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Sepúlveda VE, Goldman WE, Matute DR. Genotypic diversity, virulence, and molecular genetic tools in Histoplasma. Microbiol Mol Biol Rev 2024; 88:e0007623. [PMID: 38819148 PMCID: PMC11332355 DOI: 10.1128/mmbr.00076-23] [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] [Indexed: 06/01/2024] Open
Abstract
SUMMARYHistoplasmosis is arguably the most common fungal respiratory infection worldwide, with hundreds of thousands of new infections occurring annually in the United States alone. The infection can progress in the lung or disseminate to visceral organs and can be difficult to treat with antifungal drugs. Histoplasma, the causative agent of the disease, is a pathogenic fungus that causes life-threatening lung infections and is globally distributed. The fungus has the ability to germinate from conidia into either hyphal (mold) or yeast form, depending on the environmental temperature. This transition also regulates virulence. Histoplasma and histoplasmosis have been classified as being of emergent importance, and in 2022, the World Health Organization included Histoplasma as 1 of the 19 most concerning human fungal pathogens. In this review, we synthesize the current understanding of the ecological niche, evolutionary history, and virulence strategies of Histoplasma. We also describe general patterns of the symptomatology and epidemiology of histoplasmosis. We underscore areas where research is sorely needed and highlight research avenues that have been productive.
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Affiliation(s)
- Victoria E. Sepúlveda
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - William E. Goldman
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Daniel R. Matute
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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2
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Boucher MJ, Madhani HD. Convergent evolution of innate immune-modulating effectors in invasive fungal pathogens. Trends Microbiol 2024; 32:435-447. [PMID: 37985333 DOI: 10.1016/j.tim.2023.10.011] [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: 09/29/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023]
Abstract
Invasive fungal infections pose a major threat to human health. Bacterial and protozoan pathogens secrete protein effectors that overcome innate immune barriers to promote microbial colonization, yet few such molecules have been identified in human fungal pathogens. Recent studies have begun to reveal these long-sought effectors and have illuminated how they subvert key cellular pathways, including apoptosis, myeloid cell polarization, Toll-like receptor signaling, and phagosome action. Thus, despite lacking the specialized secretion systems of bacteria and parasites, it is increasingly clear that fungi independently evolved effectors targeting pathways often subverted by other classes of pathogens. These findings demonstrate the remarkable power of convergent evolution to enable diverse microbes to infect humans while also setting the stage for detailed dissection of fungal disease mechanisms.
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Affiliation(s)
- Michael J Boucher
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hiten D Madhani
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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3
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da Silva AR, Herrera HM, de Oliveira CE, Torres JM, Ferreira AMR, Leite JDS, Menezes RC, Martinez ÉV, de Oliveira GMDS, Santos FM, de Andrade GB. The relationships among Leishmania infantum and phyllostomid bats assessed by histopathological and molecular assays. Int J Parasitol Parasites Wildl 2024; 23:100904. [PMID: 38261956 PMCID: PMC10797179 DOI: 10.1016/j.ijppaw.2023.100904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/25/2024]
Abstract
Bats have been reported as reservoir host of Leishmania spp. worldwide, mostly by molecular detection. However, it is still unclear whether bats act as reservoirs of Leishmania infantum to sandflies vectors. In this sense, the investigation of amastigotes forms in the target organs, and the characterization of their associated inflammation, may help to clarify the epidemiological importance of bats in endemic areas for leishmaniasis. The aim of this work was to investigate the host-parasite relationships under microscopic evaluation and predict the epidemiological role of two phyllostomid bats species naturally infected by L. infantum in an endemic area for human leishmaniasis. Fragments of skin, liver and spleen of L. infantum positive and negative bats (Artibeus planirostris and Carollia perspicillata) by qPCR, were studied by histological and immunohistochemical techniques. Both groups, positive and negative, did not show differences in the histopathological study, presenting only discrete tissue changes. Liver and skin showed mild inflammatory reactions. Findings on spleen consisted of reactivity of the lymphoid follicles, expressive presence of apoptotic cells and macrophages containing abundant phagocytic cells debris. We did not find amastigote forms in tissues by histological and IHC techniques in positive qPCR bats. Our results allow us to hypothesize that phyllostomid bats seem to have an important role in reducing the risk of transmission, possibly acting as dead-end host.
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Affiliation(s)
- Alanderson Rodrigues da Silva
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Biotecnologia, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Heitor Miraglia Herrera
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Biotecnologia, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Ciências Ambientais e Sustentabilidade Agropecuária, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Carina Elisei de Oliveira
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Biotecnologia, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Ciências Ambientais e Sustentabilidade Agropecuária, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
- LAMP LAB - LAMP Diagnostico LTDA– Av. Tamandaré, 6000, Jardim Seminário, 79117-900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Jaire Marinho Torres
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Biotecnologia, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Ana Maria Reis Ferreira
- Universidade Federal Fluminense, Departamento de Patologia e Clínica Veterinária, Faculdade de Veterinária, Rua Vital Brazil, 64, Niterói, Rio de Janeiro, Brazil
| | - Juliana da Silva Leite
- Universidade Federal Fluminense, Departamento de Patologia e Clínica Veterinária, Faculdade de Veterinária, Rua Vital Brazil, 64, Niterói, Rio de Janeiro, Brazil
| | - Rodrigo Caldas Menezes
- Fundação Oswaldo Cruz, Laboratório de Pesquisa Clínica em Dermatozoonoses em Animais Domésticos, Av. Brasil, 4036, Sala 119, Manguinhos, Brazil
- Instituto Nacional de Infectologia Evandro Chagas, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Érica Verneque Martinez
- Universidade Católica Dom Bosco, Programa Institucional de Bolsas de Iniciação Científica, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Gabrielly Moreira dos Santos de Oliveira
- Universidade Católica Dom Bosco, Programa Institucional de Bolsas de Iniciação Científica, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Filipe Martins Santos
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Ciências Ambientais e Sustentabilidade Agropecuária, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
- LAMP LAB - LAMP Diagnostico LTDA– Av. Tamandaré, 6000, Jardim Seminário, 79117-900, Campo Grande, Mato Grosso do Sul, Brazil
| | - Gisele Braziliano de Andrade
- Universidade Católica Dom Bosco, Programa de Pós-graduação em Ciências Ambientais e Sustentabilidade Agropecuária, Av. Tamandaré, 6000, CEP: 79117900, Campo Grande, Mato Grosso do Sul, Brazil
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Torres JM, de Oliveira CE, Santos FM, Sano NY, Martinez ÉV, Alves FM, Tavares LER, Roque ALR, Jansen AM, Herrera HM. Trypanosomatid diversity in a bat community of an urban area in Campo Grande, Mato Grosso do Sul, Brazil. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 118:105563. [PMID: 38301855 DOI: 10.1016/j.meegid.2024.105563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/14/2023] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
Bats have a long evolutionary history with trypanosomatids, but the role of these flying mammals on parasite transmission cycles in urban areas, especially for Trypanosoma and Leishmania species, remains poorly known. The objective of this study was to evaluate the species richness of trypanosomatids parasitizing a bat community in Campo Grande (CG), a state capital within the Cerrado of the Brazilian Midwest. We evaluated 237 bats of 13 species by means of hemoculture and molecular detection in spleen samples. The bat community of CG appears to participate in the transmission cycles of various species of trypanosomatids. We report an overall trypanosomatid detection rate of 34.2% (n = 81), involving 11 out of 13 sampled bat species. We identified six species of trypanosomatids from 61 bats by analyzing SSU rRNA and/or kDNA: Trypanosoma cruzi DTU TcI, T. c. marinkellei, T. dionisii, Leishmania infantum, L. amazonensis, and T. janseni, with this latter being detected by hemoculture for the first time in a bat species. We also detected a Molecular Operational Taxonomic Unit, Trypanosoma sp. DID, in the phyllostomids Glossophaga soricina and Platyrrhinus lineatus. The highest trypanosomatid richness was observed for Sturnira lilium, which hosted three species: L. infantum, T. dionisii and T. janseni. Given that visceral leishmaniasis is endemic in CG, special focus should be placed on L. infantum. Moreover, L. amazonensis and T. cruzi warrant attention, since these are zoonotic parasites responsible for human cases of tegumentary leishmaniasis and Chagas disease, respectively. In this respect, we discuss how bat communities may influence the Leishmania spp. transmission in endemic areas.
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Affiliation(s)
- Jaire Marinho Torres
- Universidade Católica Dom Bosco, Av. Tamandaré, 6000 - Jardim Seminário, Campo Grande, MS, Brazil
| | | | - Filipe Martins Santos
- Universidade Católica Dom Bosco, Av. Tamandaré, 6000 - Jardim Seminário, Campo Grande, MS, Brazil
| | - Nayara Yoshie Sano
- Universidade Católica Dom Bosco, Av. Tamandaré, 6000 - Jardim Seminário, Campo Grande, MS, Brazil
| | - Érica Verneque Martinez
- Universidade Federal de Mato Grosso do Sul, Cidade Universitária, Av. Costa e Silva s/n - Pioneiros, Campo Grande, MS, Brazil
| | - Fernanda Moreira Alves
- Laboratório de Biologia de Tripanossomatídeos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil, Manguinhos Rio de Janeiro 4365, RJ, Brazil
| | - Luiz Eduardo Roland Tavares
- Universidade Federal de Mato Grosso do Sul, Cidade Universitária, Av. Costa e Silva s/n - Pioneiros, Campo Grande, MS, Brazil
| | - André Luiz Rodrigues Roque
- Laboratório de Biologia de Tripanossomatídeos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil, Manguinhos Rio de Janeiro 4365, RJ, Brazil
| | - Ana Maria Jansen
- Universidade Católica Dom Bosco, Av. Tamandaré, 6000 - Jardim Seminário, Campo Grande, MS, Brazil; Laboratório de Biologia de Tripanossomatídeos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil, Manguinhos Rio de Janeiro 4365, RJ, Brazil
| | - Heitor Miraglia Herrera
- Universidade Católica Dom Bosco, Av. Tamandaré, 6000 - Jardim Seminário, Campo Grande, MS, Brazil
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Onwusereaka CO, Jalaludin J, Oluchi SE, Poh Choo VC. New generation sequencing: molecular approaches for the detection and monitoring of bioaerosols in an indoor environment: a systematic review. REVIEWS ON ENVIRONMENTAL HEALTH 2024; 0:reveh-2023-0004. [PMID: 38214730 DOI: 10.1515/reveh-2023-0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 12/14/2023] [Indexed: 01/13/2024]
Abstract
INTRODUCTION The exposure of occupants to indoor air pollutants has increased in recent decades. The aim of this review is to discuss an overview of new approaches that are used to study fungal aerosols. Thus, this motivation was to compensate the gaps caused by the use of only traditional approaches in the study of fungal exposure. CONTENT The search involved various databases such as; Science Direct, PubMed, SAGE, Springer Link, EBCOHOST, MEDLINE, CINAHL, Cochrane library, Web of Science and Wiley Online Library. It was limited to full text research articles that reported the use of non-viable method in assessing bioaerosol, written in English Language, full text publications and published from year 2015-2022. SUMMARY AND OUTLOOK A total of 15 articles met the inclusion criteria and was included in this review. The use of next-generation sequencing, which is more commonly referred to as high-throughput sequencing (HTS) or molecular methods in microbial studies is based on the detection of genetic material of organisms present in a given sample. Applying these methods to different environments permitted the identification of the microorganisms present, and a better comprehension of the environmental impacts and ecological roles of microbial communities. Based on the reviewed articles, there is evidence that dust samples harbour a high diversity of human-associated bacteria and fungi. Molecular methods such as next generation sequencing are reliable tools for identifying and tracking the bacterial and fungal diversity in dust samples using 18S metagenomics approach.
