TAp63 determines the fate of oocytes against DNA damage

Area of Science:

• Reproductive Biology
• Oncology
• Cellular Biology

Background:

• Cyclophosphamide and doxorubicin are chemotherapies causing premature ovarian insufficiency (POI).
• The precise oocyte death pathway induced by these agents remains unclear.
• Oocyte sensitivity and survival mechanisms during chemotherapy require further elucidation.

Purpose of the Study:

• To clarify the mechanism of ovarian depletion by cyclophosphamide and doxorubicin.
• To identify key molecular players in chemotherapy-induced oocyte death.
• To explore TAp63 as a potential therapeutic target for ovarian protection.

Main Methods:

• Utilized dormant and activated oocyte models to assess sensitivity to cyclophosphamide.
• Investigated the role of Checkpoint kinase 2 (CHK2) and GNF2 in oocyte protection.
• Employed oocyte-specific Trp63 knockout mice to evaluate TAp63 function in vivo.
• Analyzed molecular markers of apoptosis, including BAX and cPARP.

Main Results:

• Dormant oocytes are more sensitive to cyclophosphamide than activated oocytes.
• CHK2 inhibition, not GNF2, protected oocytes from chemotherapy-induced damage.
• Cyclophosphamide up-regulated p-CHK2 and led to primordial follicle depletion in Abl1 knockout mice.
• TAp63 plays a crucial role in chemotherapy-induced oocyte death, contrary to previous findings.
• Trp63 knockout prevented primordial follicle loss and maintained reproductive function, with reduced BAX and cPARP levels.

Conclusions:

• TAp63 is fundamental in mediating oocyte death signaling in response to DNA damage from chemotherapy.
• Targeting TAp63 represents a promising adjuvant therapy to preserve ovarian reserve during cancer treatment.
• This study provides a mechanistic understanding of ovarian toxicity and a potential strategy to mitigate it.