Exploiting an evolutionary constraint: Targeting TatD nuclease with chrysosplenol D disrupts Mycoplasma gallisepticum...

Area of Science:

• Avian Pathogen Research
• Molecular Biology
• Drug Discovery

Background:

• Mycoplasma gallisepticum (MG) is a significant poultry pathogen impacting global production.
• Nucleases play crucial roles in MG virulence and host-pathogen interactions.
• Current treatments for MG are limited, necessitating novel therapeutic strategies.

Purpose of the Study:

• To investigate the pathogenic role of TatD nuclease in MG.
• To assess the potential of nuclease-targeted therapy against MG infection.
• To identify inhibitors of TatD nuclease for therapeutic development.

Main Methods:

• Computational prediction, site-directed mutagenesis, and bio-layer interferometry (BLI) were used to identify TatD inhibitors.
• In vitro assays assessed TatD nuclease activity and its effects on host cells and DNA/RNA.
• In vivo chick models evaluated the efficacy of chrysosplenol D (CD) in inhibiting MG colonization and reducing disease.

Main Results:

• TatD nuclease degrades host DNA, RNA, and neutrophil extracellular traps (NETs), inducing apoptosis in host cells.
• Chrysosplenol D (CD) was identified as a potent TatD nuclease inhibitor, binding to key residues (Cys158, His157, Asp 211).
• CD treatment blocked TatD activity, inhibited MG colonization in chicks, and ameliorated MG-induced immune dysregulation, oxidative stress, and respiratory damage.

Conclusions:

• Nucleases, exemplified by TatD, are critical virulence factors for Mycoplasma gallisepticum.
• Targeting TatD nuclease with inhibitors like chrysosplenol D represents a promising therapeutic strategy against MG infections.
• TatD nucleases may serve as evolutionarily conserved targets for developing new anti-MG treatments.