In Vitro and In Vivo Effects of 14α-Demethylase (ERG11) Depletion in Candida glabrata

ABSTRACT Sterol 14α-demethylase (ERG11) is the target enzyme of azole antifungals that are widely used for the treatment of fungal infections. Candida glabrata is known to be less susceptible to fluconazole than most Candida albicansstrains, and the incidence of C. glabrata infection has been increasing mostly in conjunction with the use of azole antifungals. Recently, it has been reported that C. glabrata can rescue the defect of ergosterol biosynthesis by incorporating cholesterol from serum. To explore the effect of inactivating Erg11p in C. glabrata, we generated mutant strains in which the ERG11 gene was placed under the control of tetracycline-regulatable promoters. In these mutants, expression of the ERG11 gene can be repressed by doxycycline (DOX). All mutants showed a growth defect in the presence of DOX. The numbers of CFU of the mutants were lowered by only 1/10 with DOX treatment. In these mutants, accumulation of 4,14-dimethylzymosterol, which differs from an accumulated abnormal sterol detected in C. albicans and Saccharomyces cerevisiae treated with fluconazole, was observed by DOX treatment. Although such phenotypes were also observed in serum-containing media by DOX treatment, they were alleviated. Furthermore, the mutant could grow in DOX-treated mice without a severe reduction in the number of cells. Thus, depleting the expression of theERG11 gene lowered the number of CFU by only 1/10 due to the accumulation of 4,14-demethylzymosterol in vitro, and it did not result in the defective growth of fungal cells in mice. These results suggested that Erg11p is not an ideal target molecule of antifungals for C. glabrata.

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In VitroandIn VivoActivities of Pterostilbene against Candida albicans Biofilms

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01583-13 ◽

2014 ◽

Vol 58 (4) ◽

pp. 2344-2355 ◽

Cited By ~ 47

Author(s):

De-Dong Li ◽

Lan-Xue Zhao ◽

Eleftherios Mylonakis ◽

Gan-Hai Hu ◽

Yong Zou ◽

...

Keyword(s):

Candida Albicans ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Growth Defect ◽

Ergosterol Biosynthesis ◽

Infection Model ◽

Content Type ◽

Camp Pathway

ABSTRACTPterostilbene (PTE) is a stilbene-derived phytoalexin that originates from several natural plant sources. In this study, we evaluated the activity of PTE againstCandida albicansbiofilms and explored the underlying mechanisms. In 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assays, biofilm biomass measurement, confocal laser scanning microscopy, and scanning electron microscopy, we found that ≤16 μg/ml PTE had a significant effect againstC. albicansbiofilmsin vitro, while it had no fungicidal effect on planktonicC. albicanscells, which suggested a unique antibiofilm effect of PTE. Then we found that PTE could inhibit biofilm formation and destroy the maintenance of mature biofilms. At 4 μg/ml, PTE decreased cellular surface hydrophobicity (CSH) and suppressed hyphal formation. Gene expression microarrays and real-time reverse transcription-PCR showed that exposure ofC. albicansto 16 μg/ml PTE altered the expression of genes that function in morphological transition, ergosterol biosynthesis, oxidoreductase activity, and cell surface and protein unfolding processes (heat shock proteins). Filamentation-related genes, especially those regulated by the Ras/cyclic AMP (cAMP) pathway, includingECE1,ALS3,HWP1,HGC1, andRAS1itself, were downregulated upon PTE treatment, indicating that the antibiofilm effect of PTE was related to the Ras/cAMP pathway. Then, we found that the addition of exogenous cAMP reverted the PTE-induced filamentous growth defect. Finally, with a rat central venous catheter infection model, we confirmed thein vivoactivity of PTE againstC. albicansbiofilms. Collectively, PTE had strong activities againstC. albicansbiofilms bothin vitroandin vivo, and these activities were associated with the Ras/cAMP pathway.

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Critical Assessment of Cell Wall Integrity Factors Contributing to in vivo Echinocandin Tolerance and Resistance in Candida glabrata

Frontiers in Microbiology ◽

10.3389/fmicb.2021.702779 ◽

2021 ◽

Vol 12 ◽

Author(s):

Rocio Garcia-Rubio ◽

Rosa Y. Hernandez ◽

Alissa Clear ◽

Kelley R. Healey ◽

Erika Shor ◽

...

