IL-8 activates endothelial cell CXCR1 and CXCR2 through Rho and Rac signaling pathways.
Stimulation of microvascular endothelial cells with interleukin (IL)-8 leads to cytoskeletal reorganization, which is mediated by combined activation of the CXCR1 and the CXCR2. In the early phase actin stress fibers appear, followed by cortical actin accumulation and cell retraction leading to gap formation between cells. The early response (between 1 and 5 min) is inhibited by an antibody that blocks the CXCR1. The later phase (from about 5 to 60 min), which is associated with cell retraction, is prevented by anti-CXCR2 antibody. Furthermore, anti-CXCR2, but not anti-CXCR1, antibody blocked IL-8-mediated haptotaxis of endothelial cells on collagen. The later phase of the IL-8-mediated actin response is inhibited by pertussis toxin, indicating that the CXCR2 couples to G(i). In contrast, the early phase is blocked by C3 botulinum toxin, which inactivates Rho, and by Y-27632, which inhibits Rho kinase, but not by pertussis toxin. Furthermore, the early CXCR1-mediated formation of stress fibers was prevented by dominant negative Rho. Dominant negative Rac on the other hand initially translocated to actin-rich filopodia after stimulation with IL-8 and later prevented cell retraction by blocking the CXCR2-mediated cytoskeletal response. These results indicate that IL-8 activates both the CXCR1 and the CXCR2 on microvascular endothelial cells, using different signal transduction cascades. The retraction of endothelial cells due to activation of the CXCR2 may contribute to the increased vascular permeability observed in acute inflammation and during the angiogenic response.
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La Jolla Institute for Molecular Medicine, 4570 Executive Drive, San Diego, CA 92121, USA. ingrid@ljimm.org
Chung
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Burger
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D036002:ADP Ribose Transferases; D000199:Actins / Q000378:metabolism; D000906:Antibodies / Q000494:pharmacology; D001905:Botulinum Toxins; D002478:Cells, Cultured; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8 / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins; D008168:Lung / Q000098:blood supply / Q000166:cytology; D008833:Microcirculation / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D037342:Pertussis Toxin; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D023062:Receptors, Interleukin-8A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D023063:Receptors, Interleukin-8B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D022502:Stress Fibers / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D054460:rho-Associated Kinases
D000199:Actins; D000906:Antibodies; C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D004791:Enzyme Inhibitors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D047908:Intracellular Signaling Peptides and Proteins; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B; D010566:Virulence Factors, Bordetella; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D037342:Pertussis Toxin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D001905:Botulinum Toxins; D020559:Monomeric GTP-Binding Proteins; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins