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Cissé OH, Ma L, Kovacs JA. Retracing the evolution of Pneumocystis species, with a focus on the human pathogen Pneumocystis jirovecii. Microbiol Mol Biol Rev 2024; 88:e0020222. [PMID: 38587383 DOI: 10.1128/mmbr.00202-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024] Open
Abstract
SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.
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Affiliation(s)
- Ousmane H Cissé
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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Meier CS, Pagni M, Richard S, Mühlethaler K, Almeida JMGCF, Nevez G, Cushion MT, Calderón EJ, Hauser PM. Fungal antigenic variation using mosaicism and reassortment of subtelomeric genes' repertoires. Nat Commun 2023; 14:7026. [PMID: 37919276 PMCID: PMC10622565 DOI: 10.1038/s41467-023-42685-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023] Open
Abstract
Surface antigenic variation is crucial for major pathogens that infect humans. To escape the immune system, they exploit various mechanisms. Understanding these mechanisms is important to better prevent and fight the deadly diseases caused. Those used by the fungus Pneumocystis jirovecii that causes life-threatening pneumonia in immunocompromised individuals remain poorly understood. Here, though this fungus is currently not cultivable, our detailed analysis of the subtelomeric sequence motifs and genes encoding surface proteins suggests that the system involves the reassortment of the repertoire of ca. 80 non-expressed genes present in each strain, from which single genes are retrieved for mutually exclusive expression. Dispersion of the new repertoires, supposedly by healthy carrier individuals, appears very efficient because identical alleles are observed in patients from different countries. Our observations reveal a unique strategy of antigenic variation. They also highlight the possible role in genome rearrangements of small imperfect mirror sequences forming DNA triplexes.
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Affiliation(s)
- Caroline S Meier
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Sophie Richard
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Konrad Mühlethaler
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - João M G C F Almeida
- UCIBIO, Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Gilles Nevez
- Laboratoire de Parasitologie et Mycologie, Hôpital de La Cavale Blanche, CHU de Brest, Brest, France
- Infections respiratoires fongiques (IFR), Université d'Angers, Université de Brest, Brest, France
| | - Melanie T Cushion
- Department of Internal Medicine, Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
- Cincinnati VAMC, Medical Research Service, Cincinnati, OH, 45220, USA
| | - Enrique J Calderón
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocίo/Consejo Superior de Investigaciones Cientίficas/Universidad de Sevilla, Seville, Spain
- Centro de Investigación Biomédica en Red de Epidemiologίa y Salud Pública, Servicio de Medicina Interna, Hospital Universitario Virgen del Rocίo, Departamento de Medicina, Facultad de Medicina, Seville, Spain
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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Babb-Biernacki SJ, Esselstyn JA, Doyle VP. Predicting Species Boundaries and Assessing Undescribed Diversity in Pneumocystis, an Obligate Lung Symbiont. J Fungi (Basel) 2022; 8:jof8080799. [PMID: 36012788 PMCID: PMC9409666 DOI: 10.3390/jof8080799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 02/04/2023] Open
Abstract
Far more biodiversity exists in Fungi than has been described, or could be described in several lifetimes, given current rates of species discovery. Although this problem is widespread taxonomically, our knowledge of animal-associated fungi is especially lacking. Fungi in the genus Pneumocystis are obligate inhabitants of mammal lungs, and they have been detected in a phylogenetically diverse array of species representing many major mammal lineages. The hypothesis that Pneumocystis cospeciate with their mammalian hosts suggests that thousands of Pneumocystis species may exist, potentially equal to the number of mammal species. However, only six species have been described, and the true correspondence of Pneumocystis diversity to host species boundaries is unclear. Here, we use molecular species delimitation to estimate the boundaries of Pneumocystis species sampled from 55 mammal species representing eight orders. Our results suggest that Pneumocystis species often colonize several closely related mammals, especially those in the same genus. Using the newly estimated ratio of fungal to host diversity, we estimate ≈4600 to 6250 Pneumocystis species inhabit the 6495 currently recognized extant mammal species. Additionally, we review the literature and find that only 240 (~3.7%) mammal species have been screened for Pneumocystis, and many detected Pneumocystis lineages are not represented by any genetic data. Although crude, our findings challenge the dominant perspective of strict specificity of Pneumocystis to their mammal hosts and highlight an abundance of undescribed diversity.