Keyword(s):

Cell Wall ◽

Candida Glabrata ◽

Fungal Infections ◽

Critical Role ◽

Cell Wall Integrity ◽

Fungal Cell ◽

Fungal Host

Fungal infections are on the rise, and emergence of drug-resistant Candida strains refractory to treatment is particularly alarming. Resistance to azole class antifungals, which have been extensively used worldwide for several decades, is so high in several prevalent fungal pathogens, that another drug class, the echinocandins, is now recommended as a first line antifungal treatment. However, resistance to echinocandins is also prominent, particularly in certain species, such as Candida glabrata. The echinocandins target 1,3-β-glucan synthase (GS), the enzyme responsible for producing 1,3-β-glucans, a major component of the fungal cell wall. Although echinocandins are considered fungicidal, C. glabrata exhibits echinocandin tolerance both in vitro and in vivo, where a subset of the cells survives and facilitates the emergence of echinocandin-resistant mutants, which are responsible for clinical failure. Despite this critical role of echinocandin tolerance, its mechanisms are still not well understood. Additionally, most studies of tolerance are conducted in vitro and are thus not able to recapitulate the fungal-host interaction. In this study, we focused on the role of cell wall integrity factors in echinocandin tolerance in C. glabrata. We identified three genes involved in the maintenance of cell wall integrity – YPS1, YPK2, and SLT2 – that promote echinocandin tolerance both in vitro and in a mouse model of gastrointestinal (GI) colonization. In particular, we show that mice colonized with strains carrying deletions of these genes were more effectively sterilized by daily caspofungin treatment relative to mice colonized with the wild-type parental strain. Furthermore, consistent with a role of tolerant cells serving as a reservoir for generating resistant mutations, a reduction in tolerance was associated with a reduction in the emergence of resistant strains. Finally, reduced susceptibility in these strains was due both to the well described FKS-dependent mechanisms and as yet unknown, FKS-independent mechanisms. Together, these results shed light on the importance of cell wall integrity maintenance in echinocandin tolerance and emergence of resistance and lay the foundation for future studies of the factors described herein.

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Pharmacology of 5-HT1A Receptors: Critical Aspects

CNS Spectrums ◽

10.1017/s1092852900006635 ◽

1998 ◽

Vol 3 (10) ◽

pp. 17-38 ◽

Cited By ~ 3

Author(s):

Franco Borsini

Keyword(s):

Receptor Subtypes ◽

Laboratory Conditions ◽

In Vivo Effects ◽

Critical Aspects

AbstractMyriad difficulties exist in analyzing the pharmacology of the serotonin 1A (5-HT1A) receptor. The receptor may demonstrate a different activity depending on the tissue or species used for analysis, the agent used, laboratory conditions, and differences between in vitro and in vivo effects of compounds. Affinity for 5-HT receptors also varies widely, presenting difficulties in drawing definitive conclusions on affinity values for various compounds. At least two possibilities exist to explain the diversity of pharmacology of 5-HT receptors. First, it is possible that different 5-HT1A receptor subtypes exist. Second, the 5-HT1A receptors may play a far more complex role than previously believed.

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Conifers Phytochemicals: A Valuable Forest with Therapeutic Potential

Molecules ◽

10.3390/molecules26103005 ◽

2021 ◽

Vol 26 (10) ◽

pp. 3005

Author(s):

Kanchan Bhardwaj ◽

Ana Sanches Silva ◽

Maria Atanassova ◽

Rohit Sharma ◽

Eugenie Nepovimova ◽

...

Keyword(s):

Experimental Data ◽

Potential Role ◽

Therapeutic Potential ◽

Fungal Infections ◽

Cell Damage ◽

Cancer Growth ◽

Naturally Occurring ◽

Antioxidant Effects

Conifers have long been recognized for their therapeutic potential in different disorders. Alkaloids, terpenes and polyphenols are the most abundant naturally occurring phytochemicals in these plants. Here, we provide an overview of the phytochemistry and related commercial products obtained from conifers. The pharmacological actions of different phytochemicals present in conifers against bacterial and fungal infections, cancer, diabetes and cardiovascular diseases are also reviewed. Data obtained from experimental and clinical studies performed to date clearly underline that such compounds exert promising antioxidant effects, being able to inhibit cell damage, cancer growth, inflammation and the onset of neurodegenerative diseases. Therefore, an attempt has been made with the intent to highlight the importance of conifer-derived extracts for pharmacological purposes, with the support of relevant in vitro and in vivo experimental data. In short, this review comprehends the information published to date related to conifers’ phytochemicals and illustrates their potential role as drugs.

