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Sonnberger J, Kasper L, Lange T, Brunke S, Hube B. "We've got to get out"-Strategies of human pathogenic fungi to escape from phagocytes. Mol Microbiol 2024; 121:341-358. [PMID: 37800630 DOI: 10.1111/mmi.15149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023]
Abstract
Human fungal pathogens are a deadly and underappreciated risk to global health that most severely affect immunocompromised individuals. A virulence attribute shared by some of the most clinically relevant fungal species is their ability to survive inside macrophages and escape from these immune cells. In this review, we discuss the mechanisms behind intracellular survival and elaborate how escape is mediated by lytic and non-lytic pathways as well as strategies to induce programmed host cell death. We also discuss persistence as an alternative to rapid host cell exit. In the end, we address the consequences of fungal escape for the host immune response and provide future perspectives for research and development of targeted therapies.
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Affiliation(s)
- Johannes Sonnberger
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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2
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Alselami A, Drummond RA. How metals fuel fungal virulence, yet promote anti-fungal immunity. Dis Model Mech 2023; 16:dmm050393. [PMID: 37905492 PMCID: PMC10629672 DOI: 10.1242/dmm.050393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023] Open
Abstract
Invasive fungal infections represent a significant global health problem, and present several clinical challenges, including limited treatment options, increasing rates of antifungal drug resistance and compounding comorbidities in affected patients. Metals, such as copper, iron and zinc, are critical for various biological and cellular processes across phyla. In mammals, these metals are important determinants of immune responses, but pathogenic microbes, including fungi, also require access to these metals to fuel their own growth and drive expression of major virulence traits. Therefore, host immune cells have developed strategies to either restrict access to metals to induce starvation of invading pathogens or deploy toxic concentrations within phagosomes to cause metal poisoning. In this Review, we describe the mechanisms regulating fungal scavenging and detoxification of copper, iron and zinc and the importance of these mechanisms for virulence and infection. We also outline how these metals are involved in host immune responses and the consequences of metal deficiencies or overloads on how the host controls invasive fungal infections.
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Affiliation(s)
- Alanoud Alselami
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Rebecca A. Drummond
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
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Rasouli Koohi S, Shankarnarayan SA, Galon CM, Charlebois DA. Identification and Elimination of Antifungal Tolerance in Candida auris. Biomedicines 2023; 11:biomedicines11030898. [PMID: 36979876 PMCID: PMC10045952 DOI: 10.3390/biomedicines11030898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/17/2023] Open
Abstract
Antimicrobial resistance is a global health crisis to which pathogenic fungi make a substantial contribution. The human fungal pathogen C. auris is of particular concern due to its rapid spread across the world and its evolution of multidrug resistance. Fluconazole failure in C. auris has been recently attributed to antifungal “tolerance”. Tolerance is a phenomenon whereby a slow-growing subpopulation of tolerant cells, which are genetically identical to susceptible cells, emerges during drug treatment. We use microbroth dilution and disk diffusion assays, together with image analysis, to investigate antifungal tolerance in C. auris to all three classes of antifungal drugs used to treat invasive candidiasis. We find that (1) C. auris is tolerant to several common fungistatic and fungicidal drugs, which in some cases can be detected after 24 h, as well as after 48 h, of antifungal drug exposure; (2) the tolerant phenotype reverts to the susceptible phenotype in C. auris; and (3) combining azole, polyene, and echinocandin antifungal drugs with the adjuvant chloroquine in some cases reduces or eliminates tolerance and resistance in patient-derived C. auris isolates. These results suggest that tolerance contributes to treatment failure in C. auris infections for a broad range of antifungal drugs, and that antifungal adjuvants may improve treatment outcomes for patients infected with antifungal-tolerant or antifungal-resistant fungal pathogens.
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Affiliation(s)
| | | | | | - Daniel A. Charlebois
- Department of Physics, University of Alberta, Edmonton, AB T6G 2R3, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- Correspondence:
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Madu UL, Ogundeji AO, Pohl CH, Albertyn J, Sebolai OM. Primaquine, an antimalarial drug that controls the growth of cryptococcal cells. J Mycol Med 2023; 33:101361. [PMID: 36812704 DOI: 10.1016/j.mycmed.2023.101361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 02/08/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023]
Abstract
INTRODUCTION The treatment of Cryptococcus neoformans with fluconazole and amphotericin B is, at times, characterised by clinical failure. Therefore, this study sought to re-purpose primaquine (PQ) as an anti-Cryptococcus compound. METHOD The susceptibility profile of some cryptococcal strains towards PQ was determined using EUCAST guidelines, and PQ's mode of action was examined. In the end, the ability of PQ to enhance in vitro macrophage phagocytosis was also assessed. RESULTS We show that PQ had a significant inhibitory effect on the metabolic activity of all tested cryptococcal strains, with 60 µM, defined as MIC50 in this preliminary study, as it reduced the metabolic activity by more than 50%. Moreover, at this concentration, the drug was able to affect mitochondrial function adversely, as treated cells displayed significant (p < 0.05) loss of mitochondrial membrane potential, cytochrome c (cyt c) leakage and overproduction of reactive oxygen species (ROS) when compared to non-treated cells. It is our reasoned summation that the produced ROS targeted the cell walls and cell membranes, inducing observable ultrastructural changes and a significant (p < 0.05) increase in membrane permeability when compared to non-treated cells. Concerning the PQ effect on macrophages, it was noted that it significantly (p < 0.05) enhanced macrophage phagocytic efficiency compared to non-treated macrophages. CONCLUSION This preliminary study highlights the potential of PQ to inhibit the in vitro growth of cryptococcal cells. Moreover, PQ could control the proliferation of cryptococcal cells inside macrophages, which they often manipulate in a Trojan horse-like manner.
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Affiliation(s)
- Uju L Madu
- Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein, 9301, South Africa
| | - Adepemi O Ogundeji
- Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein, 9301, South Africa
| | - Carolina H Pohl
- Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein, 9301, South Africa
| | - Jacobus Albertyn
- Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein, 9301, South Africa
| | - Olihile M Sebolai
- Department of Microbiology and Biochemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein, 9301, South Africa.
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5
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Wang X, Long X, Jia S, Zhu J, Zhou Z, Ahmed S, Jiang Y, Jiang Y. In vitro and in vivo synergistic effects of hydroxychloroquine and itraconazole on Cryptococcus neoformans. Folia Microbiol (Praha) 2023:10.1007/s12223-023-01040-4. [PMID: 36753031 DOI: 10.1007/s12223-023-01040-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 01/26/2023] [Indexed: 02/09/2023]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that can cause life-threatening invasive fungal infections. As its prevalence and drug resistance continue to rise, cryptococcosis requires new treatment options. Tapping into the potential antifungal effects of traditional drugs or combination therapy has become one of the options. This study was the first to examine the interaction of hydroxychloroquine (HCQ) and itraconazole (ITR) on Cryptococcus neoformans in vitro and in vivo. Our results showed that HCQ alone and in combination with ITR exhibited antifungal activity against C. neoformans planktonic cells. When HCQ was combined with ITR, the minimal inhibitory concentration (MIC) value of HCQ decreased to 32 μg/mL, and the MIC value of ITR decreased from 0.25 μg/mL to 0.06-0.25 μg/mL. The time-killing curve showed that the combined application of HCQ and ITR significantly shortened the killing time, dynamically defining the antifungal activity. The minimum biofilm clearance concentration (MBEC) of HCQ was only 32 μg/mL, which was significantly lower than the MIC of HCQ for planktonic cells. When combined with ITR, the MBEC of ITR decreased from 128 μg/mL to 2-1 μg/mL, and the MBEC of HCQ decreased from 32 μg/mL to 4 μg/mL, indicating a synergistic antifungal biofilm effect. In comparison to ITR alone, the combination of HCQ and ITR treatment increased the survival of C. neoformans-infected Galleria mellonella larvae and decreased the fungal burden of infected larvae. Mechanistic investigations revealed that HCQ might damage C. neoformans cell membranes, impact the structure of fungal cells, cause extracellular material leakage, and have a potent affinity for attaching to the C. neoformans genomic DNA. In conclusion, HCQ has potential clinical application in the treatment of cryptococcosis.
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Affiliation(s)
- Xue Wang
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China.,Department of Microbiology, Basic Medical School, Guizhou Medical University, Guiyang, China
| | - Xuemei Long
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Songgan Jia
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Jiali Zhu
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Zhan Zhou
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Sarah Ahmed
- Centre of Expertise in Mycology of Radboud University Medical Center/Canisius Wilhelmina Hospital, Nijmegen, Netherlands
| | - Yinhui Jiang
- Laboratory of Medical Molecular Biology, Guizhou Medical University, Guiyang, China
| | - Yanping Jiang
- Department of Dermatology, The Affiliated Hospital of Guizhou Medical University, Guiyang, China. .,Centre of Expertise in Mycology of Radboud University Medical Center/Canisius Wilhelmina Hospital, Nijmegen, Netherlands.
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6
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Valdez AF, Miranda DZ, Guimarães AJ, Nimrichter L, Nosanchuk JD. Pathogenicity & Virulence of Histoplasma capsulatum - a multifaceted organism adapted to intracellular environments. Virulence 2022; 13:1900-1919. [PMID: 36266777 DOI: 10.1080/21505594.2022.2137987] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsulatum. Although healthy individuals can develop histoplasmosis, the disease is particularly life-threatening in immunocompromised patients, with a wide range of clinical manifestations depending on the inoculum and virulence of the infecting strain. In this review, we discuss the established virulence factors and pathogenesis traits that make H. capsulatum highly adapted to a wide variety of hosts, including mammals. Understanding and integrating these mechanisms is a key step towards devising new preventative and therapeutic interventions.