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Affiliation(s)
- Cynthia Oluchi Onwusereaka
- Department of Environmental and Occupational Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia Serdang, Selangor, Malaysia
| | - Juliana Jalaludin
- Department of Environmental and Occupational Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia Serdang, Selangor, Malaysia
| | - Sampson Emilia Oluchi
- Department of Community Health, Faculty of Medicine and Health Science, Universiti Putra Malaysia Serdang, Selangor, Malaysia
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Li X, Chen Z, Ye W, Yu J, Zhang X, Li Y, Niu Y, Ran S, Wang S, Luo Z, Zhao J, Hao Y, Zong J, Xia C, Xia J, Wu J. High-throughput CRISPR technology: a novel horizon for solid organ transplantation. Front Immunol 2024; 14:1295523. [PMID: 38239344 PMCID: PMC10794540 DOI: 10.3389/fimmu.2023.1295523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/12/2023] [Indexed: 01/22/2024] Open
Abstract
Organ transplantation is the gold standard therapy for end-stage organ failure. However, the shortage of available grafts and long-term graft dysfunction remain the primary barriers to organ transplantation. Exploring approaches to solve these issues is urgent, and CRISPR/Cas9-based transcriptome editing provides one potential solution. Furthermore, combining CRISPR/Cas9-based gene editing with an ex vivo organ perfusion system would enable pre-implantation transcriptome editing of grafts. How to determine effective intervention targets becomes a new problem. Fortunately, the advent of high-throughput CRISPR screening has dramatically accelerated the effective targets. This review summarizes the current advancements, utilization, and workflow of CRISPR screening in various immune and non-immune cells. It also discusses the ongoing applications of CRISPR/Cas-based gene editing in transplantation and the prospective applications of CRISPR screening in solid organ transplantation.
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Affiliation(s)
- Xiaohan Li
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhang Chen
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weicong Ye
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jizhang Yu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Zhang
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Li
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuqing Niu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuan Ran
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Song Wang
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zilong Luo
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiulu Zhao
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanglin Hao
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junjie Zong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chengkun Xia
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiahong Xia
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, National Health Commission (NHC) Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Jie Wu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, National Health Commission (NHC) Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
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Rappleye CA. Targeted gene deletions in the dimorphic fungal pathogen Histoplasma using an optimized episomal CRISPR/Cas9 system. mSphere 2023; 8:e0017823. [PMID: 37389430 PMCID: PMC10449496 DOI: 10.1128/msphere.00178-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 05/22/2023] [Indexed: 07/01/2023] Open
Abstract
The rapid development of CRISPR/CRISPR-associated (Cas) systems has revolutionized the ability to produce genetic mutations in a desired locus, particularly in organisms with low rates of homologous recombination. Histoplasma is an important respiratory and systemic fungal pathogen that has few reverse genetic options. We describe an optimized CRISPR/Cas system for the efficient generation of mutations in desired genes. The limited requirements for CRISPR/Cas, namely a gene-targeting guide RNA (gRNA) and expression of a Cas endonuclease, enabled both the gRNA and the Streptococcus pyogenes Cas9 gene to be expressed from a single episomal vector. The gRNAs are expressed from a strong Pol(II) promoter, a critical parameter for increasing the recovery of mutated genes, and processed into the mature gRNA by ribozymes in the mRNA. Expression of dual-tandem gRNAs facilitates the generation of gene deletions at a good frequency which can be detected by PCR-based screening of pooled isolates resulting in the isolation of marker-less deletion mutants. The CRISPR/Cas system is encoded on an episomal telomeric vector facilitating curing strains of the CRISPR/Cas vector upon generation of the mutant. We demonstrate the successful application of this CRISPR/Cas system in diverse Histoplasma species and applicable for multiple genes. The optimized system shows promise for accelerating reverse genetic studies in Histoplasma spp. IMPORTANCE The ability to eliminate gene product functions is central to understanding molecular mechanisms. In the fungal pathogen Histoplasma, methods to inactivate or deplete gene products are inefficient, which hampers progress in defining Histoplasma's virulence mechanisms. We describe an efficient CRISPR/Cas-based system for generating gene deletions in Histoplasma and show its validation on multiple genes with selectable and non-selectable phenotypes.
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Affiliation(s)
- Chad A. Rappleye
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
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Assa D, Voorhies M, Sil A. Chemical stimuli override a temperature-dependent morphological program by reprogramming the transcriptome of a fungal pathogen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.21.537729. [PMID: 37131633 PMCID: PMC10153268 DOI: 10.1101/2023.04.21.537729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The human fungal pathogen Histoplasma changes its morphology in response to temperature. At 37°C it grows as a budding yeast whereas at room temperature it transitions to hyphal growth. Prior work has demonstrated that 15-20% of transcripts are temperature-regulated, and that transcription factors Ryp1-4 are necessary to establish yeast growth. However, little is known about transcriptional regulators of the hyphal program. To identify TFs that regulate filamentation, we utilize chemical inducers of hyphal growth. We show that addition of cAMP analogs or an inhibitor of cAMP breakdown overrides yeast morphology, yielding inappropriate hyphal growth at 37°C. Additionally, butyrate supplementation triggers hyphal growth at 37°C. Transcriptional profiling of cultures filamenting in response to cAMP or butyrate reveals that a limited set of genes respond to cAMP while butyrate dysregulates a larger set. Comparison of these profiles to previous temperature- or morphology-regulated gene sets identifies a small set of morphology-specific transcripts. This set contains 9 TFs of which we characterized three, STU1 , FBC1 , and PAC2 , whose orthologs regulate development in other fungi. We found that each of these TFs is individually dispensable for room-temperature (RT) induced filamentation but each is required for other aspects of RT development. FBC1 and PAC2 , but not STU1 , are necessary for filamentation in response to cAMP at 37°C. Ectopic expression of each of these TFs is sufficient to induce filamentation at 37°C. Finally, PAC2 induction of filamentation at 37°C is dependent on STU1 , suggesting these TFs form a regulatory circuit that, when activated at RT, promotes the hyphal program. Importance Fungal illnesses pose a significant disease burden. However, the regulatory circuits that govern the development and virulence of fungi remain largely unknown. This study utilizes chemicals that can override the normal growth morphology of the human pathogen Histoplasma . Using transcriptomic approaches, we identify novel regulators of hyphal morphology and refine our understanding of the transcriptional circuits governing morphology in Histoplasma .
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Brown AJP. Fungal resilience and host-pathogen interactions: Future perspectives and opportunities. Parasite Immunol 2023; 45:e12946. [PMID: 35962618 PMCID: PMC10078341 DOI: 10.1111/pim.12946] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 01/31/2023]
Abstract
We are constantly exposed to the threat of fungal infection. The outcome-clearance, commensalism or infection-depends largely on the ability of our innate immune defences to clear infecting fungal cells versus the success of the fungus in mounting compensatory adaptive responses. As each seeks to gain advantage during these skirmishes, the interactions between host and fungal pathogen are complex and dynamic. Nevertheless, simply compromising the physiological robustness of fungal pathogens reduces their ability to evade antifungal immunity, their virulence, and their tolerance against antifungal therapy. In this article I argue that this physiological robustness is based on a 'Resilience Network' which mechanistically links and controls fungal growth, metabolism, stress resistance and drug tolerance. The elasticity of this network probably underlies the phenotypic variability of fungal isolates and the heterogeneity of individual cells within clonal populations. Consequently, I suggest that the definition of the fungal Resilience Network represents an important goal for the future which offers the clear potential to reveal drug targets that compromise drug tolerance and synergise with current antifungal therapies.
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Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK
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10
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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: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [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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Cohen A, Jeng EE, Voorhies M, Symington J, Ali N, Rodriguez RA, Bassik MC, Sil A. Genome-scale CRISPR screening reveals that C3aR signaling is critical for rapid capture of fungi by macrophages. PLoS Pathog 2022; 18:e1010237. [PMID: 36174103 PMCID: PMC9578593 DOI: 10.1371/journal.ppat.1010237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 10/18/2022] [Accepted: 07/13/2022] [Indexed: 11/18/2022] Open
Abstract
The fungal pathogen Histoplasma capsulatum (Hc) invades, replicates within, and destroys macrophages. To interrogate the molecular mechanisms underlying this interaction, we conducted a host-directed CRISPR-Cas9 screen and identified 361 genes that modify macrophage susceptibility to Hc infection, greatly expanding our understanding of host gene networks targeted by Hc. We identified pathways that have not been previously implicated in Hc interaction with macrophages, including the ragulator complex (involved in nutrient stress sensing), glycosylation enzymes, protein degradation machinery, mitochondrial respiration genes, solute transporters, and the ER membrane complex (EMC). The highest scoring protective hits included the complement C3a receptor (C3aR), a G-protein coupled receptor (GPCR) that recognizes the complement fragment C3a. Although it is known that complement components react with the fungal surface, leading to opsonization and release of small peptide fragments such as C3a, a role for C3aR in macrophage interactions with fungi has not been elucidated. We demonstrated that whereas C3aR is dispensable for macrophage phagocytosis of bacteria and latex beads, it is critical for optimal macrophage capture of pathogenic fungi, including Hc, the ubiquitous fungal pathogen Candida albicans, and the causative agent of Valley Fever Coccidioides posadasii. We showed that C3aR localizes to the early phagosome during Hc infection where it coordinates the formation of actin-rich membrane protrusions that promote Hc capture. We also showed that the EMC promotes surface expression of C3aR, likely explaining its identification in our screen. Taken together, our results provide new insight into host processes that affect Hc-macrophage interactions and uncover a novel and specific role for C3aR in macrophage recognition of fungi.
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Affiliation(s)
- Allison Cohen
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
| | - Edwin E. Jeng
- Stanford University, Department of Genetics, Palo Alto, California, United States of America
| | - Mark Voorhies
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
| | - Jane Symington
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
| | - Nebat Ali
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
| | - Rosa A. Rodriguez
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
| | - Michael C. Bassik
- Stanford University, Department of Genetics, Palo Alto, California, United States of America
| | - Anita Sil
- University of California San Francisco, Department of Microbiology and Immunology, San Francisco, California, United States of America
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12
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Azimova D, Herrera N, Duvenage L, Voorhies M, Rodriguez RA, English BC, Hoving JC, Rosenberg O, Sil A. Cbp1, a fungal virulence factor under positive selection, forms an effector complex that drives macrophage lysis. PLoS Pathog 2022; 18:e1010417. [PMID: 35731824 PMCID: PMC9255746 DOI: 10.1371/journal.ppat.1010417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/05/2022] [Accepted: 03/07/2022] [Indexed: 12/03/2022] Open
Abstract
Intracellular pathogens secrete effectors to manipulate their host cells. Histoplasma capsulatum (Hc) is a fungal intracellular pathogen of humans that grows in a yeast form in the host. Hc yeasts are phagocytosed by macrophages, where fungal intracellular replication precedes macrophage lysis. The most abundant virulence factor secreted by Hc yeast cells is Calcium Binding Protein 1 (Cbp1), which is absolutely required for macrophage lysis. Here we take an evolutionary, structural, and cell biological approach to understand Cbp1 function. We find that Cbp1 is present only in the genomes of closely related dimorphic fungal species of the Ajellomycetaceae family that lead primarily intracellular lifestyles in their mammalian hosts (Histoplasma, Paracoccidioides, and Emergomyces), but not conserved in the extracellular fungal pathogen Blastomyces dermatitidis. We observe a high rate of fixation of non-synonymous substitutions in the Cbp1 coding sequences, indicating that Cbp1 is under positive selection. We determine the de novo structures of Hc H88 Cbp1 and the Paracoccidioides americana (Pb03) Cbp1, revealing a novel "binocular" fold consisting of a helical dimer arrangement wherein two helices from each monomer contribute to a four-helix bundle. In contrast to Pb03 Cbp1, we show that Emergomyces Cbp1 orthologs are unable to stimulate macrophage lysis when expressed in the Hc cbp1 mutant. Consistent with this result, we find that wild-type Emergomyces africanus yeast are able to grow within primary macrophages but are incapable of lysing them. Finally, we use subcellular fractionation of infected macrophages and indirect immunofluorescence to show that Cbp1 localizes to the macrophage cytosol during Hc infection, making this the first instance of a phagosomal human fungal pathogen directing an effector into the cytosol of the host cell. We additionally show that Cbp1 forms a complex with Yps-3, another known Hc virulence factor that accesses the cytosol. Taken together, these data imply that Cbp1 is a fungal virulence factor under positive selection that localizes to the cytosol to trigger host cell lysis.
