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Specht CA, Lam WC, Hester MM, Lourenco D, Levitz SM, Lodge JK, Upadhya R. Chitosan-Deficient Cryptococcus as Whole-Cell Vaccines. Methods Mol Biol 2024; 2775:393-410. [PMID: 38758333 DOI: 10.1007/978-1-0716-3722-7_27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Creating a safe and effective vaccine against infection by the fungal pathogen Cryptococcus neoformans is an appealing option that complements the discovery of new small molecule antifungals. Recent animal studies have yielded promising results for a variety of vaccines that include live-attenuated and heat-killed whole-cell vaccines, as well as subunit vaccines formulated around recombinant proteins. Some of the recombinantly engineered cryptococcal mutants in the chitosan biosynthesis pathway are avirulent and very effective at conferring protective immunity. Mice vaccinated with these avirulent chitosan-deficient strains are protected from a lethal pulmonary infection with C. neoformans strain KN99. Heat-killed derivatives of the vaccination strains are likewise effective in a murine model of infection. The efficacy of these whole-cell vaccines, however, is dependent on a number of factors, including the inoculation dose, route of vaccination, frequency of vaccination, and the specific mouse strain used in the study. Here, we present detailed methods for identifying and optimizing various factors influencing vaccine potency and efficacy in various inbred mouse strains using a chitosan-deficient cda1Δcda2Δcda3Δ strain as a whole-cell vaccine candidate. This chapter describes the protocols for immunizing three different laboratory mouse strains with vaccination regimens that use intranasal, orotracheal, and subcutaneous vaccination routes after the animals were sedated using two different types of anesthesia.
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Affiliation(s)
- Charles A Specht
- Department of Medicine, The University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Woei C Lam
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
- Pfizer STL, Chesterfield, MO, USA
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Maureen M Hester
- Department of Medicine, The University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Diana Lourenco
- Department of Medicine, The University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Stuart M Levitz
- Department of Medicine, The University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Jennifer K Lodge
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Rajendra Upadhya
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA.
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2
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Deng H, Song J, Huang Y, Yang C, Zang X, Zhou Y, Li H, Dai B, Xue X. Combating increased antifungal drug resistance in Cryptococcus, what should we do in the future? Acta Biochim Biophys Sin (Shanghai) 2023; 55:540-547. [PMID: 36815374 DOI: 10.3724/abbs.2023011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Few therapeutic drugs and increased drug resistance have aggravated the current treatment difficulties of Cryptococcus in recent years. To better understand the antifungal drug resistance mechanism and treatment strategy of cryptococcosis. In this review, by combining the fundamental features of Cryptococcus reproduction leading to changes in its genome, we review recent research into the mechanism of four current anti-cryptococcal agents, coupled with new therapeutic strategies and the application of advanced technologies WGS and CRISPR-Cas9 in this field, hoping to provide a broad idea for the future clinical therapy of cryptococcosis.
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Affiliation(s)
- Hengyu Deng
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Jialin Song
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Yemei Huang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Chen Yang
- Department of Laboratory Medicine, the First Medical Centre, Chinese PLA General Hospital, Beijing 100853, China
| | - Xuelei Zang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Yangyu Zhou
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Hongli Li
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Bin Dai
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Xinying Xue
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China.,Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
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3
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Alves V, Araújo GR, Frases S. Off-label treatments as potential accelerators in the search for the ideal antifungal treatment of cryptococcosis. Future Microbiol 2023; 18:127-135. [PMID: 36688321 DOI: 10.2217/fmb-2022-0122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cryptococcosis is an opportunistic mycosis that mainly affects immunosuppressed patients. The treatment is a combination of three antifungal agents: amphotericin B, 5-flucytosine and fluconazole. However, these drugs have many disadvantages, such as high nephrotoxicity, marketing bans in some countries and fungal resistance. One of the solutions to find possible new drugs is pharmacological repositioning. This work presents repositioned drugs as an alternative for new antifungal therapies for cryptococcosis. All the studies here were performed in vitro or in animal models, except for sertraline, which reached phase III in humans. There is still no pharmacological repositioning approval for cryptococcosis in humans, though this review shows the potential of repurposing as a rapid approach to finding new agents to treat cryptococcosis.
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Affiliation(s)
- Vinicius Alves
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, 21941902, Brazil
| | - Glauber Rs Araújo
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, 21941902, Brazil
| | - Susana Frases
- Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, 21941902, Brazil
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4
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5
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Antifungal activity of dendritic cell lysosomal proteins against Cryptococcus neoformans. Sci Rep 2021; 11:13619. [PMID: 34193926 PMCID: PMC8245489 DOI: 10.1038/s41598-021-92991-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 06/14/2021] [Indexed: 12/17/2022] Open
Abstract
Cryptococcal meningitis is a life-threatening disease among immune compromised individuals that is caused by the opportunistic fungal pathogen Cryptococcus neoformans. Previous studies have shown that the fungus is phagocytosed by dendritic cells (DCs) and trafficked to the lysosome where it is killed by both oxidative and non-oxidative mechanisms. While certain molecules from the lysosome are known to kill or inhibit the growth of C. neoformans, the lysosome is an organelle containing many different proteins and enzymes that are designed to degrade phagocytosed material. We hypothesized that multiple lysosomal components, including cysteine proteases and antimicrobial peptides, could inhibit the growth of C. neoformans. Our study identified the contents of the DC lysosome and examined the anti-cryptococcal properties of different proteins found within the lysosome. Results showed several DC lysosomal proteins affected the growth of C. neoformans in vitro. The proteins that killed or inhibited the fungus did so in a dose-dependent manner. Furthermore, the concentration of protein needed for cryptococcal inhibition was found to be non-cytotoxic to mammalian cells. These data show that many DC lysosomal proteins have antifungal activity and have potential as immune-based therapeutics.
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6
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Perlatti B, Lan N, Xiang M, Earp CE, Spraker JE, Harvey CJB, Nichols CB, Alspaugh JA, Gloer JB, Bills GF. Anti-cryptococcal activity of preussolides A and B, phosphoethanolamine-substituted 24-membered macrolides, and leptosin C from coprophilous isolates of Preussia typharum. J Ind Microbiol Biotechnol 2021; 48:6152282. [PMID: 33640980 PMCID: PMC8788809 DOI: 10.1093/jimb/kuab022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/13/2021] [Indexed: 11/13/2022]
Abstract
Cryptococcus neoformans is a serious human pathogen with limited options for treatment. We have interrogated extracts from fungal fermentations to find Cryptococcus-inhibiting natural products using assays for growth inhibition and differential thermosensitivity. Extracts from fermentations of four fungal strains from wild and domestic animal dung from Arkansas and West Virginia, USA were identified as Preussia typharum. The extracts exhibited two antifungal regions. Purification of one region yielded new 24-carbon macrolides incorporating both a phosphoethanolamine unit and a bridging tetrahydrofuran ring. The structures of these metabolites were established mainly by analysis of high-resolution mass spectrometry and 2D NMR data. Relative configurations were assigned using NOESY data, and the structure assignments were supported by NMR comparison with similar compounds. These new metabolites are designated preussolides A and B. The second active region was caused by the cytotoxin, leptosin C. Genome sequencing of the four strains revealed biosynthetic gene clusters consistent with those known to encode phosphoethanolamine-bearing polyketide macrolides and the biosynthesis of dimeric epipolythiodioxopiperazines. All three compounds showed moderate to potent and selective antifungal activity toward the pathogenic yeast C. neoformans.
