scholarly journals Selection of Candida albicans Trisomy during Oropharyngeal Infection Results in a Commensal-Like Phenotype

2019 ◽  
Author(s):  
Anja Forche ◽  
Norma V. Solis ◽  
Marc Swidergall ◽  
Robert Thomas ◽  
Alison Guyer ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Post Infection ◽  
Large Scale ◽  
De Novo ◽  
Point Mutations ◽  
Oral Epithelial Cells ◽  
Oropharyngeal Infection ◽  
Oropharyngeal Cavity ◽  
Oral Epithelial

AbstractWhen the fungus Candida albicans proliferates in the oropharyngeal cavity during experimental oropharyngeal candidiasis (OPC), it undergoes large-scale genome changes at a much higher frequency than when it grows in vitro. Previously, we identified a specific whole chromosome amplification, trisomy of Chr 6 (Chr6x3), that was highly overrepresented among strains recovered from the tongues of mice with OPC. To determine the functional significance of this trisomy, we assessed the virulence of two Chr6 trisomic strains and a Chr5 trisomic strain in the mouse model of OPC. We also analyzed the expression of virulence-associated traits in vitro. All three trisomic strains exhibited characteristics of a commensal during OPC in mice. They achieved the same oral fungal burden as the diploid progenitor strain but caused significantly less weight loss and elicited a significantly lower inflammatory host response. In vitro, all three trisomic strains had reduced capacity to adhere to and invade oral epithelial cells and increased susceptibility to neutrophil killing. Whole genome sequencing of pre- and post-infection isolates found that the trisomies were usually maintained. Most post-infection isolates also contained de novo point mutations, but these were not conserved. While in vitro growth assays did not reveal phenotypes specific to de novo point mutations, they did reveal novel phenotypes specific to each lineage. These data reveal that during OPC, clones that are trisomic for Chr5 or Chr6 are selected and they facilitate a commensal-like phenotype.

scholarly journals Novel Aggregation Properties of Candida albicans Secreted Aspartyl Proteinase Sap6 Mediate Virulence in Oral Candidiasis

2015 ◽  
Vol 83 (7) ◽  
pp. 2614-2626 ◽  
Author(s):  
Rohitashw Kumar ◽  
Darpan Saraswat ◽  
Swetha Tati ◽  
Mira Edgerton
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Oral Candidiasis ◽  
Oral Microbiome ◽  
Proteinase Activity ◽  
Adhesion Properties ◽  
Content Type ◽  
Oral Epithelial Cells ◽  
Oral Epithelial ◽  
Cell Cell

Candida albicans, a commensal fungus of the oral microbiome, causes oral candidiasis in humans with localized or systemic immune deficiencies. Secreted aspartic proteinases (Saps) are a family of 10 related proteases and are virulence factors due to their proteolytic activity, as well as their roles in adherence and colonization of host tissues. We found that mice infected sublingually withC. albicanscells overexpressing Sap6 (SAP6OE and a Δsap8strain) had thicker fungal plaques and more severe oral infection, while infection with the Δsap6strain was attenuated. These hypervirulent strains had highly aggregative colony structurein vitroand higher secreted proteinase activity; however, the levels of proteinase activity ofC. albicansSaps did not uniformly match their abilities to damage cultured oral epithelial cells (SCC-15 cells). Hyphal induction in cells overexpressing Sap6 (SAP6OE and Δsap8cells) resulted in formation of large cell-cell aggregates. These aggregates could be produced in germinated wild-type cells by addition of native or heat-inactivated Sap6. Sap6 bound only to germinated cells and increasedC. albicansadhesion to oral epithelial cells. The adhesion properties of Sap6 were lost upon deletion of its integrin-binding motif (RGD) and could be inhibited by addition of RGD peptide or anti-integrin antibodies. Thus, Sap6 (but not Sap5) has an alternative novel function in cell-cell aggregation, independent of its proteinase activity, to promote infection and virulence in oral candidiasis.

scholarly journals Activation of EphA2-EGFR signaling in oral epithelial cells by Candida albicans virulence factors

2021 ◽  
Vol 17 (1) ◽  
pp. e1009221
Author(s):  
Marc Swidergall ◽  
Norma V. Solis ◽  
Nicolas Millet ◽  
Manning Y. Huang ◽  
Jianfeng Lin ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Virulence Factors ◽  
Growth Factor Receptor ◽  
Egfr Signaling ◽  
High Concentration ◽  
Oral Epithelial Cells ◽  
Proinflammatory Mediators ◽  
Epidermal Growth ◽  
Oral Epithelial

