Pseudolaric Acid B Ameliorates Fungal Keratitis Progression by Suppressing Inflammation and Reducing Fungal Load

Area of Science:

• Ophthalmology
• Mycology
• Immunology

Background:

• Fungal keratitis, particularly Aspergillus fumigatus infections, poses a significant threat to vision.
• Current treatments face challenges with resistance and inflammation management.
• Pseudolaric acid B (PAB) is a natural compound with potential therapeutic properties.

Purpose of the Study:

• To elucidate the antifungal and anti-inflammatory mechanisms of PAB against Aspergillus fumigatus (A. fumigatus) keratitis.
• To investigate PAB's effects on fungal growth, biofilm formation, and host inflammatory responses in vitro and in vivo.

Main Methods:

• In vitro: Minimum Inhibitory Concentration (MIC) assays, crystal violet staining, molecular docking, RT-PCR, Western blot, ELISA.
• In vivo: Mouse model of A. fumigatus keratitis, clinical scoring, fungal load assessment, histological analysis.
• Macrophage polarization analysis using flow cytometry.

Main Results:

• PAB exhibited dose-dependent inhibition of A. fumigatus growth and biofilm formation.
• Molecular docking and RT-PCR confirmed PAB's inhibition of Rho1, crucial for fungal cell wall synthesis.
• In vivo, PAB reduced clinical signs, fungal burden, and macrophage infiltration.
• PAB suppressed inflammatory markers (Mincle, p-Syk, TNF-α, MIP2, iNOS, CCL2) and promoted M2 macrophage polarization.

Conclusions:

• PAB possesses significant antifungal efficacy against A. fumigatus.
• PAB effectively mitigates the inflammatory response in A. fumigatus keratitis by targeting Mincle-Syk pathway and modulating macrophage polarization.
• PAB represents a promising therapeutic agent for fungal keratitis.