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Affiliation(s)
- Bruno Perlatti
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, USA
| | - Nan Lan
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, USA
| | - Meichun Xiang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No 3 Park 1, Beichen West Road, Chaoyang District, Beijing 100101, China
| | - Cody E Earp
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | - Connie B Nichols
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - J Andrew Alspaugh
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - James B Gloer
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | - Gerald F Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, USA
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7
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Silva E Souza E, Barcellos VDA, Sbaraini N, Reuwsaat JCV, Schneider RDO, da Silva AC, Garcia AWA, von Poser GL, Barbosa EG, Lima JPMS, Vainstein MH. A Plumieridine-Rich Fraction From Allamanda polyantha Inhibits Chitinolytic Activity and Exhibits Antifungal Properties Against Cryptococcus neoformans. Front Microbiol 2020; 11:2058. [PMID: 32983042 PMCID: PMC7483551 DOI: 10.3389/fmicb.2020.02058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 08/05/2020] [Indexed: 12/28/2022] Open
Abstract
Cryptococcosis is a fungal infection caused mainly by the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii. The infection initiates with the inhalation of propagules that are then deposited in the lungs. If not properly treated, cryptococci cells can disseminate and reach the central nervous system. The current recommended treatment for cryptococcosis employs a three-stage regimen, with the administration of amphotericin B, flucytosine and fluconazole. Although effective, these drugs are often unavailable worldwide, can lead to resistance development, and may display toxic effects on the patients. Thus, new drugs for cryptococcosis treatment are needed. Recently, an iridoid named plumieridine was found in Allamanda polyantha seed extract; it exhibited antifungal activity against C. neoformans with a MIC of 250 μg/mL. To address the mode of action of plumieridine, several in silico and in vitro experiments were performed. Through a ligand-based a virtual screening approach, chitinases were identified as potential targets. Confirmatory in vitro assays showed that C. neoformans cell-free supernatant incubated with plumieridine displayed reduced chitinase activity, while chitinolytic activity was not inhibited in the insoluble cell fraction. Additionally, confocal microscopy revealed changes in the distribution of chitooligomers in the cryptococcal cell wall, from a polarized to a diffuse cell pattern state. Remarkably, further assays have shown that plumieridine can also inhibit the chitinolytic activity from the supernatant and cell-free extracts of bacteria, insect and mouse-derived macrophage cells (J774.A1). Together, our results suggest that plumieridine can be a broad-spectrum chitinase inhibitor.
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Affiliation(s)
- Eden Silva E Souza
- Bioinformatics Multidisciplinary Environment, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | | | - Nicolau Sbaraini
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | - Adriana Corrêa da Silva
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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Hunsaker EW, McAuliffe KJ, Franz KJ. Fluconazole analogues with metal-binding motifs impact metal-dependent processes and demonstrate antifungal activity in Candida albicans. J Biol Inorg Chem 2020; 25:729-745. [PMID: 32542530 PMCID: PMC7415656 DOI: 10.1007/s00775-020-01796-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/25/2020] [Indexed: 12/28/2022]
Abstract
Azole antifungals are an important class of antifungal drugs due to their low cost, ability to be administered orally, and broad-spectrum activity. However, their widespread and long-term use have given rise to adaptation mechanisms that render these compounds less effective against common fungal pathogens, including Candida albicans. New antifungals are desperately needed as drug-resistant strains become more prevalent. We recently showed that copper supplementation potentiates the activity of the azole antifungal fluconazole against the opportunistic fungal pathogen C. albicans. Here, we report eight new azole analogues derived from fluconazole in which one triazole group has been replaced with a metal-binding group, a strategy designed to enhance potentiation of azole antifungal activity by copper. The bioactivity of all eight compounds was tested and compared to that of fluconazole. Three of the analogues showed activity against C. albicans and two had lower levels of trailing growth. One compound, Flu-TSCZ, was found to impact the levels, speciation, and bioavailability of cellular metals.
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Affiliation(s)
- Elizabeth W Hunsaker
- Department of Chemistry, French Family Science Center, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Katherine J McAuliffe
- Department of Chemistry, French Family Science Center, Duke University, 124 Science Drive, Durham, NC, 27708, USA
| | - Katherine J Franz
- Department of Chemistry, French Family Science Center, Duke University, 124 Science Drive, Durham, NC, 27708, USA.
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9
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The Added Value of Longitudinal Imaging for Preclinical In Vivo Efficacy Testing of Therapeutic Compounds against Cerebral Cryptococcosis. Antimicrob Agents Chemother 2020; 64:AAC.00070-20. [PMID: 32284382 DOI: 10.1128/aac.00070-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/04/2020] [Indexed: 02/07/2023] Open
Abstract
Brain infections with Cryptococcus neoformans are associated with significant morbidity and mortality. Cryptococcosis typically presents as meningoencephalitis or fungal mass lesions called cryptococcomas. Despite frequent in vitro discoveries of promising novel antifungals, the clinical need for drugs that can more efficiently treat these brain infections remains. A crucial step in drug development is the evaluation of in vivo drug efficacy in animal models. This mainly relies on survival studies or postmortem analyses in large groups of animals, but these techniques only provide information on specific organs of interest at predefined time points. In this proof-of-concept study, we validated the use of noninvasive preclinical imaging to obtain longitudinal information on the therapeutic efficacy of amphotericin B or fluconazole monotherapy in meningoencephalitis and cryptococcoma mouse models. Bioluminescence imaging enabled the rapid in vitro and in vivo evaluation of drug efficacy, while complementary high-resolution anatomical information obtained by magnetic resonance imaging of the brain allowed a precise assessment of the extent of infection and lesion growth rates. We demonstrated a good correlation between both imaging readouts and the fungal burden in various organs. Moreover, we identified potential pitfalls associated with the interpretation of therapeutic efficacy based solely on postmortem studies, demonstrating the added value of this noninvasive dual imaging approach compared to standard mortality curves or fungal load endpoints. This novel preclinical imaging platform provides insights in the dynamic aspects of the therapeutic response and facilitates a more efficient and accurate translation of promising antifungal compounds from bench to bedside.