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Affiliation(s)
- Dinara Azimova
- University of California San Francisco, San Francisco, California, United States of America
| | - Nadia Herrera
- University of California San Francisco, San Francisco, California, United States of America
| | - Lucian Duvenage
- AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Mark Voorhies
- University of California San Francisco, San Francisco, California, United States of America
| | - Rosa A. Rodriguez
- University of California San Francisco, San Francisco, California, United States of America
| | - Bevin C. English
- University of California Davis, Davis, California, United States of America
| | - Jennifer C. Hoving
- AFRICA Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Oren Rosenberg
- University of California San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- University of California San Francisco, San Francisco, California, United States of America
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13
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Linhart P, Bandouchova H, Zukal J, Votýpka J, Baláž V, Heger T, Kalocsanyiova V, Kubickova A, Nemcova M, Sedlackova J, Seidlova V, Veitova L, Vlaschenko A, Divinova R, Pikula J. Blood Parasites and Health Status of Hibernating and Non-Hibernating Noctule Bats (Nyctalus noctula). Microorganisms 2022; 10:microorganisms10051028. [PMID: 35630470 PMCID: PMC9143927 DOI: 10.3390/microorganisms10051028] [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: 03/31/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/16/2022] Open
Abstract
Co-existence of bats with a wide range of infectious agents relates to their co-evolutionary history and specific physiology. Here, we examined blood samples collected during hibernation and the post-hibernation period to assess the influence of trypanosomes and babesias on the health status of 50 Noctule bats (Nyctalus noctula) using nested PCR. The impact of blood parasites on health was assessed by analysis of haematology and blood chemistry parameters in 21 bats. Prevalence of trypanosomes (Trypanosoma dionisii and T. vespertilionis) and babesia (Babesia vesperuginis) was 44% and 8%, respectively. Analysis of blood parameters indicated impact of babesia on acid–base balance. Blood chemistry parameters showed a significant decrease in total dissolved carbon dioxide and bicarbonate, increased anion gap, and no change in blood pH, suggesting compensated metabolic acidosis. Adverse effects of babesia were only apparent in hibernating bats. Our results suggest differences in the pathogenicity of trypanosomes and babesia in bats. While trypanosomes in general had no significant impact on the health status, we observed alterations in the blood acid–base balance in Babesia-infected bats during hibernation. Despite being infected, Babesia-positive bats survived hibernation without showing any clinical signs.
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Affiliation(s)
- Petr Linhart
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
- Department of Animal Protection and Welfare and Veterinary Public Health, University of Veterinary Sciences, 61242 Brno, Czech Republic
| | - Hana Bandouchova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
- Correspondence: ; Tel.: +420-541-562-653
| | - Jan Zukal
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, 60365 Brno, Czech Republic;
- Department of Botany and Zoology, Masaryk University, 61137 Brno, Czech Republic;
| | - Jan Votýpka
- Department of Parasitology, Faculty of Science, Charles University, 12800 Prague, Czech Republic;
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005 České Budějovice, Czech Republic
| | - Vojtech Baláž
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Tomas Heger
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Vendula Kalocsanyiova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Aneta Kubickova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Monika Nemcova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Jana Sedlackova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Veronika Seidlova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Lucie Veitova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
| | - Anton Vlaschenko
- Bat Rehabilitation Center of Feldman Ecopark, Lisne, 62340 Kharkiv, Ukraine;
| | - Renata Divinova
- Department of Botany and Zoology, Masaryk University, 61137 Brno, Czech Republic;
| | - Jiri Pikula
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, University of Veterinary Sciences, 61242 Brno, Czech Republic; (P.L.); (V.B.); (T.H.); (V.K.); (A.K.); (M.N.); (J.S.); (V.S.); (L.V.); (J.P.)
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Chromosome-Level Genome Assembly of a Human Fungal Pathogen Reveals Synteny among Geographically Distinct Species. mBio 2022; 13:e0257421. [PMID: 35089059 PMCID: PMC8725592 DOI: 10.1128/mbio.02574-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Histoplasma capsulatum, a dimorphic fungal pathogen, is the most common cause of fungal respiratory infections in immunocompetent hosts. Histoplasma is endemic in the Ohio and Mississippi River Valleys in the United States and is also distributed worldwide. Previous studies have revealed at least eight clades, each specific to a geographic location: North American classes 1 and 2 (NAm 1 and NAm 2), Latin American groups A and B (LAm A and LAm B), Eurasian, Netherlands, Australian and African, and an additional distinct lineage (H81) comprised of Panamanian isolates. Previously assembled Histoplasma genomes are highly fragmented, with the highly repetitive G217B (NAm 2) strain, which has been used for most whole-genome-scale transcriptome studies, assembled into over 250 contigs. In this study, we set out to fully assemble the repeat regions and characterize the large-scale genome architecture of Histoplasma species. We resequenced five Histoplasma strains (WU24 [NAm 1], G217B [NAm 2], H88 [African], G186AR [Panama], and G184AR [Panama]) using Oxford Nanopore Technologies long-read sequencing technology. Here, we report chromosomal-level assemblies for all five strains, which exhibit extensive synteny among the geographically distant Histoplasma isolates. The new assemblies revealed that RYP2, a major regulator of morphology and virulence, is duplicated in G186AR. In addition, we mapped previously generated transcriptome data sets onto the newly assembled chromosomes. Our analyses revealed that the expression of transposons and transposon-embedded genes are upregulated in yeast phase compared to mycelial phase in the G217B and H88 strains. This study provides an important resource for fungal researchers and further highlights the importance of chromosomal-level assemblies in analyzing high-throughput data sets. IMPORTANCE Histoplasma species are dimorphic fungi causing significant morbidity and mortality worldwide. These fungi grow as mold in the soil and as budding yeast within the human host. Histoplasma can be isolated from soil in diverse regions, including North America, South America, Africa, and Europe. Phylogenetically distinct species of Histoplasma have been isolated and sequenced. However, for the commonly used strains, genome assemblies have been fragmented, leading to underutilization of genome-scale data. This study provides chromosome-level assemblies of the commonly used Histoplasma strains using long-read sequencing technology. Comparative analysis of these genomes shows largely conserved gene order within the chromosomes. Mapping existing transcriptome data on these new assemblies reveals clustering of transcriptionally coregulated genes. The results of this study highlight the importance of obtaining chromosome-level assemblies in understanding the biology of human fungal pathogens.
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Blancett LT, Runge KA, Reyes GM, Kennedy LA, Jackson SC, Scheuermann SE, Harmon MB, Williams JC, Shearer G. Deletion of the Stress Response Gene DDR48 from Histoplasma capsulatum Increases Sensitivity to Oxidative Stress, Increases Susceptibility to Antifungals, and Decreases Fitness in Macrophages. J Fungi (Basel) 2021; 7:981. [PMID: 34829268 PMCID: PMC8617954 DOI: 10.3390/jof7110981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 11/21/2022] Open
Abstract
The stress response gene DDR48 has been characterized in Saccharomyces cerevisiae and Candida albicans to be involved in combating various cellular stressors, from oxidative agents to antifungal compounds. Surprisingly, the biological function of DDR48 has yet to be identified, though it is likely an important part of the stress response. To gain insight into its function, we characterized DDR48 in the dimorphic fungal pathogen Histoplasma capsulatum. Transcriptional analyses showed preferential expression of DDR48 in the mycelial phase. Induction of DDR48 in Histoplasma yeasts developed after treatment with various cellular stress compounds. We generated a ddr48∆ deletion mutant to further characterize DDR48 function. Loss of DDR48 alters the transcriptional profile of the oxidative stress response and membrane synthesis pathways. Treatment with ROS or antifungal compounds reduced survival of ddr48∆ yeasts compared to controls, consistent with an aberrant cellular stress response. In addition, we infected RAW 264.7 macrophages with DDR48-expressing and ddr48∆ yeasts and observed a 50% decrease in recovery of ddr48∆ yeasts compared to wild-type yeasts. Loss of DDR48 function results in numerous negative effects in Histoplasma yeasts, highlighting its role as a key player in the global sensing and response to cellular stress by fungi.
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Affiliation(s)
- Logan T. Blancett
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kauri A. Runge
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- ThruPore Technologies, Inc., New Castle, DE 19720, USA
| | - Gabriella M. Reyes
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
| | - Lauren A. Kennedy
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Sydney C. Jackson
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
| | - Sarah E. Scheuermann
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
- High Containment Research Performance Core, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Mallory B. Harmon
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Jamease C. Williams
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
- Mississippi INBRE Research Scholars Program, Mississippi INBRE, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Glenmore Shearer
- Center for Molecular and Cellular Biology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA; (K.A.R.); (G.M.R.); (L.A.K.); (S.C.J.); (S.E.S.); (M.B.H.); (J.C.W.); (G.S.J.)
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16
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Marcos CM, de Oliveira HC, Assato PA, Castelli RF, Fusco-Almeida AM, Mendes-Giannini MJS. Drk1, a Dimorphism Histidine Kinase, Contributes to Morphology, Virulence, and Stress Adaptation in Paracoccidioides brasiliensis. J Fungi (Basel) 2021; 7:jof7100852. [PMID: 34682273 PMCID: PMC8539220 DOI: 10.3390/jof7100852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/23/2021] [Accepted: 09/27/2021] [Indexed: 10/25/2022] Open
Abstract
P. brasiliensis is a thermally dimorphic fungus belonging to Paracoccidioides complex, causative of a systemic, endemic mycosis limited to Latin American countries. Signal transduction pathways related to important aspects as surviving, proliferation according to the biological niches are linked to the fungal pathogenicity in many species, but its elucidation in P. brasiliensis remains poorly explored. As Drk1, a hybrid histidine kinase, plays regulators functions in other dimorphic fungi species, mainly in dimorphism and virulence, here we investigated its importance in P. brasilensis. We, therefore generated the respective recombinant protein, anti-PbDrk1 polyclonal antibody and a silenced strain. The Drk1 protein shows a random distribution including cell wall location that change its pattern during osmotic stress condition; moreover the P. brasiliensis treatment with anti-PbDrk1 antibody, which does not modify the fungus's viability, resulted in decreased virulence in G. mellonella model and reduced interaction with pneumocytes. Down-regulating PbDRK1 yielded phenotypic alterations such as yeast cells with more elongated morphology, virulence attenuation in G. mellonella infection model, lower amount of chitin content, increased resistance to osmotic and cell wall stresses, and also caspofungin, and finally increased sensitivity to itraconazole. These observations highlight the importance of PbDrk1 to P. brasiliensis virulence, stress adaptation, morphology, and cell wall organization, and therefore it an interesting target that could help develop new antifungals.
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Affiliation(s)
- Caroline Maria Marcos
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, Brazil; (C.M.M.); (H.C.d.O.); (P.A.A.); (A.M.F.-A.)
| | - Haroldo Cesar de Oliveira
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, Brazil; (C.M.M.); (H.C.d.O.); (P.A.A.); (A.M.F.-A.)
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba 81350-010, Brazil;
| | - Patrícia Akemi Assato
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, Brazil; (C.M.M.); (H.C.d.O.); (P.A.A.); (A.M.F.-A.)
