Browsing by Subject "Candida albicans"
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- PublicationOpen AccessAnalysis of validamycin as a potential antifungal compound against Candida albicans(Institut d’Estudis Catalans, 2013-12-12) Guirao Abad, José P.; Sánchez Fresneda, Ruth; Valentín, Eulogio; Argüelles, Juan Carlos; Martínez-Esparza Alvargonzález, María Concepción; Bioquímica y Biología Molecular B e InmunologíaValidamycin A has been successfully applied in the fight against phytopathogenic fungi. Here, the putative antifungal effect of this pseudooligosaccharide against the prevalent human pathogen Candida albicans was examined. Validamycin A acts as a potent competitive inhibitor of the cell-wall-linked acid trehalase (Atc1p). The estimated MIC50 for the C. albicans parental strain CEY.1 was 500 mg/l. The addition of doses below MIC50 to exponentially growing CEY.1 cells caused a slight reduction in cell growth. A concentration of 1 mg/ml was required to achieve a significant degree of cell killing. The compound was stable as evidenced by the increased reduction of cell growth with increasing incubation time. A homozygous atc1delta/atc1delta mutant lacking functional Atc1p activity showed greater resistance to the drug. The antifungal power of validamycin A was limited compared with the drastic lethal action caused by exposure to amphotericin B. The endogenous content of trehalose rose significantly upon validamycin and amphotericin B addition. Neither serum-induced hypha formation nor the level of myceliation recorded in macroscopic colonies were affected by exposure to validamycin A. Our results suggest that, although validamycin A cannot be considered a clinically useful antifungal against C. albicans, its mechanism of action and antifungal properties provide the basis for designing new, clinically interesting, antifungal-related compounds.
- PublicationRestrictedGlycoconjugate expression on the cell wall of tps1/tps1 trehalose-deficient Candida albicans strain and implications for its interaction with macrophages(Oxford University Press, 2011-01-20) Vitse-Standaert, Annie; García-Peñarrubia, Pilar; Argüelles, Juan Carlos; Poulain, Daniel; Jouault, Thierry; Martínez-Esparza Alvargonzález, María Concepción; Tapia Abellán, Ana; Bioquímica y Biología Molecular B e InmunologíaThe yeast Candida albicans has developed a variety of strategies to resist macrophage killing. In yeasts, accumulation of trehalose is one of the principal defense mechanisms under stress conditions. The gene-encoding trehalose-6-phosphate synthase (TPS1), which is responsible for trehalose synthesis, is induced in response to oxidative stress, as in phagolysosomes. Mutants unable to synthesize trehalose are sensitive to oxidative stress in vitro. In mice, the TPS1-deficient strain, tps1/tps1, displays a lower infection rate than its parental strain (CAI4). We have previously demonstrated the reduced binding capacity of tps1/tps1 and its lower resistance to macrophages. At the same time, its outer cell wall layer was seen to be altered. In this study, we show that depending on the culture conditions, the tps1/tps1 strain regulates the carbohydrate metabolism in a different way to CAI4, as reflected by the enhanced β-mannosylation of cell wall components, especially at the level of the 120 kDa glycoprotein species, accessible at the cell surface of tps1/tps1 when cultured in liquid medium, but not on solid medium. This leads to changes in its surface properties, as revealed by decreased hydrophobicity, and the lower levels of ERK1/2 phosphorylation and tumor necrosis factor-α (TNF-α) production in macrophages, thus increasing the resistance to these cells. In contrast, in solid medium, in which over-glycosylation was less evident, tps1/tps1 showed similar macrophage interaction properties to CAI4, but was less resistant to killing, confirming the protective role of trehalose. Thus, the lack of trehalose is compensated by an over-glycosylation of the cell wall components in the tps1/tps1 mutant, which reduces susceptibility to killing.
- PublicationOpen AccessIdentification of fungal trehalose for the diagnosis of invasive candidiasis by mass spectrometry.(Elsevier, 2022-01-13) Mery, Alexandre; Jawhara, Samir; François, Nadine; Cornu, Marjorie; Poissy, Julien; Poulain, Daniel; Sendid, Boualem; Guerardel, Yann; Martínez-Esparza Alvargonzález, María Concepción; Bioquímica y Biología Molecular B e Inmunología
PublicationRestrictedMicafungin enhances the human macrophage response to Candida albicans through β-glucan exposure(American Society for Microbiology, 2018-04-26) Guirao-Abad, José Pedro; Sánchez-Fresneda, Ruth; Machado, Francisco; Argüelles, Juan Carlos; Martínez-Esparza Alvargonzález, María Concepción; Bioquímica y Biología Molecular B e InmunologíaMicafungin belongs to the antifungal family of echinocandins, which act as noncompetitive inhibitors of the fungal cell wall β-1,3-d-glucan synthase. Since Candida albicans is the most prevalent pathogenic fungus in humans, we study the involvement of micafungin in the modulation of the inflammatory response developed by human tissue macrophages against C. albicans The MIC for micafungin was 0.016 μg/ml on the C. albicans SC5314 standard strain. Micafungin induced a drastic reduction in the number of exponential SC5314 viable cells, with the fungicidal effect being dependent on the cellular metabolic activity. Notably, micafungin also caused a structural remodelling of the cell wall, leading to exposure of the β-glucan and chitin content on the external surface. At the higher doses used (0.05 μg/ml), the antifungal also induced the blowing up of budding yeasts. In addition, preincubation with micafungin before exposure to human tissue macrophages enhanced the secretion of tumor necrosis factor alpha (TNF-α), interleukin-17A (IL-17A), and IL-10 cytokines. Our results strongly suggest that in C. albicans treatment with micafungin, in addition to having the expected toxic antifungal effect, it potentiates the immune response, improving the interaction and activation of human macrophages, probably through the unmasking of β-glucans on the cell wall surface.- PublicationOpen AccessOptimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis(MDPI, 2019-06-06) Manca, Maria Letizia; Usach, Iris; Esteban Peris, José; Ibba, Antonella; Orrù, Germano; Valenti, Donatella; Escribano-Ferrer, Elvira; Gomez-Fernandez, Juan Carmelo; Maria Fadda, Anna; Manconi, Maria; Aranda Martínez, Francisco José; Bioquímica y Biología Molecular ANew three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.
