Abstract
Background aims. Human mesenchymal stromal cells (hMSC) play a crucial role in tissue engineering and regenerative medicine, and have important clinical potential for cell therapy. However, many hMSC studies have been restricted by limited cell numbers and difficult detection in vivo. To expand the lifespan, hMSC are usually immortalized by virus-mediated gene transfer. However, these genetically modified cells easily lose critical phenotypes and stable genotypes because of insertional mutagenesis. Methods. We used a non-viral transfection method to establish human telomerase reverse transcriptase-immortalized cord blood hMSC (hTERT-cbMSC). We also established red fluorescent protein (RFP)-expressing hTERT-cbMSC (hTERT/RFP-cbMSC) by the same non-viral transfection method, and these cells were injected into a rat model with traumatic brain injury for in vivo detection analysis. Results. The hTERT-cbMSC could grow more than 200 population doublings with a stable doubling time and maintained differentiation capacities. hTERT/RFP-cbMSC could proliferate efficiently within 2 weeks at the injury location and could be detected easily under a fluorescent microscope. Importantly, both hTERT-cbMSC and hTERT/RFP-cbMSC showed no chromosomal abnormalities by karyotype analysis and no tumor formation in severe combined immunodeficient (SCID) mice by transplantation assay. Conclusions. We have developed immortalized cbMSC with hTERT expression and RFP expression, which will be useful tools for stem cell research and translational study.
Acknowledgments
The authors gratefully acknowledge the financial support of this study by the Food Industry Research and Development Institute, Taiwan (07G291-04) and the Ministry of Economic Affairs, Taiwan (96-EC-17-A-99-R1-0643).
Disclosure of interest: The authors report no potential conflicts of interest. We have already deposited both cell lines in an open-access cell bank of the Bioresource Collection and Research Center, Taiwan, and made them available to public.