- Laboratório Central de Multiusuários, Faculdade de Ciências Agronômicas, Campus Botucatu, UNESP—Universidade Estadual Paulista, São Paulo 18610-034, Brazil
| | - Rafael Fernando Castelli
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Curitiba 81350-010, Brazil;
- Programa de Pós-Graduação em Biologia Parasitária, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (Fiocruz), Rio de Janeiro 21040-360, Brazil
| | - Ana Marisa Fusco-Almeida
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, Brazil; (C.M.M.); (H.C.d.O.); (P.A.A.); (A.M.F.-A.)
| | - Maria José Soares Mendes-Giannini
- School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara 14800-903, Brazil; (C.M.M.); (H.C.d.O.); (P.A.A.); (A.M.F.-A.)
- Correspondence:
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Abstract
Histoplasma capsulatum is a member of a group of fungal pathogens called thermally dimorphic fungi, all of which respond to mammalian body temperature by converting from an environmental mold form into a parasitic host form that causes disease. Histoplasma is a primary fungal pathogen, meaning it is able to cause disease in healthy individuals. We are beginning to understand how host temperature is utilized as a key signal to facilitate growth in the parasitic yeast form and promote production of virulence factors. In recent years, multiple regulators of morphology and virulence have been identified in Histoplasma. Mutations in these regulators render the pathogen unable to convert to the parasitic yeast form. Additionally, several virulence factors have been characterized for their importance in in vivo survival and pathogenesis. These virulence factors and regulators can serve as molecular handles for the development of effective drugs and therapeutics to counter Histoplasma infection.
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Affiliation(s)
- Sinem Beyhan
- Department of Infectious Diseases, J. Craig Venter Institute , La Jolla , CA , USA
| | - Anita Sil
- Department of Microbiology and Immunology, University of California , San Francisco , CA , USA
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18
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Van Dyke MCC, Teixeira MM, Barker BM. Fantastic yeasts and where to find them: the hidden diversity of dimorphic fungal pathogens. Curr Opin Microbiol 2019; 52:55-63. [PMID: 31181385 PMCID: PMC11227906 DOI: 10.1016/j.mib.2019.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/02/2019] [Accepted: 05/03/2019] [Indexed: 11/29/2022]
Abstract
Dimorphic fungal pathogens are a significant cause of human disease worldwide. Notably, the dimorphic fungal pathogens within the order Onygenales are considered primary pathogens, causing disease in healthy hosts. Current changes in taxonomy are underway due to advances in molecular phylogenetics, population genetics, and new emerging dimorphic fungal pathogens causing human disease. In this review, we highlight evolutionary relationships of dimorphic fungal pathogens that cause human disease within the order Onygenales and provide rationale to support increased investment in studies understanding the evolutionary relationships of these pathogens to improve rapid diagnostics, help identify mechanisms of antifungal resistance, understand adaptation to human host, and factors associated with virulence.
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Affiliation(s)
| | - Marcus M Teixeira
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States; Faculty of Medicine, University of Brasília, Brasília-DF, Brazil
| | - Bridget M Barker
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States.
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19
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Naderer T, Fulcher MC. Targeting apoptosis pathways in infections. J Leukoc Biol 2019; 103:275-285. [PMID: 29372933 DOI: 10.1189/jlb.4mr0717-286r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/29/2017] [Accepted: 09/13/2017] [Indexed: 11/24/2022] Open
Abstract
The programmed cell death pathway of apoptosis is essential for mammalian development and immunity as it eliminates unwanted and dangerous cells. As part of the cellular immune response, apoptosis removes the replicative niche of intracellular pathogens and enables the resolution of infections. To subvert apoptosis, pathogens have evolved a diverse range of mechanisms. In some circumstances, however, pathogens express effector molecules that induce apoptotic cell death. In this review, we focus on selected host-pathogen interactions that affect apoptotic pathways. We discuss how pathogens control the fate of host cells and how this determines the outcome of infections. Finally, small molecule inhibitors that activate apoptosis in cancer cells can also induce apoptotic cell death of infected cells. This suggests that targeting host death factors to kill infected cells is a potential therapeutic option to treat infectious diseases.
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Affiliation(s)
- Thomas Naderer
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia
| | - Maria Cecilia Fulcher
- Biomedicine Discovery Institute and Department of Biochemistry & Molecular Biology, Monash University, Clayton, Australia
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20
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Zhang J, Miao Y, Rahimi MJ, Zhu H, Steindorff A, Schiessler S, Cai F, Pang G, Chenthamara K, Xu Y, Kubicek CP, Shen Q, Druzhinina IS. Guttation capsules containing hydrogen peroxide: an evolutionarily conserved NADPH oxidase gains a role in wars between related fungi. Environ Microbiol 2019; 21:2644-2658. [PMID: 30815928 PMCID: PMC6850483 DOI: 10.1111/1462-2920.14575] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 02/24/2019] [Accepted: 02/26/2019] [Indexed: 12/01/2022]
Abstract
When resources are limited, the hypocrealean fungus Trichoderma guizhouense can overgrow another hypocrealean fungus Fusarium oxysporum, cause sporadic cell death and arrest growth. A transcriptomic analysis of this interaction shows that T. guizhouense undergoes a succession of metabolic stresses while F. oxysporum responded relatively neutrally but used the constitutive expression of several toxin‐encoding genes as a protective strategy. Because of these toxins, T. guizhouense cannot approach it is potential host on the substrate surface and attacks F. oxysporum from above. The success of T. guizhouense is secured by the excessive production of hydrogen peroxide (H2O2), which is stored in microscopic bag‐like guttation droplets hanging on the contacting hyphae. The deletion of NADPH oxidase nox1 and its regulator, nor1 in T. guizhouense led to a substantial decrease in H2O2 formation with concomitant loss of antagonistic activity. We envision the role of NOX proteins in the antagonism of T. guizhouense as an example of metabolic exaptation evolved in this fungus because the primary function of these ancient proteins was probably not linked to interfungal relationships. In support of this, F. oxysporum showed almost no transcriptional response to T. guizhouense Δnox1 strain indicating the role of NOX/H2O2 in signalling and fungal communication.
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Affiliation(s)
- Jian Zhang
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China.,Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Youzhi Miao
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - Mohammad Javad Rahimi
- Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Hong Zhu
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - Andrei Steindorff
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, USA
| | - Sabine Schiessler
- Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Feng Cai
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China.,Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Guan Pang
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - Komal Chenthamara
- Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Yu Xu
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - Christian P Kubicek
- Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria.,Steinschoetelgasse 7,1100, Vienna, Austria
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China
| | - Irina S Druzhinina
- Jiangsu Provincial Key Lab of Organic Solid Waste Utilization, Nanjing Agricultural University, Nanjing, China.,Microbiology and Applied Genomics Group, Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
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21
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Mittal J, Ponce MG, Gendlina I, Nosanchuk JD. Histoplasma Capsulatum: Mechanisms for Pathogenesis. Curr Top Microbiol Immunol 2019; 422:157-191. [PMID: 30043340 PMCID: PMC7212190 DOI: 10.1007/82_2018_114] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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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22
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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: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [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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23
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Maxwell CS, Sepulveda VE, Turissini DA, Goldman WE, Matute DR. Recent admixture between species of the fungal pathogen Histoplasma. Evol Lett 2018; 2:210-220. [PMID: 30283677 PMCID: PMC6121842 DOI: 10.1002/evl3.59] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/03/2018] [Accepted: 05/08/2018] [Indexed: 12/30/2022] Open
Abstract
Hybridization between species of pathogens has the potential to speed evolution of virulence by providing the raw material for adaptation through introgression or by assembling new combinations of virulence traits. Fungal diseases are a source high morbidity, and remain difficult to treat. Yet the frequency of hybridization between fungal species has rarely been explored, and the functional role of introgressed alleles remains largely unknown. Histoplasma mississippiense and H. ohiense are sympatric throughout their range in North America and have distinct virulence strategies, making them an ideal system to examine the role introgression may play in fungal pathogens. We identified introgressed tracts in the genomes of a sample of H. mississippiense and H. ohiense isolates. We found strong evidence in each species for recent admixture, but introgressed alleles were present at low frequencies, suggesting that they were deleterious. Consistent with this, coding and regulatory sequences were strongly depleted within introgressed regions, whereas intergenic regions were enriched, indicating that functional introgressed alleles were frequently deleterious in their new genomic context. Surprisingly, we found only two isolates with substantial admixture: the H. mississippiense and H. ohiense genomic reference strains, WU24 and G217B, respectively. Our results show that recent admixture has occurred, that it is frequently deleterious and that conclusions based on studies of the H. mississippiense and H. ohiense type strains should be revisited with more representative samples from the genus.
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Affiliation(s)
- Colin S Maxwell
- Biology Department University of North Carolina Chapel Hill North Carolina 27599
| | - Victoria E Sepulveda
- Department of Microbiology and Immunology, School of Medicine University of North Carolina Chapel Hill North Carolina 27599
| | - David A Turissini
- Biology Department University of North Carolina Chapel Hill North Carolina 27599
| | - William E Goldman
- Department of Microbiology and Immunology, School of Medicine University of North Carolina Chapel Hill North Carolina 27599
| | - Daniel R Matute
- Biology Department University of North Carolina Chapel Hill North Carolina 27599
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24
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Kyrmizi I, Ferreira H, Carvalho A, Figueroa JAL, Zarmpas P, Cunha C, Akoumianaki T, Stylianou K, Deepe GS, Samonis G, Lacerda JF, Campos A, Kontoyiannis DP, Mihalopoulos N, Kwon-Chung KJ, El-Benna J, Valsecchi I, Beauvais A, Brakhage AA, Neves NM, Latge JP, Chamilos G. Calcium sequestration by fungal melanin inhibits calcium-calmodulin signalling to prevent LC3-associated phagocytosis. Nat Microbiol 2018; 3:791-803. [PMID: 29849062 DOI: 10.1038/s41564-018-0167-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 04/23/2018] [Indexed: 11/09/2022]
Abstract
LC3-associated phagocytosis (LAP) is a non-canonical autophagy pathway regulated by Rubicon, with an emerging role in immune homeostasis and antifungal host defence. Aspergillus cell wall melanin protects conidia (spores) from killing by phagocytes and promotes pathogenicity through blocking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent activation of LAP. However, the signalling regulating LAP upstream of Rubicon and the mechanism of melanin-induced inhibition of this pathway remain incompletely understood. Herein, we identify a Ca2+ signalling pathway that depends on intracellular Ca2+ sources from endoplasmic reticulum, endoplasmic reticulum-phagosome communication, Ca2+ release from phagosome lumen and calmodulin (CaM) recruitment, as a master regulator of Rubicon, the phagocyte NADPH oxidase NOX2 and other molecular components of LAP. Furthermore, we provide genetic evidence for the physiological importance of Ca2+-CaM signalling in aspergillosis. Finally, we demonstrate that Ca2+ sequestration by Aspergillus melanin inside the phagosome abrogates activation of Ca2+-CaM signalling to inhibit LAP. These findings reveal the important role of Ca2+-CaM signalling in antifungal immunity and identify an immunological function of Ca2+ binding by melanin pigments with broad physiological implications beyond fungal disease pathogenesis.
