Fangyan Liu

Azole-resistant Aspergillus fumigatus poses an increasing clinical challenge. In this study, 22 clinical filamentous fungal isolates from southwestern China were preliminarily identified as A. fumigatus based on morphological characteristics, and their antifungal susceptibility was determined using broth microdilution. Three isolates (AF268, AF275 and AF277) exhibiting high-level voriconazole resistance were selected for further phenotypic and molecular characterization. Compared with AF293, the three resistant isolates showed no significant differences in biofilm metabolic activity or biomass, but all exhibited significantly reduced conidiation at 72 h. In a Galleria mellonella infection model, these isolates exhibited attenuated virulence, as indicated by increased larval survival and reduced fungal burdens. All three isolates harbored the cyp51A TR46/Y121F/T289A genotype and shared Hmg1 S212P/Y564F variants, while no Cyp51B substitutions were detected. RT-qPCR analysis further indicated transcriptional dysregulation of ergosterol biosynthesis- and efflux pump-associated genes. These findings show that the three clinical isolates carrying the canonical cyp51A TR46/Y121F/T289A resistance genotype showed differences in biological traits and transcriptional responses relative to the reference strain AF293. The high voriconazole MICs are consistent with the shared cyp51A genotype, whereas the functional significance of the Hmg1 variants and transcriptional changes requires further genetic validation.

Human pathogenic fungi are ubiquitous in the environment and induce an expanding repertoire of devastating diseases globally. Upon fungal invasion, fungus adopt multiple strategies to adapt to, or eliminate, hostile environmental conditions, which immune checkpoints serve as one of the mechanism for fungal evasion. Programmed death receptor-1 (PD-1), an immunosuppressive molecule, transmits inhibitory signals upon binding to its ligand PD-L1. During infection, aberrant activation of the PD-1/PD-L1 pathway has been proven to facilitate immune evasion by the pathogen. In this review, we summarize the roles of PD-1/PD-L1 in fungal infection. First, the molecular structures and function of PD-1 and PD-L1 are described. Then, we highlight the dynamic expression patterns and regulatory mechanisms of PD-1/PD-L1 during fungal invasion. Potential therapeutics based on PD-1/PD-L1-blocking to enhance antifungal immunity and improve clinical outcomes are also discussed. These insights reveal future directions regarding PD-1/PD-L1 and immune checkpoint-based therapies for preventing pathogenic fungi infections.

Background: Invasive pulmonary aspergillosis (IPA) is usually caused by Aspergillus fumigatus infection and associated with high morbidity and mortality in immunocompromised patients. Sodium new houttuyfonate (SNH) has antifungal and immunomodulatory properties, but the therapeutic effect against IPA remains unknown. Methods: The therapeutic effect of SNH in mice with IPA was determined by histopathological analysis and measurements of fungal loads. The toxicity of SNH to mouse alveolar macrophages (MH-S cells) and the changes in phagocytosis ability of MH-S cells to A. fumigatus were determined by cell counting kit-8 (CCK8), microscopic observation, respectively. The biological mechanism of SNH regulating the functional changes of MH-S cells was determined by transcriptomics, real-time quantitative polymerase chain reaction (RT-qPCR), western blot, molecular docking, microRNA sequencing, and miRNA_mRNA interaction analyses. Results: Intraperitoneal injection of SNH had a therapeutic effect in mice with IPA, and 8 μg/mL of SNH was significantly enhanced the ability of MH-S cells to phagocytize and kill A. fumigatus conidia. Moreover, SNH increased antifungal activity of MH-S cells to A. fumigatus via the TLR2/TRAF6/IRF5 and TLR2/TRAF6/ERK axes, respectively. What’s more, SNH inhibited the expression of miR-328-5p and miR-6975-3p in MH-S cells, which negatively regulated TLR2 expression and the phagocytosis and killing functions of MH-S cells. Conclusions: Taken together, these findings clarify the potential immunomodulatory mechanism of SNH for treatment of IPA, suggesting that SNH is effective against A. fumigatus infection.

