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Woclawek-Potocka I, Komiyama J, Saulnier-Blache JS, Brzezicka E, Bah MM, Okuda K, Skarzynski DJ. Lysophosphatic acid modulates prostaglandin secretion in the bovine uterus. Reproduction 2008; 137:95-105. [PMID: 18829944 DOI: 10.1530/rep-08-0209] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lysophosphatidic acid (LPA) modulates prostaglandin (PG) synthesis via LPA receptor 3 (LPAR3) in the murine endometrium. The lack of functional LPAR3 in mice may lead to embryo mortality. In the present study, we examined the role of LPA in the bovine uterus. We confirmed that LPA is locally produced and released from the bovine endometrium. Moreover, there are enzymes involved in LPA synthesis (phospholipase (PL) D(2) and PLA2G1B) in the bovine endometrium during estrous cycle and early pregnancy. Expression of the receptor for LPA (LPAR1) was positively correlated with the expression of PGE(2) synthase (PGES) and negatively correlated with the expression of PGF(2alpha) synthase (aldose reductase with 20 alpha-hydroxysteroid dehydrogenase activity - PGFS) during early pregnancy. In vivo LPA induced P4 and PGE(2) secretion was inhibited by LPAR1 antagonist (Ki16425). The overall results indicate that LPA is locally produced and released from the bovine endometrium. Moreover, LPAR1 gene expression in the endometrium during the estrous cycle and early pregnancy indicates that LPA may play autocrine and/or paracrine roles in the bovine uterus. LPAR1 gene expression is positively correlated with the expression of the enzyme responsible for luteotropic PGE(2) production (PGES) in endometrium. In cow, LPA stimulates P4 and PGE(2) secretion. Thus, LPA in the bovine reproductive tract may indirectly (via endometrium) or directly support corpus luteum action via the increase of P4 synthesis and the increase of PGE(2)/PGF(2)(alpha) ratio. It suggests that LPA may serve as an important factor in the maintenance of early pregnancy in cow.
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Affiliation(s)
- Izabela Woclawek-Potocka
- Department of Reproductive Immunology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland
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Effects of synthetic lysophosphatidylcholines on suspension cultures of the Chinese hamster ovary DG44 cells in protein-free media. BIOTECHNOL BIOPROC E 2008. [DOI: 10.1007/s12257-008-0148-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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103
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Xu YJ, Tappia PS, Goyal RK, Dhalla NS. Mechanisms of the lysophosphatidic acid-induced increase in [Ca(2+)](i) in skeletal muscle cells. J Cell Mol Med 2008; 12:942-54. [PMID: 18494935 PMCID: PMC4401138 DOI: 10.1111/j.1582-4934.2008.00139.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although lysophosphatidic acid (LPA) is known to increase intracellularfree calcium concentration ([Ca2+]i) in different cell types, the effect of LPA on the skeletal muscle cells is not known. The present study was therefore undertaken to examine the effect of LPA on the [Ca2+]i in C2C12 cells. LPA induced a concentration and time dependent increase in [Ca2+]i, which was inhibited by VPC12249, VPC 32183 and dioctanoyl glycerol pyrophosphate, LPA1/3 receptor antagonists. Pertussis toxin, a Gi protein inhibitor, also inhibited the LPA-induced increase in [Ca2+]i. Inhibition of tyrosine kinase activities with tyrphostin A9 and genistein also prevented the increase in [Ca2+]i due to LPA. Likewise, wortmannin and LY 294002, phosphatidylinositol 3-kinase (PI3-K) inhibitors, inhibited [Ca2+]i response to LPA. The LPA effect was also attenuated by ethylene glycolbis(β-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA), an extracellular Ca2+ chelator, Ni2+ and KB-R7943, inhibitors of the Na+-Ca2+ exchanger; the receptor operated Ca2+ channel (ROC) blockers, 2-aminoethoxydiphenyl borate and SK&F 96365. However, the L-type Ca2+ channel blockers, verapamil and diltiazem; the store operated Ca2+ channel blockers, La3+ and Gd3+; a sarcoplasmic reticulum calcium pump inhibitor, thapsigargin; an inositol trisphosphate receptor antagonist, xestospongin and a phospholipase C inhibitor, U73122, did not prevent the increase [Ca2+]i due to LPA. Our data suggest that the LPA-induced increase in [Ca2+]i might occur through Gi-protein coupled LPA1/3 receptors that may be linked to tyrosine kinase and PI3-K, and may also involve the Na+-Ca2+ exchanger as well as the ROC. In addition, LPA stimulated C2C12 cell proliferation via PI3-K. Thus, LPA may be an important phospholipid in the regulation of [Ca2+]i and growth of skeletal muscle cells.
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Affiliation(s)
- Yan-Jun Xu
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
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104
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Li ZG, Yu ZC, Wang DZ, Ju WP, Zhan X, Wu QZ, Wu XJ, Cong HM, Man HH. Influence of acetylsalicylate on plasma lysophosphatidic acid level in patients with ischemic cerebral vascular diseases. Neurol Res 2008; 30:366-9. [PMID: 18544253 DOI: 10.1179/174313208x300369] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND AND PURPOSE Lysophosphatidic acid (LPA) is released from activated platelets. Acetylsalicylate (aspirin) is the most commonly used antiplatelet drug. The purpose of this study is to observe whether treatment with acetylsalicylate decreases the LPA level in patients with ischemic cerebrovascular diseases. METHODS We performed a study examining LPA level in fresh plasma in cases and controls enrolled in the LPA and Stroke Prevention Study. Level of LPA was assayed by measuring its inorganic phosphorus after separation by chromatography. RESULTS An elevated LPA level was seen in cases (n = 254) with ischemic cerebrovascular disease (3.11+/- 1.55 micromol/l) compared with 136 healthy controls (1.77 +/- 1.04 micromol/l) (p < 0.001). Administration of aspirin (100 mg q.d.) for 1 month significantly lowered LPA level in patients (n = 142) (2.41 +/- 1.03 mu mol/l) compared with that before taking acetylsalicylate (4.06 +/- 1.03 micromol/l) (p < 0.001). However, the LPA level in patients (n = 36) who stopped acetylsalicylate after taking it for 1 month was re-elevated. Before and after taking acetylsalicylate for 1 month, their LPA levels were 4.23 +/- 1.15 and 1.93 +/- 0.85 micromol/l, respectively. After 1 month withdrawal, level was 3.90 +/- 1.09 micromol/l (p < 0.001 compared that before taking acetylsalicylate). CONCLUSION Our findings support a close association between increased plasma LPA level and platelet activation. Acetylsalicylate could decrease plasma LPA levels, which may be used as a mechanism for acetylsalicylate in the prevention of ischemic stroke.
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Affiliation(s)
- Zhen-Guang Li
- Department of Neurology, Wendeng Central Hospital, Weifang Medical College, Weifang, China.
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105
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Kortlever RM, Brummelkamp TR, van Meeteren LA, Moolenaar WH, Bernards R. Suppression of the p53-dependent replicative senescence response by lysophosphatidic acid signaling. Mol Cancer Res 2008; 6:1452-60. [PMID: 18723828 DOI: 10.1158/1541-7786.mcr-08-0066] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator of a large number of biological processes, including wound healing, brain development, vascular remodeling, and tumor progression. Its role in tumor progression is probably linked to its ability to induce cell proliferation, migration, and survival. In particular, the ascites of ovarian cancers is rich in LPA and has been implicated in growth and invasion of ovarian tumor cells. 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. We report here a genetic screen with retroviral cDNA expression libraries to identify genes that allow bypass of the p53-dependent replicative senescence response in mouse neuronal cells, conditionally immortalized by a temperature-sensitive mutant of SV40 large T antigen. Using this approach, we identified the LPA receptor type 2 (LPA(2)) and the Rho-specific guanine nucleotide exchange factor Dbs as potent inducers of senescence bypass. Enhanced expression of LPA(2) or Dbs also results in senescence bypass in primary mouse embryo fibroblasts in the presence of wild-type p53, in a Rho GTPase-dependent manner. Our results reveal a novel and unexpected link between LPA signaling and the p53 tumor-suppressive pathway.
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Affiliation(s)
- Roderik M Kortlever
- Division of Molecular Carcinogenesis, Center for Cancer Genomics, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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106
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Xun Z, Kaufman TC, Clemmer DE. Proteome response to the panneural expression of human wild-type alpha-synuclein: a Drosophila model of Parkinson's disease. J Proteome Res 2008; 7:3911-21. [PMID: 18683964 DOI: 10.1021/pr800207h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The alpha-synuclein protein is associated with several neurodegenarative diseases, including Parkinson's disease (PD). In humans, only mutated forms of alpha-synuclein are linked to PD; however, panneural expression of human wild-type (WT) alpha-synuclein induces Parkinson's like-symptoms in Drosophila. Here, we report a quantitative proteomic analysis of WT alpha-synuclein transgenic flies with age-matched controls at the presymptomatic stage utilizing a global isotopic labeling strategy combined with multidimensional liquid chromatographies and tandem mass spectrometry. The analysis includes two biological replicates, in which samples are isotopically labeled in forward and reverse directions. In total, 229 proteins were quantified from assignments of at least two peptide sequences. Of these, 188 (82%) proteins were detected in both forward and reverse labeling measurements. Twelve proteins were found to be differentially expressed in response to the expression of human WT alpha-synuclein; down-regulations of larval serum protein 2 and fat body protein 1 levels were confirmed by Western blot analysis. Gene Ontology analysis indicates that the dysregulated proteins are primarily associated with cellular metabolism and signaling, suggesting potential contributions of perturbed metabolic and signaling pathways to PD. An increased level of the iron (III)-binding protein, ferritin, typically found in the brains of PD patients, is also observed in presymptomatic WT alpha-synuclein expressing animals. The observed alterations in both pathology-associated and novel proteins may shed light on the pathological roles of alpha-synuclein that may lead to the development of diagnostic strategies at the presymptomatic stage.
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Affiliation(s)
- Zhiyin Xun
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
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107
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Shin KJ, Kim YL, Lee S, Kim DK, Ahn C, Chung J, Seong JY, Hwang JI. Lysophosphatidic acid signaling through LPA receptor subtype 1 induces colony scattering of gastrointestinal cancer cells. J Cancer Res Clin Oncol 2008; 135:45-52. [PMID: 18592268 DOI: 10.1007/s00432-008-0441-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Accepted: 06/16/2008] [Indexed: 01/21/2023]
Abstract
PURPOSE Lysophosphatidic acid (LPA) is a multifunctional lipid mediator involved in triggering tumor cell invasion and metastasis, as well as malignant cell growth. LPA is also known to modulate the colony scattering of epithelial cancers, which is a prerequisite for cell invasion. However, the underlying details of how this is accomplished are not clear. Here we have investigated the roles of specific LPA receptor subtypes in cell scattering. METHODS Gastrointestinal carcinoma cell lines were examined for cell scattering activity in response to LPA, and the expression of LPA receptor subtypes was determined by RT-PCR. The effect of down regulation of each LPA receptor in DLD1 cells was determined using a shRNA-lentivirus system. In addition, the effect of overexpression of LPA receptors on cell scattering was investigated using lentivirus expression constructs. RESULTS The colonies of AGS and DLD1, but not MKN74, cells were dispersed in response to LPA. RT-PCR analysis revealed that the mRNAs of LPA1, LPA2, and LPA3 were present in AGS and DLD1 cells, but only LPA2 mRNA was detected in MKN74 cells. In DLD1 cells, the scattering activity induced by LPA was partially blocked by pretreatment with PP2 and PD98059, inhibitors of src kinase and MEK, respectively. LPA1 knockdown with shRNA decreased the degree of cell scattering induced by LPA. Knockdown of LPA2 or LPA3 had no effect on LPA-induced scattering. In addition, overexpression of LPA1 in DLD1 cells slightly decreased the response time of LPA-induced cell scattering. On the contrary, MKN74 cells expressing exogenous LPA1 did not respond to LPA by scattering. CONCLUSION These results demonstrate that LPA1 mediates LPA-stimulated cell scattering of gastrointestinal carcinomas, but that activation of other intracellular pathways, besides those contributing to ERK phosphorylation, is also necessary for cell scattering in response to LPA.
