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. 2018 Aug 8;13(8):e0201969.
doi: 10.1371/journal.pone.0201969. eCollection 2018.

Cranberry-derived Proanthocyanidins Induce a Differential Transcriptomic Response Within Candida Albicans Urinary Biofilms

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Free PMC article

Cranberry-derived Proanthocyanidins Induce a Differential Transcriptomic Response Within Candida Albicans Urinary Biofilms

Anitha Sundararajan et al. PLoS One. .
Free PMC article

Abstract

Candida albicans is one of the most common causes of hospital-acquired urinary tract infections (UTIs). However, azoles are poorly active against biofilms, echinocandins do not achieve clinically useful urinary concentrations, and amphotericin B exhibits severe toxicities. Thus, novel strategies are needed to prevent Candida UTIs, which are often associated with urinary catheter biofilms. We previously demonstrated that cranberry-derived proanthocyanidins (PACs) prevent C. albicans biofilm formation in an in vitro urinary model. To elucidate functional pathways unique to urinary biofilm development and PAC inhibition, we investigated the transcriptome of C. albicans in artificial urine (AU), with and without PACs. C. albicans biofilm and planktonic cells were cultivated with or without PACs. Genome-wide expression analysis was performed by RNA sequencing. Differentially expressed genes were determined using DESeq2 software; pathway analysis was performed using Cytoscape. Approximately 2,341 of 6,444 total genes were significantly expressed in biofilm relative to planktonic cells. Functional pathway analysis revealed that genes involved in filamentation, adhesion, drug response and transport were up-regulated in urinary biofilms. Genes involved in carbon and nitrogen metabolism and nutrient response were down-regulated. In PAC-treated urinary biofilms compared to untreated control biofilms, 557 of 6,444 genes had significant changes in gene expression. Genes downregulated in PAC-treated biofilms were implicated in iron starvation and adhesion pathways. Although urinary biofilms share key features with biofilms formed in other environments, many genes are uniquely expressed in urinary biofilms. Cranberry-derived PACs interfere with the expression of iron acquisition and adhesion genes within urinary biofilms.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Dendrogram representing hierarchical sample clustering representing high correlation between the samples.
Sample clustering was performed as part of the DESeq tool. The dist function was applied to the transpose of transformed count matrix to obtain sample-to-sample distances. A heat map of this distance matrix highlights the differences and similarities between samples.
Fig 2
Fig 2. Venn diagram analysis of gene expression.
Genes differentially expressed between the three conditions, namely, untreated biofilms, PAC-treated biofilms and PAC-treated planktonic cells were determined as compared to planktonic cells in AU. A) Venn diagram illustrating the number of upregulated genes within each comparison and shared genes between different conditions. B) Venn diagram illustrating the number of downregulated genes within each comparison and shared genes between different conditions.
Fig 3
Fig 3. Heatmap of the top differentially-expressed genes across all treatments.
The top differentially-expressed genes across all treatments as compared to planktonic cells in AU were selected using DESeq2 with the DEApp tool, with an increased cut-off defined as a p-adjusted value of less than or equal to 0.01 and a fold-change of 5 or higher. The top differentially-expressed genes were visualized using the Heatmapper web tool [42]. Red coloring indicates down-regulation as compared to planktonic cells in AU; black indicates no change in expression compared to planktonic cells in AU; green indicates up-regulation as compared to planktonic cells in AU. Dendrogram indicates hierarchical clustering between samples (top) or genes (right).
Fig 4
Fig 4. Pathway analysis of differentially-expressed genes as determined by RNA Seq in urinary biofilms.
Analysis was completed using the ClueGO plugin for Cytoscape and the Candida Genome Database GOSlim annotation. (A) Pathway analysis of differentially-expressed genes in urinary biofilms compared to planktonic cells in AU. Genes involved in adhesion, filamentation biofilm formation, transport, lipid metabolism and response to stress were up-regulated in urinary biofilms. (B) Genes involved in carbohydrate metabolism, cellular homeostasis, oxidoreductase activity, and lyase activity were down-regulated in urinary biofilms.
Fig 5
Fig 5. Differentially-expressed biofilm-related genes.
Genes previously shown to have roles in biofilm formation were broken into different functional categories as in Finkel and Mitchell [53]. Genes up- or down-regulated in biofilms as compared to planktonic cells or in PAC-treated biofilms as compared to biofilms alone are indicated by arrows. Negative regulators of biofilm formation are indicated by asterisks (*). Genes indicated in bold are those with potentially unexpected expression changes compared to biofilms formed in serum-like conditions.
Fig 6
Fig 6. Pathway analysis of differentially-expressed genes as determined by RNA Seq in PAC-treated biofilms.
Analysis was completed using the ClueGO plugin for Cytoscape and the Candida Genome Database GOSlim annotation. (A) Genes that are up-expressed in PAC-treated biofilms were enriched for oxidoreductase-activity related genes. (B) Genes that are down-expressed in PAC treated biofilms and the genes mainly fall under processes such as regulation of filamentous growth, adhesion and biofilm formation.

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References

    1. Gardner A, Mitchell B, Beckingham W, Fasugba O. A point prevalence cross-sectional study of healthcare-associated urinary tract infections in six Australian hospitals. BMJ Open. 2014;4: e005099–e005099. 10.1136/bmjopen-2014-005099 - DOI - PMC - PubMed
    1. Tambyah PA, Knasinski V, Maki DG. The direct costs of nosocomial catheter-associated urinary tract infection in the era of managed care. Infect Control Hosp Epidemiol. 2002;23: 27–31. 10.1086/501964 - DOI - PubMed
    1. Bouza E, San Juan R, Muñoz P, Voss A, Kluytmans J, Co-operative Group of the European Study Group on Nosocomial Infections. A European perspective on nosocomial urinary tract infections II. Report on incidence, clinical characteristics and outcome (ESGNI-004 study). Clin Microbiol Infect. 2001;7: 532–542. - PubMed
    1. Kauffman CA, Vazquez JA, Sobel JD, Gallis HA, McKinsey DS, Karchmer AW, et al. Prospective multicenter surveillance study of funguria in hospitalized patients. The National Institute for Allergy and Infectious Diseases (NIAID) Mycoses Study Group. Clin Infect Dis. 2000;30: 14–18. 10.1086/313583 - DOI - PubMed
    1. Achkar JM, Fries BC. Candida infections of the genitourinary tract. Clin Microbiol Rev. 2010;23: 253–273. 10.1128/CMR.00076-09 - DOI - PMC - PubMed

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