is still a matter of debate. We used high-density DNA microarrays for the identification of EFT-specific gene expression profiles in comparison with normal tissues of diverse origin. We identified 37 genes that are up-regulated in EFTs compared with normal tissues and validated expression of these genes in EFTs by both conventional and quantitative reverse transcription-polymerase chain reaction. The expression pattern of EFT-associated genes in normal tissues indicated a high similarity between EFTs and fetal and neuronal as well as endothelial tissues and supports the concept that a primitive neural crest-derived progenitor at the transition to mesenchymal and endothelial differentiation is transformed in EFTs. EFT-associated genes could be used for molecular discrimination between EFTs and other small round blue cell tumors and clearly identified a cell line (SK-N-MC) that was initially established as neuroblastoma as being an EFT. Ectopic expression of the EFT-specific EWS-FLI1 fusion protein in human embryonic kidney (HEK293) cells was not sufficient to induce the complete EFT-specific gene expression signature, suggesting that the EFT-specific gene expression profile is not just a consequence of EWS-FLI1 expression but depends on the histogenetic background of the EFT stem cell.
Collapse
Affiliation(s)
- Martin S Staege
- Children's Cancer Research Center, Division of Pediatric Hematology and Oncology and BioCenter, Martin-Luther University Halle-Wittenberg, Halle, Germany
| | | | | | | | | | | | | | | |
Collapse
|
74
|
ISHIDA M, IMAGAWA M, SHIMIZU T, TAGUCHI R. Effective Extraction and Analysis for Lysophosphatidic Acids and Their Precursors in Human Plasma Using Electrospray Ionization Mass Spectrometry. ACTA ACUST UNITED AC 2005. [DOI: 10.5702/massspec.53.217] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
75
|
Robin P, Chouayekh S, Bole-Feysot C, Leiber D, Tanfin Z. Contribution of phospholipase D in endothelin-1-mediated extracellular signal-regulated kinase activation and proliferation in rat uterine leiomyoma cells. Biol Reprod 2004; 72:69-77. [PMID: 15355882 DOI: 10.1095/biolreprod.104.033852] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Endothelin (ET)-1 is a mitogenic factor in numerous cell types, including rat myometrial cells. In the present study, we investigated the potential role of ET-1 in the proliferation of tumoral uterine smooth muscle cells (ELT-3 cells). We found that ET-1 exerted a more potent mitogenic effect in ELT-3 cells than in normal myometrial cells, as indicated by the increase in [3H]thymidine incorporation, cell number, and bromodeoxyuridine incorporation. The ET-1 was more efficient than platelet-derived growth factor and epidermal growth factor to stimulate proliferation. The ET-1-mediated cell proliferation was inhibited in the presence of U0126, a specific inhibitor of (mitogen-activated protein kinase ERK kinase), indicating that extracellular signal-regulated kinase (ERK) activation is involved. Additionally, ET-1 induced the activation of phospholipase (PL) D, leading to the synthesis of phosphatidic acid (PA). The ET-1-induced activation of PLD was twofold higher in ELT-3 cells compared to that in normal cells. The two cell types expressed mRNA for PLD1a and PLD2, whereas PLD1b was expressed only in ELT-3 cells. The exposure of cells to butan-1-ol reduced ET-1-mediated production of PA by PLD and partially inhibited ERK activation and DNA synthesis. Addition of exogenous PLD or PA in the medium reproduced the effect of ET-1 on ERK activation and cell proliferation. Collectively, these data indicate that ET-1 is a potent mitogenic factor in ELT-3 cells via a signaling pathway involving a PLD-dependent activation of ERK. This highlights the potential role of ET-1 in the development of uterine leiomyoma, and it reinforces the role of PLD in tumor growth.
