Identification and Functional Analysis of Candidate Genes Regulating Mesenchymal Stem Cell Self‐Renewal and Multipotency

Abstract

Adult human mesenchymal stem cells (hMSCs) possess multilineage differentiation potential, and differentiated hMSCs have recently been shown to have the ability to transdifferentiate into other lineages. However, the molecular signature of hMSCs is not well-known, and the mechanisms regulating their self-renewal, differentiation, and transdifferentiation are not completely understood. In this study, we demonstrate that fully differentiated hMSCs could dedifferentiate, a likely critical step for transdifferentiation. By comparing the global gene expression profiles of undifferentiated, differentiated, and dedifferentiation cells in three mesenchymal lineages (osteogenesis, chondrogenesis, and adipogenesis), we identified a number of "stemness" and "differentiation" genes that might be essential to maintain adult stem cell multipotency as well as to drive lineagespecific commitment. These genes include those that encode cell surface molecules, as well as components of signaling pathways. These genes may be valuable for developing methods to isolate, enrich, and purify homogeneous population of hMSCs and/or maintain and propagate hMSCs as well as guide or regulate their differentiation for gene and cell-based therapy. Using small interfering RNA gene inactivation, we demonstrate that five genes (actin filamentassociated protein, frizzled 7, dickkopf 3, protein tyrosine phosphatase receptor F, and RAB3B) promote cell survival without altering cell proliferation, as well as exhibiting different effects on the commitment of hMSCs into multiple mesenchymal lineages.

Down-regulation of frizzled-7 expression decreases survival, invasion and metastatic capabilities of colon cancer cells

“…This also seems to be consistent with a previous finding that siRNA inhibition of FZD7 decreased the viability of mesenchymal stem cells (hMSCs; Song et al, 2006). However, in contrast to this report, no apoptotic cells were detected in our present experiments as well as in our previous studies (Ueno et al, 2008).…”

“…A major molecular basis for this suppressive effect is thought to be due to the decreased expression of motility-and invasion-related genes, but it is possible that it partly reflects the reduced cell viability. As described above, it was reported that FZD7 promotes cell survival without altering cell proliferation in hMSCs (Song et al, 2006). Furthermore, canonical Wnt signalling was shown to be involved in the regulation of proliferation, as well as the migration/invasion capacity of hMSCs (Neth et al, 2006).…”

“…However, no association was found between FZD7 expression and clinico-pathological factors except for pathological stage. This may be related to the functional diversity of FZD7 including induction of mesenchymal -epithelial transition (Vincan et al, 2007), osteogenic differentiation of hMSCs (Song et al, 2006) and Wnt11 induction of differentiated cell phenotypes (Yamanaka and Nishida, 2007;Kim et al, 2008). We have detected Wnt11 mRNA in seven colon cancer cell lines (data not shown).…”

Defective Myofibroblast Formation from Mesenchymal Stem Cells in the Aging Murine Heart

“…To induce the differentiation process, cells were cultured in the appropriate medium for 21 days. 21 Osteogenesis was detected via histochemical staining of calcium deposits using Alizarin Red S. Adipogenesis was evaluated via the presence of neutral lipids in the cytoplasm stained with Oil Red O and by staining with an anti-perilipin A antibody. To analyze chondrogenic differentiation, sulfated matrix proteoglycans were stained using Alcian Blue.…”

La biologie des cellules souchesmésenchymateuses d’origine humaine

“…Compte tenu de l'homogénéité de la population cellulaire avant toute modification des conditions de culture, il est peu probable que ces résultats s'expliquent par la prolifération de CSM rési-duelles. Il est probable que les transitions passent par un état de dédif-férenciation, des investigateurs ayant montré la capacité des cellules mésenchymateuses différenciées à se dédifférencier lorsqu'on passe d'un milieu de culture différenciant à un milieu de prolifération [29]. La plasticité des CSM constitue un exemple extrême de flexibilité des propriétés des cellules souches [39] (➜).…”