Dectin-1-Targeted Antifungal Liposomes Exhibit Enhanced Efficacy

Area of Science:

• Mycology
• Immunology
• Nanotechnology
• Pharmacology

Background:

• Invasive aspergillosis causes nearly 100,000 deaths annually, with current treatments like amphotericin B (AmB) liposomes (AmB-LLs) having limitations in efficacy and toxicity.
• Existing antifungal therapies offer limited 1-year survival rates (25-60%) for patients with invasive aspergillosis, highlighting the urgent need for improved treatments.
• Dectin-1, a mammalian innate immune receptor, recognizes beta-glucans in fungal cell walls, presenting a potential target for antifungal drug delivery.

Purpose of the Study:

• To develop a novel targeted antifungal liposomal drug delivery system by coating AmB-LLs with the Dectin-1 binding domain.
• To evaluate the binding affinity and antifungal efficacy of the Dectin-1-coated AmB-LLs (DEC-AmB-LLs) against key fungal pathogens.
• To assess the potential of DEC-AmB-LLs to improve upon current antifungal therapeutic strategies.

Main Methods:

• A novel protocol was employed to coat AmB-LLs with the beta-glucan binding domain of Dectin-1, creating DEC-AmB-LLs.
• Binding affinity of DEC-AmB-LLs, untargeted AmB-LLs, and BSA-coated AmB-LLs (BSA-AmB-LLs) to fungal cells was assessed.
• The efficacy of DEC-AmB-LLs in reducing fungal growth and viability was compared to control liposomes using *Aspergillus fumigatus*.

Main Results:

• DEC-AmB-LLs demonstrated rapid, efficient, and strong binding to *Aspergillus fumigatus*, *Candida albicans*, and *Cryptococcus neoformans*.
• Untargeted AmB-LLs and BSA-AmB-LLs exhibited a 200-fold lower affinity for fungal cells compared to DEC-AmB-LLs.
• DEC-AmB-LLs were an order of magnitude more effective than control liposomes in reducing *A. fumigatus* growth and viability, decreasing the effective AmB dose.

Conclusions:

• Dectin-1-targeted liposomal amphotericin B (DEC-AmB-LLs) significantly enhances drug delivery and antifungal activity against major fungal pathogens.
• This targeted approach shows potential for substantially improving the efficacy of antifungal therapeutics by increasing potency and reducing drug toxicity.
• Future research will focus on evaluating pan-antifungal targeted liposomal drugs in preclinical animal models of invasive fungal infections.