In vitro chondrogenesis of human bone marrow-derived mesenchymal progenitor cells in monolayer culture: activation by transfection with TGF-β2

Abstract

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 β2 (TGF-β2) on mesenchymal progenitor cell chondrogenesis in monolayer culture using gene transfection technology. A recombinant pcDNA3.1(+)/TGF-β2 construct containing a full-length TGF-β2 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-β2 and cartilage-associated genes and proteins. The results showed that TGF-β2 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-β2 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-β2.