Platelet-derived growth factor (PDGF)-BB-mediated induction of monocyte chemoattractant protein 1 (MCP-1) expression involves mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K)/Akt cell signaling pathways. (A) Western blot analysis of time-dependent activation of extracellular-signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), P38 and Akt by PDGF-BB. (B) Inhibition of the ERK, JNK, p38 and Akt pathways by mitogen-activated protein (MAP) kinase kinase (MEK)1/2 (U0126), JNK (SP600125), p38 (SB20358) and PI3K (LY294002) inhibitors resulted in amelioration of PDGF-BB-mediated induction of MCP-1 expression in astrocytes. (C) Transfection with dominant-negative (DN)-MEK but not wild-type (WT)-MEK resulted in abrogation of PDGF-BB-mediated induction of MCP-1. (D) Transduction with DN-Akt but not WT-Akt also resulted in abrogation of PDGF-BB-mediated induction of MCP-1. All the data are presented as mean ± SD of three individual experiments. *P <0.05, **P <0.01, ***P <0.001 versus control group; #P <0.05, ###P <0.001 versus PDGF-BB-treated group.