A multifunctional, synthetic Gaussia princeps luciferase reporter for live imaging of Candida albicans infections

Peer reviewedPublisher PD

Beneficial effect of Mentha suaveolens essential oil in the treatment of vaginal candidiasis assessed by real-time monitoring of infection

<p>Abstract</p> <p>Background</p> <p>Vaginal candidiasis is a frequent and common distressing disease affecting up to 75% of the women of fertile age; most of these women have recurrent episodes. Essential oils from aromatic plants have been shown to have antimicrobial and antifungal activities. This study was aimed at assessing the anti-fungal activity of essential oil from <it>Mentha suaveolens </it>(EOMS) in an experimental infection of vaginal candidiasis.</p> <p>Methods</p> <p>The <it>in vitro </it>and <it>in vivo </it>activity of EOMS was assessed. The <it>in vitro </it>activity was evaluated under standard CLSI methods, and the <it>in vivo </it>analysis was carried out by exploiting a novel, non-invasive model of vaginal candidiasis in mice based on an <it>in vivo </it>imaging technique.</p> <p>Differences between essential oil treated and saline treated mice were evaluated by the non-parametric Mann-Whitney U-test. Viable count data from a time kill assay and yeast and hyphae survival test were compared using the Student's t-test (two-tailed).</p> <p>Results</p> <p>Our main findings were: i) EOMS shows potent candidastatic and candidacidal activity in an <it>in vitro </it>experimental system; ii) EOMS gives a degree of protection against vaginal candidiasis in an <it>in vivo </it>experimental system.</p> <p>Conclusions</p> <p>This study shows for the first time that the essential oil of a Moroccan plant <it>Mentha suaveolens </it>is candidastatic and candidacidal <it>in vitro</it>, and has a degree of anticandidal activity in a model of vaginal infection, as demonstrated in an <it>in vivo </it>monitoring imaging system. We conclude that our findings lay the ground for further, more extensive investigations to identify the active EOMS component(s), promising in the therapeutically problematic setting of chronic vaginal candidiasis in humans.</p

Th17 Cells and IL-17 in Protective Immunity to Vaginal Candidiasis

Background: Th17 cells play a major role in coordinating the host defence in oropharyngeal candidiasis. In this study we investigated the involvement of the Th17 response in an animal model of vulvovaginal candidiasis (VVC). Methods: To monitor the course of infection we exploited a new in vivo imaging technique. Results: i) The progression of VVC leads to a strong influx of neutrophils in the vagina soon after the challenge which persisted despite the resolution of infection; ii) IL-17, produced by vaginal cells, particularly CD4 T cells, was detected in the vaginal wash during the infection, reaching a maximum 14 days after the challenge; iii) The amount and kinetics of IL-23 in vaginal fluids were comparable to those in vaginal cells; iv) The inhibition of Th17 differentiation led to significant inhibition of IL-17 production with consequent exacerbation of infection; v) An increased production of bdefensin 2 was manifested in cells of infected mice. This production was strongly reduced when Th17 differentiation was inhibited and was increased by rIL-17 treatment. Conclusions: These results imply that IL-17 and Th17, along with innate antimicrobial factors, have a role in the immune response to vaginal candidiasis

A Luciferase Reporter for Gene Expression Studies and Dynamic Imaging of Superficial Candida albicans Infections

International audienceReal-time imaging of fungal infections is becoming integral to the study of host-pathogen interactions, as it allows monitoring of the spatial and temporal progression of pathogen growth or of the host response in a single animal as well as reducing the number of animals used to obtain signifi cant data. We present different applications of a novel luciferase reporter gene constructed from the coding sequences of the Candida albicans PGA59 gene, encoding a GPI-linked cell wall protein, and the Gaussia princeps luciferase gene. Upon addition of the coelenterazine substrate, light produced by the surface-exposed luciferase can be used to quantify gene expression from a variety of C. albicans promoters as well as monitoring cutaneous, subcutaneous, and vaginal infections

The Inflammatory Response Induced by Aspartic Proteases of Candida albicans Is Independent of Proteolytic Activity ▿