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10
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Fenbendazole Controls In Vitro Growth, Virulence Potential, and Animal Infection in the Cryptococcus Model. Antimicrob Agents Chemother 2020; 64:AAC.00286-20. [PMID: 32253211 DOI: 10.1128/aac.00286-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/29/2020] [Indexed: 12/17/2022] Open
Abstract
The human diseases caused by the fungal pathogens Cryptococcus neoformans and Cryptococcus gattii are associated with high indices of mortality and toxic and/or cost-prohibitive therapeutic protocols. The need for affordable antifungals to combat cryptococcal disease is unquestionable. Previous studies suggested benzimidazoles as promising anticryptococcal agents combining low cost and high antifungal efficacy, but their therapeutic potential has not been demonstrated so far. In this study, we investigated the antifungal potential of fenbendazole, the most effective anticryptococcal benzimidazole. Fenbendazole was inhibitory against 17 different isolates of C. neoformans and C. gattii at a low concentration. The mechanism of anticryptococcal activity of fenbendazole involved microtubule disorganization, as previously described for human parasites. In combination with fenbendazole, the concentrations of the standard antifungal amphotericin B required to control cryptococcal growth were lower than those required when this antifungal was used alone. Fenbendazole was not toxic to mammalian cells. During macrophage infection, the anticryptococcal effects of fenbendazole included inhibition of intracellular proliferation rates and reduced phagocytic escape through vomocytosis. Fenbendazole deeply affected the cryptococcal capsule. In a mouse model of cryptococcosis, the efficacy of fenbendazole to control animal mortality was similar to that observed for amphotericin B. These results indicate that fenbendazole is a promising candidate for the future development of an efficient and affordable therapeutic tool to combat cryptococcosis.
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11
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Identification of Off-Patent Drugs That Show Synergism with Amphotericin B or That Present Antifungal Action against Cryptococcus neoformans and Candida spp. Antimicrob Agents Chemother 2020; 64:AAC.01921-19. [PMID: 31988099 DOI: 10.1128/aac.01921-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 01/18/2020] [Indexed: 12/11/2022] Open
Abstract
Amphotericin B (AmB) is the antifungal with the strongest fungicidal activity, but its use has several limitations, mainly associated with its toxicity. Although some lipidic and liposomal formulations that present reduced toxicity are available, their price limits their application in developing countries. Flucytosine (5FC) has shown synergistic effect with AmB for treatment of some fungal infections, such as cryptococcosis, but again, its price is a limitation for its use in many regions. In the present work, we aimed to identify new drugs that have a minor effect on Cryptococcus neoformans, reducing its growth in the presence of subinhibitory concentrations of AmB. In the initial screening, we found fourteen drugs that had this pattern. Later, checkerboard assays of selected compounds, such as erythromycin, riluzole, nortriptyline, chenodiol, nisoldipine, promazine, chlorcyclizine, cloperastine, and glimepiride, were performed and all of them confirmed for their synergistic effect (fractional inhibitory concentration index [FICI] < 0.5). Additionally, toxicity of these drugs in combination with AmB was tested in mammalian cells and in zebrafish embryos. Harmless compounds, such as the antibiotic erythromycin, were found to have synergic activity with AmB, not only against C. neoformans but also against some Candida spp., in particular against Candida albicans In parallel, we identified drugs that had antifungal activity against C. neoformans and found 43 drugs that completely inhibited the growth of this fungus, such as ciclopirox and auranofin. Our results expand our knowledge about antifungal compounds and open new perspectives in the treatment of invasive mycosis based on repurposing off-patent drugs.
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Derivatives of the Antimalarial Drug Mefloquine Are Broad-Spectrum Antifungal Molecules with Activity against Drug-Resistant Clinical Isolates. Antimicrob Agents Chemother 2020; 64:AAC.02331-19. [PMID: 31907188 DOI: 10.1128/aac.02331-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 12/20/2019] [Indexed: 12/21/2022] Open
Abstract
The antifungal pharmacopeia is critically small, particularly in light of the recent emergence of multidrug-resistant pathogens, such as Candida auris Here, we report that derivatives of the antimalarial drug mefloquine have broad-spectrum antifungal activity against pathogenic yeasts and molds. In addition, the mefloquine derivatives have activity against clinical isolates that are resistant to one or more of the three classes of antifungal drugs currently used to treat invasive fungal infections, indicating that they have a novel mechanism of action. Importantly, the in vitro toxicity profiles obtained using human cell lines indicated that the toxicity profiles of the mefloquine derivatives are very similar to those of the parent mefloquine, despite being up to 64-fold more active against fungal cells. In addition to direct antifungal activity, subinhibitory concentrations of the mefloquine derivatives inhibited the expression of virulence traits, including filamentation in Candida albicans and capsule formation/melanization in Cryptococcus neoformans Mode/mechanism-of-action experiments indicated that the mefloquine derivatives interfere with both mitochondrial and vacuolar function as part of a multitarget mechanism of action. The broad-spectrum scope of activity, blood-brain barrier penetration, and large number of previously synthesized analogs available combine to support the further optimization and development of the antifungal activity of this general class of drug-like molecules.
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Krummenauer ME, Lopes W, Garcia AWA, Schrank A, Gnoatto SCB, Kawano DF, Vainstein MH. A Highly Active Triterpene Derivative Capable |of Biofilm Damage to Control Cryptococcus spp. Biomolecules 2019; 9:E831. [PMID: 31817559 PMCID: PMC6995603 DOI: 10.3390/biom9120831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus neoformans is an encapsulated yeast responsible for more than 180,000 deaths per year. The standard therapeutic approach against cryptococcosis is a combination of amphotericin B with flucytosine. In countries where cryptococcosis is most prevalent, 5-fluorocytosine is rarely available, and amphotericin B requires intravenous administration. C. neoformans biofilm formation is related to increased drug resistance, which is an important outcome for hospitalized patients. Here, we describe new molecules with anti-cryptococcal activity. A collection of 66 semisynthetic derivatives of ursolic acid and betulinic acid was tested against mature biofilms of C. neoformans at 25 µM. Out of these, eight derivatives including terpenes, benzazoles, flavonoids, and quinolines were able to cause damage and eradicate mature biofilms. Four terpene compounds demonstrated significative growth inhibition of C. neoformans. Our study identified a pentacyclic triterpenoid derived from betulinic acid (LAFIS13) as a potential drug for anti-cryptococcal treatment. This compound appears to be highly active with low toxicity at minimal inhibitory concentration and capable of biofilm eradication.
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Affiliation(s)
- Maria E. Krummenauer
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil; (M.E.K.); (W.L.); (A.W.A.G.); (A.S.)
| | - William Lopes
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil; (M.E.K.); (W.L.); (A.W.A.G.); (A.S.)
| | - Ane W. A. Garcia
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil; (M.E.K.); (W.L.); (A.W.A.G.); (A.S.)
| | - Augusto Schrank
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil; (M.E.K.); (W.L.); (A.W.A.G.); (A.S.)
| | - Simone C. B. Gnoatto
- Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 90610-000, Brazil;
| | - Daniel F. Kawano
- Faculdade de Ciências Farmacêuticas, Universidade Estadual de Campinas, Campinas, São Paulo 13083-871, Brazil;
| | - Marilene H. Vainstein
- Centro de Biotecnologia, PPGBCM, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91501-970, Brazil; (M.E.K.); (W.L.); (A.W.A.G.); (A.S.)
