Lymphocyte trafficking through the blood-brain barrier is dependent on endothelial cell heterotrimeric G-protein signaling.
We have previously shown that the engagement of ICAM-1 on brain endothelial cells (EC) results in the propagation of EC signaling pathways that are necessary for efficient lymphocyte migration across the tight vascular barriers of the brain. Signaling via this receptor alone, however, is unlikely to explain the differential recruitment of leukocytes at different vascular beds. In this study, we investigated the role of EC heterotrimeric G-protein-mediated signaling in supporting transendothelial migration of T lymphocytes. Treatment of brain EC monolayers with pertussis toxin (PTX) resulted in ADP-ribosylation of G-protein alpha subunits and inhibition (>80%) of lymphocyte migration without affecting lymphocyte adhesion. Aortic and high endothelial venule EC treated identically resulted in only partial inhibition of lymphocyte migration (<40%). Expression of ribosylation-resistant (PTX-insensitive) G-protein alpha subunits in brain EC restored their ability to support lymphocyte migration after pretreatment with PTX. Treatment of brain EC with PTX did not inhibit ICAM-1-stimulated tyrosine phosphorylation of focal adhesion kinase, suggesting the effects of PTX in inhibiting EC facilitation of lymphocyte migration are distinct from activation of EC through ICAM-1. We conclude that a heterotrimeric G-protein-mediated signaling pathway in brain EC is essential for efficient transendothelial migration of T lymphocytes into the brain.
Adamson
Peter
P
Endothelial and Epithelial Cell Biology Research Unit, Division of Cell Biology, Institute of Ophthalmology, University College London, London EC1V 9EL, UK. J.Greenwood@ucl.ac.uk
Wilbourn
Barry
B
Etienne-Manneville
Sandrine
S
Calder
Virginia
V
Beraud
Evelyne
E
Milligan
Graeme
G
Couraud
Pierre-Olivier
PO
Greenwood
John
J
D020727:ADP-Ribosylation Factors / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology; D001812:Blood-Brain Barrier / Q000276:immunology*; D001921:Brain / Q000098:blood supply; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D051356:Cortactin; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology; D008840:Microfilament Proteins / Q000378:metabolism; D009154:Mutation; D037342:Pertussis Toxin; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D051356:Cortactin; C495870:Cttn protein, rat; D008840:Microfilament Proteins; D010566:Virulence Factors, Bordetella; D018799:Intercellular Adhesion Molecule-1; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; C496052:Ptk2 protein, rat; D020962:Heterotrimeric GTP-Binding Proteins; D020727:ADP-Ribosylation Factors