Objective: To establish an immortalized marrow mesenchymal stem cell line to facilitate advances in cartilage engineering research.
Methods: Human telomerase reverse transcriptase (hTERT) cDNA was transferred into primary human marrow mesenchymal stem cells (hMSC) by retroviral vector pLEGFP-C1-hTERT. Subsequently G418 resistant cell clone was screened and expanded for further studies. hMSC biomarkers and hTERT expression were confirmed by examination. Transfected hMSC was induced to differentiate into chondrocyte using TGF-P1 and dexamethasone.
Results: Up-regulated hTERT expression was detected in transfected hMSC. hMSC-hTERT cells could be induced to differentiate into chondrocyte. Higher telomerase activity in transfected cells was maintained for 50 population doublings so far. Collagen II could be detected in induced transfected hMSC by immunocytochemical and hybridization in situ.
Conclusions: Ectopic expression of hTERT can effectively immortalize hMSC in vitro. Immortalized hMSC can be induced to differentiate into chondrocyte under certain condition. It may be an ideal target of further studies in cartilage engineering.