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Rudman J, Evans RJ, Johnston SA. Are macrophages the heroes or villains during cryptococcosis? Fungal Genet Biol 2019; 132:103261. [DOI: 10.1016/j.fgb.2019.103261] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/06/2019] [Accepted: 08/06/2019] [Indexed: 10/26/2022]
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15
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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16
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Host Carbon Dioxide Concentration Is an Independent Stress for Cryptococcus neoformans That Affects Virulence and Antifungal Susceptibility. mBio 2019; 10:mBio.01410-19. [PMID: 31266878 PMCID: PMC6606813 DOI: 10.1128/mbio.01410-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The ability of Cryptococcus neoformans to cause disease in humans varies significantly among strains with highly related genotypes. In general, environmental isolates of pathogenic species such as Cryptococcus neoformans var. grubii have reduced virulence relative to clinical isolates, despite having no differences in the expression of the canonical virulence traits (high-temperature growth, melanization, and capsule formation). In this observation, we report that environmental isolates of C. neoformans tolerate host CO2 concentrations poorly compared to clinical isolates and that CO2 tolerance correlates well with the ability of the isolates to cause disease in mammals. Initial experiments also suggest that CO2 tolerance is particularly important for dissemination of C. neoformans from the lung to the brain. Furthermore, CO2 concentrations affect the susceptibility of both clinical and environmental C. neoformans isolates to the azole class of antifungal drugs, suggesting that antifungal testing in the presence of CO2 may improve the correlation between in vitro azole activity and patient outcome.IMPORTANCE A number of studies comparing either patient outcomes or model system virulence across large collections of Cryptococcus isolates have found significant heterogeneity in virulence even among strains with highly related genotypes. Because this heterogeneity cannot be explained by variations in the three well-characterized virulence traits (growth at host body temperature, melanization, and polysaccharide capsule formation), it has been widely proposed that additional C. neoformans virulence traits must exist. The natural niche of C. neoformans is in the environment, where the carbon dioxide concentration is very low (∼0.04%); in contrast, mammalian host tissue carbon dioxide concentrations are 125-fold higher (5%). We have found that the ability to grow in the presence of 5% carbon dioxide distinguishes low-virulence strains from high-virulence strains, even those with a similar genotype. Our findings suggest that carbon dioxide tolerance is a previously unrecognized virulence trait for C. neoformans.
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Polyene Macrolide Antibotic Derivatives: Preparation, Overcoming Drug Resistance, and Prospects for Use in Medical Practice (Review). Pharm Chem J 2019. [DOI: 10.1007/s11094-019-01922-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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18
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Santos-Gandelman J, Machado-Silva A. Drug development for cryptococcosis treatment: what can patents tell us? Mem Inst Oswaldo Cruz 2019; 114:e180391. [PMID: 30726342 PMCID: PMC6358010 DOI: 10.1590/0074-02760180391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/02/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Cryptococcosis is one of the most devastating fungal infections in humans. Despite the disease's clinical importance, current therapy is based on limited antifungals that are either toxic, inefficient, unavailable worldwide, or that quickly lead to resistance. OBJECTIVES The goal of this study was to provide insight into the future of cryptococcosis treatment by describing the patent scenario in this field. METHODS We identified and analysed patent documents revealing compounds with anti-cryptococcal activity supported by experimental evidence. FINDINGS Patenting in this field has been historically low, with an overall tendency of increase since 2012. Most applications are single filings, suggesting that they do not encompass strategic inventions requiring broad protection. Research and development essentially took place in China and the United States, which also represent the main countries of protection. Both academic and corporate institutions contributed to patenting in this field. Universities are the leading actors, with the highest patent family counts. CONCLUSION The low number of patents in this field indicates that efforts to mitigate the unmet needs for cryptococcosis treatment remain insufficient. Without investment to drive research and innovation, patients will likely continue to face inadequate assistance. Given the current scenario characterised by poor funding and low interest for technological development, drug repurposing may be the best alternative for cryptococcosis treatment.
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Affiliation(s)
- Juliana Santos-Gandelman
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Ciência e Tecnologia de Gestão da Inovação em Doenças Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Rio de Janeiro, RJ, Brasil
| | - Alice Machado-Silva
- Fundação Oswaldo Cruz-Fiocruz, Instituto Nacional de Ciência e Tecnologia de Gestão da Inovação em Doenças Negligenciadas, Centro de Desenvolvimento Tecnológico em Saúde, Rio de Janeiro, RJ, Brasil.,Fundação Oswaldo Cruz-Fiocruz, Instituto René Rachou, Belo Horizonte, MG, Brasil
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19
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Annunziato G, Giovati L, Angeli A, Pavone M, Del Prete S, Pieroni M, Capasso C, Bruno A, Conti S, Magliani W, Supuran CT, Costantino G. Discovering a new class of antifungal agents that selectively inhibits microbial carbonic anhydrases. J Enzyme Inhib Med Chem 2018; 33:1537-1544. [PMID: 30284487 PMCID: PMC6179086 DOI: 10.1080/14756366.2018.1516652] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Infections caused by pathogens resistant to the available antimicrobial treatments represent nowadays a threat to global public health. Recently, it has been demonstrated that carbonic anhydrases (CAs) are essential for the growth of many pathogens and their inhibition leads to growth defects. Principal drawbacks in using CA inhibitors (CAIs) as antimicrobial agents are the side effects due to the lack of selectivity toward human CA isoforms. Herein we report a new class of CAIs, which preferentially interacts with microbial CA active sites over the human ones. The mechanism of action of these inhibitors was investigated against an important fungal pathogen, Cryptococcus neoformans, revealing that they are also able to inhibit CA in microbial cells growing in vitro. At our best knowledge, this is the first report on newly designed synthetic compounds selectively targeting β-CAs and provides a proof of concept of microbial CAs suitability as an antimicrobial drug target.
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Affiliation(s)
| | - Laura Giovati
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Andrea Angeli
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
| | - Marialaura Pavone
- a Department of Food and Drugs , University of Parma , Parma , Italy
| | - Sonia Del Prete
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
| | - Marco Pieroni
- a Department of Food and Drugs , University of Parma , Parma , Italy
| | - Clemente Capasso
- d National Council of Research (CNR) , Istituto di Bioscenze e Biorisorse , Napoli , Italy
| | - Agostino Bruno
- a Department of Food and Drugs , University of Parma , Parma , Italy.,e Experimental Therapeutics Program , IFOM the FIRC Institute for Molecular Oncology Foundation , Milano , Italy
| | - Stefania Conti
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Walter Magliani
- b Department of Medicine and Surgery, Ospedale Maggiore di Parma , University of Parma , Parma , Italy
| | - Claudiu T Supuran
- c Department of NEUROFARBA, Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Firenze , Italy
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20
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Affiliation(s)
- Damian J Krysan
- a Department of Pediatrics and Microbiology/Immunology , University of Rochester School of Medicine and Dentistry , Rochester , NY , USA
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21
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Santos-Gandelman J, Rodrigues ML, Machado Silva A. Future perspectives for cryptococcosis treatment. Expert Opin Ther Pat 2018; 28:625-634. [PMID: 30084284 DOI: 10.1080/13543776.2018.1503252] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Cryptococcosis is one of the most devastating human fungal infections. Despite its impact, none of the standard antifungals were developed after 1990. New, improved, less toxic, affordable and widely available treatment is, therefore, imperative. AREAS COVERED This review offers an insight into technological developments for cryptococcosis disclosed in patent literature. From a broad search of patent documents claiming cryptococcosis treatment and having earliest priority between 1995 and 2015, we selected and summarized compounds/molecules (i) revealed in documents disclosing in vivo activity against Cryptococcus spp. or (ii) found in the pipeline of companies that appeared as assignees in our patent search. This information was complemented with data on compounds under development for this indication from the database Integrity (Clarivate Analytics). EXPERT OPINION This review demonstrates that drug development against cryptococcosis is discrete. However, it also shows that the existing development is not focused on a single class of molecules, but on different types of molecules with distinct fungal targets, reflecting the complexity of generating novel anti-cryptococcal tools. Given the intrinsic difficulties and high costs of drug development and the evident market failure in this field, we consider drug repurposing the most promising avenue for cryptococcosis treatment.
