TP53 Codon 72 Polymorphism Impacts Macrophage Activation through Reactive Oxygen Species-Dependent Cell Signaling...

Area of Science:

• Immunology
• Genetics
• Molecular Biology

Background:

• The TP53 gene's common single-nucleotide polymorphism (SNP) at codon 72 influences immune regulation.
• The R72 and P72 variants of TP53 have distinct effects on macrophage activation and inflammatory responses.

Purpose of the Study:

• To investigate the role of the TP53 codon 72 SNP in immune system regulation, particularly in COVID-19 and macrophage activation.
• To elucidate the molecular mechanisms by which TP53 variants affect cellular signaling pathways and immune cell phenotypes.

Main Methods:

• Analysis of TP53 SNP variants (R72 and P72) in relation to immune responses.
• Investigating the impact of R72-p53 on mitochondrial manganese superoxide dismutase and PTEN activity.
• Examining the effects of TP53 variants on PI3K/Akt pathway activation and macrophage polarization (M1/M2).
• Utilizing mouse models for cancer and endotoxemia to assess the in vivo functions of P72 and R72 macrophages.

Main Results:

• The R72 variant promotes an aggravated inflammatory response in COVID-19 patients via biased macrophage activation.
• R72-p53 inhibits superoxide dismutase, leading to PTEN oxidation and PI3K/Akt pathway activation, favoring M2 macrophages.
• P72 macrophages maintain M1 phenotype, reduce tumor growth, and enhance anti-tumor T cell responses.
• P72 macrophages also increased mortality in an endotoxemia model.

Conclusions:

• The TP53 codon 72 SNP significantly impacts macrophage activation, influencing inflammatory and anti-tumor responses.
• Alterations in cell signaling driven by the TP53 SNP may contribute to health disparities, particularly in populations with high P72 frequency like African Americans.
• Understanding these genetic influences is crucial for addressing health disparities in diseases involving dysregulated macrophage activation.