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Techniques for the Assessment of In Vitro and In Vivo Antifungal Combinations

Journal of Fungi ◽

10.3390/jof7020113 ◽

2021 ◽

Vol 7 (2) ◽

pp. 113

Author(s):

Anne-Laure Bidaud ◽

Patrick Schwarz ◽

Guillaume Herbreteau ◽

Eric Dannaoui

Keyword(s):

Animal Models ◽

Fungal Infections ◽

Acquired Resistance ◽

Adequate Treatment ◽

Combination Treatments ◽

Target Organs ◽

Fungal Load ◽

Time Kill

Systemic fungal infections are associated with high mortality rates despite adequate treatment. Moreover, acquired resistance to antifungals is increasing, which further complicates the therapeutic management. One strategy to overcome antifungal resistance is to use antifungal combinations. In vitro, several techniques are used to assess drug interactions, such as the broth microdilution checkerboard, agar-diffusion methods, and time-kill curves. Currently, the most widely used technique is the checkerboard method. The aim of all these techniques is to determine if the interaction between antifungal agents is synergistic, indifferent, or antagonistic. However, the interpretation of the results remains difficult. Several methods of analysis can be used, based on different theories. The most commonly used method is the calculation of the fractional inhibitory concentration index. Determination of the usefulness of combination treatments in patients needs well-conducted clinical trials, which are difficult. It is therefore important to study antifungal combinations in vivo, in experimental animal models of fungal infections. Although mammalian models have mostly been used, new alternative animal models in invertebrates look promising. To evaluate the antifungal efficacy, the most commonly used criteria are the mortality rate and the fungal load in the target organs.

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Review of T-2307, an Investigational Agent That Causes Collapse of Fungal Mitochondrial Membrane Potential

Journal of Fungi ◽

10.3390/jof7020130 ◽

2021 ◽

Vol 7 (2) ◽

pp. 130

Author(s):

Nathan P. Wiederhold

Keyword(s):

Membrane Potential ◽

Mitochondrial Membrane Potential ◽

Candida Species ◽

Mammalian Cells ◽

Mitochondrial Membrane ◽

Fungal Infections ◽

Published Data ◽

Candida Auris

Invasive infections caused by Candida that are resistant to clinically available antifungals are of increasing concern. Increasing rates of fluconazole resistance in non-albicans Candida species have been documented in multiple countries on several continents. This situation has been further exacerbated over the last several years by Candida auris, as isolates of this emerging pathogen that are often resistant to multiple antifungals. T-2307 is an aromatic diamidine currently in development for the treatment of invasive fungal infections. This agent has been shown to selectively cause the collapse of the mitochondrial membrane potential in yeasts when compared to mammalian cells. In vitro activity has been demonstrated against Candida species, including C. albicans, C. glabrata, and C. auris strains, which are resistant to azole and echinocandin antifungals. Activity has also been reported against Cryptococcus species, and this has translated into in vivo efficacy in experimental models of invasive candidiasis and cryptococcosis. However, little is known regarding the clinical efficacy and safety of this agent, as published data from studies involving humans are not currently available.

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Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

Eukaryotic Cell ◽

10.1128/ec.00049-07 ◽

2007 ◽

Vol 6 (6) ◽

pp. 931-939 ◽

Cited By ~ 96

Author(s):

Fang Li ◽

Michael J. Svarovsky ◽

Amy J. Karlsson ◽

Joel P. Wagner ◽

Karen Marchillo ◽

...

Keyword(s):

Candida Albicans ◽

Cell Adhesion ◽

Biofilm Formation ◽

Fungal Infections ◽

Gene Dosage ◽

Venous Catheter ◽

Flow Chamber ◽

Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

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In vitro evaluation of estrogenic, antiestrogenic and antitumor effects of amentoflavone

Human & Experimental Toxicology ◽

10.1177/0960327121999454 ◽

2021 ◽

pp. 096032712199945

Author(s):

AT Aliyev ◽

S Ozcan-Sezer ◽

A Akdemir ◽

H Gurer-Orhan

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Antitumor Effects ◽

Antiestrogenic Activity ◽

Er Positive ◽

In Vivo Effects ◽

Mcf 7

Apigenin, a flavonoid, is reported to act as an estrogen receptor (ER) agonist and inhibit aromatase enzyme. However, amentoflavone, a biflavonoid bearing two apigenin molecules, has not been evaluated for its endocrine modulatory effects. Besides, it is highly consumed by young people to build muscles, enhance mood and lose weight. In the present study, apigenin was used as a reference molecule and ER mediated as well as ER-independent estrogenic/antiestrogenic activity of amentoflavone was investigated. Antitumor activity of amentoflavone was also investigated in both ER positive (MCF-7 BUS) and triple-negative (MDA-MB-231) breast cancer cells and its cytotoxicity was evaluated in human breast epithelial cells (MCF-10A). Our data confirmed ER agonist, aromatase inhibitory and cytotoxic effects of apigenin in breast cancer cells, where no ER mediated estrogenic effect and physiologically irrelevant, slight, aromatase inhibition was found for amentoflavone. Although selective cytotoxicity of amentoflavone was found in MCF-7 BUS cells, it does not seem to be an alternative to the present cytotoxic drugs. Therefore, neither an adverse effect, mediated by an estrogenic/antiestrogenic effect of amentoflavone nor a therapeutical benefit would be expected from amentoflavone. Further studies could be performed to investigate its in vivo effects.

