scholarly journals Antifungal Innate Immunity: A Perspective from the Last 10 Years

2018 ◽  
Vol 10 (5-6) ◽  
pp. 373-397 ◽  
Author(s):  
Fabián Salazar ◽  
Gordon D. Brown
Keyword(s):  
Drug Resistance ◽  
Innate Immunity ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Drug ◽  
Cellular Basis ◽  
Antifungal Drug Resistance ◽  
Life Threatening ◽  
Antifungal Immunity ◽  
New Strategies

Fungal pathogens can rarely cause diseases in immunocompetent individuals. However, commensal and normally nonpathogenic environmental fungi can cause life-threatening infections in immunocompromised individuals. Over the last few decades, there has been a huge increase in the incidence of invasive opportunistic fungal infections along with a worrying increase in antifungal drug resistance. As a consequence, research focused on understanding the molecular and cellular basis of antifungal immunity has expanded tremendously in the last few years. This review will provide an overview of the most exciting recent advances in innate antifungal immunity, discoveries that are helping to pave the way for the development of new strategies that are desperately needed to combat these devastating diseases.

scholarly journals Linking Cellular Morphogenesis with Antifungal Treatment and Susceptibility in Candida Pathogens

2019 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
Jehoshua Sharma ◽  
Sierra Rosiana ◽  
Iqra Razzaq ◽  
Rebecca Shapiro
Keyword(s):  
Drug Resistance ◽  
Candida Species ◽  
Cellular Response ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Health Concern ◽  
Biofilm Growth ◽  
Antifungal Drug Resistance

Fungal infections are a growing public health concern, and an increasingly important cause of human mortality, with Candida species being amongst the most frequently encountered of these opportunistic fungal pathogens. Several Candida species are polymorphic, and able to transition between distinct morphological states, including yeast, hyphal, and pseudohyphal forms. While not all Candida pathogens are polymorphic, the ability to undergo morphogenesis is linked with the virulence of many of these pathogens. There are also many connections between Candida morphogenesis and antifungal drug treatment and susceptibility. Here, we review how Candida morphogenesis—a key virulence trait—is linked with antifungal drugs and antifungal drug resistance. We highlight how antifungal therapeutics are able to modulate morphogenesis in both sensitive and drug-resistant Candida strains, the shared signaling pathways that mediate both morphogenesis and the cellular response to antifungal drugs and drug resistance, and the connection between Candida morphology, drug resistance, and biofilm growth. We further review the development of anti-virulence drugs, and targeting Candida morphogenesis as a novel therapeutic strategy to target fungal pathogens. Together, this review highlights important connections between fungal morphogenesis, virulence, and susceptibility to antifungals.

Progress and prospects for targeting Hsp90 to treat fungal infections

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1127-1137 ◽  
Author(s):  
AMANDA VERI ◽  
LEAH E. COWEN
Keyword(s):  
Drug Resistance ◽  
Anticancer Agents ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Effective Combination ◽  
New Strategy ◽  
Life Threatening ◽  
Hsp90 Chaperone ◽  
Hsp90 Function

SummaryFungal pathogens pose a major threat to human health worldwide. They infect billions of people each year, leading to at least 1·5 million deaths. Treatment of fungal infections is difficult due to the limited number of clinically useful antifungal drugs, and the emergence of drug resistance. A promising new strategy to enhance the efficacy of antifungal drugs and block the evolution of drug resistance is to target the molecular chaperone Hsp90. Pharmacological inhibitors of Hsp90 function that are in development as anticancer agents have potential to be repurposed as agents for combination antifungal therapy for some applications, such as biofilm infections. For systemic infections, however, effective combination therapy regimens may require Hsp90 inhibitors that can selectively target Hsp90 in the pathogen, or alternate strategies to compromise function of the Hsp90 chaperone machine. Selectively impairing Hsp90 function in the pathogen could in principle be achieved by targeting Hsp90 co-chaperones or regulators of Hsp90 function that are more divergent between pathogen and host than Hsp90. Antifungal combination therapies could also exploit downstream effectors of Hsp90 that are critical for fungal drug resistance and virulence. Here, we discuss the progress and prospects for establishing Hsp90 as an important therapeutic target for life-threatening fungal infections.

scholarly journals Tetraploidy accelerates adaption under drug-selection in a fungal pathogen

2021 ◽  
Author(s):  
Ognenka Avramovska ◽  
Emily Rego ◽  
Meleah A Hickman
Keyword(s):  
Drug Resistance ◽  
Genome Size ◽  
Fungal Pathogen ◽  
Fungal Pathogens ◽  
Antifungal Drug ◽  
Drug Selection ◽  
Antifungal Drug Resistance ◽  
Evolutionary Trajectories ◽  
Work Supports ◽  
Initial Genome

