Controlled conversion of an immortalized mesodermal progenitor cell towards osteogenic, chondrogenic, or adipogenic pathways.

Abstract

Abstract. The teratocarcinoma-derived C1 clone behaves as a mesodermal tripotential progenitor cell whose choice of fate, either osteoblast, chondroblast, or adipoblast, is strictly dependent on the spatial organization of the cells and the nature of the induction. In the absence of cell contact before the addition of inducers, the C1 cells maintain a stable undifferentiated phenotype while expressing potential regulators of embryonic mesodermal stem cell fate such a M-twist and Idl. Upon establishment of cell contacts before the induction of differentiation, the early genes characteristic of the three fates become expressed. In the presence of [3 glycerophosphate and ascorbate, provided the cells have formed aggregates, 95% of the C1 cells mineralize with a kinetics of gene expression close to that of osteoblasts (Poliard, A., D. Lamblin, P. J. Marie, M. H. Buc, and O.Kellermann. 1993. J. Cell Sci. 106:503-512). With 10-6M dexamethasone, 80% of the same aggregates differentiate into loci of chondroblast-like cells. The kinetics of expression of the genes encoding type II, IX, X, and XI collagens, aggrecan and link protein during the conversion towards cartilage hypertrophy resembles that accompanying in vivo chondrogenesis. The synergistic action of dexamethasone and insulin convert most confluent C1 cells into functional adipocytes and induce a pattern of gene expression close to that reported for adipoblast cell lines. The C1 clone with its capacity to differentiate along three alternative pathways with high frequency, therefore appears as a valid in vitro model for deciphering the molecular basis of mesoblast ontogeny.

Overexpression of murine small heat shock protein HSP25 interferes with chondrocyte differentiation and decreases cell adhesion

“…Our results of Northern-blot analysis of C1 aggregates at d0, 12, 26 and 48 ( Figure 7A) confirm previous observations. 33 Collagen I expression, already significant at d0 (lane 1) is maximum at d12 (lane 2), then decreases at d26 and d48 (lanes 3 and 4). Collagen II expression, in contrast, is weak at d0 (lane 1), increases until d26 and then remains high.…”

“…These aggregates continue growing in size during the first 20 days of differentiation but begin to differentiate after inducer treatment (dexamethasone is added at d0). 33 All analysis were performed on aggregates harvested at four different stages: day 0 (d0=induction), 12 (d12), 26 (d26) and 48 (d48).…”

“…This teratocarcinoma-derived cell line 31,32 can, in vitro, be specifically differentiated into chondrocytes, osteocytes or adipocytes according to the inducer used. 33 We have stably transfected C1 undifferentiated cells with an expression vector containing the complete HSP25 cDNA, selected two HSP25 overexpressing clones and studied the cartilage differentiation capacities of these clones. Our results show that HSP25 overexpression disturbs cell adhesion resulting in the alteration of chondrocyte differentiation in the C1 cells.…”

Regulation by Neurotransmitter Receptors of Serotonergic or Catecholaminergic Neuronal Cell Differentiation

“…Due to the low level constitutive expression of the SV40 T antigen, this construct promotes immortalization of neuroectodermal, endodermal, or mesodermal precursor cell lines while still allowing differentiation along multiple pathways to occur (8,9).…”

Embryonic stem cells: a promising tool for cell replacement therapy

“…These include cardiomyocytes, hematopoitic progenitors, yolk sac, skeletal myoctes, smooth muscle cells, adipocytes, hepato- cytes, chondrocytes, endothelial cells, melanocytes, neurons, glia, pancreatic islet cells, primitive endoderm and so on (for review see ref. [15], [16][17][18][19][20][21][22][23][24][25][26][27])…”