Reference - Detail
|Author||Sashio T, Kume H, Takeda N, Asano T, Tsuji S, Kondo M, Hasegawa Y, Shimokata K.|
|Title||Possible Involvement of Sphingosine-1-Phosphate/G(i)/RhoA pathways in adherence of eosinophils to pulmonary endothelium.|
BACKGROUND:Sphingosine-1-phosphate (S1P), a lysophospholipid released from inflammatory cells, causes cell migration by increasing cytokines and chemokines. This study was designed to determine whether S1P causes adherence of eosinophils to pulmonary endothelial cells via enhancement of adhesion molecule expression.
METHODS:Expression of VCAM-1 and ICAM-1 was assessed by RT-PCR and Western blot analysis in human pulmonary microvasucular endothelial cells (HPMVECs). The number of adherent eosinophils to HPMVECs was calculated according to adhesion assay.
RESULTS:Pre-treatment of HPMVECs with S1P increased mRNA and protein expression of VCAM-1, in contrast, did not dramatically increase those expression of ICAM-1. The maximal expression of these adhesion molecules in mRNA and protein was observed 4 and 8h after exposure to S1P, respectively. Pre-treatment with S1P also activated RhoA, a monomeric G protein; the ability of S1P to enhance the expression of VCAM-1 was attenuated by RhoA related inhibitors such as Y-27632, C3 exoenzyme, and GGTI-286. The effects of S1P on VCAM-1 were attenuated by pre-incubation with pertussis toxin, which catalyzes the ADP-ribosylation of G(i), a heterotrimeric G protein. After HPMVECs were treated with S1P, adhesion of human eosinophilic leukemic cell line (EoL-1) cells to HPMVECs was enhanced in a concentration-dependent manner. Augmented adherence of EoL-1 cells by S1P was also attenuated by Y-27632 and pertussis toxin. S1P causes adherence of eosinophils to pulmonary endothelium via RhoA activation.
CONCLUSIONS:S1P may act as a lipid mediator in asthma. The RhoA/Rho-kinase pathway may be a therapeutic target for preventing eosinophil infiltration to the airway.
|MeSH||ADP Ribose Transferases / pharmacology Amides / pharmacology Botulinum Toxins / pharmacology Cell Adhesion / drug effects Cell Adhesion / immunology Cell Line Endothelium, Vascular / drug effects Eosinophils / drug effects Eosinophils / immunology* Gene Expression Regulation / drug effects Gene Expression Regulation / immunology Humans Intercellular Adhesion Molecule-1 / genetics Intercellular Adhesion Molecule-1 / immunology Intercellular Adhesion Molecule-1 / metabolism* Leucine / analogs & derivatives Leucine / pharmacology Lung / pathology Lysophospholipids / pharmacology* Pyridines / pharmacology Signal Transduction / drug effects Signal Transduction / immunology Sphingosine / analogs & derivatives* Sphingosine / pharmacology Vascular Cell Adhesion Molecule-1 / genetics Vascular Cell Adhesion Molecule-1 / immunology Vascular Cell Adhesion Molecule-1 / metabolism* rhoA GTP-Binding Protein / immunology rhoA GTP-Binding Protein / metabolism*|
|WOS Category||ALLERGY IMMUNOLOGY|
|Human and Animal Cells|