AbstractBaseline ploidy significantly impacts evolutionary trajectories, and in particular, tetraploidy has been associated with higher rates of adaptation compared to haploidy and diploidy. While the majority of experimental evolution studies investigating ploidy use Saccharomyces cerivisiae, the fungal pathogen Candida albicans is a powerful system to investigate ploidy dynamics, particularly in the context of antifungal drug resistance. C. albicans laboratory and clinical strains are predominantly diploid, but have also been isolated as haploid and polyploid. Here, we evolved diploid and tetraploid C. albicans for ∼60 days in the antifungal drug caspofungin. Tetraploid-evolved lines adapted faster than diploid-evolved lines and reached higher levels of caspofungin resistance. While diploid-evolved lines generally maintained their initial genome size, tetraploid-evolved lines rapidly underwent genome-size reductions and did so prior to caspofungin adaption. Furthermore, fitness costs in the absence of drug selection were significantly less in tetraploid-evolved lines compared to the diploid-evolved lines. Taken together, this work supports a model of adaptation in which the tetraploid state is transient but its ability to rapidly transition ploidy states improves adaptative outcomes and may drive drug resistance in fungal pathogens.

Antimycotic drugs and their mechanisms of resistance to Candida species

2021 ◽  
Vol 22 ◽  
Author(s):  
Sweety Dahiya ◽  
Namita Sharma ◽  
Aruna Punia ◽  
Pooja Choudhary ◽  
Prity Gulia ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Candida Species ◽  
Molecular Mechanisms ◽  
Fungal Infections ◽  
Treatment Strategies ◽  
Distinct Species ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Success Rates ◽  
Antifungal Drug Resistance

: Fungal infections have shown an upsurge in recent decades, mainly because of the increasing number of immunocompromised patients, and the occurrence of invasive candidiasis is found to be 7-15 folds greater than that of invasive aspergillosis. The genus Candida comprises of more than 150 distinct species; however, only a few of them are found to be pathogenic to humans. Mortality rates of Candida species are found to be around 45%, and the reasons for this intensified mortality are inefficient diagnostic techniques and unfitting initial treatment strategies. There are only a few antifungal drug classes that are employed for the remedy of invasive fungal infections, including azoles, polyenes, echinocandins, and pyrimidine analogs. During the last 2-3 decades, the usage of antifungal drugs has increased several folds, due to which the reports of escalating antifungal drug resistance have also been recorded. The resistance is mostly to the triazole-based compounds. Due to antifungal drug resistance, the success rates of treatment have been reduced and major changes have been observed in the frequency of fungal infections. In this review, we have summarized the major molecular mechanisms for the development of antifungal drug resistance.

scholarly journals Ploidy dynamics and evolvability in fungi

2016 ◽  
Vol 371 (1709) ◽  
pp. 20150461 ◽  
Author(s):  
Noa Blutraich Wertheimer ◽  
Neil Stone ◽  
Judith Berman
Keyword(s):  
Drug Resistance ◽  
Fungal Pathogens ◽  
Large Scale ◽  
Common Property ◽  
Drug Exposure ◽  
Fungal Infections ◽  
Animal Health ◽  
Antifungal Drug ◽  
Health Food ◽  
Stress Survival

Rapid responses to acute stresses are essential for stress survival and are critical to the ability of fungal pathogens to adapt to new environments or hosts. The rapid emergence of drug resistance is used as a model for how fungi adapt and survive stress conditions that inhibit the growth of progenitor cells. Aneuploidy and loss of heterozygosity (LOH), which are large-scale genome shifts involving whole chromosomes or chromosome arms, occur at higher frequency than point mutations and have the potential to mediate stress survival. Furthermore, the stress of exposure to an antifungal drug can induce elevated levels of LOH and can promote the formation of aneuploids. This occurs via mitotic defects that first produce tetraploid progeny with extra spindles, followed by chromosome mis-segregation. Thus, drug exposure induces elevated levels of aneuploidy, which can alter the copy number of genes that improve survival in a given stress or drug. Selection then acts to increase the proportion of adaptive aneuploids in the population. Because aneuploidy is a common property of many pathogenic fungi, including those posing emerging threats to plants, animals and humans, we propose that aneuploid formation and LOH often accompanying it contribute to the rapid generation of diversity that can facilitate the emergence of fungal pathogens to new environmental niches and/or new hosts, as well as promote antifungal drug resistance that makes emerging fungal infections ever more difficult to contain. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’.

scholarly journals Fungal biofilm architecture produces hypoxic microenvironments that drive antifungal resistance

