Construction of eukaryotic expression plasmid of hTGF-β3 and its inducing effect on differentiation of precartilaginous stem cells into chondroblasts.

This study examined the construction of eukaryotic expression plasmid of human transforming growth factor-β3 (hTGF-β3) and its inducing effect on the differentiation of precartilaginous stem cells (PSCs) into chondroblasts. hTGF-β3 gene was amplified by using polymerase chain reaction (PCR) and then inserted into the eukaryotic expression plasmid pcDNA3.1 to construct the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3. Rat PSCs were isolated and purified by employing an immunomagnetic cell sorting system. pcDNA3.1(+)-hTGF-β3 was transfected into purified PSCs with the use of linear polyamines. The expression of TGF-β3 and cartilage-specific extracellular matrix (ECM) components was detected after transfection by real-time quantitative PCR, ELISA, immunochemistry and Western blotting, respectively. The results showed that the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3 was successfully established as identified by enzyme digestion and DNA sequencing. Real-time quantitative PCR and ELISA revealed that hTGF-β3 was strongly expressed in pcDNA3.1(+)-hTGF-β3-transfected PSCs. Real-time quantitative PCR, immunochemistry and Western blotting showed that the cartilage-specific ECM markers, i.e., cartilage oligomeric matrix protein (COMP), Aggrecan, collagen type X and II were intensely expressed in the pcDNA3.1(+)-hTGF-β3-transfected cells. It was concluded that hTGF-β3 could be stably expressed in pcDNA3.1(+)-hTGF-β3-transfected PSCs and induce the differentiation of PSCs into chondroblasts.