Biliverdin Reductase Catalytic Activity Is Essential for Malaria Resistance.

Area of Science:

• Biochemistry
• Immunology
• Malariology

Background:

• Jaundice, indicated by high bilirubin, is an adaptive malaria response.
• Biliverdin reductase A (BVRA) has enzymatic, kinase, and transcription factor functions.
• Disentangling BVRA's catalytic role in malaria is essential.

Purpose of the Study:

• To investigate the role of BVRA's enzymatic activity in malaria protection.
• To determine the contribution of BVRA's catalytic function versus its non-canonical functions.
• To establish a bilirubin concentration threshold for malaria control.

Main Methods:

• Generated Blvra G17A and Blvra E97A mutant mice with reduced BVRA enzymatic activity.
• Assessed malaria susceptibility and survival in wild-type and mutant mice.
• Quantified circulating unconjugated bilirubin levels in all mouse strains.

Main Results:

• Blvra G17A and Blvra E97A mice showed reduced BVRA enzymatic activity and succumbed to malaria.
• Mutant mice failed to reach protective circulating bilirubin levels.
• A dose-response relationship was observed between bilirubin levels and malaria protection.

Conclusions:

• BVRA's antimalarial effect is dependent on its enzymatic activity.
• A minimal bilirubin threshold is required for effective parasite control.
• Findings inform therapeutic strategies and biomarker-guided malaria treatment.