Copper Acts Synergistically With Fluconazole in Candida glabrata by Compromising Drug Efflux, Sterol Metabolism, and Zinc Homeostasis

Regulatory role of the transcription factor BcMr1 in efflux-mediated multidrug resistance in Botrytis cinerea via pre-adaptation to plant secondary metabolites

Botrytis cinerea causes grey mold of many crops and is one of the top ten diseases in agriculture. Its wide host range and high genetic variability make it highly prone to developing fungicide resistance, particularly multidrug resistance (MDR), which is a resistance to various fungicides with different modes of action. We have recently found that B. cinerea adapts to plant secondary metabolites (PSMs) through the up-regulation of efflux protein ATP-binding cassette (ABC) to develop MDR (which is termed e-MDR) in the interaction with host plants. However, how PSM stimulation is transmitted to ABC expression and how MDR is regulated remain unknown. In this study, the transcription factor (TF) BcMr1, which is related to MDR, was screened and identified from various B. cinerea strains having different sensitivities to fungicides through bioinformatic and transcriptomic analyses, accompanied by chromatin immunoprecipitation-sequencing (ChIP-seq), electrophoretic mobility shift assay (EMSA), yeast one-hybrid (Y1H), and quantitative polymerase chain reaction (qPCR). The results revealed that BcMr1 binds to the promoters of ABC transporter genes and positively regulates the expression of BcatrA, BcatrD, BcatrO, Bmr3, BCIN_03g02050 and BCIN_16g02970, which are ABC efflux proteins, resulting in B. cinerea's e-MDR. Furthermore, PSMs and interacting proteins were shown to be possible activators of this TF. This study provides new insights into the regulatory role of the TF BcMr1 and other downstream candidate genes involved in e-MDR in B. cinerea, which helps to understand the development of MDR in the field through pre-adaption mechanism.

Redefining Antifungal Treatment: The Innovation of Metal-Based Compounds

Fungal infections are a significant contributor to global morbidity and mortality, particularly among immunocompromised patients. With the increasing prevalence of drug-resistant strains, it has become imperative to identify alternative approaches. Metal ion coordination enhances drug efficacy through novel modes of action and may hinder resistance mechanisms. This article aims to identify gaps in the current metal-based antifungal therapy to guide research directions and facilitate drug development. Relevant metal complexes, together with their ligands, have been categorized according to their metal coordination and their activities highlighted. Most examples reported were found to be more effective against drug-resistant strains than non-coordinated ligands, thus establishing the importance of metal ion and co-ligand(s) nature, the influence of electron-withdrawing substituents on structure-activity relationships, and the unique structural features of Schiff bases. Although still at the preclinical phase, the in vitro efficacy of these examples suggests that metal-based drugs may represent a promising approach to overcoming antifungal resistance.

Plumbagin inhibits fungal growth, HMGB1/LOX-1 pathway and inflammatory factors in A. fumigatus keratitis

To investigate the anti-inflammatory and antifungal effects of plumbagin (PL) in Aspergillus fumigatus (A. fumigatus) keratitis, the minimum inhibitory concentration (MIC), time-killing curve, spore adhesion, crystal violet staining, calcium fluoride white staining, and Propidium Iodide (PI) staining were employed to assess the antifungal activity of PL in vitro against A. fumigatus. The cytotoxicity of PL was assessed using the Cell Counting Kit-8 (CCK8). The impact of PL on the expression of HMGB1, LOX-1, TNF-α, IL-1β, IL-6, IL-10 and ROS in A. fumigatus keratitis was investigated using RT-PCR, ELISA, Western blot, and Reactive oxygen species (ROS) assay. The therapeutic efficacy of PL against A. fumigatus keratitis was assessed through clinical scoring, plate counting, Immunofluorescence and Hematoxylin-Eosin (HE) staining. Finally, we found that PL inhibited the growth, spore adhesion, and biofilm formation of A. fumigatus and disrupted the integrity of its cell membrane and cell wall. PL decreased IL-6, TNF-α, and IL-1β levels while increasing IL-10 expression in fungi-infected mice corneas and peritoneal macrophages. Additionally, PL significantly attenuated the HMGB1/LOX-1 pathway while reversing the promoting effect of Boxb (an HMGB1 agonist) on HMGB1/LOX-1. Moreover, PL decreased the level of ROS. In vivo, clinical scores, neutrophil recruitment, and fungal burden were all significantly reduced in infected corneas treated with PL. In summary, the inflammatory process can be inhibited by PL through the regulation of the HMGB-1/LOX-1 pathway. Simultaneously, PL can exert antifungal effects by limiting fungal spore adhesion and biofilm formation, as well as causing destruction of cell membranes and walls.

Resurgence and Repurposing of Antifungal Azoles by Transition Metal Coordination for Drug Discovery

Coordination compounds featuring one or more antifungal azole (AA) ligands constitute an interesting family of candidate molecules, given their medicinal polyvalence and the viability of drug complexation as a strategy to improve and repurpose available medications. This review reports the work performed in the field of coordination derivatives of AAs synthesized for medical purposes by discussing the corresponding publications and emphasizing the most promising compounds discovered so far. The resulting overview highlights the efficiency of AAs and their metallic species, as well as the potential still lying in this research area.

Azole potentiation in Candida species

Fungal infections are rising, with over 1.5 billion cases and more than 1 million deaths recorded each year. Among these, Candida infections are frequent in at-risk populations and the rapid development of drug resistance and tolerance contributes to their clinical persistence. Few antifungal drugs are available, and their efficacy is declining due to the environmental overuse and the expansion of multidrug-resistant species. One way to prolong their utility is by applying them in combination therapy. Here, we highlight recently described azole potentiators belonging to different categories: natural, repurposed, or novel compounds. We showcase examples of molecules and discuss their identified or proposed mode of action. We also emphasise the challenges in azole potentiator development, compounded by the lack of animal testing, the overreliance on Candida albicans and Candida auris, as well as the limited understanding of compound efficacy.