Activation of matrix metalloproteinase-2 by a novel oral spirochetal species Treponema lecithinolyticum.
BACKGROUND
Periodontal tissue destruction is a characteristic of periodontitis. This can be caused by either bacterial enzymes or host cell-derived matrix metalloproteinases (MMPs). In order to elucidate the etiologic role of oral spirochetes, we investigated the effects of Treponema lecithinolyticum, a novel saccharolytic species, on MMP-2 activation.


METHODS
Gingival fibroblasts (GFs) and periodontal ligament (PDL) cells obtained from healthy human subjects were cultured to confluence in alpha-minimal essential medium (alpha-MEM) supplemented with 10% fetal bovine serum. After serum starvation for a day, the cultures were treated with whole cell sonicates, heat-denatured whole cell sonicates, outer membrane fraction (OMF) or formaldehyde-fixed cells of T. lecithinolyticum. Culture supernatants were collected after incubation for 24 to 48 hours and analyzed for MMP-2 activation by gelatin zymography. Collagenolytic activity was quantitatively measured using human [3H] type IV collagen as a substrate.


RESULTS
Treatment of GFs and PDL cells with whole cell sonicates, formaldehyde-fixed whole cells, or the OMF of T. lecithinolyticum resulted in the production of MMP-2 partly in the fully active form with a molecular mass of 62 kDa, whereas non-treated control cultures and cultures treated with a heat-denatured fraction did not show the active form. Cultures exposed to T. lecithinolyticum had higher collagenolytic activity than non-treated cultures.


CONCLUSIONS
Our results demonstrate that T. lecithinolyticum, possibly mediated by proteinaceous cell surface-associated components, may participate in extracellular matrix degradation by activation of MMP-2 during periodontal inflammation.
Choi
B K
BK
Department of Oral Biology, College of Dentistry and Brain Korea 21 Project of Medical Sciences, Yonsei University, Seoul.
Jung
J H
JH
Suh
H Y
HY
Yoo
Y J
YJ
Cho
K S
KS
Chai
J K
JK
Kim
C K
CK
D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D002417:Cattle; D002478:Cells, Cultured; D024141:Collagen Type IV / Q000378:metabolism; D004396:Coloring Agents; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D005881:Gingiva / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D006801:Humans; D015151:Immunoblotting; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D010513:Periodontal Ligament / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D010518:Periodontitis / Q000382:microbiology; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors; D014208:Treponema / Q000145:classification / Q000201:enzymology*
D001425:Bacterial Outer Membrane Proteins; D024141:Collagen Type IV; D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D020778:Matrix Metalloproteinase 2; C022616:thiazolyl blue