During oropharyngeal candidiasis (OPC), Candida albicans invades and damages oral epithelial cells, which respond by producing proinflammatory mediators that recruit phagocytes to foci of infection. The ephrin type-A receptor 2 (EphA2) detects β-glucan and plays a central role in stimulating epithelial cells to release proinflammatory mediators during OPC. The epidermal growth factor receptor (EGFR) also interacts with C. albicans and is known to be activated by the Als3 adhesin/invasin and the candidalysin pore-forming toxin. Here, we investigated the interactions among EphA2, EGFR, Als3 and candidalysin during OPC. We found that EGFR and EphA2 constitutively associate with each other as part of a heteromeric physical complex and are mutually dependent for C. albicans-induced activation. Als3-mediated endocytosis of a C. albicans hypha leads to the formation of an endocytic vacuole where candidalysin accumulates at high concentration. Thus, Als3 potentiates targeting of candidalysin, and both Als3 and candidalysin are required for C. albicans to cause maximal damage to oral epithelial cells, sustain activation of EphA2 and EGFR, and stimulate pro-inflammatory cytokine and chemokine secretion. In the mouse model of OPC, C. albicans-induced production of CXCL1/KC and CCL20 is dependent on the presence of candidalysin and EGFR, but independent of Als3. The production of IL-1α and IL-17A also requires candidalysin but is independent of Als3 and EGFR. The production of TNFα requires Als1, Als3, and candidalysin. Collectively, these results delineate the complex interplay among host cell receptors EphA2 and EGFR and C. albicans virulence factors Als1, Als3 and candidalysin during the induction of OPC and the resulting oral inflammatory response.

Molecular genetic analysis of Saccharomyces cerevisiae C1-tetrahydrofolate synthase mutants reveals a noncatalytic function of the ADE3 gene product and an additional folate-dependent enzyme

1990 ◽  
Vol 10 (11) ◽  
pp. 5679-5687
Author(s):  
C K Barlowe ◽  
D R Appling
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Point Mutations ◽  
Gene Replacement ◽  
Molecular Genetic Analysis ◽  
Yeast Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Purine Synthesis

In eucaryotes, 10-formyltetrahydrofolate (formyl-THF) synthetase, 5,10-methenyl-THF cyclohydrolase, and NADP(+)-dependent 5,10-methylene-THF dehydrogenase activities are present on a single polypeptide termed C1-THF synthase. This trifunctional enzyme, encoded by the ADE3 gene in the yeast Saccharomyces cerevisiae, is thought to be responsible for the synthesis of the one-carbon donor 10-formyl-THF for de novo purine synthesis. Deletion of the ADE3 gene causes adenine auxotrophy, presumably as a result of the lack of cytoplasmic 10-formyl-THF. In this report, defined point mutations that affected one or more of the catalytic activities of yeast C1-THF synthase were generated in vitro and transferred to the chromosomal ADE3 locus by gene replacement. In contrast to ADE3 deletions, point mutations that inactivated all three activities of C1-THF synthase did not result in an adenine requirement. Heterologous expression of the Clostridium acidiurici gene encoding a monofunctional 10-formyl-THF synthetase in an ade3 deletion strain did not restore growth in the absence of adenine, even though the monofunctional synthetase was catalytically competent in vivo. These results indicate that adequate cytoplasmic 10-formyl-THF can be produced by an enzyme(s) other than C1-THF synthase, but efficient utilization of that 10-formyl-THF for purine synthesis requires a nonenzymatic function of C1-THF synthase. A monofunctional 5,10-methylene-THF dehydrogenase, dependent on NAD+ for catalysis, has been identified and purified from yeast cells (C. K. Barlowe and D. R. Appling, Biochemistry 29:7089-7094, 1990). We propose that the characteristics of strains expressing full-length but catalytically inactive C1-THF synthase could result from the formation of a purine-synthesizing multienzyme complex involving the structurally unchanged C1-THF synthase and that production of the necessary one-carbon units in these strains is accomplished by an NAD+ -dependent 5,10-methylene-THF dehydrogenase.

scholarly journals Determination of the effects of cinnamon bark fractions on Candida albicans and oral epithelial cells

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Marie-Pier Veilleux ◽  
Daniel Grenier
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Essential Oil ◽  
Biofilm Formation ◽  
Epithelial Barrier ◽  
Cinnamon Oil ◽  
Cinnamon Bark ◽  
Oral Epithelial Cells ◽  
Oral Epithelial

