Fer kinase limits neutrophil chemotaxis toward end target chemoattractants.
Neutrophil recruitment and directional movement toward chemotactic stimuli are important processes in innate immune responses. This study examines the role of Fer kinase in neutrophil recruitment and chemotaxis to various chemoattractants in vitro and in vivo. Mice targeted with a kinase-inactivating mutation (Fer(DR/DR)) or wild type (WT) were studied using time-lapse intravital microscopy to examine leukocyte recruitment and chemotaxis in vivo. In response to keratinocyte-derived cytokine, no difference in leukocyte chemotaxis was observed between WT and Fer(DR/DR) mice. However, in response to the chemotactic peptide WKYMVm, a selective agonist of the formyl peptide receptor, a 2-fold increase in leukocyte emigration was noted in Fer(DR/DR) mice (p < 0.05). To determine whether these defects were due to Fer signaling in the endothelium or other nonhematopoietic cells, bone marrow chimeras were generated. WKYMVm-induced leukocyte recruitment in chimeric mice (WT bone marrow to Fer(DR/DR) recipients or vice versa) was similar to WT mice, suggesting that Fer kinase signaling in both leukocytes and endothelial cells serves to limit chemotaxis. Purified Fer(DR/DR) neutrophils demonstrated enhanced chemotaxis toward end target chemoattractants (WKYMVm and C5a) compared with WT using an under-agarose gel chemotaxis assay. These defects were not observed in response to intermediate chemoattractants (keratinocyte-derived cytokine, MIP-2, or LTB(4)). Increased WKYMVm-induced chemotaxis of Fer(DR/DR) neutrophils correlated with sustained PI3K activity and reduced reliance on the p38 MAPK pathway compared with WT neutrophils. Together, these data identify Fer as a novel inhibitory kinase for neutrophil chemotaxis toward end target chemoattractants through modulation of PI3K activity.
Department of Physiology and Pharmacology, Gastrointestinal Research Group, Institute of Inflammation, Immunity, and Infection, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Maitham
M
Khajah
Graciela
G
Andonegui
Ronald
R
Chan
Andrew W
AW
Craig
Peter A
PA
Greer
Donna-Marie
DM
McCafferty
D000818:Animals; D054426:Chemokine CXCL2 / Q000494:pharmacology; D018925:Chemokines / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D015870:Gene Expression / Q000187:drug effects; D007958:Leukocyte Count; D007975:Leukotriene B4 / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D018715:Microscopy, Video; D020556:Neutrophil Infiltration / Q000187:drug effects*; D009504:Neutrophils / Q000166:cytology* / Q000276:immunology; D010455:Peptides / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000276:immunology; D044042:Receptors, Formyl Peptide / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects; D059008:Time-Lapse Imaging; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000276:immunology
D054426:Chemokine CXCL2; D018925:Chemokines; D002630:Chemotactic Factors; C404915:Cxcl2 protein, mouse; D016207:Cytokines; D010455:Peptides; D044042:Receptors, Formyl Peptide; C052602:proto-oncogene protein c-fes-fps; C074302:keratinocyte-derived chemokines; D007975:Leukotriene B4; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; D048051:p38 Mitogen-Activated Protein Kinases