scholarly journals Essential Role for the Phosphatidylinositol 3,5-Bisphosphate Synthesis Complex in Caspofungin Tolerance and Virulence in Candida glabrata

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Deepak Kumar Choudhary ◽  
Priyanka Bhakt ◽  
Rupinder Kaur
Keyword(s):  
Cell Wall ◽  
Candida Glabrata ◽  
Scaffolding Protein ◽  
Pathogenic Yeast ◽  
Lipid Kinase ◽  
Lipid Molecule ◽  
Content Type ◽  
Phosphoinositide Signaling ◽  
Promising Target ◽  
Opportunistic Fungal Pathogen

ABSTRACT Increasing resistance of the human opportunistic fungal pathogen Candida glabrata toward the echinocandin antifungals, which target the cell wall, is a matter of grave clinical concern. Echinocandin resistance in C. glabrata has primarily been associated with mutations in the β-glucan synthase-encoding genes C. glabrata FKS1 (CgFKS1) and CgFKS2. This notwithstanding, the role of the phosphoinositide signaling in antifungal resistance is just beginning to be deciphered. The phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] is a low-abundance lipid molecule that is pivotal to the intracellular membrane traffic. Here, we demonstrate for the first time that the PI(3,5)P2 kinase CgFab1, along with its activity regulator CgVac7 and the scaffolding protein CgVac14, is required for maintenance of the cell wall chitin content, survival of the cell wall, and caspofungin stress. Further, deletion analyses implicated the PI(3,5)P2 phosphatase CgFig4 in the regulation of PI(3,5)P2 levels and azole and echinocandin tolerance through CgVac14. We also show the localization of the CgFab1 lipid kinase to the vacuole to be independent of the CgVac7, CgVac14, and CgFig4 proteins. Lastly, our data demonstrate an essential requirement for PI(3,5)P2 signaling components, CgFab1, CgVac7, and CgVac14, in the intracellular survival and virulence in C. glabrata. Altogether, our data have yielded key insights into the functions and metabolism of PI(3,5)P2 lipid in the pathogenic yeast C. glabrata. In addition, our data highlight that CgVac7, whose homologs are absent in higher eukaryotes, may represent a promising target for antifungal therapy.

scholarly journals Metabolic Reprogramming in the Opportunistic Yeast Candida albicans in Response to Hypoxia

mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Anaïs Burgain ◽  
Faiza Tebbji ◽  
Inès Khemiri ◽  
Adnane Sellam
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Metabolic Pathways ◽  
Membrane Lipids ◽  
Oxygen Depletion ◽  
Metabolic Reprogramming ◽  
Pathogenic Yeast ◽  
Fungal Virulence ◽  
Content Type ◽  
The Impact

ABSTRACT Hypoxia is the predominant condition that the human opportunistic fungus Candida albicans encounters in the majority of the colonized niches within the host. So far, the impact of such a condition on the overall metabolism of this important human-pathogenic yeast has not been investigated. Here, we have undertaken a time-resolved metabolomics analysis to uncover the metabolic landscape of fungal cells experiencing hypoxia. Our data showed a dynamic reprogramming of many fundamental metabolic pathways, such as glycolysis, the pentose phosphate pathway, and different metabolic routes related to fungal cell wall biogenesis. The C. albicans lipidome was highly affected by oxygen depletion, with an increased level of free fatty acids and biochemical intermediates of membrane lipids, including phospholipids, lysophospholipids, sphingolipids, and mevalonate. The depletion of oxygen-dependent lipids such as ergosterol or phosphatidylcholine with longer and polyunsaturated lateral fatty acid chains was observed only at the later hypoxic time point (180 min). Transcriptomics data supported the main metabolic response to hypoxia when matched to our metabolomic profiles. The hypoxic metabolome reflected different physiological alterations of the cell wall and plasma membrane of C. albicans under an oxygen-limiting environment that were confirmed by different approaches. This study provided a framework for future in vivo investigations to examine relevant hypoxic metabolic trajectories in fungal virulence and fitness within the host. IMPORTANCE A critical aspect of cell fitness is the ability to sense and adapt to variations in oxygen levels in their local environment. Candida albicans is an opportunistic yeast that is the most prevalent human fungal pathogen. While hypoxia is the predominant condition that C. albicans encounters in most of its niches, its impact on fungal metabolism remains unexplored so far. Here, we provided a detailed landscape of the C. albicans metabolome that emphasized the importance of many metabolic routes for the adaptation of this yeast to oxygen depletion. The fungal hypoxic metabolome identified in this work provides a framework for future investigations to assess the contribution of relevant metabolic pathways in the fitness of C. albicans and other human eukaryotic pathogens with similar colonized human niches. As hypoxia is present at most of the fungal infection foci in the host, hypoxic metabolic pathways are thus an attractive target for antifungal therapy.