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Affiliation(s)
- Spenser J. Babb-Biernacki
- Museum of Natural Science and Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA;
- Correspondence:
| | - Jacob A. Esselstyn
- Museum of Natural Science and Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA;
| | - Vinson P. Doyle
- Department of Plant Pathology and Crop Physiology, Louisiana State University AgCenter, Baton Rouge, LA 70809, USA;
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Schmid-Siegert E, Richard S, Luraschi A, Mühlethaler K, Pagni M, Hauser PM. Expression Pattern of the Pneumocystis jirovecii Major Surface Glycoprotein Superfamily in Patients with Pneumonia. J Infect Dis 2021; 223:310-318. [PMID: 32561915 DOI: 10.1093/infdis/jiaa342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/11/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The human pathogen Pneumocystis jirovecii harbors 6 families of major surface glycoproteins (MSGs) encoded by a single gene superfamily. MSGs are presumably responsible for antigenic variation and adhesion to host cells. The genomic organization suggests that a single member of family I is expressed at a given time per cell, whereas members of the other families are simultaneously expressed. METHODS We analyzed RNA sequences expressed in several clinical samples, using specific weighted profiles for sorting of reads and calling of single-nucleotide variants to estimate the diversity of the expressed genes. RESULTS A number of different isoforms of at least 4 MSG families were expressed simultaneously, including isoforms of family I, for which confirmation was obtained in the wet laboratory. CONCLUSION These observations suggest that every single P. jirovecii population is made of individual cells with distinct surface properties. Our results enhance our understanding of the unique antigenic variation system and cell surface structure of P. jirovecii.
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Affiliation(s)
| | - Sophie Richard
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Amanda Luraschi
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Konrad Mühlethaler
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Marco Pagni
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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Latinne A, Chen HW, Kuo CC, Lorica R, Singleton G, Stuart A, Malbas FF, Demanche C, Chabé M, Michaux J, Morand S. Revisiting the Pneumocystis host specificity paradigm and transmission ecology in wild Southeast Asian rodents. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 93:104978. [PMID: 34175480 DOI: 10.1016/j.meegid.2021.104978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/04/2021] [Accepted: 06/21/2021] [Indexed: 01/16/2023]
Abstract
Pneumocystis fungi are opportunistic parasites of mammalian lungs whose evolution, ecology and host specificity in natural host populations remain poorly understood and controversial. Using an extensive collection of 731 lung samples from 27 rodent species sampled in five Southeast Asian countries, and nested PCR amplification of mitochondrial and nuclear genes, we investigated the host specificity and genetic structure of Pneumocystis lineages infecting wild rodents. We also identified the rodent species playing a central role in the transmission of these parasites using network analysis and centrality measurement and we characterized the environmental conditions allowing Pneumocystis infection in Southeast Asia using generalized linear mixed models. Building upon an unprecedented Pneumocystis sampling from numerous rodent species belonging to closely related genera, our findings provide compelling evidence that the host specificity of Pneumocystis lineages infecting rodents is not restricted to a single host species or genus as often presented in the literature but it encompasses much higher taxonomic levels and more distantly related rodent host species. The phylogenetic species status at both mitochondrial and nuclear genetic markers of at least three new Pneumocystis lineages, highly divergent from Pneumocystis species currently described, is also suggested by our data. Our models show that the probability of Pneumocystis infection in rodent hosts is positively correlated to environmental variables reflecting habitat fragmentation and landscape patchiness. Synanthropic and habitat-generalist rodents belonging to the Rattus, Sundamys and Bandicota genera played a role of bridge host species for Pneumocystis spreading in these heterogeneous habitats, where they can reach high population densities. These are critical findings improving our understanding of the ecology of these enigmatic parasites and the role played by cospeciation and host switches in their evolution. Our results also confirmed the role of land-use change and habitat fragmentation in parasite amplification and spillover in rodents.
