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The gray mold fungus Botrytis cinerea is a model for necrotrophic plant pathogens due to its wide host range, economic impact, well-assembled genome, and versatile mechanisms for inducing host cell death during colonization. Botrydial and botcinic acid have previously been characterized as major phytotoxins produced by B. cinerea . However, studies from different groups reported variable results regarding the contributions of these phytotoxins to fungal virulence. Here, we demonstrate that botrydial and botcinic acid make a prominent contribution to the full virulence of B. cinerea , by performing infection assays with mutants that are defective in phytotoxin production using different inoculation media. Supplementation by overexpression of distinct cell death-inducing proteins could not restore the full virulence. This work highlights the pivotal roles of these phytotoxins as compared with other virulence factors, as well as the significant impact of inoculation conditions on compatible and incompatible interactions between the fungus and its hosts.

Candida albicans is a commensal yeast that is a common component of the gastrointestinal (GI) microbiome of humans. C. albicans has been shown to bloom in the GI tract of individuals with alcohol use disorder (AUD) and can promote and increase the severity of alcoholic liver disease. However, the effects of C. albicans blooms on the host in the context of AUD or AUD-related phenotypes, such as ethanol preference, have been unstudied. In this work, we report a reduction in ethanol consumption and preference in mice colonized with C. albicans. C. albicans-colonized mice exhibited elevated levels of serum prostaglandin E2 (PGE2), and the reduced ethanol preference was reversed by injection with antagonists of PGE2 receptors. Furthermore, injection of mice with a PGE2 derivative decreased their ethanol preference. These results show that PGE2 acting on its receptors prostaglandin E receptor 1 (EP1) and prostaglandin E receptor 2 (EP2) drives reduced ethanol preference in C. albicans-colonized mice. We also showed altered transcription of dopamine receptors in the dorsal striatum of C. albicans-colonized mice and more rapid acquisition of ethanol-conditioned taste aversion, suggesting alterations to reinforcement or aversion learning. Finally, C. albicans-colonized mice were more susceptible to ethanol-induced motor coordination impairment, showing significant alterations to the behavioral effects of ethanol. This study identifies a member of the fungal microbiome that alters ethanol preference and demonstrates a role for PGE2 signaling in these phenotypes.IMPORTANCECandida albicans is a commensal yeast that is found in the gut of most individuals. C. albicans has been shown to contribute to alcoholic liver disease. Outside of this, the impact of intestinal fungi on alcohol use disorder (AUD) had been unstudied. As AUD is a complex disorder characterized by high relapse rates and there are only three FDA-approved therapies for the maintenance of abstinence, it is important to study novel AUD contributors to find new therapeutic targets. Here, we show that an intestinal fungus, C. albicans, can alter mammalian ethanol consumption through an immune modulator, prostaglandin E2. The results highlight novel contributors to AUD-related phenotypes and further implicate the gut-brain axis in AUD. Future studies could lead to new therapeutic avenues for the treatment of AUD.

Human cytomegalovirus (HCMV) is a master of immune evasion and a potent modulator of the human immune system. The best-characterized mechanism employed by HCMV to suppress host immunity is the production of a viral interleukin-10 homolog (CMVIL-10). While CMVIL-10 is known to suppress immune responses and promote viral persistence, its capacity to promote increased susceptibility to co-infecting pathogens like Aspergillus fumigatus remains unknown. Therefore, we studied the impact of wild-type (WT) HCMV (strain TB40), a CMVIL-10-deficient HCMV mutant (ΔUL111A), and recombinant CMVIL-10 on the immune activity of monocyte-derived dendritic cells (moDCs) during co-infection with A. fumigatus. Using a combination of transcriptomic and phenotypic readouts, our data revealed a strong and time-dependent immuno-paralytic effect of HCMV by suppressing pathogen recognition pathways, cytokine production, DC maturation, and expression of genes that are essential for host defense and tissue repair. Although infection with ΔUL111A lacking CMVIL-10 led to stronger expression of type I interferons, IFN-γ-inducible chemokines, and proinflammatory cytokines than WT infection, interference with antifungal immune defense and fungal clearance during co-infection was largely similar between both strains. The limited effect of CMVIL-10 on antifungal immune defense persisted even after prolonged pre-exposure of DCs to the recombinant virokine. In summary, although CMVIL-10 contributes to shaping an anti-inflammatory environment, HCMV’s suppression of antifungal immunity appears to be multifactorial, with CMVIL-10 alone playing a rather subtle role in altering DC responses to A. fumigatus during viral-fungal co-infection.IMPORTANCEHuman cytomegalovirus (HCMV) is a highly prevalent herpesvirus that establishes lifelong latency and frequently reactivates in immunocompromised individuals, including hematopoietic stem cell transplant recipients. Reactivation not only causes direct disease but also increases the risk of secondary infections, such as invasive pulmonary aspergillosis caused by Aspergillus fumigatus. Specifically, studies estimated that about 6%–25% of critically ill HCMV-positive patients develop HCMV-associated pulmonary aspergillosis. However, the mechanisms by which HCMV creates a permissive environment for fungal superinfection remain poorly understood. HCMV encodes a viral homolog of interleukin-10 (CMVIL-10), which mimics host IL-10 and elicits potent immunomodulatory activity. Here, we show that CMVIL-10 dampens specific anti-viral responses, DC activation, and cytokine signaling. However, HCMV-mediated impairment of fungal control in co-infection settings occurred largely independent of CMVIL-10 expression. These findings suggest that HCMV undermines antifungal defenses through multifactorial mechanisms beyond CMVIL-10, highlighting the need for targeted strategies to restore immune function in high-risk patients.