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Affiliation(s)
- Kum-Joo Shin
- Department of Biochemistry, College of Medicine and Cancer Research Institute, Seoul National University, Seoul, 110-799, Republic of Korea
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108
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Lv G, Sun Z, Li N, Li S, Zhang Y, Xie Y, Yu W, Wang W, Ma X. Design a chemically defined/medically approved medium for cell transplantation according to the metabolic characteristics of microencapsulated cells and the process of encapsulation. Biochem Eng J 2008. [DOI: 10.1016/j.bej.2007.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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109
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Kirchner M, Higgins DE. Inhibition of ROCK activity allows InlF-mediated invasion and increased virulence of Listeria monocytogenes. Mol Microbiol 2008; 68:749-67. [PMID: 18331468 DOI: 10.1111/j.1365-2958.2008.06188.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Listeria monocytogenes is an intracellular bacterial pathogen that causes life-threatening disease. The mechanisms used by L. monocytogenes to invade non-professional phagocytic cells are not fully understood. In addition to the requirement of bacterial determinants, host cell conditions profoundly influence infection. Here, we have shown that inhibition of the RhoA/ROCK pathway by pharmacological inhibitors or RNA interference results in increased L. monocytogenes invasion of murine fibroblasts and hepatocytes. InlF, a member of the internalin multigene family with no known function, was identified as a L. monocytogenes-specific factor mediating increased host cell binding and entry. Conversely, activation of RhoA/ROCK activity resulted in decreased L. monocytogenes adhesion and invasion. Furthermore, virulence of wild-type bacteria during infection of mice was significantly increased upon inhibition of ROCK activity, whereas colonization and virulence of an inlF deletion mutant was not affected, thus supporting a role for InlF as a functional virulence determinant in vivo under specific conditions. In addition, inhibition of ROCK activity in human-derived cells enhanced either bacterial adhesion or adhesion and entry in an InlF-independent manner, further suggesting a host species or cell type-specific role for InlF and that additional bacterial determinants are involved in mediating ROCK-regulated invasion of human cells.
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Affiliation(s)
- Marieluise Kirchner
- Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood, Boston, MA 02115, USA
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110
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Chen SU, Chou CH, Lee H, Ho CH, Lin CW, Yang YS. Lysophosphatidic acid up-regulates expression of interleukin-8 and -6 in granulosa-lutein cells through its receptors and nuclear factor-kappaB dependent pathways: implications for angiogenesis of corpus luteum and ovarian hyperstimulation syndrome. J Clin Endocrinol Metab 2008; 93:935-43. [PMID: 18171700 DOI: 10.1210/jc.2007-1512] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Lysophosphatidic acid (LPA) was found at significant amounts in follicular fluid of preovulatory follicle. The lysophospholipase D activity of serum from women receiving ovarian stimulation was higher than women with natural cycles. Angiogenic cytokines, including IL-6, IL-8, and vascular endothelial growth factor, increased in plasma and ascites of patients with ovarian hyperstimulation syndrome. The role of LPA in ovarian follicles is unclear. OBJECTIVE Our objective was to investigate the expression of LPA receptors and function of LPA in granulosa-lutein cells. DESIGN Granulosa-lutein cells were obtained from women undergoing in vitro fertilization. We examined the expression of LPA receptors using RT-PCR. The effects of LPA on the expression of IL-6, IL-8, and vascular endothelial growth factor were examined. Signal pathways of LPA were delineated. The functions of secretory angiogenic factors were tested using human umbilical vein endothelial cells. RESULTS The LPA1, LPA2, and LPA3 receptors' mRNA was identified in granulosa-lutein cells. LPA enhanced IL-8 and IL-6 expressions in a dose- and time-dependent manner. LPA functioned via LPA receptors, Gi protein, MAPK/ERK, p38, phosphatidylinositol 3-kinase/Akt, and nuclear factor-kappaB, and transactivation of epidermal growth factor receptor. LPA induced IL-8 and IL-6 through different pathways. LPA-induced IL-8 and IL-6 increased permeability of human umbilical vein endothelial cell monolayer. CONCLUSIONS LPA induces IL-8 and IL-6 expressions through LPA receptors and nuclear factor-kappaB dependent pathways in granulosa-lutein cells. The LPA in preovulatory follicles may play a role in the angiogenesis of corpus luteum. Large amounts of LPA-induced IL-8 and IL-6 from multiple corpora luteae of stimulated ovaries may be one of the pathophysiological causes of ovarian hyperstimulation syndrome.
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Affiliation(s)
- Shee-Uan Chen
- Department of Obstetrics and Gynecology, National Taiwan University Hospital, No. 7 Chung-Shan South Road, Taipei, Taiwan
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111
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Kienesberger PC, Lass A, Preiss-Landl K, Wolinski H, Kohlwein SD, Zimmermann R, Zechner R. Identification of an insulin-regulated lysophospholipase with homology to neuropathy target esterase. J Biol Chem 2007; 283:5908-17. [PMID: 18086666 DOI: 10.1074/jbc.m709598200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuropathy target esterase (NTE) is a member of the family of patatin domain-containing proteins and exhibits phospholipase activity in brain and cultured cells. NTE was originally identified as target enzyme for organophosphorus compounds that cause a delayed paralyzing syndrome with degeneration of nerve axons. Here we show that the structurally related murine protein NTE-related esterase (NRE) is a potent lysophospholipase. The enzyme efficiently hydrolyzes sn-1 esters in lysophosphatidylcholine and lysophosphatidic acid. No lipase activity was observed when triacylglycerols, cholesteryl esters, retinyl esters, phosphatidylcholine, or monoacylglycerol were used as substrates. Although NTE is predominantly expressed in the nervous system, we found the highest NRE mRNA levels in testes, skeletal muscle, cardiac muscle, and adipose tissue. Induction of NRE mRNA concentrations in these tissues during fasting suggested a nutritional regulation of enzyme expression and, in accordance with this observation, insulin reduced NRE mRNA levels in a dose-dependent manner in 3T3-L1 adipocytes. A green fluorescent protein-NRE fusion protein colocalized to the endoplasmic reticulum and lipid droplets. Thus, NRE is a previously unrecognized ER- and lipid droplet-associated lysophospholipase. Regulation of enzyme expression by the nutritional status and insulin suggests a role of NRE in the catabolism of lipid precursors and/or mediators that affect energy metabolism in mammals.
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112
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Kamińska K, Wasielak M, Bogacka I, Blitek M, Bogacki M. Quantitative expression of lysophosphatidic acid receptor 3 gene in porcine endometrium during the periimplantation period and estrous cycle. Prostaglandins Other Lipid Mediat 2007; 85:26-32. [PMID: 18024221 DOI: 10.1016/j.prostaglandins.2007.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 10/03/2007] [Accepted: 10/03/2007] [Indexed: 11/19/2022]
Abstract
Lysophosphatidic acid (LPA) belongs to the group of lipid messengers, which act via lysophosphatidic acid receptor 3 coupled to G-proteins. The participation of LPA3 in reproductive biology was revealed in mice and has not been studied in gilts. The present study was performed to evaluate the gene expression of LPA3 by a quantitative real-time PCR technique in the endometrium during different stages of pregnancy (days 6-30) and corresponding days of the estrous cycle (days 2-20) as well as in periimplantation period in pigs with surgically detached uterine horns. Based on the most conserved segments of human and rodent LPA3 we obtained a product containing 619bp (GenBank: EF137953), which exhibited high homology with human and rodents sequences. The highest transcript level was noted on days 10-12 of gestation in comparison to remaining periods and during pregnancy on days: 6-7, 8-9, 10-12 and 13-14 in comparison with the corresponding days of the estrous cycle. Higher mRNA level was noted in the horn containing embryos compared to the contralateral horn, where embryos did not develop. The results imply the important role of receptor LPA3 during early pregnancy.
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Affiliation(s)
- Katarzyna Kamińska
- Institute of Animal Reproduction and Food Research of Polish Academy of Science, Tuwima 10, 10-747 Olsztyn, Poland
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Mori K, Kitayama J, Aoki J, Kishi Y, Shida D, Yamashita H, Arai H, Nagawa H. Submucosal connective tissue-type mast cells contribute to the production of lysophosphatidic acid (LPA) in the gastrointestinal tract through the secretion of autotaxin (ATX)/lysophospholipase D (lysoPLD). Virchows Arch 2007; 451:47-56. [PMID: 17554559 DOI: 10.1007/s00428-007-0425-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 04/11/2007] [Accepted: 04/25/2007] [Indexed: 01/21/2023]
Abstract
Lysophosphatidic acid (LPA) is involved in a broad spectrum of biological activities, including wound healing and cancer metastasis. Autotaxin (ATX), originally isolated from a melanoma supernatant as a tumor cell motility-stimulating factor, has been shown to be molecularly identical to lysophospholipase D (lysoPLD), which is the main enzyme in the production of LPA. Although ATX/lysoPLD is known to be widely expressed in normal human tissues, the exact distribution of ATX-producing cells has not been fully investigated. In this study, we evaluated ATX/lysoPLD expression by immunohistochemical staining using a rat anti-ATX mAb in the human gastrointestinal tract and found that submucosal mast cells (MC) highly expressed this enzyme. This was confirmed by immunofluorescent double staining using mAbs to tryptase and chymase. Then, we isolated MC from human gastric tissue by an immunomagnetic method using CD117-microbeads and showed that a subpopulation of CD203c-positive MC showed positive staining for intracellular ATX/lysoPLD on flowcytometry. This was confirmed by Western blotting of the isolated cells. Moreover, a significant level of ATX/lysoPLD release could be detected in the culture supernatants of human MC by Western blot analysis. Our data suggest that submucosal MC play significant roles in various aspects of pathophysiology in the gastrointestinal tract by locally providing bioactive LPA through the production of ATX/lysoPLD.