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Affiliation(s)
- Alice Latinne
- Wildlife Conservation Society, Viet Nam Country Program, Ha Noi, Viet Nam; Wildlife Conservation Society, Health Program, Bronx, NY, USA; Université de Liège, Laboratoire de Génétique de la Conservation, GeCoLAB, 4000 Liège, Belgium.
| | - Hsuan-Wien Chen
- Department of Biological Resources, National Chiayi University, Chiayi, Taiwan
| | - Chi-Chien Kuo
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Renee Lorica
- International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines
| | - Grant Singleton
- International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines; Natural Resource Institute, University of Greenwich, Chatham Maritime, Kent, UK
| | - Alex Stuart
- International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines
| | - Fedelino F Malbas
- Research Institute for Tropical Medicine, Department of Health, Muntinlupa, Metro Manila, Philippines
| | - Christine Demanche
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Magali Chabé
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Johan Michaux
- Université de Liège, Laboratoire de Génétique de la Conservation, GeCoLAB, 4000 Liège, Belgium; Animal Santé Territoire Risque Environnement- Unité Mixe de Recherche 117 (ASTRE) Univ. Montpellier, Centre International de Recherche Agronomique pour le Développement (CIRAD), Institut National de la Recherche Agronomique, 34398 Montpellier, France
| | - Serge Morand
- University of Montpellier, Institut des Sciences de l'Evolution, CNRS-IRD, Montpellier, France; University of Kasetsart, Faculty of Veterinary Technology, ASTRE-CIRAD, Bangkok, Thailand
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Diotti R, Esposito M, Shen CH. Telomeric and Sub-Telomeric Structure and Implications in Fungal Opportunistic Pathogens. Microorganisms 2021; 9:microorganisms9071405. [PMID: 34209786 PMCID: PMC8305976 DOI: 10.3390/microorganisms9071405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/11/2021] [Accepted: 06/25/2021] [Indexed: 12/28/2022] Open
Abstract
Telomeres are long non-coding regions found at the ends of eukaryotic linear chromosomes. Although they have traditionally been associated with the protection of linear DNA ends to avoid gene losses during each round of DNA replication, recent studies have demonstrated that the role of these sequences and their adjacent regions go beyond just protecting chromosomal ends. Regions nearby to telomeric sequences have now been identified as having increased variability in the form of duplications and rearrangements that result in new functional abilities and biodiversity. Furthermore, unique fungal telomeric and chromatin structures have now extended clinical capabilities and understanding of pathogenicity levels. In this review, telomere structure, as well as functional implications, will be examined in opportunistic fungal pathogens, including Aspergillus fumigatus, Candida albicans, Candida glabrata, and Pneumocystis jirovecii.
