ICAM-1-coupled cytoskeletal rearrangements and transendothelial lymphocyte migration involve intracellular calcium signaling in brain endothelial cell lines.
Endothelium of the cerebral blood vessels, which constitutes the blood-brain barrier, controls adhesion and trafficking of leukocytes into the brain. Investigating signaling pathways triggered by the engagement of adhesion molecules expressed on brain endothelial cells using two rat brain endothelial cell lines (RBE4 and GP8), we report in this paper that ICAM-1 cross-linking induces a sustained tyrosine phosphorylation of the phosphatidylinositol-phospholipase C (PLC)gamma1, with a concomitant increase in both inositol phosphate production and intracellular calcium concentration. Our results suggest that PLC are responsible, via a calcium- and protein kinase C (PKC)-dependent pathway, for p60Src activation and tyrosine phosphorylation of the p60Src substrate, cortactin. PKCs are also required for tyrosine phosphorylation of the cytoskeleton-associated proteins, focal adhesion kinase and paxillin, but not for ICAM-1-coupled p130Cas phosphorylation. PKC's activation is also necessary for stress fiber formation induced by ICAM-1 cross-linking. Finally, cell pretreatment with intracellular calcium chelator or PKC inhibitors significantly diminishes transmonolayer migration of activated T lymphocytes, without affecting their adhesion to brain endothelial cells. In summary, our data demonstrate that ICAM-1 cross-linking induces calcium signaling which, via PKCs, mediates phosphorylation of actin-associated proteins and cytoskeletal rearrangement in brain endothelial cell lines. Our results also indicate that these calcium-mediated intracellular events are essential for lymphocyte migration through the blood-brain barrier.
Etienne-Manneville
S
S
Centre National de la Recherche Scientifique, Unité Propre de Recherche 0415, Cell Biology Department, Institut Cochin de Génétique Moléculaire, Université Paris VII, Paris, France. s.etienne-manneville@ucl.ac.uk
Manneville
J B
JB
Adamson
P
P
Wilbourn
B
B
Greenwood
J
J
Couraud
P O
PO
D000199:Actins / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000502:physiology*; D002118:Calcium / Q000378:metabolism / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology*; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000502:physiology; D051356:Cortactin; D003599:Cytoskeleton / Q000378:metabolism* / Q000502:physiology; D004729:Endothelium, Lymphatic / Q000166:cytology / Q000502:physiology*; D004789:Enzyme Activation; D007295:Inositol Phosphates / Q000096:biosynthesis; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism* / Q000502:physiology; D007424:Intracellular Fluid / Q000502:physiology*; D008214:Lymphocytes / Q000502:physiology*; D008840:Microfilament Proteins / Q000378:metabolism; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D010738:Type C Phospholipases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D000199:Actins; D051356:Cortactin; C495870:Cttn protein, rat; D007295:Inositol Phosphates; D008840:Microfilament Proteins; D018799:Intercellular Adhesion Molecule-1; D014443:Tyrosine; D015688:Oncogene Protein pp60(v-src); D011493:Protein Kinase C; D010738:Type C Phospholipases; D002118:Calcium