Antisense oligonucleotide of tissue inhibitor of metalloproteinase-1 induces the plasminogen activator activity in periodontal ligament cells.

BACKGROUND

Matrix metalloproteinases (MMPs), produced by both infiltrating and resident cells of the periodontium, play a role in physiologic and pathologic events. It is recognized that an imbalance between activated MMPs and their endogenous inhibitors leads to pathologic breakdown of the extracellular matrix during periodontitis. Although it is known that pro-MMPs are activated by the plasminogen activator (PA)/plasmin system, and that the activated MMPs are inactivated by tissue inhibitor of metalloproteinases (TIMPs), participation of TIMPs in the PA/plasmin system has not been defined.

METHODS

We investigated the effects of the antisense oligonucleotide, consisting of a 21-base sequence from the human TIMP-1 gene including the first ATG initiation codon, on PA/plasmin activities in the cultured medium of periodontal ligament (PDL) fibroblastic cells. Antisense or sense oligonucleotides were directly added into cell-cultured medium, and enzyme activities from the PDL cells were measured.

RESULTS

Antisense TIMP-1 oligonucleotide specifically stimulated the PA activity dose-dependently. Other oligonucleotides, sense TIMP-1 or antisense TIMP-2, did not affect PA activity in PDL cells. The PA activity increased by antisense TIMP-1 oligonucleotide was due to an increase of urokinase-type PA (uPA) protein, but not that of tissue-type PA by means of immunoblotting. Furthermore, the stimulation of PA activity in the conditioned medium by adding antisense oligonucleotide for TIMP-1 was not due to the decreasing levels of PA inhibitor-1, an inhibitor of PA.

CONCLUSIONS

TIMP-1 controls the synthesis of uPA in the PDL cells. Control of the TIMP-uPA system is important in inflammatory periodontal ligament healing.