Low O ₂ tensions and the prevention of differentiation of hES cells

Abstract

Early-stage mammalian embryos develop in a low O2 environment (hypoxia). hES cells, however, are generally cultured under an atmosphere of 21% O2 (normoxia), under which conditions they tend to differentiate spontaneously. Such conditions may not be the most suitable, therefore, for hES cell propagation. Here we have tested two hypotheses. The first hypothesis was that hES cells would grow as well under hypoxic as under normoxic conditions. The second hypothesis was that hypoxic culture would reduce the amount of spontaneous cell differentiation that occurs in hES colonies. Both hypotheses proved to be correct. Cells proliferated as well under 3% and 5% O2 as they did under 21% O2, and growth was only slightly reduced at 1% O2. The appearance of differentiated regions as assessed morphologically, biochemically (by the production of human chorionic gonadotropin and progesterone), and immunohistochemically (by the loss of stage-specific embryonic antigen-4 and Oct-4 and gain of stage-specific embryonic antigen-1 marker expression) was markedly reduced under hypoxic conditions. In addition, hES cell growth under hypoxia provided enhanced formation of embryoid bodies. Hypoxic culture would appear to be necessary to maintain full pluripotency of hES cells.H1 cell ͉ hypoxia ͉ pluripotent ͉ human chorionic gonadotropin ͉ Oct-4 transcription factor

Ex vivo AKT-inhibition facilitates generation of polyfunctional stem cell memory-like CD8+ T cells for adoptive immunotherapy

“…Interestingly, low oxygen levels stabilize and activate HIF, 44 which is important for the maintenance of hematopoietic stem cells and promotes self-renewal of embryonic stem cells. 45,46 Therefore, the enrichment of hypoxia-, HIF1α-targets and hematopoietic stem cell-associated genes in our AKT-inhibited CD8 + T cells could indicate improved self-renewal capacity and good functionality in low oxygen environments.…”

Novel In Vitro Culture Condition Improves the Stemness of Human Dermal Stem/Progenitor Cells

“…According to previous results, oxygen is considered an important biochemical signaling molecule and a major regulator during development (Ezashi et al, 2005). It regulates various cellular events critical to the in vitro growth of cells.…”

Cancer stem cells in glioblastoma—molecular signaling and therapeutic targeting

“…For example, hematopoietic stem cells are maintained in hypoxic niches in bone marrow (Parmar et al, 2007). Interestingly, hypoxia also prevents the differentiation of neural stem cells and promotes the maintenance of self-renewal potential of embryonic stem (ES) cells (Studer et al, 2000;Marrison et al, 2000;Ezashi et al, 2005;Santilli et al, 2010). In addition, restricted oxygen concentrations have been shown to enhance the production of induced pluripotent stem cells (iPSC) (Yoshida et al, 2009).…”