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Affiliation(s)
- Ken Mori
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Wang P, Wu X, Chen W, Liu J, Wang X. The lysophosphatidic acid (LPA) receptors their expression and significance in epithelial ovarian neoplasms. Gynecol Oncol 2007; 104:714-20. [PMID: 17204312 DOI: 10.1016/j.ygyno.2006.10.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2006] [Revised: 09/08/2006] [Accepted: 10/02/2006] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To investigate the lysophosphatidic acid (LPA) receptors expression situation and their biological significance in human ovarian cancer cell lines and in human epithelial ovarian neoplasms. METHODS The reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were employed to measure the expression levels of LPA(1), LPA(2) and LPA(3) mRNA, LPA(2) and LPA(3) protein expression in cultured human ovarian cancer cell lines (3AO, SKOV3 and OVCAR3) and in human epithelial ovarian neoplasms. The immunocytochemical method was used to detect LPA(2) and LPA(3) protein expression in cultured human ovarian cancer cell lines. RESULTS RT-PCR revealed that all ovarian cancer cell lines expressed LPA(1), LPA(2) and LPA(3) mRNA. The positive rates (100%; 86.4%; 88.2%) of LPA(1) mRNA in normal ovarian tissue, benign tumor and ovarian cancer were no significant difference (p>0.05). The expression level of LPA(1) mRNA was significantly higher in normal ovarian tissue compared with that in benign tumor and in ovarian cancer tissue (p<0.01). LPA(1) expression level was no significant difference in both benign tumor and ovarian cancer tissue (p>0.05). LPA(2) mRNA-positive rates (92.6%) and expression level were significantly higher in ovarian cancer compared with that in benign tumor (31.8%) and in normal ovarian tissue (31.3%) (p<0.01); LPA(2) mRNA-positive rates and expression level were no significant difference in both benign tumor and normal ovarian tissue (p>0.05). LPA(3) mRNA-positive rates (92.6%) and expression level were significantly higher in ovarian cancer compared with that in benign tumor (31.8%) and in normal ovarian tissue (31.3%) (p<0.01), LPA(3) mRNA-positive rates and expression level were no significant difference in both benign tumor and normal ovarian tissue (p>0.05). LPA(1) mRNA expression level was significantly decreased compared with that of LPA(2) and LPA(3) in ovarian cancer (p<0.01); Western blotting clearly revealed that all ovarian cancer cell lines showed LPA(2) and LPA(3) protein. The positive rates and expression level of LPA(2) and LPA(3) protein were significantly increased in ovarian cancer (92.6%; 92.6%) compared with that in benign tumor (45.5%; 45.5%) and that in normal ovarian tissue (43.8%; 43.8%) (p<0.01); LPA(2) and LPA(3) protein-positive rates and expression level were no significant difference in both benign tumor and normal ovarian tissue (p>0.05). Correlation of clinicopathological parameters showed that LPA receptors mRNA and protein expression were associated with FIGO stage and histological grade, except pathologic types and age. The mRNA and protein expression of LPA(2) and LPA(3) in stages III and IV was significantly higher than that in stages I and II epithelial ovarian cancer (p<0.05). The mRNA and protein expression of pathologic grade G(3) was significantly higher compared with grade G(1) (p<0.05). CONCLUSION LPA(1), LPA(2) and LPA(3) mRNA and protein expressed widely in human epithelial ovarian neoplasms. LPA(2) and LPA(3) may be involved in the development and progression of human ovarian cancer. There was a significant correlation between LPA(2), LPA(3) and invasion and metastasis of epithelial ovarian cancer. LPA(2) and LPA(3) may be a prognostic indicator in patients with epithelial ovarian cancer.
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Affiliation(s)
- Ping Wang
- Department of Obstetrics and Gynecology, Fourth Affiliated Hospital, Hebei Medical University, Shijiazhuang, 050011, China
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Lee CW, Rivera R, Dubin AE, Chun J. LPA(4)/GPR23 is a lysophosphatidic acid (LPA) receptor utilizing G(s)-, G(q)/G(i)-mediated calcium signaling and G(12/13)-mediated Rho activation. J Biol Chem 2006; 282:4310-4317. [PMID: 17166850 DOI: 10.1074/jbc.m610826200] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a bioactive lysophospholipid that signals through G protein-coupled receptors (GPCRs) to produce a range of biological responses. A recently reported fourth receptor, LPA(4)/GPR23, was notable for its low homology to the previously identified receptors LPA(1-3) and for its ability to increase intracellular concentrations of cAMP and calcium. However, the signaling pathways leading to LPA(4)-mediated induction of cAMP and calcium levels have not been reported. Using epitope-tagged LPA(4), pharmacological intervention, and G protein mini-genes, we provide independent confirmatory evidence that supports LPA(4) as a fourth LPA receptor, including LPA concentration-dependent responses and specific membrane binding. Importantly, we further demonstrate new LPA-dependent activities of LPA(4) that include the following: receptor internalization; G(12/13)- and Rho-mediated neurite retraction and stress fiber formation; G(q) protein and pertussis toxin-sensitive calcium mobilization and activation of a nonselective cation conductance; and cAMP increases mediated by G(s). The receptor is broadly expressed in embryonic tissues, including brain, as determined by Northern blot and reverse transcription-PCR analysis. Adult tissues have increased expression in skin, heart, and to a lesser extent, thymus. These data confirm the identification and extend the functionality of LPA(4) as an LPA receptor, bringing the number of independently verified LPA receptors to five, with both overlapping and distinct signaling properties and tissue expression.
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MESH Headings
- Adult
- Animals
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Cell Line, Tumor
- Cyclic AMP/genetics
- Cyclic AMP/metabolism
- Dose-Response Relationship, Drug
- Embryo, Mammalian/metabolism
- Enzyme Activation
- GTP-Binding Protein alpha Subunits, G12-G13/genetics
- GTP-Binding Protein alpha Subunits, G12-G13/metabolism
- GTP-Binding Protein alpha Subunits, G12-G13/physiology
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/genetics
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- GTP-Binding Protein alpha Subunits, Gs/genetics
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- GTP-Binding Proteins/genetics
- GTP-Binding Proteins/metabolism
- Gene Expression Regulation/physiology
- Humans
- Lysophospholipids/metabolism
- Lysophospholipids/pharmacology
- Mice
- Neurites/metabolism
- Organ Specificity/physiology
- Receptors, Lysophosphatidic Acid/genetics
- Receptors, Lysophosphatidic Acid/metabolism
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Stress Fibers/genetics
- Stress Fibers/metabolism
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
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Affiliation(s)
- Chang-Wook Lee
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037
| | - Richard Rivera
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037
| | - Adrienne E Dubin
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037
| | - Jerold Chun
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037.
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116
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Lin CI, Chen CN, Chen JH, Lee H. Lysophospholipids increase IL-8 and MCP-1 expressions in human umbilical cord vein endothelial cells through an IL-1-dependent mechanism. J Cell Biochem 2006; 99:1216-32. [PMID: 16795034 DOI: 10.1002/jcb.20963] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are both low-molecular-weight lysophospholipid (LPL) ligands which are recognized by the Edg family of G protein-coupled receptors (GPCRs). In endothelial cells, these two ligands activate Edg receptors resulting in cell proliferation and cell migration. Interleukin-8 (IL-8) is a C-X-C chemokine and acts as a chemoattractant of neutrophils, whereas monocyte chemoattractant protein-1 (MCP-1) is a C-C chemokine and functions mainly as a chemoattractant of monocytes/macrophages. Both factors are secreted from endothelial cells and have been implicated in the processes leading to atherosclerosis. We examined the effects of LPLs on the expression of IL-8 and MCP-1, key regulators of leukocyte recruitment in human umbilical cord vein endothelial cells (HUVECs). Work illustrated in this article showed that LPA and S1P enhanced IL-8 and MCP-1 mRNA expressions, and protein secretions in dose- and time-dependent fashions. Maximal mRNA expression appeared at 16 hr post-ligand treatment. Using prior treatments with chemical inhibitors, LPLs enhanced IL-8 and MCP-1 expressions through a Gi-, Rho-, and NFkappaB-dependent mechanism. In a chemotaxis assay system, LPL treatments of endothelial cells enhanced monocyte recruitment through upregulating IL-8 and MCP-1 protein secretions. Pre-incubation with AF12198, an IL-1 receptor antagonist or IL-1 functional blocking antibody both suppressed the enhanced effects elicited by LPLs of IL-8 and MCP-1 mRNA expressions in HUVECs. These results suggest that LPLs released by activated platelets might enhance the IL-8- and MCP-1-dependent chemoattraction of monocytes toward the endothelium through an IL-1-dependent mechanism, which may play an important role in facilitating wound-healing and inflammation processes.
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Affiliation(s)
- Chi Iou Lin
- Institute of Zoology, National Taiwan University, Taipei, Taiwan
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117
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Fisher KE, Pop A, Koh W, Anthis NJ, Saunders WB, Davis GE. Tumor cell invasion of collagen matrices requires coordinate lipid agonist-induced G-protein and membrane-type matrix metalloproteinase-1-dependent signaling. Mol Cancer 2006; 5:69. [PMID: 17156449 PMCID: PMC1762019 DOI: 10.1186/1476-4598-5-69] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 12/08/2006] [Indexed: 12/02/2022] Open
Abstract
Background Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are bioactive lipid signaling molecules implicated in tumor dissemination. Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a membrane-tethered collagenase thought to be involved in tumor invasion via extracellular matrix degradation. In this study, we investigated the molecular requirements for LPA- and S1P-regulated tumor cell migration in two dimensions (2D) and invasion of three-dimensional (3D) collagen matrices and, in particular, evaluated the role of MT1-MMP in this process. Results LPA stimulated while S1P inhibited migration of most tumor lines in Boyden chamber assays. Conversely, HT1080 fibrosarcoma cells migrated in response to both lipids. HT1080 cells also markedly invaded 3D collagen matrices (~700 μm over 48 hours) in response to either lipid. siRNA targeting of LPA1 and Rac1, or S1P1, Rac1, and Cdc42 specifically inhibited LPA- or S1P-induced HT1080 invasion, respectively. Analysis of LPA-induced HT1080 motility on 2D substrates vs. 3D matrices revealed that synthetic MMP inhibitors markedly reduced the distance (~125 μm vs. ~45 μm) and velocity of invasion (~0.09 μm/min vs. ~0.03 μm/min) only when cells navigated 3D matrices signifying a role for MMPs exclusively in invasion. Additionally, tissue inhibitors of metalloproteinases (TIMPs)-2, -3, and -4, but not TIMP-1, blocked lipid agonist-induced invasion indicating a role for membrane-type (MT)-MMPs. Furthermore, MT1-MMP expression in several tumor lines directly correlated with LPA-induced invasion. HEK293s, which neither express MT1-MMP nor invade in the presence of LPA, were transfected with MT1-MMP cDNA, and subsequently invaded in response to LPA. When HT1080 cells were seeded on top of or within collagen matrices, siRNA targeting of MT1-MMP, but not other MMPs, inhibited lipid agonist-induced invasion establishing a requisite role for MT1-MMP in this process. Conclusion LPA is a fundamental regulator of MT1-MMP-dependent tumor cell invasion of 3D collagen matrices. In contrast, S1P appears to act as an inhibitory stimulus in most cases, while stimulating only select tumor lines. MT1-MMP is required only when tumor cells navigate 3D barriers and not when cells migrate on 2D substrata. We demonstrate that tumor cells require coordinate regulation of LPA/S1P receptors and Rho GTPases to migrate, and additionally, require MT1-MMP in order to invade collagen matrices during neoplastic progression.