- PublicationOpen AccessPga26 mediates filamentation and biofilm formation and is required for virulence in Candida albicans.(Blackwell Publishing Ltd., 2011-08) Laforet, Leslie; Moreno, Inmaculada; Sánchez Fresneda, Ruth; Martínez, José P.; Argüelles, Juan Carlos; Groot, Piet W.J. de; Valentín Gómez, Eulogio; Martínez-Esparza Alvargonzález, María Concepción; Bioquímica y Biología Molecular B e InmunologíaThe Candida albicans gene PGA26 encodes a small cell wall protein and is upregulated during de novo wall synthesis in protoplasts. Disruption of PGA26 caused hypersensitivity to cell wall-perturbing compounds (Calcofluor white and Congo red) and to zymolyase, which degrades the cell wall β-1,3-glucan network. However, susceptibility to caspofungin, an inhibitor of β-1,3-glucan synthesis, was decreased. In addition, pga26Δ mutants show increased susceptibility to antifungals (fluconazol, posaconazol or amphotericin B) that target the plasma membrane and have altered sensitivities to environmental (heat, osmotic and oxidative) stresses. Except for a threefold increase in β-1,6-glucan and a slightly widened outer mannoprotein layer, the cell wall composition and structure was largely unaltered. Therefore, Pga26 is important for proper cell wall integrity, but does not seem to be directly involved in the synthesis of cell wall components. Deletion of PGA26 further leads to hyperfilamentation, increased biofilm formation and reduced virulence in a mouse model of disseminated candidiasis. We propose that deletion of PGA26 may cause an imbalance in the morphological switching ability of Candida, leading to attenuated dissemination and infection.
- PublicationOpen AccessProbiotic (yogurt) containing Lactobacillus gasseri OLL2716 is effective for preventing Candida albicans-induced mucosal inflammation and proliferation in the forestomach of diabetic rats(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Terayama, Yui; Matsuura, Tetsuro; Uchida, Masayuki; Narama, Isao; Ozaki, KiyokazuOral and esophageal candidiasis sometimes leads to mucosal hyperplasia, and progresses to carcinoma. We have produced an animal model for hyperplastic mucosal candidiasis in the forestomach that has a proliferative lesion of the squamous epithelium with chronic inflammation and C. albicans infection, some of which advanced to squamous cell carcinoma. There are many reports of the antibacterial effects of probiotics, but consensus about their antifungal effect has not been reached. In the present study, we investigate whether probiotic (yogurt) containing Lactobacillus gasseri OLL2716 (LG21 yogurt) can prevent proliferative and inflammatory changes caused by C. albicans in this mucosal candidiasis animal model. Diabetes was induced in 8-week-old WBN/Kob rats by intravenous administration of alloxan. One group of diabetic rats received a saline containing C. albicans and LG21 yogurt orally (DC+LG21 group) for 30 weeks, and another group received only C. albicans (DC group) for 30 weeks. They were sacrificed at 40 weeks of age, and analyzed histopathologically. In the DC+LG21 group, squamous hyperplasia at the greater curvature was significantly milder, and the Ki-67 positive index was significantly lower compared with the DC group. Suppurative inflammation with C. albicans also tended to be suppressed at the greater curvature. These findings suggest that probiotic (yogurt) containing Lactobacillus gasseri OLL2716 can suppress squamous hyperplastic change and inflammation associated with C. albicans infection in the forestomach.