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Effects of Bacterial CLPB Protein Fragments on Food Intake and PYY Secretion

Nutrients ◽

10.3390/nu13072223 ◽

2021 ◽

Vol 13 (7) ◽

pp. 2223

Author(s):

Manon Dominique ◽

Nicolas Lucas ◽

Romain Legrand ◽

Illona-Marie Bouleté ◽

Christine Bôle-Feysot ◽

...

Keyword(s):

Food Intake ◽

Peptide Yy ◽

Molecular Mimicry ◽

Potential Effect ◽

In Vivo Studies ◽

Sprague Dawley ◽

E Coli ◽

In Vivo Effects

CLPB (Caseinolytic peptidase B) protein is a conformational mimetic of α-MSH, an anorectic hormone. Previous in vivo studies have already shown the potential effect of CLPB protein on food intake and on the production of peptide YY (PYY) by injection of E. coli wild type (WT) or E. coli ΔClpB. However, until now, no study has shown its direct effect on food intake. Furthermore, this protein can fragment naturally. Therefore, the aim of this study was (i) to evaluate the in vitro effects of CLPB fragments on PYY production; and (ii) to test the in vivo effects of a CLPB fragment sharing molecular mimicry with α-MSH (CLPB25) compared to natural fragments of the CLPB protein (CLPB96). To do that, a primary culture of intestinal mucosal cells from male Sprague–Dawley rats was incubated with proteins extracted from E. coli WT and ΔCLPB after fragmentation with trypsin or after a heat treatment of the CLPB protein. PYY secretion was measured by ELISA. CLPB fragments were analyzed by Western Blot using anti-α-MSH antibodies. In vivo effects of the CLPB protein on food intake were evaluated by intraperitoneal injections in male C57Bl/6 and ob/ob mice using the BioDAQ® system. The natural CLPB96 fragmentation increased PYY production in vitro and significantly decreased cumulative food intake from 2 h in C57Bl/6 and ob/ob mice on the contrary to CLPB25. Therefore, the anorexigenic effect of CLPB is likely the consequence of enhanced PYY secretion.

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Dual Role of Interleukin-10 in Murine NZB/W F1 Lupus

International Journal of Molecular Sciences ◽

10.3390/ijms22031347 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1347

Author(s):

Anaïs Amend ◽

Natalie Wickli ◽

Anna-Lena Schäfer ◽

Dalina T. L. Sprenger ◽

Rudolf A. Manz ◽

...

Keyword(s):

B Cell ◽

Disease Model ◽

Interleukin 10 ◽

Immune Functions ◽

Murine Lupus ◽

Anti Inflammatory ◽

In Vivo Effects

As a key anti-inflammatory cytokine, IL-10 is crucial in preventing inflammatory and autoimmune diseases. However, in human and murine lupus, its role remains controversial. Our aim was to understand regulation and immunologic effects of IL-10 on different immune functions in the setting of lupus. This was explored in lupus-prone NZB/W F1 mice in vitro and vivo to understand IL-10 effects on individual immune cells as well as in the complex in vivo setting. We found pleiotropic IL-10 expression that largely increased with progressing lupus, while IL-10 receptor (IL-10R) levels remained relatively stable. In vitro experiments revealed pro- and anti-inflammatory IL-10 effects. Particularly, IL-10 decreased pro-inflammatory cytokines and slowed B cell proliferation, thereby triggering plasma cell differentiation. The frequent co-expression of ICOS, IL-21 and cMAF suggests that IL-10-producing CD4 T cells are important B cell helpers in this context. In vitro and in vivo effects of IL-10 were not fully concordant. In vivo IL-10R blockade slightly accelerated clinical lupus manifestations and immune dysregulation. Altogether, our side-by-side in vitro and in vivo comparison of the influence of IL-10 on different aspects of immunity shows that IL-10 has dual effects. Our results further reveal that the overall outcome may depend on the interplay of different factors such as target cell, inflammatory and stimulatory microenvironment, disease model and state. A comprehensive understanding of such influences is important to exploit IL-10 as a therapeutic target.

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