Transforming growth factor-beta isoforms differently stimulate proalpha2 (I) collagen gene expression during wound healing process in transgenic mice.
The role of many growth factors and cytokines in the process of wound healing has been intensively investigated in recent two decades. Among them, transforming growth factor-betas (TGF-betas) are well known to have a potent stimulatory effect on collagen synthesis as shown in various in vivo experimental systems. In the present study, we examined the effects of various growth factors on the promoter activity of the proalpha2 (I) collagen gene (COL1A2) during the wound healing process. For this purpose, we utilized transgenic mice harboring the -17 kb promoter sequence of the mouse COL1A2 linked to either a firefly luciferase or a bacterial beta-galactosidase gene. These mice exhibited normal phenotypic expression and the wound healing process was not impaired. Full thickness wounds were made by punch biopsy. We examined the effects of TGF-beta1, -beta2, -beta3, basic fibroblast growth factor, platelet-derived growth factor, and connective tissue growth factor by applying them locally to the open wound every 2 days. Among the growth factors examined, all of the three isoforms of TGF- exhibited a more potent stimulatory effect on COL1A2 promoter activity than did other factors. In addition, while TGF-beta1 and -beta2 significantly increased the number of fibroblasts which were positive for X-Gal staining, TGF-beta3 treatment did not change the number of beta-galactosidase expressing cells. Accumulation of collagen fibers was observed to the same extent in the mice treated with TGF-beta1 and those with TGF-beta3. These findings suggest that TGF-beta1 and -beta3 have similar but not identical regulatory mechanisms of COL1A2 expression, and that their pathophysiological roles in wound healing might be different from each other.
Kinbara
Takuro
T
Department of Dermatology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, Japan.
Shirasaki
Fumiaki
F
Kawara
Shigeru
S
Inagaki
Yutaka
Y
de Crombrugghe
Benoit
B
Takehara
Kazuhiko
K
D000818:Animals; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics*; D024042:Collagen Type I; D015870:Gene Expression / Q000187:drug effects*; D006097:Granulation Tissue / Q000502:physiology; D051379:Mice; D008822:Mice, Transgenic; D011347:Procollagen / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000502:physiology; D020033:Protein Isoforms / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D053782:Transforming Growth Factor beta3; D014945:Wound Healing / Q000502:physiology*; D001616:beta-Galactosidase / Q000235:genetics
D024042:Collagen Type I; D011347:Procollagen; D020033:Protein Isoforms; C508961:Tgfb1 protein, mouse; C509045:Tgfb3 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053782:Transforming Growth Factor beta3; D003094:Collagen; D001616:beta-Galactosidase