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Affiliation(s)
- Juliana Santos-Gandelman
- a Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças Negligenciadas (INCT-IDN), Centro de Desenvolvimento Tecnológico em Saúde (CDTS) , Fundação Oswaldo Cruz (Fiocruz) , Rio de Janeiro/RJ , Brazil
| | - Márcio Lourenço Rodrigues
- b Instituto Carlos Chagas (ICC) , Fundação Oswaldo Cruz - Fiocruz. Rua Prof , Algacyr Munhoz Mader, Curitiba/PR , Brazil.,c Instituto de Microbiologia Paulo de Góes , Universidade Federal do Rio de Janeiro - UFRJ , Av. Carlos Chagas Filho, Rio de Janeiro/RJ , Brazil
| | - Alice Machado Silva
- a Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças Negligenciadas (INCT-IDN), Centro de Desenvolvimento Tecnológico em Saúde (CDTS) , Fundação Oswaldo Cruz (Fiocruz) , Rio de Janeiro/RJ , Brazil.,d Instituto René Rachou , Fundação Oswaldo Cruz - Fiocruz Minas , Av. Augusto de Lima, Belo Horizonte , MG , Brazil
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22
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Montoya MC, DiDone L, Heier RF, Meyers MJ, Krysan DJ. Antifungal Phenothiazines: Optimization, Characterization of Mechanism, and Modulation of Neuroreceptor Activity. ACS Infect Dis 2018; 4:499-507. [PMID: 29058407 DOI: 10.1021/acsinfecdis.7b00157] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
New classes of antifungal drugs are an urgent unmet clinical need. One approach to the challenge of developing new antifungal drugs is to optimize the antifungal properties of currently used drugs with favorable pharmacologic properties, so-called drug or scaffold repurposing. New therapies for cryptococcal meningitis are particularly important given its worldwide burden of disease and limited therapeutic options. We report the first systematic structure-activity study of the anticryptococcal properties of the phenothiazines. We also show that the antifungal activity of the phenothiazine scaffold correlates well with its calmodulin antagonism properties and, thereby, provides the first insights into the mechanism of its antifungal properties. Guided by this mechanism, we have generated improved trifluoperazine derivatives with increased anticryptococcal activity and, importantly, reduced affinity for receptors that modulate undesired neurological effects. Taken together, these data suggest that phenothiazines represent a potentially useful scaffold for further optimization in the search for new antifungal drugs.
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Affiliation(s)
- Marhiah C. Montoya
- Clinical and Translational Science Institute, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Louis DiDone
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Richard F. Heier
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - Marvin J. Meyers
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 South Grand Blvd., St. Louis, Missouri 63104, United States
- Department of Chemistry, Saint Louis University, 1402 South Grand Blvd., St. Louis, Missouri 63104, United States
| | - Damian J. Krysan
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642, United States
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, New York 14642, United States
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23
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Molloy SF, Chiller T, Greene GS, Burry J, Govender NP, Kanyama C, Mfinanga S, Lesikari S, Mapoure YN, Kouanfack C, Sini V, Temfack E, Boulware DR, Dromer F, Denning DW, Day J, Stone NRH, Bicanic T, Jarvis JN, Lortholary O, Harrison TS, Jaffar S, Loyse A. Cryptococcal meningitis: A neglected NTD? PLoS Negl Trop Dis 2017; 11:e0005575. [PMID: 28662028 PMCID: PMC5490932 DOI: 10.1371/journal.pntd.0005575] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Síle F. Molloy
- Centre for Global Health, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
- * E-mail:
| | - Tom Chiller
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Gregory S. Greene
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jessica Burry
- Medecins Sans Frontières Access Campaign, Médecins Sans Frontières, Geneva, Switzerland
| | - Nelesh P. Govender
- National Institute for Communicable Diseases (Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses), Johannesburg, South Africa
- Division of Medical Microbiology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | - Sayoki Mfinanga
- National Institute of Medial Research, Muhimbili Medical Research Centre, Dar Es Salaam, Tanzania
| | - Sokoine Lesikari
- National Institute of Medial Research, Muhimbili Medical Research Centre, Dar Es Salaam, Tanzania
| | | | - Charles Kouanfack
- Department of Internal Medicine, Douala General Hospital, Douala, Cameroon
| | - Victor Sini
- Department of Internal Medicine, Douala General Hospital, Douala, Cameroon
| | | | - David R. Boulware
- Division of Infectious Disease and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Francoise Dromer
- Institut Pasteur, Molecular Mycology—CNRS URA3012, Department of Mycology, Paris, France
| | - David W. Denning
- Global Action Fund for Fungal Infections (GAFFI), Geneva, Switzerland
| | - Jeremy Day
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme Vietnam, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Neil R. H. Stone
- Centre for Global Health, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
| | - Tihana Bicanic
- Centre for Global Health, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
| | - Joseph N. Jarvis
- Department of Clinical Research, Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Botswana–University of Pennsylvania Partnership, Gaborone, Botswana
- Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Olivier Lortholary
- Institut Pasteur, Molecular Mycology—CNRS URA3012, Department of Mycology, Paris, France
| | - Thomas S. Harrison
- Centre for Global Health, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
| | - Shabbar Jaffar
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Angela Loyse
- Centre for Global Health, Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
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Lofgren S, Abassi M, Rhein J, Boulware DR. Recent advances in AIDS-related cryptococcal meningitis treatment with an emphasis on resource limited settings. Expert Rev Anti Infect Ther 2017; 15:331-340. [PMID: 28111998 PMCID: PMC5602588 DOI: 10.1080/14787210.2017.1285697] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
INTRODUCTION Recent advances in the treatment and prevention of cryptococcal meningitis have the potential to decrease AIDS-related deaths. Areas covered: Targeted screening for asymptomatic cryptococcal antigenemia in persons with AIDS is a cost effective method for reducing early mortality in patients on antiretroviral therapy. For persons with symptomatic cryptococcal meningitis, optimal initial management with amphotericin and flucytosine improves survival compared to alternative therapies; however, amphotsericin is difficult to administer and flucytosine has not been available in middle or low income countries, where cryptococcal meningitis is most prevalent. Expert commentary: Improved care for cryptococcal meningitis patients in resource-limited settings is possible, and new treatment possibilities are emerging.
