In vitro chondrogenesis of human bone marrow-derived mesenchymal progenitor cells in monolayer culture: activation by transfection with TGF-beta2.

Bone marrow-derived mesenchymal progenitor cells are capable of chondrogenesis, making them a possible source of cells for cartilage tissue engineering. Because of this, we studied the effect of human transforming growth factor beta2 (TGF-beta2) on mesenchymal progenitor cell chondrogenesis in monolayer culture using gene transfection technology. A recombinant pcDNA3.1(+)/TGF-beta2 construct containing a full-length TGF-beta2 from a human placental cDNA library was created through gene cloning and DNA recombination. The construct was then lipofected into mesenchymal progenitor cells isolated from human bone marrow. RT-PCR, Western blotting, and immunohistochemistry analyses were performed to identify the expression of TGF-beta2 and cartilage-associated genes and proteins. The results showed that TGF-beta2 was expressed throughout the culture period. The transfected progenitor cells expressed and produced collagen type II and aggrecan 48 h after transfection, and the expression and synthesis were upregulated after 4 weeks. In contrast, the tested genes and proteins were not detected in non-transfected cells. This shows that transfection of pcDNA3.1(+)/TGF-beta2 into mesenchymal progenitor cells is able to provide transient and persistent expression of cartilage-specific genes and proteins, and suggests that the differentiation of human marrow-derived mesenchymal progenitor cells into chondrocytes in monolayer culture is feasible and may be induced by TGF-beta2. Copyright 2003 Elsevier Science Ltd.