The secretion of aspartic proteases (Saps) has long been recognized as a virulence-associated trait of the pathogenic yeast Candida albicans. In this study, we report that different recombinant Saps, including Sap1, Sap2, Sap3, and Sap6, have differing abilities to induce secretion of proinflammatory cytokines by human monocytes. In particular Sap1, Sap2, and Sap6 significantly induced interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), and IL-6 production. Sap3 was able to stimulate the secretion of IL-1β and TNF-α. All Saps tested were able to induce Ca2+ influx in monocytes. Treatment of these Saps with pepstatin A did not have any effect on cytokine secretion, indicating that their stimulatory potential was independent from their proteolytic activity. The capacity of Saps to induce inflammatory cytokine production was also independent from protease-activated receptor (PAR) activation and from the optimal pH for individual Sap activity. The interaction of Saps with monocytes induced Akt activation and phosphorylation of IκBα, which mediates translocation of NF-κB into the nucleus. Overall, these results suggest that individual Sap proteins can induce an inflammatory response and that this phenomenon is independent from the pH of a specific host niche and from Sap enzymatic activity. The inflammatory response is partially dependent on Sap denaturation and is triggered by the Akt/NF-κB activation pathway. Our data suggest a novel, activity-independent aspect of Saps during interactions of C. albicans with the host

An Anti-β-Glucan Monoclonal Antibody Inhibits Growth and Capsule Formation of Cryptococcus neoformans In Vitro and Exerts Therapeutic, Anticryptococcal Activity In Vivo▿

In this study we tested the in vitro and in vivo anti-Cryptococcus neoformans activity of an antilaminarin (anti-β-glucan) monoclonal antibody (MAb 2G8) (immunoglobulin G2b) which was previously shown to inhibit the growth of β-glucan-exposing Candida albicans cells. Here we show that MAb 2G8 binds to the cell wall of C. neoformans and inhibits its growth to an extent comparable to that observed for C. albicans. Binding and growth inhibition were detected almost equally for encapsulated and acapsular C. neoformans strains. In addition, at subinhibitory concentrations, MAb 2G8 reduced the capsule thickness without affecting protease or phospholipase production. Acapsular fungal cells, but not encapsulated fungal cells, were opsonized by the antibody and more efficiently phagocytosed and killed by human monocytes and by murine peritoneal macrophages. A single administration of MAb 2G8 resulted in a reduction in the fungal burden in the brains and livers of mice systemically infected with a highly virulent, encapsulated C. neoformans strain. This protective effect was also detected in neutropenic mice. Overall, these findings demonstrate that cell wall β-glucan of encapsulated C. neoformans is accessible to antibodies which can exert remarkable anticryptococcal activities in vitro and in vivo

Effect of halofuginone on vaginal infection.

<p>Mice, under pseudo-estrus conditions, were twice infected with 10⁷<i>Candida albicans</i> in vagina. Two days before and every two days after infection, mice were injected intraperitoneally with 5 µg/100 µl or 10 µg/100 µl of halofuginone solution or diluent of halofuginone and, in selected experiments, were treated intravaginally with 10 pg of mouse rIL-17. (A) Evaluation of IL-17 concentration by ELISA in supernatants of vaginal fluids obtained at different days after vaginal <i>Candida</i> infection and halofuginone treatment. Results are expressed as mean±SD (n = 9 mice, 3 mice for each of three separate experiments). The statistical analysis was performed using Mann-Whitney U test. * <i>p</i><0.05, ** <i>p</i><0.01 (infected halofuginone treated mice vs infected diluent treated mice). At day 4, 14 and 25 after infection, mice were treated intravaginally with 10 µg of coelenterazine and imaged in the IVIS-200™ imaging system under anesthesia using 2.5% isoflurane and the vaginal lumen was washed with 150 µl of saline. (B) In vivo imaging of mice vaginally infected with <i>Candida albicans</i> cells (gLUC) and treated with halofuginone or diluent. Images are representative of 5 out of 10 mice in two different experiments. (C) Dot plot of total photon emission from the infected regions and dot plot of CFU in vaginal washes of mice (n = 10) treated with halofuginone or diluent. The statistical analysis was performed using non-parametric Mann-Whitney U test. The median is indicated by a straight line. Data are representative of one out of two independent experiments with similar results. * <i>p</i><0.05, ** <i>p</i><0.01 (infected halofuginone treated mice vs infected diluent treated mice).</p