Engagement of platelet-derived growth factor receptor (PDGF-R) is critical for PDGF-BB induced monocyte chemoattractant protein 1 (MCP-1) expression in astrocytes. (A) Human primary as well as A172 primary astrocytes express both PDGF-α and PDGF-β receptors. Untreated human primary and A172 astrocytes were subjected to flow cytometric analyses using antibodies against human PDGF-αR (CD140α) and PDGF-βR (CD140β). (B,C) PDGF-BB-mediated induction of MCP-1 mRNA and protein expression in human primary and A172 astrocytes. (B) Human primary and A172 astrocytes were exposed to PDGF-BB for 6 h. Total RNA isolated from human A172 astrocytes was subjected to real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis using primers for human MCP-1. (C) Supernatant fluid from astrocytes treated with PDGF-BB for 24 h were assessed for release of chemokine MCP-1 using the human MCP-1 enzyme-linked immunosorbent assay (ELISA) kit. (D) Total RNA from A172 cells transfected with either nonsense (Non) or PDGF-Rβ short interfering (si)RNAs was subjected to RT-PCR analysis using primers specific for PDGF-Rβ. (E) siRNA, but not Non siRNA inhibited PDGF-BB-mediated induction of MCP-1 RNA. (F) Supernatants from A172 cells transfected with either Non or siRNAs were subjected to MCP-1 ELISA assay. PDGF-Rβ siRNA, but not Non siRNA inhibited PDGF-BB-mediated induction of MCP-1 protein. **P <0.01, ***P <0.001 versus control group.