title: Cross-talk between ICAM-1 and granulocyte-macrophage colony-stimulating factor receptor signaling modulates eosinophil survival and activation.
abstract: Reversal of eosinophilic inflammation has been an elusive therapeutic goal in the management of asthma pathogenesis. In this regard, GM-CSF is a primary candidate cytokine regulating eosinophil activation and survival in the lung; however, its molecular mechanism of propagation and maintenance of stimulated eosinophil activation is not well understood. In this study, we elucidate those late interactions occurring between the GM-CSF receptor and activated eosinophil signaling molecules. Using coimmunoprecipitation with GM-CSF-stimulated eosinophils, we have identified that the GM-CSF receptor beta-chain (GMRbeta) interacted with ICAM-1 and Shp2 phosphatase, as well as Slp76 and ADAP adaptor proteins. Separate experiments using affinity binding with a tyrosine-phosphorylated peptide containing an ITIM (ICAM-1 residues 480-488) showed binding to Shp2 phosphatase and GMRbeta. However, the interaction of GMRbeta with the phosphorylated ICAM-1-derived peptide was observed only with stimulated eosinophil lysates, suggesting that the interaction of GMRbeta with ICAM-1 required phosphorylated Shp2 and/or phosphorylated GMRbeta. Importantly, we found that inhibition of ICAM-1 in activated eosinophils blocked GM-CSF-induced expression of c-fos, c-myc, IL-8, and TNF-alpha. Moreover, inhibition of ICAM-1 expression with either antisense oligonucleotide or an ICAM-1-blocking Ab effectively inhibited ERK activation and eosinophil survival. We concluded that the interaction between ICAM-1 and the GM-CSF receptor was essential for GM-CSF-induced eosinophil activation and survival. Taken together, these results provide novel mechanistic insights defining the interaction between ICAM-1 and the GM-CSF receptor and highlight the importance of targeting ICAM-1 and GM-CSF/IL-5/IL-3 receptor systems as a therapeutic strategy to counter eosinophilia in asthma.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.
authors.forename: Konrad
authors.initials: K
authors.lastname: Pazdrak
authors.forename: Travis W
authors.initials: TW
authors.lastname: Young
authors.forename: Susan
authors.initials: S
authors.lastname: Stafford
authors.forename: Barbara
authors.initials: B
authors.lastname: Olszewska-Pazdrak
authors.forename: Christof
authors.initials: C
authors.lastname: Straub
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Starosta
authors.forename: Allan
authors.initials: A
authors.lastname: Brasier
authors.forename: Alexander
authors.initials: A
authors.lastname: Kurosky
mesh_terms: D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D053648:Cytokine Receptor Common beta Subunit / Q000378:metabolism* / Q000502:physiology; D004804:Eosinophils / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism / Q000502:physiology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism* / Q000502:physiology; D010455:Peptides / Q000378:metabolism / Q000502:physiology; D011485:Protein Binding / Q000276:immunology; D021122:Protein Subunits / Q000378:metabolism / Q000502:physiology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism / Q000502:physiology; D020239:Receptor Cross-Talk / Q000276:immunology; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology
chemical_list: D053648:Cytokine Receptor Common beta Subunit; D010455:Peptides; D021122:Protein Subunits; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D018799:Intercellular Adhesion Molecule-1; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11