scholarly journals Cell Wall Chitosan Is Necessary for Virulence in the Opportunistic Pathogen Cryptococcus neoformans

2011 ◽  
Vol 10 (9) ◽  
pp. 1264-1268 ◽  
Author(s):  
Lorina G. Baker ◽  
Charles A. Specht ◽  
Jennifer K. Lodge
Keyword(s):  
Cell Wall ◽  
Cryptococcus Neoformans ◽  
Fungal Pathogen ◽  
Slow Growth ◽  
Opportunistic Pathogen ◽  
Mammalian Host ◽  
Cell Integrity ◽  
Content Type ◽  
Opportunistic Fungal Pathogen ◽  
Chitin And Chitosan

ABSTRACTCryptococcus neoformansis an opportunistic fungal pathogen that causes meningoencephalitis. Its cell wall is composed of glucans, proteins, chitin, and chitosan. Multiple genetic approaches have defined a chitosan-deficient syndrome that includes slow growth and decreased cell integrity. Here we demonstrate chitosan is necessary for virulence and persistence in the mammalian host.

scholarly journals Multifactorial Role of Mitochondria in Echinocandin Tolerance Revealed by Transcriptome Analysis of Drug-Tolerant Cells

mBio ◽  
2021 ◽  
Author(s):  
Rocio Garcia-Rubio ◽  
Cristina Jimenez-Ortigosa ◽  
Lucius DeGregorio ◽  
Christopher Quinteros ◽  
Erika Shor ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Candida Glabrata ◽  
Clinical Failure ◽  
First Line ◽  
Content Type ◽  
First Line Therapy ◽  
Line Therapy ◽  
Resistant Strains ◽  
Opportunistic Fungal Pathogen

Echinocandin drugs are a first-line therapy to treat invasive candidiasis, which is a major source of morbidity and mortality worldwide. The opportunistic fungal pathogen Candida glabrata is a prominent bloodstream fungal pathogen, and it is notable for rapidly developing echinocandin-resistant strains associated with clinical failure.

scholarly journals Functional Characterization of Clinical Isolates of the Opportunistic Fungal Pathogen Aspergillus nidulans

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Rafael Wesley Bastos ◽  
Clara Valero ◽  
Lilian Pereira Silva ◽  
Taylor Schoen ◽  
Milton Drott ◽  
...  
Keyword(s):  
Cell Wall ◽  
Reference Strain ◽  
Carbon Sources ◽  
Neutrophil Function ◽  
Clinical Isolates ◽  
Biological Characterization ◽  
Content Type ◽  
Virulence Traits ◽  
Opportunistic Fungal Pathogen

