Chemotactic factor-induced recruitment and activation of Tec family kinases in human neutrophils. II. Effects of LFM-A13, a specific Btk inhibitor.
Tyrosine phosphorylation events play major roles in the initiation and regulation of several functional responses of human neutrophils stimulated by chemotactic factors such as the bacterially derived tripeptide formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). However, the links between the G protein-coupled receptors, the activation of the tyrosine kinases, and the initiation of neutrophil functional responses remain unclear. In the present study we assessed the effects of a Btk inhibitor, leflunomide metabolite analog (LFM-A13), on neutrophils. LFM-A13 decreased the tyrosine phosphorylation induced by fMet-Leu-Phe and inhibited the production of superoxide anions and the stimulation of adhesion, chemotaxis, and phospholipase D activity. We observed a decreased accumulation of phosphatidylinositol-3,4,5-trisphosphate in response to fMet-Leu-Phe in LFM-A13-pretreated cells even though the inhibitor had no direct effect on the lipid kinase activity of the p110 gamma or p85/p110 phosphatidylinositol 3-kinases or on the activation of p110 gamma by fMet-Leu-Phe. The phosphorylation of Akt and of extracellular signal-regulated kinases 1/2 and p38 were similarly inhibited by LFM-A13. LFM-A13 also negatively affected the translocation of Rac-2, RhoA, ADP ribosylation factor-1, Tec, Bmx, and Btk induced by fMet-Leu-Phe. The results of this study provide evidence for an involvement of Btk and possibly other Tec kinase family members in the regulation of the functional responsiveness of human neutrophils and link these events, in part at least, to the modulation of levels of phosphatidylinositol-3,4,5-trisphosphate.
Canadian Institutes of Health Research Group on the Molecular Mechanisms of Inflammation, Centre de Recherche en Rhumatologie et Immunologie, Centre Hospitalier de l'Universite Laval, Department of Medicine, Laval University, Québec, Canada.
Caroline
C
Gilbert
Sylvain
S
Levasseur
Philippe
P
Desaulniers
Andrée-Anne
AA
Dusseault
Nathalie
N
Thibault
Sylvain G
SG
Bourgoin
Paul H
PH
Naccache
D000328:Adult; D000077329:Agammaglobulinaemia Tyrosine Kinase; D000577:Amides / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology*; D009570:Nitriles / Q000494:pharmacology*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013379:Substrate Specificity / Q000187:drug effects / Q000276:immunology
D000577:Amides; C118451:LFM A13; D009570:Nitriles; D018129:Phosphatidylinositol Phosphates; C060974:phosphatidylinositol 3,4,5-triphosphate; D009240:N-Formylmethionine Leucyl-Phenylalanine; C089848:Tec protein-tyrosine kinase; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human; D010739:Phospholipase D