97th DOG Annual Meeting 1999
K48
CORNEAL EPITHELIAL AND STROMAL CELLS EXHIBIT DIFFERENT EXPRESSION PATTERNS OF TGF-BETA-RECEPTORS
M. Knorr, P. O. Denk
The function of transforming growth factor-beta during corneal epithelial and stromal wound healing is not been completely understood to date. Currently it is known that cultured human stromal fibroblasts and cultured corneal epithelial cells express the mRNA for TGF-ß-receptor type I and type II. In the present study we investigate the expression of mRNA and protein of TGF-ß-receptors type I, type II and type III in cultured stromal fibroblasts and ex vivo corneal epithelial cells.
Methods: Total cellular RNA and protein were extracted from primary cultures of human stromal fibroblasts and ex vivo corneal epithelial. Reverse-transcription polymerase chain reaction (RT-PCR) was used to detect the expression of mRNA of TGF-ß-receptor type I, type II and type III. Protein expression of the receptors was confirmed by Western Blot.
Results: Amplification products of expected size were detected in cultured human stromal fibroblasts for the mRNA of TGF-ß-receptor type I, type II and type III. In contrast, ex vivo corneal epithelial cells expressed only mRNA of TGF-ß-receptor type III. Corresponding proteins of TGF-receptor type I, type II and type III were detected in cultured human stromal fibroblasts, while corneal epithelial cells expressed only TGF-ß-receptor type III.
Conclusions: The present investigation demonstrates for the first time that all TGF-receptors are expressed on cultured stromal fibroblast but only type III receptor is expressed on ex vivo corneal epithelial cells. Since type III receptor does not participate in the activation of intracellular signalling pathways, it can be concluded, that TGF-beta acts as a type I cytokine during corneal stromal wound healing, promoting keratocyte activation as an epithelial-mesenchymal interaction.
University Eye Clinic, Dep. 1, Schleichstr. 12, D-72076 Tübingen
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