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Affiliation(s)
- Kevin E Fisher
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Andreia Pop
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
| | - Wonshill Koh
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Nicholas J Anthis
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
| | - W Brian Saunders
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
| | - George E Davis
- Department of Pathology and Laboratory Medicine, Texas A&M University System Health Science Center, College Station, TX 77843, USA
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
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118
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Savitz SI, Dhallu MS, Malhotra S, Mammis A, Ocava LC, Rosenbaum PS, Rosenbaum DM. EDG receptors as a potential therapeutic target in retinal ischemia-reperfusion injury. Brain Res 2006; 1118:168-75. [PMID: 17026968 DOI: 10.1016/j.brainres.2006.05.060] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Revised: 05/17/2006] [Accepted: 05/19/2006] [Indexed: 11/21/2022]
Abstract
LPA (lysophosphatidic acid) specific endothelial differentiation gene (EDG) receptors have been implicated in various anti-apoptotic pathways. Ischemia of the brain and retina causes neuronal apoptosis, which raises the possibility that EDG receptors participate in anti-apoptotic signaling in ischemic injury. We examined the expression of EDG receptors in a model of retinal ischemia-reperfusion injury and also tested LXR-1035, a novel analogue of LPA, in the rat following global retinal ischemic injury. Rats were subjected to 45 or 60 min of raised intraocular pressure. Animals were sacrificed at 24 h post-ischemia and retinal tissue was stained for EDG receptors. In separate experiments, animals were randomized to receive LXR or saline vehicle by intravitreal injection 24 h prior to ischemia. The degree of retinal damage was assessed morphologically by measuring the thickness of the inner retinal layers as well as functionally by electroretinography (ERG). We found that the normal retina has a baseline expression of the LPA receptors, EDG-2 and EDG-4, which are significantly upregulated in the inner layers in response to ischemia. Animals pretreated with LXR-1035 had dose-dependent, significant reductions in histopathologic damage and significant improvement in functional deficits compared with corresponding vehicle-controls, after 45 and 60 min of ischemia. These results suggest that LPA receptor signaling may play an important role in neuroprotection in retinal ischemia-reperfusion injury.
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Affiliation(s)
- Sean I Savitz
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, USA.
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119
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Guo R, Kasbohm EA, Arora P, Sample CJ, Baban B, Sud N, Sivashanmugam P, Moniri NH, Daaka Y. Expression and function of lysophosphatidic acid LPA1 receptor in prostate cancer cells. Endocrinology 2006; 147:4883-92. [PMID: 16809448 DOI: 10.1210/en.2005-1635] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The bioactive phospholipid lysophosphatidic acid (LPA) promotes cell proliferation, survival, and migration by acting on cognate G protein-coupled receptors named LPA(1), LPA(2), and LPA(3). We profiled gene expression of LPA receptors in androgen-dependent and androgen-insensitive prostate cancer cells and found that LPA(1) gene is differentially expressed in androgen-insensitive and LPA-responsive but not androgen-dependent and LPA-resistant cells. In human prostate specimens, expression of LPA(1) gene was significantly higher in the cancer compared with the benign tissues. The androgen-dependent LNCaP cells do not express LPA(1) and do not proliferate in response to LPA stimulation, implying LPA(1) transduces cell growth signals. Accordingly, stable expression of LPA(1) in LNCaP cells rendered them responsive to LPA-induced cell proliferation and decreased their doubling time in serum. Implantation of LNCaP-LPA(1) cells resulted in increased rate of tumor growth in animals compared with those tumors that developed from the wild-type cells. Growth of LNCaP cells depends on androgen receptor activation, and we show that LPA(1) transduces Galphai-dependent signals to promote nuclear localization of androgen receptor and cell proliferation. In addition, treatment with bicalutamide inhibited LPA-induced cell cycle progression and proliferation of LNCaP-LPA(1) cells. These results suggest the possible utility of LPA(1) as a drug target to interfere with progression of prostate cancer.
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MESH Headings
- Blotting, Northern
- Cell Cycle/physiology
- Cell Line, Tumor
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cell Nucleus/metabolism
- Cell Proliferation
- DNA, Neoplasm/biosynthesis
- DNA, Neoplasm/genetics
- Humans
- In Situ Hybridization
- Male
- Microscopy, Fluorescence
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- RNA, Neoplasm/biosynthesis
- RNA, Neoplasm/genetics
- Receptors, Androgen/genetics
- Receptors, Lysophosphatidic Acid/biosynthesis
- Receptors, Lysophosphatidic Acid/genetics
- Receptors, Lysophosphatidic Acid/metabolism
- Signal Transduction/physiology
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Affiliation(s)
- Rishu Guo
- Department of Surgery, Duke University of Medical Center, North Carolina 27710, USA
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120
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Martinez Agosto JA, McCabe ER. Conserved family of glycerol kinase loci in Drosophila melanogaster. Mol Genet Metab 2006; 88:334-45. [PMID: 16545593 PMCID: PMC2807631 DOI: 10.1016/j.ymgme.2006.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2006] [Accepted: 01/10/2006] [Indexed: 10/24/2022]
Abstract
Glycerol kinase (GK) is an enzyme that catalyzes the formation of glycerol 3-phosphate from ATP and glycerol, the rate-limiting step in glycerol utilization. We analyzed the genome of the model organism Drosophila melanogaster and identified five GK orthologs, including two loci with sequence homology to the mammalian Xp21 GK protein. Using a combination of sequence analysis and evolutionary comparisons of orthologs between species, we characterized functional domains in the protein required for GK activity. Our findings include additional conserved domains that suggest novel nuclear and mitochondrial functions for glycerol kinase in apoptosis and transcriptional regulation. Investigation of GK function in Drosophila will inform us about the role of this enzyme in development and will provide us with a tool to examine genetic modifiers of human metabolic disorders.
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Affiliation(s)
- Julian A. Martinez Agosto
- Department of Pediatrics, David Geffen School of Medicine at UCLA; and Mattel Children’s Hospital at UCLA, USA
| | - Edward R.B. McCabe
- Department of Pediatrics, David Geffen School of Medicine at UCLA; and Mattel Children’s Hospital at UCLA, USA
- Department of Human Genetics, David Geffen School of Medicine at UCLA; UCLA Molecular Biology Institute; and UCLA Biomedical Engineering Interdepartmental Training Program, USA
- Corresponding author. Fax: +1 310 267 2045. (E.R.B. McCabe)
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121
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Lee CW, Rivera R, Gardell S, Dubin AE, Chun J. GPR92 as a new G12/13- and Gq-coupled lysophosphatidic acid receptor that increases cAMP, LPA5. J Biol Chem 2006; 281:23589-97. [PMID: 16774927 DOI: 10.1074/jbc.m603670200] [Citation(s) in RCA: 362] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The signaling effects of lysophospholipids such as lysophosphatidic acid (LPA) are mediated by G protein-coupled receptors (GPCRs). There are currently four LPA receptors known as LPA(1-4). Genetic deletion studies have identified essential biological functions for LPA receptors in mice. However, these studies have also revealed phenotypes consistent with the existence of as yet unidentified receptors. Toward identifying new LPA receptors, we have screened collections of GPCR cDNAs using reverse transfection and cell-based assays. Here we report an interim result of one screen to identify receptors that produced LPA-dependent changes in cell shape: the orphan receptor GPR92 has properties of a new LPA receptor. Sequence analyses of human GPR92 and its mouse homolog have approximately 35% amino acid identity with LPA4/GPR23. The same cell-based approaches that were used to identify and/or characterize LPA(1-4), particularly heterologous expression in B103 cells or RH7777 cells, were utilized and compared with known LPA receptors. Retroviral-mediated expression of epitope-tagged receptors was further combined with G protein minigenes and pharmacological intervention, along with calcium imaging and whole-cell patch clamp electrophysiology. LPA-dependent receptor internalization following exposure to LPA but not related lysophospholipids was observed. Furthermore, LPA induced concentration-dependent activation of G(12/13) and G(q) and increased cAMP levels. Specific [3H]LPA binding was detected in cell membranes heterologously expressing GPR92 but not control membranes. Northern blot and reverse transcriptase-PCR studies indicated a broad low level of expression in many tissues including embryonic brain and enrichment in small intestine and sensory dorsal root ganglia, as well as embryonic stem cells. These results support GPR92 as a fifth LPA receptor, LPA5, which likely has distinct physiological functions in view of its expression pattern.
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Affiliation(s)
- Chang-Wook Lee
- Department of Molecular Biology, Helen L. Dorris Institute for Neurological and Psychiatric Disorders, The Scripps Research Institute, La Jolla, California 92037, USA
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122
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Funtikova NS, Mysyakina IS. Effect of exogenous lipids on morphogenesis of the fungus Mucor lusitanicus 12M. Microbiology (Reading) 2006. [DOI: 10.1134/s0026261706030222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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123
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Kobashi H, Yaoi T, Oda R, Okajima S, Fujiwara H, Kubo T, Fushiki S. Lysophospholipid receptors are differentially expressed in rat terminal Schwann cells, as revealed by a single cell rt-PCR and in situ hybridization. Acta Histochem Cytochem 2006; 39:55-60. [PMID: 17375210 PMCID: PMC1828080 DOI: 10.1267/ahc.06002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 03/03/2006] [Indexed: 11/22/2022] Open
Abstract
Terminal Schwann cells (TSCs) that cover motor neuron terminals, are known to play an important role in maintaining neuromuscular junctions, as well as in the repair process after nerve injury. However, the molecular characteristics of TSCs remain unknown, because of the difficulties in analyzing them due to their paucity. By using our previously reported method of selectively and efficiently collecting TSCs, we have analyzed the difference in expression patterns of lysophospholipid (LPL) receptor genes (LPA1, LPA2, LPA3, S1P1, S1P2, S1P3, S1P4, and S1P5) between TSCs and myelinating Schwann cells (MSCs). LPL, which includes lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), is the bioactive lipid that induces a myriad of cellular responses through specific members of G-protein coupled receptors for LPA. It turned out that LPA3 was expressed only in TSCs, whereas S1P1 was expressed in TSCs and skeletal muscle, but not in MSCs. Other types of LPL receptor genes, including LPA1, S1P2, S1P3, S1P4, were expressed in both types of Schwann cells. None of the LPL receptor gene family showed MSCs-specific expression.
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Affiliation(s)
- Hiroaki Kobashi
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine,Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Takeshi Yaoi
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine,Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Ryo Oda
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Seiichiro Okajima
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Hiroyoshi Fujiwara
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Toshikazu Kubo
- Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
| | - Shinji Fushiki
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine,Kawaramachi-Hirokoji, Kyoto 602–8566, Japan
- Correspondence to: Shinji Fushiki, Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602–8566, Japan. E-mail:
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124
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Ye GM, Chen C, Huang S, Han DD, Guo JH, Wan B, Yu L. Cloning and characterization a novel human 1-acyl-sn-glycerol-3-phosphate acyltransferase gene AGPAT7. ACTA ACUST UNITED AC 2006; 16:386-90. [PMID: 16243729 DOI: 10.1080/10425170500213712] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The 1-Acylglycerolphosphate acyltransferase is crucial enzyme for synthesis of glycerolipids as well as triacylglylcerol biosynthesis in eukaryotes. Six members of 1-acyl-sn-glycerol-3-phosphate acyltransferase family in human have been described, which were AGPAT1, 2, 3, 4, 5 and 6. Here we report the cloning and characterization of another novel human 1-acyl-sn-glycerol-3-phosphate acyltransferase member AGPAT7 (1-acyl-sn-glycerol-3-phosphate acyltransferase 7) gene, which was mapped to human chromosome 15q14. The AGPAT7 cDNA is 1898 bp in length, encoding a putative protein with 524 amino acid residues, which contains an acyltransferase domain in 123-234 aa. RT PCR amplification in 18 human tissues indicated that human AGPAT7 gene was widely expressed in uterus, thymus, pancreas, skeletal muscle, bladder, stomach, lung and testis. AGPAT7 protein was mainly localized to the endoplasmic reticulum (ER) in Hela cells.