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Affiliation(s)
- Sarah Lofgren
- a Division of Infectious Diseases & International Medicine, Department of Medicine , University of Minnesota , Minneapolis , MN , USA
- b Infectious Disease Institute, Makerere University , Kampala , Uganda
| | - Mahsa Abassi
- a Division of Infectious Diseases & International Medicine, Department of Medicine , University of Minnesota , Minneapolis , MN , USA
- b Infectious Disease Institute, Makerere University , Kampala , Uganda
| | - Joshua Rhein
- a Division of Infectious Diseases & International Medicine, Department of Medicine , University of Minnesota , Minneapolis , MN , USA
- b Infectious Disease Institute, Makerere University , Kampala , Uganda
| | - David R Boulware
- a Division of Infectious Diseases & International Medicine, Department of Medicine , University of Minnesota , Minneapolis , MN , USA
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25
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Joffe LS, Schneider R, Lopes W, Azevedo R, Staats CC, Kmetzsch L, Schrank A, Del Poeta M, Vainstein MH, Rodrigues ML. The Anti-helminthic Compound Mebendazole Has Multiple Antifungal Effects against Cryptococcus neoformans. Front Microbiol 2017; 8:535. [PMID: 28400768 PMCID: PMC5368277 DOI: 10.3389/fmicb.2017.00535] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 03/14/2017] [Indexed: 11/24/2022] Open
Abstract
Cryptococcus neoformans is the most lethal pathogen of the central nervous system. The gold standard treatment of cryptococcosis, a combination of amphotericin B with 5-fluorocytosine, involves broad toxicity, high costs, low efficacy, and limited worldwide availability. Although the need for new antifungals is clear, drug research and development (R&D) is costly and time-consuming. Thus, drug repurposing is an alternative to R&D and to the currently available tools for treating fungal diseases. Here we screened a collection of compounds approved for use in humans seeking for those with anti-cryptococcal activity. We found that benzimidazoles consist of a broad class of chemicals inhibiting C. neoformans growth. Mebendazole and fenbendazole were the most efficient antifungals showing in vitro fungicidal activity. Since previous studies showed that mebendazole reaches the brain in biologically active concentrations, this compound was selected for further studies. Mebendazole showed antifungal activity against phagocytized C. neoformans, affected cryptococcal biofilms profoundly and caused marked morphological alterations in C. neoformans, including reduction of capsular dimensions. Amphotericin B and mebendazole had additive anti-cryptococcal effects. Mebendazole was also active against the C. neoformans sibling species, C. gattii. To further characterize the effects of the drug a random C. gattii mutant library was screened and indicated that the antifungal activity of mebendazole requires previously unknown cryptococcal targets. Our results indicate that mebendazole is as a promising prototype for the future development of anti-cryptococcal drugs.
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Affiliation(s)
- Luna S Joffe
- Laboratório de Biologia Celular de Leveduras Patogênicas, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Rafael Schneider
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
| | - William Lopes
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
| | - Renata Azevedo
- Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde Rio de Janeiro, Brazil
| | - Charley C Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Lívia Kmetzsch
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Augusto Schrank
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Maurizio Del Poeta
- Veterans Administration Medical Center, NorthportNY, USA; Department of Molecular Genetics and Microbiology, Stony Brook University, Stony BrookNY, USA
| | - Marilene H Vainstein
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Marcio L Rodrigues
- Laboratório de Biologia Celular de Leveduras Patogênicas, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de JaneiroRio de Janeiro, Brazil; Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em SaúdeRio de Janeiro, Brazil
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26
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Rigi M, Khan K, Smith SV, Suleiman AO, Lee AG. Evaluation and management of the swollen optic disk in cryptococcal meningitis. Surv Ophthalmol 2017; 62:150-160. [DOI: 10.1016/j.survophthal.2016.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 10/02/2016] [Accepted: 10/10/2016] [Indexed: 12/20/2022]
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Chang YL, Yu SJ, Heitman J, Wellington M, Chen YL. New facets of antifungal therapy. Virulence 2017; 8:222-236. [PMID: 27820668 PMCID: PMC5354158 DOI: 10.1080/21505594.2016.1257457] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/19/2016] [Accepted: 11/01/2016] [Indexed: 01/13/2023] Open
Abstract
Invasive fungal infections remain a major cause of morbidity and mortality in immunocompromised patients, and such infections are a substantial burden to healthcare systems around the world. However, the clinically available armamentarium for invasive fungal diseases is limited to 3 main classes (i.e., polyenes, triazoles, and echinocandins), and each has defined limitations related to spectrum of activity, development of resistance, and toxicity. Further, current antifungal therapies are hampered by limited clinical efficacy, high rates of toxicity, and significant variability in pharmacokinetic properties. New antifungal agents, new formulations, and novel combination regimens may improve the care of patients in the future by providing improved strategies to combat challenges associated with currently available antifungal agents. Likewise, therapeutic drug monitoring may be helpful, but its present use remains controversial due to the lack of available data. This article discusses new facets of antifungal therapy with a focus on new antifungal formulations and the synergistic effects between drugs used in combination therapy.
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Affiliation(s)
- Ya-Lin Chang
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Shang-Jie Yu
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Melanie Wellington
- Department of Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Ying-Lien Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
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28
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Integrated Activity and Genetic Profiling of Secreted Peptidases in Cryptococcus neoformans Reveals an Aspartyl Peptidase Required for Low pH Survival and Virulence. PLoS Pathog 2016; 12:e1006051. [PMID: 27977806 PMCID: PMC5158083 DOI: 10.1371/journal.ppat.1006051] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/09/2016] [Indexed: 12/29/2022] Open
Abstract
The opportunistic fungal pathogen Cryptococcus neoformans is a major cause of mortality in immunocompromised individuals, resulting in more than 600,000 deaths per year. Many human fungal pathogens secrete peptidases that influence virulence, but in most cases the substrate specificity and regulation of these enzymes remains poorly understood. The paucity of such information is a roadblock to our understanding of the biological functions of peptidases and whether or not these enzymes are viable therapeutic targets. We report here an unbiased analysis of secreted peptidase activity and specificity in C. neoformans using a mass spectrometry-based substrate profiling strategy and subsequent functional investigations. Our initial studies revealed that global peptidase activity and specificity are dramatically altered by environmental conditions. To uncover the substrate preferences of individual enzymes and interrogate their biological functions, we constructed and profiled a ten-member gene deletion collection of candidate secreted peptidases. Through this deletion approach, we characterized the substrate specificity of three peptidases within the context of the C. neoformans secretome, including an enzyme known to be important for fungal entry into the brain. We selected a previously uncharacterized peptidase, which we term Major aspartyl peptidase 1 (May1), for detailed study due to its substantial contribution to extracellular proteolytic activity. Based on the preference of May1 for proteolysis between hydrophobic amino acids, we screened a focused library of aspartyl peptidase inhibitors and identified four high-affinity antagonists. Finally, we tested may1Δ strains in a mouse model of C. neoformans infection and found that strains lacking this enzyme are significantly attenuated for virulence. Our study reveals the secreted peptidase activity and specificity of an important human fungal pathogen, identifies responsible enzymes through genetic tests of their function, and demonstrates how this information can guide the development of high affinity small molecule inhibitors. Many pathogenic organisms secrete peptidases. The activity of these enzymes often contributes to virulence, making their study crucial for understanding host-pathogen biology and developing therapeutics. In this report, we employed an unbiased, activity-based profiling assay to examine the secreted peptidases of a fungal pathogen, Cryptococcus neoformans, which is responsible for 40% of AIDS-related deaths. We discovered which peptidases are secreted, identified their substrate specificity, and interrogated their biological functions. Through this analysis, we identified a principal enzyme responsible for the extracellular peptidase activity of C. neoformans, May1, and demonstrated its importance for growth in acidic environments. Characterization of its substrate preferences allowed us to identify compounds that are potent substrate-based inhibitors of May1 activity. Finally, we found that the presence of this enzyme promotes virulence in a mouse model of infection. Our comprehensive study reveals the expression, regulation and function of C. neoformans secreted peptidases, including evidence for the role of a novel aspartyl peptidase in virulence.
