CXCL-mediated oxidative DNA damage promotes Th2 cytokine responses

Area of Science:

• Immunology
• Molecular Biology
• Toxicology

Background:

• Allergen exposure in the lungs causes DNA damage and upregulates CXC chemokine ligands (CXCLs), contributing to allergic inflammation.
• The exact mechanisms linking DNA damage to immune responses in allergic lung inflammation are not fully understood.

Purpose of the Study:

• To investigate the role of 5-hydroxycytosine (5-OH-Cyt) in CXCL-CXCR1/2 signaling.
• To determine how 5-OH-Cyt influences Th2 immune responses in allergic lung inflammation.

Main Methods:

• Mice were sensitized and challenged with cat dander extract (CDE).
• Lung DNA damage was assessed using markers like γH2AX and pATM.
• CXCL-CXCR1/2 signaling was inhibited using ladarixin.
• Naïve CD4+ T cells were cultured under Th2-skewing conditions with oxidatively damaged DNA bases.

Main Results:

• CDE challenge increased DNA damage markers in the lungs.
• 5-OH-Cyt administration upregulated CXCL1 and CXCL2 in the lungs.
• Ladarixin treatment reduced lung DNA damage and restored genomic integrity.
• Exposure to 5-OH-Cyt and other DNA bases increased Th2 cytokine secretion (IL-4, IL-5, IL-13).

Conclusions:

• 5-hydroxycytosine acts as a damage-associated molecular pattern, driving Th2 responses and exacerbating lung DNA damage.
• A positive feedback loop involving CXCL-mediated signaling amplifies DNA damage and inflammation.
• Inhibition of CXCR1/2 presents a potential therapeutic strategy for allergic lung inflammation and associated DNA damage.