Does adenoviral overexpression of Smad-7 and Smad-6 differentially regulate TGF-beta-mediated chondrocyte proliferation and proteoglycan synthesis?
Adenoviral transfection of chondrocytes with Smad-6 and -7 resulted in strong upregulation of Smad-6 and -7 mRNA and protein levels. Furthermore, overexpression of Smad-7 in chondrocytes totally inhibited important TGF-beta-mediated biological responses such as proliferation and PG synthesis, while overexpressed Smad-6 had no or only a partial inhibitory effect on TGF-beta activity. We conclude that in chondrocytes distinct TGF-beta activities are differentially regulated by Smad-6 and Smad-7.
25 years after interruption of asbestos exposure, the expected rapid decline in MM incidence is still lacking, which appears to agree with population-based selection phenomena, with survival of a large pool of asbestos-exposed subjects with minimal exposure.