PMID- 20138367 OWN - NLM STAT- MEDLINE DCOM- 20100422 LR - 20161125 IS - 1872-9142 (Electronic) IS - 0161-5890 (Linking) VI - 47 IP - 7-8 DP - 2010 Apr TI - Anti-inflammatory actions of Syk inhibitors in macrophages involve non-specific inhibition of toll-like receptors-mediated JNK signaling pathway. PG - 1569-78 LID - 10.1016/j.molimm.2010.01.008 [doi] AB - Toll-like receptors (TLRs) are a major family of pattern recognition receptors (PRRs) and play a crucial role in innate immune system. Even though non-receptor spleen tyrosine kinase (Syk) is a key signaling molecule of immunoreceptor tyrosine-based activation motifs-containing immunoreceptors, its role in TLRs signaling is not clearly understood. Herein, we investigated the role of Syk in TLR-mediated signaling and gene regulation. In bone marrow-derived macrophages (BMDMs) and RAW 264.7 macrophages, treatment of poly(I:C), LPS and CpG, which are specific ligands of TLR3, TLR4 and TLR9, respectively, can increase the mRNA levels of several pro-inflammatory cytokines and mediators, including IFNbeta, TNFalpha, MIP2, IL-6, IL-12beta, iNOS and COX-2. The gene upregulation caused by TLR was inhibited by Syk inhibitor (SykI) and JNK inhibitor (SP600125). Accordingly we found the abilities of TLR3, TLR4 and TLR9 ligands to induce Syk and JNK activation, as evidenced by increased Syk autophosphorylation on Y519/Y520, JNK phosphorylation and both kinase activities. We also found that TLRs-mediated JNK activation, but not IKK, p38 and ERK activation as well as IkappaB degradation in BMDM and RAW 264.7 cells, was blocked by SykI. Nevertheless TLR-mediated JNK activation as well as the increased protein expression of iNOS and COX-2 remained unchanged when Syk protein was knockdown by siRNA approach. With in vitro kinase assay we found two commercial Syk inhibitors (SykI, and BAY61-3606) have direct inhibition on JNK activity. These findings demonstrate that the non-selective action of SykI on JNK should be taken into consideration upon using them to explore the biological actions of Syk. CI - Copyright 2010 Elsevier Ltd. All rights reserved. FAU - Lin, Ying-Cing AU - Lin YC AD - Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan. FAU - Huang, Duen-Yi AU - Huang DY FAU - Chu, Ching-Liang AU - Chu CL FAU - Lin, Wan-Wan AU - Lin WW LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - Mol Immunol JT - Molecular immunology JID - 7905289 RN - 0 (Anti-Inflammatory Agents) RN - 0 (Intracellular Signaling Peptides and Proteins) RN - 0 (Protein Kinase Inhibitors) RN - 0 (RNA, Small Interfering) RN - 0 (Toll-Like Receptors) RN - EC 2.7.10.1 (Protein-Tyrosine Kinases) RN - EC 2.7.10.2 (Syk Kinase) RN - EC 2.7.10.2 (Syk protein, mouse) RN - EC 2.7.11.24 (JNK Mitogen-Activated Protein Kinases) SB - IM MH - Animals MH - Anti-Inflammatory Agents/*pharmacology MH - Cells, Cultured MH - Enzyme Activation/drug effects MH - Gene Expression Regulation/drug effects MH - Intracellular Signaling Peptides and Proteins/*antagonists & inhibitors/genetics/metabolism MH - JNK Mitogen-Activated Protein Kinases/metabolism/pharmacology MH - Macrophages/*drug effects/immunology/*metabolism MH - Mice MH - Mice, Inbred C57BL MH - Protein Kinase Inhibitors/*pharmacology MH - Protein-Tyrosine Kinases/*antagonists & inhibitors/genetics/metabolism MH - RNA, Small Interfering/genetics MH - *Signal Transduction/drug effects MH - Syk Kinase MH - Toll-Like Receptors/immunology/*metabolism EDAT- 2010/02/09 06:00 MHDA- 2010/04/23 06:00 CRDT- 2010/02/09 06:00 PHST- 2009/12/17 00:00 [received] PHST- 2010/01/12 00:00 [revised] PHST- 2010/01/17 00:00 [accepted] PHST- 2010/02/09 06:00 [entrez] PHST- 2010/02/09 06:00 [pubmed] PHST- 2010/04/23 06:00 [medline] AID - S0161-5890(10)00020-9 [pii] AID - 10.1016/j.molimm.2010.01.008 [doi] PST - ppublish SO - Mol Immunol. 2010 Apr;47(7-8):1569-78. doi: 10.1016/j.molimm.2010.01.008.