Expression of human β‐defensin‐2 in the prostate

What’s known on the subject? and What does the study add? We found the expression of human β‐defensin‐2 (HBD‐2) in the prostate for the first time and LPS, a gram negative bacterial component, upregulated HBD‐2 in prostate epithelial cells. We are looking for other antimicrobial peptides expressed in the prostate besides human β‐defensin‐2. Also, we are studying the relationship between antimicrobial peptides and the development or progression of prostate diseases. OBJECTIVE To investigate the expression and regulation of human β‐defensin‐2 (HBD‐2) in the prostate. PATIENTS AND METHODS Normal human prostate epithelial cell line (RWPE‐1), human prostate cancer cell lines (DU‐145, PC‐3), and paraffin‐embedded prostate tissue from patients with benign prostatic hyperplasia (BPH) were analysed by RT‐PCR and immunohistochemical staining. HBD‐2 expression was also analysed by RT‐PCR and ELISA in RWPE‐1 cells treated with lipopolysaccharide (LPS). Nuclear factor‐κB (NF‐κB) activation was assessed by IκBα immunoblotting and electrophoretic mobility shift assay (EMSA). RESULTS BPH tissue and all of the tested prostate cell lines other than PC‐3 constitutively express HBD‐2 mRNA. HBD‐2 protein was strongly detected in prostate gland tissue surrounded by inflammatory cells including macrophages. Exposure to LPS induced HBD‐2 upregulation and NF‐κB activation, as assessed by IκBα phosphorylation and degradation in RWPE‐1 cells. Bay11‐7082, an NF‐κB inhibitor prevented LPS‐induced HBD‐2 production in RWPE‐1 cells. CONCLUSIONS Prostate epithelial cells may constitutively express HBD‐2, and its expression was upregulated by LPS. Our data indicate that HBD‐2 may be an important immunomodulatory factor in prostate function. Expression of HBD‐2 in normal prostates and the potential role of HBD‐2 in prostatitis and BPH should be addressed in the future.