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Affiliation(s)
- Irene Kyrmizi
- Department of Medicine, University of Crete, Heraklion, Crete, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
| | - Helena Ferreira
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Guimarães, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Agostinho Carvalho
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Julio Alberto Landero Figueroa
- Department of Chemistry, University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, University of Cincinnati, Cincinnati, OH, USA
| | - Pavlos Zarmpas
- Department of Chemistry, University of Crete, Heraklion, Crete, Greece
| | - Cristina Cunha
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Tonia Akoumianaki
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Kostas Stylianou
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - George S Deepe
- Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - George Samonis
- Department of Medicine, University of Crete, Heraklion, Crete, Greece
| | - João F Lacerda
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Lisbon, Portugal.,Serviço de Hematologia e Transplantação de Medula, Hospital de Santa Maria, Lisbon, Portugal
| | - António Campos
- Serviço de Transplantação de Medula Óssea (STMO), Instituto Português de Oncologia do Porto, Porto, Portugal
| | - Dimitrios P Kontoyiannis
- Department of Infectious Diseases, The University of Texas, MD Anderson Cancer Center, Austin, TX, USA
| | | | - Kyung J Kwon-Chung
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Jamel El-Benna
- INSERM-U1149, CNRS-ERL8252, Centre de Recherche sur l'Inflammation, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, DHU FIRE, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | | | - Anne Beauvais
- Unité des Aspergillus, Institut Pasteur, Paris, France
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology (HKI) and Friedrich Schiller University, Jena, Germany
| | - Nuno M Neves
- 3B's Research Group - Biomaterials, Biodegradables and Biomimetics, Guimarães, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | | | - Georgios Chamilos
- Department of Medicine, University of Crete, Heraklion, Crete, Greece. .,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece.
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25
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Garfoot AL, Goughenour KD, Wüthrich M, Rajaram MVS, Schlesinger LS, Klein BS, Rappleye CA. O-Mannosylation of Proteins Enables Histoplasma Yeast Survival at Mammalian Body Temperatures. mBio 2018; 9:e02121-17. [PMID: 29295913 PMCID: PMC5750402 DOI: 10.1128/mbio.02121-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 01/30/2023] Open
Abstract
The ability to grow at mammalian body temperatures is critical for pathogen infection of humans. For the thermally dimorphic fungal pathogen Histoplasma capsulatum, elevated temperature is required for differentiation of mycelia or conidia into yeast cells, a step critical for invasion and replication within phagocytic immune cells. Posttranslational glycosylation of extracellular proteins characterizes factors produced by the pathogenic yeast cells but not those of avirulent mycelia, correlating glycosylation with infection. Histoplasma yeast cells lacking the Pmt1 and Pmt2 protein mannosyltransferases, which catalyze O-linked mannosylation of proteins, are severely attenuated during infection of mammalian hosts. Cells lacking Pmt2 have altered surface characteristics that increase recognition of yeast cells by the macrophage mannose receptor and reduce recognition by the β-glucan receptor Dectin-1. Despite these changes, yeast cells lacking these factors still associate with and survive within phagocytes. Depletion of macrophages or neutrophils in vivo does not recover the virulence of the mutant yeast cells. We show that yeast cells lacking Pmt functions are more sensitive to thermal stress in vitro and consequently are unable to productively infect mice, even in the absence of fever. Treatment of mice with cyclophosphamide reduces the normal core body temperature of mice, and this decrease is sufficient to restore the infectivity of O-mannosylation-deficient yeast cells. These findings demonstrate that O-mannosylation of proteins increases the thermotolerance of Histoplasma yeast cells, which facilitates infection of mammalian hosts.IMPORTANCE For dimorphic fungal pathogens, mammalian body temperature can have contrasting roles. Mammalian body temperature induces differentiation of the fungal pathogen Histoplasma capsulatum into a pathogenic state characterized by infection of host phagocytes. On the other hand, elevated temperatures represent a significant barrier to infection by many microbes. By functionally characterizing cells lacking O-linked mannosylation enzymes, we show that protein mannosylation confers thermotolerance on H. capsulatum, enabling infection of mammalian hosts.
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Affiliation(s)
- Andrew L Garfoot
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
| | | | - Marcel Wüthrich
- Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, USA
| | - Murugesan V S Rajaram
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, USA
| | - Larry S Schlesinger
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, USA
| | - Bruce S Klein
- Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, USA
- Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA
| | - Chad A Rappleye
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Department of Microbial Infection and Immunity, Center for Microbial Interface Biology, Ohio State University, Columbus, Ohio, USA
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26
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Shen Q, Rappleye CA. Differentiation of the fungus Histoplasma capsulatum into a pathogen of phagocytes. Curr Opin Microbiol 2017; 40:1-7. [PMID: 29096192 DOI: 10.1016/j.mib.2017.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/09/2017] [Indexed: 01/06/2023]
Abstract
Mammalian body temperature triggers differentiation of the fungal pathogen Histoplasma capsulatum into yeast cells. The Drk1 regulatory kinase and an interdependent network of Ryp transcription factors establish the yeast state. Beyond morphology, the differentiation-dependent expression program equips yeasts for invasion and survival within phagosomes. Yeast cells produce α-glucan and the Eng1 endoglucanase which hide yeasts from immune detection. Secretion of yeast phase-specific Sod3 and CatB detoxify phagocyte-derived reactive oxygen molecules. Histoplasma cells adapt to iron and zinc limitation in activated macrophages by production of siderophores and the Zrt2 transporter, respectively. Yeasts also respond to inflammation-associated hypoxia. Histoplasma pathogenicity thus relies on factors controlled by yeast differentiation as well as environment-dependent responses.
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Affiliation(s)
- Qian Shen
- Ohio State University, Columbus, OH 43210, USA
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27
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English BC, Van Prooyen N, Örd T, Örd T, Sil A. The transcription factor CHOP, an effector of the integrated stress response, is required for host sensitivity to the fungal intracellular pathogen Histoplasma capsulatum. PLoS Pathog 2017; 13:e1006589. [PMID: 28953979 PMCID: PMC5633207 DOI: 10.1371/journal.ppat.1006589] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 10/09/2017] [Accepted: 08/17/2017] [Indexed: 02/06/2023] Open
Abstract
The ability of intracellular pathogens to manipulate host-cell viability is critical to successful infection. Some pathogens promote host-cell survival to protect their replicative niche, whereas others trigger host-cell death to facilitate release and dissemination of the pathogen after intracellular replication has occurred. We previously showed that the intracellular fungal pathogen Histoplasma capsulatum (Hc) uses the secreted protein Cbp1 to actively induce apoptosis in macrophages; interestingly, cbp1 mutant strains are unable to kill macrophages and display severely reduced virulence in the mouse model of Hc infection. To elucidate the mechanism of Cbp1-induced host-cell death, we performed a comprehensive alanine scanning mutagenesis and identified all amino acid residues that are required for Cbp1 to trigger macrophage lysis. Here we demonstrate that Hc strains expressing lytic CBP1 alleles activate the integrated stress response (ISR) in infected macrophages, as indicated by an increase in eIF2α phosphorylation as well as induction of the transcription factor CHOP and the pseudokinase Tribbles 3 (TRIB3). In contrast, strains bearing a non-lytic allele of CBP1 fail to activate the ISR, whereas a partially lytic CBP1 allele triggers intermediate levels of activation. We further show that macrophages deficient for CHOP or TRIB3 are partially resistant to lysis during Hc infection, indicating that the ISR is critical for susceptibility to Hc-mediated cell death. Moreover, we show that CHOP-dependent macrophage lysis is critical for efficient spread of Hc infection to other macrophages. Notably, CHOP knockout mice display reduced macrophage apoptosis and diminished fungal burden and are markedly resistant to Hc infection. Together, these data indicate that Cbp1 is required for Hc to induce the ISR and mediate a CHOP-dependent virulence pathway in the host. Histoplasma capsulatum is the causative agent of histoplasmosis, a fungal infection that can be fatal in a wide range of mammalian hosts, including otherwise healthy, immunocompetent individuals. Histoplasma cells replicate to very high levels within host macrophages, eventually causing macrophage death and the release of live fungal cells. Here, we show that Histoplasma yeast use the secreted protein Cbp1 to activate a specific signaling pathway in the host cell to cause macrophage death during infection. Importantly, this signaling cascade is essential for pathogenesis, and mice deficient for a central component of this pathway are resistant to Histoplasma infection. Our study is the first demonstration that Histoplasma employs a secreted effector to alter host signaling pathways to promote virulence, and thus provides key insight into the pathogenesis strategies of this important human fungal pathogen.
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Affiliation(s)
- Bevin C. English
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Nancy Van Prooyen
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- FLX Bio, South San Francisco, California, United States of America
| | - Tiit Örd
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- Estonian Biocentre, Tartu, Estonia
| | | | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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28
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Idnurm A, Bailey AM, Cairns TC, Elliott CE, Foster GD, Ianiri G, Jeon J. A silver bullet in a golden age of functional genomics: the impact of Agrobacterium-mediated transformation of fungi. Fungal Biol Biotechnol 2017; 4:6. [PMID: 28955474 PMCID: PMC5615635 DOI: 10.1186/s40694-017-0035-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/18/2017] [Indexed: 11/10/2022] Open
Abstract
The implementation of Agrobacterium tumefaciens as a transformation tool revolutionized approaches to discover and understand gene functions in a large number of fungal species. A. tumefaciens mediated transformation (AtMT) is one of the most transformative technologies for research on fungi developed in the last 20 years, a development arguably only surpassed by the impact of genomics. AtMT has been widely applied in forward genetics, whereby generation of strain libraries using random T-DNA insertional mutagenesis, combined with phenotypic screening, has enabled the genetic basis of many processes to be elucidated. Alternatively, AtMT has been fundamental for reverse genetics, where mutant isolates are generated with targeted gene deletions or disruptions, enabling gene functional roles to be determined. When combined with concomitant advances in genomics, both forward and reverse approaches using AtMT have enabled complex fungal phenotypes to be dissected at the molecular and genetic level. Additionally, in several cases AtMT has paved the way for the development of new species to act as models for specific areas of fungal biology, particularly in plant pathogenic ascomycetes and in a number of basidiomycete species. Despite its impact, the implementation of AtMT has been uneven in the fungi. This review provides insight into the dynamics of expansion of new research tools into a large research community and across multiple organisms. As such, AtMT in the fungi, beyond the demonstrated and continuing power for gene discovery and as a facile transformation tool, provides a model to understand how other technologies that are just being pioneered, e.g. CRISPR/Cas, may play roles in fungi and other eukaryotic species.
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Affiliation(s)
- Alexander Idnurm
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Andy M. Bailey
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Timothy C. Cairns
- Department of Applied and Molecular Microbiology, Technische Universität Berlin, Berlin, Germany
| | - Candace E. Elliott
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010 Australia
| | - Gary D. Foster
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
| | - Junhyun Jeon
- College of Life and Applied Sciences, Yeungnam University, Gyeongsan, South Korea
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29
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Fungal Dimorphism and Virulence: Molecular Mechanisms for Temperature Adaptation, Immune Evasion, and In Vivo Survival. Mediators Inflamm 2017. [PMID: 28626345 PMCID: PMC5463121 DOI: 10.1155/2017/8491383] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The thermally dimorphic fungi are a unique group of fungi within the Ascomycota phylum that respond to shifts in temperature by converting between hyphae (22–25°C) and yeast (37°C). This morphologic switch, known as the phase transition, defines the biology and lifestyle of these fungi. The conversion to yeast within healthy and immunocompromised mammalian hosts is essential for virulence. In the yeast phase, the thermally dimorphic fungi upregulate genes involved with subverting host immune defenses. This review highlights the molecular mechanisms governing the phase transition and recent advances in how the phase transition promotes infection.