- PublicationOpen AccessThe Fungicidal Action of Micafungin is Independent on Both Oxidative Stress Generation and HOG Pathway Signaling in Candida albicans(MDPI, ) Alonso-Monge, R; Guirao_Abad, JP; Sánchez-Fresneda, R; Pla, J; Yagüe, G; Argüelles, JC; Genética y MicrobiologíaIn fungi, the Mitogen-Activated Protein kinase (MAPK) pathways sense a wide variety of environmental stimuli, leading to cell adaptation and survival. The HOG pathway plays an essential role in the pathobiology of Candida albicans, including the colonization of the gastrointestinal tract in a mouse model, virulence, and response to stress. Here, we examined the role of Hog1 in the C. albicans response to the clinically relevant antifungal Micafungin (MF), whose minimum inhibitory concentration (MIC) was identical in the parental strain (RM100) and in the isogenic homozygous mutant hog1 (0.016 mg/L). The cell viability was impaired without significant differences between the parental strain, the isogenic hog1 mutant, and the Hog1+ reintegrant. This phenotype was quite similar in a collection of hog1 mutants constructed in a different C. albicans background. MF-treated cells failed to induce a relevant increase of both reactive oxygen species (ROS) formation and activation of the mitochondrial membrane potential in parental and hog1 cells. MF was also unable to trigger any significant activation of the genes coding for the antioxidant activities catalase (CAT1) and superoxide dismutase (SOD2), as well as on the corresponding enzymatic activities, whereas a clear induction was observed in the presence of Amphotericin B (AMB), introduced as a positive control of Hog1 signaling. Furthermore, Hog1 was not phosphorylated by the addition of MF, but, notably, this echinocandin caused Mkc1 phosphorylation. Our results strongly suggest that the toxic effect of MF on C. albicans cells is not mediated by the Hog1 MAPK and is independent of the generation of an internal oxidative stress in C. albicans.
- PublicationOpen AccessThe histopathology of Candida albicans invasion in neonatal rat tissues and in the human blood-brain barrier in culture revealed by light, scanning, transmission and immunoelectron microscopy scanning(Murcia : F. Hernández, 2006) Lossinsky, A.S.; Jong, A.; Fiala, M.; Mukhtar, M.; Buttle, K.F.; Ingram, M.The present studies examined the effects of Candida albicans yeast and hyphal morphologies on tissue pathologies and transmigration properties of the fungus in two experimental models: 1) an in vivo, neonatal rat model, and 2) a cell culture model of human brain microvascular endothelial cells (ECs) (BMVEC). We inoculated a hyphae-producing strain (CAI4-URA3) and a non-hyphae-producing strain (CAI4) of C. albicans into 4-10 day old rats and BMVEC cultures. Animals were inoculated by intraperitonal (i.p.), intranasal (i.n.), oral (p.o.) and intracerebral (i.c.) routes and several tissues were examined after 24-48 hrs. Rats inoculated i.p. with the hyphae-producing strain showed pathology in the kidneys, liver, spleen, and other tissues associated with inoculation tracks of the nose, and muscle and connective tissues of the abdominal wall. Few animals inoculated i.p., however, presented evidence of meningitis. The non-hyphae phase yeast produced neither tissue pathology nor meningitis. Animals inoculated i.c. with the hyphae strain after 1 and 3 hrs expressed minimal meningitis, with an increasing neutrophillic meningitis between 4 and 18 hrs after inoculation. At 18 hrs after i.c. inoculation, however, the inflammatory foci and brain pathology were extensive and demonstrated mycelia within the lateral ventricles associated with necrosis of adjacent brain tissue. Neutrophillic meningitis at this time period was pronounced. BMVEC co-cultured 1-2 hrs with both C. albicans strains showed EC phagocytosis of hyphae and blastospores into intercellular adhesion molecule-1 (ICAM-1)-labeled caveolae suggesting a transcellular role for ICAM-1 in the internalization process of C. albicans.
- PublicationOpen AccessTrained immunity induction by the inactivated mucosal vaccine MV130 protects against experimental viral respiratory infections(Cell Press, 2022-01-04) Brandi, Paola; Conejero, Laura; Cueto, Francisco J.; Martínez Cano, Sarai; Dunphy, Gillian; Gómez, Manuel J.; Relaño, Carlos; Saz Leal, Paula; Enamorado, Michel; Quintas, Ana; Dopazo, Ana; Amores Iniesta, Joaquín; Fresno, Carlos del; Nistal Villán, Estanislao; Ardavín, Carlos; Nieto, Antonio; Casanovas, Miguel; Subiza, José Luis; Sancho, David; Sanidad AnimalMV130 is an inactivated polybacterial mucosal vaccine that confers protection to patients against recurrent respiratory infections, including those of viral etiology. However, its mechanism of action remains poorly un-derstood. Here, we find that intranasal prophylaxis with MV130 modulates the lung immune landscape and provides long-term heterologous protection against viral respiratory infections in mice. Intranasal adminis-tration of MV130 provides protection against systemic candidiasis in wild-type and Rag1-deficient mice lacking functional lymphocytes, indicative of innate immune-mediated protection. Moreover, pharmacolog-ical inhibition of trained immunity with metformin abrogates the protection conferred by MV130 against influ-enza A virus respiratory infection. MV130 induces reprogramming of both mouse bone marrow progenitor cells and in vitro human monocytes, promoting an enhanced cytokine production that relies on a metabolic shift. Our results unveil that the mucosal administration of a fully inactivated bacterial vaccine provides pro-tection against viral infections by a mechanism associated with the induction of trained immunity.