title: p2y5/LPA(6) attenuates LPA(1)-mediated VE-cadherin translocation and cell-cell dissociation through G(12/13) protein-Src-Rap1.
abstract: OBJECTIVE
  We investigated the mechanisms of action of lysophosphatidic acid (LPA) to regulate vascular endothelial (VE)-cadherin dynamics and cell-cell contact.
  
  
  RESULTS
  While a low concentration of LPA stimulated VE-cadherin internalization and subsequent cell-cell dissociation, a high concentration of LPA masked the disruptive actions on VE-cadherin and protected the barrier function in human vascular endothelial cells. Knockdown experiments of major LPA receptor subtypes, i.e. LPA(1) and p2y5 (also termed LPA(6)), with their specific small interfering RNAs, showed that LPA(1) and LPA(6) mediate the LPA-induced disruptive and protective actions on barrier integrity, respectively. LPA(6)-mediated tube formation, reflecting stabilization of barrier integrity, was confirmed by in vitro angiogenesis assay. The LPA(1)-mediated disruptive actions were inhibited by pertussis toxin, dominant-negative Rac1, and inhibitors for c-Jun NH(2)-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK), but not by dominant-negative RhoA. In contrast, the LPA(6)-mediated protective actions were associated with activation of Src and Rap1 and attenuated by abrogation of their activities. Further characterization showed that Rap1 is located downstream of Src and dependent on C3G, a Rap1 guanine nucleotide exchange factor. Finally, an LPA antagonist significantly inhibited lactic acid-induced limb lesions in vivo, which may be attributed to dysfunction of endothelial cells.
  
  
  CONCLUSIONS
  LPA induced disruption and protection of VE-cadherin integrity through LPA(1)-G(i) protein-Rac1-JNK/p38MAPK and LPA(6)-G(12/13) protein-Src-C3G-Rap1 pathways, respectively.
authors.affiliation: Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi 371-8512, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Kimura
authors.forename: Chihiro
authors.initials: C
authors.lastname: Mogi
authors.forename: Koichi
authors.initials: K
authors.lastname: Sato
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tomura
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohta
authors.forename: Doon-Soon
authors.initials: DS
authors.lastname: Im
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kuwabara
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurose
authors.forename: Masami
authors.initials: M
authors.lastname: Murakami
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Okajima
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D002478:Cells, Cultured; D044365:GTP-Binding Protein alpha Subunits, G12-G13 / Q000502:physiology*; D020690:GTPase-Activating Proteins / Q000502:physiology*; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology; D048670:MAP Kinase Kinase 4 / Q000502:physiology; D008297:Male; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D049368:Receptors, Lysophosphatidic Acid / Q000502:physiology*; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology; D019061:src-Family Kinases / Q000502:physiology*; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D044365:GTP-Binding Protein alpha Subunits, G12-G13; D020690:GTPase-Activating Proteins; D008246:Lysophospholipids; D048670:MAP Kinase Kinase 4; D049368:Receptors, Lysophosphatidic Acid; D018048:Receptors, Purinergic P2; D048051:p38 Mitogen-Activated Protein Kinases; D019061:src-Family Kinases; D000099152:Cadherin 5; C082320:LPAR4 protein, human; C500320:RAP1GAP2 protein, human; C032881:lysophosphatidic acid