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The Celecoxib Derivative AR-12 Has Broad-Spectrum Antifungal Activity In Vitro and Improves the Activity of Fluconazole in a Murine Model of Cryptococcosis. Antimicrob Agents Chemother 2016; 60:7115-7127. [PMID: 27645246 DOI: 10.1128/aac.01061-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 09/04/2016] [Indexed: 12/24/2022] Open
Abstract
Only one new class of antifungal drugs has been introduced into clinical practice in the last 30 years, and thus the identification of small molecules with novel mechanisms of action is an important goal of current anti-infective research. Here, we describe the characterization of the spectrum of in vitro activity and in vivo activity of AR-12, a celecoxib derivative which has been tested in a phase I clinical trial as an anticancer agent. AR-12 inhibits fungal acetyl coenzyme A (acetyl-CoA) synthetase in vitro and is fungicidal at concentrations similar to those achieved in human plasma. AR-12 has a broad spectrum of activity, including activity against yeasts (e.g., Candida albicans, non-albicans Candida spp., Cryptococcus neoformans), molds (e.g., Fusarium, Mucor), and dimorphic fungi (Blastomyces, Histoplasma, and Coccidioides) with MICs of 2 to 4 μg/ml. AR-12 is also active against azole- and echinocandin-resistant Candida isolates, and subinhibitory AR-12 concentrations increase the susceptibility of fluconazole- and echinocandin-resistant Candida isolates. Finally, AR-12 also increases the activity of fluconazole in a murine model of cryptococcosis. Taken together, these data indicate that AR-12 represents a promising class of small molecules with broad-spectrum antifungal activity.
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Ianiri G, Boyce KJ, Idnurm A. Isolation of conditional mutations in genes essential for viability of Cryptococcus neoformans. Curr Genet 2016; 63:519-530. [PMID: 27783209 DOI: 10.1007/s00294-016-0659-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/02/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
Abstract
Discovering the genes underlying fundamental processes that enable cells to live and reproduce is a technical challenge, because loss of gene function in mutants results in organisms that cannot survive. This study describes a forward genetics method to identify essential genes in fungi, based on the propensity for Agrobacterium tumefaciens to insert T-DNA molecules into the promoters or 5' untranslated regions of genes and by placing a conditional promoter within the T-DNA. Insertions of the promoter of the GAL7 gene were made in the human pathogen Cryptococcus neoformans. Nine strains of 960 T-DNA insertional mutants screened grew on media containing galactose, but had impaired growth on media containing glucose, which suppresses expression from GAL7. T-DNA insertions were found in the homologs of IDI1, MRPL37, NOC3, NOP56, PRE3 and RPL17, all of which are essential in ascomycete yeasts Saccharomyces cerevisiae or Schizosaccharomyces pombe. Altering the carbon source in the medium provided a system to identify phenotypes in response to stress agents. The pre3 proteasome subunit mutant was further characterized. The T-DNA insertion and phenotype co-segregate in progeny from a cross, and the growth defect is complemented by the reintroduction of the wild type gene into the insertional mutant. A deletion allele was generated in a diploid strain, this heterozygous strain was sporulated, and analysis of the progeny provided additional genetic evidence that PRE3 is essential. The experimental design is applicable to other fungi and has other forward genetic applications such as to isolate over-expression suppressors or enhance the production of traits of interest.
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Affiliation(s)
- Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA.,Dipartimento di Agricoltura, Ambiente e Alimenti, Università degli Studi del Molise, Via F. De Sanctis Snc, 86100, Campobasso, Italy
| | - Kylie J Boyce
- School of BioSciences, BioSciences 2, University of Melbourne, Building 122, Melbourne, VIC, 3010, Australia
| | - Alexander Idnurm
- School of BioSciences, BioSciences 2, University of Melbourne, Building 122, Melbourne, VIC, 3010, Australia.
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Samantaray S, Correia JN, Garelnabi M, Voelz K, May RC, Hall RA. Novel cell-based in vitro screen to identify small-molecule inhibitors against intracellular replication of Cryptococcus neoformans in macrophages. Int J Antimicrob Agents 2016; 48:69-77. [PMID: 27289450 PMCID: PMC4942879 DOI: 10.1016/j.ijantimicag.2016.04.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/07/2016] [Accepted: 04/16/2016] [Indexed: 01/08/2023]
Abstract
The fungal pathogen Cryptococcus neoformans poses a major threat to immunocompromised patients and is a leading killer of human immunodeficiency virus (HIV)-infected patients worldwide. Cryptococci are known to manipulate host macrophages and can either remain latent or proliferate intracellularly within the host phagocyte, a favourable niche that also renders them relatively insensitive to antifungal agents. Here we report an attempt to address this limitation by using a fluorescence-based drug screening method to identify potential inhibitors of intracellular proliferation of C. neoformans. The Prestwick Chemical Library(®) of FDA-approved small molecules was screened for compounds that limit the intracellular replication of a fluorescently-tagged C. neoformans reference strain (H99-GFP) in macrophages. Preliminary screening revealed 19 of 1200 compounds that could significantly reduce intracellular growth of the pathogen. Secondary screening and host cell cytotoxicity assays highlighted fendiline hydrochloride as a potential drug candidate for the development of future anticryptococcal therapies. Live cell imaging demonstrated that this Ca(2+) channel blocker strongly enhanced phagosome maturation in macrophages leading to improved fungal killing and reduced intracellular replication. Whilst the relatively high dose of fendiline hydrochloride required renders it unfit for clinical deployment against cryptococcosis, this study highlights a novel approach for identifying new lead compounds and unravels a pharmacologically promising scaffold towards the development of novel antifungal therapies for this neglected disease.
