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Updated: Aug 13, 2026
Detection of DNA Double-Stranded Breaks in Mouse Oocytes
Published on: June 23, 2023
Molecular requirements for doxorubicin-mediated death in murine oocytes
A Jurisicova1, H-J Lee, S G D'Estaing
1Vincent Center for Reproductive Biology, Vincent Obstetrics and Gynecology Service, Massachusetts General Hospital/Harvard Medical School, Boston, MA 02114, USA.
Abstract:
We previously published evidence that oocytes exposed to doxorubicin (DXR), a widely used chemotherapeutic agent, rapidly undergo morphological and biochemical changes via discrete effector signaling pathways consistent with the occurrence of apoptosis. In this report, we elucidated the molecular requirements for actions of this drug in oocytes. Our results indicate that within 1 h of exposure DXR causes rapid DNA damage, and commits the oocyte to cytoplasmic fragmentation by the fourth hour, followed by delayed oocyte activation and execution of cytoplasmic fragmentation. Inhibitors that interfere with oocyte activation consistently rescue cytoplasmic fragmentation, but fail to suppress DNA damage. There was evidence of depletion of Bax, Caspase-2, MA-3 and Bcl-x transcripts, suggesting that modulations by DXR caused recruitment of these maternal transcripts into the translation process. Furthermore, sphingolipids such as sphingosine-1-phosphate and ceramide modulate DXR actions by, respectively, altering its intracellular trafficking, or by sustaining the drug's contact with DNA.
Insights
Doxorubicin (DXR) causes rapid DNA damage and oocyte fragmentation through specific molecular pathways. While oocyte activation inhibitors prevent fragmentation, they do not prevent DNA damage, highlighting DXR
Area of Science:
- Reproductive biology
- Molecular toxicology
- Cellular signaling
Background:
- Doxorubicin (DXR), a chemotherapy agent, is known to induce apoptosis in oocytes through signaling pathways.
- The precise molecular mechanisms underlying DXR's effects on oocytes require further elucidation.
Purpose of the Study:
- To investigate the molecular requirements for doxorubicin's action in oocytes.
- To understand the temporal sequence of DXR-induced events, including DNA damage and oocyte fragmentation.
Main Methods:
- Exposure of oocytes to doxorubicin (DXR).
- Analysis of DNA damage, cytoplasmic fragmentation, and oocyte activation.
- Assessment of maternal transcript levels (Bax, Caspase-2, MA-3, Bcl-x).
- Investigation of sphingolipid (sphingosine-1-phosphate, ceramide) modulation of DXR effects.
Main Results:
- DXR rapidly induces DNA damage within 1 hour and commits oocytes to cytoplasmic fragmentation by 4 hours.
- Inhibitors of oocyte activation prevent fragmentation but not DNA damage.
- DXR exposure leads to depletion of specific maternal transcripts, suggesting their recruitment into translation.
- Sphingolipids modulate DXR's intracellular trafficking and DNA interaction.
Conclusions:
- DXR initiates oocyte damage through DNA damage, preceding fragmentation and activation.
- Oocyte activation pathways are critical for fragmentation execution but not for initial DNA damage.
- Maternal transcripts and sphingolipids play significant roles in mediating DXR's toxic effects on oocytes.
