Porphyromonas gingivalis stimulates TACE production by T cells.
BACKGROUND
Tumour necrosis factor-alpha converting enzyme (TACE), also known as ADAM17, is a membrane-bound metalloprotease and disintegrin. It is produced by a number of host cells and is known to shed and release cell-bound cytokines, particularly members of the tumour necrosis factor family. The aim of this study was to investigate the effect of Porphyromonas gingivalis on TACE production by a human T-cell line, to identify putative virulence factors involved in this process, and to investigate the effect of doxycycline.


METHODS
P. gingivalis 6-day culture supernatants were used to challenge Jurkat T cells for 6 h. Secreted and cell-associated TACE levels were measured by enzyme-linked immunosorbent assay, whereas messenger RNA expression was investigated by quantitative real-time polymerase chain reaction. To investigate the involvement of cysteine proteases or proteinaceous components in general, P. gingivalis culture supernatants were treated with the specific chemical inhibitor TLCK or heat-inactivated, respectively. The effect of doxycycline on the regulation of TACE secretion by P. gingivalis was also investigated.


RESULTS
P. gingivalis challenge resulted in a concentration-dependent enhancement of TACE messenger RNA expression and protein release by Jurkat cells. TLCK treatment or heat treatment of P. gingivalis culture supernatants decreased TACE release to control levels. Doxycycline inhibited TACE secretion dose dependently.


CONCLUSIONS
The induction of TACE by T cells in response to P. gingivalis may in turn favour the shedding of host cell-bound cytokines into the local microenvironment, potentially amplifying the inflammatory response. In the present experimental system, P. gingivalis cysteine proteases are involved in TACE release by T cells.
Bostanci
N
N
Institute of Dentistry, Barts and The London, Queen Mary's School of Medicine and Dentistry, London, UK.
Reddi
D
D
Rangarajan
M
M
Curtis
M A
MA
Belibasakis
G N
GN
D051722:ADAM Proteins / Q000096:biosynthesis*; D000072198:ADAM17 Protein; D018829:Adhesins, Bacterial / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004318:Doxycycline / Q000494:pharmacology; D015870:Gene Expression; D000080867:Gingipain Cysteine Endopeptidases; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects / Q000201:enzymology* / Q000382:microbiology; D008070:Lipopolysaccharides / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000502:physiology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D014107:Tosyllysine Chloromethyl Ketone / Q000494:pharmacology; D037521:Virulence Factors
D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D017077:Culture Media, Conditioned; D000080867:Gingipain Cysteine Endopeptidases; D008070:Lipopolysaccharides; D011480:Protease Inhibitors; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D037521:Virulence Factors; D014107:Tosyllysine Chloromethyl Ketone; D003546:Cysteine Endopeptidases; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D004318:Doxycycline