Rhinosinusitis is a common inflammatory disease of the sinonasal mucosa and paranasal sinuses. The pathogenesis of rhinosinusitis involves a variety of factors, including genetics, nasal microbiota status, infection, and environmental influences. Pathogenic microorganisms, including viruses, bacteria, and fungi, have been proven to target the cilia and/or epithelial cells of ciliated airways, which results in the impairment of mucociliary clearance, leading to epithelial cell apoptosis and the loss of epithelial barrier integrity and immune dysregulation, thereby facilitating infection. However, the mechanisms employed by pathogenic microorganisms in rhinosinusitis remain unclear. Therefore, this review describes the types of common pathogenic microorganisms that cause rhinosinusitis, including human rhinovirus, respiratory syncytial virus, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus species, etc. The damage of mucosal cilium clearance and epithelial barrier caused by surface proteins or secreted virulence factors are summarized in detail. In addition, the specific inflammatory response, mainly Type 1 immune responses (Th1) and Type 2 immune responses (Th2), induced by the entry of pathogens into the body is discussed. The conventional treatment of infectious sinusitis and emerging treatment methods including nanotechnology are also discussed in order to improve the current understanding of the types of microorganisms that cause rhinosinusitis and to help effectively select surgical and/or therapeutic interventions for precise and personalized treatment.

Aspergillus fumigatus is a ubiquitous pathogenic mold and causes several diseases, including mycotoxicosis, allergic reactions, and systemic diseases (inva

Aspergillus fumigatus is a common causative pathogen of aspergillosis. At present, triazole resistance of A. fumigatus poses an important challenge to human health globally. In this study, the biological characteristics and mechanisms of azole resistance of five A. fumigatus strains (AF1, AF2, AF4, AF5, and AF8) were explored. There were notable differences in the sporulation and biofilm formation abilities of the five test strains as compared to the standard strain AF293. The ability of strain AF1 to avoid phagocytosis by MH-S cells was significantly decreased as compared to strain AF293, while that of strains AF2, AF4, and AF5 were significantly increased. Fungal burden analysis with Galleria mellonella larvae revealed differences in pathogenicity among the five strains. Moreover, the broth microdilution and E-test assays confirmed that strains AF1 and AF2 were resistant to itraconazole and isaconazole, while strains AF4, AF5, and AF8 were resistant to voriconazole and isaconazole. Strains AF1 and AF2 carried the cyp51A mutations TR34/L98H/V242I/S297T/F495I combined with the hmg1 mutation S541G, whereas strains AF4 and AF8 carried the cyp51A mutation TR46/Y121F/V242I/T289A, while strain AF5 had no cyp51A mutation. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis revealed differences in the expression levels of genes associated with ergosterol synthesis and efflux pumps among the five strains. In addition, transcriptomics, RT-qPCR, and the NAD⁺/NADH ratio demonstrated that the mechanism of voriconazole resistance of strain AF5 was related to overexpression of genes associated with energy production and efflux pumps. These findings will help to further elucidate the triazole resistance mechanism in A. fumigatus.

With the widespread use of antibiotic drugs worldwide and the global increase in the number of immunodeficient patients, fungal infections have become a se

The morbidity and mortality caused by invasive fungal infections are increasing across the globe due to developments in transplant surgery, the use of immunosuppressive agents, and the emergence of drug-resistant fungal strains, which has led to a challenge in terms of treatment due to the limitations of three classes of drugs. Hence, it is imperative to establish effective strategies to identify and design new antifungal drugs. Drug repurposing is a potential way of expanding the application of existing drugs. Recently, various existing drugs have been shown to be useful in the prevention and treatment of invasive fungi. In this review, we summarize the currently used antifungal agents. In addition, the most up-to-date information on the effectiveness of existing drugs with antifungal activity is discussed. Moreover, the antifungal mechanisms of existing drugs are highlighted. These data will provide valuable knowledge to stimulate further investigation and clinical application in this field. Key points • Conventional antifungal agents have limitations due to the occurrence of drug-resistant strains. • Non-antifungal drugs act as antifungal agents in various ways toward different targets. • Non-antifungal drugs with antifungal activity are demonstrated as effective antifungal strategies.