The Expression of MMP-8 in Human Odontoblasts and Dental Pulp Cells is Down-regulated by TGF-β1

Abstract

Recent findings show that matrix metalloproteinase-8 (MMP-8) is expressed, in addition to neutrophils, by human chondrocytes, cultured fibroblasts, and endothelial cells. We investigated the expression of MMP-8 in other human mesenchyme-derived cells, odontoblasts, and pulp tissue. Odontoblasts and pulp tissue were collected from extracted human teeth for MMP-8 mRNA analysis with reverse-transcription/polymerase chain-reaction (RT-PCR) and Southern blot. The expression, localization, and secretion of MMP-8 protein were studied with Western blot, immunohistochemistry, and immunofluorometric assay. The effect of TGF-beta1 (10 ng/mL) on the expression, secretion, and concentration of secreted MMP-8 was studied by odontoblast and pulp tissue culture methods (Tjäderhane et al., 1998a). RT-PCR demonstrated MMP-8 mRNA expression in native and cultured odontoblasts and pulp tissue and cultured pulp fibroblasts, with a 522-bp transcript comparable with that of bone marrow cells. The specificity of PCR was confirmed with Southern blot. Western blot with MMP-8-specific antibody detected 65- and 50-kDa proteins in native samples, representing latent and active forms of mesenchymal-type MMP-8, and in the conditioned odontoblast culture media, 50-kDa protein was observed. TGF-beta down-regulated the MMP-8 mRNA and concentration of secreted protein in both cultures. Immunohistochemical staining detected MMP-8 in odontoblasts. These findings indicate that mesenchyme-derived cells of the dentin-pulp complex express, synthesize, and activate MMP-8, which may, in concert with odontoblast-derived gelatinases, participate in organization of dentin organic matrix prior to mineralization.

Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

“…High levels of neutrophils and accompanying MMP-8 also correlate with the fibrotic state in patients suffering from hypersensitivity pneumonitis . Other groups have shown that MMP-8 is down-regulated during the course of lung fibrosis (Ruiz et al, 2003), which could be attributed to increased levels of TGF-b, being associated to a decrease of MMP-8 expression (Moilanen et al, 2002;Palosaari et al, 2000). These data indicate that a shift from highly regulated MMP-8 expression to exaggerated, mainly PMN-driven, MMP-8 release might trigger the pathogenesis of fibrosis by disturbing the delicate balance that exists in matrix turnover.…”

Evaluation of plasmatic MMP-8, MMP-9, TIMP-1 and MPO levels in obese and lean women

“…We observed reduced MMP-8 levels in obese women, which may be explained by the negative regulation of MMP-8 expression by biomolecules such as transforming growth factor-beta 1 (TGF-β1) that are elevated in obesity [28] and that strongly downregulate MMP-8 [29], while stimulating MMP-9 expression [30]. To exclude the possibility of decreased MMP-8 levels due to reduced neutrophil activation, we measured the plasma MPO activity.…”

The Role of Host‐derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

“…The odontoblasts in developed human teeth synthesize and release several MMPs, including collagenase-2 (MMP-8) (Palosaari et al, 2000), gelatinases (MMP-2 and -9) (Tjäderhane et al, 1998b), membrane-bound MMP-14 (MT1-MMP) (Palosaari et al, 2002), enamelysin (MMP-20) (Sulkala et al, 2002) and cathepsin D (Linde and Persliden, 1977). The latent and active forms of gelatinolytic species (e.g.…”