TGF-β1 stimulates cultured human fibroblasts to proliferate and produce tissue-like fibroplasia: A fibronectin matrix-dependent event

Abstract

During wound repair, fibroblasts accumulate in the injured area until any defect is filled with stratified layers of cells and matrix. Such fibroplasia also occurs in many fibrotic disorders. Transforming growth factor-beta (TGF-beta), a promotor of granulation tissue in vivo and extracellular matrix production in vitro, is expressed during the active fibroplasia of wound healing and fibroproliferative diseases. Under usual tissue culture conditions, normal fibroblasts grow to confluence and then cease proliferation. In this study, culture conditions with TGF-beta 1 have been delineated that promote human fibroblasts to grow in stratified layers mimicking in vivo fibroplasia. When medium supplemented with serum, ascorbate, proline, and TGF-beta was added thrice weekly to normal human dermal fibroblasts, the cells proliferated and stratified up to 16 cell layers thick within the culture dish, producing a tissue-like fibroplasia. TGF-beta stimulated both DNA synthesis as measured by 3H-thymidine uptake and cell proliferation as measured by a Hoechst dye DNA assay in these postconfluent cultures. The stratification was dependent on fibronectin assembly, as demonstrated by anti-fibronectin antibodies which inhibited both basal and TGF-beta-stimulated cell proliferation and stratification. Suppression of collagen matrix assembly in cell layers with beta-amino-proprionitrile (BAPN) did not inhibit basal or TGF-beta stimulated in vitro fibroplasia. BAPN did not interfere with fibronectin matrix assembly as judged by immunofluorescence microscopy. Thus, in concert with serum factors, TGF-beta stimulates postconfluent, fibronectin matrix-dependent, fibroblast growth creating a fibroplasia-like tissue in vitro.

Effects of transforming growth factor-β1 and vascular endothelial growth factor 165 gene transfer on Achilles tendon healing

“…In the present study, the tenocytes proliferation was stimulated by TGF-β and other growth factors provided by the exogenous BMSCs. Besides, the previous study (Clark et al, 1997) also showed that the TGF-β1 induced the proliferation of fibroblasts with the helping of fibronectin. The interaction of TGF-β1 with matrix anchorage may also stimulate the proliferation of fibroblasts.…”

Crucial role of fibroblasts in regulating epidermal morphogenesis

“…At this time point also the presence of other growth factors (KGF, TGF-β, PDGF, or IGF) antagonistically affected the fibroblast-mediated stimulation of keratinocyte proliferation. This finding was quite surprising since these growth factors have been reported to differ in their mechanism of action (reviewed in Moulin 1995) and therefore a diversity in their effects was expected, as reported, for example, for TGF-β1 (Bennett and Schultz 1993;Clark et al 1997;Jiang et al 1995;Rollins et al 1989), IGF-1 ( Barreca et al 1992;Kratz et al 1992;Fig. 5A-C Differential expression of proteins involved in keratinocyte differentiation in epidermis reconstructed on DED matrices containing 0, 4, or 20×10 4 fibroblasts/cm 2 .…”

Collagen triple helix repeat containing-1 inhibits transforming growth factor-β1-induced collagen type I expression in keloid

“…Proliferation of mink lung fibroblasts is stimulated by low concentrations of TGF-b1 (5-10 ng), and inhibited by higher concentrations, 29 whereas cell proliferation of post-confluent cultures of human dermal fibroblasts is stimulated by TGF-b1. 30 Fibroblasts expressing active TGF-b1 proliferated more slowly than either control cells or fibroblasts overexpressing latent TGF-b1. 31 In fact, when cells were grown beyond confluence, only those cells expressing active TGF-b1 formed distinct cell clusters or aggregates.…”