The chemoattractants, IL-8 and formyl-methionyl-leucyl-phenylalanine, regulate granulocyte colony-stimulating factor signaling by inducing suppressor of cytokine signaling-1 expression.
Carrier Proteins/genetics/metabolism; Chemotaxis/physiology; Gene Expression Regulation/physiology; Granulocyte Colony-Stimulating Factor/metabolism; Humans; Interleukin-8/metabolism; Intracellular Signaling Peptides and Proteins; Monocytes/metabolism; N-Formylmethionine Leucyl-Phenylalanine/metabolism; Neutrophils/metabolism; Repressor Proteins/genetics/metabolism; Signal Transduction/physiology; Suppressor of Cytokine Signaling Proteins
Abstract :
[en] Suppressors of cytokine signaling (SOCS) are encoded by immediate early genes known to inhibit cytokine responses in a classical feedback loop. SOCS gene expression has been shown to be induced by many cytokines, growth factors, and innate immune stimuli, such as LPS. In this paper, we report that the chemoattractants, IL-8 and fMLP, up-regulate SOCS1 mRNA in human myeloid cells, primary human neutrophils, PBMCs, and dendritic cells. fMLP rapidly up-regulates SOCS1, whereas the induction of SOCS1 upon IL-8 treatment is delayed. IL-8 and fMLP did not signal via Jak/STATs in primary human macrophages, thus implicating the induction of SOCS by other intracellular pathways. As chemoattractant-induced SOCS1 expression in neutrophils may play an important role in regulating the subsequent response to growth promoting cytokines like G-CSF, we investigated the effect of chemoattractant-induced SOCS1 on cytokine signal transduction. We show that pretreatment of primary human neutrophils with fMLP or IL-8 blocks G-CSF-mediated STAT3 activation. This study provides evidence for cross-talk between chemoattractant and cytokine signal transduction pathways involving SOCS proteins, suggesting that these chemotactic factors may desensitize neutrophils to G-CSF via rapid induction of SOCS1 expression.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Stevenson, Nigel J. ✱
HAAN, Serge ✱; Rheinisch - Westfälische Technische Hochschule Aachen - RWTH > Institute for Biochemistry
McClurg, Angela E.
McGrattan, Michael J.
Armstrong, Marilyn A.
Heinrich, Peter C.
Johnston, James A.
✱ These authors have contributed equally to this work.
External co-authors :
yes
Language :
English
Title :
The chemoattractants, IL-8 and formyl-methionyl-leucyl-phenylalanine, regulate granulocyte colony-stimulating factor signaling by inducing suppressor of cytokine signaling-1 expression.