Abstract Background Candida albicans is an opportunistic pathogen that causes oral candidiasis and denture stomatitis. It has also been reported to infect oral mucositis lesions in patients who suffer from cancer affecting the head and neck and who receive chemotherapy and radiotherapy treatments. This study aimed to investigate the effects of two cinnamon bark fractions, i.e., an essential oil and an aqueous extract enriched in proanthocyanidins (Cinnulin PF®) on growth, biofilm formation, and adherence properties of C. albicans as well as on oral epithelial cells (barrier integrity, inflammatory response). Methods A microplate dilution assay was used to determine antifungal and anti-biofilm properties. A fluorescent assay was used to determine C. albicans adherence to oral epithelial cells. Cytotoxicity toward oral epithelial cells was assessed by determination of cell metabolic activity. Tight junction integrity of gingival keratinocytes was assessed by determination of transepithelial electrical resistance. IL-6 and IL-8 secretion by TNFα-stimulated oral epithelial cells was quantified by ELISA. Results While Cinnulin PF® did not reduce C. albicans growth, the cinnamon bark oil exhibited high antifungal activity with minimum inhibitory concentrations and minimum fungicidal concentrations in the range of 0.039 to 0.078%. The cinnamon oil was also active against a pre-formed C. albicans biofilm. Interestingly, Cinnulin PF® prevented biofilm formation by C. albicans and attenuated its adherence to oral epithelial cells. At their effective concentrations, the cinnamon oil and the Cinnulin PF® displayed no significant cytotoxicity against oral epithelial cells. In an in vitro model, both cinnamon fractions reinforced the integrity of the oral epithelial barrier. Lastly, Cinnulin PF® inhibited the secretion of interleukin-6 and interleukin-8 by oral epithelial cells stimulated with TNF-α. Conclusion By their ability to attenuate growth, biofilm formation and adherence property of C. albicans, to reinforce the epithelial barrier function, and to exert anti-inflammatory properties the two cinnamon fractions (essential oil, Cinnulin PF®) investigated in the present study may be promising agents for treating oral infections involving C. albicans.

scholarly journals From Attachment to Damage: Defined Genes of Candida albicans Mediate Adhesion, Invasion and Damage during Interaction with Oral Epithelial Cells

PLoS ONE ◽  
2011 ◽  
Vol 6 (2) ◽  
pp. e17046 ◽  
Author(s):  
Betty Wächtler ◽  
Duncan Wilson ◽  
Katja Haedicke ◽  
Frederic Dalle ◽  
Bernhard Hube
Keyword(s):  
Candida Albicans ◽  
Epithelial Cells ◽  
Oral Epithelial Cells ◽  
Oral Epithelial

scholarly journals In Vitro Studies on Erythrosine-Based Photodynamic Therapy of Malignant and Pre-Malignant Oral Epithelial Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e34475 ◽  
Author(s):  
Abhishek D. Garg ◽  
Muthiah Bose ◽  
Mohammed I. Ahmed ◽  
William A. Bonass ◽  
Simon R. Wood
Keyword(s):  
Photodynamic Therapy ◽  
Epithelial Cells ◽  
In Vitro Studies ◽  
Oral Epithelial Cells ◽  
Oral Epithelial

scholarly journals The Influence of Oral Bacteria on Epithelial Cell MigrationIn Vitro

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Alexa M. G. A. Laheij ◽  
Johannes J. de Soet ◽  
Enno C. I. Veerman ◽  
Jan G. M. Bolscher ◽  
Cor van Loveren
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Oral Bacteria ◽  
Bacterial Cells ◽  
Oral Epithelial Cells ◽  
Prevotella Nigrescens ◽  
Hematopoetic Stem Cell ◽  
Oral Epithelial ◽  
Hematopoetic Stem Cell Transplantation

Oral ulcerations often arise as a side effect from chemo- and radiation therapy. In a previous clinical study,Porphyromonas gingivaliswas identified as a positive predictor for oral ulcerations after hematopoetic stem cell transplantation, possibly incriminatingP. gingivalisin delayed healing of the ulcerations. Therefore, it was tested whetherP. gingivalisand its secreted products could inhibit the migration of oral epithelial cells in anin vitroscratch assay. To compare, the oral bacteriaPrevotella nigrescens,Prevotella intermedia,Tannerella forsythia, andStreptococcus mitiswere included. A standardized scratch was made in a confluent layer of human oral epithelial cells. The epithelial cells were challenged with bacterial cells and with medium containing secretions of these bacteria. Closure of the scratch was measured after 17 h using a phase contrast microscope.P. gingivalis,P. nigrescens, and secretions ofP. gingivalisstrongly inhibited cell migration. A challenge with 1000 heat-killed bacteria versus 1 epithelial cell resulted in a relative closure of the scratch of 25% forP. gingivalisand 20% forP. nigrescens. Weaker inhibitory effects were found for the other bacteria. The results confirmed our hypothesis that the oral bacteria may be involved in delayed wound healing.

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