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Affiliation(s)
- Alessandro F Valdez
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Geral, Rio de Janeiro, Brazil
| | - Daniel Zamith Miranda
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Allan Jefferson Guimarães
- Universidade Federal Fluminense, Instituto Biomédico, Departamento de Microbiologia e Parasitologia - MIP, Niterói, Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Geral, Rio de Janeiro, Brazil
| | - Joshua D Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
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Mjokane N, Folorunso OS, Ogundeji AO, Sebolai OM. The Possible Role of Microbial Proteases in Facilitating SARS-CoV-2 Brain Invasion. Biology (Basel) 2021; 10:966. [PMID: 34681064 DOI: 10.3390/biology10100966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 01/15/2023]
Abstract
SARS-CoV-2 has been shown to display proclivity towards organs bearing angiotensin-converting enzyme (ACE2) expression cells. Of interest herein is the ability of the virus to exhibit neurotropism. However, there is limited information on how this virus invades the brain. With this contribution, we explore how, in the context of a microbial co-infection using a cryptococcal co-infection as a model, SARS-CoV-2 could reach the brain. We theorise that the secretion of proteases by disseminated fungal cells might also activate the S2 domain of the viral spike glycoprotein for membrane fusion with brain endothelial cells leading to endocytosis. Understanding this potential invasion mechanism could lead to better SARS-CoV-2 intervention measures, which may also be applicable in instances of co-infection, especially with protease-secreting pathogens.
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Rossi DC, Figueroa JAL, Buesing WR, Candor K, Blancett LT, Evans HM, Lenchitz R, Crowther BL, Elsegeiny W, Williamson PR, Rupp J, Deepe GS. A metabolic inhibitor arms macrophages to kill intracellular fungal pathogens by manipulating zinc homeostasis. J Clin Invest 2021; 131:e147268. [PMID: 34237029 DOI: 10.1172/jci147268] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 07/06/2021] [Indexed: 01/01/2023] Open
Abstract
Macrophages deploy numerous strategies to combat invasion by microbes. One tactic is to restrict acquisition of diverse nutrients, including trace metals, a process termed nutritional immunity. Intracellular pathogens adapt to a resource-poor environment by marshaling mechanisms to harvest nutrients. Carbon acquisition is crucial for pathogen survival; compounds that reduce availability are a potential strategy to control intracellular replication. Treatment of macrophages with the glucose analog 2-deoxy-D-glucose (2-DG) armed phagocytes to eliminate the intracellular fungal pathogen Histoplasma capsulatum in vitro and in vivo. Killing did not rely on altering access to carbon-containing molecules or changes in ATP, ER stress, or autophagy. Unexpectedly, 2-DG undermined import of exogenous zinc into macrophages, decreasing the quantity of cytosolic and phagosomal zinc. The fungus perished as a result of zinc starvation. This change in metal ingress was not ascribed to a defect in a single importer; rather, there was a collective impairment in transporter activity. This effect promoted the antifungal machinery of macrophages and expanded the complexity of 2-DG activities far beyond manipulating glycolysis. Mechanistic metabolic studies employing 2-DG will have to consider its effect on zinc transport. Our preclinical data support consideration of this agent as a possible adjunctive therapy for histoplasmosis.
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Affiliation(s)
- Diego Cp Rossi
- Division of Infectious Diseases, College of Medicine and
| | - Julio A Landero Figueroa
- University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA
| | | | - Kathleen Candor
- Division of Infectious Diseases, College of Medicine and.,University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA.,Immunology Graduate Program and
| | | | | | - Rena Lenchitz
- Division of Infectious Diseases, College of Medicine and
| | - Bradford L Crowther
- Division of Infectious Diseases, College of Medicine and.,Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Waleed Elsegeiny
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Peter R Williamson
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), NIH, Bethesda, Maryland, USA
| | - Jan Rupp
- Department of Infectious Diseases and Microbiology, German Center for Infection Research, Hamburg-Lübeck-Borstel-Riems, Lübeck, Germany
| | - George S Deepe
- Division of Infectious Diseases, College of Medicine and
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Shen Q, Rappleye CA. Living Within the Macrophage: Dimorphic Fungal Pathogen Intracellular Metabolism. Front Cell Infect Microbiol 2020; 10:592259. [PMID: 33178634 PMCID: PMC7596272 DOI: 10.3389/fcimb.2020.592259] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
Histoplasma and Paracoccidioides are related thermally dimorphic fungal pathogens that cause deadly mycoses (i.e., histoplasmosis and paracoccidioidomycosis, respectively) primarily in North, Central, and South America. Mammalian infection results from inhalation of conidia and their subsequent conversion into pathogenic yeasts. Macrophages in the lung are the first line of defense, but are generally unable to clear these fungi. Instead, Histoplasma and Paracoccidioides yeasts survive and proliferate within the phagosomal compartment of host macrophages. Growth within macrophages requires strategies for acquisition of sufficient nutrients (e.g., carbon, nitrogen, and essential trace elements and co-factors) from the nutrient-depleted phagosomal environment. We review the transcriptomic and recent functional genetic studies that are defining how these intracellular fungal pathogens tune their metabolism to the resources available in the macrophage phagosome. In addition, recent studies have shown that the nutritional state of the macrophage phagosome is not static, but changes upon activation of adaptive immune responses. Understanding the metabolic requirements of these dimorphic pathogens as they thrive within host cells can provide novel targets for therapeutic intervention.
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Affiliation(s)
- Qian Shen
- Department of Biology, Rhodes College, Memphis, TN, United States
| | - Chad A Rappleye
- Department of Microbiology, Ohio State University, Columbus, OH, United States
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Tripathy S, Dassarma B, Roy S, Chabalala H, Matsabisa MG. A review on possible modes of action of chloroquine/hydroxychloroquine: repurposing against SAR-CoV-2 (COVID-19) pandemic. Int J Antimicrob Agents 2020; 56:106028. [PMID: 32450198 PMCID: PMC7243790 DOI: 10.1016/j.ijantimicag.2020.106028] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/17/2020] [Indexed: 12/12/2022]
Abstract
Chloroquine (CQ) has diverse modes of action against viral infections. CQ may interfere with SARS-CoV-2 attachment to the host ACE2 receptor. CQ may hamper the STING pathway to attenuate the pro-inflammatory response. Hydroxychloroquine (HCQ) might be a logical approach in the treatment of SARS-CoV-2 infection. Large clinical trials are needed before clinical recommendations of HCQ against COVID-19.
Chloroquine (CQ) and its analogue hydroxychloroquine (HCQ) have long been used worldwide as frontline drugs for the treatment and prophylaxis of human malaria. Since the first reported cases in Wuhan, China, in late December 2019, humans have been under threat from coronavirus disease 2019 (COVID-19) caused by the novel coronavirus SARS-CoV-2 (previously known as 2019-nCoV), subsequently declared a pandemic. While the world is searching for expedited approval for a vaccine, which may be only preventative and not a cure, physicians and country leaders are considering several concerted clinical trials suggesting that the age-old antimalarial drugs CQ/HCQ could be a potent therapeutic against COVID-19. Based on accumulating scientific reports, here we highlight the possible modes of action of CQ/HCQ that could justify its use against viral infections. Considering the global health crisis of the COVID-19 pandemic, the option of repurposing old drugs, e.g. CQ/HCQ, particularly HCQ, for the treatment of SARS-CoV-2 infection could be a good choice. CQ/HCQ has diverse modes of action, including alteration of the acidic environment inside lysosomes and late endosomes, preventing endocytosis, exosome release and phagolysosomal fusion, and inhibition of the host cytokine storm. One or more diverse mechanisms might work against viral infections and reduce mortality. As there is no cure for COVID-19, clinical testing of HCQ is urgently required to determine its potency against SARS-CoV-2, as this is the currently available treatment option. There remains a need to find other innovative drug candidates as possible candidates to enter clinical evaluation and testing.
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Affiliation(s)
- Satyajit Tripathy
- Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa
| | - Barsha Dassarma
- Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa
| | - Somenath Roy
- Ex-Professor, Department of Human Physiology with Community Health, Vidyasagar University, Paschim Medinipur 721102, India
| | - Hlupheka Chabalala
- IK-based Technology Innovations, Department of Science and Innovations, Brummeria, Pretoria 0001, South Africa
| | - Motlalepula Gilbert Matsabisa
- Department of Pharmacology, School of Medicine, Faculty of Health Sciences, University of the Free State, Bloemfontein 9300, South Africa.
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Riedelberger M, Penninger P, Tscherner M, Seifert M, Jenull S, Brunnhofer C, Scheidl B, Tsymala I, Bourgeois C, Petryshyn A, Glaser W, Limbeck A, Strobl B, Weiss G, Kuchler K. Type I Interferon Response Dysregulates Host Iron Homeostasis and Enhances Candida glabrata Infection. Cell Host Microbe 2020; 27:454-466.e8. [PMID: 32075740 DOI: 10.1016/j.chom.2020.01.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/26/2019] [Accepted: 01/28/2020] [Indexed: 12/23/2022]
Abstract
Type I interferons (IFNs-I) fulfil multiple protective functions during pathogenic infections, but they can also cause detrimental effects and enhance immunopathology. Here, we report that IFNs-I promote the dysregulation of iron homeostasis in macrophages during systemic infections with the intracellular pathogen Candida glabrata, leading to fungal survival and persistence. By engaging JAK1, IFNs-I disturb the balance of the transcriptional activator NRF2 and repressor BACH1 to induce downregulation of the key iron exporter Fpn1 in macrophages. This leads to enhanced iron accumulation in the phagolysosome and failure to restrict fungal access to iron pools. As a result, C. glabrata acquires iron via the Sit1/Ftr1 iron transporter system, facilitating fungal intracellular replication and immune evasion. Thus, IFNs-I are central regulators of iron homeostasis, which can impact infection, and restricting iron bioavailability may offer therapeutic strategies to combat invasive fungal infections.
