Lysophosphatidylserine stimulates L2071 mouse fibroblast chemotactic migration via a process involving pertussis toxin-sensitive trimeric G-proteins.
Lysophosphatidylserine (LPS) may be generated after phosphatidylserine-specific phospholipase A2 activation. However, the effects of LPS on cellular activities and the identities of its target molecules have not been fully elucidated. In this study, we observed that LPS stimulates an intracellular calcium increase in L2071 mouse fibroblast cells, and that this increase was inhibited by 1-[6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione (U-73122) but not by pertussis toxin, suggesting that LPS stimulates calcium signaling via G-protein coupled receptor-mediated phospholipase C activation. Moreover, LPS-induced calcium mobilization was not inhibited by the lysophosphatidic acid receptor antagonist, (S)-phosphoric acid mono-{2-octadec-9-enoylamino-3-[4-(pyridine-2-ylmethoxy)-phenyl]-propyl} ester (VPC 32183), thus indicating that LPS binds to a receptor other than lysophosphatidic acid receptors. It was also found that LPS stimulates two types of mitogen-activated protein kinase [i.e., extracellular signal-regulated protein kinase (ERK) and p38 kinase] in L2071 cells. Furthermore, these LPS-induced ERK and p38 kinase activations were inhibited by pertussis toxin, which suggests the role of pertussis toxin-sensitive G-proteins in the process. In terms of functional issues, LPS stimulated L2071 cell chemotactic migration, which was completely inhibited by pertussis toxin, indicating the involvement of pertussis toxin-sensitive G(i) protein(s). This chemotaxis of L2071 cells induced by LPS was also dramatically inhibited by 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) and by 2'-amino-3'-methoxyflavone (PD98059). This study demonstrates that LPS stimulates at least two different signaling cascades, one of which involves a pertussis toxin-insensitive but phospholipase C-dependent intracellular calcium increase, and the other involves a pertussis toxin-sensitive chemotactic migration mediated by phosphoinositide 3-kinase and ERK.
Park
Kyoung Sun
KS
Medical Research Center for Cancer Molecular Therapy and Department of Biochemistry, College of Medicine, Dong-A University, Busan 602-714, Korea.
Lee
Ha-Young
HY
Kim
Mi-Kyoung
MK
Shin
Eun Ha
EH
Jo
Seong Ho
SH
Kim
Sang Doo
SD
Im
Dong-Soon
DS
Bae
Yoe-Sik
YS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002633:Chemotaxis; D004789:Enzyme Activation; D004963:Estrenes / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D005419:Flavonoids / Q000494:pharmacology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000037:antagonists & inhibitors / Q000502:physiology*; D008246:Lysophospholipids / Q000494:pharmacology*; D051379:Mice; D037342:Pertussis Toxin / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D049368:Receptors, Lysophosphatidic Acid / Q000037:antagonists & inhibitors; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D004963:Estrenes; D005419:Flavonoids; D008246:Lysophospholipids; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D049368:Receptors, Lysophosphatidic Acid; C025059:lysophosphatidylserine; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C060506:sphingosine 1-phosphate; D037342:Pertussis Toxin; D051057:Proto-Oncogene Proteins c-akt; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D013110:Sphingosine; C032881:lysophosphatidic acid; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium