RPA1 protects DNA damage-induced PANoptosis in limb development

Area of Science:

• Developmental Biology
• Genetics
• Cellular Biology

Background:

• Embryonic development involves rapid cell proliferation, which can compromise genome integrity and lead to birth defects.
• Mechanisms safeguarding genome integrity during embryogenesis, particularly in mesenchymal stem cells, are not fully understood.
• DNA damage response factors are crucial for maintaining genomic stability in rapidly dividing cells.

Purpose of the Study:

• To investigate the role of DNA damage response factors in safeguarding genome integrity during early limb development.
• To elucidate the molecular mechanisms by which RPA1 protects against developmental defects arising from DNA damage.

Main Methods:

• Utilized a conditional knockout mouse model to delete the Rpa1 gene in early limb bud mesenchyme.
• Analyzed DNA damage levels, activation of the cGAS-STING pathway, and Z-DNA accumulation.
• Investigated cell death pathways, specifically PANoptosis, following Rpa1 deletion.

Main Results:

• Conditional knockout of Rpa1 resulted in severe limb malformations (absent forelimbs, underdeveloped hindlimbs).
• Rpa1 deletion led to extensive DNA damage, activating the cGAS-STING pathway and upregulating Zbp1.
• Accumulation of Z-DNA and subsequent ZBP1 activation triggered mesenchymal stem cell death via PANoptosis.

Conclusions:

• RPA1 is essential for maintaining genomic stability during embryonic limb development.
• ZBP1-dependent PANoptosis serves as a critical pathway for eliminating cells with excessive DNA damage during embryogenesis.
• This study highlights a novel mechanism protecting against developmental defects caused by compromised genome integrity.