Collapse
Affiliation(s)
- Philippe Robin
- Laboratoire de signalisation et régulations cellulaires, IBBMC, CNRS UMR 8619, Bat 430 Université Paris Sud, 91 405 Orsay Cedex, France
| | | | | | | | | |
Collapse
|
76
|
Tanaka M, Kishi Y, Takanezawa Y, Kakehi Y, Aoki J, Arai H. Prostatic acid phosphatase degrades lysophosphatidic acid in seminal plasma. FEBS Lett 2004; 571:197-204. [PMID: 15280042 DOI: 10.1016/j.febslet.2004.06.083] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Accepted: 06/28/2004] [Indexed: 11/30/2022]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator with multiple biological activities and is detected in various biological fluids, including human seminal plasma. Due to its cell proliferation stimulatory and anti-apoptotic activities, LPA has been implicated in the progression of some cancers such as ovarian cancer and prostate cancer. Here, we show that prostatic acid phosphatase, which is a non-specific phosphatase and which has been implicated in the progression of prostate cancer, inactivates LPA in human seminal plasma. Human seminal plasma contains both an LPA-synthetic enzyme, lysoPLD, which converts lysophospholipids to LPA and is responsible for LPA production in serum, and its major substrate, lysophosphatidylcholine. In serum, LPA accumulated during incubation at 37 degrees C. However, in seminal plasma, LPA did not accumulate. This discrepancy is explained by the presence of a strong LPA-degrading activity. Incubation of LPA with seminal plasma resulted in the disappearance of LPA and an accompanying accumulation of monoglyceride showing that LPA is degraded by phosphatase activity present in the seminal plasma. When seminal plasma was incubated in the presence of a phosphatase inhibitor, sodium orthovanadate, LPA accumulated, indicating that LPA is produced and degraded in the fluid. Biochemical characterization of the LPA-phosphatase activity identified two phosphatase activities in human seminal plasma. By Western blotting analysis in combination with several column chromatographies, the major activity was revealed to be identical to prostatic acid phosphatase. The present study demonstrates active LPA metabolism in seminal plasma and indicates the possible role of LPA signaling in male sexual organs including prostate cancer.
Collapse
Affiliation(s)
- Masayuki Tanaka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | | | |
Collapse
|
77
|
Moolenaar WH, van Meeteren LA, Giepmans BNG. The ins and outs of lysophosphatidic acid signaling. Bioessays 2004; 26:870-81. [PMID: 15273989 DOI: 10.1002/bies.20081] [Citation(s) in RCA: 445] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator with a wide variety of biological actions, particularly as an inducer of cell proliferation, migration and survival. LPA binds to specific G-protein-coupled receptors and thereby activates multiple signal transduction pathways, including those initiated by the small GTPases Ras, Rho, and Rac. LPA signaling has been implicated in such diverse processes as wound healing, brain development, vascular remodeling and tumor progression. Knowledge of precisely how and where LPA is produced has long proved elusive. Excitingly, it has recently been discovered that LPA is generated from precursors by 'autotaxin', a once enigmatic exo-phosphodiesterase implicated in tumor cell motility. Exogenous phospholipases D can also produce LPA, which may contribute to their toxicity. Here we review recent progress in our understanding of LPA bioactivity, signaling and synthesis.
Collapse
Affiliation(s)
- Wouter H Moolenaar
- Division of Cellular Biochemistry and Center for Biomedical Genetics, The Netherlands Cancer Institute, Plesmanlaan, Amsterdam, The Netherlands.
| | | | | |
Collapse
|
78
|
Tokumura A. Metabolic pathways and physiological and pathological significances of lysolipid phosphate mediators. J Cell Biochem 2004; 92:869-81. [PMID: 15258912 DOI: 10.1002/jcb.20147] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Lysophosphatidic acid and sphingosine 1-phosphate are structurally simple and physiologically very important lysophospholipids. Because they possess distinct structural backbones (glycerol and sphingosine, respectively), there are different metabolic pathways for their intracellular production. Recently, several key enzymes that produce or degrade these lysolipid phosphate mediators extracellularly have been characterized. This review focuses on the physiological and pathophysiological significances of the extracellular metabolic pathways involving recently characterized exo-type lysophospholipase D, ecto-type phospholipase A, and ecto-type lipid phosphate phosphatase.
Collapse
Affiliation(s)
- Akira Tokumura
- Faculty of Pharmaceutical Sciences, The University of Tokushima, Tokushima 770-8505, Japan.
| |
Collapse
|