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12
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Friedrich D, Zapf D, Lohse B, Fecher RA, Deepe GS Jr, Rupp J. The HIF-1α/LC3-II Axis Impacts Fungal Immunity in Human Macrophages. Infect Immun 2019; 87:e00125-19. [PMID: 31036602 DOI: 10.1128/IAI.00125-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/16/2019] [Indexed: 01/03/2023] Open
Abstract
The fungal pathogen Histoplasma capsulatum causes a spectrum of disease, ranging from local pulmonary infection to disseminated disease. The organism seeks residence in macrophages, which are permissive for its survival. Hypoxia-inducible factor 1α (HIF-1α), a principal regulator of innate immunity to pathogens, is necessary for macrophage-mediated immunity to H. capsulatum in mice. In the present study, we analyzed the effect of HIF-1α in human macrophages infected with this fungus. HIF-1α stabilization was detected in peripheral blood monocyte-derived macrophages at 2 to 24 h after infection with viable yeast cells. Further, host mitochondrial respiration and glycolysis were enhanced. In contrast, heat-killed yeasts induced early, but not later, stabilization of HIF-1α. Since the absence of HIF-1α is detrimental to host control of infection, we asked if large amounts of HIF-1α protein, exceeding those induced by H. capsulatum, altered macrophage responses to this pathogen. Exposure of infected macrophages to an HIF-1α stabilizer significantly reduced recovery of H. capsulatum from macrophages and produced a decrement in mitochondrial respiration and glycolysis compared to those of controls. We observed recruitment of the autophagy-related protein LC3-II to the phagosome, whereas enhancing HIF-1α reduced phagosomal decoration. This finding suggested that H. capsulatum exploited an autophagic process to survive. In support of this assertion, inhibition of autophagy activated macrophages to limit intracellular growth of H. capsulatum Thus, enhancement of HIF-1α creates a hostile environment for yeast cells in human macrophages by interrupting the ability of the pathogen to provoke host cell autophagy.
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Brechting PJ, Rappleye CA. Histoplasma Responses to Nutritional Immunity Imposed by Macrophage Activation. J Fungi (Basel) 2019; 5. [PMID: 31195617 DOI: 10.3390/jof5020045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 05/31/2019] [Accepted: 05/31/2019] [Indexed: 01/25/2023] Open
Abstract
The fungal pathogen Histoplasma capsulatum resides within the phagosome of host phagocytic cells. Within this intracellular compartment, Histoplasma yeast replication requires the acquisition of several essential nutrients, including metal ions. Recent work has shown that while iron, zinc, and copper are sufficiently abundant in resting macrophages, cytokine activation of these host cells causes restriction of these metals from intracellular yeasts as a form of nutritional immunity. Faced with limited iron availability in the phagosome following macrophage activation by IFN-γ, Histoplasma yeasts secrete iron-scavenging siderophores and employ multiple strategies for reduction of ferric iron to the more physiologically useful ferrous form. IFN-γ activation of macrophages also limits availability of copper in the phagosome, forcing Histoplasma reliance on the high affinity Ctr3 copper importer for copper acquisition. GM-CSF activation stimulates macrophage production of zinc-chelating metallothioneins and zinc transporters to sequester zinc from Histoplasma yeasts. In response, Histoplasma yeasts express the Zrt2 zinc importer. These findings highlight the dynamics of phagosomal metal ion concentrations in host-pathogen interactions and explain one mechanism by which macrophages become a less permissive environment for Histoplasma replication with the onset of adaptive immunity.
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Clark HR, Powell AB, Simmons KA, Ayubi T, Kale SD. Endocytic Markers Associated with the Internalization and Processing of Aspergillus fumigatus Conidia by BEAS-2B Cells. mSphere 2019; 4:e00663-18. [PMID: 30728282 DOI: 10.1128/mSphere.00663-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Conidia from the fungus Aspergillus fumigatus are notorious for their ability to stay airborne. This characteristic is believed to allow conidia to penetrate into the cleanest environments. Several hundred conidia are thought to be inhaled each day by a given individual and then expelled by mucociliary clearance. Given that airway epithelial cells make up a significant portion of the pulmonary-air interface, we set out to determine the percentage of conidia that are actually internalized after initial contact with airway epithelial cells. We determined this through an in vitro assay using an immortalized bronchial airway epithelial cell line known as BEAS-2B. Our results suggest a small fraction of conidia are internalized by BEAS-2B cells, while the majority stay adherent to the surface of cells or are washed away during sample processing. Internalization of conidia was observed at 6 h postchallenge and not prior. Our data also indicate conidia are rendered metabolically inactive within 3 h of challenge, suggesting BEAS-2B cells process a large number of conidia without internalization in this early time frame. We have also identified several host endocytosis markers that localize around internalized conidia as well as contribute to the processing of conidia. Understanding how these host endocytosis markers affect the processing of internal and/or external conidia may provide a novel avenue for therapeutic development. Aspergillus fumigatus is a ubiquitous mold that produces small airborne conidia capable of traversing deep into the respiratory system. Recognition, processing, and clearance of A. fumigatus conidia by bronchial airway epithelial cells are thought to be relevant to host defense and immune signaling. Using z-stack confocal microscopy, we observed that only 10 to 20% of adherent conidia from the AF293 clinical isolate are internalized by BEAS-2B cells 6 h postchallenge and not prior. Similar percentages of internalization were observed for the CEA10 clinical isolate. A large subset of both AF293 and CEA10 conidia are rendered metabolically inactive without internalization at 3 h postchallenge by BEAS-2B cells. A significantly larger percentage of CEA10 conidia are metabolically active at 9 and 12 h postchallenge in comparison to the AF293 isolate, demonstrating heterogeneity among clinical isolates. We identified 7 host markers (caveolin, flotillin-2, RAB5C, RAB8B, RAB7A, 2xFYVE, and FAPP1) that consistently localized around internalized conidia 9 h postchallenge. Transient gene silencing of RAB5C, PIK3C3, and flotillin-2 resulted in a larger population of metabolically active conidia. Our findings emphasize the abundance of both host phosphatidylinositol 3-phosphate (PI3P) and PI4P around internalized conidia, as well as the importance of class III PI3P kinase for conidial processing. Therapeutic development focused on RAB5C-, PIK3C3-, and flotillin-2-mediated pathways may provide novel opportunities to modulate conidial processing and internalization. Determination of how contacted, external conidia are processed by airway epithelial cells may also provide a novel avenue to generate host-targeted therapeutics. IMPORTANCE Conidia from the fungus Aspergillus fumigatus are notorious for their ability to stay airborne. This characteristic is believed to allow conidia to penetrate into the cleanest environments. Several hundred conidia are thought to be inhaled each day by a given individual and then expelled by mucociliary clearance. Given that airway epithelial cells make up a significant portion of the pulmonary-air interface, we set out to determine the percentage of conidia that are actually internalized after initial contact with airway epithelial cells. We determined this through an in vitro assay using an immortalized bronchial airway epithelial cell line known as BEAS-2B. Our results suggest a small fraction of conidia are internalized by BEAS-2B cells, while the majority stay adherent to the surface of cells or are washed away during sample processing. Internalization of conidia was observed at 6 h postchallenge and not prior. Our data also indicate conidia are rendered metabolically inactive within 3 h of challenge, suggesting BEAS-2B cells process a large number of conidia without internalization in this early time frame. We have also identified several host endocytosis markers that localize around internalized conidia as well as contribute to the processing of conidia. Understanding how these host endocytosis markers affect the processing of internal and/or external conidia may provide a novel avenue for therapeutic development.
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Abstract
Histoplasmosis, caused by the dimorphic environmental fungus Histoplasma capsulatum, is a major mycosis on the global stage. Acquisition of the fungus by mammalian hosts can be clinically silent or it can lead to life-threatening systemic disease, which can occur in immunologically intact or deficient hosts, albeit severe disease is more likely in the setting of compromised cellular immunity. H. capsulatum yeast cells are highly adapted to the mammalian host as they can effectively survive within intracellular niches in select phagocytic cells. Understanding the biological response by both the host and H. capsulatum will facilitate improved approaches to prevent and/or modify disease. This review presents our current understanding of the major pathogenic mechanisms involved in histoplasmosis.
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Affiliation(s)
- Jamie Mittal
- Department of Medicine (Infectious Diseases), Montefiore Medical Center, Bronx, NY, USA
| | - Maria G Ponce
- Department of Medicine (Infectious Diseases), Montefiore Medical Center, Bronx, NY, USA
| | - Inessa Gendlina
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY, USA
| | - Joshua D Nosanchuk
- Department of Medicine (Infectious Diseases), Albert Einstein College of Medicine, Bronx, NY, USA.
