title: Maintenance of differentiation potential of human bone marrow mesenchymal stem cells immortalized by human telomerase reverse transcriptase gene despite [corrected] extensive proliferation.
abstract: Human bone marrow mesenchymal stem cells (hMSC) represent a population of stem cells that are capable of differentiation into multiple lineages. However, these cells exhibit senescence-associated growth arrest and phenotypic changes during long-term in vitro culture. We have recently demonstrated that overexpression of human telomerase reverse transcriptase (hTERT) in hMSC reconstitutes telomerase activity and extends life span of the cells [Nat. Biotechnol. 20 (2002) 592]. In the present study, we have performed extensive characterization of three independent cell lines derived from the parental hMSC-TERT cell line based on different plating densities during expansion in culture: 1:2 (hMSC-TERT2), 1:4 (hMSC-TERT4), and 1:20 (hMSC-TERT20). The 3 cell lines exhibited differences in morphology and growth rates but they all maintained the characteristics of self-renewing stem cells and the ability to differentiate into multiple mesoderm-type cell lineages: osteoblasts, adipocytes, chondrocytes, and endothelial-like cells over a 3-year period in culture. Also, surface marker studies using flow cytometry showed a pattern similar to that known from normal hMSC. Thus, telomerization of hMSC by hTERT overexpression maintains the stem cell phenotype of hMSC and it may be a useful tool for obtaining enough number of cells with a stable phenotype for mechanistic studies of cell differentiation and for tissue engineering protocols.
authors.affiliation: Laboratory for Molecular Endocrinology, Department of Endocrinology and Metabolism, University Hospital of Odense, Odense, Denmark.
authors.forename: Basem M
authors.initials: BM
authors.lastname: Abdallah
authors.forename: Mandana
authors.initials: M
authors.lastname: Haack-Sørensen
authors.forename: Jorge S
authors.initials: JS
authors.lastname: Burns
authors.forename: Birgitte
authors.initials: B
authors.lastname: Elsnab
authors.forename: Franz
authors.initials: F
authors.lastname: Jakob
authors.forename: Peter
authors.initials: P
authors.lastname: Hokland
authors.forename: Moustapha
authors.initials: M
authors.lastname: Kassem
mesh_terms: D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D004268:DNA-Binding Proteins; D018014:Gene Transfer Techniques; D006801:Humans; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C509186:TERT protein, human; D019098:Telomerase