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Affiliation(s)
- Sweta Samantaray
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Joao N Correia
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Mariam Garelnabi
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Kerstin Voelz
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Robin C May
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
| | - Rebecca A Hall
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
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Induction of Protective Immunity to Cryptococcal Infection in Mice by a Heat-Killed, Chitosan-Deficient Strain of Cryptococcus neoformans. mBio 2016; 7:mBio.00547-16. [PMID: 27165801 PMCID: PMC4959652 DOI: 10.1128/mbio.00547-16] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cryptococcus neoformans is a major opportunistic fungal pathogen that causes fatal meningoencephalitis in immunocompromised individuals and is responsible for a large proportion of AIDS-related deaths. The fungal cell wall is an essential organelle which undergoes constant modification during various stages of growth and is critical for fungal pathogenesis. One critical component of the fungal cell wall is chitin, which in C. neoformans is predominantly deacetylated to chitosan. We previously reported that three chitin deacetylase (CDA) genes have to be deleted to generate a chitosan-deficient C. neoformans strain. This cda1Δ2Δ3Δ strain was avirulent in mice, as it was rapidly cleared from the lungs of infected mice. Here, we report that clearance of the cda1Δ2Δ3Δ strain was associated with sharply spiked concentrations of proinflammatory molecules that are known to be critical mediators of the orchestration of a protective Th1-type adaptive immune response. This was followed by the selective enrichment of the Th1-type T cell population in the cda1Δ2Δ3Δ strain-infected mouse lung. Importantly, this response resulted in the development of robust protective immunity to a subsequent lethal challenge with a virulent wild-type C. neoformans strain. Moreover, protective immunity was also induced in mice vaccinated with heat-killed cda1Δ2Δ3Δ cells and was effective in multiple mouse strains. The results presented here provide a strong framework to develop the cda1Δ2Δ3Δ strain as a potential vaccine candidate for C. neoformans infection. The most commonly used anticryptococcal therapies include amphotericin B, 5-fluorocytosine, and fluconazole alone or in combination. Major drawbacks of these treatment options are their limited efficacy, poor availability in limited resource areas, and potential toxicity. The development of antifungal vaccines and immune-based therapeutic interventions is promising and an attractive alternative to chemotherapeutics. Currently, there are no fungal vaccines in clinical use. This is the first report of a C. neoformans deletion strain with an avirulent phenotype in mice exhibiting protective immunity when used as a vaccine after heat inactivation, although other strains that overexpress fungal or murine proteins have recently been shown to induce a protective response. The data presented here demonstrate the potential for developing the avirulent cda1Δ2Δ3Δ strain into a vaccine-based therapy to treat C. neoformans infection.
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Cullen PJ, Edgerton M. Unmasking fungal pathogens by studying MAPK-dependent cell wall regulation in Candida albicans. Virulence 2016; 7:502-5. [PMID: 27088569 DOI: 10.1080/21505594.2016.1177695] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Paul J Cullen
- a Department of Biological Sciences , State University of New York at Buffalo , Buffalo , NY , USA
| | - Mira Edgerton
- b Department of Oral Biology , State University of New York at Buffalo , Buffalo , NY , USA
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Rodrigues ML. Funding and Innovation in Diseases of Neglected Populations: The Paradox of Cryptococcal Meningitis. PLoS Negl Trop Dis 2016; 10:e0004429. [PMID: 26964103 PMCID: PMC4786104 DOI: 10.1371/journal.pntd.0004429] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Marcio L. Rodrigues
- Fundação Oswaldo Cruz (Fiocruz), Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- * E-mail:
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Abassi M, Boulware DR, Rhein J. Cryptococcal Meningitis: Diagnosis and Management Update. CURRENT TROPICAL MEDICINE REPORTS 2015; 2:90-99. [PMID: 26279970 PMCID: PMC4535722 DOI: 10.1007/s40475-015-0046-y] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Recent advances in the diagnosis and management of cryptococcal meningitis are promising and have been improving long-term survival. Point of care testing has made diagnosing cryptococcal meningitis rapid, practical, and affordable. Targeted screening and treatment programs for cryptococcal antigenemia are a cost effective method for reducing early mortality on antiretroviral therapy (ART). Optimal initial management with amphotericin and flucytosine improves survival against alternative therapies, although amphotericin is difficult to administer and flucytosine is not available in middle or low income countries, where cryptococcal meningitis is most prevalent. Controlling increased intracranial pressure with serial therapeutic lumbar punctures has a proven survival benefit. Delaying ART initiation for 4 weeks after the diagnosis of cryptococcal meningitis is associated with improved survival. Fortunately, new approaches have been leading the way toward improving care for cryptococcal meningitis patients. New trials utilizing different combinations of antifungal therapy are reviewed, and we summarize the efficacy of different regimens.
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Affiliation(s)
- Mahsa Abassi
- University of Minnesota, Minneapolis, MN, USA
- Infectious Disease Institute, Makerere University, Kampala, Uganda
| | | | - Joshua Rhein
- University of Minnesota, Minneapolis, MN, USA
- Infectious Disease Institute, Makerere University, Kampala, Uganda
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Structure-activity relationships for the antifungal activity of selective estrogen receptor antagonists related to tamoxifen. PLoS One 2015; 10:e0125927. [PMID: 26016941 PMCID: PMC4446328 DOI: 10.1371/journal.pone.0125927] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/26/2015] [Indexed: 11/25/2022] Open
Abstract
Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM) tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of structurally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular characteristics affecting anti-cryptococcal activity emerged from our studies: 1) the presence of an alkylamino group tethered to one of the aromatic rings of the triphenylethylene core; 2) an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3) electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimization of this promising anti-cryptococcal scaffold.
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Idnurm A, Lin X. Rising to the challenge of multiple Cryptococcus species and the diseases they cause. Fungal Genet Biol 2015; 78:1-6. [PMID: 25983191 DOI: 10.1016/j.fgb.2015.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/05/2015] [Accepted: 05/06/2015] [Indexed: 12/28/2022]
Abstract
Cryptococcus neoformans and Cryptococcus gattii are well-studied basidiomyceteous yeasts that are capable of causing disease in healthy and immunocompromised people. The Conference on Cryptococcus and Cryptococcosis (ICCC) is held every three years: the accompanying Special Issue stems from the 9th ICCC and covers a subset of the topics related to these fungi in detail. This conference started with a revised and reduced estimate of disease burden globally, in part due to improved treatment for HIV(+) people. However, mortality from cryptococcosis remains consistently high for those unfortunate to have limited access to therapies or without underlying immunodeficiencies. As such, there are yet still great distances to be covered to address antifungal drug availability, the need for new antifungal agents and the timing and doses of these agents in conjunction with antiviral therapy, underscoring the importance of continued research. A notable point from the 9th ICCC was the research addressing the variation in the pathogen and host populations. Analysis of cryptococcal strain variability, particularly at the molecular level, has resolved distinct lineages with the consequence of a taxonomic revision that divides C. neoformans and C. gattii into seven Cryptococcus species. Similarly, analysis of host factors in so called "immune-competent" individuals revealed previously unrecognized risk factors. Research on these species has established them as important model organisms to understand gene evolution and function in other fungi and eukaryotes. The stage is set for the refinement of research directions, leading ultimately to better treatment of this monophyletic clade of pathogens in the genus Cryptococcus.
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Affiliation(s)
- Alexander Idnurm
- School of BioSciences, University of Melbourne, VIC 3010, Australia.
| | - Xiaorong Lin
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.
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