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Telomerase activity in human hematopoietic progenitor cells
S Hohaus1, M T Voso, E Orta-La Barbera
1Department of Medical Genetics, Università Cattolica S. Cuore, Rome, Italy. stefan_hohaus@krzmail.krz.uni-heidelberg.de
Haematologica
|May 1, 1997
Summary
Hematopoietic stem/progenitor cells expressing CD34 in bone marrow and peripheral blood exhibit telomerase activity. This activity decreases with cell differentiation, indicating telomerase regulation during hematopoiesis.
Area of Science:
- Molecular Biology
- Hematology
- Cell Biology
Background:
- Telomerase stabilizes chromosome ends and is active in germline and malignant cells.
- Its absence in most somatic cells suggests a role in cellular immortality.
- Recent findings indicate telomerase activity in human bone marrow (BM) and peripheral blood (PB).
Purpose of the Study:
- To characterize the specific cell populations expressing telomerase in human BM and PB.
- To investigate the regulation of telomerase activity during hematopoietic cell differentiation and mobilization.
Main Methods:
- Isolation of CD34+ cells from BM and PB.
- In vitro culture of CD34+ cells with growth factors.
- Assessment of telomerase activity using the PCR-based TRAP assay.
Main Results:
- Telomerase activity was primarily localized to the CD34+ hematopoietic progenitor cell fraction in BM and PB.
- CD34+ cells lacking CD33 expression showed higher telomerase activity than CD34+/CD33+ cells.
- In vitro differentiation of CD34+ cells led to decreased telomerase activity, which increased during cytokine-induced PB mobilization.
Conclusions:
- A subset of hematopoietic stem and progenitor cells expresses telomerase.
- Telomerase expression is downregulated during the differentiation of these cells.
- Telomerase activity is dynamically regulated in response to hematopoietic progenitor cell mobilization.