ABSTRACT
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.
ABSTRACT
<p><b>OBJECTIVE</b>To obtain seed cells for cartilage repair through constructing recombinant human transforming growth factor beta3 vector (hTGF-beta3) and transfecting it into rat's precartilaginous stem cells (PSCs).</p><p><b>METHODS</b>Gene engineering technique was introduced to construct eukaryotic expression plasmid pcDNA3.1 (+)-hTGF-beta3. PSCs of rats were isolated and purified with method of immunomagnetic microbeads. Then PSCs were cotransfected with plasmid hTGF-beta3 and pcDNA3.1 (+)-enhanced green fluorescence protein (EGFP) by liner polyethyleneimine (PEI). And 48 hours later the transient expression of EGFP was observed under a fluorescence microscope, and the expression of hTGF-beta3 was detected with reverse transcription-polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>The sequences of the recombinants were consistent with that from Genebank. Cotransfection of EGFP provided fast visual confirmation of successful transduction. The hTGF-beta3 mRNA and protein expression could be detected by RT-PCR and ELISA.</p><p><b>CONCLUSIONS</b>The recombinant plasmid is correctly constructed and successfully transfected into rat's PSCs, which is an important step to treat epiphyseal injury or other osteo-cartilage diseases with transgenic therapy.</p>