Fate changes leading to multipotency of isolated mesenchymal cells [Expression: Dense_vs_Sparse]

Mesenchymal populations include a fraction of cells exhibiting multipotency as well as others with limited differentiation range. It has been assumed that the mesenchymal cellular cascade is topped by a multipotent cell, which gives rise to progeny with diminishing differentiation potentials. Here we show that cultured mesenchymal cells, a priori exhibiting a limited differentiation potential, may gain new capacities and become multipotent following single cell isolation. These fate changes were accompanied by up-regulation of differentiation promoting genes, many of which also became H4K20me1 methylated. Early events in the process included TGF and Wnt modulation, and down-regulation of hypoxia signaling. Indeed, hypoxic conditions inhibited the observed cell changes. Overall, cell isolation from neighboring partners caused major molecular changes and particularly, a newly established epigenetic state. It is suggested that MSCs behave non-deterministically and non-hierarchically and should therefore be defined primarily by their capacity to undergo fate changes triggered by environmental cues.

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Shoshani O, Ravid O, Massalha H, Aharonov A, Ovadya Y, Pevsner-Fischer M, Leshkowitz D, Zipori D