Calprotectin expression in vitro by oral epithelial cells confers resistance to infection by Porphyromonas gingivalis.
Calprotectin, an S100 calcium-binding protein with broad-spectrum antimicrobial activity in vitro, is expressed in neutrophils, monocytes, and gingival keratinocytes. In periodontitis, calprotectin appears upregulated and is detected at higher levels in gingival crevicular fluid and tissue specimens. How calprotectin contributes to the pathogenesis of periodontal diseases is unknown. To isolate the effects of calprotectin, a calprotectin-negative oral epithelial cell line was transfected with calprotectin genes to enable expression. Porphyromonas gingivalis was permitted to bind and invade transfected cells expressing calprotectin and sham transfectants. Rates of invasion into both cell lines were compared using the antibiotic protection assay. Transfected cells expressing calprotectin showed 40 to 50% fewer internalized P. gingivalis than sham transfectants. Similarly, binding to calprotectin expressing cells was reduced approximately twofold at all time points (15, 30, 45, and 60 min) as estimated by immunofluorescence analysis. Independent of invasion, however, prolonged exposure to P. gingivalis induced epithelial cell rounding and detachment from the substratum. These morphological changes were delayed, however, in cells expressing calprotectin. Using P. gingivalis protease-deficient mutants, we found that Arg-gingipain and Lys-gingipain contributed to epithelial cell rounding and detachment. In conclusion, expression of calprotectin appears to protect epithelial cells in culture against binding and invasion by P. gingivalis. In addition, cells expressing calprotectin are more resistant to detachment mediated by Arg-gingipain and Lys-gingipain. In periodontal disease, calprotectin may augment both the barrier protection and innate immune functions of the gingival epithelium to promote resistance to P. gingivalis infection.
Nisapakultorn
K
K
Department of Preventive Sciences, School of Dentistry, University of Minnesota, Minneapolis, USA.
Ross
K F
KF
Herzberg
M C
MC
D018829:Adhesins, Bacterial; D001422:Bacterial Adhesion; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology; D000080867:Gingipain Cysteine Endopeptidases; D006388:Hemagglutinins / Q000378:metabolism; D006801:Humans; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000502:physiology; D009061:Mouth Mucosa / Q000166:cytology; D019006:Neural Cell Adhesion Molecules / Q000096:biosynthesis* / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D014407:Tumor Cells, Cultured
D018829:Adhesins, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D006388:Hemagglutinins; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules; D003546:Cysteine Endopeptidases