Background:
Background Telomerase activation and human telomerase RNA (hTR) expression are known to be related to the preservation of the ""stemness"" of stem cells. In this study, we have inhibited the expression of hTR to find the relationship between the telomerase activity and differentiation of normal hematopoietic stem cells.
Methods:
We used cord blood collected from 10 full term pregnant women. We classified the CD34+ hematopoietic stem cells from the same donor into three groups: the Ad-OA group was treated with the recombinant adenoviral (Ad) vector Ad-OA using telomerase antisense, the Ad-M6 group was treated with a mutant version of the Ad-OA without telomerase antisense, and a control group without any treatment.
Results:
The mean number of colony-forming cells (CFCs) were 110±38 for the Ad-OA groups, 540±56 for the Ad-M6 groups, and 650±72 for the control groups. Thus, CFCs in the Ad-OA group were lower than in the Ad-M6 group (P＜0.01). The myeloid portion of the CFCs in the Ad-OA group was higher than the Ad-M6 and control groups (P＜0.01). The Ad-OA group showed a higher percentage of granulocytes suggesting more of a tendency for myeloid differentiation than the Ad-M6 and control groups (P＜0.01). We found that the suppression of telomerase activity by the antisense telomerase adenovirus induced the differentiation of hematopoietic stem cells confirmed by differential cell count and cytochemical staining.
Conclusion:
These findings suggest that the activity of the telomerase may play a role in the differentiation of normal CD34+ hematopoietic stem cells into mature cells.

Keywords: Telomerase, Antisense adenovirus, Hematopoietic stem cell, Differentiation