CCL11 and GM-CSF differentially use the Rho GTPase pathway to regulate motility of human eosinophils in a three-dimensional microenvironment.
Asthma is a common disease that causes considerable morbidity. Increased numbers of airway eosinophils are a hallmark of asthma. Mechanisms controlling the entry of eosinophils into asthmatic lung have been intensively investigated, but factors regulating migration within the tissue microenvironment are less well understood. We modeled this by studying chemoattractant and growth factor-mediated human eosinophil migration within a three-dimensional collagen matrix. Stimulation with GM-CSF induced dose-dependent, random migration with a maximum of 77 +/- 4.7% of cells migrating. In contrast, CCL11 and C5a caused a more modest although significant degree of migration (19 +/- 1.8% and 20 +/- 2.6%, respectively). Migration to GM-CSF was partially dependent on Ca(2+) and alpha(M)beta(2) integrins. The Rho family of small GTPases regulates intracellular signaling of cell migration. GM-CSF-induced migration was only partially dependent on Rho kinase/Rho-associated kinase (ROCK) and was independent of RhoA activation. In contrast, CCL11-induced migration was fully dependent on both RhoA and ROCK. Activation of RhoA was therefore neither necessary nor sufficient to cause eosinophil migration in a three-dimensional collagen environment. This study suggests that eosinophil growth factors are likely to be required for eosinophil migration within the bronchial mucosa, and this involves signal transduction pathways distinct from those used by G protein-associated chemoattractants.
Institute for Lung Health, Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK.
Michelle J
MJ
Muessel
Karen S
KS
Scott
Peter
P
Friedl
Peter
P
Bradding
Andrew J
AJ
Wardlaw
D019138:Antibodies, Blocking / Q000494:pharmacology; D039481:CD11b Antigen / Q000276:immunology / Q000378:metabolism; D002118:Calcium / Q000037:antagonists & inhibitors / Q000502:physiology; D002464:Cell Migration Inhibition / Q000276:immunology; D002614:Chelating Agents / Q000494:pharmacology; D054413:Chemokine CCL11 / Q000502:physiology*; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D024042:Collagen Type I / Q000502:physiology; D015936:Complement C5a / Q000502:physiology; D004492:Edetic Acid / Q000494:pharmacology; D004804:Eosinophils / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D005782:Gels; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000502:physiology*; D006801:Humans; D015398:Signal Transduction / Q000276:immunology*; D020741:rho GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D054460:rho-Associated Kinases / Q000378:metabolism / Q000502:physiology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism / Q000502:physiology
D019138:Antibodies, Blocking; C515456:CCL11 protein, human; D039481:CD11b Antigen; D002614:Chelating Agents; D054413:Chemokine CCL11; D024042:Collagen Type I; D005782:Gels; C509295:ITGAM protein, human; C066737:RHOA protein, human; D015936:Complement C5a; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004492:Edetic Acid; D054460:rho-Associated Kinases; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D002118:Calcium