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Affiliation(s)
- Guang-Ming Ye
- School of Life Sciences, Fudan University, State Key Laboratory of Genetic Engineering, Shanghai, 200433, P R China
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125
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Liebner S, Cavallaro U, Dejana E. The multiple languages of endothelial cell-to-cell communication. Arterioscler Thromb Vasc Biol 2006; 26:1431-8. [PMID: 16556854 DOI: 10.1161/01.atv.0000218510.04541.5e] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Intercellular adhesion plays a key role during development and maintenance of tissue homeostasis. Within the vascular system, cell-cell adhesion is particularly important for the correct formation, networking, and remodeling of vessels. Although in vascular endothelial cells adhesive junctions account for the integrity of the vessel wall, they are not to be considered as static molecular structures that function as intercellular glue. This becomes evident during the remodeling of the endothelium in various physiological and pathological processes, requiring highly dynamic vascular adhesion complexes. Moreover, it has recently become evident that, besides their structural functions, adhesion molecules involved in endothelial cell-cell interaction play an important role in inducing and integrating intracellular signals that, in turn, impact on several aspects of vascular cell physiology. In this review, we describe these recent findings focusing on junctional proteins at adherens and tight junctions. The role of this adhesion molecule-mediated signaling is discussed in the context of developmental and pathological angiogenesis.
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Affiliation(s)
- Stefan Liebner
- Institute of Neurology, Medical School, University of Frankfurt/Main, Germany
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126
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Jourquin J, Yang N, Kam Y, Guess C, Quaranta V. Dispersal of epithelial cancer cell colonies by lysophosphatidic acid (LPA). J Cell Physiol 2006; 206:337-46. [PMID: 16110477 DOI: 10.1002/jcp.20470] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We describe a model system in which cancer cell colonies disperse into single, highly migratory cells in response to lysophosphatidic acid (LPA). Though LPA is known to stimulate chemotaxis and chemokinesis, a colony dispersal effect has not been reported, to our knowledge. Cancer colony dispersal by LPA is comprised of an ordered sequence of events: (1) stimulation of membrane ruffling and formation of lamellipodia, (2) dissolution of adherens junctions, (3) single cell migration in a mesenchymal-like morphology we term "ginkgo-leaf." The net result is dispersal of carcinoma cells from a compact colony. We analyzed these three steps using live-cell imaging and computer-assisted quantification and measured the following parameters: onset of lamellipodia formation, lamellipodia velocity, colony dispersal, trans-epithelial resistance, migrating cell number and speed. Because hepatocyte growth factor (HGF) was described as an epithelial scatter factor, we compared it to LPA in our system and found that HGF has no epithelial colony dispersal properties and that this effect is strictly related to LPA. Given its striking similarity to tumor cell budding observed in patients, we propose that LPA-colony dispersal may provide a cellular mechanism underlying cancer invasion and as such deserves further studies.
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Affiliation(s)
- Jérôme Jourquin
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6840, USA
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127
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Wu SS, Jácamo RO, Vong SK, Rozengurt E. Differential regulation of Pyk2 phosphorylation at Tyr-402 and Tyr-580 in intestinal epithelial cells: roles of calcium, Src, Rho kinase, and the cytoskeleton. Cell Signal 2006; 18:1932-40. [PMID: 16574377 DOI: 10.1016/j.cellsig.2006.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Revised: 02/21/2006] [Accepted: 02/22/2006] [Indexed: 10/25/2022]
Abstract
The calcium-dependent proline-rich tyrosine kinase Pyk2 is activated by tyrosine phosphorylation, associates with focal adhesion proteins, and has been linked to proliferative and migratory responses in a variety of mesenchymal and epithelial cell types. Full Pyk2 activation requires phosphorylation at functionally distinct sites, including autophosphorylation site Tyr-402 and catalytic domain site Tyr-580, though the mechanisms involved are unclear. The pathways mediating Pyk2 phosphorylation at Tyr-402 and Tyr-580 were therefore investigated. Both sites were rapidly and transiently phosphorylated following cell stimulation by Ang II or LPA. However, only Tyr-580 phosphorylation was rapidly enhanced by intracellular Ca(2+) release, or inhibited by Ca(2+) depletion. Conversely, Tyr-402 phosphorylation was highly sensitive to inhibition of actin stress fibers, or of Rho kinase (ROK), an upstream regulator of stress fiber assembly. Ang II also induced a delayed (30-60 min) secondary phosphorylation peak occurring at Tyr-402 alone. Unlike the homologous focal adhesion kinase (FAK), Pyk2 phosphorylation was sensitive neither to the Src inhibitor PP2, nor to truncation of its N-terminal region, which contains a putative autoinhibitory FERM domain. These results better define the mechanisms involved in Pyk2 activation, demonstrating that autophosphorylation is ROK- and stress fiber-dependent, while transphosphorylation within the kinase domain is Ca(2+)-dependent and Src-independent in intestinal epithelial cells. This contrasts with the tight sequential coupling of phosphorylation seen in FAK activation, and further underlines the differences between these closely related kinases.
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Affiliation(s)
- Steven S Wu
- Department of Pediatrics, David Geffen School of Medicine, University of California-Los Angeles, 900 Veteran Avenue, Los Angeles, CA 90095, USA.
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128
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Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are potent biologically active lipid mediators that exert a wide range of cellular effects through specific G protein-coupled receptors. To date, four LPA receptors and five S1P receptors have been identified. These receptors are expressed in a large number of tissues and cell types, allowing for a wide variety of cellular responses to lysophospholipid signaling, including cell adhesion, cell motility, cytoskeletal changes, proliferation, angiogenesis, process retraction, and cell survival. In addition, recent studies in mice show that specific lysophospholipid receptors are required for proper cardiovascular, immune, respiratory, and reproductive system development and function. Lysophospholipid receptors may also have specific roles in cancer and other diseases. This review will cover identification and expression of the lysophospholipid receptors, as well as receptor signaling properties and function. Additionally, phenotypes of mice deficient for specific lysophospholipid receptors will be discussed to demonstrate how these animals have furthered our understanding of the role lysophospholipids play in normal biology and disease.
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Affiliation(s)
- R Rivera
- The Scripps Research Institute, Department of Molecular Biology, 10550 North Torrey Pines Road, ICND-118, CA 92037, USA
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129
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Mori K, Kitayama J, Shida D, Yamashita H, Watanabe T, Nagawa H. Lysophosphatidic acid-induced effects in human colon carcinoma DLD1 cells are partially dependent on transactivation of epidermal growth factor receptor. J Surg Res 2005; 132:56-61. [PMID: 16289596 DOI: 10.1016/j.jss.2005.07.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 07/19/2005] [Accepted: 07/28/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND Lysophosphatidic acid (LPA) is a lipid mediator of diverse effects on various cells. LPA is well known to induce phosphorylation of the epidermal growth factor receptor (EGFR), which is termed transactivation, in some cell types. In this study, we investigated the contribution of EGFR transactivation in LPA-induced responses in colon cancer DLD1 cells. MATERIALS AND METHODS Immunoprecipitation was performed to investigate whether LPA induced EGFR phosphorylation. Then, we investigated LPA-induced migration and IL-8 secretion in DLD1 cells. Migration was measured in a modified Boyden chamber and IL-8 secretion was measured by ELISA. In these experiments we used an EGFR inhibitor, AG1478 or matrix metalloproteinase (MMP) inhibitor, GM6001. RESULTS Immunoprecipitation analysis revealed that LPA induced a significant level of tyrosine phosphorylation of EGFR in DLD1 cells. The LPA-induced phosphorylation of EGFR was almost completely abrogated by either AG1478 or GM6001. LPA induced significant migration and IL-8 secretion in DLD1, both of which were significantly inhibited by AG1478 or GM6001. However, the inhibitory effects were only partial (migration; 29% +/- 2%, 32 +/- 13% inhibition, IL-8 secretion; 33% +/- 1%, 26% +/- 5% inhibition, respectively). CONCLUSION These results clearly indicate that LPA acts upstream of EGFR and compensates the EGF signal and antagonism of the EGF signal cannot completely block tumor progression in colon cancer cells. Blockade of the LPA signal may have clinical significance in the treatment of colon cancer.
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Affiliation(s)
- Ken Mori
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, Tokyo 113-8655, Japan.
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130
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Neidlinger NA, Larkin SK, Bhagat A, Victorino GP, Kuypers FA. Hydrolysis of phosphatidylserine-exposing red blood cells by secretory phospholipase A2 generates lysophosphatidic acid and results in vascular dysfunction. J Biol Chem 2005; 281:775-81. [PMID: 16278219 DOI: 10.1074/jbc.m505790200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Secretory phospholipase A(2) (sPLA(2)) type IIa, elevated in inflammation, breaks down membrane phospholipids and generates arachidonic acid. We hypothesized that sPLA(2) will hydrolyze red blood cells that expose phosphatidylserine (PS) and generate lysophosphatidic acid (LPA) from phosphatidic acid that is elevated in PS-exposing red blood cells. In turn, LPA, a powerful lipid mediator, could affect vascular endothelial cell function. Although normal red blood cells were not affected by sPLA(2), at levels of sPLA(2) observed under inflammatory conditions (100 ng/ml) PS-exposing red blood cells hemolyzed and generated LPA (1.2 nM/10(8) RBC). When endothelial cell monolayers were incubated in vitro with LPA, a loss of confluence was noted. Moreover, a dose-dependent increase in hydraulic conductivity was identified in rat mesenteric venules in vivo with 5 microM LPA, and the combination of PS-exposing red blood cells with PLA(2) caused a similar increase in permeability. In the presence of N-palmitoyl L-serine phosphoric acid, a competitive inhibitor for the endothelial LPA receptor, loss of confluence in vitro and the hydraulic permeability caused by 5 microM LPA in vivo were abolished. The present study demonstrates that increased sPLA(2) activity in inflammation in the presence of cells that have lost their membrane phospholipid asymmetry can lead to LPA-mediated endothelial dysfunction and loss of vascular integrity.
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Affiliation(s)
- Nikole A Neidlinger
- Department of Surgery, University of California, San Francisco-East Bay, Oakland, 94602 USA.
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131
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Sakai K, Hayashi C, Yamaji H, Fukuda H. Use of nonionic surfactants for effective supply of phosphatidic acid in serum-free culture of Chinese hamster ovary cells. J Biosci Bioeng 2005; 92:256-61. [PMID: 16233093 DOI: 10.1263/jbb.92.256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2001] [Accepted: 06/13/2001] [Indexed: 11/17/2022]
Abstract
We have previously shown [Sakai et al., J. Biosci. Bioeng., 88, 306-309 (1999)] that exogenously supplied phosphatidic acid (PA) and lysophosphatidic acid (LPA) promoted the growth of Chinese hamster ovary (CHO) cells in serum-free culture. However, the direct addition of high concentrations of these phospholipids alone to the culture medium resulted in the formation of precipitates. We therefore examined the use of two nonionic surfactants, Tween 80 and Pluronic F-68, as a means of supplying PA more effectively to CHO cells in a serum-free culture. A clear dispersion of PA from egg yolk lecithin that could be successfully sterile-filtered was obtained by using Tween 80 or Pluronic F-68. When PA prepared with either of the surfactants was added to serum-free media, precipitation was noticeably reduced. Furthermore, the growth-promoting activity of PA was considerably enhanced by the presence of the surfactants. Since Tween 80 and Pluronic F-68 themselves possessed no growth-stimulating property, it was suggested that the enhanced growth-promoting activity results from the improved availability of PA to the cells. The use of Tween 80 with PA analogues having saturated acyl chains also accelerated cell growth, whereas these PAs showed little growth-promoting activity, due to their poor water-solubility, when added alone.
