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Physoxia Influences Global and Gene-Specific Methylation in Pluripotent Stem Cells
Fatma Dogan1, Rakad M Kh Aljumaily2, Mark Kitchen1
1The Guy Hilton Research Laboratories, School of Pharmacy and Bioengineering, Faculty of Medicine and Health Sciences, Keele University, Stoke on Trent ST4 7QB, UK.
International Journal of Molecular Sciences
|May 28, 2022
Summary
Physiologic normoxia (physoxia) in pluripotent stem cell (PSC) culture impacts epigenetic marks. Low oxygen conditions reduce DNA methylation and alter gene expression, influencing stemness and cell fate.
Area of Science:
- Stem Cell Biology
- Epigenetics
- Cellular Physiology
Background:
- Pluripotent stem cells (PSCs) have self-renewal and differentiation capacities.
- Culture conditions, including oxygen levels, are critical for maintaining PSC characteristics.
- Physiological normoxia (physoxia) represents low oxygen levels found in human tissues, contrasting with standard air oxygen (21% O2) culture.
Purpose of the Study:
- To investigate the role of physoxia in PSC culture.
- To determine the impact of physoxia on DNA methylation (5mC and 5hmC) and the expression of DNA methyltransferases (DNMTs) and TET enzymes.
- To explore the relationship between oxygen levels, epigenetic modifications, and PSC function.
Main Methods:
- Cultured PSCs under physoxia (low oxygen) and air oxygen (21% O2) conditions.
- Assessed PSC proliferation, metabolic activity, and stemness attributes.
- Quantified DNA methylation levels (5mC and 5hmC) and analyzed the expression of DNMTs (DNMT3B, DNMT3L) and TETs (TET1, TET3), as well as HIF1A and HIF2A.
Main Results:
- Physoxia enhanced PSC proliferation, metabolic activity, and stemness.
- PSCs cultured in physoxia showed significant downregulation of DNMT3B, DNMT3L, TET1, and TET3 compared to air oxygen culture.
- Reduced 5mC and 5hmC levels were observed in physoxia-cultured PSCs, with DNMT3B promoter methylation increasing as its expression decreased.
- HIF1A expression decreased, while HIF2A expression increased under physoxia.
Conclusions:
- Pluripotent stem cells exhibit oxygen-sensitive DNA methylation patterns.
- Physoxia influences the expression of epigenetic regulators like DNMT3B.
- These findings highlight the importance of oxygen microenvironment in regulating PSC epigenetics and function.
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