Effects of Oxidative Stress on Mouse Embryonic Stem Cell Proliferation, Apoptosis, Senescence, and Self-Renewal

Abstract

Oxidative stress, associated with either normal metabolism or disease conditions, affects many cellular activities. Most of our knowledge in this fi eld is derived from fully differentiated cells. Embryonic stem cells (ESCs) have attracted enormous attention for their potential applications in cell therapy, but little is known about how the unique properties of ESCs are affected by oxidative stress. We have investigated the effects of oxidative stress induced by H 2 O 2 on several cellular activities of mouse ESCs. Like differentiated cells, ESCs are sensitive to H 2 O 2 -induced apoptosis when continuously exposed to H 2 O 2 at the concentrations above 150 μM. However, unlike differentiated cells, ESCs are resistant to oxidative stress induced senescence. This is demonstrated by the results that when subjected to a short-term sublethal concentration and duration of H 2 O 2 treatment, fi broblasts enter the senescent state with enlarged fl attened cell morphology concurrent with increased expression of senescence marker p21. On the contrary, ESCs neither show any sign of senescence nor express p21. Instead, ESCs enter a transient cell cycle arrest state, but they have remarkable recovery capacity to resume the normal cell proliferation rate without losing the ability of self-renewal and pluripotency. Our results further revealed that H 2 O 2 inhibits cell adhesion and the expression of cyclin D1, which are early events proceeding apoptosis and cell cycle arrest. In conclusion, our data suggest that ESCs are sensitive to H 2 O 2 toxicity, but may have unique mechanisms that prevent H 2 O 2 -induced senescence and protect self-renewal capacity.

Mouse Embryonic Stem Cells Are Deficient in Type I Interferon Expression in Response to Viral Infections and Double-stranded RNA

“…Cell Proliferation, Viability, and Cell Cycle Analysis-Cell proliferation was determined by colony size and by cell number after toluidine blue staining as we described previously (25). The absorbance at 630 nm of toluidine blue-stained cells was measured with a microtiter plate reader.…”

“…Cell cycle analysis by flow cytometry was performed after the cells were stained with 50 g/ml propidium iodide. The cell cycle profiles were generated with the CFlow software (25).…”

Stem cells and the impact of ROS signaling

“…Increased ROS levels in vitro induce only a transient G2/M cell cycle arrest in ESCs, suggesting that ESCs are highly resistant to oxidative stress (Guo et al, 2010a). However, like many other differentiated cells, continuous ROS exposure induces apoptosis in ESCs (Guo et al, 2010a).…”

Mouse Embryonic Stem Cells Have Underdeveloped Antiviral Mechanisms That Can Be Exploited for the Development of mRNA-Mediated Gene Expression Strategy

“…b-actin mRNA was used to normalize relative levels of mRNA for tested genes. The sequences of the primer sets are listed in Supplementary Table S1; Supplementary Data are available online at www.liebertpub.com/scd Cell proliferation, viability, and cell cycle analysis Cell proliferation and viability were determined by cell number and by cell morphology after toluidine blue (TB) staining as we previously described [32]. The absorbance at 630 nm of TB-stained cells was measured with a microtiter plate reader.…”