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
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16
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Shen Q, Beucler MJ, Ray SC, Rappleye CA. Macrophage activation by IFN-γ triggers restriction of phagosomal copper from intracellular pathogens. PLoS Pathog 2018; 14:e1007444. [PMID: 30452484 PMCID: PMC6277122 DOI: 10.1371/journal.ppat.1007444] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/03/2018] [Accepted: 10/30/2018] [Indexed: 11/19/2022] Open
Abstract
Copper toxicity and copper limitation can both be effective host defense mechanisms against pathogens. Tolerance of high copper by fungi makes toxicity as a defense mechanism largely ineffective against fungal pathogens. A forward genetic screen for Histoplasma capsulatum mutant yeasts unable to replicate within macrophages showed the Ctr3 copper transporter is required for intramacrophage proliferation. Ctr3 mediates copper uptake and is required for growth in low copper. Transcription of the CTR3 gene is induced by differentiation of H. capsulatum into pathogenic yeasts and by low available copper, but not decreased iron. Low expression of a CTR3 transcriptional reporter by intracellular yeasts implies that phagosomes of non-activated macrophages have moderate copper levels. This is further supported by the replication of Ctr3-deficient yeasts within the phagosome of non-activated macrophages. However, IFN-γ activation of phagocytes causes restriction of phagosomal copper as shown by upregulation of the CTR3 transcriptional reporter and by the failure of Ctr3-deficient yeasts, but not Ctr3 expressing yeasts, to proliferate within these macrophages. Accordingly, in a respiratory model of histoplasmosis, Ctr3-deficient yeasts are fully virulent during phases of the innate immune response but are attenuated after the onset of adaptive immunity. Thus, while technical limitations prevent direct measurement of phagosomal copper concentrations and copper-independent factors can influence gene expression, both the CTR3 promoter induction and the attenuation of Ctr3-deficient yeasts indicate activation of macrophages switches the phagosome from a copper-replete to a copper-depleted environment, forcing H. capsulatum reliance on Ctr3 for copper acquisition. Control of primary pathogens that infect phagocytes often requires adaptive immunity, but the mechanisms that convert host cells from permissive to antimicrobial states are only partially understood. The intracellular fungal pathogen Histoplasma capsulatum resides and proliferates within the macrophage phagosome. During innate immunity, macrophages which normally control fungi prove ineffective against H. capsulatum yeasts. At this stage, the phagosome of unactivated macrophages has ample copper that facilitates intracellular growth of Histoplasma but does not cause copper toxicity. However, the onset of adaptive immunity and the subsequent activation of macrophages decreases phagosomal copper and macrophages become less permissive to Histoplasma proliferation. IFN-γ acts as a key cytokine for switching the macrophage strategy by changing phagosomes from a copper-sufficient to a copper-depleted state in order to control intracellular pathogens. In such activated macrophages, H. capsulatum yeasts upregulate expression of the Ctr3 copper transporter to enable continued acquisition of essential copper.
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Affiliation(s)
- Qian Shen
- Department of Microbiology, Ohio State University, Columbus, OH, United States of America
| | - Matthew J. Beucler
- Department of Microbiology, Ohio State University, Columbus, OH, United States of America
| | - Stephanie C. Ray
- Department of Microbiology, Ohio State University, Columbus, OH, United States of America
| | - Chad A. Rappleye
- Department of Microbiology, Ohio State University, Columbus, OH, United States of America
- * E-mail:
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17
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Nicola AM, Albuquerque P, Paes HC, Fernandes L, Costa FF, Kioshima ES, Abadio AKR, Bocca AL, Felipe MS. Antifungal drugs: New insights in research & development. Pharmacol Ther 2018; 195:21-38. [PMID: 30347212 DOI: 10.1016/j.pharmthera.2018.10.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The need for better antifungal therapy is commonly accepted in view of the high mortality rates associated with systemic infections, the low number of available antifungal classes, their associated toxicity and the increasing number of infections caused by strains with natural or acquired resistance. The urgency to expand the range of therapeutic options for the treatment of fungal infections has led researchers in recent decades to seek alternative antifungal targets when compared to the conventional ones currently used. Although new potential targets are reported, translating the discoveries from bench to bedside is a long process and most of these drugs fail to reach the patients. In this review, we discuss the development of antifungal drugs focusing on the approach of drug repurposing and the search for novel drugs for classical targets, the most recently described gene targets for drug development, the possibilities of immunotherapy using antibodies, cytokines, therapeutic vaccines and antimicrobial peptides.
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Affiliation(s)
| | - Patrícia Albuquerque
- Faculty of Ceilândia, University of Brasília, Brazil; Graduate Programme in Microbial Biology, University of Brasília, Brazil
| | - Hugo Costa Paes
- Division of Clinical Medicine, University of Brasília Medical School, Brazil
| | - Larissa Fernandes
- Faculty of Ceilândia, University of Brasília, Brazil; Graduate Programme in Microbial Biology, University of Brasília, Brazil
| | - Fabricio F Costa
- Graduate Programme in Genomic Science and Biotechnology, Catholic University of Brasília, Brazil; MATTER, Chicago, IL, USA; Cancer Biology and Epigenomics Program, Ann & Robert Lurie Children's Hospital of Chicago Research Center, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, USA
| | - Erika Seki Kioshima
- Department of Clinical Analysis and Biomedicine, State University of Maringá, Paraná, Brazil
| | - Ana Karina Rodrigues Abadio
- School for Applied Social and Agricultural Sciences, State University of Mato Grosso, Nova Mutum Campus, Mato Grosso, Brazil
| | | | - Maria Sueli Felipe
- Graduate Programme in Genomic Science and Biotechnology, Catholic University of Brasília, Brazil; Department of Cell Biology, Institute of Biological Sciences, University of Brasília, Brazil.
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18
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Abstract
Metals are essential for life, and they play a central role in the struggle between infecting microbes and their hosts. In fact, an important aspect of microbial pathogenesis is the 'nutritional immunity', in which metals are actively restricted (or, in an extended definition of the term, locally enriched) by the host to hinder microbial growth and virulence. Consequently, fungi have evolved often complex regulatory networks, uptake and detoxification systems for essential metals such as iron, zinc, copper, nickel and manganese. These systems often differ fundamentally from their bacterial counterparts, but even within the fungal pathogens we can find common and unique solutions to maintain metal homeostasis. Thus, we here compare the common and species-specific mechanisms used for different metals among different fungal species-focusing on important human pathogens such as Candida albicans, Aspergillus fumigatus or Cryptococcus neoformans, but also looking at model fungi such as Saccharomyces cerevisiae or A. nidulans as well-studied examples for the underlying principles. These direct comparisons of our current knowledge reveal that we have a good understanding how model fungal pathogens take up iron or zinc, but that much is still to learn about other metals and specific adaptations of individual species-not the least to exploit this knowledge for new antifungal strategies.
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Affiliation(s)
- Franziska Gerwien
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Volha Skrahina
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Lydia Kasper
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Sascha Brunke
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
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19
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Tweedle JL, Xiong Y, Deepe GS. Pathogen–Host Interaction of Histoplasma capsulatum: an Update. Curr Fungal Infect Rep 2016; 10:153-162. [DOI: 10.1007/s12281-016-0267-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Gressler LT, Bordin AI, McQueen CM, Cohen ND, de Vargas AC. Chloroquine inhibits Rhodococcus equi replication in murine and foal alveolar macrophages by iron-starvation. Vet Microbiol 2016; 188:16-24. [PMID: 27139025 DOI: 10.1016/j.vetmic.2016.03.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/11/2016] [Accepted: 03/25/2016] [Indexed: 11/24/2022]
Abstract
Rhodococcus equi preferentially infects macrophages causing pyogranulomatous pneumonia in young foals. Both the vapA and rhbC genes are up-regulated in an iron (Fe)-deprived environment, such as that found within macrophages. Chloroquine (CQ) is a drug widely used against malaria that suppresses the intracellular availability of Fe in eukaryotic cells. The main objective of this study was to evaluate the ability of CQ to inhibit replication of virulent R. equi within murine (J774A.1) and foal alveolar macrophages (AMs) and to verify whether the mechanism of inhibition could be Fe-deprivation-dependent. CQ effect on R. equi extracellular survival and toxicity to J774A.1 were evaluated. R. equi survival within J774A.1 and foal AMs was evaluated under CQ (10 and 20μM), bovine saturated transferrin (bHTF), and bovine unsaturated transferrin (bATF) exposure. To explore the action mechanism of CQ, the superoxide anion production, the lysozyme activity, as well as the relative mRNA expression of vapA and rhbC were examined. CQ at≤20μM had no effect on R. equi extracellular multiplication and J774A.1 viability. Exposure to CQ significantly and markedly reduced survival of R. equi within J774A.1 and foal AMs. Treatment with bHTF did not reverse CQ effect on R. equi. Exposure to CQ did not affected superoxide anion production or lysozyme activity, however vapA and rhbC expression was significantly increased. Our results reinforce the hypothesis that intracellular availability of Fe is required for R. equi survival, and our initial hypothesis that CQ can limit replication of R. equi in J774A.1 and foal AMs, most likely by Fe starvation.
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21
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Woods JP. Revisiting old friends: Developments in understanding Histoplasma capsulatum pathogenesis. J Microbiol 2016; 54:265-76. [DOI: 10.1007/s12275-016-6044-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/02/2016] [Indexed: 12/27/2022]
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22
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Garfoot AL, Rappleye CA. Histoplasma capsulatum surmounts obstacles to intracellular pathogenesis. FEBS J 2015; 283:619-33. [PMID: 26235362 DOI: 10.1111/febs.13389] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 11/28/2022]
Abstract
The fungal pathogen Histoplasma capsulatum causes respiratory and disseminated disease, even in immunocompetent hosts. In contrast to opportunistic pathogens, which are readily controlled by phagocytic cells, H. capsulatum yeasts are able to infect macrophages, survive antimicrobial defenses, and proliferate as an intracellular pathogen. In this review, we discuss some of the molecular mechanisms that enable H. capsulatum yeasts to overcome obstacles to intracellular pathogenesis. H. capsulatum yeasts gain refuge from extracellular obstacles such as antimicrobial lung surfactant proteins by engaging the β-integrin family of phagocytic receptors to promote entry into macrophages. In addition, H. capsulatum yeasts conceal immunostimulatory β-glucans to avoid triggering signaling receptors such as the β-glucan receptor Dectin-1. H. capsulatum yeasts counteract phagocyte-produced reactive oxygen species by expression of oxidative stress defense enzymes including an extracellular superoxide dismutase and an extracellular catalase. Within the phagosome, H. capsulatum yeasts block phagosome acidification, acquire essential metals such as iron and zinc, and utilize de novo biosynthesis pathways to overcome nutritional limitations. These mechanisms explain how H. capsulatum yeasts avoid and negate macrophage defense strategies and establish a hospitable intracellular niche, making H. capsulatum a successful intracellular pathogen of macrophages.