ABSTRACT Aspergillus nidulans is an opportunistic fungal pathogen in patients with immunodeficiency, and virulence of A. nidulans isolates has mainly been studied in the context of chronic granulomatous disease (CGD), with characterization of clinical isolates obtained from non-CGD patients remaining elusive. This study therefore carried out a detailed biological characterization of two A. nidulans clinical isolates (CIs), obtained from a patient with breast carcinoma and pneumonia and from a patient with cystic fibrosis that underwent lung transplantation, and compared them to the reference, nonclinical FGSC A4 strain. Both CIs presented increased growth in comparison to that of the reference strain in the presence of physiologically relevant carbon sources. Metabolomic analyses showed that the three strains are metabolically very different from each other in these carbon sources. Furthermore, the CIs were highly susceptible to cell wall-perturbing agents but not to other physiologically relevant stresses. Genome analyses identified several frameshift variants in genes encoding cell wall integrity (CWI) signaling components. Significant differences in CWI signaling were confirmed by Western blotting among the three strains. In vivo virulence studies using several different models revealed that strain MO80069 had significantly higher virulence in hosts with impaired neutrophil function than the other strains. In summary, this study presents detailed biological characterization of two A. nidulans sensu stricto clinical isolates. Just as in Aspergillus fumigatus, strain heterogeneity exists in A. nidulans clinical strains that can define virulence traits. Further studies are required to fully characterize A. nidulans strain-specific virulence traits and pathogenicity. IMPORTANCE Immunocompromised patients are susceptible to infections with opportunistic filamentous fungi from the genus Aspergillus. Although A. fumigatus is the main etiological agent of Aspergillus species-related infections, other species, such as A. nidulans, are prevalent in a condition-specific manner. A. nidulans is a predominant infective agent in patients suffering from chronic granulomatous disease (CGD). A. nidulans isolates have mainly been studied in the context of CGD although infection with A. nidulans also occurs in non-CGD patients. This study carried out a detailed biological characterization of two non-CGD A. nidulans clinical isolates and compared the results to those with a reference strain. Phenotypic, metabolomic, and genomic analyses highlight fundamental differences in carbon source utilization, stress responses, and maintenance of cell wall integrity among the strains. One clinical strain had increased virulence in models with impaired neutrophil function. Just as in A. fumigatus, strain heterogeneity exists in A. nidulans clinical strains that can define virulence traits.

scholarly journals Candida glabrata Drug:H+Antiporter CgQdr2 Confers Imidazole Drug Resistance, Being Activated by Transcription Factor CgPdr1

2013 ◽  
Vol 57 (7) ◽  
pp. 3159-3167 ◽  
Author(s):  
Catarina Costa ◽  
Carla Pires ◽  
Tânia R. Cabrito ◽  
Adeline Renaudin ◽  
Michiyo Ohno ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Transcription Factor ◽  
Multidrug Resistance ◽  
Candida Glabrata ◽  
Antifungal Drugs ◽  
Antifungal Drug ◽  
Major Facilitator Superfamily ◽  
Pathogenic Yeast ◽  
Content Type ◽  
Antifungal Drug Resistance

ABSTRACTThe widespread emergence of antifungal drug resistance poses a severe clinical problem. Though predicted to play a role in this phenomenon, the drug:H+antiporters (DHA) of the major facilitator superfamily have largely escaped characterization in pathogenic yeasts. This work describes the first DHA from the pathogenic yeastCandida glabratareported to be involved in antifungal drug resistance, theC. glabrata QDR2(CgQDR2) gene (ORFCAGL0G08624g). The expression ofCgQDR2inC. glabratawas found to confer resistance to the antifungal drugs miconazole, tioconazole, clotrimazole, and ketoconazole. By use of a green fluorescent protein (GFP) fusion, the CgQdr2 protein was found to be targeted to the plasma membrane inC. glabrata. In agreement with these observations,CgQDR2expression was found to decrease the intracellular accumulation of radiolabeled clotrimazole inC. glabrataand to play a role in the extrusion of this antifungal from preloaded cells. Interestingly, the functional heterologous expression ofCgQDR2in the model yeastSaccharomyces cerevisiaefurther confirmed the role of this gene as a multidrug resistance determinant: its expression was able to complement the susceptibility phenotype exhibited by itsS. cerevisiaehomologue,QDR2, in the presence of imidazoles and of the antimalarial and antiarrhythmic drug quinidine. In contrast to the findings reported for Qdr2, CgQdr2 expression does not contribute to the ability of yeast to grow under K+-limiting conditions. Interestingly,CgQDR2transcript levels were seen to be upregulated inC. glabratacells challenged with clotrimazole or quinidine. This upregulation was found to depend directly on the transcription factor CgPdr1, the major regulator of multidrug resistance in this pathogenic yeast, which has also been found to be a determinant of quinidine and clotrimazole resistance inC. glabrata.