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30
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Kosmidis C, Denning DW. Opportunistic and Systemic Fungi. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00189-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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31
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Danhof HA, Vylkova S, Vesely EM, Ford AE, Gonzalez-Garay M, Lorenz MC. Robust Extracellular pH Modulation by Candida albicans during Growth in Carboxylic Acids. mBio 2016; 7:e01646-16. [PMID: 27935835 PMCID: PMC5111404 DOI: 10.1128/mbio.01646-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/24/2016] [Indexed: 12/25/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans thrives within diverse niches in the mammalian host. Among the adaptations that underlie this fitness is an ability to utilize a wide array of nutrients, especially sources of carbon that are disfavored by many other fungi; this contributes to its ability to survive interactions with the phagocytes that serve as key barriers against disseminated infections. We have reported that C. albicans generates ammonia as a byproduct of amino acid catabolism to neutralize the acidic phagolysosome and promote hyphal morphogenesis in a manner dependent on the Stp2 transcription factor. Here, we report that this species rapidly neutralizes acidic environments when utilizing carboxylic acids like pyruvate, α-ketoglutarate (αKG), or lactate as the primary carbon source. Unlike in cells growing in amino acid-rich medium, this does not result in ammonia release, does not induce hyphal differentiation, and is genetically distinct. While transcript profiling revealed significant similarities in gene expression in cells grown on either carboxylic or amino acids, genetic screens for mutants that fail to neutralize αKG medium identified a nonoverlapping set of genes, including CWT1, encoding a transcription factor responsive to cell wall and nitrosative stresses. Strains lacking CWT1 exhibit retarded αKG-mediated neutralization in vitro, exist in a more acidic phagolysosome, and are more susceptible to macrophage killing, while double cwt1Δ stp2Δ mutants are more impaired than either single mutant. Together, our observations indicate that C. albicans has evolved multiple ways to modulate the pH of host-relevant environments to promote its fitness as a pathogen. IMPORTANCE The fungal pathogen Candida albicans is a ubiquitous and usually benign constituent of the human microbial ecosystem. In individuals with weakened immune systems, this organism can cause potentially life-threatening infections and is one of the most common causes of hospital-acquired infections. Understanding the interactions between C. albicans and immune phagocytic cells, such as macrophages and neutrophils, will define the mechanisms of pathogenesis in this species. One such adaptation is an ability to make use of nonstandard nutrients that we predict are plentiful in certain niches within the host, including within these phagocytic cells. We show here that the metabolism of certain organic acids enables C. albicans to neutralize acidic environments, such as those within macrophages. This phenomenon is distinct in several significant ways from previous reports of similar processes, indicating that C. albicans has evolved multiple mechanisms to combat the harmful acidity of phagocytic cells.
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Affiliation(s)
- Heather A Danhof
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Slavena Vylkova
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Elisa M Vesely
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Amy E Ford
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Manuel Gonzalez-Garay
- The Brown Foundation Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Michael C Lorenz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
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Marcos CM, de Oliveira HC, de Melo WDCMA, da Silva JDF, Assato PA, Scorzoni L, Rossi SA, de Paula E Silva ACA, Mendes-Giannini MJS, Fusco-Almeida AM. Anti-Immune Strategies of Pathogenic Fungi. Front Cell Infect Microbiol 2016; 6:142. [PMID: 27896220 PMCID: PMC5108756 DOI: 10.3389/fcimb.2016.00142] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/13/2016] [Indexed: 12/24/2022] Open
Abstract
Pathogenic fungi have developed many strategies to evade the host immune system. Multiple escape mechanisms appear to function together to inhibit attack by the various stages of both the adaptive and the innate immune response. Thus, after entering the host, such pathogens fight to overcome the immune system to allow their survival, colonization and spread to different sites of infection. Consequently, the establishment of a successful infectious process is closely related to the ability of the pathogen to modulate attack by the immune system. Most strategies employed to subvert or exploit the immune system are shared among different species of fungi. In this review, we summarize the main strategies employed for immune evasion by some of the major pathogenic fungi.
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Affiliation(s)
- Caroline M Marcos
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Haroldo C de Oliveira
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Wanessa de Cássia M Antunes de Melo
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Julhiany de Fátima da Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Patrícia A Assato
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Liliana Scorzoni
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Suélen A Rossi
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana C A de Paula E Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Maria J S Mendes-Giannini
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana M Fusco-Almeida
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
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Crossley D, Naraharisetty V, Shearer G. The Mould-specific M46 gene is not essential for yeast-mould dimorphism in the pathogenic fungus Histoplasma capsulatum. Med Mycol 2016; 54:876-84. [PMID: 27335057 DOI: 10.1093/mmy/myw040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/15/2016] [Indexed: 11/12/2022] Open
Abstract
Histoplasma capsulatum (Hc) is the causative agent for the respiratory infection histoplasmosis. The fungus exists in the environment as a saprophytic multi-cellular mould. Spores are inhaled by mammals whereupon the organism will convert into the single-celled yeast morphotype resulting in infection. The shift to the yeast morphotype is required for pathogenesis. Most studies on dimorphism have examined yeast-phase-specific genes and few mould-phase-specific genes have been investigated. It is likely, that some mould-phase-specific genes must be downregulated for the yeast to form or upregulated for the mould to form. We isolated a strongly expressed mould-specific gene, M46, from an expression library enriched for mould upregulated genes in Hc strain G186AS. To determine if M46 is involved in dimorphism, M46 was ectopically expressed in yeast phase growing temperature, and an m46 knockout strain was created via allelic replacement. Ectopically expressing M46 in yeast, did not induce filamentous growth. Genomic disruption of M46 by allelic replacement did not alter the morphology of the mould as seen in bright field microscopy, scanning electron microscopy, and transmission electron microscopy. A growth curve study, revealed that M46 is not involved in maintaining the growth rate of cells. These findings indicate that the mould specific M46 gene is not necessary nor essential for dimorphism, maintaining the normal mould morphology, and growth rate of Histoplasma capsulatum.
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Affiliation(s)
- Davida Crossley
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Vani Naraharisetty
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
| | - Glenmore Shearer
- Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, USA
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Muñoz JF, Farrer RA, Desjardins CA, Gallo JE, Sykes S, Sakthikumar S, Misas E, Whiston EA, Bagagli E, Soares CMA, Teixeira MDM, Taylor JW, Clay OK, McEwen JG, Cuomo CA. Genome Diversity, Recombination, and Virulence across the Major Lineages of Paracoccidioides. mSphere 2016; 1:e00213-16. [PMID: 27704050 PMCID: PMC5040785 DOI: 10.1128/msphere.00213-16] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/06/2016] [Indexed: 12/29/2022] Open
Abstract
The Paracoccidioides genus includes two species of thermally dimorphic fungi that cause paracoccidioidomycosis, a neglected health-threatening human systemic mycosis endemic to Latin America. To examine the genome evolution and the diversity of Paracoccidioides spp., we conducted whole-genome sequencing of 31 isolates representing the phylogenetic, geographic, and ecological breadth of the genus. These samples included clinical, environmental and laboratory reference strains of the S1, PS2, PS3, and PS4 lineages of P. brasiliensis and also isolates of Paracoccidioides lutzii species. We completed the first annotated genome assemblies for the PS3 and PS4 lineages and found that gene order was highly conserved across the major lineages, with only a few chromosomal rearrangements. Comparing whole-genome assemblies of the major lineages with single-nucleotide polymorphisms (SNPs) predicted from the remaining 26 isolates, we identified a deep split of the S1 lineage into two clades we named S1a and S1b. We found evidence for greater genetic exchange between the S1b lineage and all other lineages; this may reflect the broad geographic range of S1b, which is often sympatric with the remaining, largely geographically isolated lineages. In addition, we found evidence of positive selection for the GP43 and PGA1 antigen genes and genes coding for other secreted proteins and proteases and lineage-specific loss-of-function mutations in cell wall and protease genes; these together may contribute to virulence and host immune response variation among natural isolates of Paracoccidioides spp. These insights into the recent evolutionary events highlight important differences between the lineages that could impact the distribution, pathogenicity, and ecology of Paracoccidioides. IMPORTANCE Characterization of genetic differences between lineages of the dimorphic human-pathogenic fungus Paracoccidioides can identify changes linked to important phenotypes and guide the development of new diagnostics and treatments. In this article, we compared genomes of 31 diverse isolates representing the major lineages of Paracoccidioides spp. and completed the first annotated genome sequences for the PS3 and PS4 lineages. We analyzed the population structure and characterized the genetic diversity among the lineages of Paracoccidioides, including a deep split of S1 into two lineages (S1a and S1b), and differentiated S1b, associated with most clinical cases, as the more highly recombining and diverse lineage. In addition, we found patterns of positive selection in surface proteins and secreted enzymes among the lineages, suggesting diversifying mechanisms of pathogenicity and adaptation across this species complex. These genetic differences suggest associations with the geographic range, pathogenicity, and ecological niches of Paracoccidioides lineages.
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Affiliation(s)
- José F. Muñoz
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Institute of Biology, Universidad de Antioquia, Medellín, Colombia
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Rhys A. Farrer
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | - Juan E. Gallo
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Doctoral Program in Biomedical Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Sean Sykes
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | - Elizabeth Misas
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Institute of Biology, Universidad de Antioquia, Medellín, Colombia
| | - Emily A. Whiston
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Eduardo Bagagli
- Instituto de Biociências, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | - Celia M. A. Soares
- Laboratório de Biología Molecular, Instituto de Ciências Biológicas, ICBII, Goiânia, Brazil
| | - Marcus de M. Teixeira
- Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil
- Division of Pathogen Genomics, Translational Genomics Research Institute North, Flagstaff, Arizona, USA
| | - John W. Taylor
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Oliver K. Clay
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Juan G. McEwen
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Medicine, Universidad de Antioquia, Medellín, Colombia
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Garfoot AL, Shen Q, Wüthrich M, Klein BS, Rappleye CA. The Eng1 β-Glucanase Enhances Histoplasma Virulence by Reducing β-Glucan Exposure. mBio 2016; 7:e01388-15. [PMID: 27094334 PMCID: PMC4850272 DOI: 10.1128/mbio.01388-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 03/18/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The fungal pathogen Histoplasma capsulatum parasitizes host phagocytes. To avoid antimicrobial immune responses, Histoplasma yeasts must minimize their detection by host receptors while simultaneously interacting with the phagocyte. Pathogenic Histoplasma yeast cells, but not avirulent mycelial cells, secrete the Eng1 protein, which is a member of the glycosylhydrolase 81 (GH81) family. We show that Histoplasma Eng1 is a glucanase that hydrolyzes β-(1,3)-glycosyl linkages but is not required for Histoplasma growth in vitro or for cell separation. However, Histoplasma yeasts lacking Eng1 function have attenuated virulence in vivo, particularly during the cell-mediated immunity stage. Histoplasma yeasts deficient for Eng1 show increased exposure of cell wall β-glucans, which results in enhanced binding to the Dectin-1 β-glucan receptor. Consistent with this, Eng1-deficient yeasts trigger increased tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) cytokine production from macrophages and dendritic cells. While not responsible for large-scale cell wall structure and function, the secreted Eng1 reduces levels of exposed β-glucans at the yeast cell wall, thereby diminishing potential recognition by Dectin-1 and proinflammatory cytokine production by phagocytes. In α-glucan-producing Histoplasma strains, Eng1 acts in concert with α-glucan to minimize β-glucan exposure: α-glucan provides a masking function by covering the β-glucan-rich cell wall, while Eng1 removes any remaining exposed β-glucans. Thus, Histoplasma Eng1 has evolved a specialized pathogenesis function to remove exposed β-glucans, thereby enhancing the ability of yeasts to escape detection by host phagocytes. IMPORTANCE The success of Histoplasma capsulatum as an intracellular pathogen results, in part, from an ability to minimize its detection by receptors on phagocytic cells of the immune system. In this study, we showed that Histoplasma pathogenic yeast cells, but not avirulent mycelia, secrete a β-glucanase, Eng1, which reduces recognition of fungal cell wall β-glucans. We demonstrated that the Eng1 β-glucanase promotes Histoplasma virulence by reducing levels of surface-exposed β-glucans on yeast cells, thereby enabling Histoplasma yeasts to escape detection by the host β-glucan receptor, Dectin-1. As a consequence, phagocyte recognition of Histoplasma yeasts is reduced, leading to less proinflammatory cytokine production by phagocytes and less control of Histoplasma infection in vivo Thus, Histoplasma yeasts express two mechanisms to avoid phagocyte detection: masking of cell wall β-glucans by α-glucan and enzymatic removal of exposed β-glucans by the Eng1 β-glucanase.
