γH2AX in mouse embryonic stem cells: Distribution during differentiation and following γ-irradiation

Tom C Karagiannis; Christian Orlowski; Katherine Ververis; Eleni Pitsillou; Gulcan Sarila; Samuel T Keating; Laura J Foong; Stefanie Fabris; Christina Ngo-Nguyen; Neha Malik; Jun Okabe; Andrew Hung; Theo Mantamadiotis; Assam El-Osta

doi:10.1016/j.cdev.2023.203882

γH2AX in mouse embryonic stem cells: Distribution during differentiation and following γ-irradiation

Cells Dev. 2024 Mar:177:203882. doi: 10.1016/j.cdev.2023.203882. Epub 2023 Nov 11.

Authors

Affiliations

¹ Epigenetics in Human Health and Disease Program, Baker Heart and Diabetes Institute, 75 Commercial Road, Prahran, VIC 3004, Australia; Epigenomic Medicine Laboratory at prospED Training, Carlton, VIC 3053, Australia; Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC 3010, Australia. Electronic address: karat@unimelb.edu.au.
² Epigenetics in Human Health and Disease Program, Baker Heart and Diabetes Institute, 75 Commercial Road, Prahran, VIC 3004, Australia.
³ Epigenomic Medicine Laboratory at prospED Training, Carlton, VIC 3053, Australia; Department of Clinical Pathology, The University of Melbourne, Parkville, VIC 3010, Australia.
⁴ Epigenomic Medicine Laboratory at prospED Training, Carlton, VIC 3053, Australia; School of Science, STEM College, RMIT University, VIC 3001, Australia.
⁵ Epigenomic Medicine Laboratory at prospED Training, Carlton, VIC 3053, Australia.
⁶ School of Science, STEM College, RMIT University, VIC 3001, Australia.
⁷ Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC 3010, Australia; Department of Surgery (RMH), The University of Melbourne, Parkville, VIC 3010, Australia.
⁸ Epigenetics in Human Health and Disease Program, Baker Heart and Diabetes Institute, 75 Commercial Road, Prahran, VIC 3004, Australia; Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia; Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Sha Tin, Hong Kong; Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, The Chinese University of Hong Kong, 3/F Lui Che Woo Clinical Sciences Building, 30-32 Ngan Shing Street, Sha Tin, Hong Kong; Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong; Biomedical Laboratory Science, Department of Technology, Faculty of Health, University College Copenhagen, Copenhagen, Denmark.

PMID: 37956740
DOI: 10.1016/j.cdev.2023.203882

Abstract

Phosphorylated histone H2AX (γH2AX) represents a sensitive molecular marker of DNA double-strand breaks (DSBs) and is implicated in stem cell biology. We established a model of mouse embryonic stem cell (mESC) differentiation and examined the dynamics of γH2AX foci during the process. Our results revealed high numbers of γH2AX foci in undifferentiated mESCs, decreasing as the cells differentiated towards the endothelial cell lineage. Notably, we observed two distinct patterns of γH2AX foci: the typical discrete γH2AX foci, which colocalize with the transcriptionally permissive chromatin mark H3K4me3, and the less well-characterized clustered γH2AX regions, which were only observed in intermediate progenitor cells. Next, we explored responses of mESCs to γ-radiation (¹³⁷Cs). Following exposure to γ-radiation, mESCs showed a reduction in cell viability and increased γH2AX foci, indicative of radiosensitivity. Despite irradiation, surviving mESCs retained their differentiation potential. To further exemplify our findings, we investigated neural stem progenitor cells (NSPCs). Similar to mESCs, NSPCs displayed clustered γH2AX foci associated with progenitor cells and discrete γH2AX foci indicative of embryonic stem cells or differentiated cells. In conclusion, our findings demonstrate that γH2AX serves as a versatile marker of DSBs and may have a role as a biomarker in stem cell differentiation. The distinct patterns of γH2AX foci in differentiating mESCs and NSPCs provide valuable insights into DNA repair dynamics during differentiation, shedding light on the intricate balance between genomic integrity and cellular plasticity in stem cells. Finally, the clustered γH2AX foci observed in intermediate progenitor cells is an intriguing feature, requiring further exploration.

Keywords: DNA-damage; Sca-1(+) progenitor; Stem cell differentiation; mESCs; γH2AX.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cell Differentiation / genetics
DNA Breaks, Double-Stranded
DNA Repair* / genetics
Embryonic Stem Cells
Mice
Mouse Embryonic Stem Cells*