title: Inhibition of CCL11, CCL24, and CCL26-induced degranulation in HL-60 eosinophilic cells by specific inhibitors of MEK1/MEK2, p38 MAP kinase, and PI 3-kinase.
abstract: Eosinophilic leukocytes are the cellular hallmark of allergic inflammation. Apart from being potent eosinophils chemoattractants, the eotaxins CCL11, CCL24 and CCL26 are capable of activating eosinophils to generate reactive oxygen species, lipid mediators of inflammation and degranulation of toxic granule proteins. Due to their central role in eosinophil trafficking and activation, understanding the signal transduction mechanism of the eotaxin-induced eosinophil effector functions may provide an innovative therapeutic strategy for eosinophil-associated diseases. Thus, these investigations were conducted to delineate signal transduction mechanisms of CCL11, CCL24 and CCL26-induced eosinophil peroxidase (EPO) degranulation following pretreatment of cells with or without a specific inhibitor of MEK1/MEK2 (U0126), inhibitor of p38 MAP kinase (SB203580) or a specific inhibitor of PI 3-kinase (LY294002). Results have shown that CCR3-mediated eotaxin-induced eosinophilic degranulation was concentration-dependently reduced by specific inhibitors of ERK1/ERK2, p38 MAP kinase and PI 3-kinase. However, the rank order of U0126 with respect to inhibition of chemokine-induced degranulation was CCL11 = CCL24 > CCL26. Potentiation of eotaxin-induced EPO degranulation by IL-5 was also seen. These investigations have not only confirmed the reported co-operativity between IL-5 and the eotaxins but also showed that the eosinophil-degranulating capabilities of the eotaxin CCL11, CCL24 and CCL26 is a consequence of activation of ERK1/ERK2, p38 MAP kinase and PI 3-kinase. Thus, these signaling molecules may provide the biochemical basis for mechanism-based therapy of allergic inflammatory diseases.
authors.affiliation: College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, Florida 32307, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Badewa
authors.forename: A S
authors.initials: AS
authors.lastname: Heiman
mesh_terms: D002070:Butadienes / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects*; D054413:Chemokine CCL11; D054423:Chemokine CCL24; D000075906:Chemokine CCL26; D019742:Chemokines, CC / Q000494:pharmacology; D002631:Chemotactic Factors, Eosinophil / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D047209:Eosinophil Peroxidase; D004804:Eosinophils / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D018922:HL-60 Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D009570:Nitriles / Q000494:pharmacology; D010544:Peroxidases / Q000037:antagonists & inhibitors; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002070:Butadienes; C515456:CCL11 protein, human; C515484:CCL24 protein, human; C120429:CCL26 protein, human; D054413:Chemokine CCL11; D054423:Chemokine CCL24; D000075906:Chemokine CCL26; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil; D004791:Enzyme Inhibitors; D007093:Imidazoles; D009570:Nitriles; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011725:Pyridines; C113580:U 0126; D047209:Eosinophil Peroxidase; D010544:Peroxidases; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; C093642:SB 203580