Beta-Defensin 124 Is Required for Efficient Innate Immune Responses in Prostate Epithelial RWPE-1 Cells

The present study aimed to determine the role played by β-defensin 124 (DEFB124) in the innate immunity of prostate epithelial RWPE-1 cells during bacterial infection.

The expression of DEFB124 was examined by quantitative real-time polymerase chain reaction (PCR), Western blotting, and immunocytochemistry. Enzyme-linked immunosorbent assays and quantitative real-time PCR were performed to determine the production of cytokines and chemokines. Western blotting and chromatin immunoprecipitation studies were performed to assess the interaction between DEFB124 and nuclear factor-kappa B (NF-κB) in peptidoglycan (PGN)-stimulated RWPE-1 cells. By chemotaxis assay, we assessed the effect of DEFB124 on the migration of monocytes.

Exposure to PGN induced DEFB124 upregulation and NF-κB activation through IκBα phosphorylation and IκBα degradation. Bay11-7082, an NF-κB inhibitor, blocked PGN-induced DEFB124 production. Also, NF-κB was shown to be a direct regulator and to directly bind to the -3.14 kb site of the DEFB124 promoter in PGN-treated human prostate epithelial RWPE-1 cells. When DEFB124 was overexpressed in RWPE-1 cells, interestingly, the production of cytokines (interleukin [IL] 6 and IL-12) and chemokines (CCL5, CCL22, and CXCL8) was significantly increased. These DEFB124-upregulated RWPE-1 cells markedly induced chemotactic activity for THP-1 monocytes.

Taken together, these results provide strong evidence for the first time that increased DEFB124 expression via NF-κB activation in PGN-exposed RWPE-1 cells enhances the production of cytokines and chemokines, which may contribute to an efficient innate immune defense.