Restoration of down-regulated PDGF receptors by TGF-beta in human embryonic fibroblasts. Enhanced response during cellular in vitro aging.
The study of [125I]PDGF-BB binding to normal human embryonic lung fibroblasts, quiescent when cultured at sparsity in the presence of minute concentrations of homologous PDS, reveals approximately 2 x 10(5) binding sites for PDGF per cell; this number significantly increases during prolonged quiescence of the culture. As late as 48 h after down-regulation of PDGF receptors, the cells restore only partially their capacity to bind PDGF, with aged cells (above CPD 45) responding more rapidly and efficiently than younger ones. TGF-beta significantly enhances restoration of PDGF receptors and, in aged cells in particular, its presence results in total receptor recovery within 24 h, suggesting a concerted action of PDGF and TGF-beta regulating the proliferation of human fibroblasts in tissue regeneration.
Psarras
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Kletsas
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Stathakos
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D002478:Cells, Cultured; D016922:Cellular Senescence; D015536:Down-Regulation; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008168:Lung; D046911:Macromolecular Substances; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D046911:Macromolecular Substances; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor