Yeungnam Univ J Med.  2013 Jun;30(1):10-16.

Role of Extracellular Signal-Regulated Kinase 1/2 and Reactive Oxygen Species in Toll-Like Receptor 2-Mediated Dual-Specificity Phosphatase 4 Expression

• Kim SY
• Baek SH

Abstract

BACKGROUND
Toll-like receptors (TLRs) are well-known pattern recognition receptors. Among the 13 TLRs, TLR2 is the most known receptor for immune response. It activates mitogen-activated protein kinases (MAPKs), which are counterbalanced by MAPK phosphatases [MKPs or dual-specificity phosphatases (DUSPs)]. However, the regulatory mechanism of DUSPs is still unclear. In this study, the effect of a TLR2 ligand (TLR2L, Pam3CSK4) on DUSP4 expression in Raw264.7 cells was demonstrated.
METHODS
A Raw264.7 mouse macrophage cell line was cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum and 1% antibiotics (100 U/mL penicillin and 100 g/mL streptomycin) at 37degrees C in 5% CO2. TLR2L (Pam3CSK4)-mediated DUSP4 expressions were confirmed with RT-PCR and western blot analysis. In addition, the detection of reactive oxygen species (ROS) was measured with lucigenin assay.
RESULTS
Pam3CSK4 induced the expression of DUSP1, 2, 4, 5 and 16. The DUSP4 expression was also increased by TLR4 and 9 agonists (lipopolysaccharide and CpG ODN, respectively). Pam3CSK4 also induced ERK1/2 phosphorylation and ROS production, and the Pam3CSK4-induced DUSP4 expression was decreased by ERK1/2 (U0126) and ROS (DPI) inhibitors. U0126 suppressed the ROS production by Pam3CSK4.
CONCLUSION
Pam3CSK4-mediated DUSP4 expression is regulated by ERK1/2 and ROS. This finding suggests the physiological importance of DUSP4 in TLR2-mediated immune response.

Keyword

Toll-like receptor; Dual-specificity phosphatase; ERK1/2; Reactive oxygen species

MeSH Terms

Acridines
Animals
Anti-Bacterial Agents
Blotting, Western
Butadienes
Cell Line
Dual-Specificity Phosphatases
Macrophages
Mice
Mitogen-Activated Protein Kinase Phosphatases
Mitogen-Activated Protein Kinases
Nitriles
Penicillins
Phosphorylation
Phosphotransferases
Reactive Oxygen Species
Receptors, Pattern Recognition
Toll-Like Receptors
Acridines
Anti-Bacterial Agents
Butadienes
Dual-Specificity Phosphatases
Mitogen-Activated Protein Kinase Phosphatases
Mitogen-Activated Protein Kinases
Nitriles
Penicillins
Phosphotransferases
Reactive Oxygen Species
Receptors, Pattern Recognition
Toll-Like Receptors