Temporomandibular joint synovial fibroblasts mediate serine proteinase dependent Type I collagen degradation

• Published in: Biochimica et biophysica acta Vol. 1760; no. 10; pp. 1521 - 1528
• Main Authors: Song, F., Bergdoll, A.S., Windsor, L.J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2006
• Subjects: alpha 1-Antitrypsin - pharmacology; Cell Line, Tumor; Collagen Degradation; Collagen Type I - metabolism; Culture Media, Conditioned; Fibroblasts - metabolism; Gelatin - metabolism; Humans; Phenanthrolines - pharmacology; Phenylmethylsulfonyl Fluoride - pharmacology; Serine Endopeptidases - metabolism; Serine Proteinase; Synovial Fibroblast; Synovial Membrane - cytology; Synovial Membrane - metabolism; Temporomandibular Joint - metabolism; Trypsin - analysis; Trypsinogen - analysis; Synovial Fibroblast; Collagen Degradation; Serine Proteinase
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2006.05.002

Degenerative temporomandibular joint (TMJ) disorders are characterized by the excessive turnover of collagen. In addition to the matrix metalloproteinase (MMP) and cathepsin mediated collagen degradation pathways, a serine proteinase dependent pathway has recently been identified in TMJ fibroblasts. This study focused on further characterizing this serine proteinase pathway utilizing a media-mediated collagen degradation assay and zymography. The conditioned media from cell-mediated collagen degradation assays were incubated with Type I collagen at pH 7.5 with or without a MMP inhibitor (1,10-phenanthroline), serine proteinase inhibitors (α1-antitrypsin and soybean trypsin inhibitor, STI), or cysteine proteinase inhibitors. The data showed that 1,10-phenanthroline and STI reduced the collagen cleavage by 12.33% and 47.78%, respectively. The cysteine proteinase inhibitors had no effect. The combination of α1-antitrypsin and 1,10-phenanthroline inhibited the cleavage by 79.22%, while STI and 1,10-phenanthroline together blocked the cleavage by 85.44%. Zymography identified a proteinase at approximate 22.5 kDa, which was more effectively blocked by serine proteinase inhibitors than by MMP or cysteine proteinase inhibitors. Reverse transcript-PCR and real-time PCR results demonstrated that TMJ cells did not express trypsinogen-2 mRNA, a collagen cleaving serine proteinase. This study demonstrated that TMJ fibroblasts can predominantly utilize a serine proteinase to mediate collagen degradation, which is not trypsinogen-2.