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J Dermatol Sci. 2003 Apr;31(2):99-109.

Thrombospondin-1 promotes fibroblast-mediated collagen gel contraction caused by activation of latent transforming growth factor beta-1.

Author information

1
Department of Oral and Maxillofacial Surgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, 466-8550, Nagoya, Japan.

Abstract

BACKGROUND:

Grafting of cultured epithelium has become a useful technique for the treatment of epithelial defects, since grafted epithelial cells secrete factors promoting wound healing. We identified one such factor produced by cultured oral epithelial cells as thrombospondin-1 (TSP-1). Recently, TSP-1 was reported to act as an activator of transforming growth factor-beta1 (TGF-beta1).

OBJECTIVE:

The role of TSP-1 in wound healing and its mechanism were investigated in vitro and in vivo.

METHODS:

The cultured oral epithelial cell-conditioned medium was harvested and applied to Heparin-Sepharose affinity chromatography. Proteins were analyzed by N-Terminal sequencer. TSP-1 and the other factors were applied to fibroblasts-mediated collagen gel contraction assay. The amount of TGF-beta1 (latent TGF-beta1 (LTGF) and active TGF-beta1) in collagen gels was quantified by ELISA and Western blotting analysis. Collagen sponges were soaked with TSP-1 and implanted subcutaneously into rats.

RESULTS:

A 38 kDa protein secreted from cultured oral epithelial cells was found to be human TSP-1. TSP-1 promoted collagen gel contraction activity, and anti-human TSP-1 and TGF-beta1 antibody inhibited the activity. The diameters of the gels treated with LTGF and TSP-1 were reduced to a greater extent than those of gels treated with either factor alone. Although there were no significant differences in the amounts of total TGF-beta1, which include LTGF, the amount of 25 kDa TGF-beta1 was 3.30-fold greater in TSP-1-treated samples than controls. In vivo, 7 days after implantation, increased numbers of fibroblasts were observed in the sponges treated with TSP-1.

CONCLUSION:

These findings suggested that TSP-1 causes collagen gel contraction by activation of LTGF. TSP-1 is expected to be especially suitable for regulating wound healing.

PMID:
12670720
[Indexed for MEDLINE]

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