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Affiliation(s)
- Andrew L Garfoot
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
| | - Chad A Rappleye
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
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23
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Boyce KJ, Andrianopoulos A. Fungal dimorphism: the switch from hyphae to yeast is a specialized morphogenetic adaptation allowing colonization of a host. FEMS Microbiol Rev 2015; 39:797-811. [DOI: 10.1093/femsre/fuv035] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 01/19/2023] Open
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24
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Dey S, Bishayi B. Killing of Staphylococcus aureus in murine macrophages by chloroquine used alone and in combination with ciprofloxacin or azithromycin. J Inflamm Res 2015; 8:29-47. [PMID: 25653549 PMCID: PMC4309780 DOI: 10.2147/jir.s76045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This study aimed to determine any alteration in the killing of Staphylococcus aureus in murine peritoneal macrophages when chloroquine (CQ) is used alone compared with when it is used in combination with ciprofloxacin (CIP) or azithromycin (AZM). The study also aimed to find out the implication of reactive oxygen species (ROS) production and cytokine release in the intracellular killing of S. aureus in macrophages. We present here data obtained with a model of S. aureus-infected mouse peritoneal macrophages in which the intracellular growth of the bacteria and the influence of antibiotics was monitored for 30, 60, and 90 minutes in the presence or absence of CQ along with the production of ROS and alteration in levels of antioxidant enzymes and cytokines. It was observed that S. aureus-triggered cytokine response was regulated when macrophages were co-cultured with CQ and AZM as compared with CQ stimulation only. It can be suggested that action of AZM in mediating bacterial killing is enhanced by the presence of CQ, indicating enhanced uptake of AZM during early infection that may be essential for bacteria killing by AZM. Reduction of oxidative stress burden on the S. aureus-infected macrophages may pave the way for better killing of internalized S. aureus by CQ plus ciprofloxacin (CIP) or CQ plus AZM. Based on these observations, one may speculate that in an inflammatory milieu, CQ loaded with AZM elicits a stronger proinflammatory response by increasing the intracellular uptake of AZM or CIP, thus enabling the immune system to mount a more robust and prolonged response against intracellular pathogens.
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Affiliation(s)
- Somrita Dey
- Department of Physiology, Immunology laboratory, University of Calcutta, University Colleges of Science and Technology, Calcutta, India
| | - Biswadev Bishayi
- Department of Physiology, Immunology laboratory, University of Calcutta, University Colleges of Science and Technology, Calcutta, India
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25
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Li Y, Wan Z, Liu W, Li R. Synergistic activity of chloroquine with fluconazole against fluconazole-resistant isolates of Candida species. Antimicrob Agents Chemother 2015; 59:1365-9. [PMID: 25512426 DOI: 10.1128/AAC.04417-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The in vitro activity of chloroquine and the interactions of chloroquine combined with fluconazole against 37 Candida isolates were tested using the broth microdilution, disk diffusion, and Etest susceptibility tests. Synergistic effect was detected with 6 of 9 fluconazole-resistant Candida albicans isolates, with Candida krusei ATCC 6258, and with all 12 fluconazole-resistant Candida tropicalis isolates.
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26
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Kasper L, Seider K, Gerwien F, Allert S, Brunke S, Schwarzmüller T, Ames L, Zubiria-Barrera C, Mansour MK, Becken U, Barz D, Vyas JM, Reiling N, Haas A, Haynes K, Kuchler K, Hube B. Identification of Candida glabrata genes involved in pH modulation and modification of the phagosomal environment in macrophages. PLoS One 2014; 9:e96015. [PMID: 24789333 PMCID: PMC4006850 DOI: 10.1371/journal.pone.0096015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/02/2014] [Indexed: 12/27/2022] Open
Abstract
Candida glabrata currently ranks as the second most frequent cause of invasive candidiasis. Our previous work has shown that C. glabrata is adapted to intracellular survival in macrophages and replicates within non-acidified late endosomal-stage phagosomes. In contrast, heat killed yeasts are found in acidified matured phagosomes. In the present study, we aimed at elucidating the processes leading to inhibition of phagosome acidification and maturation. We show that phagosomes containing viable C. glabrata cells do not fuse with pre-labeled lysosomes and possess low phagosomal hydrolase activity. Inhibition of acidification occurs independent of macrophage type (human/murine), differentiation (M1-/M2-type) or activation status (vitamin D3 stimulation). We observed no differential activation of macrophage MAPK or NFκB signaling cascades downstream of pattern recognition receptors after internalization of viable compared to heat killed yeasts, but Syk activation decayed faster in macrophages containing viable yeasts. Thus, delivery of viable yeasts to non-matured phagosomes is likely not triggered by initial recognition events via MAPK or NFκB signaling, but Syk activation may be involved. Although V-ATPase is abundant in C. glabrata phagosomes, the influence of this proton pump on intracellular survival is low since blocking V-ATPase activity with bafilomycin A1 has no influence on fungal viability. Active pH modulation is one possible fungal strategy to change phagosome pH. In fact, C. glabrata is able to alkalinize its extracellular environment, when growing on amino acids as the sole carbon source in vitro. By screening a C. glabrata mutant library we identified genes important for environmental alkalinization that were further tested for their impact on phagosome pH. We found that the lack of fungal mannosyltransferases resulted in severely reduced alkalinization in vitro and in the delivery of C. glabrata to acidified phagosomes. Therefore, protein mannosylation may play a key role in alterations of phagosomal properties caused by C. glabrata.
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Affiliation(s)
- Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Franziska Gerwien
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Tobias Schwarzmüller
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University, Vienna, Austria
| | - Lauren Ames
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Cristina Zubiria-Barrera
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Michael K. Mansour
- Massachusetts General Hospital, Department of Medicine, Division of Infectious Disease, Boston, Massachusetts, United States of America
| | | | - Dagmar Barz
- Institute for Transfusion Medicine, University Hospital, Jena, Germany
| | - Jatin M. Vyas
- Massachusetts General Hospital, Department of Medicine, Division of Infectious Disease, Boston, Massachusetts, United States of America
| | - Norbert Reiling
- Division of Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Borstel, Germany
| | - Albert Haas
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Ken Haynes
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Karl Kuchler
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University, Vienna, Austria
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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27
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Sahaza JH, Pérez-Torres A, Zenteno E, Taylor ML. Usefulness of the murine model to study the immune response against Histoplasma capsulatum infection. Comp Immunol Microbiol Infect Dis 2014; 37:143-52. [PMID: 24766724 DOI: 10.1016/j.cimid.2014.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/14/2014] [Accepted: 03/19/2014] [Indexed: 12/19/2022]
Abstract
The present paper is an overview of the primary events that are associated with the histoplasmosis immune response in the murine model. Valuable data that have been recorded in the scientific literature have contributed to an improved understanding of the clinical course of this systemic mycosis, which is caused by the dimorphic fungus Histoplasma capsulatum. Data must be analyzed carefully, given that misinterpretation could be generated because most of the available information is based on experimental host-parasite interactions that used inappropriate proceedings, i.e., the non-natural route of infection with the parasitic and virulent fungal yeast-phase, which is not the usual infective phase of the etiological agent of this mycosis. Thus, due to their versatility, complexity, and similarities with humans, several murine models have played a fundamental role in exploring the host-parasite interaction during H. capsulatum infection.
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Affiliation(s)
- Jorge H Sahaza
- Laboratorio de Inmunología de Hongos, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), México, DF 04510, Mexico; Unidad de Micología Médica y Experimental, Corporación para Investigaciones Biológicas, Medellín, Colombia
| | - Armando Pérez-Torres
- Laboratorio de Filogenia del Sistema Inmune de Piel y Mucosas, Departamento de Biología Celular y Tisular, Facultad de Medicina, UNAM, México, DF 04510, Mexico
| | - Edgar Zenteno
- Laboratorio de Inmunología, Departamento de Bioquímica, Facultad de Medicina, UNAM, México, DF 04510, Mexico
| | - Maria Lucia Taylor
- Laboratorio de Inmunología de Hongos, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), México, DF 04510, Mexico.
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Affiliation(s)
- Elmer Brummer
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University, Chiba, Japan
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Newman SL, Smulian AG. Iron uptake and virulence in Histoplasma capsulatum. Curr Opin Microbiol 2013; 16:700-7. [DOI: 10.1016/j.mib.2013.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 08/28/2013] [Accepted: 09/04/2013] [Indexed: 10/26/2022]
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Islahudin F, Ting KN, Pleass RJ, Avery SV. Reply to "chloroquine, an antifungal but also a fertility drug". Antimicrob Agents Chemother 2013; 57:5787. [PMID: 24123347 DOI: 10.1128/AAC.01688-13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kronstad JW, Hu G, Jung WH. An encapsulation of iron homeostasis and virulence in Cryptococcus neoformans. Trends Microbiol 2013; 21:457-65. [PMID: 23810126 DOI: 10.1016/j.tim.2013.05.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 05/24/2013] [Accepted: 05/29/2013] [Indexed: 02/07/2023]
Abstract
Vertebrate hosts actively sequester iron, and fungal and other pathogens must therefore adapt to a severe limitation in iron availability to cause disease. Recent studies reveal that the pathogenic fungus Cryptococcus neoformans overcomes iron limitation by multiple mechanisms that target transferrin and heme. The regulation of iron uptake is mediated by an interconnected set of transcription factors that include the master iron regulator Cir1 and the pH-responsive factor Rim101. These factors integrate iron homeostasis with a myriad of other functions including pH sensing, nutrient and stress signaling pathways, virulence factor elaboration, and cell wall biogenesis.