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Affiliation(s)
- Raffaella Diotti
- Department of Biological Sciences, Bronx Community College, City University of New York, New York, NY 10453, USA;
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
| | - Michelle Esposito
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
- Department of Biology, College of Staten Island, City University of New York, New York, NY 10314, USA
| | - Chang Hui Shen
- The Graduate Center, PhD Program in Biology, City University of New York, New York, NY 10016, USA;
- Department of Biology, College of Staten Island, City University of New York, New York, NY 10314, USA
- The Graduate Center, PhD Program in Biochemistry, City University of New York, New York, NY 10016, USA
- Institute for Macromolecular Assemblies, City University of New York, New York, NY 10031, USA
- Correspondence: ; Tel.: +1-(718)-982-3998; Fax: +1-(718)-982-3852
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Affiliation(s)
- Spenser J Babb-Biernacki
- Museum of Natural Science and Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Jacob A Esselstyn
- Museum of Natural Science and Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Vinson P Doyle
- Department of Plant Pathology and Crop Physiology, Louisiana State University AgCenter, Baton Rouge, Louisiana, United States of America
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Detection of anti-Pneumocystis jirovecii antibodies in human serum using a recombinant synthetic multi-epitope kexin-based antigen. Eur J Clin Microbiol Infect Dis 2020; 39:2205-2209. [PMID: 32557324 PMCID: PMC7561569 DOI: 10.1007/s10096-020-03936-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/26/2020] [Indexed: 11/22/2022]
Abstract
Interest in the detection of specific anti-Pneumocystis jirovecii antibodies has emerged as less-invasive alternative diagnostic approaches. Here is presented the performance of an ELISA based on a recombinant synthetic multi-epitope kexin 1 (Kex1) antigen of P. jirovecii, previously developed. Results showed that IgM anti-Kex1 levels were found significantly increased in patients with Pneumocystis pneumonia (PcP) compared with non-PcP cases (p < 0.001), allowing a diagnostic performance of PcP with a 70.8% sensitivity and a 75.0% specificity. These results suggest that this Kex1-based ELISA is a promising tool toward the serodiagnosis of PcP when the standard methods are difficult to perform.
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Min K, Neiman AM, Konopka JB. Fungal Pathogens: Shape-Shifting Invaders. Trends Microbiol 2020; 28:922-933. [PMID: 32474010 DOI: 10.1016/j.tim.2020.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/24/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022]
Abstract
Fungal infections are on the rise due to new medical procedures that have increased the number of immune compromised patients, antibacterial antibiotics that disrupt the microbiome, and increased use of indwelling medical devices that provide sites for biofilm formation. Key to understanding the mechanisms of pathogenesis is to determine how fungal morphology impacts virulence strategies. For example, small budding cells use very different strategies to disseminate compared with long hyphal filaments. Furthermore, cell morphology must be monitored in the host, as many fungal pathogens change their shape to disseminate into new areas, acquire nutrients, and avoid attack by the immune system. This review describes the shape-shifting alterations in morphogenesis of human fungal pathogens and how they influence virulence strategies.
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Affiliation(s)
- Kyunghun Min
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
| | - Aaron M Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - James B Konopka
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA.
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Tomás AL, de Almeida MP, Cardoso F, Pinto M, Pereira E, Franco R, Matos O. Development of a Gold Nanoparticle-Based Lateral-Flow Immunoassay for Pneumocystis Pneumonia Serological Diagnosis at Point-of-Care. Front Microbiol 2019; 10:2917. [PMID: 31921081 PMCID: PMC6931265 DOI: 10.3389/fmicb.2019.02917] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/03/2019] [Indexed: 12/29/2022] Open
Abstract
Pneumocystis jirovecii pneumonia (PcP) is a major human immunodeficiency virus (HIV)-related illness, rising among immunocompromised non-HIV patients and in developing countries. Presently, the diagnosis requires respiratory specimens obtained through invasive and costly techniques that are difficult to perform in all patients or implement in all economic settings. Therefore, the development of a faster, cost-effective, non-invasive and field-friendly test to diagnose PcP would be a significant advance. In this study, recombinant synthetic antigens (RSA) of P. jirovecii's major surface glycoprotein (Msg) and kexin-like serine protease (Kex1) were produced and purified. These RSA were applied as antigenic tools in immunoenzymatic assays for detection of specific anti-P. jirovecii antibodies (IgG and IgM) in sera of patients with (n = 48) and without (n = 28) PcP. Results showed that only IgM anti-P. jirovecii levels were significantly increased in patients with PcP compared with patients without P. jirovecii infection (p ≤ 0.001 with both RSA). Thus, two strip lateral flow immunoassays (LFIA), based on the detection of specific IgM anti-P. jirovecii antibodies in human sera samples, were developed using the innovative association of P. jirovecii's RSA with spherical gold nanoparticles (AuNPs). For that, alkanethiol-functionalized spherical AuNPs with ca. ~40 nm in diameter were synthetized and conjugated with the two RSA (Msg or Kex1) produced. These AuNP-RSA conjugates were characterized by agarose gel electrophoresis (AGE) and optimized to improve their ability to interact specifically with serum IgM anti-P. jirovecii antibodies. Finally, two LFIA prototypes were developed and tested with pools of sera from patients with (positive sample) and without (negative sample) PcP. Both LFIA had the expected performance, namely, the presence of a test and control red colored lines with the positive sample, and only a control red colored line with the negative sample. These results provide valuable insights into the possibility of PcP serodiagnosis at point-of-care. The optimization, validation and implementation of this strip-based approach may help to reduce the high cost of medical diagnosis and subsequent treatment of PcP both in industrialized and low-income regions, helping to manage the disease all around the world.
