TY - JOUR
T1 - IL-18 induces monocyte chemotactic protein-1 production in macrophages through the phosphatidylinositol 3-kinase/Akt and MEK/ERK1/2 pathways
AU - Yoo, Jae Kwang
AU - Kwon, Hyokjoon
AU - Khil, Lee Young
AU - Zhang, Li
AU - Jun, Hee Sook
AU - Yoon, Ji Won
PY - 2005/12/15
Y1 - 2005/12/15
N2 - Macrophages are activated during an inflammatory response and produce multiple inflammatory cytokines. IL-18 is one of the most important innate cytokines produced from macrophages in the early stages of the inflammatory immune response. Monocyte chemoattractant protein (MCP-1) is expressed in many inflammatory diseases such as multiple sclerosis and rheumatoid arthritis, and its expression is correlated with the severity of the disease. Both IL-18 and MCP-1 have been shown to be involved in inflammatory immune responses. However, it has been unclear whether IL-18 is involved in the induction of MCP-1. This investigation was initiated to determine whether IL-18 can induce MCP-1 production, and if so, by which signal transduction pathways. We found that IL-18 induced the production of MCP-1 in macrophages, which was IL-12-independent and was not mediated by autocrine cytokines such as IFN-γ or TNF-α. We then examined signal transduction pathways involved in IL-18-induced MCP-1 production. We found that IL-18 did not activate the IκB kinase/NF-κB pathway, evidenced by no degradation of IκBα and no translocation of NF-κB p65 to the nucleus in IL-18-stimulated macrophages. Instead, IL-18 activated the PI3K/Akt and MEK/ERK1/2 pathways. Inhibition of either of these pathways attenuated MCP-1 production in macrophages, and inhibition of both signaling pathways resulted in the complete inhibition of MCP-1 production. On the basis of these observations, we conclude that IL-18 induces MCP-1 production through the PI3K/Akt and MEK/ERK1/2 pathways in macrophages.
AB - Macrophages are activated during an inflammatory response and produce multiple inflammatory cytokines. IL-18 is one of the most important innate cytokines produced from macrophages in the early stages of the inflammatory immune response. Monocyte chemoattractant protein (MCP-1) is expressed in many inflammatory diseases such as multiple sclerosis and rheumatoid arthritis, and its expression is correlated with the severity of the disease. Both IL-18 and MCP-1 have been shown to be involved in inflammatory immune responses. However, it has been unclear whether IL-18 is involved in the induction of MCP-1. This investigation was initiated to determine whether IL-18 can induce MCP-1 production, and if so, by which signal transduction pathways. We found that IL-18 induced the production of MCP-1 in macrophages, which was IL-12-independent and was not mediated by autocrine cytokines such as IFN-γ or TNF-α. We then examined signal transduction pathways involved in IL-18-induced MCP-1 production. We found that IL-18 did not activate the IκB kinase/NF-κB pathway, evidenced by no degradation of IκBα and no translocation of NF-κB p65 to the nucleus in IL-18-stimulated macrophages. Instead, IL-18 activated the PI3K/Akt and MEK/ERK1/2 pathways. Inhibition of either of these pathways attenuated MCP-1 production in macrophages, and inhibition of both signaling pathways resulted in the complete inhibition of MCP-1 production. On the basis of these observations, we conclude that IL-18 induces MCP-1 production through the PI3K/Akt and MEK/ERK1/2 pathways in macrophages.
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U2 - 10.4049/jimmunol.175.12.8280
DO - 10.4049/jimmunol.175.12.8280
M3 - Article
C2 - 16339568
AN - SCOPUS:29144473003
SN - 0022-1767
VL - 175
SP - 8280
EP - 8286
JO - Journal of Immunology
JF - Journal of Immunology
IS - 12
ER -