Human telomerase catalytic subunit (hTERT)-transfected mesenchymal stem-like cells derived from fetal liver promote ex vivo expansion of hematopoietic stem cells

Fetal liver-derived adherent fibroblast-like stromal cells (FLSCs) were transfected with retrovirus, carrying the human telomerase catalytic subunit (hTERT) gene to establish an immortalized mesenchymal stem-like cell line, designated as FLMSL-hTERT. This cell line had the potential to differentiate into osteocytes and adipocytes. Their immunophenotype was similar with that of mesenchymal stem cells (MSCs) derived from bone marrow (BM), umbilical cord blood, skin, and adipose tissue. The cell line expressed mRNAs of SCF, Wnt5A, FL, KIAA1867, TGF-β, Delta-like, VEGF, SDF-1, PLGF and Jagged-1 that are known to promote hematopoiesis. The FLMSL-hTERT cells could dramatically support cord blood (CB) HSCs/ HPCs expansion ex vivo, especially to maintain HSC properties in vitro at least for 8 wk; moreover, they appeared to be superior to primary human fetal liver stromal cells (FLSCs) in supporting in vitro hematopoiesis, because they were more potent than primary FLSCs in supporting the ex vivo growth of HSC/HPCs during long-term culture. The FLMSL-hTERT cells have been maintained in vitro more than 150 population doublings (PDs) with the unchanged phenotypes. So this cell line may be of value for ex vivo expansion of HSCs/HPCs and for analyzing the human fetal liver hematopoietic microenvironments. © 2007 Nova Science Publishers, Inc.