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Affiliation(s)
- K Sakai
- Division of Molecular Science, Graduate School of Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
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132
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Sakai K, Matsunaga T, Yamaji H, Fukuda H. Effects of phospholipids on growth of Chinese hamster ovary cells in serum-free media. J Biosci Bioeng 2005; 88:306-9. [PMID: 16232616 DOI: 10.1016/s1389-1723(00)80014-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/1999] [Accepted: 06/17/1999] [Indexed: 11/18/2022]
Abstract
The effects of phosphatidic acid (PA) and lysophosphatidic acid (LPA) dispersed in serum-free media on the growth of Chinese hamster ovary (CHO) cells were investigated. After cells were incubated in serum-free media supplemented with PA or LPA for 3 d, the cellular growth was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Supplementing PA from egg yolk lecithin to basal synthetic media such as alpha-MEM (minimum essential medium, alpha modification) markedly promoted the growth of CHO cells. PA from egg yolk lecithin also enhanced the cell growth in a serum-free medium containing insulin and transferring. When PA analogues with different acyl chains of C14-18 were compared, PA with unsaturated acyl chains, dioleoyl-PA (C18: 1), was most effective for stimulating the growth of CHO cells. Similar results were obtained when LPA was examined. These results suggest that PA and LPA, especially those with unsaturated acyl chains, are promising growth-promoting supplements for use as constituents in a low-protein serum-free medium.
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Affiliation(s)
- K Sakai
- Division of Molecular Science, Graduate School of Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, Hyogo 657-8501, Japan
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133
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Baldini PM, De Vito P, D'aquilio F, Vismara D, Zalfa F, Bagni C, Fiaccavento R, Di Nardo P. Role of atrial natriuretic peptide in the suppression of lysophosphatydic acid-induced rat aortic smooth muscle (RASM) cell growth. Mol Cell Biochem 2005; 272:19-28. [PMID: 16010968 DOI: 10.1007/s11010-005-4779-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [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 multiple biological functions. In the present study we investigated the possible role of atrial natriuretic peptide (ANP), a hormone affecting cardiovascular homeostasis and inducing antimitogenic effects in different cell types, on LPA-induced cell growth and reactive oxygen species (ROS) production in rat aortic smooth muscle (RASM) cells. Both LPA effects on cell growth and levels of ROS were totally abrogated by physiological concentrations of ANP, without modifying the overexpression of LPA-receptors. These effects were also affected by cell pretreatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3K). Moreover, the LPA-induced activation of Akt, a downstream target of PI3K, was completely inhibited by physiological concentrations of ANP, which were also able to inhibit p42/p44 phosphorylation. Taken together, our data suggest that PI3K may represent an important step in the LPA signal transduction pathway responsible for ROS generation and DNA synthesis in RASM cells. At same time, the enzyme could also represent an essential target for the antiproliferative effects of ANP.
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MESH Headings
- Androstadienes/pharmacology
- Animals
- Aorta/cytology
- Atrial Natriuretic Factor/pharmacology
- Atrial Natriuretic Factor/physiology
- Cells, Cultured
- DNA Replication/drug effects
- Enzyme Activation
- Lysophospholipids/antagonists & inhibitors
- Lysophospholipids/pharmacology
- Male
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Phosphoinositide-3 Kinase Inhibitors
- Phosphorylation
- Protein Kinase Inhibitors/pharmacology
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/agonists
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Rats
- Rats, Wistar
- Reactive Oxygen Species/metabolism
- Receptors, Lysophosphatidic Acid/genetics
- Receptors, Lysophosphatidic Acid/metabolism
- Signal Transduction
- Wortmannin
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Affiliation(s)
- P M Baldini
- Department of Biology, University of Rome Tor Vergata, Rome, Italy.
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134
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Shida D, Kitayama J, Yamaguchi H, Yamashita H, Mori K, Watanabe T, Nagawa H. Lysophosphatidic acid transactivates both c-Met and epidermal growth factor receptor, and induces cyclooxygenase-2 expression in human colon cancer LoVo cells. World J Gastroenterol 2005; 11:5638-43. [PMID: 16237757 PMCID: PMC4481480 DOI: 10.3748/wjg.v11.i36.5638] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine whether lysophosphatidic acid (LPA) induces phosphorylation of c-Met and epidermal growth factor receptor (EGFR), both of which have been proposed as prognostic markers of colorectal cancer, and whether LPA induces cyclooxygenase-2 (COX-2) expression in human colon cancer cells.
METHODS: Using a human colon cancer cell line, LoVo cells, we performed immunoprecipitation analysis, followed by Western blot analysis. We also examined whether LPA induced COX-2 expression, by Western blot analysis.
RESULTS: Immunoprecipitation analysis revealed that 10 µmol/L LPA induced tyrosine phosphorylation of c-Met and EGFR in LoVo cells within a few minutes. We found that c-Met tyrosine phosphorylation induced by LPA was not attenuated by pertussis toxin or a matrix metalloproteinase inhibitor, in marked contrast to the results for EGFR. In addition, 0.2-40 µmol/L LPA induced COX-2 expression in a dose-dependent manner.
CONCLUSION: Our results suggest that LPA acts upstream of various receptor tyrosine kinases (RTKs) and COX-2, and thus may act as a potent stimulator of colorectal cancer.
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Affiliation(s)
- Dai Shida
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Japan.
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135
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Nakamoto T, Yasuda K, Yasuhara M, Yoshimura T, Kinoshita T, Nakajima T, Okada H, Ikuta A, Kanzaki H. Expression of the endothelial cell differentiation gene 7 (EDG-7), a lysophosphatidic acid receptor, in ovarian tumor. J Obstet Gynaecol Res 2005; 31:344-51. [PMID: 16018784 DOI: 10.1111/j.1447-0756.2005.00299.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Lysophosphatidic acid (LPA) has received attention as a mitogen because the physiologically active lipid stimulates ovarian cancer cell growth by interacting with specific receptors, the endothelial cell differentiation gene (EDG) family. In the present study, we have investigated the expression of EDG-7 mRNA, part of the EDG family, in both human ovarian cancers and established human ovarian cancer cell lines. METHODS RNA was extracted from six ovarian cancer cell lines and multiple cancerous and normal ovarian tissues. The expression of EDG-7 mRNA was measured using reverse transcription-polymerase chain reaction and northern blotting, using reduced glyceraldehyde-phosphate dehydrogenase and S26 as internal controls. RESULTS Of the cell lines tested, EDG-7 mRNA was expressed most intensely in CRL-11731 and CRL-1572 and at a lesser but still substantial level in CRL-11732. The expression of EDG-7 mRNA was limited in MCAS, CRL-11730 and TYKnu. In the ovarian cancer tissues, EDG-7 mRNA was expressed most highly in endometrioid adenocarcinoma and serous cystadenocarcinoma. The expression of EDG-7 mRNA was limited in clear cell adenocarcinoma and undetectable in mucinous cystadenocarcinoma. CONCLUSIONS The intense EDG-7 expression in ovarian cancers suggests that the relation between LPA and EDG-7 (an LPA receptor) is involved in cancer cell growth and proliferation in some histologic subtypes of ovarian cancer.
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Affiliation(s)
- Tsuyoshi Nakamoto
- Department of Obstetrics and Gynecology, Kansai Medical University, Osaka, Japan
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136
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Zhao Y, Usatyuk P, Cummings R, Saatian B, He D, Watkins T, Morris A, Spannhake E, Brindley D, Natarajan V. Lipid phosphate phosphatase-1 regulates lysophosphatidic acid-induced calcium release, NF-kappaB activation and interleukin-8 secretion in human bronchial epithelial cells. Biochem J 2005; 385:493-502. [PMID: 15461590 PMCID: PMC1134721 DOI: 10.1042/bj20041160] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
LPA (lysophosphatidic acid), a potent bioactive phospholipid, elicits diverse cellular responses through activation of the G-protein-coupled receptors LPA1-LPA4. LPA-mediated signalling is partially regulated by LPPs (lipid phosphate phosphatases; LPP-1, -2 and -3) that belong to the phosphatase superfamily. This study addresses the role of LPPs in regulating LPA-mediated cell signalling and IL-8 (interleukin-8) secretion in HBEpCs (human bronchial epithelial cells). Reverse transcription-PCR and Western blotting revealed the presence and expression of LPP-1-3 in HBEpCs. Exogenous [3H]oleoyl LPA was hydrolysed to [3H]-mono-oleoylglycerol. Infection of HBEpCs with an adenoviral construct of human LPP-1 for 48 h enhanced the dephosphorylation of exogenous LPA by 2-3-fold compared with vector controls. Furthermore, overexpression of LPP-1 partially attenuated LPA-induced increases in the intracellular Ca2+ concentration, phosphorylation of IkappaB (inhibitory kappaB) and translocation of NF-kappaB (nuclear factor-kappaB) to the nucleus, and almost completely prevented IL-8 secretion. Infection of cells with an adenoviral construct of the mouse LPP-1 (R217K) mutant partially attenuated LPA-induced IL-8 secretion without altering LPA-induced changes in intracellular Ca2+ concentration, phosphorylation of IkappaB, NF-kappaB activation or IL-8 gene expression. Our results identify LPP-1 as a key regulator of LPA signalling and IL-8 secretion in HBEpCs. Thus LPPs could represent potential targets in regulating leucocyte infiltration and airway inflammation.
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Affiliation(s)
- Yutong Zhao
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Peter V. Usatyuk
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Rhett Cummings
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Bahman Saatian
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Donghong He
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Tonya Watkins
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
| | - Andrew Morris
- †Department of Cell Biology, University of North Carolina, Chapel Hill, NC, U.S.A
| | - Ernst Wm. Spannhake
- ‡Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, U.S.A
| | - David N. Brindley
- §Department of Biochemistry and Signal Transduction Research Group, University of Alberta, Edmonton, Canada
| | - Viswanathan Natarajan
- *Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21222, U.S.A
- To whom correspondence should be addressed: Division of Pulmonary and Critical Care, Johns Hopkins University Medical School, Mason F. Lord Building, Center Tower, 675, 5200 Eastern Avenue, Baltimore, MD, U.S.A. (email )
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137
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Engstler M, Weise F, Bopp K, Grünfelder CG, Günzel M, Heddergott N, Overath P. The membrane-bound histidine acid phosphatase TbMBAP1 is essential for endocytosis and membrane recycling in Trypanosoma brucei. J Cell Sci 2005; 118:2105-18. [PMID: 15855239 DOI: 10.1242/jcs.02327] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the parasitic protozoan Trypanosoma brucei, endocytosis and exocytosis occur exclusively at an invagination of the plasma membrane around the base of the flagellum, called the flagellar pocket, which actively communicates by vesicular membrane flow with cisternal/tubulovesicular endosomes. The division of the cell surface into three morphologically distinct sub-domains and the rapid plasma membrane turnover establishes T. brucei as an interesting model for investigations on the sorting and recycling of membrane proteins. In this study we show that the type I membrane protein TbMBAP1, an L-(+)-tartrate-sensitive acid phosphatase, is present in all endosomal membranes but is virtually absent from the lysosome membrane (where this type of protein is mainly found in other organisms) and is not detectable at the cell surface. The endosomal localization of TbMBAP1 is a function of protein abundance. Moderate overexpression (three- to fourfold) leads to an increased appearance within the flagellar pocket membrane. At higher levels the protein is found in the flagellum, and routing to the pellicular plasma membrane is observed at levels 10- to 25-fold above that of wild type. In other organisms L-(+)-tartrate-sensitive acid phosphatases appear to be dispensable but TbMBAP1 is essential, as shown by RNA interference, which causes growth arrest followed by cell death. Comparison of the phenotype of TbMBAP1-depleted cells with that of cells in which endocytosis or exocytosis has been specifically inhibited by RNAi against clathrin of RAB11, reveals that TbMBAP1 is essential for both incoming and recycling membrane traffic. During differentiation of the organism from bloodstream to insect stage, TbMBAP1 is down-regulated and differentially modified in parallel with a 10-fold decrease in the rate of endocytosis.