scholarly journals Pneumocystis carinii Interactions with Lung Epithelial Cells and Matrix Proteins Induce Expression and Activity of the PcSte20 Kinase with Subsequent Phosphorylation of the Downstream Cell Wall Biosynthesis Kinase PcCbk1

2011 ◽  
Vol 79 (10) ◽  
pp. 4157-4164 ◽  
Author(s):  
Theodore J. Kottom ◽  
Joshua W. Burgess ◽  
Andrew H. Limper
Keyword(s):  
Cell Wall ◽  
Epithelial Cells ◽  
Fungal Pathogen ◽  
Pneumocystis Carinii ◽  
Specific Region ◽  
Lung Epithelial Cells ◽  
Matrix Proteins ◽  
Content Type ◽  
Lung Epithelial ◽  
Opportunistic Fungal Pathogen

ABSTRACTEukaryotic cell proliferation and phenotype are highly regulated by contact-dependent mechanisms. We have previously shown that the binding and interaction of the opportunistic fungal pathogenPneumocystis cariniito lung epithelial cells and extracellular matrix proteins induces mRNA expression of both the mitogen-activated protein (MAP) kinaseP. cariniiSte20 (PcSte20) and the cell wall-remodeling enzymePcCbk1(16). Herein, we report that in addition toPcSte20mRNA expression being upregulated,PneumocystisPcSte20 kinase activity is increased upon interacting with these same lung targets. This activity is also significantly suppressed byClostridium difficiletoxin B, a pan-specific inhibitor of small GTPases, demonstrating the potential role of a Cdc42-like molecule in this signaling cascade. We further observed that the PcSte20 kinase physically interacts with a specific region of theP. cariniicell wall biosynthesis kinase, PcCbk1, a downstream kinase important for mating projection formation and cell wall remodeling. This direct binding was mapped to a specific region of the PcCbk1 protein. We also demonstrated that PcSte20 obtained from wholeP. cariniilysates has the ability to phosphorylate PcCbk1 after the organism interacts with lung epithelial cells and extracellular matrix components. These observations provide new insights intoP. cariniisignaling induced by interactions of this important opportunistic fungal pathogen with lung epithelial cells and matrix.

scholarly journals Evidence that Ergosterol Biosynthesis Modulates Activity of the Pdr1 Transcription Factor inCandida glabrata

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Bao Gia Vu ◽  
Grace Heredge Thomas ◽  
W. Scott Moye-Rowley
Keyword(s):  
Transcription Factor ◽  
Candida Glabrata ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Atp Binding ◽  
Pathogenic Yeast ◽  
Content Type ◽  
Atp Binding Cassette Transporter ◽  
Encoding Gene ◽  
Atp Binding Cassette