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Affiliation(s)
- Andrew L Garfoot
- Departments of Microbiology and Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
| | - Qian Shen
- Departments of Microbiology and Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
| | - Marcel Wüthrich
- Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Bruce S Klein
- Department of Pediatrics, University of Wisconsin-Madison, Madison, Wisconsin, USA Departments of Medicine and Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Chad A Rappleye
- Departments of Microbiology and Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
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36
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/02/2016] [Indexed: 12/27/2022]
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Xie L, Fang W, Deng W, Yu Z, Li J, Chen M, Liao W, Xie J, Pan W. Global profiling of lysine acetylation in human histoplasmosis pathogen Histoplasma capsulatum. Int J Biochem Cell Biol 2016; 73:1-10. [PMID: 26806293 DOI: 10.1016/j.biocel.2016.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 12/29/2015] [Accepted: 01/15/2016] [Indexed: 11/16/2022]
Abstract
Histoplasma capsulatum is the causative agent of human histoplasmosis, which can cause respiratory and systemic mycosis in immune-compromised individuals. Lysine acetylation, a protein posttranslational protein modification, is widespread in both eukaryotes and prokaryotes. Although increasing evidence suggests that lysine acetylation may play critical roles in fungus physiology, very little is known about its extent and function in H. capsulatum. To comprehensively profile protein lysine acetylation in H. capsulatum, we performed a global acetylome analysis through peptide prefractionation, antibody enrichment, and LC-MS/MS analysis, identifying 775 acetylation sites on 456 acetylated proteins; and functionally analysis showing their involvement in different biological processes. We defined six types of acetylation site motifs, and the results imply that lysine residue of polypeptide with tyrosine at the -1 and +1 positions, histidine at the +1 position, and phenylalanine (F) at the +1 and +2 position is a preferred substrate of lysine acetyltransferase. Moreover, some virulence factors candidates including calmodulin and DnaK are acetylated. In conclusion, our data set may serve as an important resource for the elucidation of associations between functional protein lysine acetylation and virulence in H. capsulatum.
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Affiliation(s)
- Longxiang Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Wenjie Fang
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Wanyan Deng
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Zhaoxiao Yu
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Juan Li
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Min Chen
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Wanqing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China.
| | - Weihua Pan
- Shanghai Key Laboratory of Molecular Medical Mycology, Department of Dermatology, Changzheng Hospital, Second Military Medical University, Shanghai, China.
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Pitangui NDS, Sardi JDCO, Voltan AR, Dos Santos CT, da Silva JDF, da Silva RAM, Souza FO, Soares CP, Rodríguez-Arellanes G, Taylor ML, Mendes-Giannini MJS, Fusco-Almeida AM. An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages. Front Microbiol 2016; 6:1526. [PMID: 26793172 PMCID: PMC4707385 DOI: 10.3389/fmicb.2015.01526] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 12/18/2015] [Indexed: 11/26/2022] Open
Abstract
Histoplasma capsulatum is responsible for a human systemic mycosis that primarily affects lung tissue. Macrophages are the major effector cells in humans that respond to the fungus, and the development of respiratory disease depends on the ability of Histoplasma yeast cells to survive and replicate within alveolar macrophages. Therefore, the interaction between macrophages and H. capsulatum is a decisive step in the yeast dissemination into host tissues. Although the role played by components of cell-mediated immunity in the host's defense system and the mechanisms used by the pathogen to evade the host immune response are well understood, knowledge regarding the effects induced by H. capsulatum in host cells at the nuclear level is limited. According to the present findings, H. capsulatum yeast cells display a unique architectural arrangement during the intracellular infection of cultured murine alveolar macrophages, characterized as a formation of aggregates that seem to surround the host cell nucleus, resembling a “crown.” This extranuclear organization of yeast-aggregates generates damage on the nucleus of the host cell, producing DNA fragmentation and inducing apoptosis, even though the yeast cells are not located inside the nucleus and do not trigger changes in nuclear proteins. The current study highlights a singular intracellular arrangement of H. capsulatum yeast near to the nucleus of infected murine alveolar macrophages that may contribute to the yeast's persistence under intracellular conditions, since this fungal pathogen may display different strategies to prevent elimination by the host's phagocytic mechanisms.
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Affiliation(s)
- Nayla de Souza Pitangui
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Janaina de Cássia Orlandi Sardi
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Aline R Voltan
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Claudia T Dos Santos
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Julhiany de Fátima da Silva
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Rosangela A M da Silva
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Felipe O Souza
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Christiane P Soares
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Gabriela Rodríguez-Arellanes
- Departamento de Microbiologia y Parasitologia, Facultad de Medicina, Universidad Nacional Autónoma de México México City, México
| | - Maria Lucia Taylor
- Departamento de Microbiologia y Parasitologia, Facultad de Medicina, Universidad Nacional Autónoma de México México City, México
| | - Maria J S Mendes-Giannini
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
| | - Ana M Fusco-Almeida
- Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica São Paulo, Brazil
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Isaac DT, Berkes CA, English BC, Murray DH, Lee YN, Coady A, Sil A. Macrophage cell death and transcriptional response are actively triggered by the fungal virulence factor Cbp1 during H. capsulatum infection. Mol Microbiol 2015; 98:910-929. [PMID: 26288377 PMCID: PMC5002445 DOI: 10.1111/mmi.13168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2015] [Indexed: 01/10/2023]
Abstract
Microbial pathogens induce or inhibit death of host cells during infection, with significant consequences for virulence and disease progression. Death of an infected host cell can either facilitate release and dissemination of intracellular pathogens or promote pathogen clearance. Histoplasma capsulatum is an intracellular fungal pathogen that replicates robustly within macrophages and triggers macrophage lysis by unknown means. To identify H. capsulatum effectors of macrophage lysis, we performed a genetic screen and discovered three mutants that grew to wild-type levels within macrophages but failed to elicit host-cell death. Each mutant was defective in production of the previously identified secreted protein Cbp1 (calcium-binding protein 1), whose role in intracellular growth had not been fully investigated. We found that Cbp1 was dispensable for high levels of intracellular growth but required to elicit a unique transcriptional signature in macrophages, including genes whose induction was previously associated with endoplasmic reticulum stress and host-cell death. Additionally, Cbp1 was required for activation of cell-death caspases-3/7, and macrophage death during H. capsulatum infection was dependent on the pro-apoptotic proteins Bax and Bak. Taken together, these findings strongly suggest that the ability of Cbp1 to actively program host-cell death is an essential step in H. capsulatum pathogenesis.
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Affiliation(s)
- Dervla T. Isaac
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
| | - Charlotte A. Berkes
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
- Department of Biology, Merrimack College, North Andover, MA
| | - Bevin C. English
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
| | - Davina Hocking Murray
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
| | - Young Nam Lee
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
| | - Alison Coady
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
| | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143-0414
- Howard Hughes Medical Institute, San Francisco, CA
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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] [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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Liu J, Pan T, You X, Xu Y, Liang J, Limpanont Y, Sun X, Okanurak K, Zheng H, Wu Z, Lv Z. SjCa8, a calcium-binding protein from Schistosoma japonicum, inhibits cell migration and suppresses nitric oxide release of RAW264.7 macrophages. Parasit Vectors 2015; 8:513. [PMID: 26445908 PMCID: PMC4597762 DOI: 10.1186/s13071-015-1119-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 09/28/2015] [Indexed: 11/10/2022] Open
Abstract
Background Schistosomiasis is considered second only to malaria as the most devastating parasitic disease in tropical countries. Schistosome cercariae invade the host by penetrating the skin and migrate though the lungs and portal circulation to their final destination in the hepatic portal system and eventually the mesenteric veins. Previous studies have shown that the cytotoxic pathways that target schistosomulum in the lung-stage involve nitric oxide (NO) produced by macrophages. By contrast, skin-stage schistosomulas can evade clearance, indicating that they might be freed from macrophage NO-mediated cytotoxicity to achieve immune evasion; however, the critical molecules and mechanisms involved remain unknown. Methods Recombinant SjCa8 (rSjCa8), an 8-kDa calcium-binding protein that is stage-specifically expressed in cercaria and early skin-stage schistosomulas of Schistosoma japonicum, was incubated with mouse RAW264.7 macrophages. Effects on macrophage proliferation were determined using Cell Counting Kit-8. Next, transwell assay was carried out to further investigate the role of rSjCa8 in macrophage migration. The effects of rSjCa8 on macrophage apoptosis were evaluated using confocal microscopy and flow cytometry. Additional impacts of rSjCa8 on NO release by lipopolysaccharide (LPS)-stimulated macrophages as well as the underlying mechanisms were explored using fluorescent probe, nitric oxide signaling pathway microarray, quantitative real-time PCR, mutagenesis, and neutralizing antibody approaches. Results rSjCa8 exhibited a striking inhibitory effect on macrophage migration, but did not markedly increase cell proliferation or apoptosis. Additionally, rSjCa8 potently inhibited NO release by LPS-stimulated macrophages in a dose- and time-dependent manner, and the inhibitory mechanism was closely associated with intracellular Ca2+ levels, the up-regulation of catalase expression, and the down-regulation of the expression of 47 genes, including Myc, Gadd45a, Txnip, Fas, Sod2, Nos2, and Hmgb1. Vaccination with rSjCa8 increased NO concentration in the challenging skin area of infected mice and reduced the number of migrated schistosomula after skin penetration by cercariae. Conclusions Our findings indicate that SjCa8 might be a novel molecule that plays a critical role in immune evasion by S. japonicum cercaria during the process of skin penetration. The inhibitory impacts of rSjCa8 on macrophage migration and [Ca2+]i-dependent NO release suggest it might represent a novel vaccine candidate and chemotherapeutic target for the prevention and treatment of schistosomiasis. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1119-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ji Liu
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Tong Pan
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Xu You
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Yiyue Xu
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Jinyi Liang
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Yanin Limpanont
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
| | - Xi Sun
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Kamolnetr Okanurak
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand.
| | - Huanqin Zheng
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Zhongdao Wu
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Zhiyue Lv
- Zhongshan School of Medicine, Sun Yat-sen University, 74 2nd Zhongshan Road, Guangzhou, 510080, China. .,Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, 510080, China.
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42
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 01/19/2023] Open
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43
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Gilmore SA, Voorhies M, Gebhart D, Sil A. Genome-Wide Reprogramming of Transcript Architecture by Temperature Specifies the Developmental States of the Human Pathogen Histoplasma. PLoS Genet 2015; 11:e1005395. [PMID: 26177267 PMCID: PMC4503680 DOI: 10.1371/journal.pgen.1005395] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/26/2015] [Indexed: 11/28/2022] Open
Abstract
Eukaryotic cells integrate layers of gene regulation to coordinate complex cellular processes; however, mechanisms of post-transcriptional gene regulation remain poorly studied. The human fungal pathogen Histoplasma capsulatum (Hc) responds to environmental or host temperature by initiating unique transcriptional programs to specify multicellular (hyphae) or unicellular (yeast) developmental states that function in infectivity or pathogenesis, respectively. Here we used recent advances in next-generation sequencing to uncover a novel re-programming of transcript length between Hc developmental cell types. We found that ~2% percent of Hc transcripts exhibit 5’ leader sequences that differ markedly in length between morphogenetic states. Ribosome density and mRNA abundance measurements of differential leader transcripts revealed nuanced transcriptional and translational regulation. One such class of regulated longer leader transcripts exhibited tight transcriptional and translational repression. Further examination of these dually repressed genes revealed that some control Hc morphology and that their strict regulation is necessary for the pathogen to make appropriate developmental decisions in response to temperature. Eukaryotic cells alter their developmental programs in response to environmental signals. Histoplasma capsulatum (Hc), a ubiquitous fungal pathogen of humans, establishes unique transcriptional programs to specify growth in either a multicellular hyphal form or unicellular yeast form in response to temperature. Since hyphae and yeast are specialized to function in infectivity or pathogenesis, respectively, Hc provides a clinically relevant system in which to query eukaryotic regulatory processes. Here we used next-generation sequencing approaches to annotate the transcriptomes of four distinct Hc strains in response to temperature. We found that a fraction of Hc transcripts have differential transcript architecture in hyphae and yeast, exhibiting 5’ leader sequences that differ markedly in length between morphogenetic states. To begin to understand the effect of these differential leader sequences on expression, we performed the first ribosome density and mRNA abundance measurements in Hc, thereby uncovering transcriptional and translational control that contribute to cell-type regulation.