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Affiliation(s)
- Ana Luísa Tomás
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal.,UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Miguel P de Almeida
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Fernando Cardoso
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Mafalda Pinto
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Eulália Pereira
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Ricardo Franco
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Olga Matos
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa, Lisbon, Portugal
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Pérez FJ, Iturra PA, Ponce CA, Magne F, Garcia-Angulo V, Vargas SL. Niflumic Acid Reverses Airway Mucus Excess and Improves Survival in the Rat Model of Steroid-Induced Pneumocystis Pneumonia. Front Microbiol 2019; 10:1522. [PMID: 31333624 PMCID: PMC6624676 DOI: 10.3389/fmicb.2019.01522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/18/2019] [Indexed: 01/08/2023] Open
Abstract
Although the role of adaptive immunity in fighting Pneumocystis infection is well known, the role of the innate, airway epithelium, responses remains largely unexplored. The concerted interaction of innate and adaptive responses is essential to successfully eradicate infection. Increased expression of goblet-cell-derived CLCA1 protein plus excess mucus in infant autopsy lungs and in murine models of primary Pneumocystis infection alert of innate immune system immunopathology associated to Pneumocystis infection. Nonetheless, whether blocking mucus-associated innate immune pathways decreases Pneumocystis-related immunopathology is unknown. Furthermore, current treatment of Pneumocystis pneumonia (PcP) relying on anti-Pneumocystis drugs plus steroids is not ideal because removes cellular immune responses against the fungal pathogen. In this study, we used the steroid-induced rat model of PcP to evaluate inflammation and mucus progression, and tested the effect of niflumic acid (NFA), a fenamate-type drug with potent CLCA1 blocker activity, in decreasing Pneumocystis-associated immunopathology. In this model, animals acquire Pneumocystis spontaneously and pneumonia develops owing to the steroids-induced immunodeficiency. Steroids led to decreased animal weight evidencing severe immunosuppression and to significant Pneumocystis-associated pulmonary edema as evidenced by wet-to-dry lung ratios that doubled those of uninfected animals. Inflammatory cuffing infiltrates were noticed first around lung blood vessels followed by bronchi, and both increased progressively. Similarly, airway epithelial and lumen mucus progressively increased. This occurred in parallel to increasing levels of MUC5AC and mCLCA3, the murine homolog of hCLCA1. Administration of NFA caused a significant decrease in total mucus, MUC5AC and mCLCA3 and also, in Pneumocystis-associated inflammation. Most relevant, NFA treatment improved survival at 8 weeks of steroids. Results suggest an important role of innate immune responses in immunopathology of steroid-induced PcP. They warrant evaluation of CLCA1 blockers as adjunctive therapy in this condition and describe a simple model to evaluate therapeutic interventions for steroid resistant mucus, a common condition in patients with chronic lung disease like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.
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Affiliation(s)
- Francisco J Pérez
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Pablo A Iturra
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Carolina A Ponce
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Fabien Magne
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Víctor Garcia-Angulo
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio L Vargas
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
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