Difference in gene expression between human fetal liver and adult bone marrow mesenchymal stem cells.

BACKGROUND AND OBJECTIVES Mesenchymal stem cells (MSC) are progenitor cells that are capable of differentiating into mesenchymal tissues. Fetal and adult MSC have similar morphology but differ in proliferative, differentiating and immunosuppressive properties. Further exploring their differences could help in choosing the right source for cellular therapy. DESIGN AND METHODS The gene expression profiles of undifferentiated MSC derived from first trimester fetal liver and adult bone marrow were compared by serial analysis of gene expression, and validated by either reverse transcription polymerase chain reaction or immunoblotting of selected genes. The immunophenotype was compared by flow cytometry and cell ELISA. RESULTS Seventy genes were differentially induced two-fold or more in fetal MSC compared to adult MSC. These involved transcripts regulating germ plasm and limb patterning, brain and early muscle development. Transcripts implicated in cell cycle promotion, chromatin regulation and DNA repair were also more abundant in fetal MSC. Ninety-seven genes were decreased two-fold or more in fetal MSC, including transcripts involved in smooth muscle and keratinocyte differentiation and transcripts for immunological genes. Although phenotypically largely similar, fetal MSC had a higher expression of ICAM1 and contained intracellular deposits of HLA-G while expression of HLA class I and II molecules and VCAM1 was increased in adult MSC. INTERPRETATION AND CONCLUSIONS This study reports the first extensive investigation of the differences in gene expression profiles between fetal and adult MSC. The results suggest that fetal MSC have higher proliferative capacity and are less lineage committed than adult MSC.