2020 ◽  
Vol 117 (36) ◽  
pp. 22473-22483 ◽  
Author(s):  
Caitlin H. Kowalski ◽  
Kaesi A. Morelli ◽  
Daniel Schultz ◽  
Carey D. Nadell ◽  
Robert A. Cramer
Keyword(s):  
Drug Resistance ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Drug Resistant ◽  
Antifungal Drug Resistance ◽  
Oxygen Gradients ◽  
Biofilm Architecture

Human fungal infections may fail to respond to contemporary antifungal therapies in vivo despite in vitro fungal isolate drug susceptibility. Such a discrepancy between in vitro antimicrobial susceptibility and in vivo treatment outcomes is partially explained by microbes adopting a drug-resistant biofilm mode of growth during infection. The filamentous fungal pathogenAspergillus fumigatusforms biofilms in vivo, and during biofilm growth it has reduced susceptibility to all three classes of contemporary antifungal drugs. Specific features of filamentous fungal biofilms that drive antifungal drug resistance remain largely unknown. In this study, we applied a fluorescence microscopy approach coupled with transcriptional bioreporters to define spatial and temporal oxygen gradients and single-cell metabolic activity withinA. fumigatusbiofilms. Oxygen gradients inevitably arise duringA. fumigatusbiofilm maturation and are both critical for, and the result of,A. fumigatuslate-stage biofilm architecture. We observe that these self-induced hypoxic microenvironments not only contribute to filamentous fungal biofilm maturation but also drive resistance to antifungal treatment. Decreasing oxygen levels toward the base ofA. fumigatusbiofilms increases antifungal drug resistance. Our results define a previously unknown mechanistic link between filamentous fungal biofilm physiology and contemporary antifungal drug resistance. Moreover, we demonstrate that drug resistance mediated by dynamic oxygen gradients, found in many bacterial biofilms, also extends to the fungal kingdom. The conservation of hypoxic drug-resistant niches in bacterial and fungal biofilms is thus a promising target for improving antimicrobial therapy efficacy.

scholarly journals Beauvericin Potentiates Azole Activity via Inhibition of Multidrug Efflux, BlocksC. albicansMorphogenesis, and is Effluxed via Yor1 and Circuitry Controlled by Zcf29

2016 ◽  
pp. AAC.01959-16 ◽  
Author(s):  
Tanvi Shekhar-Guturja ◽  
Walters Aji Tebung ◽  
Harley Mount ◽  
Ningning Liu ◽  
Julia R. Köhler ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Transcription Factor ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Transcriptional Profiling ◽  
Antifungal Drugs ◽  
Multidrug Efflux ◽  
Tor Signaling ◽  
Transcription Factor Genes ◽  
Life Threatening

Invasive fungal infections are a leading cause of human mortality. Effective treatment is hindered by the rapid emergence of resistance to the limited number of antifungal drugs, demanding new strategies to treat life-threatening fungal infections. Here, we explore a powerful strategy to enhance antifungal efficacy using the natural product beauvericin against leading human fungal pathogens. We found that beauvericin potentiates the activity of azole antifungals against azole-resistantCandidaisolates via inhibition of multidrug efflux, and that beauvericin itself is effluxed via Yor1. As observed inSaccharomyces cerevisiae, we determined that beauvericin inhibits TOR signaling inCandida albicans. To further characterize beauvericin activity inC. albicans, we leveraged genome sequencing of beauvericin-resistant mutants. Resistance was conferred by mutations in transcription factor genesTAC1,which is a key regulator of multidrug efflux, andZCF29, which was uncharacterized. Transcriptional profiling and chromatin immunoprecipitation coupled to microarray analyses revealed that Zcf29 binds to and regulates the expression of multidrug transporter genes. Beyond drug resistance, we also discovered that beauvericin blocks theC. albicansmorphogenetic transition from yeast to filamentous growth in response to diverse cues. We found that beauvericin represses the expression of many filament-specific genes, including the transcription factorBRG1. Thus, we illuminate novel circuitry regulating multidrug efflux, and establish that simultaneously targeting drug resistance and morphogenesis provides a promising strategy to combat life-threatening fungal infections.

scholarly journals An insight into new strategies to combat antifungal drug resistance

2018 ◽  
Vol Volume 12 ◽  
pp. 3807-3816 ◽  
Author(s):  
Yan-Hua Zheng ◽  
Yue-Yun Ma ◽  
Yi Ding ◽  
Xie-Qun Chen ◽  
Guang-Xun Gao
Keyword(s):  
Drug Resistance ◽  
Antifungal Drug ◽  
Antifungal Drug Resistance ◽  
Insight Into ◽  
New Strategies
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