EXPRESSION OF THE PEPTIDE ANTIBIOTIC HUMAN BETA-DEFENSIN-1 IN CULTURED GINGIVAL EPITHELIAL-CELLS AND GINGIVAL TISSUE

Human beta-defensin-1 (hBD-1) is a member of the family of small catio nic antimicrobial peptides that have been identified in several mucosa l epithelia. Because human gingival epithelium is a site that is const antly challenged by oral microorganisms, we examined the expression of hBD-1 in human gingival epithelial and fibroblast cell cultures end t issue samples; Cell cultures were challenged with cell wall extracts o f Porphyromonas gingivalis or Fusobacterium nucleatum, Escherichia col i lipopolysaccharide, tumor necrosis factor alpha, or phorbol myristat e acetate. hBD-1 mRNA was detected in unstimulated and stimulated cult ures by reverse transcription (RT)-PCR using several primer sets speci fic for hBD-1. Gingival epithelial cells, but not gingival fibroblasts , expressed a product of the predicted size for hBD-1 mRNA. The sequen ce of the PCR product was identical to that of hBD-1. hBD-1 mRNA expre ssion was not significantly modulated by any of the stimulants tested. Human gingival tissues from noninflamed and inflamed sites were also analyzed by RT-PCR hBD-1 mRNA was expressed in all tissue samples. The relative expression of hBD-1 mRNA was similar in noninflamed and infl amed tissues obtained from each of four patients undergoing treatment for periodontitis. However, the relative expression of hBD-1 mRNA vari ed ins gingival biopsies obtained from 15 different normal individuals , and the relative hBD-1 expression was unrelated to interleukin-8 exp ression. Our findings show the constitutive expression of hBD-1 mRNA i n cultured epithelial cells and gingival tissues but not gingival fibr oblasts. These findings suggest that expression of hBD-1 may play a ro le as part of the innate host defenses in maintaining normal gingival health.