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Affiliation(s)
- Markus Engstler
- Ludwig-Maximilians-Universität, Department Biologie I, Genetik, Maria-Ward-Strasse 1a, München, 80638, Germany.
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138
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Shida D, Kitayama J, Yamaguchi H, Yamashita H, Mori K, Watanabe T, Nagawa H. Lysophospholipids transactivate HER2/neu (erbB-2) in human gastric cancer cells. Biochem Biophys Res Commun 2005; 327:907-14. [PMID: 15649431 DOI: 10.1016/j.bbrc.2004.12.088] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2004] [Indexed: 12/31/2022]
Abstract
The ligand-less receptor HER2/neu (erbB-2) has been proposed as a prognostic marker of gastric cancer that correlates with poor clinical outcome, indicating that HER2 signals play an important role in gastric cancer progression. This study demonstrated that two major natural lysophospholipids, lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), induce rapid and transient phosphorylation of HER2 in two human gastric cancer cell lines, MKN28 and MKN74 cells. We also revealed that tyrosine phosphorylation of HER2 induced by both lysophospholipids was significantly attenuated by two inhibitors, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, AG1478, and a broad-spectrum matrix metalloproteinase inhibitor, GM6001. This suggests that the pathway of HER2 transactivation induced by these lysophospholipids is dependent on the proteolytically released EGFR ligands. Our results indicate that LPA and S1P act upstream of HER2 in gastric cancer cells, and thus may act as potent stimulators of gastric cancer.
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Affiliation(s)
- Dai Shida
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, Tokyo 113-8655, Japan.
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139
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Haque W, Garg A, Agarwal AK. Enzymatic activity of naturally occurring 1-acylglycerol-3-phosphate-O-acyltransferase 2 mutants associated with congenital generalized lipodystrophy. Biochem Biophys Res Commun 2005; 327:446-53. [PMID: 15629135 DOI: 10.1016/j.bbrc.2004.12.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Indexed: 10/26/2022]
Abstract
Mutations in the gene encoding 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2) have been reported in patients with congenital generalized lipodystrophy (CGL). AGPAT2, a 278 amino acid protein, belongs to the acyltransferase enzyme family, and has two conserved motifs, NHX(4)D and EGTR, involved in the enzymatic activity. The AGPATs catalyze acylation of lysophosphatidic acid (LPA) to phosphatidic acid (PA) during the biosynthesis of glycerophospholipids and triglycerides from glycerol-3-phosphate. The present studies were designed to determine the enzymatic activity of AGPAT2 mutants found in CGL patients to provide a molecular explanation for the phenotype and to obtain additional information about the structure-function relationship of AGPAT2 protein. The enzymatic activities of the wild type AGPAT2 and mutants were determined in cell lysates of overexpressing Chinese hamster ovary cells by measuring the conversion of [(3)H]LPA to [(3)H]PA in the presence of oleoyl-coenzyme A. Whereas, the R68X, 221delGT, 252delMRT, D180fsX251, and V167fsX183 mutants had markedly reduced enzymatic activity (median <15% of the wild type), the mutants, 140delF, G136R, and L228P, retained median activity ranging from 15% to 40% of the wild type enzyme. However, the missense mutant, A239V, had 90% of the wild type activity. We suggest that reduction in AGPAT2 enzymatic activity underlies the loss of adipose tissue in CGL. Our observations reveal an important role of various carboxy-terminal residues in determining the enzymatic activity of AGPAT2.
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Affiliation(s)
- Wasim Haque
- Division of Nutrition and Metabolic Diseases, Department of Internal Medicine, Center for Human Nutrition, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
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140
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Nogaroli L, Silva OF, Bonilha TA, Moreno PAM, Bernardo RR, Vieyra A, Einicker-Lamas M. Diacylglycerol kinase activity in purified basolateral membranes of kidney tubules. I. Evidence for coupling with phospholipase C. Int J Biochem Cell Biol 2005; 37:79-90. [PMID: 15381152 DOI: 10.1016/j.biocel.2004.05.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Revised: 05/14/2004] [Accepted: 05/17/2004] [Indexed: 10/26/2022]
Abstract
The diacylglycerol kinase (DGK) catalyzes the phosphorylation of diacylglycerol (DAG) yielding phosphatidic acid (PA) signaling molecules which are involved in the modulation of different cell responses. The aim of this work was to characterize the DGK activity associated to the basolateral membranes (BLM) of kidney proximal tubules, in a native preparation that preserves the membrane microenvironment. The Arrhenius plot of DGK activity was non-linear, indicating a complex influence of the lipid environment of the native membrane. The formation of PA was strongly impaired by U73122, an inhibitor of PLC, whereas remained unmodified when exogenous DAG or PLC were added. The Mg.ATP2- complex is the true phosphoryl-donor substrate, and the very narrow peak of activation at pH 7.0 suggests that amino acids that dissociate at this pH, i.e. hystidine residues, play a role by acting in the coordination of the Mg2+ atoms. The renal DGK is almost completely blocked by 0.1 mM sphingosine, but it is insensitive to micromolar free Ca2+ concentrations and to R59499, the most potent inhibitor of the classical DGKs. Taken as a whole, these data suggest that the DGK isoform present in BLM of proximal tubules is different from those included in the type I family, and that membranous PLC could be the main source of DAG for DGK catalysis.
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Affiliation(s)
- Luciana Nogaroli
- Laboratório de Fisico-Química Biológica Aída Hassón-Voloch, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21949-900, Rio de Janerio, Brazil
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141
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Shida D, Kitayama J, Yamaguchi H, Yamashita H, Mori K, Watanabe T, Yatomi Y, Nagawa H. Sphingosine 1-phosphate transactivates c-Met as well as epidermal growth factor receptor (EGFR) in human gastric cancer cells. FEBS Lett 2005; 577:333-8. [PMID: 15556605 DOI: 10.1016/j.febslet.2004.10.024] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2004] [Revised: 09/30/2004] [Accepted: 10/01/2004] [Indexed: 01/12/2023]
Abstract
Receptor tyrosine kinases (RTKs) are transactivated by the stimulation of G protein-coupled receptors (GPCRs). Sphingosine 1-phosphate (S1P), a ligand of GPCR, is known as a tumor-promoting lipid, but its signaling pathways are not fully understood. We here demonstrated that S1P induces rapid and transient tyrosine phosphorylation of epidermal growth factor receptor (EGFR) and c-Met in gastric cancer cells, both of which have been proposed as prognostic markers of gastric cancers. The pathway of S1P-induced c-Met transactivation is Gi-independent and matrix metalloproteinase-independent, which differs from that of EGFR transactivation. Our results indicate that S1P acts upstream of various RTKs and thus may act as a potent stimulator of gastric cancer.
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Affiliation(s)
- Dai Shida
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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142
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Tou JS, Gill JS. Lysophosphatidic acid increases phosphatidic acid formation, phospholipase D activity and degranulation by human neutrophils. Cell Signal 2005; 17:77-82. [PMID: 15451027 DOI: 10.1016/j.cellsig.2004.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Accepted: 06/08/2004] [Indexed: 02/07/2023]
Abstract
I-oleoyl-sn-glycero-3-phosphate, a lysophosphatidic acid (LPA), in serum is a biologically active lipid and has multiple functions depending on the cell types. Several studies have shown that LPA stimulates phospholipase D (PLD) activity in fibroblasts and prostate cancer cells in culture. PLD plays a central role in regulating neutrophil functions. One of the functions of the lipid product, phosphatidic acid (PA), of PLD action in neutrophils is to promote degranulation. In the present study, we examined the effect of LPA on PLD activity and degranulation by human neutrophils. The results show that exogenous LPA increased PA formation, PLD activity and degranulation by human neutrophils in a time and concentration dependent manner. These findings suggest that LPA released from activated platelets during blood clotting may participate in bacterial killing and wound healing process. On the other hand, augmented LPA production might be involved in inflammation, causing damage of the host tissues.
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Affiliation(s)
- Jen-Sie Tou
- Department of Biochemistry, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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143
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Aradóttir S, Seidl S, Wurst FM, Jönsson BAG, Alling C. Phosphatidylethanol in Human Organs and Blood: A Study on Autopsy Material and Influences by Storage Conditions. Alcohol Clin Exp Res 2004; 28:1718-23. [PMID: 15547459 DOI: 10.1097/01.alc.0000145687.41646.e5] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Phosphatidylethanol (PEth) is an abnormal phospholipid that is formed and accumulated in mammalian cells that have been exposed to ethanol. PEth has been proposed as a marker of ethanol abuse. This study was conducted to investigate the concentration of PEth in blood and organs obtained during the autopsy of alcoholics. In addition, we performed experiments on rat tissues and human blood to evaluate the effect of various storage conditions on PEth concentrations. METHODS Human tissues and blood from alcoholics and controls were obtained at autopsy and frozen at -20 degrees C until extraction. Blood from healthy donors was incubated with ethanol for 24 hr and thereafter either extracted directly or stored at room temperature, stored at 4 degrees C, frozen at -20 degrees C, or frozen in liquid nitrogen and stored at -80 degrees C before extraction. Rats were given intraperitoneal injections of ethanol and then killed, either while still intoxicated or when sober. Rat organs were homogenized and extracted directly, after a period of storage, and/or after freezing at -20 degrees C. PEth concentration was analyzed using HPLC and verified by mass spectrometry. RESULTS In all rat organs studied, PEth was formed during freezing at -20 degrees C with ethanol present. PEth concentrations of 9 to 205 mumol/liter were observed in the blood obtained at autopsy. The highest value was found in the case with the highest blood alcohol concentration (114 mmol/liter) at the time of death. In the experiments on human blood stored with ethanol present, PEth concentrations were not affected after 72 hr at 4 degrees C or after freezing in liquid nitrogen and storage at -80 degrees C for up to 144 hr but were slightly elevated after 24 hr at room temperature and at -20 degrees C. PEth was found in all organs obtained from the cadavers of alcoholics. Storage of organs at 4 degrees C for 24 hr with ethanol present had no effect on the PEth concentration. The PEth concentration was unaffected when no ethanol was present at the time of freezing. CONCLUSIONS The rat experiments indicated that the very high PEth concentrations found in the organs of the alcoholics were probably largely formed while the organs were frozen at -20 degrees C. Our data suggest that tissue material from bodies that were exposed to ethanol must be stored properly to obtain reliable results from subsequent analysis for PEth. Tissue should not be frozen at -20 degrees C but instead stored refrigerated until extraction, preferably within hours of autopsy, or frozen in liquid nitrogen and stored at -80 degrees C. Blood samples that contain ethanol can be stored refrigerated for up to 72 hr or frozen in liquid nitrogen and stored at -80 degrees C without affecting PEth levels.
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Affiliation(s)
- Steina Aradóttir
- Department of Medical Neurochemistry, Institute of Laboratory Medicine, Lund University, S-221 85 Lund, Sweden.