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Affiliation(s)
- James W Kronstad
- Department of Microbiology and Immunology, The Michael Smith Laboratories, University of British Columbia, Vancouver BC, V6T 1Z4, Canada.
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Henriet SSV, Jans J, Simonetti E, Kwon-Chung KJ, Rijs AJMM, Hermans PWM, Holland SM, de Jonge MI, Warris A. Chloroquine modulates the fungal immune response in phagocytic cells from patients with chronic granulomatous disease. J Infect Dis 2013; 207:1932-9. [PMID: 23482646 DOI: 10.1093/infdis/jit103] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Invasive aspergillosis is a major threat to patients with chronic granulomatous disease (CGD). Fungal pathogenesis is the result of a diminished antifungal capacity and dysregulated inflammation. A deficient NADPH-oxidase complex results in defective phagolysosomal alkalization. To investigate the contribution of defective pH regulation in phagocytes among patients with CGD during fungal pathogenesis, we evaluated the effect of the acidotropic, antimalarial drug chloroquine (CQ) on the antifungal capacity of polymorphonuclear cells (PMNs) and on the inflammatory response of peripheral blood mononuclear cells (PBMCs). Chloroquine exerted a direct pH-dependent antifungal effect on Aspergillus fumigatus and Aspergillus nidulans; it increased the antifungal activity of PMNs from patients with CGD at a significantly lower concentration, compared with the concentration for PMNs from healthy individuals; and decreased the hyperinflammatory state of PBMCs from patients with CGD, as observed by decreased tumor necrosis factor α and interleukin 1β release. Chloroquine targets both limbs of fungal pathogenesis and might be of great value in the clearance of invasive aspergillosis in patients with CGD.
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Affiliation(s)
- Stefanie S V Henriet
- Department of Pediatrics, Radboud University Nijmegen Medical Centre, The Netherlands.
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Isaac DT, Coady A, Van Prooyen N, Sil A. The 3-hydroxy-methylglutaryl coenzyme A lyase HCL1 is required for macrophage colonization by human fungal pathogen Histoplasma capsulatum. Infect Immun 2013; 81:411-20. [PMID: 23184522 DOI: 10.1128/IAI.00833-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Histoplasma capsulatum is a fungal respiratory pathogen that survives and replicates within the phagolysosome of macrophages. The molecular factors it utilizes to subvert macrophage antimicrobial defenses are largely unknown. Although the ability of H. capsulatum to prevent acidification of the macrophage phagolysosome is thought to be critical for intracellular survival, this hypothesis has not been tested since H. capsulatum mutants that experience decreased phagosomal pH have not been identified. In a screen to identify H. capsulatum genes required for lysis of bone marrow-derived macrophages (BMDMs), we identified an insertion mutation disrupting the H. capsulatum homolog of 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) lyase (HCL1). In addition to its inability to lyse macrophages, the hcl1 mutant had a severe growth defect in BMDMs, indicating that HMG CoA lyase gene function is critical for macrophage colonization. In other organisms, HMG CoA lyase catalyzes the last step in the leucine catabolism pathway. In addition, both fungi and humans deficient in HMG CoA lyase accumulate acidic intermediates as a consequence of their inability to catabolize leucine. Consistent with observations in other organisms, the H. capsulatum hcl1 mutant was unable to grow on leucine as the major carbon source, caused acidification of its growth medium in vitro, and resided in an acidified vacuole within macrophages. Mice infected with the hcl1 mutant took significantly longer to succumb to infection than mice infected with the wild-type strain. Taken together, these data indicate the importance of Hcl1 function in H. capsulatum replication in the harsh growth environment of the macrophage phagosome.
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Marathe SA, Sen M, Dasgupta I, Chakravortty D. Differential modulation of intracellular survival of cytosolic and vacuolar pathogens by curcumin. Antimicrob Agents Chemother. 2012;56:5555-5567. [PMID: 22890770 DOI: 10.1128/aac.00496-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Curcumin, a principal component of turmeric, acts as an immunomodulator regulating the host defenses in response to a diseased condition. The role of curcumin in controlling certain infectious diseases is highly controversial. It is known to alleviate symptoms of Helicobacter pylori infection and exacerbate that of Leishmania infection. We have evaluated the role of curcumin in modulating the fate of various intracellular bacterial pathogens. We show that pretreatment of macrophages with curcumin attenuates the infections caused by Shigella flexneri (clinical isolates) and Listeria monocytogenes and aggravates those caused by Salmonella enterica serovar Typhi CT18 (a clinical isolate), Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Yersinia enterocolitica. Thus, the antimicrobial nature of curcumin is not a general phenomenon. It modulated the intracellular survival of cytosolic (S. flexneri and L. monocytogenes) and vacuolar (Salmonella spp., Y. enterocolitica, and S. aureus) bacteria in distinct ways. Through colocalization experiments, we demonstrated that curcumin prevented the active phagosomal escape of cytosolic pathogens and enhanced the active inhibition of lysosomal fusion by vacuolar pathogens. A chloroquine resistance assay confirmed that curcumin retarded the escape of the cytosolic pathogens, thus reducing their inter- and intracellular spread. We have demonstrated that the membrane-stabilizing activity of curcumin is crucial for its differential effect on the virulence of the bacteria.
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Edwards JA, Rappleye CA. Histoplasma mechanisms of pathogenesis--one portfolio doesn't fit all. FEMS Microbiol Lett 2011; 324:1-9. [PMID: 22092757 PMCID: PMC3228276 DOI: 10.1111/j.1574-6968.2011.02363.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 01/15/2023] Open
Abstract
Histoplasma capsulatum is the leading cause of endemic mycosis in the world. Analyses of clinical isolates from different endemic regions show important diversity within the species. Recent molecular studies of two isolates, the Chemotype I NAm2 strain G217B and the Chemotype II Panamanian strain G186A, reveal significant genetic, structural, and molecular differences between these representative Histoplasma strains. Some of these variations have functional consequences, representing distinct molecular mechanisms that facilitate Histoplasma pathogenesis. The realization of Histoplasma strain diversity highlights the importance of characterizing Histoplasma virulence factors in the context of specific clinical strain isolates.
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Affiliation(s)
- Jessica A. Edwards
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, Ohio State University, 484 W. 12Avenue, Columbus, OH 43210, USA
| | - Chad A. Rappleye
- Departments of Microbiology and Internal Medicine, The Center for Microbial Interface Biology, Ohio State University, 484 W. 12Avenue, Columbus, OH 43210, USA
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Abstract
Histoplasma capsulatum is a dimorphic fungal pathogen that survives and replicates within macrophages (MΦ). Studies in human and murine MΦ demonstrate that the intracellular growth of H. capsulatum yeasts is exquisitely sensitive to the availability of iron. As H. capsulatum produces hydroxamate siderophores, we sought to determine if siderophores were required for intracellular survival in MΦ, and in a murine model of pulmonary histoplasmosis. The expression of SID1 (coding for L-ornithine-N(5)-monooxygenase) was silenced by RNA interference (RNAi) in H. capsulatum strain G217B, and abolished by gene targeting in strain G186AR. G217B SID1-silenced yeasts grew normally in rich medium, did not synthesize siderophores, and were unable to grow on apotransferrin-chelated medium. Their intracellular growth in human and murine MΦ was significantly decreased compared to wild type (WT) yeasts, but growth was restored to WT levels by the addition of exogenous iron, or restoration of SID1 expression. Similar results were obtained with G186AR Δsid1 yeasts. Compared to WT yeasts, G217B SID1-silenced yeasts demonstrated in C57BL/6 mice significantly reduced growth in the lungs and spleens seven days after infection, and 40% of the mice given a normally lethal inoculum of G217B SID1-silenced yeasts survived. These experiments demonstrate that: (1) SID1 expression is required for siderophore biosynthesis by H. capsulatum strain G217B, (2) SID1 expression is required for optimum intracellular growth in MΦ, and (3) inhibition of SID1 expression in vivo reduces the virulence of H. capsulatum yeasts.