ABSTRACTA crucial limitation in antifungal chemotherapy is the limited number of antifungal drugs currently available. Azole drugs represent the most commonly used chemotherapeutic, and loss of efficacy of these drugs is a major risk factor in successful treatment of a variety of fungal diseases.Candida glabratais a pathogenic yeast that is increasingly found associated with bloodstream infections, a finding likely contributed to by its proclivity to develop azole drug resistance.C. glabrataoften acquires azole resistance via gain-of-function (GOF) mutations in the transcription factor Pdr1. These GOF forms of Pdr1 drive elevated expression of target genes, including the ATP-binding cassette transporter-encodingCDR1locus. GOF alleles ofPDR1have been extensively studied, but little is known of how Pdr1 is normally regulated. Here we test the idea that reduction of ergosterol biosynthesis (as occurs in the presence of azole drugs) might trigger activation of Pdr1 function. Using two different means of genetically inhibiting ergosterol biosynthesis, we demonstrated that Pdr1 activity and target gene expression are elevated in the absence of azole drug. Blocks at different points in the ergosterol pathway lead to Pdr1 activation as well as to induction of other genes in this pathway. Delivery of the signal from the ergosterol pathway to Pdr1 involves the transcription factor Upc2A, anERGgene regulator. We show that Upc2A binds directly to thePDR1andCDR1promoters. Our studies argue for a physiological link between ergosterol biosynthesis and Pdr1-dependent gene regulation that is not restricted to efflux of azole drugs.IMPORTANCEA likely contributor to the increased incidence of non-albicanscandidemias involvingCandida glabratais the ease with which this yeast acquires azole resistance, in large part due to induction of the ATP-binding cassette transporter-encoding geneCDR1. Azole drugs lead to induction of Pdr1 transactivation, with a central model being that this factor binds these drugs directly. Here we provide evidence that Pdr1 is activated without azole drugs by the use of genetic means to inhibit expression of azole drug target-encoding geneERG11. These acute reductions in Erg11 levels lead to elevated Pdr1 activity even though no drug is present. A key transcriptional regulator of theERGpathway, Upc2A, is shown to directly bind to thePDR1andCDR1promoters. We interpret these data as support for the view that Pdr1 function is responsive to ergosterol biosynthesis and suggest that this connection reveals the normal physiological circuitry in which Pdr1 participates.

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

2021 ◽  
Author(s):  
Ana Gaspar-Cordeiro ◽  
Catarina Amaral ◽  
Vania Pobre ◽  
Wilson Antunes ◽  
Ana Petronilho ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Candida Glabrata ◽  
Zinc Homeostasis ◽  
Ergosterol Biosynthesis ◽  
Gene Encoding ◽  
Pathogenic Yeast ◽  
Transcription Regulator ◽  
Opportunistic Pathogenic ◽  
Irregular Cell

The synergistic combinations of drugs are promising strategies to boost the effectiveness of current antifungals and thus prevent the emergence of resistance. In this work, we show that copper and the antifungal fluconazole act synergistically against Candida glabrata, an opportunistic pathogenic yeast intrinsically tolerant to fluconazole. Analyses of the transcriptomic profile of C. glabrata after the combination of copper and fluconazole showed that the expression of the multidrug transporter gene CDR1 was decreased, suggesting that fluconazole efflux could be affected. In agreement, we observed that copper inhibits the transactivation of Pdr1, the transcription regulator of multidrug transporters, and leads to the intracellular accumulation of fluconazole. Copper also decreases the transcriptional induction of ergosterol biosynthesis (ERG) genes by fluconazole, which culminates in the accumulation of toxic sterols. Co-treatment of cells with copper and fluconazole should affect the function of proteins located in the plasma membrane, as several ultrastructural alterations, including irregular cell wall and plasma membrane and loss of cell wall integrity, were observed. Finally, we show that the combination of copper and fluconazole downregulates the expression of the gene encoding the zinc-responsive transcription regulator Zap1, which possibly, together with the membrane transporters malfunction, generates zinc depletion. Supplementation with zinc reverts the toxic effect of combining copper with fluconazole, underscoring the importance of this metal in the observed synergistic effect. Overall, this work, while unveiling the molecular basis that supports the use of copper to enhance the effectiveness of fluconazole, paves the way for the development of new metal-based antifungal strategies.

scholarly journals Candida albicans ENT2 Contributes to Efficient Endocytosis, Cell Wall Integrity, Filamentation, and Virulence

mSphere ◽  
2021 ◽  
Author(s):  
Christiane Rollenhagen ◽  
Harrison Agyeman ◽  
Susan Eszterhas ◽  
Samuel A. Lee
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Fungal Pathogen ◽  
Clinical Importance ◽  
Hospitalized Patients ◽  
Cell Wall Integrity ◽  
Content Type ◽  
Invasive Infections ◽  
Opportunistic Fungal Pathogen ◽  
Considerable Morbidity

The opportunistic fungal pathogen Candida albicans is an important cause of invasive infections in hospitalized patients and a source of considerable morbidity and mortality. Despite its clinical importance, we still need to improve our ability to diagnose and treat this common pathogen.

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