Furthermore, it has been shown that adult HSPCs treated with UNC0638 retained stem cell-like phenotypes and function better than the untreated, suggesting a potential application of pharmacological inhibition of G9a in stem cell renewal.
One of two possible models might therefore describe the regenerative response; a selective model, in which specific stem cell progeny are retained within the regenerated area at the expense of others; or a stochastic model, whereby the fraction of retained stem cell progeny within the regenerated tissue is proportional to their initial contribution (Fig. 3).
To determine whether 3 day spheroids, cultured under maintenance conditions alone, retained stem cell markers, we evaluated expression of stem cell markers (CD44, CD133, CD166) and common markers for osteogenic, adipogenic, and chondrogenic differentiation by staining for von Kossa, oil red O, collagen II, and aggrecan, respectively over an additional 10 day period.
Presence of cells that remain undivided for several cell cycles suggests that stem cells in hydra share at least one characteristic of cell cycle regulation with mammalian stem cells, namely the ability to retain stem cells in slow-cycling state.
That study demonstrated that label-retaining mammary epithelial cells are stem cells and that their progeny (transitional cells) are arranged as transitional units, and also demonstrated that both cells express Zonula Occludens-1 and α-catenin proteins, data suggesting that transitional units retain stem cells.
Stem cells possess the capacity to generate two cells of distinct fate upon division: one cell retaining stem cell identity and the other cell destined to differentiate.
Fang, D. D. et al. Expansion of CD133 colon cancer cultures retaining stem cell properties to enable cancer stem cell target discovery.
In mammalian hair, it is unclear how hair follicle stem cells can enter an extended period of quiescence during the resting phase but retain stem cell potential and be subsequently activated for growth.
Mutations and deletions disrupt LZTR1 function, which restrains the self renewal and growth of glioma spheres that retain stem cell features.
The cancer stem cell hypothesis predicts that the chemotherapy-resistant ALDHhigh cells should retain stem cell activity.