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Affiliation(s)
- Jeremy Hilty
- Department of Internal Medicine, Division of Infectious Diseases, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0560, USA
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Winters MS, Spellman DS, Chan Q, Gomez FJ, Hernandez M, Catron B, Smulian AG, Neubert TA, Deepe GS. Histoplasma capsulatum proteome response to decreased iron availability. Proteome Sci 2008; 6:36. [PMID: 19108728 PMCID: PMC2645362 DOI: 10.1186/1477-5956-6-36] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 12/24/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A fundamental pathogenic feature of the fungus Histoplasma capsulatum is its ability to evade innate and adaptive immune defenses. Once ingested by macrophages the organism is faced with several hostile environmental conditions including iron limitation. H. capsulatum can establish a persistent state within the macrophage. A gap in knowledge exists because the identities and number of proteins regulated by the organism under host conditions has yet to be defined. Lack of such knowledge is an important problem because until these proteins are identified it is unlikely that they can be targeted as new and innovative treatment for histoplasmosis. RESULTS To investigate the proteomic response by H. capsulatum to decreasing iron availability we have created H. capsulatum protein/genomic databases compatible with current mass spectrometric (MS) search engines. Databases were assembled from the H. capsulatum G217B strain genome using gene prediction programs and expressed sequence tag (EST) libraries. Searching these databases with MS data generated from two dimensional (2D) in-gel digestions of proteins resulted in over 50% more proteins identified compared to searching the publicly available fungal databases alone. Using 2D gel electrophoresis combined with statistical analysis we discovered 42 H. capsulatum proteins whose abundance was significantly modulated when iron concentrations were lowered. Altered proteins were identified by mass spectrometry and database searching to be involved in glycolysis, the tricarboxylic acid cycle, lysine metabolism, protein synthesis, and one protein sequence whose function was unknown. CONCLUSION We have created a bioinformatics platform for H. capsulatum and demonstrated the utility of a proteomic approach by identifying a shift in metabolism the organism utilizes to cope with the hostile conditions provided by the host. We have shown that enzyme transcripts regulated by other fungal pathogens in response to lowering iron availability are also regulated in H. capsulatum at the protein level. We also identified H. capsulatum proteins sensitive to iron level reductions which have yet to be connected to iron availability in other pathogens. These data also indicate the complexity of the response by H. capsulatum to nutritional deprivation. Finally, we demonstrate the importance of a strain specific gene/protein database for H. capsulatum proteomic analysis.
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Cooney NM, Klein BS. Fungal adaptation to the mammalian host: it is a new world, after all. Curr Opin Microbiol 2008; 11:511-6. [PMID: 18955154 DOI: 10.1016/j.mib.2008.09.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 09/24/2008] [Accepted: 09/25/2008] [Indexed: 11/21/2022]
Abstract
Adaptation to environmental conditions is key to fungal survival during infection of human hosts. Although the host immune system is often considered the primary obstacle to fungal colonization, invading fungi must also contend with extreme abiotic stresses. Recent work with human pathogenic fungi has uncovered systems for detecting and responding to changes in temperature, carbon source, metal ion availability, pH, and gas tension. These systems play a major role in adaptation to the host niche and are essential factors for persistence in a mammalian host. Future investigations into fungal responses to these and other abiotic components of the host environment have the potential to uncover novel targets for anti-fungal therapy.
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40
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Szymczak WA, Deepe GS, Winters MS. The interface between virulence and host response to the pathogenic fungus Histoplasma capsulatum. Curr Fungal Infect Rep 2008. [DOI: 10.1007/s12281-008-0023-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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41
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Zarnowski R, Cooper KG, Brunold LS, Calaycay J, Woods JP. Histoplasma capsulatum secreted gamma-glutamyltransferase reduces iron by generating an efficient ferric reductant. Mol Microbiol 2008; 70:352-68. [PMID: 18761625 DOI: 10.1111/j.1365-2958.2008.06410.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The intracellular fungal pathogen Histoplasma capsulatum (Hc) resides in mammalian macrophages and causes respiratory and systemic disease. Iron limitation is an important host antimicrobial defence, and iron acquisition is critical for microbial pathogenesis. Hc displays several iron acquisition mechanisms, including secreted glutathione-dependent ferric reductase activity (GSH-FeR). We purified this enzyme from culture supernatant and identified a novel extracellular iron reduction strategy involving gamma-glutamyltransferase (Ggt1) activity. The 320 kDa complex was composed of glycosylated protein subunits of about 50 and 37 kDa. The purified enzyme exhibited gamma-glutamyl transfer activity as well as iron reduction activity in the presence of glutathione. We cloned and manipulated expression of the encoding gene. Overexpression or RNAi silencing affected both GGT and GSH-FeR activities concurrently. Enzyme inhibition experiments showed that the activity is complex and involves two reactions. First, Ggt1 initiates enzymatic breakdown of GSH by cleavage of the gamma-glutamyl bond and release of cysteinylglycine. Second, the thiol group of the released dipeptide reduces ferric to ferrous iron. A combination of kinetic properties of both reactions resulted in efficient iron reduction over a broad pH range. Our findings provide novel insight into Hc iron acquisition strategies and reveal a unique aspect of Ggt1 function in this dimorphic mycopathogen.
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Affiliation(s)
- Robert Zarnowski
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA.
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42
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Hilty J, Smulian AG, Newman SL. The Histoplasma capsulatum vacuolar ATPase is required for iron homeostasis, intracellular replication in macrophages and virulence in a murine model of histoplasmosis. Mol Microbiol 2008; 70:127-39. [PMID: 18699866 DOI: 10.1111/j.1365-2958.2008.06395.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Histoplasma capsulatum is a dimorphic fungal pathogen that survives and replicates within macrophages (Mphi). To identify specific genes required for intracellular survival, we utilized Agrobacterium tumefaciens-mediated mutagenesis, and screened for H. capsulatum insertional mutants that were unable to survive in human Mphi. One colony was identified that had an insertion within VMA1, the catalytic subunit A of the vacuolar ATPase (V-ATPase). The vma1 mutant (vma1::HPH) grew normally on iron-replete medium, but not on iron-deficient media. On iron-deficient medium, the growth of the vma1 mutant was restored in the presence of wild-type (WT) H. capsulatum yeasts, or the hydroxamate siderophore, rhodotorulic acid. However, the inability to replicate within Mphi was only partially restored by the addition of exogenous iron. The vma1::HPH mutant also did not grow as a mold at 28 degrees C. Complementation of the mutant (vma/VMA1) restored its ability to replicate in Mphi, grow on iron-poor medium and grow as a mold at 28 degrees C. The vma1::HPH mutant was avirulent in a mouse model of histoplasmosis, whereas the vma1/VMA1 strain was as pathogenic as WT yeasts. These studies demonstrate the importance of V-ATPase function in the pathogenicity of H. capsulatum, in iron homeostasis and in fungal dimorphism.
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Affiliation(s)
- Jeremy Hilty
- Department of Internal Medicine, Division of Infectious Diseases, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Abstract
BACKGROUND To successfully sustain an infection, nearly all bacteria, fungi and protozoa require a continuous supply of host iron. METHODS Literature review. RESULTS Mechanisms of microbial iron acquisition are determinants for the kinds of cells, tissues and hosts in which pathogens can flourish. As a corollary, hosts possess an array of iron withholding devices whereby they can suppress or abort microbial invasions. GENERAL SIGNIFICANCE Awareness of environmental and behavioral methods that can prevent iron loading plus development of pharmaceutical agents that can block microbial access to iron may help to reduce our dependence on antibiotics.
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Abrantes P, Dimopoulos G, Grosso AR, do Rosário VE, Silveira H. Chloroquine mediated modulation of Anopheles gambiae gene expression. PLoS One 2008; 3:e2587. [PMID: 18596975 PMCID: PMC2432468 DOI: 10.1371/journal.pone.0002587] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 05/20/2008] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Plasmodium development in the mosquito is crucial for malaria transmission and depends on the parasite's interaction with a variety of cell types and specific mosquito factors that have both positive and negative effects on infection. Whereas the defensive response of the mosquito contributes to a decrease in parasite numbers during these stages, some components of the blood meal are known to favor infection, potentiating the risk of increased transmission. The presence of the antimalarial drug chloroquine in the mosquito's blood meal has been associated with an increase in Plasmodium infectivity for the mosquito, which is possibly caused by chloroquine interfering with the capacity of the mosquito to defend against the infection. METHODOLOGY/PRINCIPAL FINDINGS In this study, we report a detailed survey of the Anopheles gambiae genes that are differentially regulated by the presence of chloroquine in the blood meal, using an A. gambiae cDNA microarray. The effect of chloroquine on transcript abundance was evaluated separately for non-infected and Plasmodium berghei-infected mosquitoes. Chloroquine was found to affect the abundance of transcripts that encode proteins involved in a variety of processes, including immunity, apoptosis, cytoskeleton and the response to oxidative stress. This pattern of differential gene expression may explain the weakened mosquito defense response which accounts for the increased infectivity observed in chloroquine-treated mosquitoes. CONCLUSIONS/SIGNIFICANCE The results of the present study suggest that chloroquine can interfere with several putative mosquito mechanisms of defense against Plasmodium at the level of gene expression and highlight the need for a better understanding of the impacts of antimalarial agents on parasite transmission.
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Affiliation(s)
- Patrícia Abrantes
- Centro de Malária e Outras Doenças Tropicais-LA/ UEI de Malária, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal.
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Chao LY, Marletta MA, Rine J. Sre1, an Iron-Modulated GATA DNA-Binding Protein of Iron-Uptake Genes in the Fungal Pathogen Histoplasma capsulatum. Biochemistry 2008; 47:7274-83. [DOI: 10.1021/bi800066s] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lily Y. Chao
- Department of Molecular and Cell Biology, Department of Chemistry, Department of Plant and Microbial Biology, California Institute for Quantitative Biosciences, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| | - Michael A. Marletta
- Department of Molecular and Cell Biology, Department of Chemistry, Department of Plant and Microbial Biology, California Institute for Quantitative Biosciences, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
| | - Jasper Rine
- Department of Molecular and Cell Biology, Department of Chemistry, Department of Plant and Microbial Biology, California Institute for Quantitative Biosciences, and Division of Physical Biosciences, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720-3220
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Zarnowski R, Dobrzyn A, Ntambi JM, Woods JP. Ferrous, but not ferric, iron maintains homeostasis in Histoplasma capsulatum triacylglycerides. Curr Microbiol 2008; 57:153-7. [PMID: 18506523 DOI: 10.1007/s00284-008-9168-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2008] [Accepted: 03/18/2008] [Indexed: 11/27/2022]
Abstract
Iron is an indispensable micronutrient for virtually all microorganisms, where it acts as a cofactor of many enzymes involved in regulation of multiple cellular and physiological functions. This metal is also considered an important determinant contributing to the pathogenesis of fungal infectious diseases, and therefore the identification of iron-regulated metabolic processes occurring within the invading fungal cell can help the development of new antifungal therapeutic strategies. In this study, we examined relationships between iron availability and neutral storage lipids in Histoplasma capsulatum, a dimorphic fungus responsible for the most common respiratory and systemic mycosis in humans. Yeast cells were grown in a defined minimal medium supplemented with or without iron. Lipids were extracted from cells at the log and late stationary growth phases, then separated by thin-layer chromatography, and fatty acids were analyzed by gas chromatography. A culture age-related decrease in the unsaturated fatty acid content was observed in all four neutral lipid classes examined. Iron-related alterations could be seen in relation to triacylglycerol and free fatty acid pools, whereas no iron-dependent effects were detected in diacylglycerol and steryl ester fractions. Regarding triacylglycerols, the presence of iron positively affected the content of unsaturated fatty acids, and this stabilizing action of iron was notably increased when ferrous ions were added. Subsequent iron uptake studies showed a definite preference of H. capsulatum to acquire iron in its reduced, more soluble, ferrous form, and therefore, the availability of iron may be the underlying reason for the observed iron-maintained homeostasis in H. capsulatum triacylglycerols.
