Functional genomics identifies negative regulatory nodes controlling phagocyte oxidative burst

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• The phagocyte oxidative burst, driven by Nox2 NADPH oxidase, is vital for combating bacterial and fungal infections.
• Impaired Nox2 complex function leads to severe immunodeficiency, and its genetic variants are linked to inflammatory bowel disease (IBD).
• Regulatory mechanisms fine-tuning the oxidative burst remain largely unknown, despite its critical role in host defense.

Purpose of the Study:

• To identify novel regulatory nodes controlling the phagocyte oxidative burst.
• To investigate genes within loci associated with human inflammatory diseases as potential regulators.
• To elucidate the molecular mechanisms underlying oxidative burst regulation.

Main Methods:

• Functional screening of genes linked to human inflammatory disease.
• Multi-omics approach including transcriptional, metabolic, and ubiquitin-cycling analyses.
• Investigated the role of Rnf145 in Nox2 complex proteostasis via ER-associated degradation.

Main Results:

• Discovered Rbpj, Pfkl, and Rnf145 as key regulatory nodes controlling transcriptional, metabolic, and ubiquitin-cycling aspects of the oxidative burst, respectively.
• Demonstrated Rnf145's role in maintaining Nox2 complex proteostasis through endoplasmic reticulum-associated degradation.
• Showed that Rnf145 ablation in macrophages enhances bacterial clearance and corrects oxidative burst defects in Ncf4 haploinsufficient models.

Conclusions:

• Rbpj, Pfkl, and Rnf145 represent critical regulatory nodes for the oxidative burst.
• Rnf145 plays a significant role in Nox2 complex quality control and immune function.
• Targeting these regulators may offer therapeutic strategies for immunodeficiency and inflammatory diseases.