RESUMO
Basic fibroblast growth factor (bFGF) is a multipotential heparin-binding factor that belongs to the fibroblast growth factor (FGF) family. The FGFs demonstrate a wide spectrum of biologic activities in vivo and in vitro. In this study, we investigated the potential of bFGF to regulate the expression of various dermal extracellular matrix proteoglycans and type I collagen mRNAs in cultured human fibroblasts from keloid, which is a prototype of dermal fibrosis, and normal skin tissue. We report that bFGF upregulates the expression of the decorin gene in normal and keloid fibroblasts. In contrast, the expression of biglycan is downregulated by bFGF. The mRNA steady-state level of versican, a large proteoglycan, is not altered by bFGF. Type I collagen gene expression is downregulated substantially in keloid and normal fibroblasts by bFGF. The results suggest that the expression of the proteoglycan genes are uncoordinately regulated and that the gene expression of type I collagen and biglycan is coordinately downregulated. The results also demonstrate that keloid fibroblasts respond similarly as do normal fibroblasts to bFGF in the regulation of proteoglycan and collagen expression.
Assuntos
Proteoglicanas de Sulfatos de Condroitina/genética , Fator 2 de Crescimento de Fibroblastos/farmacologia , Fibroblastos/metabolismo , Proteoglicanas/genética , Biglicano , Células Cultivadas , Proteoglicanas de Sulfatos de Condroitina/metabolismo , Colágeno/genética , Decorina , Proteínas da Matriz Extracelular , Expressão Gênica/efeitos dos fármacos , Humanos , Técnicas In Vitro , Queloide/metabolismo , Lectinas Tipo C , Proteoglicanas/metabolismo , RNA Mensageiro/genética , VersicanasRESUMO
BACKGROUND: Type VII collagen is a minor collagen found in anchoring fibrils. It is expressed predominantly by keratinocytes. In this study, we report the localization and spatial distribution of type VII collagen gene expression in the human umbilical cord, a fetal-derived tissue. EXPERIMENTAL DESIGN: Human umbilical cords were examined in indirect immunofluorescence studies, employing a mouse monoclonal anti-human type VII collagen antibody. Endothelial cells were cultured from the vein and grown on chamber slides for the detection of type VII collagen epitopes. In addition, cultured human umbilical vein cells were analyzed by Northern transfer analysis and by polymerase chain reaction for the expression of the corresponding gene. Fibroblast-like cells were isolated from the Wharton's jelly and were analyzed similarly for type VII collagen expression as well. RESULTS: We demonstrate that type VII collagen is expressed by human umbilical tissue and cells. Indirect immunofluorescence studies demonstrate the presence of type VII collagen epitopes in the epithelium surrounding a connective tissue region known as Wharton's jelly. In addition, there was low but detectable immunofluorescence signal associated with endothelial cells of blood vessels within the umbilical cord. In vitro, the fibroblast-like cells cultured from the Wharton's jelly showed prominent type VII collagen signal. This result was supported by the finding of high level of type VII collagen mRNA in these cells. The human endothelial cells from the vein demonstrated weak but detectable staining for type VII collagen, and the corresponding gene expression was shown by polymerase chain reaction analysis of the mRNA of the endothelial cells. CONCLUSIONS: The results show that umbilical tissue and cells, specifically those from the Wharton's jelly, are relatively enriched in type VII collagen. There is differential spatial localization of this collagen in the fetal tissue. The novel finding is that cells, other than epithelial cells such as keratinocytes, are able to express the type VII collagen gene.