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Affiliation(s)
- Robert Zarnowski
- Department of Medical Microbiology and Immunology, University of Wisconsin, 416 Service Memorial Institute, 1300 University Avenue, Madison, WI 53705, USA.
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Hwang LH, Mayfield JA, Rine J, Sil A. Histoplasma requires SID1, a member of an iron-regulated siderophore gene cluster, for host colonization. PLoS Pathog 2008; 4:e1000044. [PMID: 18404210 PMCID: PMC2275787 DOI: 10.1371/journal.ppat.1000044] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 03/13/2008] [Indexed: 11/26/2022] Open
Abstract
The macrophage is the primary host cell for the fungal pathogen Histoplasma capsulatum during mammalian infections, yet little is known about fungal genes required for intracellular replication in the host. Since the ability to scavenge iron from the host is important for the virulence of most pathogens, we investigated the role of iron acquisition in H. capsulatum pathogenesis. H. capsulatum acquires iron through the action of ferric reductases and the production of siderophores, but the genes responsible for these activities and their role in virulence have not been determined. We identified a discrete set of co-regulated genes whose transcription is induced under low iron conditions. These genes all appeared to be involved in the synthesis, secretion, and utilization of siderophores. Surprisingly, the majority of these transcriptionally co-regulated genes were found clustered adjacent to each other in the genome of the three sequenced strains of H. capsulatum, suggesting that their proximity might foster coordinate gene regulation. Additionally, we identified a consensus sequence in the promoters of all of these genes that may contribute to iron-regulated gene expression. The gene set included L-ornithine monooxygenase (SID1), the enzyme that catalyzes the first committed step in siderophore production in other fungi. Disruption of SID1 by allelic replacement resulted in poor growth under low iron conditions, as well as a loss of siderophore production. Strains deficient in SID1 showed a significant growth defect in murine bone-marrow-derived macrophages and attenuation in the mouse model of infection. These data indicated that H. capsulatum utilizes siderophores in addition to other iron acquisition mechanisms for optimal growth during infection. Fungal infections are a growing public health threat, particularly for immunocompromised individuals such as people with AIDS, organ transplant recipients, and cancer patients. Present antifungal therapies are often highly toxic and resistance to these therapies continues to rise. Histoplasma capsulatum is a pathogenic fungus that infects humans, causing pulmonary and systemic disease. It is the most common cause of fungal respiratory infection in the world, and is endemic to the Mississippi and Ohio River valleys of the United States. H. capsulatum produces small molecules, called siderophores, to acquire iron, an essential nutrient. We have identified genes that are involved in the synthesis of siderophores in this fungus and have found that siderophore production in H. capsulatum is important for its virulence. Since siderophore production is confined to microbes and plays no role in human biology, it is an excellent target for rational drug design.
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Affiliation(s)
- Lena H. Hwang
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Jacob A. Mayfield
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California, Berkeley, California, United States of America
| | - Jasper Rine
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, University of California, Berkeley, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
- * E-mail:
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Rolain JM, Colson P, Raoult D. Recycling of chloroquine and its hydroxyl analogue to face bacterial, fungal and viral infections in the 21st century. Int J Antimicrob Agents 2007; 30:297-308. [PMID: 17629679 PMCID: PMC7126847 DOI: 10.1016/j.ijantimicag.2007.05.015] [Citation(s) in RCA: 286] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 05/09/2007] [Indexed: 12/17/2022]
Abstract
Chloroquine (CQ) and its hydroxyl analogue hydroxychloroquine (HCQ) are weak bases with a half-century long use as antimalarial agents. Apart from this antimalarial activity, CQ and HCQ have gained interest in the field of other infectious diseases. One of the most interesting mechanisms of action is that CQ leads to alkalinisation of acid vesicles that inhibit the growth of several intracellular bacteria and fungi. The proof of concept of this effect was first used to restore intracellular pH allowing antibiotic efficacy for Coxiella burnetii, the agent of Q fever, and doxycycline plus HCQ is now the reference treatment for chronic Q fever. There is also strong evidence of a similar effect in vitro against Tropheryma whipplei, the agent of Whipple's disease, and a clinical trial is in progress. Other bacteria and fungi multiply in an acidic environment and encouraging in vitro data suggest that this concept may be generalised for all intracellular organisms that multiply in an acidic environment. For viruses, CQ led to inhibition of uncoating and/or alteration of post-translational modifications of newly synthesised proteins, especially inhibition of glycosylation. These effects have been well described in vitro for many viruses, with human immunodeficiency virus (HIV) being the most studied. Preliminary in vivo clinical trials suggest that CQ alone or in combination with antiretroviral drugs might represent an interesting way to treat HIV infection. In conclusion, our review re-emphasises the paradigm that activities mediated by lysosomotropic agents may offer an interesting weapon to face present and future infectious diseases worldwide.
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Affiliation(s)
- Jean-Marc Rolain
- Unité des Rickettsies, CNRS UMR 6020, Université de la Méditerranée, Faculté de Médecine et de Pharmacie, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 5, France.
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Dias-Melicio LA, Calvi SA, Bordon AP, Golim MA, Peraçoli MTS, Soares AMVC. Chloroquine is therapeutic in murine experimental model of paracoccidioidomycosis. ACTA ACUST UNITED AC 2007; 50:133-43. [PMID: 17456179 DOI: 10.1111/j.1574-695x.2007.00243.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chloroquine, due to its basic properties, has been shown to prevent the release of iron from holotransferrin, thereby interfering with normal iron metabolism in a variety of cell types. We have studied the effects of chloroquine on the evolution of experimental paracoccidioidomycosis by evaluating the viable fungal recovery from lung, liver and spleen from infected mice and H(2)O(2), NO production, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, IL-10 levels and transferrin receptor (TfR) expression from uninfected and infected peritoneal macrophages. Chloroquine caused a significant decrease in the viable fungal recovery from all organs tested, during all periods of evaluation. Peritoneal macrophages from chloroquine-treated infected mice showed higher H(2)O(2) production and TfR expression, and decreased levels of NO, endogenous and stimulated-TNF-alpha, IL-6 and IL-10 during the three evaluated periods. However, despite its suppressor effects on the macrophage function, the chloroquine therapeutic effect upon murine paracoccidioidomycosis was probably due to its effect on iron metabolism, blocking iron uptake by cells, and consequently restricting iron to fungus growth and survival.
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Affiliation(s)
- Luciane Alarcão Dias-Melicio
- Department of Microbiology and Immunology, Biosciences Institute, São Paulo State University, São Paulo, Brazil.
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Dias-Melicio LA, Moreira AP, Calvi SA, Soares AMVDC. Chloroquine inhibits Paracoccidioides brasiliensis survival within human monocytes by limiting the availability of intracellular iron. Microbiol Immunol 2006; 50:307-14. [PMID: 16625052 DOI: 10.1111/j.1348-0421.2006.tb03798.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanisms used by Paracoccidioides brasiliensis(Pb 18) to survive into monocytes are not clear. Cellular iron metabolism is of critical importance to the growth of several intracellular pathogens, including P. brasiliensis, whose capacity to multiply in mononuclear phagocytes is dependent on the availability of intracellular iron. Chloroquine, by virtue of its basic properties, has been shown to prevent release of iron from holotransferrin by raising endocytic and lysosomal pH, and thereby interfering with normal iron metabolism. Then, in view of this, we have studied the effects of CHLOR on P. brasiliensis multiplication in human monocytes and its effect on the murine paracoccidioidomycosis. CHLOR induced human monocytes to kill P. brasiliensis. The effect of CHLOR was reversed by FeNTA, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. CHLOR treatment of Pb 18-infected BALB/c mice significantly reduced the viable fungi recovery from lungs, during three different periods of evaluation, in a dose-dependent manner. This study demonstrates that iron is of critical importance to the survival of P. brasiliensis yeasts within human monocytes and the CHLOR treatment in vitro induces Pb 18 yeast-killing by monocytes by restricting the availability of intracellular iron. Besides, the CHLOR treatment in vivo significantly reduces the number of organisms in the lungs of Pb-infected mice protecting them from several infections. Thus, CHLOR was effective in the treatment of murine paracoccidioidomycosis, suggesting the potential use of this drug in patients' treatment.
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Affiliation(s)
- Luciane Alarcão Dias-Melicio
- Department of Microbiology and Immunology, Biosciences Institute, São Paulo State University, Botucatu, S.P, Brazil
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