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144
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Xu Y, Tanaka M, Arai H, Aoki J, Prestwich GD. Alkyl lysophosphatidic acid and fluoromethylene phosphonate analogs as metabolically-stabilized agonists for LPA receptors. Bioorg Med Chem Lett 2004; 14:5323-8. [PMID: 15454220 DOI: 10.1016/j.bmcl.2004.08.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Revised: 08/07/2004] [Accepted: 08/09/2004] [Indexed: 11/28/2022]
Abstract
We describe an efficient method for the synthesis of alkyl lysophosphatidic acid (LPA) analogs as well as alkyl LPA mono- and difluoromethylene phosphonate analogs. Each alkyl LPA analog was evaluated for subtype-specific LPA receptor agonist activity using a cell migration assay for LPA(1) activation in cancer cells and an intracellular calcium mobilization assay for LPA(2) and LPA(3) activation. Alkyl LPAs induced pronounced cell migration activity with equivalent or higher potency than sn-1-oleoyl LPA, while the alkyl LPA fluoromethylene phosphonates proved to be less potent agonists in this assay. However, each alkyl LPA analog activated Ca(2+) release by activation of LPA(2) and LPA(3) receptors. Interestingly, the absolute configuration of the sn-2 hydroxyl group of the alkyl LPA analogs was not recognized by any of the three LPA receptors. The use of alkyl LPA analogs further expands the scope of structure-activity studies, which will better define LPA-LPA receptor interactions.
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Affiliation(s)
- Yong Xu
- Department of Medicinal Chemistry, University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, UT 84108-1257, USA
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145
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Shida D, Watanabe T, Aoki J, Hama K, Kitayama J, Sonoda H, Kishi Y, Yamaguchi H, Sasaki S, Sako A, Konishi T, Arai H, Nagawa H. Aberrant expression of lysophosphatidic acid (LPA) receptors in human colorectal cancer. J Transl Med 2004; 84:1352-62. [PMID: 15220934 DOI: 10.1038/labinvest.3700146] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a simple bioactive phospholipid with diverse effects on various cells, that interacts with three G protein-coupled transmembrane receptors, LPA1, LPA2, and LPA3. The expression pattern and functions of these LPA receptors in various tumors have not been fully examined, except in ovarian cancer. To evaluate the LPA receptor expression profile in human colorectal cancer and in normal mucosa, we used real-time reverse transcription-polymerase chain reaction (RT-PCR) and measured the expression levels of LPA1, LPA2, and LPA3 messenger RNA (mRNA) in 26 colorectal cancers and 16 corresponding normal tissue samples. Normal epithelium expressed both LPA1 and LPA2 mRNA at similar levels. In comparison, colorectal cancers expressed LPA1 mRNA at a significantly lower level (0.3-fold; P<0.05), and LPA2 mRNA at a significantly higher level (three-fold; P<0.05), as compared with normal tissues. Thus, the ratio of LPA2/LPA1 increased markedly during malignant transformation (18-fold increase). LPA3 mRNA was expressed at only a low level in both normal and cancer tissues. We also assessed LPA2 expression immunohistochemically using a rat anti-LPA2 monoclonal antibody, and confirmed high expression of LPA2 in colorectal cancer at the protein level. As for LPA1, we examined Western blot analysis for 16 matched normal and cancer tissues. It revealed a significant decrease in the expression of LPA1 protein in cancer tissues compared to normal mucosa in nine of 16 cases, and in the remaining seven cases the expression levels was much the same. These results suggested that alteration of LPA receptor expression might be an important event in the development of colorectal cancer, and therefore, LPA and its receptors could be a chemopreventive target against colorectal cancer.
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Affiliation(s)
- Dai Shida
- Department of Surgical Oncology, University of Tokyo Graduate School of Medicine, Tokyo, Japan.
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146
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Kitayama J, Shida D, Sako A, Ishikawa M, Hama K, Aoki J, Arai H, Nagawa H. Over-expression of lysophosphatidic acid receptor-2 in human invasive ductal carcinoma. Breast Cancer Res 2004; 6:R640-6. [PMID: 15535846 PMCID: PMC1064082 DOI: 10.1186/bcr935] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2004] [Revised: 08/10/2004] [Accepted: 08/26/2004] [Indexed: 02/06/2023] Open
Abstract
Introduction Lysophosphatidic acid (LPA) is a bioactive phospholipid with diverse effects on various cells. It interacts with at least three G-protein-coupled transmembrane receptors, namely LPA1, LPA2 and LPA3, whose expression in various tumours has not been fully characterized. In the present study we characterized the expression profile of LPA receptors in human breast cancer tissue and assessed the possible roles of each receptor. Methods The relative expression levels of each receptor's mRNA against β-actin mRNA was examined in surgically resected invasive ductal carcinomas and normal gland tissue using real-time RT-PCR. LPA2 expression was also examined immunohistochemically using a rat anti-LPA2 monoclonal antibody. Results In 25 cases normal and cancer tissue contained LPA1 mRNA at similar levels, whereas the expression level of LPA2 mRNA was significantly increased in cancer tissue as compared with its normal counterpart (3479.0 ± 426.6 versus 1287.3 ± 466.8; P < 0.05). LPA3 was weakly expressed in both cancer and normal gland tissue. In 48 (57%) out of 84 cases, enhanced expression of LPA2 protein was confirmed in carcinoma cells as compared with normal mammary epithelium by immunohistochemistry. Over-expression of LPA2 was detected in 17 (45%) out of 38 premenopausal women, as compared with 31 (67%) out of 46 postmenopausal women, and the difference was statistically significant (P < 0.05). Conclusion These findings suggest that upregulation of LPA2 may play a role in carcinogenesis, particularly in postmenopausal breast cancer.
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MESH Headings
- Antibodies, Monoclonal/chemistry
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/genetics
- Carcinoma, Ductal, Breast/metabolism
- Carcinoma, Ductal, Breast/pathology
- Female
- Humans
- Immunohistochemistry
- Middle Aged
- Neoplasm Staging
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Lysophosphatidic Acid/biosynthesis
- Receptors, Lysophosphatidic Acid/genetics
- Receptors, Lysophosphatidic Acid/immunology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Joji Kitayama
- Department of Surgical Oncology, The University of Tokyo, Tokyo, Japan.
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147
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Rosseto R, Bibak N, Hajdu J. A new approach to the synthesis of lysophospholipids: preparation of lysophosphatidic acid and lysophosphatidylcholine from p-nitrophenyl glycerate. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.07.161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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148
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Chen X, Yang XY, Wang ND, Ding C, Yang YJ, You ZJ, Su Q, Chen JH. Serum lysophosphatidic acid concentrations measured by dot immunogold filtration assay in patients with acute myocardial infarction. Scandinavian Journal of Clinical and Laboratory Investigation 2004; 63:497-503. [PMID: 14743959 DOI: 10.1080/00365510310003265] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study the relation between lysophosphatidic acid (LPA) and myocardial infarction was investigated, the typical and simplified methods for measuring serum LPA concentration by dot immunogold filtration assay (DIFA) based on a polyclonal antibody to LPA were developed, and serum LPA concentrations were measured in 31 patients with acute myocardial infarction (AMI) and 12 controls (blood donors) by DIFA. Serum LPA levels were raised more than twofold 8 h after the onset of AMI. Maximal elevation (10.43 mg/L) was found at 48-72 h following onset and remained higher than the control concentration (1.66 mg/L) 7 days after AMI. The rise in serum LPA concentration in AMI patients suggests that LPA might be involved in AMI-related pathophysiology in the cardiovascular system. The simplified DIFA developed in the present study for measuring serum LPA concentration is convenient and highly sensitive.
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Affiliation(s)
- X Chen
- Division of Biochemistry, Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China
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149
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Lee H, Lin CI, Liao JJ, Lee YW, Yang HY, Lee CY, Hsu HY, Wu HL. Lysophospholipids increase ICAM-1 expression in HUVEC through a Gi- and NF-kappaB-dependent mechanism. Am J Physiol Cell Physiol 2004; 287:C1657-66. [PMID: 15294853 DOI: 10.1152/ajpcell.00172.2004] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S-1-P) are both low molecular weight lysophospholipid (LPL) ligands that are recognized by the Edg family of G protein-coupled receptors. In endothelial cells, these two ligands activate Edg receptors, resulting in cell proliferation and cell migration. The intercellular adhesion molecule-1 (ICAM-1, CD54) is one of many cell adhesion molecules belonging to the immunoglobulin superfamily. This study showed that LPA and S-1-P enhance ICAM-1 expression at both the mRNA and protein levels in human umbilical cord vein endothelial cells (HUVECs). This enhanced ICAM-1 expression in HUVECs was first observed at 2 h postligand treatment. Maximal expression appeared at 8 h postligand treatment, as detected by flow cytometry and Western blotting. Furthermore, the effects of S-1-P on ICAM-1 expression were shown to be concentration dependent. Prior treatment of HUVECs with pertussis toxin, a specific inhibitor of G(i), ammonium pyrrolidinedithiocarbamate and BAY 11-7082, inhibitors of the nuclear factor (NF)-kappaB pathway, or Clostridium difficile toxin B, an inhibitor of Rac, prevented the enhanced effect of LPL-induced ICAM-1 expression. However, pretreatment of HUVECs with exoC3, an inhibitor of Rho, had no effect on S-1-P-enhanced ICAM-1 expression. In a static cell-cell adhesion assay system, pretreatment of LPL enhanced the adhesion between HUVECs and U-937 cells, a human mononucleated cell line. The enhanced adhesion effect could be prevented by preincubation with a functional blocking antibody against human ICAM-1. These results suggest that LPLs released by activated platelets might enhance interactions of leukocytes with the endothelium through a G(i)-, NF-kappaB-, and possibly Rac-dependent mechanism, thus facilitating wound healing and inflammation processes.
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Affiliation(s)
- Hsinyu Lee
- Department of Life Science and Institute of Zoology, National Taiwan University, Taipei, Taiwan 106, ROC.
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150
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Liu Z, Armant DR. Lysophosphatidic acid regulates murine blastocyst development by transactivation of receptors for heparin-binding EGF-like growth factor. Exp Cell Res 2004; 296:317-26. [PMID: 15149861 DOI: 10.1016/j.yexcr.2004.02.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 02/03/2004] [Indexed: 11/25/2022]
Abstract
Transient elevation of intracellular calcium (Ca2+(i)) by various means accelerates murine preimplantation development and trophoblast differentiation. Several G-protein-coupled receptors (GPCRs), including the lysophosphatidic acid (LPA) receptor (LPAR), induce Ca2+(i) transients and transactivate the EGF receptor (ErbB1) through mobilization of EGF family members, including heparin-binding EGF-like growth factor (HB-EGF). Because HB-EGF accelerates blastocyst differentiation in vitro, we examined whether crosstalk between LPA and HB-EGF regulates peri-implantation development. During mouse blastocyst differentiation, embryos expressed LPAR1 mRNA constitutively, LPAR2 only in late stage blastocysts and no LPAR3. Consistent with a mechanism based on Ca2+(i) signaling, LPA rapidly accelerated the rate of trophoblast outgrowth, an index of blastocyst differentiation, and chelation of Ca2+(i) with BAPTA-AM blocked LPA stimulation. Interfering with HB-EGF signaling through ErbB1 or ErbB4 also attenuated LPA stimulation. We established that mouse blastocysts indeed express HB-EGF and that LPA induces the transient accumulation of HB-EGF on the embryo surface, which was blocked by treatment with either BAPTA-AM or the protein trafficking inhibitor, brefeldin A. We conclude that LPA accelerates blastocyst differentiation through its ability to induce Ca2+(i) transients and HB-EGF autocrine signaling. Transactivation of ErbB1 or ErbB4 by HB-EGF could represent a convergent signaling pathway accessed in the trophoblast by stimuli that mobilize Ca2+(i).
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Affiliation(s)
- Zitao Liu
- C.S. Mott Center for Human Growth and Development, Departments of Obstetrics and Gynecology, and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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