Candida albicans has been classified by the WHO as a “critical priority” pathogen, highlighting the urgent need for a greater understanding of the mechanisms that enable it to cause disease. C. albicans possesses numerous virulence attributes, but how they synergize during infection is not well understood. Here, using reverse genetics, we dissect the individual and combinatorial roles of four C. albicans virulence factors (Als3p, candidalysin, hyphal growth, and Sap2p) in vitro and in an in vivo murine model of oropharyngeal candidiasis. Increasing the number of C. albicans gene deletions correlated with reduced oral fungal burden, with hyphal growth and candidalysin together being critical for infection, inflammation, and mortality during oropharyngeal infection. These findings demonstrate that virulence attributes act cooperatively as a collective network to promote pathogenicity, a finding also observed in plant fungal pathogens. Our approach has identified specific fungal virulence factors that can be targeted for new treatment strategies against C. albicans infections.

Candida auris is an emerging fungal species, and several reports have recently identified C. auris in patients with vulvovaginal candidiasis (VVC), although few studies have investigated the relationship between C. auris and VVC or the associated host factors. Our study, using the VVC mouse model, confirmed persistent vaginal colonization by C. auris , especially clades I, III, and IV, along with reduced neutrophil infiltration and lower S100A8 secretion under interleukin-17A-deficient conditions. In addition, in vitro assays demonstrated enhanced C. auris adhesion to vaginal epithelial cells, especially microaerobic conditions imitating human vaginal microenvironments. Our findings suggest that C. auris exhibits strong vaginal tropism, and IL-17A plays a critical role in controlling C. auris -associated VVC.

Candida albicans is a common fungal pathogen that causes both mucosal infections, such as thrush, and life-threatening systemic diseases. A key step in infection is the fungus invading epithelial tissues and activating the host epidermal growth factor receptor (EGFR). We discovered that C. albicans alters how EGFR is regulated by inducing its ubiquitination, a modification that leads to receptor degradation. This process depends on two major fungal virulence factors: the adhesin Als3p and Ece1p, the polypeptide that contains the candidalysin toxin. The fungus also broadly increases protein ubiquitination in oral epithelial cells. In a mouse model of oral infection, loss of EGFR in epithelial tissues reduced disease severity, suggesting that the receptor helps the fungus establish infection. These findings reveal a previously unrecognized strategy by which C. albicans manipulates protein ubiquitination and regulation in epithelial cells, offering new insights into fungal pathogenesis and potential therapeutic approaches that target host pathways.

ABSTRACT Fungal infections (mycoses) affect over a billion people per year. Approximately, two million of these infections are life-threatening, especially for patients with a compromised immune system. Fungi of the genera Aspergillus, Candida, Histoplasma and Cryptococcus are opportunistic pathogens that contribute to a substantial number of mycoses. To optimize the diagnosis and treatment of mycoses, we need to understand the complex fungal–host interplay during pathogenesis, the fungal attributes causing virulence and how the host resists infection via immunological defenses. In vitro models can be used to mimic fungal infections of various tissues and organs and the corresponding immune responses at near-physiological conditions. Furthermore, models can include fungal interactions with the host–microbiota to mimic the in vivo situation on skin and mucosal surfaces. This article reviews currently used in vitro models of fungal infections ranging from cell monolayers to microfluidic 3D organ-on-chip (OOC) platforms. We also discuss how OOC models can expand the toolbox for investigating interactions of fungi and their human hosts in the future. From basic to complex: in vitro models to study interactions between human fungal pathogens and their host.

The burden of fungal infections is not widely appreciated. Although these infections are responsible for over one million deaths annually, it is estimated that one billion people are affected by severe fungal diseases. Mycoses of nails and skin, primarily caused by fungi known as dermatophytes, are the most common fungal infections. Trichophyton rubrum appears to be the most common causative agent of dermatophytosis, followed by Trichophyton interdigitale. An estimated 25% of the world’s population suffers from dermatomycosis. Although these infections are not lethal, they compromise the quality of life of infected patients. The outcome of antidermatophytic treatments is impaired by various conditions, such as resistance and tolerance of certain dermatophyte strains. The adage “know your enemy” must be the focus of fungal research. There is an urgent need to increase awareness about the significance of these infections with precise epidemiological data and to improve knowledge regarding fungal biology and pathogenesis, with an emphasis on adaptive mechanisms to tackle adverse conditions from host counteractions. This review outlines the current knowledge about dermatophyte infections, with a focus on signaling pathways required for fungal infection establishment and a broad perspective on cellular and molecular factors involved in antifungal resistance and tolerance.

Zhao et al., from Institute of Quality Standard and Monitoring Technology for Agro-product (Guangdong Academy of Agricultural Sciences), specializing in mycotoxin risk assessment in food systems, revealed novel regulatory mechanisms of aflatoxin biosynthesis in Aspergillus flavus. Satterlee et al., from United States Department of Agriculture Toxicology and Mycotoxin Research Unit, pioneers in fungal chemical ecology, examined the chemical interactions between A. flavus and Fusarium verticillioides, two major maize pathogens. Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Fungal infections in the lungs are lethal complications for those with compromised immune systems and have limited treatment strategies available. These options are restricted further by the increased prevalence of treatment-resistant fungi. Many studies focus on how our immune systems respond to these pathogens, yet airway epithelial cells remain an understudied component of fungal infections in the lungs. Here, the authors provide a transcriptional analysis of primary human airway epithelial cells stimulated by two distinct fungal pathogens, Aspergillus fumigatus and Coccidioides posadasii . These data will enable further mechanistic studies of the contribution of the airway epithelium to initial host responses and represent a powerful new resource for future investigations.