A dual-functioning adenoviral vector encoding both transforming growth factor-β3 and shRNA silencing type I collagen: Construction and controlled release for chondrogenesis

Hyaline articular cartilage degeneration is a common clinical syndrome globally, whereas cell-based therapy has proved to be a good solution to such problems. Given that transforming growth factor (TGF-beta 3) is helpful in maintaining chondrocytic phenotype or stimulating chondrogenic differentiation of stem cells, vectors containing TGF-beta 3 expression cassette can be delivered to therapeutic cells. One problem involved in the application of therapeutic cells in chondrogenesis is the undesirable production of type I collagen in such cells as chondrocytes and synovial mesenchymal stem cells during ex vivo culture, which undermines the mechanical strength of engineered cartilage. RNA interference (RNAi) strategy can be used to knock down its expression to allow better biological and mechanical functions in artificial tissues. In this study, for the first time we report the construction of an adenoviral vector that can express both TGF-beta 3 to promote chondrogenesis and short hairpin RNA (shRNA) targeting type I collagen to block its production. This dual-functioning vector (Ad-dual) Was found to function well in three model cell types: human fibroblast, osteoblast and porcine chondrocyte in terms of the release of TGF-beta 3 protein and down-regulation of type I collagen production. Besides, we also tested its efficacy in Porcine synovial mesenchymal stem cells, highlighting its potential applications in cell-based therapy for the treatment of articular cartilage degeneration. (C) 2009 Elsevier B.V. All rights reserved.