Effects of oxygen on mouse embryonic stem cell growth, phenotype retention, and cellular energetics
✍ Scribed by Daryl E. Powers; Jeffrey R. Millman; Ryan B. Huang; Clark K. Colton
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 471 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0006-3592
No coin nor oath required. For personal study only.
✦ Synopsis
Most embryonic stem (ES) cell research is performed with a gas phase oxygen partial pressure (pO 2 ) of 142 mmHg, whereas embryonic cells in early development are exposed to pO 2 values of 0-30 mmHg. To understand effects of these differences, we studied murine ES (mES) growth, maintenance of stem cell phenotype, and cell energetics over a pO 2 range of 0-285 mmHg, in the presence or absence of differentiation-suppressing leukemia inhibitory factor (LIF). With LIF, growth rate was sensitive to pO 2 but constant with time, and expression of self-renewal transcription factors decreased at extremes of pO 2 . Subtle morphological changes suggested some early differentiation, but cells retained the ability to differentiate into derivatives of all three germ layers at low pO 2 . Without LIF, growth rate decreased with time, and self-renewal transcription factor mRNA decreased further. Gross morphological changes occurred, and overt differentiation occurred at all pO 2 . These findings suggested that hypoxia in the presence of LIF promoted limited early differentiation. ES cells survived oxygen starvation with negligible cell death by increasing anaerobic metabolism within 48 h of anoxic exposure. Decreasing pO 2 to 36 mmHg or lower decreased oxygen consumption rate and increased lactate production rate. The fraction of ATP generated aerobically was 60% at or above 142 mmHg and decreased to 0% under anoxia, but the total ATP production rate remained nearly constant at all pO 2 . In conclusion, undifferentiated ES cells adapt their energy metabolism to proliferate at all pO 2 between 0 and 285 mmHg. Oxygen has minimal effects on undifferentiated cell growth and phenotype, but may exert more substantial effects under differentiating conditions.