Cyclic Antifungal Peptides for Drug-Resistant Invasive Fungal Infections

About This Grant

PROJECT SUMMARY Aspergillosis and Candidiasis, caused primarily by Aspergillus fumigatus and Candida albicans, are the most prevalent invasive fungal infections (IFIs), particularly impacting immunocompromised patients, such as those with HIV/AIDS, cancer, or organ transplant recipients. A. fumigatus and C. albicans are classified as "Critical priority" fungal pathogens by the WHO due to the rise in antifungal drug resistance, especially against the current first-line therapies, such as triazoles for invasive Aspergillosis and echinocandins for Candidiasis. Resistance in these pathogens typically involves mutations in the cyp51A gene in Aspergillus and the ERG11 gene in Candida. This increasing resistance poses a significant threat to global health, emphasizing the urgent need for novel antifungal agents with broad-spectrum activity and innovative mechanisms of action. Despite the grave impact, the development of new antifungal drugs has lagged behind antibacterial drug development, and resistance to existing treatments has become an alarming issue. Our research focuses on developing novel cyclic antifungal peptides (CAFPs) as a promising therapeutic approach to combat these infections. Preliminary studies have identified lead peptides, which effectively inhibit drug-resistant C. albicans and A. fumigatus isolates. These peptides act by disrupting fungal membranes, and they also enhance the efficacy of existing antifungal agents like Fluconazole. The modular structure of these peptides offers the potential for rapid optimization and combination with current therapies, improving efficacy and reducing resistance. We hypothesize that optimizing the charge and hydrophobicity of these peptides will improve their potency, stability, and safety profiles, offering enhanced treatment outcomes for A. fumigatus and C. albicans infections. In Aim 1, we will design a library of new CAFPs based on our lead peptides to investigate their structure-activity relationships, stability, toxicity, and synergy with existing antifungal drugs. In Aim 2, we will assess the in vivo toxicity and efficacy of the top peptides in murine models of invasive pulmonary Aspergillosis and hematogenously disseminated Candidiasis. These studies will determine the safety, pharmacokinetics, and optimal dosing regimens for these peptides. In the R33 Phase, we will refine the most promising CAFPs for preclinical development. This will involve evaluating their pharmacokinetic and pharmacodynamic profiles, optimizing formulations, and testing their efficacy in combination with existing antifungal agents in murine models. We will also use multi-omics approaches to elucidate the mechanism of action of these peptides and their impact on fungal cell function. Our goal is to identify novel antifungal agents that can be used alone or in combination with current therapies to combat resistant fungal infections, ultimately reducing morbidity and mortality associated with invasive Aspergillosis and Candidiasis. This research aims to create potent, broad-spectrum antifungal therapies capable of overcoming current treatment limitations, mitigating resistance, and improving patient outcomes for these life-threatening infections.