Molecular mechanisms involved in interleukin-4-induced human neutrophils: expression and regulation of suppressor of cytokine signaling.
Interleukin-4 (IL-4) is a CD132-dependent cytokine known to activate the Jak-STAT pathway in different cells and cell lines. Although IL-4 has been demonstrated previously to be an agonist in human neutrophils, its capacity to activate different cell signaling pathways in these cells has never been investigated. Two types of IL-4 receptor (IL-4R) exist: the Type I (CD132/IL-4Ralpha heterodimer) and the Type II (IL-4Ralpha/IL-13Ralpha1 heterodimer). In a previous study, we demonstrated that neutrophils express the Type I receptor. Herein, using flow cytometry, we demonstrated that neutrophils, unlike U-937 cells, do not express IL-13Ralpha1 and IL-13Ralpha2 and confirmed the expression of CD132 and IL-4Ralpha on their surface. We also demonstrated that IL-4 induced phosphorylation of Syk, p38, Erk-1/2, JNK, Jak-1, Jak-2, STAT6, and STAT1 and that treatment of cells with the inhibitors piceatannol, SB203580, PD98059, or AG490 reversed the ability of IL-4 to delay neutrophil apoptosis. Using RT-PCR, we demonstrated for the first time that neutrophils express mRNA for all suppressor of cytokine signaling (SOCS) members, namely SOCS1-7 and cytokine-inducible Src homology 2 protein. It is interesting that IL-4 increased expression of SOCS3 at the mRNA and protein levels. The effect of IL-4 on SOCS3 protein expression was increased markedly when the proteasome inhibitor MG132 was added to the cultures, but this was inhibited by cycloheximide, suggesting that SOCS3 is de novo-synthesized in response to IL-4. We conclude that neutrophils express only the Type I IL-4R on their surface and that IL-4 signals via different cell signaling pathways, including the Jak/STAT/SOCS pathway.
Ratthé
Claude
C
INRS-Institut Armand-Frappier, Université du Québec, 245 boul. Hymus, Pointe-Claire (PQ), Canada, H9R 1G6.
Pelletier
Martin
M
Chiasson
Sonia
S
Girard
Denis
D
D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology; D020869:Gene Expression Profiling; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D015847:Interleukin-4 / Q000037:antagonists & inhibitors / Q000502:physiology*; D007976:Leupeptins / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009504:Neutrophils / Q000276:immunology*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D053658:Receptors, Interleukin-4, Type I / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013329:Structure-Activity Relationship; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics* / Q000378:metabolism*; D020032:Tyrphostins / Q000494:pharmacology
D003513:Cycloheximide; D005419:Flavonoids; D016179:Granulocyte Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D007093:Imidazoles; D015847:Interleukin-4; D007976:Leupeptins; D011725:Pyridines; D012333:RNA, Messenger; D053658:Receptors, Interleukin-4, Type I; D050826:Suppressor of Cytokine Signaling Proteins; D020032:Tyrphostins; C095512:alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide; C093642:SB 203580; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one