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Affiliation(s)
- Sarah A. Gilmore
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Mark Voorhies
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Dana Gebhart
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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44
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Hariri OR, Minasian T, Quadri SA, Dyurgerova A, Farr S, Miulli DE, Siddiqi J. Histoplasmosis with Deep CNS Involvement: Case Presentation with Discussion and Literature Review. J Neurol Surg Rep 2015; 76:e167-72. [PMID: 26251798 PMCID: PMC4520962 DOI: 10.1055/s-0035-1554932] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/06/2015] [Indexed: 02/02/2023] Open
Abstract
Central nervous system (CNS) histoplasmosis is rare and difficult to diagnose because it is often overlooked or mistaken for other pathologies due to its nonspecific symptoms. A 32-year-old Hispanic man with advanced acquired immunodeficiency virus presented with altered mental status and reported confusion for the past 3 months. He had a Glasgow Coma Scale of 12, repetitive nonfluent speech, and a disconjugate gaze with a right gaze preference. Lung computed tomography (CT) findings indicated a pulmonary histoplasmosis infection. Magnetic resonance imaging of the brain revealed a ring-enhancing lesion in the left caudate nucleus. A CT-guided left retroperitoneal node biopsy was performed and indicated a benign inflammatory process with organisms compatible with fungal yeast. Treatment with amphotericin B followed by itraconazole was initiated in spite of negative cerebrospinal fluid (CSF) cultures and proved effective in mitigating associated CNS lesions and resolving neurologic deficits. The patient was discharged 3 weeks later in stable condition. Six weeks later, his left basal ganglia mass decreased. Early recognition of symptoms and proper steps is key in improving outcomes of CNS histoplasmosis. Aggressive medical management is possible in the treatment of intracranial deep mass lesions, and disseminated histoplasmosis with CNS involvement can be appropriately diagnosed and treated, despite negative CSF and serology studies.
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Affiliation(s)
- Omid R Hariri
- Department of Neurosurgery, Arrowhead Regional Medical Center, Colton, California, United States
| | - Tanya Minasian
- Department of Neurosurgery, Arrowhead Regional Medical Center, Colton, California, United States
| | - Syed A Quadri
- Department of Neurosurgery, Arrowhead Regional Medical Center, Colton, California, United States
| | - Anya Dyurgerova
- Division of Neurosurgery, Department of Surgery, Western University of Health Sciences, Pomona, California, United States
| | - Saman Farr
- Division of Neurosurgery, Department of Surgery, Western University of Health Sciences, Pomona, California, United States
| | - Dan E Miulli
- Department of Neurosurgery, Arrowhead Regional Medical Center, Colton, California, United States
| | - Javed Siddiqi
- Department of Neurosurgery, Arrowhead Regional Medical Center, Colton, California, United States
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45
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Polvi EJ, Li X, O’Meara TR, Leach MD, Cowen LE. Opportunistic yeast pathogens: reservoirs, virulence mechanisms, and therapeutic strategies. Cell Mol Life Sci 2015; 72:2261-87. [PMID: 25700837 PMCID: PMC11113693 DOI: 10.1007/s00018-015-1860-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 02/06/2015] [Accepted: 02/11/2015] [Indexed: 12/21/2022]
Abstract
Life-threatening invasive fungal infections are becoming increasingly common, at least in part due to the prevalence of medical interventions resulting in immunosuppression. Opportunistic fungal pathogens of humans exploit hosts that are immunocompromised, whether by immunosuppression or genetic predisposition, with infections originating from either commensal or environmental sources. Fungal pathogens are armed with an arsenal of traits that promote pathogenesis, including the ability to survive host physiological conditions and to switch between different morphological states. Despite the profound impact of fungal pathogens on human health worldwide, diagnostic strategies remain crude and treatment options are limited, with resistance to antifungal drugs on the rise. This review will focus on the global burden of fungal infections, the reservoirs of these pathogens, the traits of opportunistic yeast that lead to pathogenesis, host genetic susceptibilities, and the challenges that must be overcome to combat antifungal drug resistance and improve clinical outcome.
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Affiliation(s)
- Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Room 4368, Toronto, ON M5S 1A8 Canada
| | - Xinliu Li
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Room 4368, Toronto, ON M5S 1A8 Canada
| | - Teresa R. O’Meara
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Room 4368, Toronto, ON M5S 1A8 Canada
| | - Michelle D. Leach
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Room 4368, Toronto, ON M5S 1A8 Canada
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Medical Sciences Building, Room 4368, Toronto, ON M5S 1A8 Canada
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46
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Brook CE, Dobson AP. Bats as 'special' reservoirs for emerging zoonotic pathogens. Trends Microbiol 2015; 23:172-80. [PMID: 25572882 PMCID: PMC7126622 DOI: 10.1016/j.tim.2014.12.004] [Citation(s) in RCA: 300] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/25/2014] [Accepted: 12/03/2014] [Indexed: 12/23/2022]
Abstract
The ongoing West African Ebola epidemic highlights a recurring trend in the zoonotic emergence of virulent pathogens likely to come from bat reservoirs that has caused epidemiologists to ask 'Are bats special reservoirs for emerging zoonotic pathogens?' We collate evidence from the past decade to delineate mitochondrial mechanisms of bat physiology that have evolved to mitigate oxidative stress incurred during metabolically costly activities such as flight. We further describe how such mechanisms might have generated pleiotropic effects responsible for tumor mitigation and pathogen control in bat hosts. These synergisms may enable 'special' tolerance of intracellular pathogens in bat hosts; paradoxically, this may leave them more susceptible to immunopathological morbidity when attempting to clear extracellular infections such as 'white-nose syndrome' (WNS).
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Affiliation(s)
- Cara E Brook
- Princeton University, Department of Ecology and Evolutionary Biology, 105 Guyot Hall, Princeton University, Princeton, NJ 08544, USA.
| | - Andrew P Dobson
- Princeton University, Department of Ecology and Evolutionary Biology, 105 Guyot Hall, Princeton University, Princeton, NJ 08544, USA
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47
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Sil A, Andrianopoulos A. Thermally Dimorphic Human Fungal Pathogens--Polyphyletic Pathogens with a Convergent Pathogenicity Trait. Cold Spring Harb Perspect Med 2014; 5:a019794. [PMID: 25384771 PMCID: PMC4526722 DOI: 10.1101/cshperspect.a019794] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Fungi are adept at changing their cell shape and developmental program in response to signals in their surroundings. Here we focus on a group of evolutionarily related fungal pathogens of humans known as the thermally dimorphic fungi. These organisms grow in a hyphal form in the environment but shift their morphology drastically within a mammalian host. Temperature is one of the main host signals that initiates their conversion to the "host" form and is sufficient in the laboratory to trigger establishment of this host-adapted developmental program. Here we discuss the major human pathogens in this group, which are Blastomyces dermatiditis, Coccidioides immitis/posadasii, Histoplasma capsulatum, Paracoccidioides brasiliensis/lutzii, Sporothrix schenckii, and Talaromyces marneffei (formerly known as Penicillium marneffei). The majority of these organisms are primary pathogens, with the ability to cause disease in healthy humans who encounter them in endemic areas.
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Affiliation(s)
- Anita Sil
- Department of Microbiology and Immunology, University of California, San Francisco, California 94143
| | - Alex Andrianopoulos
- Department of Genetics, The University of Melbourne, Victoria 3010, Australia
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48
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Abstract
Morphogenesis in fungi is often induced by extracellular factors and executed by fungal genetic factors. Cell surface changes and alterations of the microenvironment often accompany morphogenetic changes in fungi. In this review, we will first discuss the general traits of yeast and hyphal morphotypes and how morphogenesis affects development and adaptation by fungi to their native niches, including host niches. Then we will focus on the molecular machinery responsible for the two most fundamental growth forms, yeast and hyphae. Last, we will describe how fungi incorporate exogenous environmental and host signals together with genetic factors to determine their morphotype and how morphogenesis, in turn, shapes the fungal microenvironment.
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Affiliation(s)
- Xiaorong Lin
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - J Andrew Alspaugh
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina 27710
| | - Haoping Liu
- Department of Biological Chemistry, University of California, Irvine, California 92697
| | - Steven Harris
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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49
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Abstract
Few among the millions of fungal species fulfill four basic conditions necessary to infect humans: high temperature tolerance, ability to invade the human host, lysis and absorption of human tissue, and resistance to the human immune system. In previously healthy individuals, invasive fungal disease is rare because animals' sophisticated immune systems evolved in constant response to fungal challenges. In contrast, fungal diseases occur frequently in immunocompromised patients. Paradoxically, successes of modern medicine have put increasing numbers of patients at risk for invasive fungal infections. Uncontrolled HIV infection additionally makes millions vulnerable to lethal fungal diseases. A concerted scientific and social effort is needed to meet these challenges.
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Affiliation(s)
- Julia R Köhler
- Division of Infectious Diseases, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Arturo Casadevall
- Departments of Microbiology and Immunology and Medicine, Division of Infectious Diseases, Albert Einstein College of Medicine, New York, New York 10461
| | - John Perfect
- Division of Infectious Diseases, Duke Medical Center, Durham, North Carolina 27710
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50
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Holbrook ED, Kemski MM, Richer SM, Wheat LJ, Rappleye CA. Glycosylation and immunoreactivity of the Histoplasma capsulatum Cfp4 yeast-phase exoantigen. Infect Immun 2014; 82:4414-25. [PMID: 25114108 PMCID: PMC4187849 DOI: 10.1128/iai.01893-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/02/2014] [Indexed: 11/20/2022] Open
Abstract
The yeast phase of Histoplasma capsulatum is the virulent form of this thermally dimorphic fungal pathogen. Among the secreted proteome of Histoplasma, culture filtrate protein 4 (Cfp4) is a heavily glycosylated factor produced abundantly and specifically by Histoplasma yeast cells, suggesting its role in pathogenesis. We have generated three monoclonal antibodies as tools for characterization and detection of Cfp4 and determined the epitope each recognizes. Through site-directed mutagenesis of Cfp4, we identified three asparagines that function as the principal sites of N-linked glycan modification. To test the function of Cfp4 in Histoplasma pathogenesis, we generated Cfp4-deficient strains by insertional mutagenesis and by RNA interference. Cfp4-deficient strains are not attenuated in virulence in human macrophages or during lung infection in a murine model of histoplasmosis. Coinfection of differentially marked Cfp4-producing and Cfp4-deficient strains demonstrates that production of Cfp4 does not confer a fitness advantage to Histoplasma yeasts during murine lung infection. Despite no apparent role in acute virulence in mice, secretion of the Cfp4 glycoprotein by yeast cells is consistent across clinical and laboratory isolates of the North American type 1 and type 2 phylogenetic groups as well as a strain from Panama. In addition, human immune sera recognize the Histoplasma Cfp4 protein, confirming Cfp4 production during infection of human hosts. These results suggest the potential utility of Cfp4 as a diagnostic exoantigen for histoplasmosis.
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Affiliation(s)
- Eric D Holbrook
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
| | - Megan M Kemski
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
| | | | | | - Chad A Rappleye
- Department of Microbiology, Department of Microbial Infection and Immunity, Ohio State University, Columbus, Ohio, USA
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